Ganoderma lucidum, an oriental fungus (Figure 9.1), has a long history of use for promoting health and longevity in China, Japan, and other Asian countries. It is a large, dark mushroom with a glossy exterior and a woody texture. The Latin word lucidus means “shiny” or “brilliant” and refers to the varnished appearance of the surface of the mushroom. In China, G. lucidum is called lingzhi, whereas in Japan the name for the Ganodermataceae family is reishi or mannentake.

In Chinese, the name lingzhi represents a combination of spiritual potency and essence of immortality, and is regarded as the “herb of spiritual potency,” symbolizing success, well-being, divine power, and longevity. Among cultivated mushrooms, G. lucidum is unique in that its pharmaceutical rather than nutritional value is paramount. A variety of commercial G. lucidum products are available in various forms, such as powders, dietary supplements, and tea. These are produced from different parts of the mushroom, including mycelia, spores, and fruit body. The specific applications and attributed health benefits of lingzhi include control of blood glucose levels, modulation of the immune system, hepatoprotection, bacteriostasis, and more. The various beliefs regarding the health benefits of G. lucidum (Figure 9.2) are based largely on anecdotal evidence, traditional use, and cultural mores. However, recent reports provide scientific support to some of the ancient claims of the health benefits of lingzhi.

Lingzhi has been recognized as a medicinal mushroom for over 2000 years, and its powerful effects have been documented in ancient scripts (). The proliferation of G. lucidum images in art began in 1400 AD, and they are associated with Taoism (). However, G. lucidum images extended beyond religion and appeared in paintings, carvings, furniture, and even women’s accessories (). The first book wholly devoted to the description of herbs and their medicinal value was Shen Nong Ben Cao Jing, written in the Eastern Han dynasty of China (25-220 AD). This book is also known as “Classic of the Materia Medica” or “Shen-nong’s Herbal Classics.” It describes botanical, zoological, and mineral substances, and was composed in the second century under the pseudonym of Shen-nong (“the holy farmer”; ). The book, which has been continually updated and extended, describes the beneficial effects of several mushrooms with a reference to the medicinal mushroom G. lucidum (). In the Supplement to Classic of Materia Medica (502-536 AD) and the Ben Cao Gang Mu by Li Shin-Zhen, which is considered to be the first pharmacopoeia in China (1590 AD; Ming dynasty), the mushroom was attributed with therapeutic properties, such as tonifying effects, enhancing vital energy, strengthening cardiac function, increasing memory, and antiaging effects. According to the G. lucidum acts to replenish Qi, ease the mind, and relieve cough and asthma, and it is recommended for dizziness, insomnia, palpitation, and shortness of breath.

Wild lingzhi is rare, and in the years before it was cultivated, only the nobility could afford it. It was believed that the sacred fungus grew in the home of the immortals on the “three aisles of the blest” off the coast of China (). However, its reputation as a panacea may have been earned more by virtue of its irregular distribution, rarity, and use by the rich and privileged members of Chinese society than by its actual effects. Nevertheless, the Ganoderma species continue to be a popular traditional medicine in Asia and their use is growing throughout the world ().

The family Ganodermataceae describes polypore basidiomycetous fungi having a double-walled basidiospore (). In all, 219 species within the family have been assigned to the genus Ganoderma, of which G. lucidum (W. Curt.: Fr.) P. Karsten is the species type (). Basidiocarps of this genus have a laccate (shiny) surface that is associated with the presence of thickwalled pilocystidia embedded in an extracellular melanin matrix (). Ganoderma species are found all over the world, and different characteristics, such as shape and color (red, black, blue/green, white, yellow, and purple) of the fruit body, host specificity, and geographical origin, are used to identify individual members of the species (). Unfortunately, the morphological characteristics are subject to variation resulting from, for example, differences in cultivation in different geographical locations under different climatic conditions and the natural genetic development (e.g., mutation, recombination) of individual species. Consequently, the use of macroscopic characteristics has resulted in a large number of synonyms and a confused, overlapping, and unclear taxonomy for this mushroom. Some taxonomists also consider macromorphological features to be of limited value in the identification of Ganodermaspecies due to its high phenotypic plasticity (). More reliable morphological characteristics for Ganoderma species are thought to include spore shape and size, context color and consistency, and the microanatomy of the pilear crust. Chlamydospore production and shape, enzymatic studies and, to a lesser extent, the range and optima of growth temperatures have also been used for differentiating morphologically similar species (). Biochemical, genetic, and molecular approaches have also been used in Ganoderma species taxonomy. Molecular-based methodologies adopted for identifying Ganoderma species include recombinant (rDNA) sequencing (), random amplified polymorphic DNA-PCR (RAPD; PCR stands for polymerase chain reaction), internal transcribed spacer (ITS) sequences (), sequence-related amplified polymorphism (SRAP; ), enterobacterial repetitive intergenic consensus (ERIC) elements, and amplified fragment length polymorphism (AFLP; ). Other approaches to the problem of G. lucidum taxonomy include nondestructive nearinfrared (NIR) methods combined with chemometrics (), nuclear magnetic resonance (NMR)-based metabolomics (), and high-performance liquid chromatography (HPLC) for generating chemical fingerprints ().