Antidiabetic Potential of Abelmoschus manihot Flower Extract: In Vitro and Intracellular Studies

Abelmoschus manihot (L.) Medic flower (AMf) exhibits both nutritional value and bioactivities such as antioxidative, anti-inflammatory, neuroprotective, cardioprotective, and hepatoprotective effects. The aim of this investigation was to examine the potential impact of three different solvent extracts of AMf: supercritical CO2 extraction extract, water extract, and ethanol extract (AME), on management of diabetes. All three extracts demonstrated significant inhibitory effects on alpha-glucosidase (IC50 = 157-261 mu g/mL) and lipase (IC50 = 401-577 mu g/mL) activities while enhancing the alpha-amylase activity (32.4-41.8 folds at 200 mu g/mL). Moreover, all three extracts exhibited notable inhibition of the formation of advanced glycation end-products, including the Amadori products (inhibition rates = 15.7-36.6%) and the dicarbonyl compounds (inhibition rates = 18.6-28.3%). Among the three extracts, AME exhibited the most pronounced inhibitory effect. AME displayed substantial in vitro and intracellular antioxidative activity, and effectively reduced ROS production (135% at 500 mu g/mL) in beta-cells under hyperglycemic (HG) conditions. AME also enhanced the activity and gene expression of antioxidant enzymes, which were markedly decreased in the HG-induced beta-cells. Furthermore, AME protected beta-cell viability and maintained normal insulin secretion under HG conditions, likely due to its ability to reduce oxidative stress within beta-cells. This study demonstrated the potential of AME in preventing and managing diabetes and its associated complications. Further in vivo research is necessary to thoroughly elucidate the preventive effects and their underlying mechanisms.