Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic a...Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.展开更多
目的:研究维生素E琥珀酸酯(vitamin E succinate,VES)是否可通过氧化应激来诱导胃癌细胞凋亡及其可能机制。方法:分别用5、10和20μg/ml的VES处理胃癌SGC-7901细胞24h,同时设阴性对照组和甘露醇(活性氧抑制剂)预处理组。通过流式细胞技...目的:研究维生素E琥珀酸酯(vitamin E succinate,VES)是否可通过氧化应激来诱导胃癌细胞凋亡及其可能机制。方法:分别用5、10和20μg/ml的VES处理胃癌SGC-7901细胞24h,同时设阴性对照组和甘露醇(活性氧抑制剂)预处理组。通过流式细胞技术、共聚焦技术和Western blot方法,检测了VES诱导SGC-7901细胞线粒体氧化损伤及细胞凋亡的情况,用相应的检测试剂盒检测细胞内活性氧和Ca2+含量变化情况。结果:不同浓度的VES对SGC-7901细胞均有诱导凋亡的作用。表现为随VES浓度的增加,SGC-7901细胞凋亡数量呈现增加的趋势,且SGC_7901细胞内活性氧含量及钙离子水平呈现增加的趋势,而线粒体膜电位逐渐下降。活性氧抑制剂甘露醇(1mmol/L)对VES诱导的胃癌细胞凋亡,和细胞内活性氧、钙浓度的增高及膜电位的降低均有显著抑制作用(P<0.05)。随VES浓度的增加,SGC_7901细胞内Bax蛋白的表达呈现上升的趋势,而Bcl-2蛋白的表达呈现下降趋势。甘露醇可显著降低胃癌SGC-7901细胞Bax蛋白的表达水平,同时增加Bcl-2蛋白的表达(P<0.05)。结论:VES可显著促进胃癌细胞凋亡,并且随着VES剂量的增加,VES诱导胃癌细胞凋亡的作用越强。细胞内活性氧含量增加、细胞内钙超载所导致的线粒体氧化损伤作用可能是VES诱导细胞凋亡的机制之一。展开更多
基金Supported by the Fundamental Research Funds for the Central Universities and the State Key Development Program for Basic Research of China(2007CB714304)
文摘Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.
文摘目的:研究维生素E琥珀酸酯(vitamin E succinate,VES)是否可通过氧化应激来诱导胃癌细胞凋亡及其可能机制。方法:分别用5、10和20μg/ml的VES处理胃癌SGC-7901细胞24h,同时设阴性对照组和甘露醇(活性氧抑制剂)预处理组。通过流式细胞技术、共聚焦技术和Western blot方法,检测了VES诱导SGC-7901细胞线粒体氧化损伤及细胞凋亡的情况,用相应的检测试剂盒检测细胞内活性氧和Ca2+含量变化情况。结果:不同浓度的VES对SGC-7901细胞均有诱导凋亡的作用。表现为随VES浓度的增加,SGC-7901细胞凋亡数量呈现增加的趋势,且SGC_7901细胞内活性氧含量及钙离子水平呈现增加的趋势,而线粒体膜电位逐渐下降。活性氧抑制剂甘露醇(1mmol/L)对VES诱导的胃癌细胞凋亡,和细胞内活性氧、钙浓度的增高及膜电位的降低均有显著抑制作用(P<0.05)。随VES浓度的增加,SGC_7901细胞内Bax蛋白的表达呈现上升的趋势,而Bcl-2蛋白的表达呈现下降趋势。甘露醇可显著降低胃癌SGC-7901细胞Bax蛋白的表达水平,同时增加Bcl-2蛋白的表达(P<0.05)。结论:VES可显著促进胃癌细胞凋亡,并且随着VES剂量的增加,VES诱导胃癌细胞凋亡的作用越强。细胞内活性氧含量增加、细胞内钙超载所导致的线粒体氧化损伤作用可能是VES诱导细胞凋亡的机制之一。
