An Anthocyanin-Rich Extract of Acai - American Chemical Society

Jan 26, 2016 - Studies with DAF-16/FOXO mutants indicated that some of the antioxidant ... nutritional value.1,2 The beverage is rich in α-tocopherol...
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An anthocyanin-rich extract of Acai (Euterpe precatoria Mart.) increases stress resistance and retards aging related markers in Caenorhabditis elegans. Herbenya Silva Peixoto, Mariana Roxo, Sonja Krstin, Teresa Röhrig, Elke Richling, and Michael Wink J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.5b05812 • Publication Date (Web): 26 Jan 2016 Downloaded from http://pubs.acs.org on January 26, 2016

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Journal of Agricultural and Food Chemistry

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An anthocyanin-rich extract of Acai (Euterpe precatoria Mart.) increases stress resistance and retards aging related markers in Caenorhabditis elegans. Herbenya Peixoto§, Mariana Roxo§, Sonja Krstin§, Teresa Röhrig ¥, Elke Richling¥, Michael Wink§ ⃰ §

Heidelberg University, Institute of Pharmacy and Molecular Biotechnology, INF 364, D-

69120 Heidelberg, Germany ¥

Department of Food Chemistry and Toxicology, Molecular Nutrition, University of

Kaiserslautern, Erwin-Schroedinger-Strasse 52, D-67663 Kaiserslautern, Germany

Corresponding author: Prof. Dr. M. Wink; Email: [email protected]

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Abstract

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Acai fruits (Euterpe precatoria) are rich in antioxidant anthocyanins. Acai consumption is

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believed to have many health benefits; however, relevant detailed scientific investigations are

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limited. The current study aimed to investigate an anthocyanin-rich extract from Euterpe

5

precatoria fruits (AE) with regard to its antioxidant and anti-aging properties using the model

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organism Caenorhabditis elegans. AE can protect the worms against oxidative stress and can

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ameliorate accumulation of reactive oxygen species (ROS) in vivo. The expression of stress

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response genes, such as sod-3::GFP was upregulated while hsp-16::GFP was down-regulated

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after AE treatment. Studies with DAF-16/FOXO mutants indicated that some of the

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antioxidant effects are mediated by this transcription factor. AE can modulate the

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development of age related markers such as the pharyngeal pumping. Despite the apparent

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antioxidant activity, no lifespan prolonging effect was observed.

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Key Words:

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Caenorhabditis elegans, antioxidants, anthocyanins, oxidative stress, aging, Acai

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Introduction

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Acai tree (Euterpe spp.) is a large palm found in the Amazon flood plain. Palm hearts

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and fruits are harvested from this tree. Interest for the fruits, which are traditionally a part of

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the daily diet of indigenous Amazonian people, has increased recently. Acai fruits are

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distributed and consumed in all states of Brazil and are currently being exported to several

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countries. Mixing the fruit’s pulp with iced water produces a drink of a pasty consistency,

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which is famous and much appreciated in Brazil, especially for its nutritional value.

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beverage is rich in α-tocopherol, fibers, lipids, polyphenols (including anthocyanins) and

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mineral ions (such as calcium, magnesium, potassium). 3, 4

1, 2

The

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The fruits which are being used for preparing the beverage come from two species,

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Euterpe oleracea Mart., a clustered trunk palm largely distributed in the Amazon estuary,

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including the northern part of Brazil, French Guyana, Guyana, Suriname, Venezuela and

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Colombia, and Euterpe precatoria Mart., a single trunk palm found in the north of Brazil,

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especially Amazonas, Acre and Rondônia as well as in the Bolivian and Peruvian portion of

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Amazon. 5, 6 The sensorial characteristics of the beverages are similar and they are generally

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referred to as “Acai”. However, the species bear fruits in alternate periods, the E. precatoria

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crop period runs from December to June.7

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Acai has gained the status of “superfruit” together with pomegranate, blueberry, goji

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berry and others exotic fruits. The term superfruit has no official definition by regulatory

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agencies; it is a market expression used since the last decade to refer, especially, to fruits with

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high energetic power, antioxidant capacity, immune boosting and antiaging properties. These

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bioactivities are mainly attributed to the substantial amounts of phytochemicals in the fruits,

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such as polyphenols, polysaccharides and fibers. Cosmetic and toiletry industry are also

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interested in superfruits as a source of natural additives. A large number of products for skin

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and hair care based on superfruit extracts including Acai are available, which claim

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antioxidant, anti-aging and nourishing properties. 8, 9

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A number of biological activities have been reported for Acai fruits from E. oleracea

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including anti-inflammatory, antinociceptive and antioxidant properties. These bioactivities

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are attributed to their high polyphenol content, especially to anthocyanins and flavones.

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Polysaccharides from Acai have been reported to stimulate T cells, thereby playing a

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potential immunomodulatory role in the innate immune response.

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shown to lower the level of cholesterol in the blood in animal models for

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hypercholesterolemia. 17 Udani et al. 18 demonstrated in a non-controlled pilot study, that the

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consumption of Acai reduced the levels of metabolic syndrome markers in overweight adults,

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especially the levels of postprandial glucose, insulin and total cholesterol, and slightly of

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LDL-cholesterol. Stoner et al. 19 showed that the pulp of Acai was able to attenuate tumor

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growth in mice with esophageal cancer. E. precatoria is also rich in polyphenols. The amount

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of anthocyanins is reported to be 50 % higher than in E. oleracea,5 however, studies about its

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biological properties are limited.

16

10-15

Furthermore, Acai was

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Reactive oxygen species (ROS) are normal byproducts of the aerobic metabolism of

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cells responsible for physiological and pathological functions. Among the physiological

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functions cell signaling and antimicrobial activity in the innate immune response are known.

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The pathological functions are due to their capacity to negatively interact with biomolecules

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like proteins, lipids and nucleic acids (causing mutations). ROS imbalance is associated with

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tissue injuries and vascular dysfunction mediated by inflammation, neurodegenerative

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diseases, even cancer and aging. 20, 21

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Considering the dual role of ROS in cells an antioxidant defense system is required to

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neutralize an overproduction of such reactive compounds. The cellular antioxidant defense

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system is composed of antioxidant enzymes and peptides (such as glutathione) endogenously

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produced and also vitamins, trace metals, polyunsaturated fatty acids and polyphenolic

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compounds which are obtained from food sources.

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for antioxidant defence are gradually impaired throughout age resulting in an inability to deal

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with the generation of ROS, which contributes to the aging process and the onset of age-

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related diseases. 24

22, 23

However, the intrinsic mechanisms

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Polyphenols, including anthocyanins, are widely known by their antioxidant capacity

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in vitro and in vivo. 25-27 They are found in plants and are incorporated in human diet through

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consumption of vegetables, fruits and beverages such as tea and juices. There are good

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evidences that dietary polyphenols can modulate oxidative stress and consequently help in the

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prevention or retardation of age-related diseases.

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role of dietary Acai in the modulation of ROS production by neutrophils and in the

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expression of antioxidant genes in the liver of rats. 30

25, 28, 29

Previous works reported a positive

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In the current study a methanol/water extract from E. precatoria fruits was

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investigated with regard to its antioxidant and anti-aging properties using the nematode

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Caenorhabditis elegans, a model organism widely used in this context.

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antioxidant activity the capacity of the extract to protect the nematodes against acute

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oxidative stress was investigated, as well as the influence on reactive oxygen species (ROS)

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accumulation in vivo. The expression of stress response genes, such as sod-3::GFP and hsp-

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16.2::GFP was also assessed as well as the participation of the DAF-16/FOXO transcription

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factor. In order to study a potential anti-aging activity, aging markers such as the

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autofluorescent pigment in C. elegans gut granules and the pharyngeal pumping rate were

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analyzed. Fertility rate, body length and lifespan of the nematodes were also assessed.

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With regard to

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Methods

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Extraction and Plant Material

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A hydroalcoholic extract was obtained from ripe E. precatoria fruits. The fruits, with

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origin in Codajás-AM (Brazil), were purchased in a local market in Manaus-AM (Brazil) in

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February, during the crop period for this species. The whole fruits were submitted to

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hydroalcoholic extraction (80 % (v/v, methanol/water) acidified with citric acid 0.15 %) and

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then concentrated in vacuum at 37 ºC using a rotavapor. Finally, the extract was submitted to

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a spray-drying (180 °C inlet temperature and 100 °C outlet temperature). The final product

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was stored at room temperature (25 ºC) in amber glasses.

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Characterization of Anthocyanins

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The anthocyanin content of the extract was characterized and quantified by HPLC-

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UV/VIS. An aliquot of the sample was diluted in solvent A (87 % water / 3 % acetonitrile /

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10 % formic acid (v/v/v)), mixed (3 min), centrifuged (5.000 rpm, 20 min, 20 °C) and filtered

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using Millipore membrane (0.45 µm PVDF). The internal standard (IS), delphinidin-3 5-

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diglucoside (del-3.5-di-glc) 100 µg/ml, was added to the aliquots which were analysed in

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duplicate. A calibration curve was established using cyanidin-3-glucoside (cy-3-glc) 0.1-10

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µg/ml. Briefly, the analyses were conducted with a Jasco HPLC-UV system equipped with a

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Jasco PU-2080 intelligent HPLC pump, a Jasco LG-2080–02 ternary gradient unit, a Jasco

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UV-2075 plus intelligent UV/VIS detector, a Jasco DG-2080–53 3-line-degasser, and an AS-

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2055 plus intelligent sampler (Jasco, Gross-Umstadt, Germany). The samples were eluted

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according to the following elution gradients with solvent A (see above) and solvent B (40 %

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water / 50 % acetonitrile / 10 % formic acid): between 0 to 1 min, 2 % B; between 1 and 20

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min, 2 %–14 % B; 20–40 min held at 14 % B; 40–50 min increased to 15 % B; 50–55 min

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increased to 19 % B; 55–65 min raised to 20 % B, 65 – 65.1 min, from 20-99 % B; 65.1 – 70

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min, constant 99 % B; 70.1–110 min re-equilibrated with 2 % solvent B. 34 The flow rate was

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0.5 mL/min, the detection wavelength was 520 nm, and the injection volume was 20 µl at

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room temperature.

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DPPH

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The antioxidant activity of Acai extract (AE) was assessed by measuring the decrease

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in the absorbance of the stable free radical DPPH (2,2-diphenyl-1-picrylhydrazyl) (Sigma-

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Aldrich GmbH, Steinheim, Germany) as described by Blois

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microplate analysis. Briefly, 100 µl of DPPH 200 µM methanol solution were added to 100

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µl of sample or standard. The standard, epigallocatechin gallate (EGCG) (Sigma-Aldrich

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GmbH, Steinheim, Germany), and the sample were both diluted in methanol. The reaction

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ran protected from light at room temperature (25 ºC) for 30 min. The absorbance was

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measured at 517 nm in a microplate reader (Tecan Group Ltd., Männedorf, Switzerland). The

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ability to scavenge the DPPH radicals was calculated using the following equation:

35

, adapted to a 96-wells

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DPPH scavenging effect (%) = [(A0 –A1)/A0]×100

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Where A0 means the absorbance of the control reaction and A1 is the absorbance in

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the presence of AE. All measurements were performed in triplicate. The EC50 value was

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estimated by sigmoid non-linear regression using GraphPad Prism version 6.00 for Windows

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(GraphPad Software, La Jolla, CA, USA) adequate software and is presented in µg/ml.

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SPF in vitro The sun protection factor (SPF) was determined spectrophotometrically following the 36

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method described by Mansur as cited in Mishra.

Briefly, AE 0.01 % hydroalcoholic

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solution (ethanol 40 %) was scanned with a Jasco V-630 UV-VIS Spectrophotometer (Jasco,

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Gross-Umstadt, Germany) between 290-320 nm, at intervals of 5 mm using a HELL 6040-

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UV quartz cuvette (Hellma, Müllheim, Germany). The SPF was calculated using the

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following equation: 

   = .  .  

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Where CF = correction factor (10), EE (λ) = erythmogenic effect of radiation with

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wavelength λ, Abs (λ) = spectrophotometric absorbance values at wavelength λ. The values

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of EE (λ) x I are constants previously determined by Sayre. 37

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Total Phenolic Content

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The assay was carried out according to the Folin-Ciocalteu method with minor modifications

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to 96-well microplate analysis. Briefly, 100 µl of Folin-Ciocalteu reagent (Merck, Darmstadt,

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Germany) were added to 20 µl of sample; 5 min later 80 µl of sodium carbonate (7.5 %

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solution) were also added. Gallic acid was used as standard. The reaction ran in dark, at room

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temperature (25 ºC) for 2 h. Then the absorbance was measured at 750 nm. The sample and

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standard were dissolved in methanol. All measurements were carried out in triplicate and at

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least three times. The phenolic content is expressed as gallic acid equivalents (GAE/mg of

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sample).

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C. elegans – Strains and Maintenance

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C. elegans strains (N2 (wt), TK-22 (mev-1(kn1)III), TJ375 (gpIs1[hsp-16-2::GFP]),

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CF1553 (muls84[pAD76(sod-3::GFP)]), TJ356 (zIs356 [daf-16p::daf-16a/b::GFP+rol-6]),

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CF1038 (daf-16(mu86)I), GR1307 (daf-16(mgDf50)I), BA17 (fem-1(hc17)IV) were

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purchased from the Caenorhabditis Genetics Center (CGC, University of Minnesota,

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Minneapolis, USA) and cultured in NGM agar medium, seeded with E. coli OP50 as food

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source (CGC, University of Minnesota, Minneapolis, USA). The worms were incubated at

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20°C, except when mentioned. For assays that demand liquid medium the S-medium was

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employed which was complemented with E. coli OP50 (DO600=1.0). Synchronous

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populations were obtained by treating the gravid worms during 5 min with 5 M NaOH and

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5% NaOCl in the ratio 3:1, for lysis and decontamination. The lysate was pelleted by

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centrifugation (1200 rpm, 1 min). The eggs were separated from the pellet by density gradient

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using sucrose solution (60 % w/v) and water in the ratio 1:1, followed by centrifugation

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(1200 rpm, 4 min). The upper layer, in which the eggs float, was collected and transferred to

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a fresh tube with sterile water (1:3) then, submitted to a last centrifugation step (1200 rpm, 1

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min) to pellet the eggs and wash out the sucrose. The eggs were allowed to hatch in M9

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buffer. 38

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Survival Assay Under Oxidative Stress

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Synchronized wild type (N2 grown in S-medium) and transgenic worms (CF1038,

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GR1307 grown in S-medium) at L1 larval stage were sorted into populations and treated with

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AE for 48 h, except the control group. Each group contained 75 individuals. Thereafter, all

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the groups were exposed to the pro-oxidant juglone (5-hydroxy-1,4-naphthoquinone) (Sigma-

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Aldrich GmbH, Steinheim, Germany) 80 µM for 24 h. Dead and live worms were counted

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afterwards. The worms were considered dead when they did not respond to a gentle touch

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with a platinum wire on their bodies.39 The survival rate is presented as mean of three

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independent runs (mean ± SEM) and compared by one-way ANOVA followed by Bonferroni

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(post-hoc) using Graphpad Prism for windows, Version 6.01.

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Intracellular ROS Accumulation

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Synchronized worms (N2 grown in S-medium) at L1 larval stage were sorted into

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populations and treated with AE for 48 h, except the control group. After treatment, the

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worms were washed with M9 buffer and pelleted by centrifugation. The pellet was

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reconstituted in 1 ml of 50 µM CM-H2DCFDA solution (Fluka Chemie GmbH, Buchs,

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Switzerland) and incubated, protected from the light, for 1 h at 20 °C. To remove an excess

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of the dye, the worms were washed once more with M9 buffer and then mounted on a glass

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slide with a drop of 10 mM sodium azide (AppliChem GmbH, Darmstadt, Germany) for

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paralysis. Using the BIOREVO BZ-9000 fluorescence microscope (Keyence Deutschland

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GmbH, Neu-Isenburg, Germany) equipped with a mercury lamp, the slides were analyzed

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(λEx 480/20 nm; λEm 510/38 nm) and photographed. Images were taken from at least 30

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worms at constant exposure time using a 10X objective lens. The relative fluorescence of the

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whole body was determined densitometrically using Image J version 1.48 (National Institutes

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of Health, MD, USA) software. The results are presented as mean fluorescence intensity of

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three independent runs (mean ± SEM) and compared by one-way ANOVA followed by

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Bonferroni (post-hoc).

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Quantification of hsp-16.2::GFP Expression

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Synchronized worms (transgenic strain TJ375 grown in S-medium) at larval stage L4

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were sorted into populations and treated with AE for 48 h, except the control group. Then all

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the groups were exposed to 20 µM juglone for 24 h. After juglone incubation, the worms

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were analysed as described before.

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Quantification of sod-3::GFP Expression

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Synchronized cultures of transgenic C. elegans strain CF1553 (L1 larvae, grown in S

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media) carrying a sod-3::GFP fusion protein as reporter were treated with AE for 72 h, except

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the control group, and then submitted to fluorescence microscopy as described above.

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Quantification of DAF-16::GFP Expression

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Synchronized worms (transgenic strain TJ356 grown in S-medium) at larval stage L1

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were sorted into populations and treated with AE for 72 h, except the control group. The

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analysis by fluorescence microcopy was carried out as described above.

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Quantification of Autofluorescent Pigment in C. elegans

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Synchronized wild-type worms (N2 grown in S-medium) were sorted into

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populations at day 1 of adulthood and treated during 5 days with AE, except the control

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group. The analysis by fluorescence microcopy (λEx 360/20 nm; λEm 460/38 nm) was carried

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out as described above.

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Journal of Agricultural and Food Chemistry

Brood Size and Body Length

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Synchronized N2 worms from larval stage L4 were sorted and placed one by one on

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individual NGM agar plates. E. coli OP50 lawn was provided as food source. In the treatment

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group the bacterial lawn was supplemented with AE. The adult worms were transferred daily

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to fresh medium to separate them from their progeny. The eggs were counted every day for 5

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days using a dissecting microscope.

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compared by two-way ANOVA followed by Bonferroni (post-hoc). To measure the body

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length, the worms (at day 1 of adulthood) were mounted on a glass slide, paralyzed with a

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drop of 10 mM sodium azide and analyzed by bright field microscopy. Images were taken

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from at least 30 worms using a 10X objective lens. The body length was measured using the

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software BZ-II Analyzer (Keyence Corporation). The results are presented as body length in

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µm (mean ± SEM) and compared by one-way ANOVA followed by Bonferroni (post-hoc).

33

The result is presented as mean brood size and

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Pharyngeal Pumping Rate

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Age synchronized worms from N2 (wt) strain, at day 1 of adulthood, were sorted into

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populations and placed on NGM agar plates, containing E. coli OP50 lawn as a food source.

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In the treatment group the bacterial lawn was supplemented with AE. The adult worms,

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during the reproductive period, were transferred every second day to fresh medium to

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separate them from their progeny. After egg laying had ceased the worms were transferred to

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fresh medium, always on the day before the analyses of pumping activities. On day 5, 10, 12

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and 15 of adulthood the pumping frequency of the terminal pharyngeal bulb was counted

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using a dissection microscope. Each single worm was observed for 60 sec and the pumping

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frequency was recorded. Each group had a minimum of 10 worms. The pumping frequency

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was scored when the worms were crawling on the bacterial lawn. 33, 40 The result is presented

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as pumps min-1 (mean ± SEM) and compared by two-way ANOVA followed by Bonferroni

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(post-hoc).

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Longevity Assay

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Synchronized worms (N2 and TK-22, grown in S-medium) at day 1 of adulthood were

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sorted into populations of 90 individuals each and treated with AE, except the control group.

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During the reproductive period they were daily transferred to fresh medium to separate the

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adults under study from their progeny, thereafter the transfer was carried out every second

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day. The worms were counted during the transfer to fresh medium. The worms with internally

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hatched progeny or extruded gonads were discarded from the assay. Worms that no longer

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responded to a gentle touch with the platinum wire were scored as dead and excluded from

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the plates. The results are presented as percentage of survival and the statistical significance

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determined by Log-rank (Mantel-Cox) tests followed by Gehan-Breslow-Wilcoxon Test.

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Results and Discussion

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An HPLC-UV/VIS analysis revealed the presence of three anthocyanins in the

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methanol/water extract from E. precatoria fruits, which were identified as cyanidin-3-

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rutinoside (corresponding to 89.44 % of the anthocyanins) and traces of cyanidin-3-glucoside

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and peonidin-3-rutinoside (Table 01). Our analysis thus agrees with literature data indicating

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that cyanidin-3-rutinoside is the main anthocyanin of E. precatoria fruits. 5

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The polyphenol rich AE exhibits powerful antioxidant activity in vitro. When tested in

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the DPPH assay, AE effectively scavenged the radical (EC50= 3.8 µg AE ml-1). These values

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are in a similar range as of known antioxidants, such as EGCG or ascorbic acid (Table 02). In

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accordance with the antioxidant activities, a high phenolic content of 205 GAE mg-1 was

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determined by the Folin-Ciocalteu method.

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Also in vivo data confirm the antioxidant activity of AE as it can effectively protect C.

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elegans against oxidative stress and reduce endogenous ROS levels. The extract can attenuate

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the deleterious effects of juglone, a secondary metabolite of Juglans regia, which can

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increase the formation of free radicals in vivo. After 80 µM juglone exposure, the survival

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rate of the worms pre-treated with 200 µg.ml-1 of AE was significantly higher (up to 86.34 ±

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3.08 %) when compared to the untreated control group (38.50 ± 1.50 %), (adjusted P-value of

286

0.0007). (Figure 1a).

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To assess the effect of AE on ROS accumulation the cell permeant reagent H2DCF-

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DA (2’,7’- dichlorofluorescin diacetate) was employed. This compound becomes

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deacetylated by intracellular esterases and remains inside the cells. Inside cells, H2DCF-DA is

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subjected to oxidation in the presence of intracellular ROS. The oxidized compound emits

291

fluorescence, whose intensity correlates with intracellular ROS levels.

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fluorescence intensities were observed among nematodes treated with AE in relation to the

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untreated control group (Figure 1b). The treatment with 200 µg.ml-1 AE decreased by 58.1%

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the intracellular ROS accumulation (adjusted P-value < 0.0001). This effect showed to be

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concentration-dependent, indicating that the antioxidants have been absorbed by the worms

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and are thus bioavailable.

41

Significant lower

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More evidence that AE can attenuate oxidative stress was obtained by quantifying the

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expression of heat shock proteins (HSP) in the mutant strain TJ375, which has a hsp-16.2

299

promoter fused with a GFP reporter. HSPs represent a family of proteins found in nearly all

300

living organisms that exhibits among others chaperone activity. HSP expression is induced

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mainly by heat shock or oxidative stress.

42, 43

In C. elegans the HSP16.2, categorized as

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small HSP, is not expressed unless the organism is facing pernicious environmental

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conditions. These conditions can be high temperature or the presence of oxidants like juglone

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that are directly associated with protein damage.

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with 20 µM juglone the hsp-16.2 is expressed as seen through the increased fluorescence

306

intensity. Among the groups pre-treated with AE the fluorescence intensity is significantly

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lower compared to the untreated control group under the same conditions (Figure 2a). Thus,

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as lower fluorescence intensity correlates with lower expression of hsp-16.2, this data

309

indicates that AE is able to attenuate oxidative stress in C. elegans. The most pronounced

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effect was observed at a concentration of 200 µg.ml-1 AE that decreased by 59.06 % the

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fluorescence intensity in comparison to the untreated control group (adjusted P-value

312

0.0001). The ability to suppress the expression of hsp-16.2 under induced oxidative stress

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was also described for a green tea extract and its main constituent EGCG. 45, 46

44

After incubation of the TJ375 mutants

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Antioxidant balance inside the cells also requires the participation of enzymes with

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the ability to neutralize ROS. SOD-3 is a mitochondrial enzyme with O2˙-scavenging activity.

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SOD-3 is important for C. elegans to maintain a balance of ROS; its expression can be

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influenced by antioxidants. 47, 48 Using the mutant strain CF1553, which has a sod-3 promoter

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fused with a GFP reporter, a higher expression was detected among AE treated worms in

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comparison with untreated control worms (Figure 2b). 200 µg.ml-1 AE increased by 67.65 %

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the expression of sod-3::GFP which correlates with the measured fluorescence intensity

321

(adjusted P-value < 0.0001). EGCG was also shown to up-regulate sod-3::GFP expression. 49

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These findings indicate that AE performs its antioxidant activity not only by

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scavenging radicals but additionally by modulation of the expression of stress response genes

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such as sod-3 and hsp-16.2.

325

DAF-16/FOXO is the main transcription factor involved in the regulation of stress

326

response genes. Under normal conditions, DAF-16/FOXO remains inactive in the cytosol.

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However, environmental conditions and stress or certain ligands can stimulate its

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translocation to the nucleus, where it influences the expression of a variety of genes involved

329

in stress response, metabolism and longevity.

330

antioxidant effects via the DAF-16/FOXO pathway, survival assays were carried out with a

331

daf-16 loss-of-function mutant (CF1038) and a daf-16 null mutant (GR1307). In both strains,

332

AE failed to increase the survival rate (Figure 3), in contrast to results obtained with N2 (wt)

333

worms (Figure 1a). When AE was tested in the mutant strain TJ356, which has a daf-16 fused

334

with a GFP reporter, a higher percentage of worms exhibited a nuclear location pattern of

335

DAF-16::GFP than the untreated control group. The worms treated with 200 µg.ml-1 AE

336

showed a highly significant fraction of 64.00 ± 4 % DAF-16 nuclear localisation compared

337

with 8,5 ± 4,5 % observed among the untreated worms (adjusted P-value < 0.0001). These

338

findings strongly suggest that AE enhances stress resistance in C. elegans via the DAF-

339

16/FOXO pathway. An anthocyanin-rich extract of purple wheat was also shown to activate

340

DAF-16/FOXO in C. elegans. 48

50, 51

To assess whether AE also exerts its

341

C. elegans is a widely used model to analyze longevity as its lifespan is short, usually

342

around 15 d. Using N2 (wt) and TK-22 nematodes we have analyzed whether AE can

343

influence longevity as observed with other polyphenols.

344

performance regarding its antioxidant capacity in vivo, AE did not show any lifespan

345

prolonging effects (Table 3).

346

46, 52, 53

Despite of the good

In mammals, aging is accompanied by a decline in muscle function, accumulation of 33, 54

347

age pigments (lipofuscin) and impaired proteostasis.

These processes are also active in

348

C. elegans which can thus be used as model organism in aging studies. We employed the

349

wildtype N2 worms to study the influence of AE on aging. Regarding the autofluorescent

350

pigment, worms treated with AE showed a lower level of the autofluorescent pigment when

351

measured at the day 5 of adulthood (Figure 4a). Compared to the untreated control group, the

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treatment with 200 µg.ml-1 AE decreased the level of the autofluorescent pigment by 51.09

353

%. Coburn55 demonstrated that the inhibition of the pathway that generates the

354

autofluorescent pigment can protect animals against stress-induced death. The capacity of

355

polyphenolic compounds to decrease the autofluorescent pigment level had already been

356

reported for EGCG, quercetin, caffeic acid and kaempferol. 45, 56, 57

357

Muscle activity was estimated by measuring the pharyngeal pumping rate at different

358

intervals of adulthood. AE treated worms showed a better performance when compared with

359

untreated control group throughout the entire period (Figure 4b). At the day 15, the

360

pharyngeal pumping rate of the worms treated with 300 µg.ml-1 AE was 173 % higher than

361

the rate observed in the untreated control group (adjusted P-value < 0.0001). This data

362

implies that a dietary restriction (DR) effect can be ruled out; hence the capacity of the

363

worms to feed on E. coli OP50 was not compromised.

364

Brood size and body length were not influenced by AE treatment (Table 4) indicating

365

that AE did not impair the fertility rate nor body development (e.g., via DR). These

366

parameters are mentioned in the literature as toxicity markers. 58, 59

367

In summary, an anthocyanin-rich extract of Euterpe precatoria (Acai) enhanced

368

oxidative stress resistance in C. elegans by promoting DAF-16/FOXO translocation, thus

369

modulating the expression of stress response genes. Worms under treatment showed lower

370

ROS accumulation as well as a higher survival rate when challenged by the pro-oxidant

371

juglone inducing oxidative stress. Our data indicate that Acai also has beneficial effect on the

372

aging process, evidenced by its capacity to ameliorate the age-related decrease in pharyngeal

373

pumping rate, a marker that correlates with the human age-related sarcopenia. The level of

374

the autofluorescent pigment was also attenuated by Acai treatment. However, a lifespan

375

prolonging effect was not noticed. Additionally, the Acai extract exhibits UV protective

376

properties, a SPF of 8 was demonstrated for a solution 0.01 %; this feature might correlate

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with the high polyphenolic content of AE. These solar protective properties might support the

378

use of Acai in cosmetic formulations for hair and skin care. In conclusion, the Acai extract

379

demonstrated antioxidant and anti-aging activities in C. elegans which might support certain

380

nutraceutical claims. Further studies are needed to clarify to what extent the results can be

381

exploited in human health and wellness, including in vivo tests with more complex model

382

organisms.

383

384

Acknowledgements. HP gratefully acknowledge CNPq (National Council of Scientific and

385

Technological Development, Brazil) for the PhD scholarship.

386

387

Conflict of interest: “The authors declare no competing financial interest.”

388 389 390 391 392 393 394 395 396 397 398 399 400

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References

407 408

(1) de Farias Neto, J. T.; Vasconcelos, M. A. M.; da Silva, F. C. F. Cultivo, processamento, padronização e comercialização do açaí na Amazônia. FRUTAL. 2010, 60120, 002.

409 410 411

(2) Pedrozo, E. Á.; Silva, T. N. d.; Sato, S. A. d. S.; Oliveira, N. D. A. Produtos Florestais Não Madeiráveis (PFNMS): as Filières do Açaí e da Castanha da Amazônia. RARA. 2011, 3, 88-112.

412 413

(3) Rogez, H. Açaí: preparo, composição e melhoramento da conservação, edition no. 1; EDUFPA: Brazil, 2000.

414 415 416 417

(4) Maria do Socorro, M. R.; Pérez-Jiménez, J.; Arranz, S.; Alves, R. E.; de Brito, E. S.; Oliveira, M. S.; Saura-Calixto, F. Açaí (Euterpe oleraceae)‘BRS Pará’: A tropical fruit source of antioxidant dietary fiber and high antioxidant capacity oil. Food Res. Int. 2011, 44, 2100-2106.

418 419 420

(5) Pacheco-Palencia, L. A.; Duncan, C. E.; Talcott, S. T. Phytochemical composition and thermal stability of two commercial açai species, Euterpe oleracea and Euterpe precatoria. Food Chem. 2009, 115, 1199-1205.

421 422 423

(6) Bussmann, R. W.; Zambrana, N. Y. P. Facing global markets-usage changes in Western Amazonian plants: the example of Euterpe precatoria Mart. and E. oleracea Mart. Acta Soc. Bot. Pol. 2012, 81.

424 425

(7) SFG. Guia de espécies PFNM. Guia de espécie e de campo Açaí. URL (http://www.florestal.gov.br/guia-de-especies-pfnm/view-category) (January 12, 2016).

426 427 428

(8) de Lima Yamaguchi, K. K.; Pereira, L. F. R.; Lamarão, C. V.; Lima, E. S.; da VeigaJunior, V. F. Amazon acai: Chemistry and biological activities: A review. Food Chem. 2015, 179, 137-151.

429 430 431

(9) Lal, G. G. Processing of Beverages for the Heath Food Market Consumer. In Nutraceutical and Functional Food Processing Technology, edition no. 1; Boye, J. I., Ed.; Wiley-Blackwell: UK, 2015; pp. 189-210.

432 433 434

(10) Lichtenthäler, R.; Rodrigues, R. B.; Maia, J. G. S.; Papagiannopoulos, M.; Fabricius, H.; Marx, F. Total oxidant scavenging capacities of Euterpe oleracea Mart.(Acai) fruits. Int. J. Food Sci. Nutr. 2005, 56, 53-64.

ACS Paragon Plus Environment

Page 20 of 31

Page 21 of 31

Journal of Agricultural and Food Chemistry

435 436 437 438

(11) Mertens-Talcott, S. U.; Rios, J.; Jilma-Stohlawetz, P.; Pacheco-Palencia, L. A.; Meibohm, B.; Talcott, S. T.; Derendorf, H. Pharmacokinetics of anthocyanins and antioxidant effects after the consumption of anthocyanin-rich acai juice and pulp (Euterpe oleracea Mart.) in human healthy volunteers. J. Agric. Food Chem. 2008, 56, 7796-7802.

439 440 441

(12) Kang, J.; Xie, C.; Li, Z.; Nagarajan, S.; Schauss, A. G.; Wu, T.; Wu, X. Flavonoids from acai (Euterpe oleracea Mart.) pulp and their antioxidant and anti-inflammatory activities. Food Chem. 2011, 128, 152-157.

442 443 444 445

(13) Kang, J.; Thakali, K. M.; Xie, C.; Kondo, M.; Tong, Y.; Ou, B.; Jensen, G.; Medina, M. B.; Schauss, A. G.; Wu, X. Bioactivities of açaí (Euterpe precatoria Mart.) fruit pulp, superior antioxidant and anti-inflammatory properties to Euterpe oleracea Mart. Food Chem. 2012, 133, 671-677.

446 447 448

(14) Favacho, H. A.; Oliveira, B. R.; Santos, K. C.; Medeiros, B. J.; Sousa, P. J.; Perazzo, F. F.; Carvalho, J. C. T. Anti-inflammatory and antinociceptive activities of Euterpe oleracea Mart., Arecaceae, oil. Rev. Bras. Farmacogn. 2011, 21, 105-114.

449 450 451 452

(15) Schauss, A. G.; Wu, X.; Prior, R. L.; Ou, B.; Huang, D.; Owens, J.; Agarwal, A.; Jensen, G. S.; Hart, A. N.; Shanbrom, E. Antioxidant capacity and other bioactivities of the freezedried Amazonian palm berry, Euterpe oleraceae Mart. (acai). J. Agric. Food Chem. 2006, 54, 8604-8610.

453 454 455

(16) Holderness, J.; Schepetkin, I. A.; Freedman, B.; Kirpotina, L. N.; Quinn, M. T.; Hedges, J. F.; Jutila, M. A. Polysaccharides isolated from Acai fruit induce innate immune responses. PLoS One. 2011, 6, e17301.

456 457 458

(17) de Souza, M. O.; Silva, M.; Silva, M. E.; de Paula Oliveira, R.; Pedrosa, M. L. Diet supplementation with acai (Euterpe oleracea Mart.) pulp improves biomarkers of oxidative stress and the serum lipid profile in rats. Nutrition. 2010, 26, 804-810.

459 460 461

(18) Udani, J. K.; Singh, B. B.; Singh, V. J.; Barrett, M. L. Effects of Acai (Euterpe oleracea Mart.) berry preparation on metabolic parameters in a healthy overweight population: A pilot study. Nutr. J. 2011, 10, 45.

462 463 464

(19) Stoner, G. D.; Wang, L.-S.; Seguin, C.; Rocha, C.; Stoner, K.; Chiu, S.; Kinghorn, A. D. Multiple berry types prevent N-nitrosomethylbenzylamine-induced esophageal cancer in rats. Pharm. Res. 2010, 27, 1138-1145.

465 466

(20) Mittal, M.; Siddiqui, M. R.; Tran, K.; Reddy, S. P.; Malik, A. B. Reactive oxygen species in inflammation and tissue injury. Antioxid. Redox Signaling. 2014, 20, 1126-1167.

467 468

(21) Rahman, K. Studies on free radicals, antioxidants, and co-factors. Clin. Interventions Aging. 2007, 2, 219.

469 470

(22) Pham-Huy, L. A.; He, H.; Pham-Huy, C. Free radicals, antioxidants in disease and health. Int. J. Biomed. Sci. 2008, 4, 89.

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

471 472

(23) del Valle, L. G. Oxidative stress in aging: Theoretical outcomes and clinical evidences in humans. Biomed. Aging Pathol. 2011, 1, 1-7.

473 474

(24) Raha, S.; Robinson, B. H. Mitochondria, oxygen free radicals, disease and ageing. Trends Biochem. Sci. 2000, 25, 502-508.

475 476

(25) Scalbert, A.; Johnson, I. T.; Saltmarsh, M. Polyphenols: antioxidants and beyond. Am. J. Clin. Nutr. 2005, 81, 215S-217S.

477 478 479

(26) Choi, D.Y.; Lee, Y.J.; Hong, J. T.; Lee, H.J. Antioxidant properties of natural polyphenols and their therapeutic potentials for Alzheimer's disease. Brain Res. Bull. 2012, 87, 144-153.

480 481

(27) Perron, N. R.; Brumaghim, J. L. A review of the antioxidant mechanisms of polyphenol compounds related to iron binding. Cell Biochem. Biophys. 2009, 53, 75-100.

482 483

(28) van Wyk, B. E.; Wink, M. Phytomedicines, Herbal Drugs, and Poisons, edition no. 1. University of Chicago Press: Chicago, IL, 2015.

484 485

(29) Wink, M. Modes of action of herbal medicines and plant secondary metabolites. Medicines. 2015, 2, 251-286.

486 487 488

(30) da Costa Guerra, J. F.; de Brito Magalhães, C. L.; Costa, D. C.; Silva, M. E.; Pedrosa, M. L. Dietary açai modulates ROS production by neutrophils and gene expression of liver antioxidant enzymes in rats. J. Clin. Biochem. Nutr. 2011, 49(3), 188.

489 490

(31) Olsen, A.; Vantipalli, M. C.; Lithgow, G. J. Using Caenorhabditis elegans as a model for aging and age related diseases. Ann. N. Y. Acad. Sci. 2006, 1067, 120-128.

491 492 493

(32) Kregel, K. C.; Zhang, H. J. An integrated view of oxidative stress in aging: basic mechanisms, functional effects, and pathological considerations. Am. J. Physiol. Regul. Integr. Comp. Physiol. 2007, 292, R18-R36.

494 495

(33) Rothman, J. H.; Singson, A. Caenorhabditis elegans: cell biology and physiology. Academic Press. 2012; Vol. 107.

496 497 498

(34) Müller, D.; Schantz, M.; Richling, E. High performance liquid chromatography analysis of anthocyanins in bilberries (Vaccinium myrtillus L.), blueberries (Vaccinium corymbosum L.), and corresponding juices. J. Food Sci. 2012, 77, C340-C345.

499 500

(35) Blois, M. S. Antioxidant determinations by the use of a stable free radical. Nature. 1958, 181, 1199-1200

501 502 503

(36) Mishra, A.; Mishra, A.; Chattopadhyay, P. Assessment of in vitro sun protection factor of Calendula officinalis L.(asteraceae) essential oil formulation. J. Young Pharm. 2012, 4, 17-21.

504 505

(37) Sayre, R. M.; Agin, P. P.; LeVee, G. J.; Marlowe, E. A comparison of in vivo and in vitro testing of sunscreening formulas. Photochem. Photobiol. 1979, 29, 559-566.

ACS Paragon Plus Environment

Page 22 of 31

Page 23 of 31

Journal of Agricultural and Food Chemistry

506 507 508

(38) Stiernagle, T. Maintenance of C. elegans (February 11, 2006). In WormBook; The C. elegans Research Community, Ed.; WormBook, doi/10.1895/wormbook.1.7.1, http://www.wormbook.org.

509 510

(39) Hart, Anne C., Ed. Behavior (July 3, 2006). In WormBook; The C. elegans Research Community Ed.; WormBook, doi/10.1895/wormbook.1.87.1, http://www.wormbook.org.

511 512 513

(40) Huang, C.; Xiong, C.; Kornfeld, K. Measurements of age-related changes of physiological processes that predict lifespan of Caenorhabditis elegans. Proc. Natl. Acad. Sci. U. S. A. 2004, 101, 8084-8089.

514 515 516

(41) Eruslanov, E.; Kusmartsev, S. Identification of ROS using oxidized DCFDA and flowcytometry. In Advanced Protocols in Oxidative Stress II; Armstrong, D., Ed.; Humana Press: Totowa, NJ, 2010; pp 57-72.

517 518

(42) Swindell, W. R. Heat shock proteins in long-lived worms and mice with insulin/insulinlike signaling mutations. Aging. 2009, 1, 573.

519 520 521

(43) Strayer, A.; Wu, Z.; Christen, Y.; Link, C. D.; Luo, Y. Expression of the small heatshock protein Hsp16-2 in Caenorhabditis elegans is suppressed by Ginkgo biloba extract EGb 761. FASEB J. 2003, 17, 2305-2307.

522 523 524

(44) Heidler, T.; Hartwig, K.; Daniel, H.; Wenzel, U. Caenorhabditis elegans lifespan extension caused by treatment with an orally active ROS-generator is dependent on DAF-16 and SIR-2.1. Biogerontology. 2010, 11, 183-195.

525 526 527

(45) Abbas, S.; Wink, M. Epigallocatechin gallate inhibits beta amyloid oligomerization in Caenorhabditis elegans and affects the daf-2/insulin-like signaling pathway. Phytomedicine. 2010, 17, 902-909.

528 529

(46) Su, S.; Wink, M. Natural lignans from Arctium lappa as antiaging agents in Caenorhabditis elegans. Phytochemistry. 2015, 117, 340-350.

530 531

(47) Zhou, K. I.; Pincus, Z.; Slack, F. J. Longevity and stress in Caenorhabditis elegans. Aging (Albany NY). 2011, 3, 733.

532 533

(48) Shi, Y.-C.; Yu, C.-W.; Liao, V.; Pan, T.-M. Monascus-fermented Dioscorea enhances oxidative stress resistance via DAF-16/FOXO in Caenorhabditis elegans. PloS One. 2012, 7.

534 535

(49) Zhang, L.; Jie, G.; Zhang, J.; Zhao, B. Significant longevity-extending effects of EGCG on Caenorhabditis elegans under stress. Free Radic. Biol. Med. 2009, 46, 414-421.

536 537

(50) Braeckman, B. P.; Vanfleteren, J. R. Genetic control of longevity in C. elegans. Exp. Gerontol. 2007, 42, 90-98.

538 539

(51) Mukhopadhyay, A.; Oh, S. W.; Tissenbaum, H. A. Worming pathways to and from DAF-16/FOXO. Exp. Gerontol. 2006, 41, 928-934.

ACS Paragon Plus Environment

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540 541

(52) Abbas, S.; Wink, M. Green tea extract induces the resistance of Caenorhabditis elegans against oxidative stress. Antioxidants. 2014, 3, 129-143.

542 543 544

(53) Chen, W.; Müller, D.; Richling, E.; Wink, M. Anthocyanin-rich purple wheat prolongs the life span of Caenorhabditis elegans probably by activating the DAF-16/FOXO transcription factor. J. Agric. Food Chem. 2013, 61, 3047-3053.

545 546 547

(54) Herndon, L. A.; Schmeissner, P. J.; Dudaronek, J. M.; Brown, P. A.; Listner, K. M.; Sakano, Y.; Paupard, M. C.; Hall, D. H.; Driscoll, M. Stochastic and genetic factors influence tissue-specific decline in ageing C. elegans. Nature. 2002, 419, 808-814.

548 549 550 551 552

(55) Coburn, C.; Allman, E.; Mahanti, P.; Benedetto, A.; Cabreiro, F.; Pincus, Z.; Matthijssens, F.; Araiz, C.; Mandel, A.; Vlachos, M.; Edwards, S. A.; Fischer, G.; Davidson, A.; Pryor, R. E.; Stevens, A.; Slack, F. J.; Tavernarakis N.; Braeckman, B. P.; Schroeder, F. C.; Nehrke, K.; Gems, D. Anthranilate fluorescence marks a calcium-propagated necrotic wave that promotes organismal death in C. elegans. PLoS Biol. 2013, 11(7), e1001613.

553 554 555

(56) Pietsch, K.; Saul, N.; Chakrabarti, S.; Stürzenbaum, S. R.; Menzel, R.; Steinberg, C. E. Hormetins, antioxidants and prooxidants: defining quercetin-, caffeic acid-and rosmarinic acid-mediated life extension in C. elegans. Biogerontology. 2011, 12, 329-347.

556 557 558 559

(57) Kampkötter, A.; Nkwonkam, C. G.; Zurawski, R. F.; Timpel, C.; Chovolou, Y.; Wätjen, W.; Kahl, R. Effects of the flavonoids kaempferol and fisetin on thermotolerance, oxidative stress and FoxO transcription factor DAF-16 in the model organism Caenorhabditis elegans. Arch. Toxicol. 2007, 81, 849-858.

560 561 562

(58) Bischof, L. J.; Huffman, D. L.; Aroian, R. V. Assays for toxicity studies in C. elegans with Bt crystal proteins. In C. elegans; Strange, K., Ed.; Humana Press: Totowa, NJ, 2006; pp 139-154.

563 564 565

(59) Mohan, N.; Chen, C.-S.; Hsieh, H.-H.; Wu, Y.-C.; Chang, H.-C. In vivo imaging and toxicity assessments of fluorescent nanodiamonds in Caenorhabditis elegans. Nano Lett. 2010, 10, 3692-3699.

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Tabular Results

Table 01: Anthocyanin composition and content of Euterpe precatoria (Acai) Identity

[ ] µg.mg-1

Cyanidin-3-Rutinoside

0.5

Cyanidin-3-Glucoside

Traces

Peonidin-3-Rutinoside

Traces

Table 02: DPPH assay. In vitro evaluation of antioxidant effect. Sample

EC50 (µg.mg-1)

Euterpe precatoria (Acai)

3.83 ± 0.04

Vitamin C

2.12 ± 0.04

EGCG

1.03 ± 0.06

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Table 03: Effect of Euterpe precatoria (Acai) on lifespan in C. elegans Mean Lifespan (days)* Strain Genotype

Control

AE 300 µg.ml-1

BA-17

fem-1(hc17)

16.0 ± 3.5

16.0 ± 5.1

TK-22

mev-1(kn1)

15.0 ± 3.5

15.0 ± 4.7

* Mean ± SD

Table 04: Effect of Euterpe precatoria (Acai) on markers of aging and development in C. elegans Body Length*

Brood Size**

Strain

N2 (wt)

Control

AE 300 µg.ml-1

Control

AE 300 µg.ml-1

1261 ± 116

1339 ± 99

183 ± 1

160 ± 7

Results are mean ± SEM. * mean length (µm) and ** mean egg lay 568 569 570 571 572 573 574 575

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Figure 1: Euterpe precatoria extract (AE) protects against oxidative stress in wild-type C. elegans. (a) Effect of AE on stress resistance under a lethal dose of juglone. Survival rate of N2 (wild type) worms was significantly enhanced after AE treatment. (b) Quantification of intracellular ROS levels in N2 worms using DCFDA. Worms treated with AE showed lower levels of ROS compared to the control group. Data are presented as mean ± SEM (n=40, replicated 3 times). ** p< 0.01 and *** p< 0.001, compared to the untreated control by oneway ANOVA followed by Bonferroni (post-hoc).

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Figure 2: Influence of Euterpe precatoria extract (AE) on the expression of stress response genes in C. elegans. (a) AE treatment decreases hsp-16.2 expression in mutant TJ375 worms [hsp-16.2::GFP(gplsI)] treated with pro-oxidant juglone. (b) AE increases sod-3 expression in mutants CF1553 [(pAD76) sod-3p::GFP + rol-6]. Data are presented as mean pixel intensity (mean ± SEM, n=40, replicated 3 times). * p < 0.05, ** p< 0.01 and *** p < 0.001 related to the control, analysed by one-way ANOVA followed by Bonferroni (post-hoc).

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Figure 3: Antioxidant effects of Euterpe precatoria extract (AE) depend on DAF-16/FOXO. (a) AE induces a significant translocation of DAF-16::GFP in mutant TJ356 worms [daf16p::daf-16a/b::GFP + rol-6]. The results are presented as percentage of worms exhibiting a DAF-16 sub-cellular localisation pattern, namely cytosolic, intermediate and nuclear. (b) no significant difference was observed in the survival rate after juglone induced oxidative stress between AE treated and untreated DAF-16 mutant worms (GR1307 [daf-16(mgDf50) I] and CF1038 [daf-16(mu86) I]). Data are presented as mean ± SEM (n=40, replicated 3 times). *** p < 0.001 compared to the untreated control by one-way ANOVA followed by Bonferroni (post-hoc).

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Figure 4: Effect of Euterpe precatoria extract (AE) on aging-related markers. (a) AE attenuates the autofluorescent pigment in N2 (Wild type) worms. Autofluorescent granules were monitored under blue wavelength band. Data are presented as mean ± SEM (n=40, replicated 3 times). (b) AE influences the pharyngeal pumping rate throughout C. elegans aging process. The age-associated decline in muscle function was attenuated by AE treatment in wild-type worms. Data are presented as mean ± SEM (n=30, replicated 3 times). * p < 0.05, ** p< 0.01 and *** p