Laxilignans A-C from the leaves of Terminalia laxiflora Engl. and their α-glucosidase inhibitory activity

Three previously undescribed dibenzylbutane lignans, laxilignans A−C, together with fifteen known compounds were isolated and characterized from the leaves of Terminalia laxiflora Engl. The structures of laxilignans A−C were elucidated by extensive 1D and 2D NMR analyses, together with mass spectrometry. The inhibitory activity of the isolated compounds against α-glucosidase enzyme, obtained from Saccharomyces cerevisiae, was evaluated in comparison to acarbose (IC50 = 16.42 ± 0.14 µM). The results revealed that corilagin, chebulagic acid, laxilignan A, termilignan B, termitomenin C, arjunglucoside II, and laxilignan B possess α-glucosidase inhibitory potential, with IC50 values in the range of 1.61 ± 0.05 – 403.5 ± 29.5 μM, respectively. The results of the molecular docking revealed that the two laxilignans A and B showed comparable binding affinities to those of acarbose with the binding sites of the human α-glucosidase enzyme. These findings suggest that dibenzylbutane lignans may act as promising lead compounds for the development of α-glucosidase inhibitors.