Synergistic effect of quercetin and 6-gingerol treatment in streptozotocin induced type 2 diabetic rats and poloxamer P-407 induced hyperlipidemia

Abstract

Ginger and quercetin have been reported to have significant antidiabetic effects. It has been proposed that 6-gingerol and quercetin are responsible for the antidiabetic activity and that a combination of the two produces a synergistic effect. However, the per se effect of 6-gingerol has not been reported. The objective of this study was to investigate the effects of 6-gingerol and quercetin per se, on streptozotocin induced non-insulin dependent diabetes mellitus (NIDDM) and hyperlipidemia. 6-Gingerol and quercetin reduced fasting glucose significantly with producing significant changes in the insulin levels of diabetic rats. The amelioration was significantly more with the combination, compared with either compound alone. The results of the oral glucose tolerance test (OGTT) indicated that 6-gingerol and quercetin reduced streptozotocin (STZ) induced increases in both area under curve glucose (AUC_glucose) and area under curve insulin (AUC_insulin) in high fat feed type 2 diabetic rats. Treatment with 6-gingerol and quercetin reduced the levels of lipids in rats with NIDDM significantly. 6-Gingerol and quercetin had antihyperlipidemic effects in polaxamer P-407-induced hyperlipidemia. Quercetin and 6-gingerol show reduced serotonin induced hyperglycemia. This is the first study to demonstrate synergism of 6-gingerol and quercetin that has significant antidiabetic and beneficial cardiac effects in type 2 diabetic rats and polaxamer-induced hyperlipidemic rats. The synergistic action is probably through modulation of the serotonergic system.