Officimalonic acids A−H, lanostane triterpenes from the fruiting bodies of Fomes officinalis

Phytochemical investigation of the methanolic extract of the fruiting bodies of Fomes officinalis led to the isolation of eight 24-methyl-lanostane triterpenes named officimalonic acids A−H, along with one known lanostane triterpene. Their structures were elucidated based on the analysis of spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism. Officimalonic acid A represents a previously unknown triterpene type with a 24-methyl-7(8 → 9)abeo-lanostane skeleton, and all of the compounds possessed a malonate half-ester moiety at C-3. Anti-inflammatory assay revealed that officimalonic acids D, E, G, H, and fomitopsin A showed potent inhibitory effects (IC50 = 5.1–8.9 μM) on nitric oxide production in lipopolysaccharide-induced RAW264.7 cells. Officimalonic acids E, G, H showed moderate cytotoxicity against H460, HepG2 and BGC-823 human cell lines. Eight 24-methyl-lanostane triterpenes, officimalonic acids A−H, were isolated and identified from the fruiting bodies of Fomes officinalis. Some of them showed potent inhibitory effects on NO production in LPS-induced RAW264.7 cells. [Display omitted] •Eight 24-methyl-lanostane triterpenes were isolated and identified from fruiting bodies of Fomes officinalis.•One of them has a 24-methyl-7(8 → 9)abeo-lanostane skeleton.•All of the compounds possessed a malonate half-ester moiety.•Some of the compounds showed potent inhibitory effects on NO production in LPS-induced RAW264.7 cells.