A New 19(10→9)Abeo-Euphane Triterpenoid with other Terpenoid Components from Trichilia dregeana Leaves and their NO Production Inhibitory Activities in LPS-Stimulated RAW264.7 Macrophages.

Trichilia dregeana Sond. (Meliaceae) is a plant used in traditional medicine to treat wounds. The anti-inflammatory potential of the ethyl acetate leaf extract and the presence of euphane-type triterpenes in this extract have recently been reported by our group. Further investigation of the remaining subfractions of the ethyl acetate fraction afforded a new 19(10→9)abeo-euphane-type triterpenoid (1), along with six known terpenoids (2-7). The structure of the new compound was elucidated by analyses of the HR-ESI-MS, 1D and 2D NMR data and by comparison with previously reported data. We investigated the ability of the compounds to modulate the production of nitric oxide (NO) in LPS-stimulated RAW264.7 macrophages. The known compounds 3 and 6 exhibited moderate (IC50 72.06 µM) and mild (IC50 98.84 µM) inhibitory activities, respectively, without cytotoxic effects on the cells. These results, in conjunction with our previous findings, emphasize the significant role of terpenoid components in the anti-inflammatory efficacy of T. dregeana leaves and indicate that the rare 3,10-epoxy-19(10→9)abeo-euphane triterpenoids could serve as a chemotaxonomic marker for T. dregeana.

New 19(10 → 9)abeo-euphane-type triterpenoids from Trichilia dregeana leaves and NO production inhibitory activities.

Phytochemical investigation of the EtOAc soluble fraction from leaves of Trichilia dregeana Sond. (Meliaceae) afforded naturally rare four new pentacyclic triterpenoids (1-4), together with five known pentacyclic analogs (5-8, and 11) and two steroids (9 and 10). Their structures were elucidated by extensive spectroscopic techniques such as 1D and 2D NMR and HRESIMS data analyses. The absolute configuration of 1 was determined by using the single-crystal X-ray diffraction analysis. The nitric oxide (NO) production inhibitory assay indicated that the EtOAc fraction as well as 4 and 7 inhibited the NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with the IC50 values of 83.53 µg/mL and 81.31 and 85.71 µM, respectively. Compounds 1-4 are rare 19(10 â†’ 9)abeo-euphane-type triterpenoids bearing a 3,10-ether bridge. To the best of our knowledge, this study is the first isolation of triterpenoids with the 3,10-ether bridge in their skeleton from the genus Trichilia, providing new insights into the chemodiversity of the terpenoids in T. dregeana.