Chromenes of polyketide origin from Peperomia villipetiola

The extracts of leaves and stems of Peperomia villipetiola have been found to contain myristicin and seven chromenes ( 1– 7) of orsellinic acid-type. The anti-fungal activities of the chromenes measured by bioautography against Cladosporium cladosporioides and Cladosporium sphaerospermum indicated compounds 6 and 7 as the most active. An extract of leaves and stems of Peperomia villipetiola has been found to contain myristicin (3-methoxy-4,5-methylenedioxy-allylbenzene) and seven chromenes, whose structures are methyl 5-hydroxy-7-methyl-2,2-dimethyl-2 H-1-chromene-6-carboxylate ( 1), methyl 5-methoxy-7-methyl-2,2-dimethyl-2 H-1-chromene-8-carboxylate ( 2), methyl 7-hydroxy-5-methyl-2,2-dimethyl-2 H-1-chromene-6-carboxylate ( 3), methyl 7-methoxy-5-methyl-2,2-dimethyl-2 H-1-chromene-6-carboxylate ( 4), 5-methanol-7-hydroxy-2,2-dimethyl-2 H-1-chromene-6-carboxylic acid ( 5), 5-methanol-7-methoxy-2,2-dimethyl-2 H-1-chromene-6-carboxylic acid ( 6), and methyl 5-acetoxymethanol-7-hydroxy-2,2-dimethyl-2 H-1-chromene-6-carboxylate ( 7). A biosynthetic rationale for 1– 7 suggests that orsellinic acid may be a common intermediate. The anti-fungal activities of the chromenes were measured bioautographically against Cladosporium cladosporioides and Cladosporium sphaerospermum: compounds 6 and 7 were found to be the most active.