Bombax ceiba calyx displays antihyperglycemic activity via improving insulin secretion and sensitivity: Identification of bioactive phytometabolomes by UPLC-QTof-MS/MS

Abstract

Vegetables are considered good food for the management of hyperglycemia. Bombax ceiba L. (family: Bombacaceae) calyces are part of traditional vegetables. This study evaluated its usefulness on various parameters responsible for the development of hyperglycemia and conducted phytometabolomic analysis to identify phytochemicals responsible for the observed activities. It was found that the aqueous methanol extract of its calyces (B. ceiba calyx extract, BCE) reduced (12.4%) significantly (p < 0.05) the development of sucrose-induced postprandial hyperglycemic load in rats. In-vitro studies revealed that BCE improved glucose-stimulated insulin secretory activity in MIN6 cells plausibly by decreasing ADP/ATP ratio. BCE also augmented concentration-dependent (5 µg, 10 µg, and 20 µg) increase in glucose uptake in hyperglycemic L6 myotubes both by non-insulin-dependent manner (35%, 68%, and 132%, respectively) and insulin-dependent manner (42%, 59%, and 172%, respectively). The insulin-stimulated GLUT4 translocation was compromised (34%) significantly (p < 0.05) under hyperglycemic condition; however, it was improved by 23% and 72% (p < 0.001) when L6 myotubes were primed with 10 and 20 µg of BCE, respectively. Hyperglycemia aggravated reactive oxygen species (ROS) generation in L6 myotubes. The ROS generation was significantly (p < 0.001) reduced by priming myotubes with BCE before challenging myotubes to hyperglycemic environment, possibly by preserving cellular antioxidant enzymes catalase, glutathione peroxidase, and reduced glutathione levels. Phytometabolomic analysis disclosed a number of phytochemicals present in B. ceiba calyces known to display these activities. This is the first study reporting antihyperglycemic activity in B. ceiba calyces, its mechanisms of action, and phytometabolomic profile applying UPLC-QTof-MS/MS technique. PRACTICAL APPLICATION: B. ceiba calyces are part of traditional vegetables. Our study finds that B. ceiba calyces contain phytochemicals possessing antihyperglycemic, insulin secretory, insulin sensitization properties, and potentials for preserving hyperglycemia-induced vitiations in cellular antioxidant defense. These observations provide foundation for exploring further possibilities of B. ceiba calyces to become valuable dietary inclusion in the diet of people suffering from metabolic disorders.

Keywords: Bombax ceiba calyces; GLUT4 translocation; hyperglycemia; insulin secretion; insulin sensitivity; oxidative stress; phytometabolic analysis.