14E-21 |
Evaluation of antioxidant activity of Vigna sinensis seed extract and its protective effect on hydrogen peroxide-induced DNA damage |
Y. S. WONG1, Y. T. Chiang, and C. C. Chan. (1) Biology Department, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China Free radicals and reactive oxygen species (ROS) are produced in living cells during normal metabolic process. The mechanism of the free radical reaction is associated with the pathology of some human chronic diseases such as cancer and atherosclerosis. Antioxidants can protect the body from free radicals and ROS attack. Our dietary antioxidants include vitamin C, vitamin E, carotenoids and polyphenolic compounds such as flavonoids. We investigate flavonoid antioxidants in different edible legume seeds. Our objectives were to evaluate the antioxidant activity of Vigna sinensis seed extract and its protective effect on hydrogen peroxide-induced DNA damage. DPPH radical scavenging method and beta-carotene bleaching method were used to determine the antioxidant activities of various seed extracts. Flavonoids in Vigna sinensis seed were extracted by acidic methanol. The seed extract was further subject to HPLC analysis. Single cell gel electrophoresis (comet assay) was employed to assess the protective effects of flavonoid antioxidants on hydrogen peroxide-induced DNA damage using the mouse blood cells as a model system. In a survey on twenty-four selected edible legume seeds, hak-mei-tau, a local black seed cultivar of Vigna sinensis, exhibited high antioxidant activity and high free radical scavenging ability. This seed extract was shown to have protective effect on hydrogen peroxide-induced DNA damage in mouse blood cells. By comparison of the retention time with flavonoid standards, fifteen flavonoids were identified in the seed extract with a total content over 2 mg/g dry wt. Most of these individual identified flavonoids exhibited significant protective effects on hydrogen peroxide-induced DNA damage. Our results suggest that edible legume seeds are a good source of dietary flavonoids. One of the health beneficial properties of flavonoid antioxidants may associate with their ability to protect DNA from damage caused by free radicals and ROS generated during cellular metabolism.
Session 14E, Nutraceuticals & Functional Foods: General I
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