Antiproliferative effect of flavonoids from the halophyte Vitex rotundifolia on human cancer cells.

Three flavonoids, luteolin (1), vitexicarpin (2) and artemetin (3), from the salt marsh plant Vitex rotundifolia, were tested for their anti-proliferative activities in AGS, MCF-7 and HT-29 human cancer cell lines and compared with the control using MTT assay. Among them, 2 was most effective with an IC50 of 6.9 and 22.8 microM against AGS and HT-29 cells, respectively. Inaddition, mRNA expression levels of major apoptosis-related genes such as p21, p53, Bcl-2 andBax in AGS cells were evaluated by reverse-transcription polymerase chain reaction (RT-PCR). Compound 2 not only enhanced most remarkably the expression level of tumor suppressor genes p53 and p21, and pro-apoptotic gene Bax at a concentration of 25 microM, but also suppressed the expression level of antiapoptotic gene Bcl-2 to 20% at the same concentration, thus shifting the Bax/Bcl-2 ratio in favor of apoptosis.