Response surface methodology based development of an optimized polyherbal formulation and evaluation of its anti-diabetic and anti-obesity potential in high-fat diet-induced obese mice

Abstract

Background and aim: The seeds of Nelumbo nucifera, Chenopodium quinoa and Salvia hispanica are known as super foods due to their various therapeutic properties. The present study aimed to develop an optimized polyherbal formulation from edible seeds aqueous extract and to evaluate its anti-diabetic and lipase inhibitory effect on diet-induced obese diabetic mice.

Experimental procedure: Response surface methodology based various formulations were evaluated for their potent anti-diabetic, lipase-inhibitory and antioxidant activities. Acute toxicity of the best optimized formulation was conducted. The mice were fed a high fat diet for 10 weeks resulting in hyperglycemia and obesity. Oral tolerance tests (sucrose, starch and lipid) of the formulation were performed. The mice were supplemented with different doses (125, 250 and 500 mg/kg) of the formulation for 6 weeks. The body weight and blood glucose level were monitored on a weekly basis. Finally, histological alterations and lipid profiles were analysed.

Results and conclusion: The formulation containing equal concentration (1.5 mg/ml) of each seed extract showed maximum bioactivities. The formulation was found to be safe during toxicity assay. The tolerance tests supported the anti-diabetic and anti-obesity effect. Higher dose (500 mg/kg) of the formulation significantly (p < 0.01) lowered elevated fasting blood glucose, lipid indices and ameliorated the histological alterations in liver, kidney and pancreas caused by high fat diet. We demonstrated for the first time that the developed aqueous extract optimized formulation possess anti-diabetic and anti-obesity potential and thus could be used as adjuvant therapy for holistic management of type 2 diabetes mellitus.

Keywords: Anti-diabetic activity; Anti-obesity activity; Chenopodium quinoa; Nelumbo nucifera; Optimized polyherbal formulation; Salvia hispanica.

Graphical abstract

Fig. 1

Response surface plots (3D) showing the mutual interactions of (A) S. hispanica and C. quinoa (B) S. hispanica and N. nucifera and (C) C. quinoa and N. nucifera on A) α-amylase, B) α-glucosidase, C) lipase inhibition and D) DPPH and E) ABTS^●+ scavenging.

Fig. 2

Effect of PF on (A) oral starch tolerance and (B) oral sucrose tolerance over 2 h and C. oral lipid tolerance over a period of 4 h in DIO mice. Values were expressed as mean ± SEM (n = 6); compared with the control. PF= Polyherbal formulation.

Fig. 3

Effect of PF on blood glucose level (mg/dL) in DIO mice. ∗ Values are expressed as mean ± SEM (n = 6); compared with the control. Data were analysed with One way ANOVA followed by post hoc analysis (Dunnets multiple comparison test). Values are statistically significant at p < 0.001. PF= Polyherbal formulation.

Fig. 4

Effect of PF treatment on body weight of mice during 6 weeks. ∗ Values are expressed as mean ± SEM (n = 6); compared with the control. Data were analysed with One way ANOVA followed by post hoc analysis (Dunnets multiple comparison test). Values are statistically significant at p < 0.001. PF= Polyherbal formulation.

Fig. 5

Histological examination of liver, kidney and pancreatic tissue (magnification × 100) after hematoxylin and eosin staining. Liver: Normal hepatocytes in control, glibenclamide and PF treated groups (low, middle, and high) are indicated by orange arrow. Whereas lipid droplets in HFD group, glibenclamide and PF treated groups are indicated by green arrow. HFD= High Fat Diet; PF= Polyherbal Formulation. Kidney: Normal glomerulus is shown by asterisk mark in control, glibenclamide and PF treated groups (low, middle, and high). Increased bowman's space in HFD group is shown by orange arrows. Pancreas: Arrows indicates acini in all studied groups, whereas asterisk mark indicates islet of langerhans in pancreas of control, glibenclamide and PF treated groups (125, 250, 500 mg/kg). The large view of changes has been shown with the help of inset (scale bar = 20 μm). A).