**3. Carnivorous fungi**

They are fungi that are able to obtain most of their nutrients from trapping and eating microscopic animals [69]. They can develop a strong carnivorous feeding mechanism, and more than 200 species are well studied and documented. They belong to either the phyla Ascomycota, Mucoromycotina, or basidiomycota [70]. They are soildwelling mycorrhizal fungi and many species are capable of trapping the soil nematodes (nematophagous fungus), while others can invade amoeba or collembola [66].

This group of fungi species can grow on the epidermis, hair, skin, nails, or feathers of living or dead animals and thus known as dermatophytes instead of carnivores. Furthermore, fungi in orifices and the digestive tract of animals are neither carnivorous in nature, nor considered as internal pathogens [71]. The insects' pathogens that invade and colonize insects are called carnivorous if the fungal thallus is mainly in the insect as in the case of Cordyceps, or if it attaches to the insect-like in the case of the Laboulbeniales [72].

### **3.1 Common toxic mushrooms**

Most common mushroom species, such as *Amanita phalloides*, produce bioactive compounds that are toxic in nature, antibiotic, antiviral, hallucinating, or have the bioluminescent potential [73]. Although only a small number of deadly species have *Medicinal Mushroom of Potential Pharmaceutical Toxic Importance: Contribution… DOI: http://dx.doi.org/10.5772/intechopen.103845*

been reported, several other mushrooms have the potential to cause serious and unpleasant adverse effects. Mushroom toxicity can play a role in the protection of the function of the basidiocarp and the mycelium can possess considerable energy and protoplasmic material to develop a structure for spore distribution efficiency [42]. One major setback for the consumption of mushrooms is the production of toxins that makes the mushroom not suitable for consumption, by either causing side effects or symptoms like vomiting after the meal [74]. In addition, a report in 2008, on the ability of mushrooms to absorb heavy metals, radioactive substances, is an indication that some European mushrooms may have included toxicity from the 1986 Chernobyl disaster and many studies are still in progress [23].

#### **3.2 Psychoactive mushrooms**

Most mushrooms with psychoactive activities are known to play a vital role in traditional folk medicine worldwide. Psychoactive mushrooms have been used as a sacrament in rituals for mental and physical healing, and to facilitate visionary functions [24, 75]. One such ritual practice is the velada ceremony. A tradi-practitioner of mushroom use is called the *shaman* or *curandera* associated with a priest healer [76]. An example of a psychoactive mushroom *Psilocybe zapotecorum*, a hallucinating mushroom, is shown in **Figure 11**.

The Psilocybin mushrooms are also referred to as psychedelic mushrooms possessing psychedelic activity known as "magic mushrooms" or "shrooms." They are widely available in smart shops worldwide, or on the black market in countries that have outlawed their sale [11, 76]. Psilocybin mushrooms have been reported to facilitate a profound and life-changing effect often referred to as mystical experiences. Some scientific works have backed up these claims, as well as the long-lasting effects of the induced spiritual experiences [24, 77]. There are more than 100 psychoactive mushroom species of genus Psilocybe distributed worldwide. Psilocybin, a naturally occurring chemical in certain psychedelic mushrooms such as *Psilocybe cubensis*, has been studied for its ability in the treatment of psychological disorders, such as obsessive-compulsive disorder [77]. Small amounts have been shown to inhibit migraine headaches [78]. A double-blind study, done by the Johns Hopkins Hospital, showed psychedelic mushrooms promising potential to provide people an experience with substantial personal meaning and spiritual

**Figure 11.** Psilocybe zapotecorum *(hallucinogenic mushroom) [23].*


#### *Current Topics in Functional Food*



**223**

significance. In the study, one-third of the volunteers reported that the ingestion of psychedelic mushrooms was the single most spiritually significant event of their lives [79].

## **3.3 Mushroom bioactive metabolites of therapeutic potential**

Potential bioactive metabolites studied in medicinal mushrooms and their therapeutic potential against cancer are illustrated in **Table 2**. Secondary metabolites of higher fungi (mushrooms) are an underexplored resource compared to plantderived secondary metabolites. An increasing interest in mushroom natural products has been noted in recent years [34, 80]. The divergent biosynthetic pathways from farnesyl pyrophosphate to sesquiterpenoids are also described. Selected triterpenoids with novel structures and promising biological activities, including lanostanes and ergostanes, ergosterol are reported from the genus Ganoderma, and the fungi *Antrodia cinnamomea* and *Poria cocos* [81].
