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.

Regulation of Neuropeptide Y Receptor Gene Expression and ‎Hormone Level in Obese Male Rats Receiving 6-Gingerol and L-Arginine ‎Supplementation

“…However, NO overproduction in overweight and obese people has been attributed to augmented inducible nitric-oxide synthase (iNOS) activity in response to insulin and pro-inflammatory cytokines (9). The hypolipidemic effects of L-arginine and gingerol (35) reported in the present study agreed with previous studies for L-arginine (30,33) and gingerol. Previous studies have concluded that both factors can lower triglycerides, total cholesterol, and LDL in humans and rats.…”

“…Serum testosterone levels in the L-arginine and the 6-gingerol-treated group were significantly increased compared to the HC control group, similar to other studies (32)(33)(34). Increasing testosterone levels is a fundamental goal of researchers, not only because of its effect on enhancing lipolysis and its anti-obesity effects but also because of stimulating the fertility process (32,33). The present study, in agreement with a large group of studies, showed that oral administration of L-arginine and 6gingerol significantly augmented serum testosterone levels in the study group compared to the HC group.…”

“…Ghlissi et al suggested that dietary ginger for 30 days decreased blood glucose and oxidative stress factor, improved reproductive organ weights and testosterone levels, enhanced semen quantity and motility, and ameliorated antioxidant activities of male diabetic rats (31). Serum testosterone levels in the L-arginine and the 6-gingerol-treated group were significantly increased compared to the HC control group, similar to other studies (32)(33)(34). Increasing testosterone levels is a fundamental goal of researchers, not only because of its effect on enhancing lipolysis and its anti-obesity effects but also because of stimulating the fertility process (32,33).…”

Highbush Blueberry (Vaccinium corymbosum L.) Leaves Extract and Its Modified Arginine Preparation for the Management of Metabolic Syndrome—Chemical Analysis and Bioactivity in Rat Model

“…At the same time, increased fasting glucose (14.2 mmol/L) and insulin (3005 pg/mL) concentrations were observed in experimental animals from HFD group. This evidence of metabolic disorders indicates the development of experimental MS in animals, which also is verified by the elevated HOMA index [ 52 ]. Extract E1 administration in dose 150 mg/kg body weight caused a significant decrease in serum glucose (down to 11.4 mmol/L), while at doses of 250 mg/kg the effect was even more significant (down to 9.1 pg/mL).…”

Study of hepatoprotective effect of bearberry leaves extract under insulin resistance in rats

“…Current results are the part of the complex experiment; thus, the data proved the IR development have been already published [17]. Long-term administration of dex was accompanied by hyperglycemia and IR development.…”