Cultures of Alternaria chrysanthemi normally produce radicinin (1) and radicinol (2) when cultured on Czapek-Dox medium or on potato dextrose broth. We have observed that long-term cultures of A. chrysanthemi grown on malt-extract broth produce 3-epiradicinol (3), the novel metabolites 3-methoxy-3-epiradicinol (4) and 9, 10-epoxy-3-methoxy-3-epiradicinol (5), and (2).
A s s m c r . A u l t u r e s of Alternaria chysantbtmi are known to produce the a-pyrones radicinin 111 and radicinol 121. During the course of a study to monitor the ability ofA. chyJantbtmi cultures to biotransform foreign substrates it was observed that the addition of foreign substrates stimulated the production of a third a-pyrone. This compound was identified as bisradicinin 131, a dimer of 1. Compound 3 was not produced in cultures of A. chysantknzi grown under identical conditions without added substrate. (Dematiaceae) is the etiological agent of leaf spot disease of Cbtysanthemwm maximum (Ram.) DC. (Compositae) (1). Early phytochemical analyses of A . chrysanthemi have led to the isolation and identification of two phytotoxic compounds, radicinin E17 and radicinol [27 (2,3). To date there have been no reports on the biotransformation of foreign chemical substrates by A . chrysanthemi, although unidentified strains of Alternaria have been reported to catalyze the deacylation of phenoxymethyl penicillin (4) and the reduction of progesterone to l-dehydroprogesterone ( 5 ) . As part of an ongoing study on the ability of A . chrysanthemi to biotransform foreign substrates we have recently identified 3, a novel dimer of radicinin. This compound was produced in all cultures used in biotransformation studies and was not observed in cultures grown under identical conditions but without added substrate.
Alternaria cbtysanthemi Simmons and CrosierHplc analysis of EtOAc extracts of the culture medium of A . chrysanthemi (over a 1 1 0 0 2 3
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