Protective Effects of Aqueous and Ethanolic Extracts of Portulaca oleracea L. Aerial Parts on H 2O 2- Induced DNA Damage in Lymphocytes by Comet Assay

摘要

The comet assay is a standard method for measuring DNA damage. In this study, the protective effects of ethanolic and aqueous extracts ofPortulaca oleraceaL. (P. oleracea) on human lymphocyte DNA lesions were evaluated with the comet assay. Lymphocytes were isolated from blood samples taken from healthy volunteers. Human lymphocytes were incubated in H2O2(50,100, and 200μM), aqueous extract (0.05, 0.1, 0.5, 1, and 2.5mg/ml), and ethanolic extracts (0.05, 0.1, 0.5, 1, and 2.5mg/ml) ofP. oleraceaeaerial parts alone with a combination of H2O2(100μM) with either 1 or 2.5mg/ml of both extracts at 4°C for 30 minutes. The extent of DNA migration was measured using the alkaline single cell gel electrophoresis approach assay, and DNA damage was expressed as percentage tail DNA. We found that the aqueous extract ofP. oleraceasignificantly inhibited DNA damage, while there was no effect of the ethanolic extract. These data suggest that the aqueous extract ofP. oleraceacan prevent oxidative DNA damage to human lymphocytes, which is likely due to antioxidant constituents in the extract.