Abstract: Using AB-8 macroporous resin as carrier and gradiently eluted by 10%,30%,50% ethanol,the purified samples were screened with the content of total flavonoids and flavonoid aglycones.The MTT assay and RTCA were used to examine inhibitory effect of flavonoids from Sea buckthorn on PC-3 cells.Flow-cytometry was used to analyze the cell apoptosis and cell cycle of the PC-3 cells.The expressions level of Bax and Bcl-2 were detected by Western blot.The results showed that in the gradient elution of 50% ethanol solution (S₅₀),the content of total flavonoids was 25.42%,hydrolyzing it to get SH₅₀ sample,which quercetin and isorhamnetin content reached 5.03% and 18.64% respectively;SH₅₀ (25 μg/mL) can inhibit the activity of PC-3 cells and showed the feature of time /dose dependent;25 μg/mLSH₅₀ can also induce the apoptosis of PC-3 cells significantly (P<0.01) and block the cell cycle at G2/M stage after treated 48h.Moreover,SH₅₀ can increase the activities of Bax but decrease the expression level of Bcl-2.These results demonstrated that SH₅₀ can inhibit the proliferation and induce cell apoptosis of PC-3 cells in vitro,the mechanism might be related with the blocking of the cell cycle and regulating the expression levels of Bax and Bcl-2.  

Key words: sea buckthorn flavonoids ;human prostate cancer, PC-3 cells, inhibit the proliferation