Chemomicin A, a new angucyclinone antibiotic produced by Nocardia mediterranei subsp. kanglensis 1747-64.

A new angucyclinone antibiotic, chemomicin A was isolated from cultured broth of Nocardia mediterranei subsp. kanglensis 1747-64. Its chemical structure was determined to be 1,2,3,4a,5,6,6a,12a,12b-nonahydro-1,2,3,8,12,12b-hexahydroxy-3-methyl-6a,12a-epoxybenz[a]anthracen-4,7(12H)-dione by a detailed spectroscopic analysis. Chemomicin A had antimicrobial activity against Bacillus subtilis and Enterococcus faecium with MIC values of 10.2 and 20.4 microM, respectively, and showed cytotoxicity against human colorectal cancer HCT116 cells and human esophageal carcinoma YES-2 cells with IC50 values of 127 and 153 microM, respectively.