Five triterpenoids from the stems of Lasianthus bidoupensis V.S. Dang & Naiki (Rubiaceae)

Abstract

Lasianthus bidoupensis, belonging to Rubiaceae, has been recently found and has not been studied on chemical constituents and biological activities whereas species of the same genus have been used in traditional medicine and possessed diverse bioactivities. This paper reported the isolation and structural elucidation of organic compounds from the n-hexane extract of L. bidoupensis stems in order to give more chemical and biological information on this species. From the dried powder of L. bidoupensis stems, the crude extract was obtained by maceration of material in ethanol. This extract was separated into different polar ones by the method of liquid‒liquid extraction. The n-hexane extract, exhibited the strongest cytotoxic activity against MCF-7 cell line, was thus chosen to isolate the organic compounds by silica gel column chromatography. Five compounds were isolated as lupeol (1), 3-epi-betulinic acid (2), 3-epi-3-O-acetyl betulinic acid (3), 3-epi-oleanolic acid (4), and vergatic acid (5). The chemical structures of the isolated compounds were elucidated based on MS and NMR spectral data as well as a comparison of their NMR data with the published ones. Among them, compounds 2‒5 were reported in the genus Lasianthus for the first time and compound 3 showed the strongest MCF-7 cytotoxic activity with IC50 of 13.88±0.11 mg/mL.