Corn peptides(CP) were prepared from zein via proteolysis by means of a type of alkaline protease, Alcalase, at 50 ℃ and pH 8.0. The anti oxidative activity of the hydrolysate was examined. It was found that the...Corn peptides(CP) were prepared from zein via proteolysis by means of a type of alkaline protease, Alcalase, at 50 ℃ and pH 8.0. The anti oxidative activity of the hydrolysate was examined. It was found that the anti oxidative activity reached the maximum at the fourth hour of the hydrolysis and then decreased. The effect of the enzyme dosage on the solubility of corn protein, the dependence of hydrolysis time on the degree of the hydrolysis(DH) and molecular weight distribution were examined respectively. 30% DH was controlled on the basis of anti oxidative activity. The hydrolysate was fractionated on a Sephadex G 15 column. The anti oxidative activities were examined for all the fractions. The main fraction for anti oxidative activity was collected and characterized by the methods of amino acid analysis, the measurement of average chain length and etc .. The main M W distribution of the main fraction was 300-600 Daltons. The anti oxidative properties of the small peptides in vitro were studied. It was found that they could inhibit the auto oxidation of pyrogallol and the oxidation of hemoglobin. The hemolysis degree of erythrocyte caused by hydroxyl free radicals was decreased greatly, indicating a protective effect of the anti oxidative peptides on the cell membrane damage of erythrocyte.展开更多
6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H...6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.展开更多
Background Taxifolin（Tax） is an essential natural antioxidant. Multiple studies have shown that Tax can protect cardiomyocytes from ischemia-reperfusion injury. However, the underlying mechanism is still unclear.Met...Background Taxifolin（Tax） is an essential natural antioxidant. Multiple studies have shown that Tax can protect cardiomyocytes from ischemia-reperfusion injury. However, the underlying mechanism is still unclear.Methods H9C2 cells were randomly divided into control, H_2O_2 group, Tax pretreatment group（Tax ＋ H_2O_2）;Tax effect group. Cell activity was detected by CCK-8 and the intracellular structure was observed by transmission electron microscopy. Autophagy was determine by Western blotting analysis of Beclin-1, Bcl-2 and PKC.Results Tax pretreatment significantly increased anti-apoptotic protein Bcl-2 and autophagy protein Beclin-1.Expression of PKC was inhibited by Tax. Conclusions Tax pretreatment could protect H9 C2 cells against H_2O_2-induced damage through the Bcl-2 and autophagy pathways.展开更多
The anti-oxidation performance of 3,7-di-iso-octyl-phenothiazine was measured in group Ⅰ,Ⅱ and Ⅳ base oils by rotating pressure vessel oxidation testing(RPVOT),pressure differential scanning calorimetry(PDSC)and ag...The anti-oxidation performance of 3,7-di-iso-octyl-phenothiazine was measured in group Ⅰ,Ⅱ and Ⅳ base oils by rotating pressure vessel oxidation testing(RPVOT),pressure differential scanning calorimetry(PDSC)and aging test,and its synergistic effect with 4,4′-di-iso-octyl-diphenylamine was examined.The results indicated that 3,7-di-iso-octyl-phenothiazine showed longer oxidation induction period and lower acid number increase than 4,4′-di-iso-octyl-diphenylamine,and their notable synergistic effect was observed.It was found that the anti-oxidation characteristics of the above-mentioned antioxidants were strongly affected by the composition of the corresponding base oil.展开更多
基金Supported by the Science and Technology Comm ission of Jinlin Province(No. 94 35 4 6 - 3)
文摘Corn peptides(CP) were prepared from zein via proteolysis by means of a type of alkaline protease, Alcalase, at 50 ℃ and pH 8.0. The anti oxidative activity of the hydrolysate was examined. It was found that the anti oxidative activity reached the maximum at the fourth hour of the hydrolysis and then decreased. The effect of the enzyme dosage on the solubility of corn protein, the dependence of hydrolysis time on the degree of the hydrolysis(DH) and molecular weight distribution were examined respectively. 30% DH was controlled on the basis of anti oxidative activity. The hydrolysate was fractionated on a Sephadex G 15 column. The anti oxidative activities were examined for all the fractions. The main fraction for anti oxidative activity was collected and characterized by the methods of amino acid analysis, the measurement of average chain length and etc .. The main M W distribution of the main fraction was 300-600 Daltons. The anti oxidative properties of the small peptides in vitro were studied. It was found that they could inhibit the auto oxidation of pyrogallol and the oxidation of hemoglobin. The hemolysis degree of erythrocyte caused by hydroxyl free radicals was decreased greatly, indicating a protective effect of the anti oxidative peptides on the cell membrane damage of erythrocyte.
基金supported by National Natural Science Foundation of China(No.81373274)Ph.D.Programs Foundation of Ministry of Education China(No.20120073110068)Shanghai Biomedical Supporting Funding(No.15431900600)
文摘6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.
基金supported by National Natural Sciences Foundation of China(No.81370230 and81570279)Natural Sciences Foundation of Hunan Province(No.2015JJ6118)+2 种基金Grant from the New Xiangya Talent Project of the Third Xiangya Hospital of Central South University(No.JJ201524)Medical Scientific Research Foundation of Guangdong Province(No.A2016392)Industry-University-Research Cooperation Innovation Major Project of Guangdong Province(No.1561000143)
文摘Background Taxifolin（Tax） is an essential natural antioxidant. Multiple studies have shown that Tax can protect cardiomyocytes from ischemia-reperfusion injury. However, the underlying mechanism is still unclear.Methods H9C2 cells were randomly divided into control, H_2O_2 group, Tax pretreatment group（Tax ＋ H_2O_2）;Tax effect group. Cell activity was detected by CCK-8 and the intracellular structure was observed by transmission electron microscopy. Autophagy was determine by Western blotting analysis of Beclin-1, Bcl-2 and PKC.Results Tax pretreatment significantly increased anti-apoptotic protein Bcl-2 and autophagy protein Beclin-1.Expression of PKC was inhibited by Tax. Conclusions Tax pretreatment could protect H9 C2 cells against H_2O_2-induced damage through the Bcl-2 and autophagy pathways.
文摘The anti-oxidation performance of 3,7-di-iso-octyl-phenothiazine was measured in group Ⅰ,Ⅱ and Ⅳ base oils by rotating pressure vessel oxidation testing(RPVOT),pressure differential scanning calorimetry(PDSC)and aging test,and its synergistic effect with 4,4′-di-iso-octyl-diphenylamine was examined.The results indicated that 3,7-di-iso-octyl-phenothiazine showed longer oxidation induction period and lower acid number increase than 4,4′-di-iso-octyl-diphenylamine,and their notable synergistic effect was observed.It was found that the anti-oxidation characteristics of the above-mentioned antioxidants were strongly affected by the composition of the corresponding base oil.
