Study on the Hydroxyl Radical Scavenging Activity Changes of Ginseng and Ginsenoside-Rb2 by Heat Processing

Abstract

Traditional herbal medicines have been processed to enhance their therapeutic effects, remove or reduce toxicity and side effects, and facilitate preparation and storage. In addition, the increased biological activities have been thought to be closely related to the compounds which are modified through processing.1-3) Therefore, there has been a growing interest in the bioactive constituents of herbal drugs modified by processing. [4][5][6] The root of ginseng, Panax ginseng C.A. MEYER (Araliaceae), has been heat processed to make white ginseng (WG, roots dried after peeling) and red ginseng (RG, steamed at 98-100°C and dried ginseng roots without peeling) for consumption. Especially, RG is more common as a functional food than WG in Asian countries, because steaming induces a change in the chemical constituents and enhances the biological activities of ginseng. [7][8][9][10] Recently, a method to increase the RG-specific ginsenosides by steaming WG at a higher temperature than RG was developed.2,11) This heat processed ginseng is termed sun ginseng (SG), and we have been investigating its enhanced free radical scavenging activity compared to conventional ginsengs and its active constituents.Phenolic compounds and maltol were responsible for the increased free radical scavenging activities of SG. In addition, Maillard reaction products (MRPs) were also thought to be related to the increased antioxidant activity of ginseng by heat processing, 5,6) because the Maillard reaction has been thought to be the major source correlated with increased efficacy by heat processing in various crude drugs or foods. 12,13) On the other hand, ginsenoside is one of the easily changeable components of ginseng by heat processing, 2,14) but heat processing-induced chemical and activity changes of ginsenosides considering the Maillard reaction have not yet been fully elucidated. In addition, the contents of less-polar ginsenosides Rg 3 , Rk 1 , Rg 5 , and maltol are known to increase by heat processing, and these compounds are supposed to be produced by the deglycosylation of diol-type ginsenosides and the Maillard reaction in ginseng by steaming. 6,14) Therefore, there is a need to investigate the structure and activity changes of isolated ginsenosides by heat processing with amino acids.In this study, we investigated the hydroxyl radical (· OH) scavenging activity changes of ginsengs and ginsenoside-Rb 2 (Rb 2 ) by heat processing using an electron spin resonance spectrometer (ESR). No report has compared the · OH scavenging activities of WG, RG, and SG using ESR, and ESR is thought as a versatile tool to detect free radicals even with slightly insoluble ginsenosides in suspension. In addition, Rb 2 , a well known diol-type triterpene glycoside that exists abundantly in Panax ginseng, was steamed with glycine, a frequently used amino acid in the Maillard reaction model system, 15) and the chemical and · OH scavenging activity changes were analyzed and compared. Shillim-Dong, Kwanak-gu, Seoul 151-742, Korea. Received October 7, 20...

The Chemical and 1,1-Diphenyl-2-Picrylhydrazyl Radical Scavenging Activity Changes of Ginsenosides Rb1and Rg1by Maillard Reaction

“…1 [17][18][19][20]. The critical roles of the Maillard reaction were confi rmed and supported by the following lines of observations: Firstly, the generation of Maillard reaction products (MRPs), based on the extent of browning, was positively correlated with the hydroxyl radical (-OH) scavenging activity [20].…”

“…RG was made by steaming WG at 100°C and 0.03 megapascal (MPa) for 3 h, and drying at 50°C for 3 days. HPG was made by steaming WG at 120°C and 0.11 MPa for 3 h, and drying at 50°C for 3 days [18]. The three ginsengs were ground to pass an 80 mesh sieve and extracted under refl ux with MeOH three times at 70°C for 2 h, fi ltered through fi lter paper (Advantec, Tokyo, Japan), and the solvent was evaporated in vacuo to give a MeOH extract with a yield of 19%, by weight, of the original ginseng powder.…”

“…The same amounts (w/w) of each ginsenosides (Rb 1 and Rg 1 ) and glycine, a frequently used amino acid in Maillard reaction model experiment, were steamed together at 120°C for 3 h as reported previously [18,21]. After drying at 50°C for 3 days, un-treated and heat processed Rb 1 -gylcine mixtures at 120°C were prepared.…”

“…The important roles of Maillard reaction in the heatprocessing of ginsenosides has been identifi ed with dioltype gisenosides in our previous studies [18,20,21]. However, little is known about the Maillard reaction of triol-type ginsenosides.…”

Ginsenoside-Rg5 treatment inhibits apoptosis of chondrocytes and degradation of cartilage matrix in a rat model of osteoarthritis

“…Ginseng has a long traditional medicinal importance for the treatment of cancers, stress and diabetes (14). Ginsenoside-Rg5 obtained by the processing of ginseng has shown promising anticancer, anti-inflammatory and anti-aging properties (15)(16)(17). There are several reports which demonstrate the activity of ginsenoside-Rg5 against cancer (18,19), dermatis (20), inflammation (21) and neurotrophic disorders (22).…”