Three Undescribed Iridoid Derivatives Isolated from the Fruits of Vitex trifolia with Their Cytotoxic and Antimicrobial Activities

Vitex trifolia L. is a medicinal plant and widely distributed in the northern mountainous areas of Vietnam. Phytochemical study on the fruits of this plant led to the isolation of nine iridoid derivatives (1-9) including three undescribed compounds (1-3). Their structures were elucidated to be 3 ''-hydroxyscrophuloside A(1) (1), 3 ''-hydroxycallicoside D (2), 2 '-p-hydroxybenzoylaucubin (3), 6 '-p-hydroxybenzoylmussaenosidic acid (4), nishindaside (5), agnuside (6), 10-O-vanilloylaucubin (7), 6 '-O-p-hydroxybenzoyl-gardoside (8), and buddlejoside B (9) based on extensive analyses of HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1, 2, 4, and 8 significantly posessed anti-barterial activity against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa strains with MIC values in range of 16-64 mu g/mL. At concentration of 20 mu M, compounds 1-9 did not show cytotoxic effects against human lung cancer cells (PC9).