Effect of Panax notoginsenoside Rg1 on bidirectional regulation of blood glucose level in mice

Abstract

Panax notoginseng saponin (PNS) is one of the key bioactive components of dry root and rhizome of Panax notoginseng (Burk.), a well known as Tianqi in Traditional Chinese Medicine (TCM). Although PNS has been shown to possess various pharmacological activities, such as being antithrombotic, neuroprotective, anti-inflammatory and hypolipidemic, etc.,  its effects on blood glucose levels have not been well documented but for some preliminary reports. It deserves a detailed in vivo investigation in animal model. Thus, to investigate the bi-directional regulation of ginsenoside Rgl (Rg1) on blood glucose in mice, Rg1 with high purity was prepared from panax notoginseng saponins by normal phase silica gel column chromatography and reverse phase C18 preparative chromatography. Normal 4-week-old mice were randomly divided into normal control group, normal control group with Rg1, glucose gavage control group, glucose gavage control group with Rg1, insulin treated control group and overnight fasting control group with or without Rg1 (n = 10). The mice in the control group were intragastrically administered with PBS solution, and the mice in the Rg1 groups were intragastrically administered with Rg1 once a day at the doses of 0.5, 1.0 and 1.5 mg/kg for consecutive 7 days. After the last drug, blood glucose (BG) levels were measured at 0.5 (30 min) and 1 h after administration using a simultaneous automatic biochemical analyzer to observe the effect of Rg1 on BG levels. Compared with the model group, Rg1 significantly decreased the BG levels of hyperglycemic mice induced by glucose gavage (P <0.05), significantly increased the BG level of overnight fasted mice (P <0.05), and had no significant effects on the normal group of mice. Panax notoginseng saponin Rgl has a significant bidirectional regulatory effect on glucose levels in mice. When the blood glucose of mice increases, intragastric administration of Rg1 can effectively reduce the blood glucose; conversely, when the blood glucose of mice is low, Rg1 can effectively increase the blood glucose value.