New metabolic products of Aspergillus flavus. Part II. Asperflavin, anhydroasperflavin, and 5,7-dihydroxy-4-methylphthalide
Asperflavin, a yellow pigment from the culture filtrate of an entomogenous strain of Aspergillus flavus, is shown to be (+)-3,4-dihydro-3,6,9-trihydroxy-8-methoxy-3-methylanthracen-1 (2H)-one (I; R = H). New minor metabolic products isolated were anhydroasperflavin (1,6-dihydroxy-8-methoxy-3-methyl-9-anthrone)(III; R1= R3= H, R2= Me) and a lactone, shown to be 5,7-dihydroxy-4-methylphthalide (VIII; R1= R2= H). The yellow spore-heads contained a mixture of the known fungal pigments aspergin (XII; R = n-C5H11·CH:CH·) and flavoglaucin (XII; R = n-C7H15).