Terpenoids from Phaulopsis imbricata (Acanthaceae)

Abstract

The whole plant of Phaulopsis imbricata (Forssk.) Sweet (Acanthaceae) was collected at Bansoa, Cameroon, shade dried and extracted by maceration in methanol. This study was carried out to isolate secondary metabolites from this plant species that has not been investigated so far. Two lupane-type triterpenoids, one β-type carotenoid, one eudesmane-type sesquiterpenoid, and one sterol glycoside were isolated from the dried methanol extract using solvent partitioning, column chromatography and re-crystallization. They were identified as lupeol, betulin, (all-E)-lutein, cryptomeridiol, and sitosterol 3-O-β-D-glucopyranoside, respectively. The structures of the isolated compounds were elucidated on the basis of spectroscopic methods including 1D-and 2D-nuclear magnetic resonance (NMR), infrared (IR) and mass spectrometry (MS). This is the first report of these compounds from the genus Phaulopsis. To the best of our knowledge, P. imbricata is also the first species of the genus to be phytochemically studied.