A new ascochlorin derivative from Cylindrocarpon sp. FKI-4602.

Cylindrol A₅, a new ascochlorin congener, was isolated along with 14 known compounds from the culture broth of Cylindrocarpon sp. FKI-4602 by solvent extraction, octadecylsilane column chromatography and HPLC. The structure of cylindrol A₅ was elucidated by spectral analyses, including NMR. The compound has an ascochlorin skeleton consisting of a resorcin aldehyde and a cyclohexanone moieties. Cylindrol A₅ showed moderate antimicrobial activity against Bacillus subtilis, Kocuria rhizophila, Mycobacterium smegmatis and Acholeplasma laidlawii. The biosynthetic pathway to cylindrol A₅ was deduced from the 14 isolated metabolites of the fungal strain.