Purification of Proanthocyanidins from Binchuan Grape Seed and Its Effects on Proliferation of HepG2 Cells

Objective: To study the purification of grape seed proanthocyanidins from Binchuan, Dali, Yunnan and their effects on the proliferation of HepG2 cells. Method: The effects of sample concentration, pH, flow rate, and ethanol volume fraction on the adsorption and resolution of grape seed proanthocyanidins were investigated, and the conditions for the AB-8 type macroporous adsorption resin to purify grape seed proanthocyanidins from Binchuan, Dali, Yunnan were studied. Grape seed proanthocyanidins of different polarities obtained by the ethanol gradient elution during the purification process were applied to HepG2 cells, and the effects of different concentrations of grape seed proanthocyanidins of different polarities on the proliferation of liver cancer HepG2 cells were detected by the CCK8 method. Results: The best process for AB-8 resin to purify grape seed proanthocyanidins was the pH of the sample solution 4.0, the mass concentration was 6.0 mg/mL, the flow rate was 1.0 BV/h, the volume fraction of the eluent was 30%, and the elution volume was 4 BV. This purification increased the content of proanthocyanidins in the grape seed extract from 22.77%±0.32% to 94.73%±0.6429%, with a recovery rate of 80.55%±1.6499%. The polar parts of grape seed proanthocyanidins eluted with 10%, 20%, 30% and 40% ethanol had inhibitory effects on the proliferation of liver cancer HepG2 cells, and the unpurified part (that is, the extract had not been purified by macroporous resin) that inhibitory effect was most significant when the administration concentration was 200 μg/mL (P<0.001). The IC₅₀ of the 10% ethanol group was 25.09 μg/mL, which showed a better inhibitory effect. Conclusion: The grape seed proanthocyanidins in Binchuan, Dali, Yunnan are purified with AB-8 type macroporous resin, and the method is feasible. The grape seed proanthocyanidins have a good inhibitory effect on the proliferation of liver cancer HepG2 cells.