匙羹藤叶总皂苷的分光光度法测定

Spectrophotometry determination of total saponins in leaves of Gymnema sylvestre(Retz.)Schult.

目的:建立匙羹藤叶总皂苷快速、简便的分光光度分析方法。方法:以结构类似物甘草酸单铵盐为对照品,香草醛-冰醋酸和高氯酸混合液为显色剂,采用分光光度法于545 nm 处测定匙羹藤叶总皂苷溶液中总皂苷的含量。结果:甘草酸单铵盐在40～160μg范围内线性良好,回归方程为 A=0.0006m+0.3305(r=0.9960),平均回收率为101.7%,RSD=2.6%(n=5)。结论:该方法快速、简便,精密度和稳定性较好,可用于缺乏匙羹藤酸对照品时匙羹藤叶总皂苷的含量测定。

Objective ： To establish a fast, simple and convenient spectrophotometry for the analysis of total saponins in leaves of Cymnema sylvestre. Methods：Gymnemic acid and glycyrrhizic acid have the similar structure and relative molecular mass. When monoammonium glycyrrhizinate and gymnemic acid were dealt with mixed liquid of vanilin -glacial acetic acid and perchlorate, they would show the same colour with maximum absorption at 545 nm, so monoammonium glycyrrhizinate was chosen as contrast. The content of total saponins solution from leaves of Gymnema sylvestre was determined by spectrophotometry. Results： The linear range was between 40 - 160 μg, the correlation was 0. 9960, the recovery was 101.7 %, RSD was 2. 6% （n = 5 ）. Conclusion：This method is fast, simple and convenient, and has better accuracy and stability. So it can be used to determine the content of total saponins solution from leaves of Gymnema sylvestre when no gymnenmic acids can be obtained.