Antioxidant and Anti-Inflammatory Effects of a Hypoglycemic Fraction from Cucurbita ficifolia Bouche in Streptozotocin-Induced Diabetes Mice

Type 2 diabetes is characterized by oxidative stress and a chronic low-grade inflammatory state, which also play roles in the pathogenesis of this disease and the accompanying vascular complications by increasing the production of free radicals and pro-inflammatory cytokines. Cucurbita ficifolia Bouche (C. ficifolia) is an edible Mexican plant whose hypoglycemic activity has been demonstrated in several experimental and clinical conditions. Recently, D-chiro-inositol has been proposed as the compound responsible for the hypoglycemic effects; however, the antioxidant and anti-inflammatory potential of this plant has not yet been explored. The aim of this research is to study the influence of a hypoglycemic, D-chiro-inositol-containing fraction from the C. ficifolia fruit (AP-Fraction) on biomarkers of oxidative stress, as well as on the inflammatory cytokines in streptozotocin-induced diabetes. The AP-Fraction obtained from the mature fruit of C. ficifolia contained 3.31 mg of D-chiro-inositol/g of AP-Fraction. The AP-Fraction was administrated daily by gavage to normal mice for 15 days as a preventive treatment. Then these animals were given streptozotocin, and the treatments were continued for an additional 33 days. Pioglitazone was used as a hypoglycemic drug for comparison. Administration of the AP-Fraction significantly increased glutathione (GSH) and decreased malondialdehyde (MDA) in the liver without significantly affecting the levels in other tissues. The AP-Fraction reduced TNF-alpha and increased IL-6 and IFN-gamma in serum. Interestingly, the AP-Fraction also increased IL-10, an anti-inflammatory cytokine. These results suggest that C. ficifolia might be used as an alternative medication for the control of diabetes mellitus and that it has antioxidant and anti-inflammatory properties in addition to its hypoglycemic activity.