A new labdane-type diterpenoid, named vitexnegundin (1), along with seven known compounds, including vitexilactone (2), vitetrifolin D (3), 13-hydroxy-5(10),14-halimadien-6-one (4), (rel 3S,5S,8R,9R,10S)-3,9-dihydroxy-13(14)-labden-16,15-olide (5), artemetin (6), vitexcarpin (7) and penduletin (8), were isolated from the leaves of Vitex negundo L. Their structures were elucidated by using spectroscopic methods, X-ray crystallographic analysis and comparison with those reported in the literature. Moreover, all isolated compounds 1-8 were evaluated for their antimicrobial activity against ESBL-producing Escherichia coli strain and methicillin-resistant Staphylococcus aureus.
Keywords: Vitex negundo L.; antimicrobial activity; labdane-type diterpenoid; vitexnegundin.