Biol. Pharm. Bull. 30(10) 1975—1978 (2007)

aceae), has been heat-processed to improve its medicinal efficacies in Korea based on the long history of ethnopharmacological evidence. Although the increasing body of evidence supports that Maillard reaction products (MRPs) are implicated in the increased activity by heat treatment in various crude drugs or foods, the effect of Maillard reaction on the active components of ginseng and biological activities have not yet been fully elucidated. Ginsenosides have been regarded as the main active components responsible for the pharmacological activities of ginseng, and are well-known to be deglycosylated by heat-processing. The sugar moieties of ginsenosides can be a source of MRPs with amino acids contained in ginseng during heat-processing, and research on the Maillard reaction of ginsenosides is thought to be beneficial to understand the complex structural changes of ginsenosides brought about during the heat-processing of ginseng. As one of the major ginsenosides contained in Panax ginseng, ginsenoside Rb1 (Rb1) is a diol-type triterpene glycoside, and it is known to exhibit anti-inflammatory, antioxidative, analgesic, and antipyretic effects, promote the synthesis of protein, nucleic acid, and cholesterol, and inhibit neural lipid breakdown. At the same time, the heat-processing-induced deglycosylation of two glucose molecules at carbon-20 of Rb1 has been well documented. 3,5,7,11) Therefore, Rb1 was used as a target ginsenoside to study a Maillard reaction model experiment in this study. To identify the effects of amino acids on the heat stability or structural changes of Rb1, Rb1 was heat-processed with or without the same amount of glycine or L-arginine, because glycine is a frequently used amino acid in Maillard reaction model experiments and L-arginine is the most abundant amino acid in Panax ginseng. In addition, HPLC and GCMS were used for component analyses of samples.