New abietane diterpenoids from the mangrove Avicennia marina

Phytochemical investigations of the twigs of Avicennia marina yielded three new abietane diterpenoids 11-hydroxy-8,11,13-abietatriene 12-O-beta-xylopyranoside (1), and a pair of inseparable epimers 6H alpha-11,12,16-trihydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial 11,6-hemiacetal (2) and 6H beta-11,12,16-trihydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial 11,6-hemiacetal (3), as well as the new lignan (7'S*,8'R*)-4,4',9'-trihydroxy-3,3',5,5'-tetramethoxy-7,8-dehydro-9-al-2,7'-cyclolignan (5), together with 6,11,12,16-tetrahydroxy-5,8,11, 13-abitetetraen-7-one (4), lyoniresinol (6), lyoniresinol 9'-O-beta-D-glucopyranoside (7), and diacetylmartynoside (8). Structure elucidation of the new compounds was accomplished by analysis of their spectroscopic data. Compounds 2-4 showed moderate cytotoxic and antimicrobial activities.