副干酪乳杆菌及其胞外多糖的抗氧化性研究

以具有抗氧化性的嗜酸乳杆菌ATCC4356为对照,研究了1株副干酪乳杆菌H9的抗氧化性。分析了2株菌不同浓度下菌悬液和无细胞提取液的DPPH自由基清除能力、金属离子螯合能力和抑制脂质过氧化能力。并对H9菌株菌悬液煮沸灭活前后的抗氧化能力进行了比较。同时,对H9菌株自产的胞外多糖的抗氧化性进行了研究,测定了其在不同浓度下DPPH自由基清除能力、超氧自由基清除能力、羟自由基清除能力。结果表明:H9菌株的菌悬液和无细胞提取液抗氧化能力均随着浓度的升高呈上升趋势,浓度达到109cfu/mL时抗氧化能力最强,此时DPPH的清除能力分别达到(55.0±1.7)%和(47.5±1.8)%,螯合金属离子的能力分别为(15.2±1.2)%和(15.1±1.3)%,抑制脂质过氧化的能力分别为(76.2±1.1)%和(70.0±0.4)%。煮沸后菌悬液抗氧化能力趋势与未煮沸前一致,但同等浓度下煮沸处理会降低其抗氧化能力。H9菌株自产胞外多糖也具有较强的抗氧化能力,并随着多糖浓度的升高抗氧化能力增强。结果表明H9菌株的抗氧化性可能与活细胞和菌体代谢产物密切相关。

Antioxidant activity of Lactobacillus paracase and its exopolysaccharides

In order to evaluate the antioxidant activity of Lactobacillus paracase H9,Lactobacillus paracasei ATCC4356 with antioxidative activity was applied as standard strain.Intact cells and intracellular cell-free extracts in different concentrations of H9 and ATCC4356 were investigated.DPPH free radical scavenging,chelating metal and inhibiting lipid peroxidation ability were determined of both strains.The antioxidant activity of intact cells after inactivation were compared.Exopolysaccharides of H9 was extract,and the DPPH,hydroxyl free radical and superoxide anion elimination ability of exopolysaccharides in different concentrations were determined.The results demonstrated that the antioxidant activity of Lactobacillus paracase H9 of intact cells and intracellular cell-free extracts enhanced as the concentrations increasing.The intact cells and intracellular cell-free extracts of H9 can chelate metal by(15.2±1.2)% and(15.1±1.3)%,scavenge DPPH free radical by(55.0±1.7)% and(47.5±1.8)%,inhibite lipid peroxidation by 76.2±1.1% and(70.0±0.4)%.The tendency of heat-inactivated intact cells consistent with antioxidative activity before inactivation and inactivation decrease the antioxidative activity.The strong antioxidant activity of exopolysaccharides demonstrated that antioxidant activity of H9 should be related to active cells or active components in cells.