HYPOGLYCEMIC AND HYPOLIPIDEMIC ACTIVITY OF ARGININE CONTAINING BEARBERRY LEAVES EXTRACT IN INSULIN RESISTANT RATS

Abstract

Introduction. In recent decades, diabetes mellitus type 2 (DM2) has become one of the leading causes of deaths worldwide. A number of studies confirmed the causal relationship between the development of insulin resistance (IR) and DM2. At the same time, traditionally and for many years the plants or substances isolated from them have been using in the DM2 treatment and correction of its complications.

The aim of the study – to find out the effect of ethanolic polyphenol Bearberry leaves (Arctostaphylos uva-ursi) extract enriched with arginine (PE50_arg) on tolerance to glucose and lipid metabolism under experimental IR in rats.

Research Methods. Adult male outbred albino rats were used in the present study. Two experimental IR models were conducted: daily intraperitoneal administration of dexamethasone and a diet enriched with fructose. Treating was performed by oral administration of polyphenolic alcohol extract (PE50) and the corresponding extract with the addition of arginine (PE50_arg). IR was confirmed by measuring immunoreactive insulin (IRI) and plasma glucose levels. At the end of the experiment, the lipid profile was investigated in the obtained serum samples. The statistical processing of the data was carried out using the STATISTICA program (StatSoftInc., USA, version 6.0).

Results and Discussion. A diet for 7 weeks enriched with fructose caused IR in rats. Also we observed increased triacylglycerol (TAG), free fatty acids (FFA) and cholesterol (Ch) levels. Daily injections of dexamethasone, which maintained the hormone level for 5 weeks, led to the IR development. Under hormone-induced IR also FFA and TAG levels were elevated, but Ch concentration in blood plasma did not significantly change. Both extracts, PE50 and PE50_arg, improve cell sensitivity to insulin in experimental IR models. At the same time, PE50_arg has a more pronounced normalizing effect on the lipid parameters being investigated.

Conclusions. Our results suggest that PE50_arg may be a potentially promising anti-diabetic agent.