Two new cadinane sesquiterpenes and one new lignan from Abelmoschus moschatus subsp. tuberosus and their α-glucosidase inhibitory activity.

• Three new compounds were isolated from Abelmoschus moschatus subsp. tuberosus. • The structures were successfully determined by spectroscopic evidence. • Hibiscone B inhibited α -glucosidase enzyme with IC 50 of 121.7 ± 3.9 μg/mL. • N - trans -feruloyl tyramine inhibited α -glucosidase enzyme with IC 50 of 4.3 ± 0.5 μg/mL. Two new cadinane sesquiterpenes, cadinoschanes A and B (1 and 2), one new norlignan, lignanoschane A (6) along with seven known compounds, hibiscone B (3), 7 β - O - β -glucopyranosyl bombaxone (4), 2,7 β ,8 β -trihydroxy trans -calamenene 7-O- β -D-glucopyranoside (5), clemastanin A (7), (−)-3,4,3′,4′-tetrahydroxy-9,7′ β -epoxylignano-7 β ,9′-lactone (8), N - trans -feruloyl tyramine (9), and methyl (3 R)-3-[(3 R)-3-{(3 R)-3-hydroxybutanoyloxy} butanoyloxy} butanoate (10) were isolated from Abelmoschus moschatus subsp. tuberosus (Span.) Borss. Waalk. Their structures were determined on the basis of extensive spectroscopic methods, including 1D, 2D NMR and MS data and comparing experimental CD with theoretical CD calculations. Compounds 3 and 9 showed significant α -glucosidase inhibitory activity with IC 50 values of 121.7 ± 3.9 and 4.3 ± 0.5 μg/mL, respectively, compared to those of a positive control, acarbose with IC 50 value of 183.5 ± 12.2 μg/mL. [ABSTRACT FROM AUTHOR]