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荧光法测定羟基自由基及中草药抗氧化性 总被引:1,自引:0,他引:1
L-苯丙氨酸本身具有较弱的荧光,在羟基自由基的作用下能产生较强的荧光,其激发波长和发射波长分别是277 nm和306 nm.很多中草药提取物可以清除溶液中的羟基自由基,从而使溶液的荧光增强程度降低.据此,建立了一种测定中草药抗氧化性的方法.研究了L-苯丙氨酸-Fe2 -H2O2体系产生羟基自由基的最佳条件,并测试了赤芍、钩藤、姜黄、炒蒺藜四种中草药水提物的抗氧化活性. 相似文献
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用L-苯丙氨基酸和5-[对-(4-溴丁氧基)苯基]-10,15,20-三苯基卟啉合成了一种新型尾式卟啉及其锌(Ⅱ)配合物,并通过质谱、红外、紫外光谱对其结构进行了表征,测试并研究了它们在4000~400cm~(-1)范围内的傅里叶变换红外光谱,对主要谱带进行了经验归属. 相似文献
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Synthesis of Protected Tetrapeptide, N-o-Ns-N (Me) - Val-N (Me) -Val-N ( Me ) -Val-N (Me) -Phe-O^tBu
The protected tetrapeptide, N-o-Ns-N ( Me ) -Val-N ( Me ) -Val-N ( Me ) -Val- N ( Me ) -Phe- OtBu, was prepared from L-valine and L-phenylalanine. Ted-butyl acetate and HClO4 were used to protect carbonyl group, o-nitrobenzenesulfonyl chloride and triethyl amine were used to protect amino group, and N-alkylation was finished with iodomethane. Then the protected amino acid was turned into acid chloride which was taken as coupling reagent. After 14 steps, such as protection, alkylation, deprotection and coupling, the protected tetrapeptide was obtained with a yield of 26.9%. The structures of intermediates and target compound were identified with NMR spectra and high resolution mass spectra. 相似文献
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