大麦多酚抗氧化及抑菌活性的研究

Antioxidant and Antibacterial Activity of Barley Polyphenols

以大麦为原料提取大麦多酚,利用Fenton反应法、邻苯三酚自氧化法和1,1-二苯基-2-三硝基苯肼(DPPH)比色法分析大麦多酚对羟基自由基(·OH)、超氧阴离子(O2^-·)和DPPH自由基的清除能力。通过抑菌圈直径(DIZ)、最小抑菌浓度(MIC)和最小杀菌浓度(MBC)的测定评估大麦多酚对食源性致病菌的抑菌活性。抗氧化试验表明,0.5 mg/mL的大麦多酚对·OH,O2-·和DPPH·的清除率分别为18.78%,19.31%,82.05%;抑菌试验表明,大麦多酚对金黄色葡萄球菌、单增李斯特菌、鼠伤寒沙门氏菌、大肠杆菌和克罗诺杆菌的抑菌圈直径分别是15.5±0.21,15.3±0.18,16.8±0.17,16.5±0.14,16.6±0.19 mm。大麦多酚对李斯特菌和金黄葡萄球菌的MIC值为2.5 mg/mL,MBC值为5.0 mg/mL;对鼠伤寒沙门氏菌、大肠杆菌和克罗诺杆菌的MIC值都为1.25 mg/mL,MBC值为2.5 mg/mL。可见,大麦多酚具有较好的抗氧化和抑菌活性。

Barley polyphenols were extracted from barley.Fenton reaction method,pyrogallol autooxidation method and 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH)colorimetric method were used to determine the scavenging ability of barley polyphenols to hydroxyl radical(·OH),superoxide anion(O2-·)and DPPH·.The antimicrobial activity of barley polyphenols against foodborne pathogens was evaluated by the determination of inhibitory zone diameter(DIZ),minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC).Antioxidant experiments showed that the scavenging rates of 0.5 mg/mL barley polyphenols on·OH,O2^-·and DPPH·were 18.78%,19.31%and 82.05%,respectively.The antibacterial activity test showed that the DIZs of barley polyphenols against Staphylococcus aureus,Listeria monocytogenes,Salmonella typhimurium,Escherichia coli and Cronobacter were 15.5±0.21,15.3±0.18,16.8±0.17,16.5±0.14,16.6±0.19 mm,respectively.The MIC and MBC values of barley polyphenols against L.monocytogenes and S.aureus were 2.5 mg/mL and 5.0 mg/mL,respectively.MIC values for S.typhimurium,E.coli and Cronobacter were 1.25 mg/mL and MBC values were 2.5 mg/mL.Our findings revealed that barley polyphenols had good antioxidant and antibacterial activities.