Bioassay-Guided Purification of Cytotoxic Isoflavonoids and Sesquiterpenoids of Streptomyces coelicolor Isolated from Marine Sponge Axinella sinoxea, and In Silico Target Prediction.

Among 13 different bacterial isolates, four Streptomyces strains were cytotoxic thus selected for further biological and chemical analyses. The WAK 9 strain was different from other strains based on its HPLC. Since WAK 9 was molecularly separated from the others and had the highest cytotoxic properties among tested strains and for the presence of the rare terpenoids (4-8), and the butenolide (3) this strain may be interesting for further investigations. In silico investigation revealed the possible target of 5 and 6 and their activities in the presence of Hsp90-beta, which is an essential target in the tumor cells.