【作者】 李琪；

【导师】 张宏；

【作者基本信息】 四川师范大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 枇杷花系蔷薇科植物枇杷Eiobotrya.japonica(Thumb.)Lindl.之花。枇杷叶是一种常用中药,关于其化学成分及生物活性研究较多,但对于枇杷花的研究甚少,有关成分的抑菌及抗肿瘤生物活性的研究尚未报道。因此本文对枇杷花的化学成分及生物活性进行了初步研究。对枇杷花采用溶剂系统提取法,分为乙酸乙酯部分、95%乙醇部分、50%乙醇部分和水层四个部分,对这四个部分进行黄酮显色鉴别及含量测定,发现黄酮主要集中于50%乙醇部分,各部分的黄酮类别有所差异,但主要有黄酮类、黄酮醇类及二氢黄酮类化合物。本实验对枇杷花的乙酸乙酯提取部分采用硅胶柱层析、反相柱层析、Sephadex LH-20凝胶柱层析,结合薄层色谱、半制备色谱进行多次分离纯化与重结晶,从中分离得到了7个化合物,其中化合物7为两种单一化合物组成的混合物;利用核磁共振(NMR)、质谱(MS)等现代化分析测试手段测定其化学结构,经过波谱分析、理化常数及文献检索,鉴定了这些化合物的结构,分别为:β-谷甾醇(1)、齐墩果酸(2)、熊果酸(3)、3β,19α-二羟基-4-醛基-乌索-12-烯-28-酸(4)、β-胡萝卜苷(5)、槲皮素-3-O-β-D-半乳糖苷(6)、2α-羟基乌索酸与2α-羟基齐墩果酸(7)。其中化合物1、4、5、6、7为首次从枇杷花中分离得到。在生物活性方面,采用纸片扩散法和MTT法对枇杷花乙酸乙酯层分离得到的片段以及单一化合物进行了抑菌、抗肿瘤细胞的生物活性实验。实验表明,乙酸乙酯层分离的片段及化合物对大肠杆菌、金黄色葡萄球菌的抑菌作用很弱;除化合物6外,对白色念珠菌均具有不同程度的抑制作用,其中化合物2、4、5、7的抑菌效果优于阳性对照组。MTT实验中,片段E2-2-1及化合物2、3、7对白血病细胞K562有较好的抑制效果,且为浓度依赖性抑制作用,抑制癌细胞K562生长作用最强的化合物3,剂量为20μg/ml时,抑制率达91.96%。根据单一化合物对抗肿瘤K562活性的研究,初步确定该植物抗肿瘤K562的主要活性成分是三萜类化合物。更多还原

【Abstract】 Loquat flower is the flower of Eriobotrya japonica which belongs to Rosaseae category. Loquat leaf is a widely used Chinese medicine which has been much studied about its chemical components and biological activities. However, the reports of loquat flower are scarce and there is no report about its components and biological activities. Therefore,the dissertation preliminary study on the chemical components and biological activities of loquat flower.The loquat flower was extracted with systematic solvents, such as ethyl acetate, 95% ethanol, 50% ethanol and water. Flavonoids were identified and their contents determined in those extractives. Flovonoids were mainly contained in the 50% ethanol extractive. They are mainly flavones, flavanols, and flavonvones.In our experiment, the compounds in ethyl acetate extractive of loquat flower were separated and purified with column chromatography on silica gel, C18 and sephadex LH-20 gel, TLC, semipreparative chromatography and recrystallization. Seven components were separated and their structures were identified using NMR and MS and their physical &chemical constants were determined. They areβ-sitostero (l), Oleanic acid (2), Ursolic acid (3), 3β,19α-dihydroxyursolic-4-aldehyde-12-en-28-acid (4),β-daucosteriol (5), quercetin-3-O-α-L-galactoside(6), 2α-hydroxyursolic acid and 2α- maslinic acid (7). Among them, compound 1, 4, 5, 6 and 7 are first time separated from this plant.The antibacterial and antineoplastic effects of the compounds and extractive fractions were measured by Kirby-Bauer and MTT method. Our experiment indicated that the ethyl acetate extractive had poor antibiotic activities on Escherichiacoli and Staphylococcus aureus; compounds and extractive fractions except compound 6 had different antibiotic activities on Candidaabbicans. Compound 2, 4, 5 and 7 were better than the positive comparison. Section E2-2-1 and compound 2, 3, 7 were fairly effective to prohibit leukemia cell K562, the effect depending on their concentration. Compound 3 has an inhibitive rate of 91.96% to leukemia cell K562 in a 20μg/ml concentration. Triperpenoids were discovered as the main anti-tumor active component on K562 in this plant.更多还原