Derivatives of Holomycin and Cyclopropaneacetic Acid from Streptomyces sp. DT‐A37

On the basis of the one strain-many compounds strategy, five compounds including two new holomycin derivatives 2 - 3, two new cyclopropaneacetic acid derivatives 4 - 5, together with one known compound holomycin (1) were isolated from a marine-derived bacterium Streptomyces sp. DT-A37. Their structures were elucidated using NMR and HR-ESI-MS analyses. All these compounds were evaluated for their antimicrobial activity, cytotoxic activity, and inhibitory activity against BRD4 protein. Compound 1 exhibited potent cytotoxicity against H1975 cells with IC50 value of 1 μm, and its minimal inhibitory concentration values against Escherichia coli and Staphylococcus aureus were both 64 μm.