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Antimutagenic properties of grape seeds

Mahidol University and The Thailand Institute of Scientific and Technological Research have been working together in collaboration to investigate the biological properties of oligomeric proanthocyanidins (OPCs) which are found in red grape seeds. OPCs are a class of flavonoid complexes and are found in most plants, consequently, they are part of the natural human diet. Many publications have reported that OPCs possess excellent antioxidant effects. Previously, OPCs have to been linked to a reduced risk of chronic disease and cancer. Here, the antimutagentic properties of OPCs were investigated using the micronucleus (MN) test and the comet assay.

The investigations were conducted to examine the cytotoxicity, the antimutagenic and antioxidant properties of OPCs in a human cell line (lymphoblastoid TK6 cells) by using the MN and the comet assay. In the MN assay, OPCs-treatment of TK6 cells at concentrations between 10 - 200 μg/ml (at both 4 and 24 hours) did not cause micronucleus induction when compared with the negative control group, but there was a significant reduction the micronucleus frequencies against the known mutagen (mitomycin C).

In the comet assay, OPCs-treated TK6 cells at concentrations of 100, 250, 500, and 1,000 μg/ml could inhibit DNA damage induced by H2O2. The comet assay was performed following the method described by Tice et al.. Fifty cells per slide per treatment were randomly analysed using a fluorescence microscope connected to a computer equipped with the image analysis system provided by Perceptive Instruments. Two parameters, tail length and tail moment, were considered as indicator of DNA damage. Then, a one-way ANOVA-test was performed to determine the statistical significance of the results.

The results obtained during this investigation suggest that OPCs possess antimutagenic and antioxidative DNA damage effects in TK6 cells under the conditions of these assays. The study revealed that the human TK6 lymphoblastoid cells could be a useful model for the testing of unknown genotoxic compounds using the MN test and the comet assay. The OPCs studied here might be a new candidate or an alternative compound used for antimutagenic and antioxidative DNA damage activities. Although the exact mechanism by which the protective effect of OPCs is not completely understood, it is postulated that it might be due to their antioxidant property. The authors discuss that future studies can be conducted to find out the mechanism(s) of action of OPCs by both in vivo and in vitro experiments, and this information may be beneficial for the potential use of OPCs as a health promoter and nutraceutical.

This case study is based on:
Antimutagenicity and Antioxidative DNA Damage Properties of Oligomeric Proanthocyanidins from Thai Grape Seeds in TK6 Cells
Asian Pac J Cancer Prev. 2011;12(5):1317-21.
Praphasawat R, Klungsupya P, Muangman T, Laovitthayanggoon S, Arunpairojana V, Himakoun L.