Suresh R. Naik

An experimental evaluation of the antidiabetic and antilipidemic properties of a standardized Momordica charantia fruit extract.

BackgroundThe MCE, Momordica charantia fruit extract Linn. (Cucurbitaceae) have been documented to elicit hypoglycemic activity on various occasions. However, due to lack of standardization of these extracts, their efficacy remains questionable. The present study was undertaken by selecting a well standardised MCE. This study reports hypoglycemic and antilipidemic activities of MCE employing relevant animal models and in vitro methods.MethodsDiabetes was induced in Wistar rats by a s.c., subcutaneous injection of alloxan monohydrate (100 mg/kg) in acetate buffer (pH 4.5). MCE and glibenclamide were administered orally to alloxan diabetic rats at doses of 150 mg/kg, 300 mg/kg & 600 mg/kg, and 4 mg/kg respectively for 30 days, blood was withdrawn for glucose determination on 0, 7, 14, 21 and 30th days. On the 31st day, overnight fasted rats were sacrificed and blood was collected for various biochemical estimations including glycosylated haemoglobin, mean blood glucose, serum insulin, cholesterol, triglcerides, protein and glycogen content of liver. The hemidiaphragms and livers were also isolated, carefully excised and placed immediately in ice cooled perfusion solution and processed to study the glucose uptake/transfer processes. Hypolipidemic activity in old obese rats was evaluated by treating two groups with MCE (150 mg/kg & 300 mg/kg) orally for 30 days and determining total cholesterol, triglyceride and HDL-CH, LDL-CH and VLDL-CH levels from serum samples.ResultsSubchronic study of MCE in alloxan induced diabetic rats showed significant antihyperglycemic activity by lowering blood glucose and GHb%, percent glycosylated haemoglobin. Pattern of glucose tolerance curve was also altered significantly. MCE treatment enhanced uptake of glucose by hemidiaphragm and inhibited glycogenolysis in liver slices in vitro. A significant reduction in the serum cholesterol and glyceride levels of obese rats following MCE treatment was also observed.ConclusionOur experimental findings with respect to the mechanism of action of MCE in alloxan diabetic rats suggest that it enhances insulin secretion by the islets of Langerhans, reduces glycogenesis in liver tissue, enhances peripheral glucose utilisation and increases serum protein levels. Furthermore, MCE treatment restores the altered histological architecture of the islets of Langerhans. Hence, the biochemical, pharmacological and histopathological profiles of MCE clearly indicate its potential antidiabetic activity and other beneficial effects in amelioration of diabetes associated complications. Further, an evaluation of its antilipidemic activity in old obese rats demonstrated significant lowering of cholesterol and triglyceride levels while elevating HDL-cholesterol levels. Also, the extract lowered serum lipids in alloxan diabetic rats, suggesting its usefulness in controlling metabolic alterations associated with diabetes.

Cardioprotective activity of Ginkgo biloba Phytosomes in isoproterenol-induced myocardial necrosis in rats: A biochemical and histoarchitectural evaluation

The protective effects of Ginkgo biloba Phytosomes (GBP) in isoproterenol (ISO)-induced cardiotoxicity and the antioxidant activity involved in this protection were investigated in rats. Myocardial infarction was produced in rats with 65, 85, 120 and 200mg/kg of ISO administered subcutaneously (sc) twice at an interval of 24h. An ISO dose of 85mg/kg was selected for the present study as this dose offered significant alteration in biochemical parameters and moderate necrosis in heart. Effect of GBP oral treatment for 21 days at two doses (100mg and 200mg/kg body weight) was evaluated against ISO (85mg/kg, sc)-induced cardiac necrosis. Levels of marker enzymes (AST, LDH and CPK) were assessed in serum and heart, antioxidant parameters viz., reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) and malondialdehde (MDA) were assayed in heart homogenate. Significant myocardial necrosis, depletion of endogenous antioxidants and increase in serum levels of marker enzymes were observed in ISO-treated animals when compared with the normal animals. GBP elicited a significant cardioprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH, SOD, CAT, GPx and GR. The present findings have demonstrated that the cardioprotective effects of GBP in ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation of membrane.

Antioxidant and hepatoprotective effects of Ginkgo biloba phytosomes in carbon tetrachloride‐induced liver injury in rodents

Aim: The protective effects of Ginkgo biloba phytosomes (GBP) on carbon tetrachloride (CCl4)‐induced hepatotoxicity and the probable mechanism(s) involved in this protection were investigated in rats.

Hepatoprotective effect of Ginkgoselect Phytosome® in rifampicin induced liver injurym in rats: Evidence of antioxidant activity

The protective effects of Ginkgoselect Phytosome (GBP) on Rifampicin (RMP) induced hepatotoxicity and the probable mechanism(s) involved in this protection were investigated in rats. Liver damage was induced in Wistar rats by administering rifampicin (500 mg/kg, p.o.) daily for 30 days. Simultaneously, GBP at 25 mg/kg and 50 mg/kg, and the reference drug silymarin (100 mg/kg) were administered orally for 30 days/daily to RMP treated rats. Levels of marker enzymes (SGOT, SGPT and SALP), albaumin (Alb) and total proteins (TP) were assessed in serum. The effects of GBP on lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR) were assayed in liver homogenates to evaluate antioxidant activity. GBP (25 and 50 mg/kg) and silymarin elicited a significant hepatoprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH, SOD, CAT, GPX, GR, Alb and TP in a dose dependant manner. The present findings suggest that the hepatoprotective effect of GBP in RMP induced oxidative damage may be related to its antioxidant and free radical scavenging activity.

Polyamines: Potential anti-inflammatory agents and their possible mechanism of action

Objective: To evaluate the anti-inflammatory activity of exogenously administered polyamines on experimentally induced acute and chronic inflammation in wistar rats and to elucidate their possible mechanism of action. Materials and Methods: The in vivo anti-inflammatory activity of polyamines was studied using acute (carrageenin paw edema), sub-acute (cotton pellet granuloma) and chronic (Freunds adjuvant induced arthritis) models of inflammation. The biochemical parameters like liver lipid peroxides, SGOT and SGPT were also measured. Results: Polyamines exhibited significant anti-inflammatory activity in acute, sub-acute and chronic models of inflammation. Polyamines treatment inhibited the increase in lipid peroxides in liver and the serum concentration of marker enzymes (glutamate oxaloacetate transferase and glutamate pyruvate transferase) during inflammation. Conclusion: Polyamines possess anti-inflammatory activity in acute and chronic inflammation which can be attributed to their anti-oxidant and /or lysosomal stabilization properties.

Cardioprotective Activity of Polyherbal Extracts in Experimental Myocardial Necrosis in Rodents: An Evidence of Antioxidant Activity

The present study investigates the antioxidant activity of A.V. Circulo (AVC), a polyherbal formulation in isoproterenol(ISO)-induced oxidative stress in rats and attempts to correlate its cardioprotective activity with antioxidant activity. Myocardial necrosis was produced in rats with ISO (85 mg/kg, s.c.), injected twice at an interval of 24 h. AVC (500 mg/kg, p.o.) was administered to rats for 21 days and 45 days and its effect was evaluated on ISO-induced cardiac injury. The marker enzymes - AST, LDH & CPK were assayed in serum and heart, and antioxidant parameters, viz., reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) & glutathione reductase (GR), and malondialdehyde (MDA), were determined in heart homogenate. Significant myocardial necrosis, depletion of endogenous antioxidants and an increase in serum levels of marker enzymes were observed in ISO-treated rats when compared with normal rats. Daily pretreatment of AVC (500 mg/kg) for 21 & 45 days to rats which were treated with ISO on the last 2 days, resulted in a significant cardioprotective and antioxidant activity, reflected by decreased levels of serum marker enzymes & MDA, and restored activities of marker enzymes, GSH, and antioxidant enzymes in the heart. AVC (500 mg/kg) administration for 45 days showed greater cardiac protection than for 21 days. It is concluded that AVC (500 mg/kg) oral treatment for 21 & 45 days to ISO-challenged rats augments endogenous antioxidant enzymes in the rat heart and prevents lipid peroxidation of the membrane, thereby salvaging the myocardium from the deleterious effects of ISO.

Hypolipidemic Activity Evaluation of DRF/AY/4013, an Herbal Formulation in Experimentally Induced Hyperlipidemic Rats

The present study was designed to evaluate the efficacy of an herbal product DRF/AY/4013 for its hypolipidemic activity in various experimental rat models. An indigenous polyherbal formulation DRF/AY/4013, composed of different phytoconstituents like Terminalia arjuna, Commiphora mukul, Allium sativum, Cyperus rotundus and Acorus calamus extracts, exhibited potential hypolipidemic activity treatment in triton induced hyperlipidemic rats. Further, it also showed promising hypolipidemic activity in both high fat diet (HFD) induced hyperlipidemic rats and propylthiouracil (PTU) induced hyperlipidemic rats. In all the experimental hyperlipidemic models, DRF/AY/4013 treatment demonstrated dose dependent hypolipidemic activity at 200, 400 and 800 mg/kg dose levels by decreasing serum lipid and lipoprotein profile, atherogenic index (AI) and lipid peroxidation process. Furthermore the 800 mg/kg dose level group V rats exhibited pronounced hypolipidemic activity almost comparable to atorvastatin standard drug (10 mg/kg) treated group VI rats. In HFD induced hyperlipidemic rat model, DRF/AY/4013 treated groups III, IV, V exhibited mild, minimal and negligible degree of cytoplasmic fatty infiltration respectively in hepatocytes as compared to marked degree in untreated control HFD induced group II rats. In short, the DRF/AY/4013 treatment demonstrated a promising hypolipidemic activity in all experimental rat models and therefore, needs further clinical evaluation in humans.