Abstract
Five new 3-O-alkyl-4a,10a-dihydrofusarubins (2–6) were isolated from the culture filtrate of a strain of Fusarium sp. (Mj-2), together with the known metabolite, anhydrofusarubin (1). The structures of the new metabolites were elucidated by spectroscopic analyses to be 3-O-butyl, 3-O-3′-methylbutyl, 3-O-2′-methylbutyl and 3-O-2′-phenylethyl-4a,10a-dihydrofusarubin A, and an isomer of 3-O-2′-phenylethyl-4a,10a-dihydrofusarubin A. Their antifungal and antibacterial activities were evaluated together with a 3-O-methyl derivative (7) prepared from 3-O-butyl-4a,10a-dihydrofusarubin A (2), indicating that the size of the O-substituent at C-3 in the 4a,10a-dihydrofusarubins negatively affected the metabolites' antimicrobial activity.
