Antibacterial phloroglucinols derivatives from the leaves of Mallotus oppositifolius (Geisler) Mull. Arg. (Euphorbiaceae)

From the ethno-medicinally used leaves of Mallotus oppositifolius, four acylphloroglucinol derivatives, namely Acronyculatin SeU (1-3) and Mallotojaponin D (4) were isolated along with seven known compounds (5-11). Structures were elucidated by comprehensive spectroscopic analyses and HRMS data. Absolute configurations were assigned by careful comparison of their specific optical rotation with those of closely related compounds. Compounds 1, 2, 6 and 11 demonstrated inhibitory activity against the bacterial strains E. coli, S. aureus, S. typhi, P. aeruginosa with minimum inhibitory concentration (MIC) values ranging from 3.125 to 50 mu g/ml.