Studies on the absorption, distribution, excretion and metabolism of ginseng saponins. IV. Decomposition of ginsenoside-Rg1 and -Rb1 in the digestive tract of rats.

Abstract

The decomposition of ginsenoside-Rg1 and ginsenoside-Rb1 in the rat stomach and large intestine after oral administration was investigated. In the stomach, a part of ginsenoside-Rg1 was decomposed and six decomposition products were observed on a reversed phase thin-layer chromatogram (TLC). These six compounds were identical with those which were obtained on hydrolysis of ginsenoside-Rg1 under mild acidic conditions (with 0.1 N HCl, at 37°C). On the other hand, an unidentified deomposition product of ginsenoside-Rb1 was observed on the TLC of the stomach sample after the oral administration of Rb1 to rats. The product was different from the decomposition product formed by the hydrolysis of Rb1 under mild acidic conditions. In the large intestine, Rg1 was decomposed to ginsenoside-Rh1 and ginsenoside-F1 by tetracycline-susceptible bacteria and tetracycline-resistant bacteria, respectively. Ginsenoside-Rb1 was decomposed to ginsenoside-Rd and two unidentified products by enteric enzyme and tetracyclineresistant bacteria, respectively.