Abstract
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
Streptomyces heliomycini
exhibited strong antibacterial activity against
Staphylococcus aureus
. By means of MS and NMR techniques, the active compounds were characterized as actinomycins X
0β
, X
2
, and D, respectively. The research on the productivity of this strain for actinomycins revealed that the highest production of actinomycins X
0β
, X
2
, 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
0β
, X
2
, and D were 107.6 ± 4.2, 283.4 ± 75.3, and 458.0 ± 76.3 mg/L, respectively. All the three actinomycins X
0β
, X
2
, and D showed potent cytotoxicities against the MCF-7, K562, and A549 tumor cell lines, in which actinomycin X
2
was the most active against the three tumor cell lines with the IC
50
values of 0.8–1.8 nM. Both actinomycins X
2
and D showed potent antibacterial activities against
S. aureus
and the methicillin-resistant
S. aureus, Bacillus subtilis
, and
B. cereus
and the actinomycin X
2
was more potent.