Abstract
Three new ergosterol derivatives, namely, fusaristerols B [(22E,24R)-3-palmitoyl-19(10 -> 6)-abeo-ergosta-5,7,9,22-tetraen-3 beta-ol] (1), C [(22E,24R)-ergosta-7,22-diene-3 beta,6 beta,9 alpha-triol] (3), and D [(22E,24R)-ergosta-7,22-diene-3 beta,5 alpha,6 beta,9 alpha-tetraol 6-acetate] (4), along with (22E,24R)-5 beta,8 beta-epidioxyergosta-22-en-3 beta-yl decanoate (2) and (22E,24R)-ergosta-7,22-dien-3 beta-ol (5), were isolated and characterized from the endophytic fungus Fusarium sp. isolated from Mentha longifolia L. (Labiatae) roots growing in Saudi Arabia. The structures of the isolated metabolites were verified based on UV, IR, NMR (1D and 2D), HRMS, and a comparison with the literature. All the metabolites were assessed for 5-lipoxygenase (5-LOX) inhibitory potential. Compounds 1 and 2 possessed 5-LOX inhibitory potential with an IC(50)s of 3.61 and 2.45 mu M, respectively, compared to that of indomethacin (IC50 1.17 mu M). In addition, their structure-activity relationship was discussed.