Identification, Bioactivity, and Productivity of Actinomycins from the Marine-Derived .

In the process of profiling the secondary metabolites of actinobacteria isolated from the Saudi coastal habitats for production of antibiotics and anti-cancer drugs, the cultures of strain WH1 that was identified as exhibited strong antibacterial activity against . By means of MS and NMR techniques, the active compounds were characterized as actinomycins X, X, and D, respectively. The research on the productivity of this strain for actinomycins revealed that the highest production of actinomycins X, X, and D was reached in the medium MII within 5% salinity and pH 8.5. In this optimized condition, the fermentation titers of actinomycins X, X, and D were 107.6 ± 4.2, 283.4 ± 75.3, and 458.0 ± 76.3 mg/L, respectively. All the three actinomycins X, X, and D showed potent cytotoxicities against the MCF-7, K562, and A549 tumor cell lines, in which actinomycin X was the most active against the three tumor cell lines with the IC values of 0.8-1.8 nM. Both actinomycins X and D showed potent antibacterial activities against and the methicillin-resistant , and and the actinomycin X was more potent.