A plant-derived fungus, Penicillium janthinellum, obtained from Melia azedarach, produced ergosterol and ergosterol 5alpha,8alpha-peroxide along with a mixture of rare C25 steroid epimers. The C25 steroids, named neocyclocitrinols, shows exactly the same tetracyclic ring system present in cyclocitrinol, which was isolated from a sponge-derived Penicillium citrinum, with the same bicyclo [4:4:1] skeleton at A/B rings, but showing different side chains. The P. janthinellum was cultivated over white corn and the three steroids were isolated by several silica gel based chromatographic procedures and identified by extensive NMR methods, mainly ¹H - 13C correlations and ¹H - ¹H COSY and TOCSY. The biosynthetic origin of the cyclocitrinols is also discussed.
endophytic fungi; Melia azedarach; Penicillium janthinellum; neocyclocitrinols
