Abstract

Ganoderma lucidum is grown in the deep foliage of South-western China, where it is free from heavy metals and pollutions from populated cities. G. lucidum contains biologically active components, polysaccharides, which have been shown to enhance the immune system. In China, G. lucidum is commonly used to treat cancer, allergies, inflammation, hypertension and platelet-aggregation. This study investigates the proliferation, metabolism and cytokine secretion of lymphocytes in vitro upon G. lucidum stimulation. The powder of G. lucidum was provided by Mei Shan Tang Limited (Hong Kong) and tested to be free of heavy metals and microorganisms. Lymphocytes were extracted from 66 healthy human subjects and cultured with a pre-determined optimal concentration of G. lucidum (50-100 ug/mL) or a control medium for 72 h. Proliferation was measured with cell proliferation reagent, and metabolic rate was measured with ATP bioluminescence assay. Levels of IL-2, IL-4, IL-8, IL-10, GM-CSF and TNF-α were measured with ELISA. Meanwhile, toxicity was tested by feeding 70 rats with G. lucidum. No significant toxicity was detected in the rats. In human lymphocytes, G. lucidum was found to significantly increase cell proliferation and metabolism (p<0.05). T lymphocytes also demonstrated aggregation after G. lucidum treatment, which indicated T lymphocyte transformation. G. lucidum-treated cells also demonstrated a significantly increased secretion of IL-2, IL-8 and TNF-α (p<0.05). G. lucidum has the ability to enhance lymphocyte proliferation and metabolism without any significant toxicity in vitro. It also increases the secretion of cytokines, thus suggesting the potential of enhancing cellular immunity. G. lucidum is therefore potential candidate as a safe immunostimulant for patients on antin-eoplastic therapy.

Key words: Ganoderma lucidum, immune system, cell proliferation, cell metabolism, toxicity, cytokines.