Effects of Geven root extract on proliferation of HeLa cells and bcl-2 gene expressions
Geven (Astragalus L.) root extract is used for asthma, diarrhea, and cancer therapy in Chinese Medicine. Liquid Astragalus root extracts are traditionally used in Anatolia for leukemia and wound healing. 439 species of this plant, which has 3000 species in the world, grow in Turkey and 204 of these are endemic. In this study, molecular mechanism of apoptotic and cytotoxic effects of root ethyl acetate extract of Astragalus chrysochlorus on HeLa cells was investigated. For this purpose, 1, 0.5, 0.15 and 0.1 mg/ml concentrations of Astragalus root extract were applied to HeLa cell cultures for 24, 48 and 72 h. Cell kinetic parameters as proliferation rate (MTT assay), Mitotic Index and apoptotic index were used for experimental cytotoxicity assay of root extract. Furthermore, effects of root extract on gene expression rates which take place in apoptosis mechanism as Bcl-2, Bax, Bak, Bcl-x, Bik, Mcl-1, Bfl-1 were determined by reverse transcription-polymerase chain reaction (RT-PCR) technique. As a result of investigated parameters, root extract of Astragalus chrysochlorus is found to have cytotoxic effect on HeLa cell cultures. This cytotoxic effect which appeared in our experiments achieved statistically significant decrease on proliferation rate of HeLa cells depending on application time and concentration. Also mitotic index and apoptotic index presented statistically significant increase on particular concentrations and hours (p < 0.05). Likewise, it is determined on molecular basis that root extract causes significant changes on especially antiapoptotic genes.
Key words: Astragalus chrysochlorus, HeLa cells, Cytotoxicity, Apoptosis, bcl-2 gene family.