Study On Antioxidant Activity Of Polysaccharides From Brassica Rapa L. And Its Effect On Proliferation And Apoptosis Of SW620 Cells

ObjectiveThese paper studyed the antioxidative activity of polysaccharides from Brassica rapa L.(BLP)in vitro and its effect on the proliferation and apoptosis of SW620 cells.so as to explore its related mechanisms and.to provide a theoretical basis for the research on the biological activity of BLP.Methods(1)After degreasing the root of turnip,the extraction solution was prepared by ultrasonic assisted extraction with water as solvent.The BLP was obtained by freeze-drying after Sevage reagent deproteinization and depigmentation of activated carbon.The phenol sulfuric acid method was used to determine the BLP content in the extract and the methodological investigation was carried out.(2)Using ascorbic acid as a positive control,the scavenging effects of DPPH free radicals,hydroxyl free radicals,and ABTS free radicals of BLP were measured to evaluate the antioxidative capacity of BLP in vitro.(3)SW620 cells were treated with low(2 mg/mL),medium(4 mg/mL),and high(8 mg/mL)concentrations of BLP for 12 h,24 h,and 48 h respectively.In addition,a negative control group and a blank group were set up,and the effect of BLP on cell proliferation was detected by CCK-8 method.(4)BLP intervened in SW620 cells for 24 h,and a negative control group was set up.The effects of BLP on apoptosis of SW620 cells were detected by flow cytometry after Annexin V-FITV/PI double staining;The effect of BLP on cell cycle distribution of SW620 was detected by flow cytometry after PI single staining.The expression levels of Bax,Bcl-2,cleaved caspase-3 and cleaved PARP in SW620 cells were detected by Western Bolt assay.(5)The data were analyzed with SPSS 25.0 statistical software.Results(1)The BLP content in water extract was 18.25%.The results of methodology test showed that the precision,stability,repeatability and recovery were good.(2)Compared with the ascorbic acid group,the scavenging ability of BLP on DPPH· and ABTS+·was weaker,and the scavenging ability of BLP on·OH was stronger.(3)The results of CCK-8 assay showed that the proliferation activity of SW620 cells decreasing after 12 h,24 h and 48 h intervention on BLP compared with the control group(P<0.05).(4)Annexin V-FITV/PI double-staining assay showed that after 24 h of BLP intervention in SW620 cells,the apoptosis rates of the low,medium and high dose groups increased by 4.97%,6.91%and 13.08%respectively,compared with 2.20%in the control group.(5)Flow cytometry showed that the cell proportion of G0/G1 phase decreased with the increase of BLP concentration compared with the control group(P<0.05),and there was no statistically significant difference between the medium and high dose groups(P>0.05).The cell proportion of S phase increased compared with the control group(P<0.05),and the difference of between BLP groups was statistically significant(P<0.05).The cell number decreased in G2/M phase compared with the control group(P<0.05),and the difference between the low and medium dose groups was insignificant(P>0.05).(6)The results showed that the expression of Bax,cleaved-caspase 3 and cleaved-PARP proteins in SW620 cells increased with the increased concentration of BLP,and the expression of Bcl-2 protein decreased significantly.Conclusions(1)The content of BLP in Xinxiang,Henan is 18.25%.(2)BLP is a strong natural antioxidant.(3)BLP can inhibit the proliferation activity of SW620 cells and promote their apoptosis.The mechanism of action may be related to the fact that BLP can block SW620 cells in S phase,promote the expression of Bax,cleaved caspase 3 and cleaved PARP,and inhibit the expression of Bcl-2.