**1. Introduction**

Medicinal mushrooms and fungi are known to contain more than 120 medicinal properties, which include antitumor, anti-hypercholesterolemic, antiviral, antibacterial immunomodulation, antioxidant, free radical scavenging, cardiovascular, anti-parasitic, antifungal, detoxification, hepatoprotective, and antidiabetic properties [1]. Most of the Basidiomycetes mushrooms contain bioactive metabolites in

fruiting bodies, cultured mycelium, and cultured broth, with special consideration to mushroom polysaccharides [2]. Studies on mushroom polysaccharides and different bioactive metabolites have been done for more than 700 species of higher hetero- and homobasidiomycetes [3]. Many bioactive metabolites from the medicinal mushrooms studied are known to enhance innate and cell-mediated immune responses, and exhibit antitumor activities in animals' models and clinical trials studies in humans [2, 4]. Even though the mechanism of antitumor properties of medicinal mushrooms is yet to be well understood, stimulation and modulation of major host immune responses by these mushroom bioactive are important [5]. Polysaccharides and lowmolecular-weight secondary metabolites are very important due to their antitumor and immune-stimulating activities, based on Phase I, II, and III clinical trials. Mushroom compounds have been used extensively and successfully in low medium-income countries for the treatment of many categories of cancers and other pathologies [6]. More exploration has been directed and special emphasis orientated to investigate many important unsolved problems in the study of medicinal mushrooms [7].
