Contrasting actions of ginsenosides Rb1 and Rg1 on glucose tolerance in rats
Rungchai Chaunchaiyakul1, Naruemon Leelayuwat2, Jin-Fu Wu3, Chih-Yang Huang4, Chia-Hua Kuo5
1 Faculty of Sports Science and Technology, Mahidol University, Nakhonpathom, Thailand; Laboratory of Exercise Biochemistry, University of Taipei, Taipei, Taiwan
2 Exercise and Sport Sciences Development and Research Group, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
3 Laboratory of Regenerative Medicine in Sports Science, School of Physical Education & Sports Science, South China Normal University, Taichung, Taiwan
4 Graduate Institute of Basic Medicine, China Medical University, Taichung, Taiwan
5 Laboratory of Exercise Biochemistry, University of Taipei, Taipei, Taiwan
Prof. Chia-Hua Kuo
Laboratory of Exercise Biochemistry, University of Taipei, 101, Section 2, Jhong Cheng Road, Shihlin District, Taipei 111
Source of Support: This study was supported by grants from the Ministry of Science and Technology, Taiwan; Nuliv Sciences, CA, USA; and University of Taipei, Taipei, Taiwan., Conflict of Interest: This work was funded to develop a supplement for Nuliv Science, Taiwan, and the USA.
Ginsenoside profile of Panax ginseng is changing with season and cultivated soil. Yet, dose-response relationship of main ginsenosides on metabolic measures has not been documented in vivo. Here, we examined glucose and insulin responses after an oral glucose challenge (0.5 g/kg body weight) at various doses (0.01, 0.1, 1, and 10 mg/kg of body weight) under acute and chronic Rb1 and Rg1 supplemented conditions. The results show that Rb1 (0.01 and 0.1 mg/kg body weight) increased, whereas Rg1 (0.01 mg/kg body weight) decreased postprandial glucose levels compared with the Vehicle group (P < 0.05). This contrasting effect reduced as dose increased. Both Rb1 and Rg1 decreased the mitochondrial enzyme citrate synthase activity (P < 0.05) together with decreases in glycogen content in red gastrocnemius muscle and body temperature at low doses (P < 0.05), compared with the Vehicle group. These differences also diminished as dosage increases. For reliable ginseng research, dose standardization on Rg1 and Rb1 is essential based on their opposing action and peculiar dose-response relationship. Both major ginsenosides may influence dynamics of mitochondria turnover and alter muscle metabolism.