The present study was conducted to determine the antihyperglycemic as well as antioxidative effects of ‘
Diashis’, a polyherbal formulation, in STZ-induced diabetic male albino rats. The effects were compared with those of the standard antidiabetic drug, ‘Glibenclamide’.
Diashis is an Ayurvedic polyherbal formulation that is widely used for the treatment of diabetes in some areas of West Bengal, however, its mechanism of antidiabetic action is not known. Hence, we studied fasting blood glucose (FBG) levels along with glycogen content in liver and skeletal muscle, and the activities of some important carbohydrate metabolism enzymes. Moreover, we have also assessed the stress-induced oxidative status in the livers of the experimental groups because diabetes has a strong association with oxidative injury.[
29]
This study selected the STZ-induced diabetic rat as an experimental model because it is commonly used model to study the effects of antidiabetogenic agents.[
30,
31] Streptozotocin-induced diabetes has been demonstrated in this study by the decrease in the activities of hexokinase and glucose-6-phosphate dehydrogenase as these enzymes are regulated by insulin.[
32] These results are consistent with those already reported by our previous publication.[
33] Diabetes induction has been strengthened further by the elevated activity of glucose-6-phosphatase as this is under the negative control of insulin.[
34] Treatment with ‘
Diashis’ or ‘Glibenclamide’ resulted in a significant (
P < 0.001) recovery in the activities of the said enzymes which may be due to the recovery in plasma insulin levels. Another possibility for the decrease in the activities of hexokinase and glucose-6-phosphate dehydrogenase in diabetes may be due to diabetes induced-oxidative injury as free radicals are scavengers of structural and functional protein including enzyme in cells.[
35] This has been reflected here by the significant decrease in the activities of key antioxidant enzymes like catalase (CAT), peroxidase (Px), and glutathione-
S-transferase (GST) in the liver.[
36] The decrease in the activities of antioxidant enzymes in diabetes may be due to low levels of insulin or due to high levels of advanced glycated end products.[
37,
38] This hypothesis has been strengthened by the elevation in the levels of end products of free radicals like TBARS and CD, which has also been supported by our previous publication and also by others.[
39,
40] Significant recovery in the activities of antioxidant enzymes due to ‘
Diashis’ may be due to correction in blood glucose levels or by plasma insulin through ß-cells stimulating effect of phyto-ingredient(s) present in ‘
Diashis’ as claimed by others by using others plant parts.[
41] The correction in diabetes induced-oxidative injury by ‘
Diashis’ was supported by the decrease in the levels of CD and TBARS, the end products of free radical generation.[
42]
The antidiabetic effect of
Diashis has been further supported here by the measurement of glycated hemoglobin (HbA
1c) as proposed by others and by our previous reports.[
43,
44] Treatment with ‘
Diashis’ or ‘Glibenclamide’ in diabetic rats resulted in a significant recovery in hemoglobin and HbA
1c levels, which may be due to recovery in plasma glucose towards the control levels.
Quantification of glycogen in the liver and skeletal muscle further confirms the efficacy of ‘
Diashis’ for the recovery of diabetes, which, in turn, supports the insulinotropic effect of ‘
Diashis’, as insulin is the main regulator of glycogen content in liver and skeletal muscle.[
45]
This polyherbal formulation has no general toxic effect as body weights remain similar to those in the control and the ‘Diashis’-treated groups. Moreover, there was no change in the activities of serum GOT and GPT in the polyherbal formulation-treated group which also illustrates the nontoxic effect of ‘Diashis’.
In conclusion, the polyherbal formulation ‘Diashis’ appears to compare favourably with glubln alamide drug.