Cucurbita ficifolia Bouché fruit acts as an insulin secretagogue in RINm5F cells

Diabetes mellitus (DM) is an important global public health problem. Despite the availability of drug therapy, patients have continued using plants with anti-diabetic properties as alternative treatments for diabetes. Cucurbita ficifolia Bouché (C. ficifolia) is a plant cultivated in Mexico for its edible fruit that is medicinally used to control type 2 DM (T2D). The hypoglycemic effect of C. ficifolia has been demonstrated in different experimental models and in T2D patients. However, no studies have determined the mechanism of action of this hypoglycemic effect. The aim of the present investigation was to determine if the hypoglycemic action of C. ficifolia and D-chiro-Inositol (DCI; a compound found in the fruit of C. ficifolia) occurs through an increase in the production of insulin. An aqueous extract of this fruit was obtained and standardized by its content of DCI, the principal hypoglycemic compound of the fruit. To study the mechanism of hypoglycemic activity of this extract and DCI alone, RINmF5 cells were exposed to different concentrations of both the extract and DCI, and the production of insulin and Kir6.2 channels were measured. The mRNA expression levels of insulin and Kir6.2 were found to be increased in cells that were treated with DCI and the C. ficifolia aqueous extract. This effect suggests a mechanism of action that involves both the expression and secretion of insulin. This research maintains the interest in developing new nutraceutics from C. ficifolia fruits for use in the treatment of T2D. Cucurbita ficifolia Bouché fruit acts as an insulin secretagogue in RINm5F cells