Cytotoxic Activity of Fungal Strains Isolated from the Ascidian Eudistoma vannamei

Abstract The cytotoxic activity at 50 μg/ml of extracts obtained from eleven fungal strains associated to Eudistoma vannamei , an endemic ascidian from Northeast Brazil, against two cell lines, i.e. , the HCT‐8 (colon cancer) and the MDA‐MB‐435 (melanoma) cell lines, was investigated. The most promising extract ( EV10 ) was obtained from a fungus identified as Aspergillus sp. by molecular analysis and was selected for bioassay‐guided isolation of its active principals. Large‐scale fermentation of EV10 in potato‐dextrose broth followed by chromatographic purification of the active extract from the liquid medium allowed the isolation of the isocoumarins mellein, cis ‐4‐hydroxymellein, and trans ‐4‐hydroxymellein, besides penicillic acid. All isolated compounds were tested for their cytotoxicity against the tumor cell lines MDA‐MB‐435 and HCT‐8 and revealed penicillic acid as the only cytotoxic compound (cell growth inhibitions >95%).