Complementary Application of HSCCC and Semi-preparative HPLC for Rapid Separation of Phenylethanoid Glycosides from Penstemon digitalis

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.