Ganoderma lucidum and Its Components on the Functions of Macrophages

摘要

Ganoderma (G.) lucidum has long been used as a remedy for promotion of health and longevity in China. The most attractive nature of the fungus is its anti- tumor effect which was supposed to be the result of enhanced immune function. Macrophage is involved in many aspects of host defense mechanisms and numerous studies indicate that macrophage is one of the target cell types for Ganoderma polysaccharides. This review focuses on the effects of Ganoderma and its components on the functions of macrophages. Water extracts from fruiting bodies of G. lucidum and Ganoderma polysaccharides were shown to be effective in enhancement of phagocytosis of chicken red blood cells by the peritoneal macrophages in mice. Polysaccharides from G. tsugae restored the decreased clearance rate of charcoal particles in mice that had been pretreated with hydrocortisone. An injection of G. capense was shown to enhance the pinocytosis of neutral red and increase the content of lysozyme in the macrophages. Treatment of mice with water extract from G. lucidum spores resulted in a considerable increase in activities of lysozyme, acidic phosphatase and β-glucoronidase and promoted the formation of H<,2>O<,2>. It was demonstrated that one of the anti-tumor mechanisms of Ganoderma polysaccharides might be the enhancement of cytokine production by macrophages and lymphocytes stimulated by the polysaccharides and the cytokines, in turn, kill the tumor cells. In addition, we conducted a series of experiments to determine the involved signaling events in macrophages induced by a purified Ganoderma polysaccharide. The results showed that intracellular calcium, diacylglycerol (DAG), protein kinase C (PKC) and cyclic adenosine monophosphate (cAMP) might be responsible for the signal transduction.