**1.1 Medicinal mushroom in phytotherapy**

From an evolutionary point of view, nature produces vast biodiversity of bioactive molecules, which possess many therapeutic potentials, with respect to the treatment of diseases, such as cancers [1, 8]. Natural products have produced many secondary phytochemical compounds widely used in phytotherapy, whilst the application of such products in folk and traditional medicine has always been an important clue pointing to potential new chemical entities with therapeutic potential. Some examples of plantbased compounds of pharmaceutical importance for cancer treatment include camptothecin derived from the bark and stem of the tree *Camptotheca acuminata* used in Chinese traditional medicine [2], vinca alkaloids derived from *Madagascan periwinkle* [9] or taxanes derived from genus Taxus (yews), paclitaxel (Taxol), and docetaxel (Taxotere) widely used as chemotherapeutic agents [3, 10]. Generally, first-generation natural chemotherapeutic properties are orientated mostly against housekeeping processes (such as DNA replication or microtubule polymerization and stabilization), which are very active against fast proliferating cancer cells, but not cancer specific [11]. The natural products derived from mushrooms may produce potential adverse side effects on ingestion when used in herbal or conventional anticancer treatments, thus could provoke an eventual patient's death when consumed in overdose. Currently, the approaches used in the management and control of cancer pathologies are based on selected or targeted treatment applications with the intention to reduce to healthy uninfected tissues [11]. The discovery and development of potentially bioactive molecules from mushrooms for better selectivity in action to diseases, especially those to act on cancer cells or on tumorigenic processes, are faced with challenges. It is of importance to develop high through put (HTP) methods for the discovery and potential screening of the bioactive compounds of pharmaceutical importance [12].

## **1.2 Medicinal mushrooms in folk medicine**

Mushrooms have been used in folk medicine as far back in ancient times [12]. Mushrooms species used varied in different cultures, in a way that more species have been identified and used in Asian countries than in the Western civilization [5, 13]. It is reported that the difference in usage is linked to the mycophilic and mycophobic nature of the different cultures [14]. In developed countries, the most common species and

*Medicinal Mushroom of Potential Pharmaceutical Toxic Importance: Contribution… DOI: http://dx.doi.org/10.5772/intechopen.103845*

possibly the only one that has been identified, at the time of the ancient Greeks, was *Fomitopsis officinalis*. Hippocrates was one of the pioneers to study the medicinal properties of fungi and elucidated their potential uses in the management of certain common diseases, however, it is not certain as to what species he studied. The contribution of Dioscorides, a physician around 55 AD, who was well known and recognized for his work entitled *De Materia Medica*, still stands as the most widely used herbal bioactive natural product during his era and for about 1500 years, he changed in a significant manner the nutraceutical concept of the Western world and played an important role in the use of mushroom as food and medicinal product, which was the onset of the science of nutraceuticals [15]. The work of Pliny and later Galen also studied and concluded that fungi were of medicinal and pharmaceutical importance. Their opinions, however, influenced the mycophobic nature of mushrooms in Western Society that continues, in the current day. However, *F. officinalis* was globally recognized among the medicinal plants that was used to treat various diseases. Other species used for medicinal applications were other bracket fungi; *Fomes fomentarius*, *Phellinus ignarius*, *Fomintopsis pinicola*, and others that were commonly used to stop the bleeding and as wound healing [7, 16]. In China, where mushrooms are known to be a part of the gastronomy and elixir of life, mushrooms have been considered to play an important role in medicine, nutraceutics for as far back as 7000 years. Many species of mushrooms are identified, including *Lentinula edodes*, *Hericium erinaceum*, *Flammulina velutipes*, *Auricularia polytricha*, and *Tremella fuciformis*, etc., and these are species that are very prized for eating [9, 17].

#### **1.3 Mushrooms as a delicacy food in Cameroon**

Mushroom is a delicacy for many around the world. In Cameroon, this crop (fungi) is harvested from the wild once a year during the month of April to May. This activity mobilizes many women and youths (girls and boys) who rely on it for income. Harvested mushrooms, mostly the Agaricus and the termitomyces species, are sold on the roadsides and more often by youths as it generates a substantial amount of money that is used to pay part of their school fees, buy school supplies, and even pay medical and telephone bills [18]. Many people in Cameroon solicit mushrooms because of their good taste, medicinal and nutritive value, cheap and available, especially during its peak season. During offseason, it is not the case. Mushrooms are practically absent in the market and very few traders (middlemen) are in possession of some bags of dry mushroom. A bucket (15 L) is often sold between 15,000 and 25,000 FCFA (\$30–\$50). A plate of mushrooms is very expensive in restaurants and hotels [19].

Cultivating mushrooms is a good business owing to its short production cycle and poor farmers or youths can easily start up a small farm if trained. This will put mushrooms on the table and in the market all year round generating a substantial amount of income to prospective growers. The government has not been very supportive of this activity and we still struggle to import mother spawns to produce base 2 cultured spawns that farmers use to grow mushrooms. In addition, many people are unaware of the different types of edible mushrooms, so there is inadequate sensitization. The absence of financial and technical support also contributes a great deal.

#### **1.4 Usage of medicinal mushrooms**

Most of the benefits of mushrooms studied and investigated through the scientific method are those that have been recognized to produce bioactive metabolites that


#### **Table 1.**

*Mushroom with immunomodulating bioactive compound [3, 19].*

inhibit or can destroy cancer cells development [18]. Most species that produce these bioactive compounds do so by the process of immunomodulation, the modification, by suppressing or enhancing the immune system, and is used in the treatment of cancerous growth [3, 19]. These compounds as illustrated in **Table 1** include Lentinan, Schizophyllan, D-fraction to name but a few.

Just a few species containing these bioactive metabolites have been studied, and over 30 species of mushrooms studied have been shown to have anticancer properties in animals [20]. PC-SPES, which includes a GLPS fraction, has been demonstrated to control adenocarcinoma of the prostate cancer cell line by inhibition of the cell division and growth of their cells [21–24]. This is a very simple and logical explanation of the mechanism. Various species of mushrooms have been reported as nutritious and tasty food in many parts of the world and have been documented by many researchers [24–26]. The nutritious property of mushrooms is also another means by which they can be beneficial to the health of the person consuming mushrooms [27].

Many researchers have demonstrated the medicinal and nutraceutical properties of mushrooms' bioactive compounds, for the management of different illnesses [28]. Despite the bioactive activity demonstrated none of the phytoactive compounds have had approval by the Food and Drug Administration (FDA) of USA, and therefore still considered under the category of dietary supplements, as opposed to the drugs approved by FDA that are prescribed or used as over-the-counter drugs, failing to have undergone any clinical trials studies [29–31]. This category of supplements is marketed with the condition to carry the label of not being approved for use by the FDA [32].
