Ethyl acetate extracts of submerged cultured mycelium of higher basidiomycetes mushrooms inhibit human ovarian cancer cell growth

Higher Basidiomycetes mushrooms (HBM) are a well-known source of anticancer agents, yet few works have evaluated the effectiveness of HBM metabolites against ovarian cancer. In the present study, 22 strains of HBM belonging to 19 species were grown under submerged conditions. Biomasses were dried, ground, and extracted by three different organic solvents: chloroform, ethanol, and ethyl acetate in an attempt to extract low-molecular-weight substances. These 66 extracts were screened for their effect on the viability of ovarian cancer cells (ES-2) in vitro. Four ethyl acetate extracts of Coprinus comatus, Grifola frondosa, Hypsizygus marmoreus, and Phellinus igniarius were found to be most effective, with IC50 ≤ 25 μg/mL, and were used for further evaluations. It was found that all four ethyl acetate extracts were active against other ovarian cancer cell lines: SKOV-3 and SW-626. The results indicated that the ES-2 cells revealed more anticancer activity of the extracts, in comparison to SKOV-3 and SW-626 cells. The reduction in ES-2 cell survival reached almost 100% at a concentration of 75-100 μg/mL, in all cases, whereas the reduction in SKOV-3 and SW-626 survival, at the same concentrations, was 50%-70%. All selected extracts were tested for toxicity and were nontoxic at the tested concentrations. Our results show that ethyl acetate extracts of the HBM strains studied reduced the viability of human ovarian cancer cells.