Steroids and an oxylipin from an algicolous isolate of Aspergillus flavus.

A new oxylipin, (8E,12Z)-10,11-dihydroxyoctadeca-8,12-dienoic acid (1), a new steroid, 3β,4α-dihydroxy-26-methoxyergosta-7,24(28)-dien-6-one (2), and four known steroids, episterol (3), (22E,24R)-ergosta-7,22-dien-3β,5α,6α-triol (4), (22E,24R)-ergosta-5,22-dien-3β-ol (5), and (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (6), were isolated from the cultures of Aspergillus flavus, an endophytic fungus isolated from the marine red alga Corallina officinalis. Their structures and relative stereochemistry were elucidated by 1D, 2D NMR and mass spectroscopic techniques. 1 and 2 exhibited low activity to inhibit acetylcholinesterase and no activity against plant pathogenic fungi Colletotrichum lagenarium and Fusarium oxysporum.