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

Abstract

The chemical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity changes of ginsenoside Rb 1 -glycine and ginsenoside Rg 1 -glycine mixtures by Maillard reaction were investigated to identify the role of Maillard reaction in the increased antioxidant activity of ginseng by heat-processing. The DPPH radical scavenging activity of Rg 1 -glycine mixture was more strongly increased by heat-processing than that of Rb 1 -glycine mixture. From the analyses of ginsenosides, Rb 1 was gradually changed into 20(S)-Rg 3 , 20(R)-Rg 3 , Rk 1 and Rg 5 by heat-processing. Rg 1 was gradually changed into 20(S)-Rh 1 , 20(R)-Rh 1 , Rk 3 and Rh 4 by heat-processing. However, the generation of these less-polar ginsenosides was not related to the increased DPPH radical scavenging activity of Rb 1 -glycine and Rg 1 -glycine mixtures because their DPPH radical scavenging activities were already signifi cantly increased when dried at 50°C, which temperature induce no structural changes of ginsenosides. In the comparison of browning compound levels of Rg 1 -glycine and Rb 1 -glycine mixtures, the extents of Maillard reaction were positively correlated with their increased free radical scavenging activities. Based on the chemical and DPPH radical scavenging activity changes of Rg 1 -glycine and Rb 1 -glycine mixtures by heat-processing, we clearly identifi ed that the increased free radical scavenging activity of ginsenoside is mediated by the Maillard reaction between sugar moiety of ginsenoside and amino acid.

Increase in antioxidant effect of ginsenoside Re-alanine mixture by Maillard reaction

“…Previous studies over the 10 years have indicated that ginsenosides derived from Panax species target ROS, thereby may prevent several oxidative stress-induced diseases (reviewed in Jia, Zhao, & Liang, 2009 model experiments using ginsenosides (Rb 1 , Rb 2 and Rg 1 ) and amino acids to verify the important role of this reaction in the increased antioxidant effect of ginseng by heat-processing (Kang , Lee, Park, & Yokozawa, 2007;Lee et al, 2008;Yamabe et al, 2011). Our present study has shown for the first time the changes in structure and antioxidant activity of ginsenoside Re-alanine mixture by the Maillard reaction.…”

“…The samples (5 mg) were dissolved in 1 ml of distilled water (DW)-acetonitrile (1:1, v/v), and the absorbance at 420 nm was measured in a 1 cm glass cuvette using a UVVis spectrophotometer (UV-1200; Shimadzu, Kyoto, Japan). Measurement was repeated three times for each sample (Yamabe et al, 2011).…”

“…After drying at 50°C, un-treated and heat-processed ginsenoside Re-alanine mixtures at 120°C were prepared. The glucose-alanine mixture heat-processed at 120°C was also prepared to examine the effect of MRPs (Lee et al, 2008;Yamabe et al, 2011).…”

“…It has been heat-processed to improve its medicinal efficacies such as antioxidant and anticancer activities (Kang, Kim, Pyo, & Yokozawa, 2006a;Keum et al, 2000;Kim et al, 2000). Ginsenosides have been regarded as the main active components of P. ginseng, and we have demonstrated that the structural change of ginsenosides by heatprocessing is significantly related to its improved biological activities (Kang, Yokozawa,Yamabe,Kim, & Park 2007;Yamabe et al, 2011).…”

Chemical and Free Radical-scavenging Activity Changes of Ginsenoside Re by Maillard Reaction and Its Possible Use as a Renoprotective Agent

“…Ginsenosides have been regarded as the main active components of P. ginseng , and we have identified that the structural changes of ginsenosides by heat-processing are closely related to its increased free radical-scavenging activities [4,5]. In addition, the generation of Maillard reaction products (MRPs), although limited to the reaction between the glucosyl moieties separated from ginsenosides and glycine, is positively correlated with the free radical-scavenging activity [6].…”