银杏叶聚戊烯醇的分离纯化

Study on the separation and purification of polyprenols from ginkgo biloba leaves

组合采用石油醚索氏提取、碱性甲醇水解除杂和硅胶柱层析纯化的技术,建立了银杏叶聚戊烯醇(PPs)的分离纯化方法。石油醚索氏提取条件为:添加4倍银杏叶细粉量的60~90℃石油醚,于90℃索氏提取4 h,可完全提取出聚戊烯醇乙酸酯和银杏酸,其中聚戊烯醇乙酸酯(PPAs)的含量为16.4%;碱性甲醇水解除杂条件为:每克浸膏用15 mL石油醚溶解,添加3倍料液量的90%甲醇水溶液(内含4%NaOH),于45℃条件下、100 r/min搅拌水解2次、每次2 h,PPAs可完全水解成PPs,水解液石油醚相中PPs纯度可达35.9%,银杏酸可99.1%转移到甲醇相中被去除;硅胶柱层析纯化条件为:石油醚相脱溶剂至干得浸膏,每20 g硅胶上1 g浸膏,以石油醚/乙酸乙酯(体积比为9∶1)为洗脱液,以0.7 BV/h的流速洗脱并分部收集银杏叶聚戊烯醇。最终可得纯度≥95%的银杏叶聚戊烯醇,银杏叶中聚戊烯醇总得率为15.8 g/kg。

The techonologies of the separation and purification for polyprenols were established according to the methods of soxhlet extraction,hydrolysis with alkali methanol solution and silica gel colum chromatography.The soxhlet extraction conditions were chosed as follows:4 multiples petroleun ether(60-90℃) of Ginkgo Biloba Leaves,extraction tempreture 90℃.After extration for 4 h,mass fraction of the polyprenols acetates(PPAs) was 16.4%.The hydrolysis reaction conditions were determined according to 15 multiples 90% methanol solution(comprised of 4% NaOH) of extraction,reaction tempreture 45℃,reaction for 2 h each times.After hydrolysis for twice,mass fraction of the polyprenols(PPs) reached 35.9%.The conditions of the silica gel colum chromatography were established according to 20 g silica gel to 1 g hydrolysate,eluent was comprised of petroleun ether and ethyl acetate(9∶1 by volume),0.7 BV/h flow velocity.At last,the hydrolysis rate of PPAs to PPs was 100%,the purity of PPs product was over 95% and the product yield rate was 15.8 g/g Ginkgo biloba leaves powder.