Calotropis procera: UHPLC-QTOF-MS/MS based profiling of bioactives, antioxidant and anti-diabetic potential of leaf extracts and an insight into molecular docking

This work aims to investigate antioxidant/antidiabetic activities of aqueous and aqueous ethanol (20–80% ethanol:water, v/v) extracts from Calotropis procera leaves followed by profiling of related bioactives using UHPLC-QTOF-MS/MS technique. Of the extracts produced, 80% ethanolic extract offered highest level of total phenolics and total flavonoids with contribution 176.31 ± 2.09 mg GAE/g DE and 65.38 ± 2.65 mg RE/g DE, respectively. The α-Glucosidase and α-amylase inhibitory effect of 80% extract was found to be maximum with IC50 value of 0.78 ± 0.01 mg/mL and 0.93 ± 0.01 mg/mL, respectively among others. The same extract also showed higher total antioxidant power (184.91 ± 3.65 mg/g AAE) and antiradical effect with corresponding IC50 of 87.35 ± 2.45 µg/mL. UHPLC-QTOF-MS/MS investigation of 80% ethanolic extract led to identification/characterization of different antioxidant and antidiabetic metabolites such as p-hydroxybenzoic acid, 4-O-β-d-galactopyranosyl-d-fructose, myrciacitrin IV, quinic acid and astragaloside/kaempferol/quinic acid derivatives. Based on the present findings, 80% ethanol leaf extract of C. procera was found to be an important source of bioactives with significant potency of antioxidant, α-glucosidase and α-amylase enzyme inhibitory effects. Binding affinity data and interaction patterns, elucidated via docking simulations, of potential bioactives in C. procera leaf extract predicted that they can inhibit α-glucosidase and α-amylase synergistically to prevent hyperglycemia. These results explore potential uses of C. procera for development of functional foods and antioxidant/antidiabetic nutraceuticals.