Anti-diabetic properties of different fractions of Korean red ginseng

Abstract

Ethnopharmacological relevance: Korean red ginseng (KRG) has been traditionally used to treat diabetes. Ginsenosides are considered as the major bioactive components mediating anti-diabetic effects of KRG. However, considering that ginsenosides account for only about 3-4% of ginsengs, other fractions of KRG may also carry potential anti-diabetic effects. There is no study reporting the differentiated effects of ginsenosides (Spn) and non-saponin fractions (NSpn) of KRG on glycemic control. Aim of the study: We investigated the effects of KRG, Spn, and NSpn on the indications of glycemic control and sought to elucidate physiological factors contributing their effects. Materials and methods: Human T2DM mimicking Nagoya-Shibata-Yasuda (NSY/hos) mice were given KRG, Spn, or NSpn admixed in rodent diet at 200 mg/kg/day for 24 weeks. Glycemic and obesity indications, blood lipid profile, systematic and local oxidative stress markers in metabolically important organs, and systematic inflammatory markers were assessed. Molecular assessments associated with glycemic control in liver and skeletal muscle were further performed. Results: KRG attenuated deterioration in glucose homeostasis as evidenced by significantly lower fasting blood glucose from 22nd week and AUC during GTT at the end of the experiment compare to control. Spn enhanced insulin secretion in response to glucose stimulation and reduced protein level of glycogen phosphorylase in liver. On the other hand, NSpn ameliorated oxidative stress and inflammation. Some beneficial effects of Spn and NSpn were reflected in KRG treated mice. KRG also attenuated the accumulation of malondialdehyde in skeletal muscle and, accordingly, enhanced insulin responsiveness compare to control. Conclusion: Anti-diabetic properties of KRG are not solely determined by the contents of ginsenosides but the harmonic functions of its different fractions.