Perylenequione Derivatives with Anticancer Activities Isolated from the Marine Sponge-Derived Fungus, Alternaria sp SCSIO41014

Seven new secondary metabolites classified as two perylenequinone derivatives (1 and 2), an altenusin derivative (3), two phthalide racemates (4 and 5), and two phenol derivatives (6 and 7), along with twenty-one known compounds (8-28) were isolated from cultures of the sponge-derived fungus, Alternaria sp. SCSIO41014. The structures and absolute configurations of these new compounds (1-7) were determined by spectroscopic analysis, X-ray single crystal diffraction, chiral-phase HPLC separation, and comparison of ECD spectra to calculations. Altertoxin VII (1) is the first example possessing a novel 4,8-dihydroxy-substituted perylenequinone derivative, while the phenolic hydroxy groups have commonly always substituted at C-4 and C-9. Compound 1 exhibited cytotoxic activities against human erythroleukemia (K562), human gastric carcinoma cells (SGC-7901), and hepatocellular carcinoma cells (BEL-7402) with IC50 values of 26.58 +/- 0.80, 8.75 +/- 0.13, and 13.11 +/- 0.95 mu g/mL, respectively. Compound 11 showed selectively cytotoxic activity against K562, with an IC50 value of 19.67 +/- 0.19 mu g/mL. Compound 25 displayed moderate inhibitory activity against Staphylococcus aureus with an MIC value of 31.25 mu g/mL.