Study on Chemical Constituents of Panax notoginseng Leaves

Panax notoginseng (Burk.) F. H. is a genuine medicinal material in Yunnan Province. As accessories, P. notoginseng leaves mainly contain protopanaxadiol saponins. The preliminary findings have indicated that P. notoginseng leaves contribute to its significant pharmacological effects and have been administrated to tranquilize and treat cancer and nerve injury. Saponins from P. notoginseng leaves were isolated and purified by different chromatographic methods, and the structures of 1-22 were elucidated mainly through comprehensive analyses of spectroscopic data. Moreover, the SH-SY5Y cells protection bioactivities of all isolated compounds were tested by establishing L-glutamate models for nerve cell injury. As a result, twenty-two saponins, including eight dammarane saponins, namely notoginsenosides SL₁-SL₈ (1-8), were identified as new compounds, together with fourteen known compounds, namely notoginsenoside NL-A₃ (9), ginsenoside Rc (10), gypenoside IX (11), gypenoside XVII (12), notoginsenoside Fc (13), quinquenoside L₃ (14), notoginsenoside NL-B₁ (15), notoginsenoside NL-C₂ (16), notoginsenoside NL-H₂ (17), notoginsenoside NL-H₁ (18), vina-ginsenoside R₁₃ (19), ginsenoside II (20), majoroside F₄ (21), and notoginsenoside LK₄ (22). Among them, notoginsenoside SL₁ (1), notoginsenoside SL₃ (3), notoginsenoside NL-A₃ (9), and ginsenoside Rc (10) showed slight protective effects against L-glutamate-induced nerve cell injury (30 µM).