ABSTRACT
Objective: A new, environment-friendly and efficient method for the preparation of rare ginsenoside Rg6, F4, Rk3, and Rh4 was established, which provides a theoretical basis for preparing rare ginsenosides. Methods: Rare ginsenoside was prepared by hydrolyzing ginsenoside Re using aspartic acid as the catalyst, through semi preparative HPLC, the target compounds Rg6, F4, Rk3, and Rh4 were rapidly separated from the degradation products, quantitative analysis, and structure identification by HPLC and NMR. Results: Ginsenoside Re was hydrolyzed by aspartic acid according to the ratio 10∶1 at 120℃ for 1 h, the conversion rate of ginsenoside Re was 100%, the yields of rare ginsenoside Rg6, F4, Rk3, and Rh4 were 11.2%, 13.1%, 20.6%, and 24.3%, respectively, and the purity of the four compounds were all above 99%. Conclusion: The method is simple, low-cost, and non-pollution for environment, the research has important application value for the development of green environmental protection of rare ginsenosides drugs and health food.
ABSTRACT
Objective: Echinacoside and verbascoside are known for their excellent neuroprotective, anti-inflammatory, and anti-oxidative activities, therefore large amount of pure compounds are urgently needed as authentic standards for various in vivo and in vitro studies. Nowadays, they are abundenty extracted from endangered Cistanche spp. Phytochemical studies revealed that Penstemon spp., comprising about 280 species, were rich natural sources for the exploitation and large scale preparation of phenylethanoid glycosides. Thus, rapid isolation and purification of various phenylethanoid glycosides from Penstemon spp. were necessary. Methods: The crude extract of P. digitalis was first enriched by AB-8, and then the high-speed counter-current chromatography (HSCCC) combined with semi-preparative high performance liquid chromatography (HPLC) method was adopted to isolate and purify echinacoside and verbascoside. Results: Eventually, verbascoside (67.2 mg) with the purity of 92.6% and echinacoside (3.96 mg) with the purity of 98.9% were obtained from 5 g powdered leaves of P. digitalis. Conclusion: The present mode of HSCCC coupled with semi-preparative HPLC could be a powerful method for the rapid isolation and purification of other phenylethanoid glycosides. © 2013 Tianjin Press of Chinese Herbal Medicines.