Effect of co-administration of metformin and extracts of Costus pictus D.Don leaves on alloxan-induced diabetes in rats

Abstract

Background and aim: The present study evaluates the antidiabetic effects of aqueous (CPAQ) and methanolic (CPME) extract of Costus pictus D. Don singly and/or in combination with metformin in alloxan-induced diabetic rats.

Experimental procedure: CPAQ and CPME (400 mg/kg dose), metformin (120 mg/kg) and two different combinations of plant extracts and metformin (200 + 60 mg/kg and 400 mg/kg + 60 mg/kg) were orally given to alloxan-induced diabetic rats for 21 days. At 0, 7, 14, and 21 days, body weight and blood glucose levels were measured.

Results and conclusion: After 21 days of treatment, biochemical profiling and histopathology analysis were carried out. CPAQ and CPME, when administrated separately, could decrease blood glucose levels (P ≤ 0.05). CPME showed more promising results (P ≤ 0.05) compared to the diabetic control group. Extracts co-administrated with metformin showed dose-dependent significant recovery of hypoglycemic activity of metformin. Fasting blood glucose levels, body weight, protein, and lipid profile of the treatment group were compared to the diabetic and normal control groups. Animal groups co-administered with CPME and metformin showed more significant effects on the recovery of tissue damages. The synergistic effect of plant extracts with metformin has positive effects on all the parameters and enhanced the efficiency and reduction of blood glucose levels.

Keywords: Costaceae; Histopathology; Hypoglycaemia; Insulin; Synergistic.

Graphical abstract

Fig. 1

Effect of Oral administration of Costus pictus methanolic and aqueous leaf extracts and their co-administration with metformin on glycaemia (mg/dl) after raising oral administration of glucose (2 g/kg b.wt), ∗Values are mean of five replicates ± Standard Error of Mean (SEM) The same superscript down the column denotes no significant difference (P ≤ 0.05). Normal = Normal Control; MET = Metformin-treated group; = Group treated with 120 mg/kg b.wt Metformin; CPAQ400 = Group treated wit 400 mg/kg b.wt of aqueous C. pictus; CPME400 = Group treated with 400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Group treated with 200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin; CPME200+MET = Group treated with 200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin; CPAQ400+MET = Group treated with 400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Group treated with 400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin.

Fig. 2

Serum Insulin levels in experimental animals after 21 days of treatment. Data are means of five replicates ± Standard error of the mean (SEM); ns = No significant difference; different superscripts denote significant different (P ≤ 0.05). Normal = Normal Control; Diabetic = Diabetic Control; MET = Diabetic +120 mg/kg b.wt Metformin; CPAQ400 = Diabetic+400 mg/kg b.wt of aqueous C. pictus; CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin).

Fig. 3

Determination of average weight of the experimental animals (A); Percentage weight loss of the diabetic treated and non-treated groups after 21 days of treatment (B); Average weight of rat organs (C); and the rat organ to body weight ratio (D) after treatment with standard drugs (Metformin) and Costus pictus extracts in comparison with the normal group. Data are means of five replicates ± Standard error of the mean (SEM); ns = No significant difference; different superscripts denote significant different (P ≤ 0.05). Normal = Normal Control; Diabetic = Diabetic Control; MET = Diabetic +120 mg/kg b.wt Metformin; CPAQ400 = Diabetic+400 mg/kg b.wt of aqueous C. pictus; CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); NWL: No weight loss.

Fig. 4

Average serum protein profile. Total Protein (A); Total Albumin Concentration (B); Globulin Concentration (C); Creatinine Concentration (D); Concentration of Urea (E); Alkaline Phosphatase-ALP (F); Serum Glutamic Pyruvic Transaminase (SGPT) also known as Alanine aminotransferase (G); and Serum Glutamic Oxaloacetate Transaminase (SGOT) also known as Aspartate aminotransferase (H) concentrations after 21 days of treatment with various formulations of Costus pictus. Data are means of five replicates ± Standard error of the mean (SEM); ns = No significant difference; different superscripts denote significant different (P ≤ 0.05). Normal = Normal Control; Diabetic = Diabetic Control; MET = Diabetic +120 mg/kg b.wt Metformin; CPAQ400 = Diabetic+400 mg/kg b.wt of aqueous C. pictus; CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin).

Fig. 5

Histopathology of the pancreas. Normal: Pancreas of the Normal animal showing normal histology of the pancreas tissues; Diabetic: Pancreas of the Diabetic non-treated animal showing destroyed, diminished size and shape of β-cells and damaged acinar cells with an abnormal structure of islet of Langerhans (yellow arrow), and disorganized interlobular duct (blue arrow); MET: Pancreas showing mild hyperplasia of the islet cells (blue arrow), normal acinar cell observed (blue arrow); CPAQ400: Pancrease showing an improved histopathological architecture and reorganized interlobular duct (blue arrow); CPME400: Pancreas of the CPME400-treated animal showing normal histopathology indicating ameliorative effects; CPAQ200+MET: Pancreas showing no defined pathological lesions in histoarchitecture of islets of Langerhans and acinar cells; CPME200+MET: Pancreas showing no defined pathological lesions in histoarchitecture of islets of Langerhans and acinar cells; CPAQ400+MET: Pancreas showing no pathological alteration of the β-cells of islets of Langerhans and normal appearance of acinar cells; CPME400+MET: Pancreas showing significant improvement in pancreatic morphological changes. ILD: Interlobular Duct; IL: Islet of Langarhans; AC: Acini cells; BV: Blood Vessels; CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin) Magnification × 40; Scale Bar = 10 μm.

Fig. 6

Histopathology of the liver. Normal: The liver of Normal group showing normal appearance of hepatocytes, portal space (PS), sinusoids (Black arrows) and Kupffer cells (K); Diabetic: Liver showing progressive worsening of sinusoidal enlargement (Black arrows) and liver fatty degeneration; MET: Liver of MET treated animals showing the onset of sinusoidal enlargement (Black arrows), small amount of fatty vacuoles (FV) were observed; CPAQ400: Normal histology of liver hepatocytes observed indicating ameliorative effect; CPME400: Normal histology of the liver hepatocytes was observed; CPAQ200+MET: Mild sinusoidal enlargement and few fatty acid vacuoles as a results of metformin presence; CPME200+MET: Mild sinusoidal enlargement and few fatty acid vacuoles; CPAQ400+MET: Showing normal histology of liver tissues but with a slight amount of fatty acid vacuole cells; CPME400+MET: showing normal histology of liver tissues but with a slight amount of fatty acid vacuole cells. CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin) Magnification × 40; Scale Bar = 10 μm.

Fig. 7

Histopathology of kidney. Normal: The kidney of Normal group showed no pathological changes appearance of the kidney, normal glomeruli, and tubules, Bowman's capsule (BC), glomerulus (G), proximal tubule (PT), distal convoluted tubular (DCT), Macula Densa cell (MD); Diabetic: kidney showing shrinkage of tubular and inflammation was observed; MET: Kidney showing mild shrinkage of tubules; CPAQ400 & CPME400: Kidney showing normal glomerulus, normal basement membrane, and capillaries, without any inflammatory cells; CPAQ200+MET & CPME200+MET: Kidney showing normal histology with mild shrinkage of tubules; CPAQ400+MET & CPME400+MET: Kidney showing normal histology of kidney tissues with mild shrinkage of tubular. CPME400 = Diabetic+400 mg/kg b.wt of methanolic C. pictus; CPAQ200+MET = Diabetic+(200 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME200+MET = Diabetic +(200 mg/kg b.wt of CPME+60 mg/kg b.wt metformin); CPAQ400+MET = Diabetic+(400 mg/kg b.wt of CPAQ+60 mg/kg b.wt metformin); CPME400+MET = Diabetic+(400 mg/kg b.wt of CPME+60 mg/kg b.wt metformin) Magnification × 40; Scale Bar = 10 μm.