Preparation and Characterization of a Standardized Anticonvulsant Ginseng Rb Extract from Panax quinquefolius L.

Abstract

A ginseng Rb extract (GRbE) containing three major ingredients of ginsenoside Rb1 (G-Rb1), ginsenoside Rb3 (G-Rb3) and ginsenoside Rd (G-Rd) has been shown to have anticonvulsant and neuroprotective activity. As such, suffi- cient characterization and standardization of this active GRbE are demanded to facilitate an ongoing preclinical investiga- tion on its potential for the treatment of epilepsy. In the investigation, the methods for generating the active GRbE and isolating G-Rb1, G-Rb3, and G-Rd in large scale from Panax quinquefolius are described. The chemical profile of GRbE was characterized by identifying the structure of the individual ingredients using NMR, and the concentration of individ- ual ingredients was determined using HPLC. This study demonstrates the application of the established methods for re- producibly generating anticonvulsant GRbE, which is enriched in five panaxadiol glycosides of G-Rb1, ginsenoside Rb2 (G-Rb2), G-Rb3, ginsenoside Rc (G-Rc), and G-Rd with total ginsenosides over 90%, and for purifying G-Rb1, G-Gb3 and G-Rd with purity of 97.9%, 96.6% and 98.6%, respectively.