Abstract
Two new ergosterol derivatives namely, chlamydosterols A [(22E,24R)-ergosta-7,22-diene-3 beta,5 alpha,6 beta-triol 6-decanoate] (1) and B [5 alpha,6 beta,25-trihydroxy-(22E,24R)-ergosta-7,22-dien-3-one] (5) and three known ergosterols: ergosta-7,22-dien-3 beta-ol (2), ergosta-5,7,22-triene-3 beta-ol (3), and ergosta-7,22-diene-3 beta,5 alpha,6 beta-triol (4) were separated from the EtOAc extract of the endophytic fungus Fusarium chlamydosporum isolated from Anvillea garcinii (Asteraceae) leaves growing in Saudi Arabia. Their structural assignment was accomplished by various spectroscopic analyses, as well as comparing with the published data. The 5-lipoxygenase (5-LOX) inhibitory potential of the isolated metabolites was assessed. Compounds 1 and 3 displayed moderate 5-LOX inhibitory potential with IC(50)s 3.06 and 3.57 mu M, respectively compared to indomethacin (IC50 1.13 mu M).