Effect of different solvents on bioactive phenolics and antioxidant, antimicrobial, and α-glucosidase inhibition activities of Barringtonia acutangula Gaertn. flower extracts.

Barringtonia acutangula Gaertn. is a well-known vegetable and medicinal plant. This study assessed solvents' effect on phytochemical contents and bioactivities of flower extracts. High-polar extracts (ethanol, aqueous) demonstrated much higher phenolic contents (132.21, 240.83 mg gallic acid equivalent per gram of extract, respectively) than non-/medium-polar extracts, with more impressive flavonoid/saponin contents. Aqueous extract was highlighted for antioxidant activity and α-glucosidase inhibition (IC50 = 35.01, 5.63 μg/mL, respectively) on which HPLC analysis revealed gallic acid (1), pyrogallol (2), ilexsaponin A1 (3) as major compounds for 1.83, 1.26, 0.15%, respectively. Phenolics 1 and 2 displayed strong α-glucosidase inhibition (IC50 6.6 - 18.7 μM), consolidated by molecular docking studies and molecular dynamics simulations, based on their stable complexes with α-glucosidase protein (MAL32) via H-bonds of hydroxy phenol moieties, which was more effective in 2. The study suggested the potency of B. acutangula flower water extract and its phenolics, displaying the need for in-depth investigation.