Two new compounds from leaves of Bruguiera cylindrica (L.) Blume with the in vitro α-glucosidase inhibitory activity

Introduction: Bruguiera cylindrica is one of the mangrove plants belonging to Bruguiera genus. This genus is characterized by the presence of a large number of compounds, but the research on bioactivities has not been investigated so far. In the present research, the α-glucosidase inhibitory activity, as well as chemical constituents of the ethyl acetate extract of this plant, were studied. Methods: The chemical structures of two new compounds were elucidated by spectroscopic and computational methods. Results: Two new compounds, benzobrugierol (1) and bruguierine (2), were isolated from leaves of Bruguiera cylindrica (L.) Blume, together with nine known ones, including lupeol (3), betulin (4), chrysoeriol (5), glut-5-ene-3-ol (6), cholesta-4-ene-3-one (7), 3α-(Z)-coumaroyllupeol (8), 3α-(E)-coumaroyllupeol (9), 3β-hydroxycholesta-5-ene-7-one (10) and β-sitosterol 3-O-β-D-glucopyranoside (11). Extracts and some isolated compounds were evaluated for α-glucosidase inhibitory activities. Conclusion: The results showed that most of the extracts and tested compounds exhibited activities better than the positive control acarbose, especially two new compounds 1 and 2 with their IC50 values of 17.9 ± 0.4 and 34.6 ± 0.7 (mg/mL), respectively.