Purification of Different Phenolic Compounds from Sorghum Bran on AB-8 Macroporous Resin and Protective Effects against Oxidative-stress-induced Erythrocyte Hemolysis

CHEN Hua-min; LAI Fu-rao; SUN Chong-zhen; ZHANG Meng-meng; WU Hui; TANG Yu-qian; LI Xiao-feng

doi:10.13982/j.mfst.1673-9078.2017.9.009

Abstract：Different types of phenols extracted from sorghum bran were purified on the AB-8 macroporous resin and then analyzed by high performance liquid chromatography (HPLC).The inhibitory effects of the phenols on human-erythrocyte hemolysis caused by 2,20-azobis-(2-amidinopropane) dihydrochloride (AAPH) were studied.The results showed that after purification on the AB-8 macroporous resin,phenol concentrations were in the following order:free phenols ＞ insoluble bound esterified phenols ＞ insoluble bound glycosidic phenols ＞ soluble glycosidic phenols ＞ soluble esterified phenols.According to the results of HPLC,the concentrations of 18 phenolic compounds were in the following order:insoluble bound esterified phenols ＞ free phenols ＞ insoluble bound glycosidic phenols ＞ soluble esterified phenols ＞ soluble glycosidic phenols.After the treatment with 200 μg/mL insoluble bound esterified,free,insoluble bound glycosidic,or soluble esterified phenols,the rate of AAPH-induced hemolysis of erythrocytes decreased to ～10％,which was close to that of the negative control group;the AAPH hemolysis rate of erythrocytes in the soluble glycosidic phenolic (200 μg/mL) treatrnent group was still 28.84％.Pretreatments with five different types of phenols effectively reduced the concentration of malondialdehyde (MDA),increased the glutathione/glutathione disulfide (GSH/GSSG) ratio in the AAPH-treated erythrocytes,and restored the erythrocytes to the normal state.The erythrocytes with relatively low superoxide dismutase (SOD),catalase (CAT),and glutathione peroxidase (GSH-Px) activities were also protected.In conclusion,the different types of phenols from sorghum bran after purification on the AB-8 macroporous resin may protect human erythrocytes from the damage caused by AAPH-generated free radicals,and their intracellular antioxidant activity is related to their total phenolic content and composition of a mixture of phenolic compounds.