collismycin a

Collismycin A is a bacterial metabolite from *Streptomyces* with antibacterial, antiproliferative, and neuroprotective properties. It exhibits activity against various bacteria (MICs = 6.25-100 μg/ml) and fungi (MICs = 12.5-100 μg/ml). It inhibits proliferation of A549 lung, HCT116 colon, and HeLa cervical cancer cells (IC50s = 0.3, 0.6, and 0.3 μM, respectively) and NIH373 fibroblasts (IC50 = 56.6 μM) but not MDA-MD-231 breast cancer cells (IC50 > 100 μM). Collismycin A forms a complex with Fe(II) and Fe(III) in a 2:1 ratio, with iron ions inhibiting its antiproliferative effect on HeLa cells, an effect not observed with zinc, manganese, copper, or magnesium ions. Additionally, Collismycin A (1 μM) reduces apoptosis in zebrafish larvae brain regions by 44% in a model of neuronal cell death induced by all-trans retinoic acid.

Collismycin B is an effective dexamethasone-glucocorticoid receptor inhibitor with an IC50 value of 10 µM, and it exhibits both antibacterial activity and cytotoxicity.