A new dihydroagarofuranoid sesquiterpene from Microtropis fokienensis with antituberculosis activity

Abstract

A new dihydroagarofuran-based sesquiterpene, 8-acetoxymutangin (1), was isolated from the stems of Microtropis fokienensis, together with eight known compounds, including mutangin (2). Their structures were determined through in-depth spectroscopic and mass-spectrometric analyses. Among the isolated compounds, 1 exhibited potent in vitro antituberculosis activity, with an MIC value of 10.0 μg/ml against Mycobacterium tuberculosis 90-221387, which is considerably better than that of mutangin (2). The activity of 1 lies in the same range as that of the clinic drug ethambutol (MIC 6.25 μg/ml), despite completely different chemical structures, which indicates different modes of action. © 2007 Verlag Helvetica Chimica Acta AG, Zürich.