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Chapter 5
Effect of Lactic Acid Fermentation on Quercetin Composition and Antioxidative Properties of Toona sinensis Leaves 1
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Tzou-Chi Huang , Hseng-Kuang Hsu , Hui-Yin Fu , and Chi-Tang Ho 4
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Department of Food Science, National Pingtung University of Science and Technology, 912, Pingtung, Taiwan Department of Physiology, Kaohsiung Medical University, Kaohsiung, Taiwan Department of Food Sanitation, Tajen Institute of Technology, 912, Pingtung, Taiwan Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901-8520 2
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Flavonoids of fresh and lactic acid bacteria fermented Toona sinensis (Cedrela sinensis A. Juss) leaves were extracted and analyzed using HPLC. Rutin was characterized as the major quercetin derivative in fresh Toona sinensis leaf, whereas aglycone concentration increased after lactic acid bacteria fermentation. DPPH radical scavenging activity was used to evaluate the antioxidant activity. The β-glucosidases in both Toona sinensis and lactic acid bacteria were detected during fermentation resulting in a release of free hydroxyl groups from the quercetin molecule. The increased hydroxyl groups could be attributed to the increase of free radical scavenging activities of the fermented Toona sinensis leaves. The increased absorption of quercetin in rat could be attributed to the released quercetin-3-glucoside from rutin in fermented Toona sinensis leaves.
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© 2005 American Chemical Society In Phenolic Compounds in Foods and Natural Health Products; Shahidi, F., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2005.
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Introduction In traditional Chinese medicine, leaf extract of Toona sinensis has many biological functions, especially its therapeutic effect on abdominal tumors. The leaves and stems of Toona sinensis Roemor have long been used for the treatment of enteritis, dysentery and itch in Oriental medicine (7). Evidence has shown that the components of Toona sinensis exert potent anti-inflammatory and analgestic actions, and inhibit boil growth in vivo (2). Recently crude extract from leaves of Toona sinensis was found to effectively block the cell cycle progression of human lung cancer cells by inhibiting the expression of cyclin D l and Ε in A549 cells. Additionally, incubation of the extract led to activation of caspase-3-like proteases and apoptotic cell death. However, the extract did not show any significant cytotoxic effect on cultured human foreskin fibroblasts or MRC-5 human lung fibroblasts (5). Few studies have been carried out on the chemical composition of Toona sinensis. Limonoids, sterols, sesquiterpenes, triterpenoids and flavonoids are reported to be the major components in Toona (Meliaceae). While investigating Cedrela sinensis, cedrellin, 2,6,10,15-phytatetraene-14-ol, 7-a-obacunyl acetate, 6-acetoxyobacunol acetate, 7-a-acetoxydihydronomilin, 2,6,10-phytatriene1,14,15-triol and phytol were identified (4). A number of compounds, including retinoid, vitamins Β and C, o-coumaric acid, kaempferol, methyl gallate, quercetin, afzelin, quercitrin, isoquercitrin and rutin have been isolated from the leaves of Cedrela sinensis (5). Park et al (6) reported that methyl gallate, quercitrin, bis-(/?-hydroxyphenyl) ether, adenosine, isoquercitrin, rutin, (+)catechin and (-)-epicatechin were isolated and characterized from rachis of Cedrela sinensis A. Juss. Fresh Toona sinensis leaf samples, whole or chopped, were ensilaged in an airtight mason jar. Spontaneous fermentation started to occur after two days of storage at ambient temperature (25±3 °C). A sharp decline in Toona sinensis silage pH from 6.4 to 4.5, followed by the continuing fermentation to a final pH of 4.2 for the whole leaf samples was observed, as shown in Figure 1. The change of pH value in the fermented chopped Toona sinensis leaf followed a similar tendency, with faster acid production than that of the whole leaf. This result indicates that sugars in the chopped sample were released and utilized more efficiently than in the whole leaf and lead to faster decline of pH value. Organic acids identified by HPLC in solid-fermented Toona sinensis include lactic and acetic acids (Table I). The concentration of lactic acid increased
In Phenolic Compounds in Foods and Natural Health Products; Shahidi, F., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2005.
Downloaded by UNIV OF CALIFORNIA SAN FRANCISCO on December 14, 2014 | http://pubs.acs.org Publication Date: July 21, 2005 | doi: 10.1021/bk-2005-0909.ch005
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0 2 4 6 8 1012141618202224262830 Incubation time (day) Figure 1. Changes ofpH in naturally fermented Toona sinensis leafsilage.
quickly with increasing fermentation time until a value of 63±5 g/Kg dry matter was reached after 4 weeks. In addition to lactic acid, a significant amount of acetic acid (28±5 g/Kg dry matter) was produced as well, after 30 days incubation. During the first two weeks, significantly higher amounts of lactic acid (41 ±3 g/Kg dry matter) and acetic acid (21 ±2 g/Kg dry matter) were observed in the chopped Toona sinensis leaves. There was no significant (p
