Effect of Propolis on Insulin Resistance in Fructose-drinking Rats

Abstract

Propolis, a honeybee product, contains a variety of biologically active substances. The present study was designed to investigate the eŠects of propolis on insulin resistance induced by fructose-drinking rats (FDR; type 2 diabetic animal model). Male Wistar rats (6 weeks old) received 15％ fructose solution in drinking water for 8 weeks. FDR showed signiˆcant increases in plasma levels of insulin, Homeostasis Model Assessment ratio (HOMA R, an index of insulin resistance), body weight, and systolic blood pressure but not blood glucose levels, when compared with control rats. Brazilian propolis extract (100 and 300 mg/kg, p.o.) treatment for 8 weeks signiˆcantly decreased the plasma level of insulin, HOMA-R, and body weight, increased plasma triglyceride levels without aŠecting blood glucose and total cholesterol levels, and tended to decrease systolic blood pressure. In isolated and perfused mesenteric vascular beds of FDR, propolis treatment resulted in a signiˆcant reduction of sympathetic nerve-mediated vasoconstrictor response to periarterial nerve stimulation (PNS; 8 Hz) and tended to increase the calcitonin gene-related peptide (CGRP) nervemediated vasodilator response to PNS, compared with those in untreated FDR. However, propolis treatment did not signiˆcantly aŠect norepinephrine-induced vasoconstriction and CGRP-induced vasodilation. These results suggest that propolis could be an eŠective functional food to prevent the development of insulin resistance.

Propolis Prevents Diet-Induced Hyperlipidemia and Mitigates Weight Gain in Diet-Induced Obesity in Mice

“…Recent study reported that propolis prevented the development of insulin resistance induced by fructose-drinking rats, 22) and that improvement of hyperglycemia and hypertension by propolis was ascribed to caffeoylquinic acid as one of the major bioactive constituents. 20,21) Therefore, it may be worthwhile to examine the hypolipidemic effect of caffeoylquinic acid in our experimental system.…”

“…17) Recent studies have reported that propolis prevented and mitigated diabetes and hypertension, [18][19][20][21][22] but it remains unclear whether propolis similarly prevents and mitigates the accumulation of visceral adipose tissues and hyperlipidemia. In this study we examined the effect of propolis on visceral fat and hyperlipidemia induced in a high-fat dietinduced obesity mouse model, and analyzed hepatic gene expression involved in lipid metabolism.…”

Propolis: Is there a potential for the development of new drugs?

“…Fuliang et al (2005) observed that the administration of water or ethanolic extract of propolis for 7 weeks to STZ-induced diabetic rats may control the glycemia and modulate glucose and lipid metabolism, leading to decreased outputs of lipid peroxidation and scavenging the free radicals in diabetic rats. Zamami et al (2007) reported that propolis treatment (100 and 300 mg/kg) of 15% fructose-treated rats for 8 weeks significantly decreased the plasma level of insulin and body weight, without affecting blood glucose levels. McLennan et al (2008) reported that propolis can accelerate wound healing and reepithelization of diabetic wounds in rodents, providing a rationale for studying topical application of this agent in a clinical setting.…”

Propolis and its direct and indirect hypoglycemic effect

“…[23] Propolis could be an effective functional food to prevent the development of insulin resistance induced by fructose-drinking rats in animal models that received 15% fructose solution in drinking water for 8 weeks. [24]…”