Composition and Biological Activities of Hydrolyzable Tannins of Fruits

Review pubs.acs.org/JAFC

Composition and Biological Activities of Hydrolyzable Tannins of Fruits of Phyllanthus emblica Baoru Yang* and Pengzhan Liu Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland ABSTRACT: Fruits of emblic leafflower have been used as food and traditional medicine in Asia. A wide range of biological activities have been shown in modern research suggesting potential of the fruits as healthy food and raw material for bioactive ingredients of food. Hydrolyzable tannins are among the major bioactive components of the fruits. Mucic acid gallate, mucic acid lactone gallate, monogalloylglucose, gallic acid, digalloylglucose, putranjivain A, galloyl-HHDP-glucose, elaeocarpusin, and chebulagic acid are the most abundant hydrolyzable tannins. The compositional profiles of tannins in the fruits vary depending on the cultivars as well as ripening stages. Fruits and tannin-rich extracts of fruits have shown antidiabetic, antimicrobial, antiinflammatory, and immune-regulating activities in vitro and in animal studies. The fruits and fruit extracts have manifested protective effects on organs/tissues from damages induced by chemicals, stresses, and aging in animal models. The fruits and fruit extracts have potential in inhibiting the growth of cancer cells and reducing DNA damage induced by chemicals and radiation. Antioxidative activities are likely among the mechanisms of the biological activities and physiological effects. Human intervention/clinical studies are needed to investigate the bioavailability and metabolism of the tannins and to substantiate the health benefits in humans. Emblic leafflower may be a potential raw material for natural food preservatives. KEYWORDS: emblic leafflower, hydrolyzable tannins, elaecocarpusin, chebulagic acid, bioactive ingredients, nutraceuticals

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INTRODUCTION The importance of food and diet in maintaining health and reducing the risk of chronic diseases is increasingly recognized. There is a fast-growing trend in the demand for foods with targeted health-promoting properties. The food industry is searching for new raw materials as sources of bioactive ingredients for foods and nutraceuticals. Hydrolyzable tannins are derived by gallic acid (3,4,5trihydroxybenzoic acid) being esterified to a core polyol, and the galloyl groups may be further esterified or cross-linked through dehydration to yield more complex hydrolyzable tannins.1 Hydrolyzable tannins cover a wide group of compounds belonging to ellagitannins (esters of ellagic acid) and gallotannins (esters of gallic acid) that are present in many plant families. These compounds are gaining increasing attention of researchers in the areas of food and medicine because they are found to have a number of biological properties, including antioxidant, anticancer, antiatherosclerotic, antihepatotoxic, antibacterial, and anti-HIV replication activities.2,3 Emblic leafflower (Phyllanthus emblica) is a tropical fruitbearing tree commonly planted in southern China, India, and other Asian countries. The fruits are consumed fresh and are also processed into food products in these regions. The fruits have been used in traditional medicines to treat various illnesses in Siddha, Sri Lanka, India, and China.4 Recently, there has been increasing interest in the fruits as a raw material for food and nutraceuticals as well as bioactive ingredients of food and personal care products because of the traditional use and the biological activities shown in modern research. A wide array of biological activities and potential health benefits have been reported for emblic leafflower, including antioxidative, antidiabetic, antibacterial, hypolipidemic, anticancer, immunomo© 2013 American Chemical Society

dulatory, anti-inflammatory, and antiatherogenic properties as well as protective effects on the liver, gastric mucosa, and cardiovascular and nervous systems.5−10 The materials studied are fresh fruits, fruit juice, and dried fruits, as well as extracts prepared with various solvents. The protocols applied in the studies carried out so far are mostly in vitro studies and animal experiments. Most of the studies have suggested that the phenolic compounds consisting of primarily hydrolyzable tannins of the fruits are the key bioactive components contributing to the beneficial effects. Several research groups have investigated the tannins of emblic leafflower fruits. This review summarizes the current literature on the compositional profile and the biological activities of hydrolyzable tannins of emblic leafflower fruits, juices, and various extracts of the fruits. The aim is to provide guidance for future research and application of this fruit as a source of bioactive ingredients of food.

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HYDROLYZABLE TANNINS IN FRUITS OF PHYLLANTHUS EMBLICA Hydrolyzable tannins are the dominating phenolic compounds of the fruits of P. emblica.11,12 The tannin content is reported to be 4% of fresh weight in fruit13 and 35% in dried fruit powder.14 The highest content of tannins is found at the early development stage of the fruits.15 Tannins have been investigated in freeze-dried juice,16 aqueous acetone (60%) extract of juice powder,17,18 enzymeaided water extract of fruits,19 water extract of fresh fruits,16 Received: Revised: Accepted: Published: 529

October 23, 2013 December 21, 2013 December 26, 2013 December 26, 2013 dx.doi.org/10.1021/jf404703k | J. Agric. Food Chem. 2014, 62, 529−541

Journal of Agricultural and Food Chemistry

Review

Figure 1. Simple esters and derivatives of gallic acid in P. emblica fruits.

Figure 2. Hydrolyzable tannins in P. emblica fruits.

ethyl acetate extract of fresh fruits,19 aqueous acetone (70%)

molecules of hydrolyzable tannins (Figure 2) have been reported in the fruits and juices of P. emblica. Simple esters of gallic acid reported in P. emblica fruits and juices (Figure 1) include L-malic 2-O-gallate,17 mucic acid 2-Ogallate,17,19 mucic acid 1,4-lactone 2-O-gallate,19 mucic acid 1,4-

20

extract of dried fruit powder, aqueous methanol (60%) extract of dried fruits,21 and methanol extract of dried fruits.12 Both simple esters and derivatives of gallic acid (Figure 1) and large 530

dx.doi.org/10.1021/jf404703k | J. Agric. Food Chem. 2014, 62, 529−541

fruits and extracts

PE fruit extract (an aqueous fruit extract dry powder, including 49.5% tannins)

PE fruit aqueous extract

alcohol-induced oxidative changes in rats, in vivo

ochratoxin-induced LPO in the kidney and liver of mice, in vivo

SunAmla/ethyl acetate extract of PE fruit

free and bound phenolics of PE fruit

oxidation of DNA, in vitro

oxidative stress during aging process in rats, in vivo

methanolic extract of PE fruit

gallic acid, ellagic acids, emblicanins A and B

methanol extract of PE fruit

NO radicals, in vitro

DPPH• radical, in vitro

DPPH, O2•−, OH•, and NO radicals, in vitro

target and method of study

40/10 mg kg−1 BW per day for 100 days

2 mg per animal per day for 45 days

250 mg kg−1 BW per day for 60 days

dose

result

extract of PE fruit could attenuate age-related renal dysfunction and prevent age-related hyperlipidemia through attenuating oxidative stress in the aging process

significant reduction in the ochratoxin-induced LPO in liver and kidney of mouse were found

PE fruit extract showed ameliorative effects against alcohol-induced oxidative changes in different organs of rats (erythrocyte membrane, plasma, liver, brain); the tannins present in PE fruit extract with antioxidant as well as NOscavenging properties were suggested to contribute to these effects

positive correlation between antioxidant activity and phenolic content was found (R = 0.74); gallic acid and tannic acid were identified as the major antioxidant components in phenolic fractions of PE; the extracts of PE also exhibited significant protection to DNA against oxidative damage

ethyl acetate fraction of methanolic extract of PE fruit showed strong NO-scavenging activity in vitro; gallic acid was found to be a major compound in the ethyl acetate fraction, and geraniin showed the highest NO-scavenging activity among the isolated compounds from the ethyl acetate fraction

all compounds showed activities in scavenging of DPPH• radicals; emblicanins A and B showed highest activities

methanol extract of PE fruit exhibited the highest scavenging activity against DPPH, O2•−, OH•, and NO radicals; the extract also significantly inhibited the oxidation of low-density lipoprotein (LDL) in vitro

Table 1. Antioxidative, Radical-Scavenging, and Antiaging Activities of P. emblica (PE) Fruits and Fruit Extracts ref

19, 32

31

26−30

25

24

23

7

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lactone 3-O-gallate,19 mucic acid 1,4-lactone 5-O-gallate,16 and mucic acid 1,4-lactone 3,5-di-O-gallate.17 Mucic acid 2-Ogallate, mucic acid 1,4-lactone 2-O-gallate, and mucic acid 1,4lactone 5-O-gallate are found to be the major compounds of this group in juice powder.17 3-Ethylgallic acid was also isolated from the fruits.20 Two isomers of mucic acid gallate and several isomers of mucic acid digallate, mucic acid lactone gallate, and mucic acid lactone digallate have been detected in the methanol extract of dried fruits of emblic leafflower.12 Different isomers of mucic acid gallates, mucic acid digallates, and mucic acid lactone digallates tend to reach equilibrium in water solution, indicating the possible impact of sample handling and analytical procedures on the ratios between different isomers.19 Methyl esters of mucic acid gallates, mucic acid 1,4-lactone gallates, and mucic acid 1,4-lactone-digallates have been identified in the fruit juice powder17 and methanol extracts of whole fruits.12 Examples of these compounds are mucic acid dimethyl ester 2O-gallate, mucic acid 1-methyl ester 2-O-gallate, mucic acid 6methyl ester 2-O-gallate, mucic acid 1,4-lactone 6-methyl ester 2-O-gallate, and mucic acid 1,4-lactone 6-methyl ester 5-Ogallate.19 It has been suggested that most of the methyl esters found may have been artifacts generated during the separation process of multiple stages of column chromatography, although a small amount of methyl esters has been detected in an aqueous acetone extract of the juice powder.19 Figure 2 presents the structure of major gallotannins and ellagitannins found in the fruit and juice of emblic leafflower. Complex tannins have been investigated in an aqueous acetone extract of fruit juice powder.18 1(β)-O-, 1(β),6-di-O-, and 1(β),2,3,6-tetra-O-galloylglucose, corilagin, chebulanin, chebulagic acid, elaeocarpusin, punicafolin, tercatain, mallonin, putranjivain A, and phyllanemblinin A have been identified on the basis of mass spectrometric (MS) and nuclear magnetic resonance spectroscopic (NMR) spectra. In the same study, five other compounds named phyllanemblinins B, C, D, E, and F have been isolated and identified from leaves and branches, but not in the fruits, of P. emblica.18 Isostrictinin is found in the aqueous acetone (70%) extract of dried fruit powder.20 In the study of Yang et al., the phenolic compounds in a methanol extract of dried fruits of P. emblica have been studied systematically by HPLC-DAD and HPLC-ESI(−)-MS combined with column chromatography.12 A mucic acid gallate, three mucic acid lactone gallate isomers, a galloylglucose, gallic acid, a digalloylglucose, putranjivain A, a galloyl-HHDPglucose, elaeocarpusin, and chebulagic acid are the most abundant compounds in the crude methanol extract of the fruits. In addition, 130 peaks are detected, of which 63 are identified/tentatively identified as simple gallic acid derivatives and derivatives of chebulic acid and chebuloylglucose, as well as ellagitannins and flavonoids. Neochebulagic acid, isomers of neochebuloyl galloylglucose (phyllanemblinins D, E, and F), punicalagin, geraniinic acid, ellagic acid glycosides, and quercetin glycosides are reported.12 Many hydrolyzable tannins have been reported in the fruits of P. emblica,12 which remain to be identified by future research. In addition, some contradictory results have been reported concerning the identification of some hydrolyzable tannins in the fruits. For instance, according to Ghosal et al., the fruits of P. emblica contain two hydrolyzable tannins, emblicanin A (2,3di-O-galloyl-4,6-(S)-hexahydroxydiphenoyl-2-ketogluconolactone) and emblicanin B (2,3,4,6-bis(S)-hexahydroxydiphenoyl2-ketogluconolactone) (Figure 2).11 However, Majeed et al. have suggested that the compounds identified as emblicanins A

and B by Ghosal et al. are 1(β)-O-galloylglucose and mucic acid 1,4-lactone 5-O-gallate, respectively, according to the NMR spectra.16 Thus, the presence of emblicanin A and emblicanin B needs confirmation by further studies. Both the origin of the samples and methods of sample preparation could influence the content and profile of hydrolyzable tannins. Corilagin, geraniin, chebulagic acid, and ellagic acid are found to be the major ellagitannins in both an enzyme-aided water extract and an ethyl acetate extract of fresh fruits of P. emblica. 19 Eleaocarpusin, a major compound in the water extract, is not detected in the ethyl acetate extract of the fruits. Furosin is more abundant in the ethyl acetate extract than in the enzymeaided water extract.19 A recent study has shown clear differences in both the content and profile of tannins in the fruits of emblic leafflower of different origins in southern China.12 Fruits of two cultivars from Guangxi province are richer sources of tannins than those of Tian Chuan emblic leafflower from Fujian province.12 The fruits from Guangxi differ from those from Fujian also by higher proportions of ellagitannins and derivatives of chebulic acid and chebuloylglucose.12

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HEALTH EFFECTS OF HYDROLYZABLE TANNINS OF PHYLLANTHUS EMBLICA FRUITS Many studies have demonstrated that the P. emblica fruits and its extracts have beneficial effects on the health of human beings. Several studies have tested the compounds of purified hydrolyzable tannins; others used whole berries and extracts of different solvents. However, the hydrolyzable tannins were considered as the major bioactive compounds in the materials tested in most of the studies. Antioxidant, Radical-Scavenging, and Antiaging Activities. An excess generation of free radicals is linked to many human diseases and early aging. Reactive oxygen species [ROS; superoxide anion radicals (O2•−), hydroxyl radicals (OH•), and hydrogen peroxide (H2O2)] and reactive nitrogen species [RNS; nitric oxide (NO) and peroxynitrite (ONOO−)] cause oxidation of lipids, proteins, and DNA, damage the structures and functions of cells, and lead to aging and development of diseases.22 Table 1 summarizes the literature on the antioxidative and radical-scavenging activities of P. emblica fruit or its extracts. The free radical-scavenging activity of extracts and individual compounds of P. emblica fruits have been evaluated in vitro.7,23−25 Methanol and aqueous extracts of the fruits have exhibited scavenging activity against 2,2-diphenylpicrylhydrazyl radical (DPPH•), O2•−, OH•, and NO radicals7,24 and inhibited the oxidation of low-density lipoprotein (LDL)6 and DNA.25 Emblicanins A and B are reported to have DPPH•-scavenging activity close to 10 times that of ascorbic acid and twice of that of gallic acid.23 Geraniin has been identified as the compound with the highest NO-scavenging activity in an aqueous extract of P. emblica fruit.24 Gallic acid and tannic acid are the major antioxidant components in phenolic fractions of P. emblica fruits according to both DPPH•-scavenging and reducing power assays.25 A series of studies have shown the ameliorative effects of a P. emblica fruit extract (a dried powder of aqueous fruit extract with a total content of tannins of 49.5% dry weight) against alcohol-induced oxidative changes in rats, suggesting tannins to be the major antioxidants in the extract.26−30 Administration of the extract [250 mg kg−1 body weight (BW) per day] resulted in a significant (p < 0.05) reduction in NO levels, lipid 532


extract of PE fruit

ethyl acetate extract of PE fruit

PE fruit and an enriched fraction of PE fruit tannins

PE fruit and an enriched fraction of PE fruit tannins

aqueous extract of PE

α-amylase and α-glucosidase, in vitro

fructose-induced metabolic syndrome in rat model

diabetic cataract, in vitro

STZ-induced diabetic cataract in rats, in vivo

diabetic neuropathy in rats, in vivo

1:1 mixture of epigallocatechin-3-gallate and PE extract

PE fruit

normal and diabetic human volunteers, clinical trial

diabetic-uremic patients, clinical trial

fruits and extracts

ethanolic extract of PE fruit


streptozotocin (STZ)-induced type 2 diabetes rats, in vivo

100 mg of EGCG and 100 mg of PE extract 3 times per day

250−1000 mg kg−1 per day

0.2% diet

10 or 20 mg kg−1 BW per day for 2 weeks

1, 2, or 3 g PE fruit powder per day

200 mg kg−1 BW for 45 days

dose

result

the mixture significantly improved antioxidant defense as well as diabetic and atherogenic indices in uremic patients with diabetes

insulin in combination with PE extract not only attenuated the diabetic condition but also reduced neuropathic pain through modulation of oxidative−nitrosative stress in diabetic rats

supplements of PE fruit and PE fruit tannins delayed cataract progression

aqueous extract of PE fruit inhibited aldose reductase (AR) of rat lens and recombinant human AR with IC50 values of 0.72 and 0.88 mg mL−1, respectively,

ethyl acetate extract of PE fruit ameliorated the high fructose diet-induced hypertriacylglycerolemia and hypercholesterolemia

extract of PE fruit was able to inhibit α-amylase and α-glucosidase (IC50 value = 1.0 and 94.3 μg mL−1, respectively)

decrease (p < 0.05) was found in fasting and 2 h postprandial blood glucose levels in both normal and diabetic subjects receiving PE powder; significant (p < 0.05) decreases were observed in TC and triglycerides in both normal and diabetic volunteers that were given either 2 or 3 g PE powder per day; the diabetic volunteers receiving 3 g of PE powder per day exhibited a significant (p < 0.05) decrease in total lipids; both normal and diabetic volunteers receiving 2 or 3 g of PE powder showed significant (p < 0.05) improvement in cholesterol levels

significant reduction in blood glucose and significant increase in plasma insulin in diabetic rats

Table 2. Effects of P. emblica (PE) Fruits and Fruit Extracts on Diabetes and Diabetic Complications

39

38

37

36

41

7

35

33

ref


533



Review

peroxidation (LPO), and the activities of Na+/K+- and Mg2+ATPases in erythrocyte membranes in alcohol-treated rats.24 The extract showed hepatoprotective effects, reduced the contents of lipid peroxide and protein carbonyls, and restored the levels of enzymatic and nonenzymatic antioxidants in the liver27,29 and the brain30 of alcohol-treated rats. An ameliorative effect of a P. emblica aqueous extract on ochratoxin-induced LPO in the kidney and liver of mice is reported.31 Both an enzyme-aided water extract and a polyphenol-rich ethyl acetate extract of P. emblica fruits attenuated age-related renal dysfunction and prevented age-related hyperlipidemia by attenuating oxidative stress in the aging process of rats.19,32 Oral administration of the fruit extract also significantly increased the hepatic peroxisome proliferator activated receptor α (PPARα) protein level and inhibited the levels of thiobarbituric acid-reactive substances (TBARS) in the serum, hepatic mitochondria, and kidney in aged rats.19,32 Effects on Sugar Metabolism, Diabetes, and Diabetic Complications. The antidiabetic activities of P. emblica fruits and fruit extracts have been studied in animal models and in humans (Table 2). Oral administration of an ethanol extract of the fruits (200 mg kg−1 BW for 45 days) resulted in a significant reduction in the plasma level of glucose and a significant increase in the plasma level of insulin in streptozotocin (STZ)induced type 2 diabetic rats.33 In addition, administration of the extract reduced total cholesterol (TC), VLDL-C, LDL-C, free fatty acid (FFA), and phospholipid (PL) levels in blood and increased the level of high-density lipoprotein (HDL) cholesterol.33 Oral administration of an aqueous extract of P. emblica seeds reduced fasting glucose level and improved glucose tolerance in normal as well as subdiabetic and mildly diabetic rats.34 Daily supplementation with 1, 2 or 3 g of P. emblica fruit powder for a period of 3 weeks significantly decreased (p < 0.05) fasting and 2 h postprandial levels of blood glucose as well as plasma lipid levels from baseline values in both normal subjects and diabetic patients.33 The antidiabetic properties of P. emblica fruits and extracts are likely to be related to the inhibition of the activities of αglucosidase and α-amylase, enzymes crucial for the digestion and absorption of dietary starch.7 Prolonged exposure to uncontrolled chronic hyperglycemia in diabetes results in complications including various microvascular and macrovascular diseases. Microvascular complications include neuropathy, nephropathy, and vision disorders. Macrovascular complications include heart disease, stroke, and peripheral vascular disease. Studies have shown that P. emblica and its tannins have beneficial effects on cataracts,36,37 neuropathy,38 and uremia39 as complications of diabetes. The studies of Suryanarayana’s group have suggested that P. emblica fruits and the tannins of the fruits might be effective in delaying the development of diabetic cataracts in rats.36,37 An aqueous extract of P. emblica fruit and a fraction rich in tannins of the fruits prevented activation of aldose reductase (AR) and also inhibited sugar-induced osmotic changes in the cultured lens of rat.36 Neither P. emblica fruit nor its tannins showed any preventive effects on STZ-induced hyperglycemia as assessed by blood glucose and insulin levels in rats.37 However, slit lamp microscopic observation indicated that these supplements delayed cataract progression. P. emblica fruit also prevented the aggregation and precipitation of lens proteins caused by hyperglycemia.37 Diabetic neuropathy is one of the most common microvascular complications, affecting >50% of diabetic patients.

Tiwari et al. found that P. emblica fruits could correct functional, biochemical, and molecular defects in experimental diabetic neuropathy by targeting the inflammatory cascade mediated by oxido-nitrosative stress.38 Treatment with an aqueous extract of the fruits (250−1000 mg kg−1 per day) significantly attenuated oxidative stress and the levels of nitrite and cytokines [tumor necrosis factor-α (TNF-α), interleukin1β (IL-1β), and transforming growth factor- β1 (TGF-β1)] both in the serum and in the sciatic nerve in a dose-dependent manner in diabetic rats.38 Oral administration of a mixture of epigallocatechin-3-gallate and P. emblica fruit extract for 3 months significantly improved the antioxidative defenses as well as the diabetic and atherogenic indices in uremic patients with diabetes.39 Metabolic syndrome is characterized by insulin resistance, dyslipidemia, and hypertension and is associated with increased morbidity and mortality from several prevalent diseases, such as diabetes, cancer, myocardial infarction, and stroke.40 An ethyl acetate extract (polyphenol-rich fraction) of P. emblica fruit ameliorated the high fructose diet-induced hypertriacylglycerolemia and hypercholesterolemia in rats.41 Effects on Cardiovascular Health. Fruits and extracts of P. emblica have shown beneficial effects on different cardiovascular diseases (Table 3). Oxygen-derived free radicals play an important role in the initiation and progression of all clinical manifestations of ischemic heart disease. Myocardial cellular injury occurring during reperfusion of ischemic cells, known as ischemia-reperfusion injury, is primarily due to oxidative stress.42 Studies have shown that antioxidants exert a protective effect against cardiac ischemia-reperfusion injury (IRI).43,44 Studies by Bhattcharya et al. and Rajak et al. have shown that tannin-rich extracts of P. emblica fruit can ameliorate the oxidative stress induced by IRI.45,46 Oral administration of a P. emblica fruit extract enriched with emblicanins A and B (50 and 100 mg kg−1 BW twice per day for 14 days) significantly reversed the effects of IRI on superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and LPO activities.45 Similar results have been found in a study by Rajak et al.46 Fresh P. emblica fruit homogenate (250−750 mg kg−1 per day) and saline were administered orally to Wistar albino rats for 30 days. There was a reduction in basal myocardial LPO, as evidenced by decreased TBARS levels, and an augmentation of myocardial endogenous antioxidants in the P. emblica-treated rats compared to those in the saline group. The results indicate that long-term P. emblica fruit administration improves myocardial adaptation by augmenting endogenous antioxidants and protecting the rat heart from oxidative stress associated with IRI.46 Anila and Vijayalakshmi separated flavonoids from P. emblica fruit by solvent extractions and silica gel column chromatography.47 The ethyl acetate/methanol (50:50) fraction provided the maximum yield of flavonoids (789.4 mg from 1.9 kg of fresh fruit). The flavonoids were administered orally (10 mg kg−1 BW per day) to male albino rats fed a high-fat diet (coconut oil 15% and cholesterol 2%). After 90 days of treatment, significant decreases in lipid levels in serum and tissues were observed when compared with the control group.47 Duan et al. studied the antiatherogenic effects of two soluble tannins, corilagin and its analogue Dgg16 (1,6-di-O-galloyl-β-D-glucose), isolated from P. emblica fruit. The results suggested that the two compounds are effective in inhibiting the progress of atherosclerosis by alleviating oxidation injury and by inhibiting 534


tannins (corilagin/Dgg16) isolated from PE fruit

75−300 mg kg−1 BW per day for 5 weeks

extract of PE reduces oxidative stress, prevents development and progression of hypertension as well as cardiac and renal hypertrophy in DOCA/HS-induced hypertension via activation of endothelial nitric oxide synthase (eNOS) and endogenous antioxidants as well as regulation of serum NO and electrolyte levels

49

oxidized LDL-induced proliferation of vascular smooth muscle cell.48 Bhatia et al. investigated the antihypertensive effect of P. emblica fruit extract in a deoxycorticosterone acetate/1% NaCl high salt (DOCA/HS)-induced hypertension model in rat.49 Hypertension was induced in rats by the DOCA/HS (20 mg kg−1, sc) and, at the same time, these rats received cotreatment with different doses of an extract of P. emblica fruit with tannin content of 9.4% (75−300 mg kg−1 BW per day) for 5 weeks. The extract significantly decreased arterial blood pressure and heart rate as well as cardiac and renal hypertrophy in a dosedependent fashion as compared to control rats treated with DOCA alone. Increased TBARS and decreased endogenous antioxidants activity in serum, heart, and kidney tissues of hypertensive rats were also normalized. These results demonstrate that the extract of P. emblica can prevent the development and progression of hypertension as well as cardiac and renal hypertrophy in DOCA/HS-induced hypertension via the activation of endothelial nitric oxide synthase (eNOS) and endogenous antioxidants as well as regulation of serum NO and electrolyte levels.49 Inflammation is involved in multiple aspects of the development of cardiovascular diseases.50 Anti-inflammatory effects of PE fruits and extracts are among the mechanisms supporting vascular health. Anticancer Activities. The anticancer effects of P. emblica fruit have been recently reviewed by Baliga and Dsouza.9 They summarized that P. emblica fruit and its extracts can be used as (1) antineoplastic agents,51,52 (2) radio-protective agents,53,54 and (3) chemopreventive and chemomodulatory agents55−59 to reduce the risk of cancers. The mechanism of the anticancer effects includes the following aspects: P. emblica fruit or its extracts (1) are scavengers of free radicals and decrease oxidation of lipids and other biomolecules; (2) can decrease the hepatic levels of phase I enzymes; (3) can increase the levels of glutathione S-transferase (GST), a phase II enzyme; (4) can decrease levels of ornithine decarboxylase; (5) can increase the levels of antioxidant enzymes; (6) have antimutagenic effects; (7) possess immunomodulatory effects; (8) can modulate the levels of proteins important in cell cycle progression; (9) can induce apoptosis of neoplastic cells; and (10) can prevent metastasis. Table 4 presents a list of studies related to the anticancer effects of P. emblica fruits and fruit extracts. Readers are referred to the paper recently published by Baliga and Dsouza for a thorough review on the topic.9 A few points are worth noticing here. First, the inhibitory efficacy of P. emblica fruit extracts may differ between different cancer cell lines.51 Second, the fruit extracts may work synergistically with some therapeutic cytotoxic agents (doxorubicin and cisplatin) inhibiting the growth of cancer cells.51,52 Third, some shortterm inhibitory effect has been recognized of aqueous extracts of P. emblica fruits on the growth of noncancer cells in vitro.60 Immune-Modulating and Anti-inflammatory Activities. Immune activation is an effective as well as protective approach against infectious diseases. Studies have shown that P. emblica fruits and fruit extracts have immune-modulating and anti-inflammatory activities (Table 5). A 90% ethanol extract of dry P. emblica fruits counter-acted the immune-suppressive effects of chromium(VI) compounds on lymphocytes61 and macrophages62 in vitro. The extract reduced the apoptosis and DNA fragmentation induced by chromium and relieved the suppressive effects of chromium on cell proliferation and production of IL-2 and γ-interferon (γ-IFN) of lymphocytes.61

human umbilical vein endothelial cells, ECV-304, incubated with ox-LDL (50 mg/L), in vitro deoxycorticosterone acetate/1% NaCl high salt (DOCA/HS)induced hypertension model rat

flavonoids separated from PE fruit

cardiac ischemia-reperfusion injury (IRI) in rats rats fed a high-fat diet

Review

extract of PE

48

47

46

PE administration improves myocardial adaptation by augmenting endogenous antioxidants and protects rat hearts from oxidative stress associated with IRI significant decreases in total cholesterol, triacylglycerol, phospholipids, and free fatty acid levels in serum and tissues were observed when compared with the control group corilagin and Dgg16 are effective in inhibiting the progress of atherosclerosis by alleviating oxidation injury and by inhibiting ox-LDL-induced VSMC proliferation 250−750 mg kg−1 per day for 30 days 10 mg kg−1 BW per day for 90 days 0.0001−0.1 mmol L−1

45

result

the PE extract (50 mg and 100 mg kg−1 BW) significantly reversed the effects of IRI on SOD, CAT, GPx, and LPO activities

dose

50 mg and 100 mg kg−1 BW twice per day for 14 days

fruits and extracts

emblicanin A and B enriched PE extract (prepared by eluting fresh PE juice though a Sephadex LH-20 column) fresh PE fruit homogenate


cardiac ischemia-reperfusion injury (IRI) in rats

Table 3. Effects on Cardiovascular Health of P. emblica (PE) Fruits and Fruit Extracts

ref


535


aqueous extract of PE fruit


CA on bone marrow cells induced by aluminum sulfate in mice

hepatocarcinogenesis induced by NDEA in rats


CA on bone marrow cells induced by lead nitrate in mice

fruit pulp of PE


CA on bone marrow cells induced by nickel chloride in mice

mice exposed to 7 Gy of γ-radiation


chromosome aberrations (CA) on bone marrow cells induced by CsCl in mice



Chinese hamster ovary (CHO) cell line

mice exposed to 9 Gy of γ-radiation

aqueous extract of PE

Vero cell line, in vitro; Plasmodium falciparum infected mice, in vivo

plant parts


human hepatocellular carcinoma (HepG2) and lung cancer cells (A549), in vitro

subject and method of study

result

significantly reduced the frequency of CA on bone marrow cells induced by aluminum sulfate in mice


536

50−250 mg kg−1 BW per day for 20 weeks

2.5 g kg−1 BW for 10 days

extract of PE significantly inhibited hepatocarcinogenesis induced by NDEA in a dose-dependent manner

administration of PE significantly increased the total leukocyte count, bone marrow viability, and level of hemoglobin; administration of PE significantly enhanced the activity of the various antioxidant enzymes and GST as well as glutathione system in the blood, and treatment with PE suppressed the elevation in lipid peroxides in the serum

the extract had radioprotective effects; the optimum dose was 100 mg kg−1 BW

significantly reduced the frequency of CA on bone marrow cells induced by lead nitrate in mice


50−800 mg kg−1 BW per day for 7−30 days

significantly reduced the frequency of CA on bone marrow cells induced by nickel chloride in mice

significantly reduced the frequency of CA on bone marrow cells induced by CsCl (125, 250, and 500 mg kg−1 BW) in Swiss albino mice

aqueous extract of PE fruit caused 42% growth inhibition on CHO cells; aqueous extract of PE fruit did not significantly alter the colony-forming efficiency of CHO cells

extract of PE exhibited interesting in vitro and in vivo antiplasmodial activity with good selectivity

PE extract demonstrated growth inhibitory activity, with a certain degree of selectivity between the two cancer cell lines tested; synergistic effects (CI < 1) between PE and doxorubicin as well as between PE and cisplatin were demonstrated on A549 and HepG2 cells at different dose levels



50 μg mL−1

250 mg kg−1 BW per day (in vivo)

4−48 μg mL−1 for A549/25−200 μg mL−1 for HepG2

dose

Table 4. Cytotoxic Effects, Protective Effects against Clastogenicity, and Anticancer Activities of P. emblica (PE) Fruits and Fruit Extracts

59

53

54

58

57

56

55

60

52

51

ref



PE extract can cause immunosuppression in AIA rats

64

Treatment with P. emblica fruit extract increased the survival of cells and restored the phagocytosis and production of cytokines of murine macrophages treated with chromium(VI).62 The cytoprotective and immune-modulating properties of the P. emblica extract were related to protection from oxidative damages induced by chromium treatment by scavenging the free radicals and by maintaining the antioxidative status as well as the levels of antioxidants and antioxidative enzymes.61,62 Intake of P. emblica fruit powder enhanced natural killer (NK) cell activity and antibody-dependent cellular cytotoxicity (ADCC) in syngeneic BALB/c mice bearing Dalton’s lymphoma ascites (DLA) tumors.63 Adjuvant-induced arthritis (AIA) has been widely used as a model for rheumatoid arthritis (RA) and reactive arthritis. Crude water extracts of P. emblica fruit suppressed the immune response in AIA model in rats.64 The anti-inflammatory activities of P. emblica fruits or fruit extracts have been studied in animal models.65,66 Acute pancreatitis is a rapidly developing inflammatory disease of the pancreas. A P. emblica fruit extract (tannin content ≥ 30% weight) has been reported to be effective in the treatment of arginine-induced acute pancreatitis in rats.65 The administration of the extract lowered the serum levels of lipase and interleukin10 in the arginine-treated rats. The nucleic acid content and rate of DNA synthesis in pancreatic tissue, pancreatic proteins, and pancreatic amylase content were significantly improved.65 Muthuraman et al. studied the anti-inflammatory effects of extracts of free and bound phenolic compounds from P. emblica fruits in carrageenan- and cotton pellet-induced models of acute and chronic inflammation in rats at dose levels of 20 and 40 mg extract kg−1 body weight.66 In both acute and chronic inflammation, both the free and bound phenolics of P. emblica reduced inflammation; at high doses, the effects of both fractions were comparable to treatment with diclofenac.66 In this study, free phenolic compounds were extracted with 70% aqueous ethanol, acidified, and further extracted with ethyl acetate. The extract of bound phenolic compounds was prepared by extraction of fruits with sodium hydroxide (1 M) containing sodium borohydride (0.5%), followed by acidification with hydrochloride acid to pH 1.5.66 Ethanolic extract from P. emblica fruit and pyrogallol isolated from the extract were equally effective in inhibiting Pseudomonas aeruginosa-induced expression of the pro-inflammatory genes in bronchial epithelial cells in vitro. These results suggest that pyrogallol is a major bioactive compound responsible for the anti-inflammatory effect of the extracts of P. emblica fruit.67 Antimicrobial and Antidiarrheal Activity. The antimicrobial and cytotoxic activities of P. emblica fruits and fruit extracts have been studied by several research groups.68−70 The antibacterial activity of the fruit extracts against 345 bacterial isolates belonging to 6 different genera of Gram-negative bacteria isolated from urine specimens was evaluated by Saeed and Tariq.69 Aqueous infusion and decoction of P. emblica fruits exhibited potent antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Klebsiella ozaenae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Salmonella paratyphi A, Salmonella paratyphi B, and Serratia marcescens.69 Saini et al. studied the protective effect of P. emblica fruit against Klebsiella pneumoniae-induced pneumonia in mice. The effect of short(15 days) and long-term (30 days) feeding of P. emblica fruit powder in mice over the course of K. pneumoniae ATCC43816 infection in the lungs was studied in terms of bacterial colonization, macrophage activity, malondialdehyde (MDA)

crude extract of PE adjuvant induced arthritic (AIA) rat model

6.25−100 mg kg−1 BW

63 PE enhanced natural killer (NK) cell activity and antibody-dependent cellular cytotoxicity (ADCC) in syngeneic BALB/c mice bearing DLA tumors PE fruit powder mice bearing Dalton’s lymphoma ascites (DLA) tumor

20 mg kg−1 BW per day

62 the presence of the PE extract enhanced cell survival, decreased free radical production, and maintained antioxidant levels close to those of the control cells; furthermore, chromium(VI) treatment resulted in decreased phagocytosis and γ-IFN production, which were restored by the PE extract 70% ethanol extract of PE dry fruit chromium(VI) induced oxidative injury in murine macrophages, in vitro

250 μg mL−1

61 PE extract also inhibited apoptosis and DNA fragmentation induced by Cr, relieved immunosuppressive effects of Cr on lymphocyte proliferation, and restored IL-2 and γ-IFN production considerably; the results showed the fruit extract of PE had cytoprotective and immunomodulatory properties 90% ethanol extract of PE dry fruit lymphocytes, in vitro

10 μg−1 mg mL−1

66 in both acute and chronic inflammation, both free and bound phenolics of PE reduced inflammation 20 and 40 mg kg−1 BW for 6 days free and bound phenolic compounds from PE fruit (70% ethanol extract)

65

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carrageenan and cotton pellet induced acute and chronic inflammatory in rat paw

result

PE treatment was found to be beneficial for treating acute pancreatitis 100 mg kg−1 BW per day for 3, 7, 14, and 28 days

dose plant parts

PE fruit extract induced acute pancreatitis in rats

subject and method

Table 5. Anti-inflammatory and Immunomodulating Activities of P. emblica (PE) Fruits and Fruit Extracts

L-arginine

ref


537



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and nitrite production in the bronchoalveolar lavage fluid.70 TNF-α level in serum was also assessed. The results in the longterm feeding experimental model suggested that supplementation with P. emblica fruits might reduce bacterial colonization in the lung.70 In addition to tannins, alkaloids were suggested to be among the antimicrobial compounds of P. emblica fruits.71 The methanol extract of P. emblica fruit showed a significant inhibitory effect on diarrhea in Wistar albino rats induced by castor oil and magnesium sulfate.70 Oral administration of the extract (50−150 mg kg−1 BW) produced a significant doserelated reduction in gastrointestinal motility in charcoal meal tests in rats. The treatment also significantly inhibited the production of prostaglandin E2 (PGE2)-induced enteropooling.72 The potential of P. emblica for the treatment of diarrhea has been investigated in mice and in isolated rabbit jejunum and guinea pig ileum.73 Oral administration of 70% ethanol crude extract of P. emblica fruits inhibited castor oil-induced diarrhea and intestinal fluid accumulation in mice at 500−700 mg kg−1 BW. The results of the in vitro studies indicate that the P. emblica fruit extract possesses antidiarrheal and spasmolytic activities, possibly through the blockade of muscarinic receptors and Ca2+ channels.73 Hepato- and Gastroprotective Activities. P. emblica fruit and its extract have been shown to have potential in protecting the liver74−77 and the gastric mucosa10,78,79 from injuries induced by chemical agents in experimental models. Moreover, fruit of P. emblica may reverse CCl4- and TAA-induced fibrosis in the liver in rat.80,81 Supplementation of P. emblica fruits decreased nitrosodiethylamine (NDEA)-induced hepatic apoptosis and autophagy via down-regulation of the Bax/Bcl-2 ratio and Beclin-1 expression.74 Administration of an aqueous extract (2 mg/animal/day) of P. emblica fruits for 45 days along with ochratoxin significantly ameliorated ochratoxin-induced reduction in the content of DNA, RNA, and protein in the livers and kidneys in mice.75 Oral administration with an extract of fresh P. emblica fruits (obtained by extraction with 50% ethanol) at a single dose of 25, 50, or 75 mg kg−1, 4 h before ethanol treatment, enhanced liver cell recovery from the damage by ethanol and suppressed the ethanol-induced elevation in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and IL-1β in rats.76 A hydroalcoholic (50%) extract of P. emblica fruit reversed fibrogenic events in the liver in rats80 and showed a protective effect against antituberculosis (anti-TB) drug-induced liver toxicity in hepatocytes in vitro and in vivo.77 In another study, P. emblica fruit reversed CCl4- and TAA-induced prefibrogenic events in rat liver.81 Protective and healing properties of P. emblica fruit and its extracts against gastric ulceration have been studied mostly in animal models.10,78,79 Pretreatment with the butanol fraction of an aqueous extract of P. emblica fruit at a dose of 100 mg kg−1 BW per day, via oral administration to rats for 10 consecutive days, enhanced the secretion of gastric mucus and hexosamine (p < 0.001) in the context of indomethacin-induced ulceration in rats.79 The morphological observation also suggested a protective effect of the extract on the stomach wall. Indomethacin treatment increased SOD and MDA levels in gastric tissue of rats but hardly affected the MDA or SOD levels in animals pretreated with the P. emblica fruit extract.79 A methanolic extract of P. emblica fruits had significant gastroprotective and ulcer-healing effects, which might be due to its effects on both offensive and

defensive mucosal factors.78 A 95% ethanol extract of sun-dried P. emblica fruit (oral administration, 100 mg kg−1 per day) accelerated the healing process of indomethacin-induced ulcers in rats.10 Biphasic activities were reported of an ethanolic extract of P. emblica fruits on gastric ulcers induced by nonsteroidal anti-inflammatory drug (NSAID) in mice, healing effects being observed at low dose but adverse effects at high dose.82 The hepato- and gastroprotective activities of P. emblica fruits and extracts are suggested to be related to the antioxidative and membrane-stabilizing activities.77 Treatment with P. emblica fruit and extracts significantly preserved the expression of SOD and CAT and decreased the expression of inducible nitric oxide synthase (iNOS) and cytochrome P450 2E1 (CYP2E1) proteins in the liver of rats.74,77 Antioxidant properties of P. emblica fruits and fruit extracts appeared to be among the primary factors responsible for the healing effects of the P. emblica extract on gastric ulcer.78,79 Analgesic and Antipyretic Activities and Effects on Nervous System and Skin. P. emblica fruits are traditionally used to treat disorders in the central nervous system (CNS).83 Pretreatment with a hydroalcoholic extract of P. emblica fruits (500 and 700 mg kg−1 ip) increased the latency of seizures and reduced the cognitive deficits induced by kainic acid.83 The extract suppressed the increase in TBARS and TNF-α levels and the decrease in reduced glutathione (GSH) level in the brain in kainic acid-treated rats, suggesting a possible role of antioxidant and anti-inflammatory activities in the neuroprotective effects of P. emblica fruit.83 A memory-enhancing activity of orally adminstered P. emblica fruit was shown in mice.84 The elevated plus maze and passive avoidance apparatus served as the exteroceptive behavioral models for testing memory. Diazepam-, scopolamine- and aging-induced amnesia served as the interoceptive behavioral models. P. emblica produced a dose-dependent improvement in memory scores in young and aged mice and reversed amnesia induced by scopolamine and diazepam and reduced cholinesterase activity in the brain.84 Some studies also suggest that P. emblica fruits possess antipyretic and analgesic activity, skin protective effects, and wound-healing effects.83−88 A single oral dose of ethanol or aqueous extracts of P. emblica fruit (500 mg kg−1 BW, ip) led to a significant reduction in brewer’s yeast-induced hyperthermia in rats.85 Oral administration with the extracts also elicited inhibitory effects on the acetic acid-induced writhing response in mice, suggesting analgesic activity of the extracts.85 P. emblica fruit effectively inhibited UVB-induced photoaging in human skin fibroblasts in vitro likely because of its strong ROSscavenging ability.86 Topical application of a 90% ethanol extract of dried fruit powder speded wound healing through the up-regulation of collagen expression and extracellular signalregulated kinase (ERK1/2) signaling.88 Bioavailability of Hydrolyzable Tannins. The bioavailability of hydrolyzable tannins from various sources has been reviewed.2,89 Most human studies have focused on pomegranate juice with punicalin and punicalagin being the major ellagitannins. Also, the ellagitannins of raspberries, strawberries, walnuts, and oak-aged wines have been studied. Dietary ellagitannins are hydrolyzed, releasing free ellagic acid, which is partly absorbed directly in the stomach and the proximal small intestine. After consumption of pomegranate juice by volunteers, the concentration of ellagic acid reached the maximum 33 ng/mL plasma 1 h after intake.2 Ellagitanins 538



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Funding

and free ellagic acid are metabolized to urolithins by the action of the microbiota in the distal part of the small intestine and the colon. After absorption, urolithins are converted to various derivatives of urolithin-3-O-glucuronide by the action of phase II enzymes.89 The amount of urolithin A 3-O-glucuronide excreted in the urine corresponded to 3−17% of the intake of ellagitannins, depending on the sources.89 Significant variations among individuals have been observed, mostly likely due to differences in the colonic microbiota. Some evidence obtained in Iberian pigs fed oak acorns suggested significant hepatic metabolism of urolithins and enterohepatic circulation of urolithin metabolites.89 The tannins of emblic leafflower are a mixture of ellagitannins and gallotannins. The bioavailability and metabolism of tannins in emblic leafflower have not been reported. Further studies on these aspects would provide useful data for substantiating the physiological effects of these compounds in humans.

We thank the Finnish Cultural Foundation and the Center of International Mobility CIMO (Finland) for financial support. Notes

The authors declare no competing financial interest.

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(1) Hagerman, A. E. Tannin Handbook; Miami University: Oxford, OH, USA, 2002; www.users.muohio.edu/hagermae/. (2) Landete, J. M. Ellagitannins, ellagic acid and their derived metabolites: a review about source, metabolism, functions and health. Food Res. Int. 2011, 44, 1150−1160. (3) Larrosa, M.; García-Conesa, M. T.; Espín, J. C.; Tomás-Barberán, F. A. Ellagitannins, ellagic acid and vascular health. Mol. Aspects Med. 2010, 31, 513−539. (4) Poltanov, E. A.; Shikov, A. N.; Dorman, H. J.; Pozharitskaya, O. N.; Makarov, V. G.; Tikhonov, V. P.; Hiltunen, R. Chemical and antioxidant evaluation of Indian gooseberry (Emblica of f icinalis Gaertn., syn. Phyllanthus emblica L.) supplements. Phytother. Res. 2009, 23, 1309−1315. (5) Khan, K. H. Role of Emblica of f icinalis in medicine − a review. Bot. Res. Int. 2009, 2, 218−228. (6) Krishnaveni, M.; Mirunalini, S. Therapeutic potential of Phyllanthus emblica (amla): the ayurvedic wonder. J. Basic Clin. Physiol. Pharmacol. 2010, 21, 93−105. (7) Nampoothiri, S. V.; Prathapan, A.; Cherian, O. L.; Raghu, K. G.; Venugopalan, V. V.; Sundaresan, A. In vitro antioxidant and inhibitory potential of Terminalia bellerica and Emblica of f icinalis fruits against LDL oxidation and key enzymes linked to type 2 diabetes. Food Chem. Toxicol. 2011, 49, 125−131. (8) Sabu, M. C.; Kuttan, R. Anti-diabetic activity of medicinal plants and its relationship with their antioxidant property. J. Ethnopharmacol. 2002, 81, 155−160. (9) Baliga, M. S.; Dsouza, J. J. Amla (Emblica of f icinalis Gaertn), a wonder berry in the treatment and prevention of cancer. Eur. J. Cancer Prev. 2011, 20, 225−239. (10) Bhattacharya, S.; Chaudhuri, S. R.; Chattopadhyay, S.; Bandyopadhyay, S. K. Healing properties of some Indian medicinal plants against indomethacin-induced gastric ulceration of rats. J. Clin. Biochem. Nutr. 2007, 41, 106−114. (11) Ghosal, S.; Tripathi, V. K.; Chauhan, S. Active constituent of Emblica of f icinalis: part 1the chemistry and antioxidant effects of two new hydrolyzable tannins, emblicanin A and B. Indian J. Chem. 1996, 35B, 941−948. (12) Yang, B.; Kortesniemi, M.; Liu, P.; Salminen, J-P. Analysis of hydrolyzable tannins and other phenolic compounds in emblic leafflower (Phyllanthus emblica L.) fruits by high performance liquid chromatography-electrospray ionization mass spectrometry. J. Agric. Food Chem. 2012, 60, 8672−8683. (13) Jacob, A.; Pandey, M.; Kapoor, S.; Saroja, R. Effect of the Indian gooseberry (amla) on serum cholesterol levels in men aged 35−55 years. Eur. J. Clin. Nutr. 1988, 42, 939−944. (14) Wu, S. X.; Zhou, L. X. An edible value research of Phyllenthus emblica L. Acad. J. Kunming Med. Coll. 1996, 17, 22−23. (15) Chen, G. Q.; Chen, J.; Hu, J. X.; Li, Q. H.; Su, Y. C. Study of composition changes of fruits of Phyllanthus emblica L. during ripening. Chin. Wild Plant Resour. 1995, 2, 31−33. (16) Majeed, M.; Bhat, B.; Jadhav, A. N.; Srivastava, J. S.; Nagabhushanam, K. Ascorbic acid and tannins from Emblica of f icinalis Gaertn. fruitsa revisit. J. Agric. Food Chem. 2009, 57, 220−225. (17) Zhang, Y. J.; Tanaka, T.; Yang, C.; Kouno, I. New phenolic constituents from the fruit juice of Phyllanthus emblica. Chem. Pharm. Bull. (Tokyo) 2001, 49, 537−540. (18) Zhang, Y. J.; Abe, T.; Tanaka, T.; Yang, C. R.; Kouno, I. Phyllanemblinins A−F, new ellagitannins from Phyllanthus emblica. J. Nat. Prod. 2001, 64, 1527−1532. (19) Yokozawa, T.; Kim, H. Y.; Kim, H. J.; Tanaka, T.; Sugino, H.; Okubo, T.; Chu, D. C.; Juneja, L. R. Amla (Emblica of f icinalis Gaertn.)

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PERSPECTS FOR FUTURE RESEARCH From a compositional point of view, the hydrolyzable tannins of emblic leafflower are a very complex mixture of over 100 compounds. Many compounds are either preliminarily identified or unidentified. Some contradictory identifications have been reported. Further research is necessary to provide a detailed characterization of the compounds in the tannin fraction of emblic leafflower. Most of the biological activities and physiological effects of the fruit and fruit extracts have been shown by in vitro studies or in animal models. The data from clinical and human intervention studies are extremely scanty. Ellagitannins and ellagic acid in food have been suggested to have low bioavailability due to the low absorption rate in the small intestine. Most of the dietary ellagitannins are metabolized to urolithins by the microbiota in the colon.1 Urolithins are weaker antioxidants than ellagitannins. They are absorbed to the circulation and may accumulate in certain tissues as various derivatives with estrogenic or antiestrogenic activities. Therefore, it is also worth investigating the estrogenic and antiestrogenic effects of dietary supplementation of the tannin fraction of emblic leafflower in humans. Whereas many studies suggested that antioxidative activities are associated with most of the beneficial effects observed for the fruits and fruit extracts, the molecular biological mechanisms of the biological activities and physiological effects need further study. Extracts of emblic leafflower (P. emblica) fruits and hydrolyzable tannins isolated from some plant materials have been demonstrated to have effects on the expression of some genes related to various aspects of the biological activities. The approach of nutragenomic and metabolomic research shall be applied to investigate the effects of the fruits and extracts of P. emblica on the expression of genes and the metabolomes in humans of different genetic backgrounds and baseline metabolomic profiles. The current literature suggests strong antioxidative and antimicrobial activities of tannin-rich extracts of emblic leafflower fruits. Research shall be carried out to explore the potential of emblic leafflower fruit as a raw material for natural food preservatives.

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REFERENCES

AUTHOR INFORMATION

Corresponding Author

*(B.Y.) Phone: +358 2 333 6844. E-mail: bayang@utu.fi 539



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attenuates age-related renal dysfunction by oxidative stress. J. Agric. Food Chem. 2007, 55, 7744−7752. (20) Zhang, L. Z.; Zhao, W. H.; Guo, Y. J.; Tu, G. Z.; Lin, S.; Xin, L. G. Studies on chemical constituents in fruits of Tibetan medicine Phyllanthus emblica. China J. Chin. Mat. Med. 2003, 28, 940−943. (21) Liu, X.; Cui, C.; Zhao, M.; Wang, J.; Luo, W.; Yang, B.; Jiang, Y. Identification of phenolics in the fruit of emblica (Phyllanthus emblica L.) and their antioxidant activities. Food Chem. 2008, 109, 909−915. (22) Devasagayam, T. P.; Tilak, J. C.; Boloor, K. K.; Sane, K. S.; Ghaskadbi, S. S.; Lele, R. D. Free radicals and antioxidants in human health: current status and future prospects. J. Assoc. Physicians India 2004, 52, 794−804. (23) Pozharitskaya, O. N.; Ivanova, S. A.; Shikov, A. N.; Makarov, V. G. Separation and evaluation of free radical-scavenging activity of phenol components of Emblica of f icinalis extract by using an HPTLCDPPH* method. J. Sep. Sci. 2007, 30, 1250−1254. (24) Kumaran, A.; Karunakaran, R. J. Nitric oxide radical scavenging active components from Phyllanthus emblica L. Plant Foods Hum. Nutr. 2006, 61, 1−5. (25) Kumar, G. S; Nayaka, H.; Dharmesh, S. M.; Slimath, P. V. Free and bound phenolic antioxidants in amla (Emblica of f icinalis) and turmeric (Curcuma longa). J. Food Compos. Anal. 2006, 19, 446−452. (26) Reddy, V. D.; Padmavathi, P.; Paramahamsa, M.; Varadacharyulu, N. Ch. Modulatory role of Emblica of f icinalis against alcohol induced biochemical and biophysical changes in rat erythrocyte membranes. Food Chem. Toxicol. 2009, 47, 1958−1963. (27) Reddy, V. D.; Padmavathi, P.; Varadacharyulu, N. Ch. Emblica of f icinalis protects against alcohol-induced liver mitochondrial dysfunction in rats. J. Med. Food 2009, 12, 327−333. (28) Reddy, V. D.; Padmavathi, P.; Paramahamsa, M.; Varadacharyulu, N. Ch. Amelioration of alcohol-induced oxidative stress by Emblica of f icinalis (amla) in rats. Indian J. Biochem. Biophys. 2010, 47, 20−25. (29) Reddy, V. D.; Padmavathi, P.; Gopi, S.; Paramahamsa, M.; Varadacharyulu, N. Ch. Protective effect of emblica of f icinalis against alcohol-Induced hepatic injury by ameliorating oxidative stress in rats. Indian J. Clin. Biochem. 2010, 25, 419−424. (30) Reddy, V. D.; Padmavathi, P.; Kavitha, G.; Gopi, S.; Varadacharyulu, N. Ch. Emblica of ficinalis ameliorates alcohol-induced brain mitochondrial dysfunction in rats. J. Med. Food 2011, 14, 62−68. (31) Chakraborty, D.; Verma, R. Ameliorative effect of Emblica of f icinalis aqueous extract on ochratoxin-induced lipid peroxidation in the kidney and liver of mice. Int. J. Occup. Environ. Med. 2010, 23, 63− 73. (32) Yokozawa, T.; Kim, H. Y.; Kim, H. J.; Okubo, T.; Chu, D. C.; Juneja, L. R. Amla (Emblica of f icinalis Gaertn.) prevents dyslipidaemia and oxidative stress in the ageing process. Br. J. Nutr. 2007, 97, 1187− 1195. (33) Krishnaveni, M.; Mirunalini, S.; Karthishwaran, K.; Dhamodharan, G. Antidiabetic and antihyperlipidemic properties of Phyllanthus emblica Linn. (Euphorbiaceae) on streptozotocin induced diabetic rats. Pak. J. Nutr. 2010, 9, 43−51. (34) Mehta, S.; Singh, R. K.; Jaiswal, D.; Rai, P. K.; Watal, G. Antidiabetic activity of Emblica of f icinalis in animal models. Pharm. Biol. 2009, 47, 1050−1055. (35) Akhtar, M. S.; Ramzan, A.; Ali, A.; Ahmad, M. Effect of amla fruit (Emblica of f icinalis Gaertn.) on blood glucose and lipid profile of normal subjects and type 2 diabetic patients. Int. J. Food Sci. Nutr. 2011, 62, 609−616. (36) Suryanarayana, P.; Kumar, P. A.; Saraswat, M.; Petrash, J. M.; Reddy, G. B. Inhibition of aldose reductase by tannoid principles of Emblica of f icinalis: implications for the prevention of sugar cataract. Mol. Vis. 2004, 10, 148−154. (37) Suryanarayana, P.; Saraswat, M.; Petrash, J. M.; Reddy, G. B. Emblica of f icinalis and its enriched tannoids delay streptozotocininduced diabetic cataract in rats. Mol. Vis. 2007, 13, 1291−1297. (38) Tiwari, V.; Kuhad, A.; Chopra, K. Emblica of f icinalis corrects functional, biochemical and molecular deficits in experimental diabetic

neuropathy by targeting the oxido-nitrosative stress mediated inflammatory cascade. Phytother. Res. 2011, 25, 1527−1536. (39) Chen, T. S.; Liou, S. Y.; Wu, H. C.; Tsai, F. J.; Tsai, C. H.; Huang, C. Y.; Chang, Y. L. Efficacy of epigallocatechin-3-gallate and amla (Emblica of f icinalis) extract for the treatment of diabetic-uremic patients. J. Med. Food 2011, 14, 718−723. (40) Hwang, I. S.; Ho, H.; Hoffman, B. B.; Reaven, G. M. Fructoseinduced insulin resistance and hypertension in rats. Hypertension 1987, 10, 512−516. (41) Kim, H. Y.; Okubo, T.; Juneja, L. R.; Yokozawa, T. The protective role of amla (Emblica of f icinalis Gaertn.) against fructoseinduced metabolic syndrome in a rat model. Br. J. Nutr. 2010, 103, 502−512. (42) McCord, J. M. Oxygen-derived free radicals in postischaemic tissue injury. N. Engl. J. Med. 1985, 312, 159−163. (43) Haramaki, N.; Packer, L.; Assadnazari, H.; Zimmer, G. Cardiac recovery during post-ischaemic reperfusion is improved by combination of vitamin E with dihydrolipoic acid. Biochem. Biophys. Res. Commun. 1993, 196, 1101−1107. (44) Haramaki, N.; Aggrawal, S.; Kawabata, T.; Droy-Lefaix, M. T.; Packer, L. Effects of natural antioxidant Ginkgo biloba extract (EGb 761) on myocardial ischaemia-reperfusion injury. Free Radical Biol. Med. 1994, 16, 789−794. (45) Bhattacharya, S. K.; Bhattacharya, D.; Sairam, K.; Ghosal, S. Effect of bioactive tannoid principles of Emblica of f icinalis on ischemiareperfusion-induced oxidative stress in rat heart. Phytomedicine 2012, 9, 171−174. (46) Rajak, S.; Banerjee, S. K.; Sood, S.; Dinda, A. K.; Gupta, Y. K.; Gupta, S. K.; Maulik, S. K. Emblica of f icinalis causes myocardial adaptation and protects against oxidative stress in ischemic-reperfusion injury in rats. Phytother. Res. 2004, 18, 54−60. (47) Anila, L.; Vijayalakshmi, N. R. Flavonoids from Emblica of f icinalis and Mangifera indica-effectiveness for dyslipidemia. J. Ethnopharmacol. 2002, 79, 81−87. (48) Duan, W. G; Yu, Y.; Zhang, L. Y. Antiatherogenic effects of Phyllanthus emblica associated with corilagin and its analogue. Yakugaku Zasshi 2005, 125, 587−591. (49) Bhatia, J.; Tabassum, F.; Sharma, A. K.; Bharti, S.; Golechha, M.; Joshi, S.; Sayeed Akhatar, M.; Srivastava, A. K.; Arya, D. S. Emblica of f icinalis exerts antihypertensive effect in a rat model of DOCA-saltinduced hypertension: role of (p) eNOS, NO and oxidative stress. Cardiovasc. Toxicol. 2011, 11, 272−279. (50) Libby, P. Inflammation and cardiovascular disease mechanisms. Am. J. Clin. Nutr. 2006, 83, S456−S460. (51) Pinmai, K.; Chunlaratthanabhorn, S.; Ngamkitidechakul, C.; Soonthornchareon, N.; Hahnvajanawong, C. Synergistic growth inhibitory effects of Phyllanthus emblica and Terminalia bellerica extracts with conventional cytotoxic agents: doxorubicin and cisplatin against human hepatocellular carcinoma and lung cancer cells. World J. Gastroenterol. 2008, 14, 1491−1497. (52) Pinmai, K.; Hiriote, W.; Soonthornchareonnon, N.; Jongsakul, K.; Sireeratawong, S.; Tor-Udom, S. In vitro and in vivo antiplasmodial activity and cytotoxicity of water extracts of Phyllanthus emblica, Terminalia chebula, and Terminalia bellerica. J. Med. Assoc. Thai. 2010, 93, S120−S126. (53) Hari Kumar, K. B.; Sabu, M. C.; Lima, P. S.; Kuttan, R. Modulation of haematopoetic system and antioxidant enzymes by Emblica of f icinalis Gaertn and its protective role against γ-radiation induced damages in mice. J. Radiat. Res. 2004, 45, 549−555. (54) Singh, I.; Sharma, A.; Nunia, V.; Goyal, P. K. Radioprotection of Swiss albino mice by Emblica of f icinalis. Phytother. Res. 2005, 19, 444− 446. (55) Ghosh, A.; Sharma, A.; Talukder, G. Relative protection given by extract of Phyllanthus emblica fruit and an equivalent amount of vitamin C against a known clastogencaesium chloride. Food Chem. Toxicol. 1992, 30, 865−869. (56) Dhir, H.; Roy, A. K.; Sharma, A.; Talukder, G. Modification of clastogenicity of lead and aluminium in mouse bone marrow cells by 540



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dietary ingestion of Phyllanthus emblica fruit extract. Mutat. Res. 1990, 241, 305−312. (57) Dhir, H.; Agarwal, K.; Sharma, A.; Talukder, G. Modifying role of Phyllanthus emblica and ascorbic acid against nickel clastogenicity in mice. Cancer Lett. 1991, 59, 9−18. (58) Roy, A. K.; Dhir, H.; Sharma, A. Modification of metal-induced micronuclei formation in mouse bone marrow erythrocytes by Phyllanthus fruit extract and ascorbic acid. Toxicol. Lett. 1992, 62, 9−17. (59) Jeena, K. J.; Joy, K. L.; Kuttan, R. Effect of Emblica of f icinalis, Phyllanthus amarus and Picrorrhiza kurroa on N-nitrosodiethylamine induced hepatocarcinogenesis. Cancer Lett. 1999, 136, 11−16. (60) Sumantran, V. N.; Boddul, S.; Koppikar, S. J.; Dalvi, M.; Wele, A.; Gaire, V.; Wagh, U. V. Differential growth inhibitory effects of W. somnifera root and E. of f icinalis fruits on CHO cells. Phytother. Res. 2007, 21, 496−499. (61) Sai Ram, M.; Neetu, D.; Yogesh, B.; Anju, B.; Dipti, P.; Pauline, T.; Sharma, S. K.; Sarada, S. K.; Ilavazhagan, G.; Kumar, D.; Selvamurthy, W. Cyto-protective and immunomodulating properties of amla (Emblica of ficinalis) on lymphocytes: an in-vitro study. J. Ethnopharmacol. 2002, 81, 5−10. (62) Sai Ram, M.; Neetu, D.; Dipti, P.; Vandana, M.; Ilavazhagan, G.; Kumar, D.; Selvamurthy, W. Cytoprotective activity of amla (Emblica of f icinalis) against chromium(VI) induced oxidative injury in murine macrophages. Phytother. Res. 2003, 17, 430−433. (63) Suresh, K.; Vasudevan, D. M. Augmentation of murine natural killer cell and antibody dependent cellular cytotoxicity activities by Phyllanthus emblica, a new immunomodulator. J. Ethnopharmacol. 1994, 44, 55−60. (64) Ganju, L.; Karan, D.; Chanda, S.; Srivastava, K. K.; Sawhney, R. C.; Selvamurthy, W. Immunomodulatory effects of agents of plant origin. Biomed. Pharmacother. 2003, 57, 296−300. (65) Sidhu, S.; Pandhi, P.; Malhotra, S.; Vaiphei, K.; Khanduja, K. L. Beneficial effects of Emblica of ficinalis in L-arginine-induced acute pancreatitis in rats. J. Med. Food 2011, 14, 147−155. (66) Muthuraman, A.; Sood, S.; Singla, S. K. The antiinflammatory potential of phenolic compounds from Emblica of f icinalis L in rat. Inflammopharmacology 2010, DOI: 10.1007/s10787-010-0041-9 (online). (67) Nicolis, E.; Lampronti, I.; Dechecchi, M. C.; Borgatti, M.; Tamanini, A.; Bianchi, N.; Bezzerri, V.; Mancini, I.; Giri, M. G.; Rizzotti, P.; Gambari, R.; Cabrini, G. Pyrogallol, an active compound from the medicinal plant Emblica of f icinalis, regulates expression of pro-inflammatory genes in bronchial epithelial cells. Int. Immunopharmacol. 2008, 8, 1672−1680. (68) Srikumar, R.; Jeya Parthasarathy, N. J.; Shankar, E. M.; Manikandan, S.; Vijayakumar, R.; Thangaraj, R.; Vijayananth, K.; Sheela Devi, R.; Rao, U. A. Evaluation of the growth inhibitory activities of Triphala against common bacterial isolates from HIV infected patients. Phytother. Res. 2007, 21, 476−480. (69) Saeed, S.; Tariq, P. Antibacterial activities of Emblica of f icinalis and Coriandrum sativum against Gram negative urinary pathogens. Pak. J. Pharm. Sci. 2007, 20, 32−35. (70) Saini, A.; Sharma, S.; Chhibber, S. Protective efficacy of Emblica of f icinalis against Klebsiella pneumoniae induced pneumonia in mice. Indian J. Med. Res. 2008, 128, 188−193. (71) Rahman, S.; Akbor, M. M.; Howlader, A.; Jabbar, A. Antimicrobial and cytotoxic activity of the alkaloids of amlaki (Emblica of f icinalis). Pak. J. Biol. Sci. 2009, 12, 1152−1155. (72) Perianayagam, J. B.; Narayanan, S.; Gnanasekar, G.; Pandurangan, A.; Raja, S.; Rajagopal, K.; Rajesh, R.; Vijayarajkumar, P.; Vijayakumar, S. G. Evaluation of antidiarrheal potential of Emblica of f icinalis. Pharm. Biol. 2005, 43, 373−377. (73) Mehmood, M. H.; Siddiqia, H. S.; Gilani, A. H. The antidiarrheal and spasmolytic activities of Phyllanthus emblica are mediated through dual blockade of muscarinic receptors and Ca2+ channels. J. Ethnopharmacol. 2011, 133, 856−865. (74) Chen, K. H.; Lin, B. R.; Chien, C. T.; Ho, C. H. Emblica of f icinalis Gaertn. attentuates N-nitrosodiethylamine-induced apopto-

sis, autophagy, and inflammation in rat livers. J. Med. Food 2011, 14, 746−755. (75) Verma, R.; Chakraborty, D. Alterations in DNA, RNA and protein contents in liver and kidney of mice treated with ochratoxin and their amelioration by Emblica of f icinalis aqueous extract. Acta Pol. Pharm. 2008, 65, 3−9. (76) Pramyothin, P.; Samosorn, P.; Poungshompoo, S.; Chaichantipyuth, C. The protective effects of Phyllanthus emblica Linn. extract on ethanol induced rat hepatic injury. J. Ethnopharmacol. 2006, 107, 361−364. (77) Tasduq, S. A.; Kaisar, P.; Gupta, D. K.; Kapahi, B. K.; Maheshwari, H. S.; Jyotsna, S.; Johri, R. K. Protective effect of a 50% hydroalcoholic fruit extract of Emblica of f icinalis against antituberculosis drugs induced liver toxicity. Phytother. Res. 2005, 19, 193−197. (78) Sairam, K.; Rao, Ch. V.; Babu, M. D.; Kumar, K. V.; Agrawal, V. K.; K Goel, R. K. Antiulcerogenic effect of methanolic extract of Emblica of f icinalis: an experimental study. J. Ethnopharmacol. 2002, 82, 1−9. (79) Bandyopadhyay, S. K.; Pakrashi, S. C.; Pakrashi, A. The role of antioxidant activity of Phyllanthus emblica fruits on prevention from indomethacin induced gastric ulcer. J. Ethnopharmacol. 2000, 70, 171− 176. (80) Tasduq, S. A.; Mondhe, D. M.; Gupta, D. K.; Baleshwar, M.; Johri, R. K. Reversal of fibrogenic events in liver by Emblica of f icinalis (fruit), an Indian natural drug. Biol. Pharm. Bull. 2005, 28, 1304−1306. (81) Mir, A. I.; Kumar, B.; Tasduq, S. A.; Gupta, D. K.; Bhardwaj, S.; Johri, R. K. Reversal of hepatotoxin-induced pre-fibrogenic events by Emblica of f icinalis − a histological study. Indian J. Exp. Biol. 2007, 45, 626−629. (82) Chatterjee, A.; Chattopadhyay, S.; Bandyopadhyay, S. K. Biphasic effect of Phyllanthus emblica L. extract on NSAID-induced ulcer: an antioxidative trail weaved with immunomodulatory effect. Evidence Based Complement. Alternat. Med. 2011, DOI: 10.1155/2011/ 146808 (online). (83) Golechha, M.; Bhatia, J.; Ojha, S.; Arya, D. S. Hydroalcoholic extract of Emblica of ficinalis protects against kainic acid-induced status epilepticus in rats: evidence for an antioxidant, anti-inflammatory, and neuroprotective intervention. Pharm. Biol. 2011, 49, 1128−1136. (84) Vasudevan, M.; Parle, M. Memory enhancing activity of Anwala churna (Emblica of f icinalis Gaertn.): an Ayurvedic preparation. Physiol. Behav. 2007, 91, 46−54. (85) Perianayagam, J. B.; Sharma, S. K.; Joseph, A.; Christina, A. J. Evaluation of anti-pyretic and analgesic activity of Emblica of f icinalis Gaertn. J. Ethnopharmacol. 2004, 95, 83−85. (86) Adil, M. D.; Kaiser, P.; Satti, N. K.; Zargar, A. M.; Vishwakarma, R. A.; Tasduq, S. A. Effect of Emblica of f icinalis (fruit) against UVBinduced photo-aging in human skin fibroblasts. J. Ethnopharmacol. 2010, 132, 109−114. (87) Kumar, M. S.; Kirubanandan, S.; Sripriya, R.; Sehgal, P. K. Triphala promotes healing of infected full-thickness dermal wound. J. Surg. Res. 2008, 144, 94−101. (88) Sumitra, M.; Manikandan, P.; Gayathri, V. S.; Mahendran, P.; Suguna, L. Emblica of f icinalis exerts wound healing action through upregulation of collagen and extracellular signal-regulated kinases (ERK1/2). Wound Repair Regen. 2009, 17, 99−107. (89) Del Rio, D.; Rodriguez-Mateos, A.; Spencer, J. P.; Tognolini, M.; Borges, G.; Crozier, A. Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases. Antioxid. Redox Signal. 2013, 18, 1818−1892.

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