Traditional Chinese Medicine (TCM) has been used for thousands of years, during which time traditional knowledge originating in ancient China has been gradually developed further and distributed to Japan and other Asian countries. TCM relies heavily on the use of natural remedies including plants, animals, and even minerals to cure various diseases. However, in spite of the fact that the term “herbal medicine” is widely used to describe TCM and other ethnobotanical approaches for disease therapy, several mushrooms are commonly used as important ingredients. Furthermore, since fungal taxonomy has yet to be globally harmonized, there is considerable confusion concerning the identity of these important traditional “herbal” remedies. For instance, we will refer to “Ganoderma lucidum” as G. lingzhi, regardless of whether the authors of the respective cited papers had already adopted the modern taxonomy.
TCM has evolved through a combination of theory and practical experience of Chinese healers over many centuries. The first recorded use of Chinese medicine was during the Shang Dynasty in the eleventh century BC (1100–1001 BC), where even Ganoderma was recorded in detail and for the first time. However, the first comprehensive description of Chinese herbal remedies and their medicinal value was published in “Shennong Bencaojing (神农本草经),” during the Han dynasty (206 BC-220 AD). Later, another very comprehensive account of Chinese herbology, known as the “Bencao Gangmu (本草纲目)” or “Compendium of Materia Medica” (Sanodiya et al. 2009) was compiled by Li Shizhen (1518*1593) during the Ming Dynasty (1368–1644). In 1987, Chinese scientists compiled a list of 272 medicinal mushroom species (Ying et al. 1987). Later, this number increased to 799 species, 500 thereof with antitumor effects (Wu et al. 2013), and we estimate that about 850 species are presently being used as remedies in China. TCM has adopted a more holistic philosophy when compared with Western medicine (Wang et al. 2017). Chinese medicinal mushrooms have been used since the beginning of human history as a “protector herb” in order to maintain and enhance good health.
Whereas the majority of the TCM ingredients are derived from plants, several macrofungi have been included in the formulas. Some macrofungi are frequently included in TCM medicine formulas and are also very commonly sold in the medicinal or local markets. Notably, some, such as Ganoderma lingzhi and Wolfiporia cocos, are very expensive, while others such as Ophiocordyceps sinensis have become rare in nature (Sung et al. 2007; Zhang et al. 2012; Xiang et al. 2014; Hapuarachchi et al. 2018, 2019).
Ganoderma lingzhi (Lingzhi) contains both complex, high and low molecular weight natural bioactive compounds, which are mostly triterpenoids (Sandargo et al. 2019a). Bioactive compounds have shown in vitro activities against cancer cells, although none have been regarded as effective enough to enter clinical development as an ethical anticancer drug. Extracts of mycelial cultures and fruiting bodies of Ophiocordyceps sinensis and Cordyceps militaris primarily contain cordycepin, a derivative of nucleoside adenosine, with dimethylguanosine and iso sinensetin, and showed moderate anticancer and antiproliferative effects in vitro (Wong et al. 2010). Several bioactive compounds derived from mushrooms used in TCM were identified by bioactivity-guided fractionation. On the other hand, the potential therapeutic value of these fungal TCM products for the treatment of various diseases (e.g. cancer, diabetes, cardiovascular and neurodegenerative diseases) is even supported by clinical studies.
There has been intensive debate over the utility of TCM for modern healthcare. Many clinical scientists have doubted the utility of the classical TCM remedies because of their inaccurate descriptions, as well as the different philosophies regarding their therapeutic application. In fact, therapy for diseases in the Western world is mainly based on the application of single substances that have strong and selective biological and pharmacological activities, and must undergo very thorough clinical trials before they can be applied as therapeutic drugs. TCM, by contrast, often uses mixtures of preparations made from several plants, fungi and other organisms, each of which may contain dozens if not hundreds of different compounds. Therefore TCM does not really fit into the modern healthcare system (Fu and Yu 2005). However, the example of artimisinin shows that compounds from TCM can be very useful as remedies for diseases that have an unmet medical need. This terpenoid was originally found in the asteraceous traditional Chinese medicine plant Artemisia annua; a semisynthetic derivative, artesunate, is now on the market as a last generation antimalaria drug (the inventor received the Nobel Prize for Medicine in 2015). This example shows that it is worthwhile to study the ingredients of traditional Chinese medicine plants using modern drug research methods in order to discover novel therapeutic agents. Several examples of beneficial compounds from mushrooms have found their way into exploratory drug research projects (Grothe et al. 2011).
In addition, the recent integration of TCM and modern medicine has begun to solve multiple worldwide health problems. Many databases were evaluated to advance scientific formulations, chemical analysis, potential approaches, and other health targets. The World Health Organization (WHO) has also released a standard series for developing traditional medicines across the world, including medicinal mushrooms (Tang et al. 2018). The discovery of biologically active compounds from medicinal mushrooms can impact the direction of future medical development, and also has broad market prospects in North America, Europe and other developed economies (Lee et al. 2012; Wang et al. 2017). This may also increase international exchange, leading to the unprecedented development of Chinese medicine in the western world (Zhu 2018).
Chinese medicines have been utilized within several alternative medicinal practices to introduce positive changes in order to provide better contributions for health care while developing future medicinal products for diseases and for use in therapy (Lin et al. 2015; Han et al. 2017). However, there are challenges to the development of TCM products, due in part to the nature of the therapeutic potential and the fact that the mechanisms of action are often unclear. Furthermore, the materials used often do not meet the requirements of quality control and standardisation (Wen et al. 2017), and hence they are difficult to register as prescription drugs. Many materials have not been tested thoroughly to the standards of western medicine and can therefore only be sold as over-the-counter drugs or even neutraceuticals. Many challenges still stand in the way towards international collaborative exchange for opportunities to develop TCM, thereby advancing it at the global level (Chen et al. 2016). The use of mushrooms is advantageous when compared with the plants used in TCM, since mushrooms can be produced biotechnologically under controlled conditions and with standards, making them easier to work with than species that have to be grown and harvested in nature. In conclusion, to achieve the global acceptance of TCM products, it will be necessary to conduct clinical trials based on high quality standardised materials.