Growth-Inhibitory and Immunomodulatory Activities of Wild Mushrooms from North-Central British Columbia (Canada)

Wild mushrooms, especially from North America, have not been systematically explored for their medicinal properties. Here we report screening for the growth-inhibitory and immunomodulatory activities of 12 species collected from multiple locations in north-central British Columbia, Canada. Mushrooms were characterized using morphology and DNA sequencing, followed by chemical extraction into 4 fractions using 80% ethanol, 50% methanol, water, and 5% sodium hydroxide. Growth-inhibitory, immunostimulatory, and anti-inflammatory activities of 5 mushrooms (Leucocybe connata, Trichaptum abietinum, Hydnellum sp., Gyromitra esculenta, and Hericium coralloides) are reported here, to our knowledge for the first time. Growth-inhibitory effects were assessed using the cytotoxic MTT assay. Immunostimulatory activity was assessed by tumor necrosis factor-a production in Raw 264.7 macrophages, whereas anti-inflammatory activity was assessed based on the inhibition of lipopolysaccharide-induced tumor necrosis factor-a production. The ethanol and aqueous extracts of Hydnellum sp. were potent growth inhibitors, with a half-maximal inhibitory concentration of 0.6 mg/mL. All 5 fungi displayed strong immunostimulatory activity, whereas only L. connata and T. abietinum showed strong anti-inflammatory activity. For the 7 other fungi investigated, which included well-known medicinal species such as Inonotus obliquus, Phellinus igniarius, and Ganoderma applanatum, the remarkable similarities in the biological activities reported here, and by others for specimens collected elsewhere, suggest that mushrooms can produce similar metabolites regardless of their habitat or ecosystem. This is to our knowledge the first study to explore wild mushrooms from British Columbia for biological activities that are relevant to cancer, and the results provide an initial framework for the selection of mushroom species with the potential for discovery of novel anticancer compounds.