Antidiabetic Screening, Activity-guided Isolation and Molecular Docking Studies of Flower Extracts of Pongamia pinnata (L.) Pierre

Pongamia pinnata (L.) Pierre (Family: Fabaceae) is a famous traditional medicinal plant, the flowers of which are used for treating diabetes, however, the active constituent(s) is yet unidentified. Therefore, the present study aimed to carry out antidiabetic activity-guided isolation of extracts of flowers. Hexane extract being the most active (EC50, 900 µg/mL) was fractionated by partitioning and the most active hexane fraction (EC50, 570 µg/mL) was subjected to column chromatography which gave three isomers of compound 1 (4-Methoxy-7-phenyl-5H-furo [3,2-g][1] benzopyran-5-one), a furanoflavonoid. All the isomeric forms have equal antidiabetic activity (83.24%) with EC50 at 300 µg/mL.  The activity of the isolated compound was found to be higher as compared to standard drug acarbose (43.46%). Molecular docking studies of the compound indicated higher binding energy scores with antidiabetic targets as compared to the standard drug acarbose. The results of the present study indicate that the isolated compound may be developed into an antidiabetic drug.