Influence of piperine and quercetin on antidiabetic potential of curcumin

BACKGROUND

Curcumin is a nutraceutical obtained from the rhizomes of Curcuma longa with a significant medicinal value against numerous disorders. However, the potential cannot be completely exploited due to low in vivo bioavailability. Hence, in order to enhance the bioavailability of curcumin, we combined it with the bioavailability enhancers like piperine and quercetin.

METHODS

The present study was targeted to explore the antidiabetic potential of combinatorial extract of curcumin with piperine and quercetin (CPQ) in streptozotocin- and nicotinamide-induced diabetic rats. Diabetes mellitus was induced by single intraperitoneal injection of streptozotocin (55 mg/kg) and nicotinamide (120 mg/kg-1). CPQ was orally administered at 100 mg kg-1 dose/day for a period of 28 days. At the end of 28 days, blood was analyzed for glucose, high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol level. Oral glucose tolerance test (OGTT) was also conducted at the end of 28 days.

RESULTS

Oral administration of CPQ at the dose of 100 mg kg-1 significantly (p<0.01) reduced plasma glucose at the end of 28 days, as compared to the diabetic control group. The reduction in the plasma glucose produced by the CPQ extract was equivalent to that of glibenclamide and significantly more compared to curcumin alone (p<0.01). Furthermore, a significant (p<0.01) reduction in the raised LDL, cholesterol and triglycerides and improvement was observed in the group fed with CPQ compared to diabetic control as well as the alone (p<0.05) curcumin group. There was a significant improvement in the body weight with CPQ compared to diabetes control group. OGTT revealed a significantly high glucose tolerance in CPQ fed rats compared to the diabetic control as well as the rats fed with curcumin alone.

CONCLUSIONS

Treatment with combinatorial extract of curcumin presented a significantly better therapeutic potential when compared with curcumin alone, which reveals that CPQ, with reduced dose of curcumin may serve as a therapeutic agent in the treatment of type 2 diabetes mellitus.

Synergistic combinatorial antihyperlipidemic study of selected natural antioxidants; modulatory effects on lipid profile and endogenous antioxidants

Background

Hyperlipidemia, a major pathological condition associated with disrupted lipid levels and physiological redox homeostasis. The excessive release of reactive oxygen species (ROS) leads to enhanced lipid peroxidation, aggravated atherosclerosis and oxidative stress. Integration of natural antioxidant blends in alone or with conventional treatments can alleviate these issues synergistically contributing least side effects. Published literature reported the efficacy of natural antioxidants as individual and in combinations in various conditions but less data is available on their evaluation in low dose ratio blends particularly in hypercholesterolemic diet.

Methods

Antihyperlipidemic effects of selected natural antioxidants; the phenolic oligomeric proanthocyanidins (OPC) and pterostilbene (PT) with niacin (NA) were investigated in current study. Their effects on lipid profile, lipid peroxidation and their aptitude to establish redox state between oxidants and antioxidants in body were evaluated in high cholesterol diet fed animal model. Male albino rabbits (n = 6) weighing 1.2–1.6 kg, supplemented with high cholesterol diet (400 mg/kg) for 12 weeks were used in the experiment. Antioxidants were administered individual high (100 mg/kg) and in low dose combinations (total dose = 100 mg/kg). Student’s t test and one way analysis of variance (ANOVA) followed by Dunnet’s test were used as statistical tools for evaluation.

Results

The results showed synergistic effects of low dose antioxidant blends. Therapies retarded elevation in blood lipid levels, lipid peroxidation and blood antioxidant depletion and consequently contributed in reestablishing redox homeostasis. The LDL/HDL ratio and atherogenic index were suppressed significantly in blend therapies with maximum effects of 59.3 and 25 % (p >0.001) observed in 50:30:20 ratios of OPC, NA and PT, compared to individual therapies 37 and 18 % max respectively. Moreover the results were also in close proximity with the statin therapy (52.66, 26.28 %).

Conclusion

This study provides an evidence for natural antioxidants blends superiority over individual therapy in chronic diseases like hyperlipidemia. Such therapies in human equivalent doses can help in mitigating chronic illnesses in general populations.

Blood glucose level and lipid profile of alloxan-induced hyperglycemic rats treated with single and combinatorial herbal formulations

The current study sought to investigate the capacities of single and combinatorial herbal formulations of leaf extracts of Acanthus montanus, Asystasia gangetica, Emilia coccinea, and Hibiscus rosasinensis to reverse hyperglycemia and dyslipidemia in alloxan-induced diabetic male rats. Phytochemical composition of the herbal extracts, fasting plasma glucose concentration (FPGC), and serum lipid profile (SLP) of the rats were measured by standard methods. The relative abundance of phytochemicals in the four experimental leaf extracts was in the following order: flavonoids > alkaloids > saponins > tannins. Hyperglycemic rats (HyGR) treated with single and combinatorial herbal formulations showed evidence of reduced FPGC compared with the untreated HyGR and were normoglycemic (FPGC < 110.0 mg/dL). Similarly, HyGR treated with single and combinatorial herbal formulations showed evidence of readjustments in their SLPs. Generally, HyGR treated with triple herbal formulations (THfs) exhibited the highest atherogenic index compared with HyGR treated with single herbal formulations (SHfs), double herbal formulations (DHfs), and quadruple herbal formulation (QHf). The display of synergy or antagonism by the composite herbal extracts in ameliorating hyperglycemia and dyslipidemia depended on the type and number of individual herbal extract used in constituting the experimental herbal formulations. Furthermore, the capacities of the herbal formulations (SHfs, DHfs, THfs, and QHf) to exert glycemic control and reverse dyslipidemia did not follow predictable patterns in the animal models.