Inhibition effects and induction of apoptosis of flavonoids on the prostate cancer cell line PC-3 in vitro

Myricetin and myricitrin are naturally occurring flavonoids have been suggested to play a role in inhibition of proliferation and transformation of carcinogenic cell. However, the underlying molecular mechanisms of their activity have not yet to be revealed. The aim of the present study was to clarify the molecular mechanisms of apoptosis cell on the prostate cancer induced by myricetin, myricitrin, quercetin and quercitrin. The MTT assay confirmed that myricetin had the strongest inhibitory effect on human prostate cancer cell line PC-3, myricitrin was second, and quercitrin was the weakest. A noticeable synergistic effect was observed with the inhibition of cell proliferation when myricetin was used in combination with myricitrin. In the concentration range of 37.5–300 μmol/L, the inhibitory effects of these flavonoids were enhanced with increasing dose and treatment time. The acridine orange analysis and annexin V–FITC/PI double-staining results confirmed that myricetin and myricitrin were effective in inducing PC-3 cell apoptosis. The results showed that myricetin was more effective than myricitrin in inducing cell apoptosis. The apoptosis rate increased with increasing flavonoid concentration in a dose dependent manner. A synergistic effect was observed on the apoptosis rate when myricetin was used in combination with myricitrin.