Ganoderma lucidum and its pharmaceutically active compounds

Abstract

Ganoderma lucidum is a wood-degrading basidiomycete with numerous pharmacological effects. Since the mushroom is very rare in nature, artificial cultivation of fruiting bodies has been known on wood logs and on sawdust in plastic bags or bottles. Biotechnological cultivation of G. lucidum mycelia in bioreactors has also been established, both on solid substrates and in liquid media by submerged cultivation of fungal biomass. The most important pharmacologically active constituents of G. lucidum are triterpenoids and polysaccharides. Triterpenoids have been reported to posses hepatoprotective, anti-hypertensive, hypocholesterolemic and anti-histaminic effects, anti-tumor and anti-engiogenic activity, effects on platelet aggregation and complement inhibition. Polysaccharides, especially β-d-glucans, have been known to possess anti-tumor effects through immunomodulation and anti-angiogenesis. In addition, polysaccharides have a protective effect against free radicals and reduce cell damage caused by mutagens.

Introduction

Ganoderma is a white rot wood-degrading basidiomycete with hard fruiting bodies. G. lucidum (W.Curt.:Fr.) Lloyd and Ganoderma applanatum (Pers.) Pat. (Aphyllophoromycetideae) are two species most often reported as a source of medicinal compounds. In Asian traditional medicine, the fruiting body of G. lucidum (Fig. 1), called Ling-Zhi in Chinese and Reishi in Japanese language, has been used for treatment of several diseases for thousands of years, as reported in Shen Nong's Materia Medica 1., 2.. However, an increasing systematic research (Fig. 2) into the Ganoderma active compounds elucidates its numerous pharmacological effects, such as antitumor, immunomodulatory, cardiovascular, respiratory, antihepatotoxic and central nervous system effects. Modern uses of Ganoderma therefore include treatment of coronary heart diseases, arteriosclerosis, hepatitis, arthritis, nephritis, bronchitis, asthma, hypertension, cancer and gastric ulcer 1., 3.. Publications also report on Ganoderma antiallergenic constituents [4], immunomodulatory action 5., 6., antitumor activity [7], cardiovascular effects [8], liver protection and detoxification, and effects on nervous system [9]. New reports emphasize its potential in treatment of viral, especially HIV infections 10., 11., 12., 13., 14., 15..

G. lucidum is very scarce in nature. As the demands of international markets for G. lucidum fruiting bodies and/or mycelium biomass are in constant increase, an artificial cultivation has become essential. Successful farming on wood logs and in bags filled with wood or straw substrates has been known for decades, especially in China. Biotechnological cultivation in bioreactors on solid substrates, or with submerged liquid substrate cultivation has been developed and introduced for small and pilot-plant production 16., 17., 18., 19., 20.. The quality and content of physiologically active substances vary from strain to strain, and also depend on location, culture conditions [21], the growth stage of the fungus [22], the processing procedures, and formulation preparation [23].

Diverse groups of chemical compounds with pharmacological activity have been isolated from the mycelium and fruiting body of Ganoderma species: triterpenoids, polysaccharides, proteins, amino acids, nucleosides, alkaloids, steroids, lactones, fatty acids and enzymes 1., 3.. The most important pharmacologically active constituents of Ganoderma mushrooms are triterpenoids and polysaccharides.