CJ-12,373, a novel topoisomerase II inhibitor: fermentation, isolation, structure elucidation and biological activities.

A novel isochroman carboxylic acid CJ-12, 373 was isolated from Penicillium sp. CL22557. CJ-12, 373 inhibits both DNA gyrase-mediated supercoiling and relaxation without the formation of a cleavage intermediate, suggesting that CJ-12, 373 inhibits DNA gyrase at a stage distinct from the religation step. CJ-12, 373 is not selective for procaryotic DNA gyrase as it also inhibits relaxation mediated by eukaryotic topoisomerase II. The antimicrobial potency of CJ-12, 373, however, is largely attributed to its inhibition of DNA gyrase.