The chemical constituents from the stems and leaves of Mycetia hainanensis were isolated by silica gel, ODS gel, and Sephadex LH-20 gel column chromatography and preparative HPLC. The chemical structures of all the isolated compounds were identified on the basis of their physicochemical properties, spectroscopic data, as well as the comparison of their physicochemical and spectroscopic data with the reported data in literature. Twelve compounds were isolated from the 85% ethanol extract of the stems and leaves of M. hainanensis, and they were identified as mycehainanic acid(1), 11-methoxyviburtinal(2), isovaltrate acetoxyhydrin(3), jatamanvaltrate K(4), jatamanin C(5), sarmentol F(6), 4,5-dihydroblumenol A(7), petasitolone(8), xylaguaianol D(9), aristolan-9-en-1-one(10), 3α-hydroxycostic acid(11), and ilicic acid(12). Among them, compound 1 was a new nor-sesquiterpene, and compounds 2-12 were isolated from Mycetia for the first time. In addition, the MTS method was employed to assess the anti-rheumatoid arthritis activities of compounds 1-12 based on their anti-proliferative effects on synoviocytes in vitro. The results showed that compounds 1 and 6-12 exhibited notable anti-rheumatoid arthritis activities, showcasing inhibitory effects on the proliferation of MH7A synovial fibroblast cells with the IC_(50) ranging from(5.27±0.07) to(172.68±0.32)μmol·L~(-1), which were comparable to that of the positive control methotrexate \[IC_(50) of(132.39±0.21)μmol·L~(-1)\].
Keywords: Mycetia hainanensis; anti-rheumatoid arthritis activities; iridoids; nor-sesquiterpene; sesquiterpenes.