A New Polyunsaturated Acid from the Marine-Derived Streptomyces violans (No. HTTA-F04129)

One new polyunsaturated acid (1), together with two known compounds, benzodipyran (2) and 7-hydroxy-2(2-hydroxypropyl)-5-methylchromone (3) were isolated from the fermentation broth of the marine Streptomyces violans (strain HTTA-F04129). Their structures were elucidated on the basis of 1D and 2D NMR, HR-FAB-MS spectra, and IR spectra. Bioassay results showed that compound 1 possessed significant selective antitumor activity against A2780 cell line in vitro with IC50 value 4.36 M and antibacterial activity against E. coli with MIC value of 25 g/mL.