Triterpene Acids from Mesona procumbens Exert Anti-inflammatory Effects on LPS-Stimulated Murine Macrophages by Regulating the MAPK Signaling Pathway

Five new triterpene acids, mesonaic acids A-C (1-3), 2 alpha,3 alpha,19 alpha-trihydroxy-24-nor-4(23),12-oleanadien-28-oic acid (4), and 3 alpha,19 alpha,22 alpha-trihydroxy-2-oxo-12-ursen-28-oic acid (5), and 10 known triterpene acid compounds (6-15) were isolated from a methanolic extract of Mesona procumbens. Triterpenes 1-3 possess unusual hexacyclic skeletons with a 13 alpha,27-cyclopropane ring. Regarding their anti-inflammatory activity, compounds 1-3, 6, and 7 inhibited NO production with EC50 values lower than 15 mu M, which were better than that of the positive control quercetin. Compounds 1-3, 6, and 7 markedly decreased levels of the inducible iNOS and COX-2 proteins in macrophages by inhibiting the activation of NF-kappa B through interference with the MAPK signaling pathway. Based on these data, compounds 1-3, 6, and 7 have great potential as NO inhibitors.

Automated summary

Five new triterpene acids were isolated from a methanolic extract of Mesona procumbens, showing potential as NO inhibitors. These compounds also demonstrated the ability to inhibit NF-κB activation by interfering with the MAPK signaling pathway, leading to decreased levels of inflammatory proteins.