The giant polypore, Meripilus giganteus (Pers.) P. Karst.
Agaricus aequivocus (Holmsk.) E.H.L. Kraus
Agaricus multiplex Dill.
Boletus acanthoides Bull.
Boletus giganteus Pers.
Caloporus acanthoides (Bull.) Quél.
Cladomeris acanthoides (Bull.) Quél.
Cladomeris giganteus (Pers.) Quél.
Clavaria aequivoca Holmsk.
Flabellopilus giganteus (Pers.) Kotl. & Pouzar
Grifola acanthoides (Bull.) Pilát
Grifola gigantea (Pers.) Pilát
Grifola lentifrondosa Murrill
Meripilus lentifrondosus (Murrill) M.J. Larsen & Lombard [as ‘lentifrondosa‘]
Merisma acanthoides (Bull.) Gillet
Merisma giganteum (Pers.) Gillet
Polypilus frondosus var. intybaceus (Fr.) Bondartsev
Polypilus giganteus (Pers.) Donk
Polyporus acanthoides (Bull.) Fr.
Polyporus acanthoides Rostk.
Polyporus aequivocus (Holmsk.) E.H.L. Krause
Polyporus frondosus Fr.
Polyporus giganteus (Pers.) Fr.
Polyporus lentifrondosus (Murrill) Murrill
The basidiomycete Meripilus giganteus occurs in the living trees of several genera, and causes a white rot of the butt and roots.
Fruiting body: annual; 50-80 cm diameter, pileate with fan-shaped to spathulate caps originating from a common base; aggregates of caps can be up to 1 m in diameter and 70 kg fresh weight; individual caps 10-30 cm diameter, 1-2 cm thick; upper cap surface cream white to yellow-brown, zonate; pore surface cream to yellow-orange-brown pores (3 to 5 per mm), rapidly turning blackish when bruised or cut.
Spores: 5.5-6.5 x 4-5 µm, subglobose, hyaline.
Edibility: edible, but with a sour taste and fibrous texture, palatability is questionable; younger, more tender specimens are to be preferred.
Habit and Habitat: on stumps of freshly felled trees and at the base of standing strees; often apparently growing from the ground, but always in contact with wood; circumboreal in the northern hemisphere, usually found on hardwoods, particularly horse chestnut (Aesculus), beech (Fagus), lime (Tilia) and oak (Quercus).
In the methanolic extract of Meripilus giganteus a mixture of saturated and unsaturated fatty acids (among them palmitic, oleic and linoleic acid) and ergosterol peroxide were identified as immunosuppressive components. Furthermore, a homologous series of straight-chained saturated hydrocarbons with 22 to 26 and 29 to 32 C-atoms were identified (Narbe et al.,1991). However, when tested for immunosuppressive activity, various mushroom extracts were not active in the assay system used (Koch et al., 2002). In these experiments, the assay was based on the ability of the extract to inhibit the binding of endotoxin to CD14+ cells and to influence LPS-induced release of proinflammatory cytokines (IL-1β, IL-6, TNF-α), regulatory cytokines (IL-2, IL-4, IL-10, IFN-γ), and the release of reactive oxygen species; these are physiological responses consistent with hypersensitivity reactions, like asthma.
A crude methanol extract from this species was shown to have significant cytotoxic activity against murine cancer cell line 3LL (Lewis lung carcinoma), with an IC50 of 19.8 ±2.6 µg/ml (Tomasi et al., 2004).
Narbe G, Lindequist U, Teuscher E, Franke P, Vainiotalo P, Basner R.
Studies of the chemistry of immunosuppressive active fractions from Meripilus giganteus (Pers ex Fr.) Karst.
Pharmazie. 1991 46(10):738-40.
Ohtsuka S, Ueno S, Yoshikumi C, Hirose F, Ohmura Y, Wada T, Fujii T, Takahashi E.
Polysaccharides having an anticarcinogenic effect and a method of producing them from species of Basidiomycetes.
UK Patent 1331513, 26 September 1973.