The three water-soluble polysaccharides （PI, PII and Pill）, the ethyl acetate extraction （EA） and its five fractions of petroleum ether （PeF）, ethyl acetate （EaF）, butanol （BuF）, methanol （MeF） and water ...The three water-soluble polysaccharides （PI, PII and Pill）, the ethyl acetate extraction （EA） and its five fractions of petroleum ether （PeF）, ethyl acetate （EaF）, butanol （BuF）, methanol （MeF） and water （WtF） from marine agrobacterium 1202 were prepared and then subjected to antioxidant activity evaluation. The antioxidant activity was tested using the 1, 1-Diphenyl-2-picryl-hydrazyl （DPPH） free radical-scavenging assay, the hydrogen peroxide-induced luminot chemiluminescence （CL） assay and hydroxyl free radical-initiated chemiluminescence （CL） assay. All the fractions exerted significant inhibitory effects on hydrogen peroxide and hydroxyl free radical. The extracts of EA, EaF and BuF could also showed inhibition on DPPH. Among of them, the extracts of EaF showed full of antioxidant activity on the three tested system. The result suggested that the marine agrobacterium 1202 is a potential source of natural antioxidantagent.展开更多
Five hydroxystilbene derivatives were synthesized and their structures were determined using high-resolution mass spectrometry, ^1H NMB, and IR. In this study, the antioxidant activities of eight hydroxystilbenes （fi...Five hydroxystilbene derivatives were synthesized and their structures were determined using high-resolution mass spectrometry, ^1H NMB, and IR. In this study, the antioxidant activities of eight hydroxystilbenes （five synthesized hydroxystilbene derivatives and three other compounds） were evaluated with the free radiced scavenging model 1,1-diphenyl-2-picrylhydraxyl. It was observed that there exists a very significant linear rehtionship between the reciprocal of the EC50 value of each of the compounds and the maximum wavelength of the ultraviolet absorption peaks, It is believed that this result will be helpful for the further synthesis of such antioxidants.展开更多
测定不同质量浓度类胡萝卜素在不同温度条件下清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基的能力;考察经人工胃液、肠液及胃液-肠液3种方法模拟消化后类胡萝卜素清除DPPH自由基能力的变化情况。结果表明:...测定不同质量浓度类胡萝卜素在不同温度条件下清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基的能力;考察经人工胃液、肠液及胃液-肠液3种方法模拟消化后类胡萝卜素清除DPPH自由基能力的变化情况。结果表明:反应温度(T)对类胡萝卜素清除DPPH自由基的速率(k)影响显著(P<0.05),T升高,k增大,即k45℃>k37℃>k30℃,而对清除率(α)无显著影响;类胡萝卜素初始质量浓度(ρ)对α影响显著,ρ升高,α增大,而对k无显著影响;类胡萝卜素对DPPH自由基的清除作用符合一级反应动力学模型;T对半数效应浓度(EC50)、k和半衰期(t1/2)影响显著,T升高,EC50减小(EC50(45℃)<EC50(37℃)<EC50(30℃))、k增大(k45℃>k37℃>k30℃)、t1/2减小(t1/2(45℃)<t1/2(37℃)<t1/2(30℃));表观活化能(Ea)和方程常数(K0)不受ρ的影响,Ea=17.039 k J/mol、K0=7.38×106;体外模拟消化后的类胡萝卜素对DPPH自由基的清除率减小,且底物浓度越大,清除率下降百分比越大,降幅越小;与油脂混合后的类胡萝卜素经体外模拟消化后对DPPH自由基的清除率低于不加油脂组,即脂溶性的类胡萝卜素与油脂混合后更易被人体消化吸收,但因不同植物油的脂肪酸组成不同,对其消化吸收的影响存在差异。展开更多
文摘The three water-soluble polysaccharides （PI, PII and Pill）, the ethyl acetate extraction （EA） and its five fractions of petroleum ether （PeF）, ethyl acetate （EaF）, butanol （BuF）, methanol （MeF） and water （WtF） from marine agrobacterium 1202 were prepared and then subjected to antioxidant activity evaluation. The antioxidant activity was tested using the 1, 1-Diphenyl-2-picryl-hydrazyl （DPPH） free radical-scavenging assay, the hydrogen peroxide-induced luminot chemiluminescence （CL） assay and hydroxyl free radical-initiated chemiluminescence （CL） assay. All the fractions exerted significant inhibitory effects on hydrogen peroxide and hydroxyl free radical. The extracts of EA, EaF and BuF could also showed inhibition on DPPH. Among of them, the extracts of EaF showed full of antioxidant activity on the three tested system. The result suggested that the marine agrobacterium 1202 is a potential source of natural antioxidantagent.
基金Supported by the National Natural Science Foundation of China(No. 20372014).
文摘Five hydroxystilbene derivatives were synthesized and their structures were determined using high-resolution mass spectrometry, ^1H NMB, and IR. In this study, the antioxidant activities of eight hydroxystilbenes （five synthesized hydroxystilbene derivatives and three other compounds） were evaluated with the free radiced scavenging model 1,1-diphenyl-2-picrylhydraxyl. It was observed that there exists a very significant linear rehtionship between the reciprocal of the EC50 value of each of the compounds and the maximum wavelength of the ultraviolet absorption peaks, It is believed that this result will be helpful for the further synthesis of such antioxidants.
文摘测定不同质量浓度类胡萝卜素在不同温度条件下清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基的能力;考察经人工胃液、肠液及胃液-肠液3种方法模拟消化后类胡萝卜素清除DPPH自由基能力的变化情况。结果表明:反应温度(T)对类胡萝卜素清除DPPH自由基的速率(k)影响显著(P<0.05),T升高,k增大,即k45℃>k37℃>k30℃,而对清除率(α)无显著影响;类胡萝卜素初始质量浓度(ρ)对α影响显著,ρ升高,α增大,而对k无显著影响;类胡萝卜素对DPPH自由基的清除作用符合一级反应动力学模型;T对半数效应浓度(EC50)、k和半衰期(t1/2)影响显著,T升高,EC50减小(EC50(45℃)<EC50(37℃)<EC50(30℃))、k增大(k45℃>k37℃>k30℃)、t1/2减小(t1/2(45℃)<t1/2(37℃)<t1/2(30℃));表观活化能(Ea)和方程常数(K0)不受ρ的影响,Ea=17.039 k J/mol、K0=7.38×106;体外模拟消化后的类胡萝卜素对DPPH自由基的清除率减小,且底物浓度越大,清除率下降百分比越大,降幅越小;与油脂混合后的类胡萝卜素经体外模拟消化后对DPPH自由基的清除率低于不加油脂组,即脂溶性的类胡萝卜素与油脂混合后更易被人体消化吸收,但因不同植物油的脂肪酸组成不同,对其消化吸收的影响存在差异。
