BCP was extracted by hot water extraction method. The antioxidant activities of BCP including the hydroxyl radical scavenging rate，the total antioxidant capacity and the anti-superoxide anion activities were detected，and compared to the antioxidant activities of vitamin E.The HK-2 cells were treated with different concentrations of BCP and D-gal，respectively，and the proliferation rates of HK-2 cells were detected；the optimum concentrations of BCP and D-gal were confinmed.D-gal was used to establish the oxidative damage model of proximal convolve tubule of human kidney.The HK-2 cells were divided into control group，D-gal group，and 25，50，100，200，400 mg·L^－1 BCP+D-gal groups；MTT method was used to detect the proliferation rates.The HK-2 cells were divided into control group，D-gal group，BCP+D-gal group and vitamin E+D-gal group；senescence-associated β-galactosidase（SA-β-Gal） staining was used observe the SA-β-gal staining of the HK-2 cells in various groups and the percentages of senescent the HK-2 groups cells were calculated.

The antioxidant activity detection results showed that compared with vitamin E group with the same concentration， the scavenging rates of hydroxyl free radical in different concentrations of BCP groups were increased（P<0.05）， and the total antioxidant capacitie were increased（P<0.05）； the anti-superoxide anion activities in 5，10，and 15 g·L^－1 BCP groups were significantly increased（P<0.05）， and the antioxidant levels in vitro in different concentrations of BCP groups were higher than those in vitamin E groups with the same concentration. Compared with control group，the proliferation rates of HK-2 cels in 25－400 mg·L^－１ BCP groups were increased in a concentration-dependent manner after treated for 24 h， and the proliferation rate of HK-2 cells in 200 mg·L^－1 BCP group was the highest （P<0.05）. Compared with control group， the proliferation rates of HK-2 cells in different concentrations of D-gal groups were decreased in a time-dose dependent manner； when the treatment conditions were 20 g·L^－1 and 48 h， the proliferation rate of cells was decreased to 64.77% of that in control group （P<0.05）.Compared with control group，the proliferation rate of HK-2 cells in D-gal group was significantly decreased（P<0.05）； compared with D-gal group， the proliferation rates of HK-2 cell in 100－400 mg·L^－1 BCP group increased in a dose-dependent manner （P<0.05 or P<0.01）. Compared with control group， the number of SA-β-gal positive staining cells in D-gal group was significantly increased（P<0.05）， and the percentage of senescent cells was increased （P<0.05）； compared with D-gal group， the number of SA-β-gal positive staining cells in BCP+D-gal group and vitamin E+D-gal group was significantly reduced（P<0.05）， and the percentages of senescent cells were decreased （P<0.05）.

BCP has a strong antioxidant activity in vitro and protects the oxidative damage of HK-2 cells induced by D-gal by inhibiting cell senescence.