Leaf extracts from Teucrium ramosissimum protect against DNA damage in human lymphoblast cell K562 and enhance antioxidant, antigenotoxic and antiproliferative activity

摘要

The in vitro antioxidant, antigenotoxic and antiproliferative activities of Teucrium ramosissimum extracts were investigated. The antioxidant activities of the tested extracts were evaluated through three chemical assays: The Cupric reducing antioxidant capacity, the reducing power and the ferric reducing antioxidant power. TR1 fraction from methanol extract showed the best antioxidant activity evaluated by the CUPRAC, RP and FRAP assays with TEAC values of 4.04, 1.77 and 1.48 μM respectively compared to control. Yet, TR2 fraction exhibited the lowest antioxidant effect with a TEAC values of 1.97, 0.408 and 0.35 μM respectively. All the tested extracts were also found to be effective in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals. Furthermore, the effects of T. ramosissimum extracts on cell proliferation were also examined. The cytotoxic study revealed that methanol extract significantly inhibited the proliferation of K562 cells (IC50= 150 μg/mL). The antigenotoxic properties of these extracts were investigated by assessing the induction and inhibition of the genotoxicity induced by the direct-acting mutagen, hydrogen peroxide (H_2O_2), using an eukaryotic system; the "Comet assay." The results showed that all the extracts inhibited the genotoxicity induced by H_2O_2, and particularly TR2 fraction (96.99%) and methanol extract (96.64%). The present study has demonstrated that T. ramosissimum extract possess potent antioxidant, antiproliferative and antigenotoxic activities, which could be derived from compounds such as flavonoids and polyphenols.