Medicinal Mushroom Extracts Possess Differential Antioxidant Activity and Cytotoxicity to Cancer Cells

Many species of edible mushrooms are known to contain a wide array of compounds with high nutritional and medicinal values. However, these values vary widely among mushroom species because of the wide diversity of compounds with different solubilities to solvents used in extraction. We report here the comparison of antioxidant activity and cytotoxicity against cancer cells in extracts of Pleurotus ostreatus, P. sajor-caju, Agaricus campestris, and A. bisporus from 7 different solvents, including water, ethanol, ethyl acetate, acetone, chloroform, hexane, and petroleum ether. The extracts were analyzed for their antioxidant activities using the % DPPH (2,2-diphenyl-1-picrylhydrazylhydrate) scavenging activity method. Our results revealed that the water extracts exhibited the highest % DPPH scavenging activity in comparison to all other solvent extracts. The highest value was obtained from the water extract of P. sajor-caju (78.1%), and the lowest one was from the hexane extract of A. bisporus (0.8%). In general, extracts from nonpolar solvents exhibited much lower antioxidant activities than those from polar solvents. The cytotoxic effects of these extracts were evaluated using 2 cancer cell lines of larynx carcinoma (HEp-2) and breast carcinoma (MCF-7). When added into Hep-2 cells, the hexane extracts from P. ostreatus, P. sajor-caju, A. bisporus, and A. campestris yielded the highest IC50 values of 1.7 ± 1.56, 2.1 ± 2.82, 4.4 ± 1.71, and 2.2 ± 1.34 μg/mL, respectively, in comparison to all other solvent extracts. Similar IC50 values were obtained when the MCF-2 cancer cells were tested, suggesting that hexane is the preferred solvent to extract the anticancer compounds from these mushrooms. Our results also indicated that extracts from solvents with nonpolar or intermediate polarity were more potent than those with high polarity in their cytotoxicity against cancer cells, and extracts from different mushrooms by the same solvent possessed varied degrees of cytotoxicity.