A comparative study of the anti-oxidative and anti-diabetic potential of in vitro and in vivo root and leaf extracts of withania somnifera on streptozotocin induced diabetic rats

Abstract

Objective: The present investigation explores the possibilities of using the in vitro and in vivo root and leaf extracts of Withania somnifera for antidiabetic and anti-hyperlipidaemic effects on streptozotocin-induced diabetic rats. Methods: In vitro shoot cultures of Withania somnifera were raised by the axillary proliferation in nodal explants from a garden grown plant using Murashige and Skoog medium then in vitro raised roots and shoots were used for the anti-hyperglycemic and anti-hyperlipidaemic experiment. After 72 h of STZ administration, the fasting blood glucose levels were measured and the rats showing FBG level>220 mg/dl were considered to be diabetic and were used for the hyperglycemic study. In vitro and in vivo methanolic root and leaf extracts were orally administered daily to diabetic rats for eight weeks. After the treatment period, blood glucose and serum enzymes like aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total cholesterol, triglycerides, HDL-c high density lipoprotein-bound cholesterol, LDL-c low density lipoprotein-bound cholesterol, LDH, serum protein level, total phenolics and anti-oxidative analysis (DPPH and FRAP) were determined. Results: The levels of blood glucose, AST, ALT, ALP, LDH, HDL-c significantly increased by the use of in vitro methanolic root extracts compared to normal control rats. However, remarkable loss of total protein, albumin, albumin: globulin (A: G) ratio was reported in streptozotocin-induced diabetic rats by using in vitro root extracts. Methanolic in vitro root extract at the dose levels of 300 mg/kg body weight produced a significant decrease in fasting blood glucose (FBG) level by 102.65 with respect to initial fasting blood glucose level after 30 d of the treatment. In vitro root extract demonstrated highest DPPH and FRAP free radical scavenging activity, i.e. 86.55±1.77 and 48.87±2.55 than other extracts. Conclusion: It may be concluded that methanolic in vitro root extract W. somnifera at the dose (300 mg/kg) has more potent anti-hyperglycaemic activity than the other in vitro and in vivo extracts of leaf and root on streptozotocin induced diabetic rats and was also found to be similar in effect to that of the standard drug ‘Glibenclamide’.