Pradimicins L and FL: new pradimicin congeners from Actinomadura verrucosospora subsp. neohibisca.

Pradimicin L, a new congener of pradimicin A having the D-glucosyl-D-thomosamine moiety at the C-5 position, was isolated from Actinomadura verrucosospora subsp. neohibisca subsp. nov. The structure of pradimicin L was deduced to be N-[[(5S,6S)-5-O-[4,6-dideoxy-4-(methylamino)-3-O-(beta-D-glucopyranosyl) - beta-D-galactopyranosyl]-5,6,8,13-tetrahydro-1,5,6,9,14-pentahydroxy-11- methoxy-3-methyl-8,13-dioxobenzo[a]naphthacene-2-yl]carbonyl ]-D-alanine by MS and NMR spectrometry and degradation studies. Pradimicin FL which has the D-serine moiety instead of D-alanine was produced by directed biosynthesis in D-serine-supplemented medium. Pradimicins L and FL have a broad spectrum of in vitro antifungal activity. Pradimicin L was equiactive to pradimicin A and pradimicin FL was more active than pradimicin L.