Anti-Inflammatory triterpenoids from the stems of microtropis fokienensis

Three new ursane- and four new oleanane- type triterpenoids 1-7 were isolated, along with six known compounds 8-13, from the methanolic extract of Microtropis fokienensis. All structures were elucidated by mass and NMR spectroscopic methods. The isolates 4-10 and known compounds 14-17 that were previously isolated from this material were evaluated for anti-inflammatory activity based on effects against superoxide anion generation and elastase release by neutrophils in response to fMLP/CB. 11a,30- Dihydroxy-2,3-seco-olean- 12-en-2,3-dioic anhydride (7) was the first triterpene anhydride from the genus of Microtropis to have the ring A expanded to a seven-membered ring; it showed significant anti-inflammatory activity against superoxide anion generation and elastase release. Unexpectedly, 30-hydroxy-2,3-seco-lup-20(29)-ene-2,3-dioic acid (17) showed the best effect against superoxide anion generation and elastase release with IC50 values of 0.06 ± 0.01 and 1.03 ± 0.35 μg/mL, respectively. Compound 17 had a dioic acid function, and compound 7 had an anhydride function modification in ring A; both showed promising activity in the target assays. copy;2014 by the authors; licensee MDPI, Basel, Switzerland.