Plant growth-promoting and antimicrobial chloropyrroles from a rare actinomycete of the genus Catellatospora.

Two new chloropyrroles, designated catellatopyrroles A (1) and B (2), along with 2-(2'-hydroxybenzoyl)pyrrole (3), were isolated from a culture extract of an actinomycete of the genus Catellatospora. The structures of 1-3 were elucidated through interpretation of NMR and MS data. Compounds 1 and 2 are the first chloropyrroles substituted by an aliphatic acyl group at the 5-position. Compounds 1-3 promoted root elongation of germinated lettuce seeds at 1-10 μM. While all compounds inhibited the growth of Gram-positive bacteria, activity against Gram-negative bacterium Rhizobium radiobacter and yeasts Candida albicans and Saccharomyces cerevisiae was varied. Compounds 1 and 2 were moderately cytotoxic against P388 cells.