Carboxylic acid microbial metabolites of the natural benzoquinone, maesanin

Maesanin (1) is a naturally occurring bioactive benzoquinone isolated from the fruits of Maesa lanceolata (Myrsinaceae). Three carboxylic acid metabol ites of maesanin were isolated in the course of a prospective microbial tra nsformation study. The first metabolite, 2, was produced by Lipomyces lipof er ATCC 10742 and was characterized as (Z)-15-(2'-hydroxy-5'-methoxy-3',6'- dioxocyclohexa-1',4'-dienyl)pentadec-5-enoic acid. Metabolites 3 and 4 were produced by Rhodotorula rubra ATCC 20129 and were characterized as 6-(2'-h ydroxy-5'-methoxy-3',6'-dioxocyclohexa-1',4'-dienyl)hexanoic acid and 4-(2' -hydroxy-5'-methoxy-3',6'-dioxocyclohexa-1',4'-dienyl)butanoic acid, respec tively.