*4.1.1 Antioxidant property of medicinal mushrooms*

The reactive oxygen (ROS) and reactive nitrogen species (RNS) produced from the normal cellular metabolism are generally very reactive as studied for most organic compounds, [11, 33]. They could have either adverse or beneficial effects on living or biological systems [80]. ROS are free radicals made of atoms or molecular fragments with one or more unpaired electrons in their atomic or molecular orbitals [33, 83]. They are naturally produced in the body, especially in organelles like the mitochondria, as intermediates in a variety of normal biochemical and physiological processes, contributing a significant role in many normal cellular processes [30]. However, at high doses, ROS and RNS contribute to the oxidative damage of biological macromolecules, such as DNA, proteins, and lipids of the cell membranes. The damage to cells initiated by the free radicals, especially the damage to DNA, may lead to a significant development of many diseases, such as cancer and other metabolic disorders [22, 69].

Free-radical scavengers are chemicals with the potential to react with free radicals and then neutralize them, thus reducing the damages caused by those *Medicinal Mushroom of Potential Pharmaceutical Toxic Importance: Contribution… DOI: http://dx.doi.org/10.5772/intechopen.103845*

reactive species [55]. Most living body cells produce antioxidant and repair systems that can protect the body against oxidative damage; however, these substances are not enough to prevent or repair the damage completely [30]. The body, therefore, requires the introduction of more antioxidant agents from the diet, which is fundamental for maintaining cell homeostasis and a stable a healthy organism [84]. Although synthetic antioxidants, such as butylhydroxytoluene (BHT), propyl gallate (PG) butylhydroxyanisole (BHA), and *tert*-butylhydroquinone (TBHQ ), have been generally used as antioxidant additives in foods for many years, their safety has always been of great public health concern [38], the reason for increased interest in natural antioxidants research.

Many researchers have studied antioxidant activities on extracts and isolated secondary metabolites from edible mushrooms using different tests *in vitro* to evaluate the total antioxidant activity, lipid peroxide inhibitory property, reducing power capacity, the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydroxyl radical scavenging properties, the ferric reducing antioxidant power, the nitric oxide (NO) scavenging activity, and the ABTS radical scavenging, and the superoxide radical, [13, 49]. A large number of results in the data mining, therefore, clearly indicates that several edible mushrooms have significant antioxidant properties due to their bioactive metabolites, such as polyphenols, polysaccharides, carotenoids, vitamins, and minerals nutrients [11, 19, 53].

#### *4.1.2 Hypocholesterolemic effects*

One of the common metabolic disorders such as cardiovascular disease is associated with atherosclerosis, low-density lipid (LDL) oxidation, and hypercholesterolemia, play a role in the regulation of the cholesterol level which is vital for the prevention and treatment of this disease [42, 83]. Edible mushrooms are important food for the management of atherosclerosis due to their high fiber content and low-fat content [16]. In addition, the incorporation of edible mushrooms in a natural hypocholesterolemic and anterosclerotic diet is commonly used in traditional medicine [85]. Studies on the cholesterol-lowering activities of mushrooms were studied in Japan in the early 1960s, and it was demonstrated that rats fed with high fat and high-cholesterol diet supplemented with 5% water of the fruiting bodies of *Lentinus. edodes* for 10 weeks, had a significant dose-dependent decrease in plasma cholesterol concentrations of the animals [31, 82]. The adenosine derivative lentinacin or lentysine, also known as eritadenine [2(R), 3(R)-dihydroxy-4-(9-adenyl)-butyric acid, was later isolated and identified to be one of the active hypocholesterolemic secondary metabolites in the shiitake mushroom [86]. Studies also showed that Eritadenine has been shown to reduce the serum cholesterol level in mice by the acceleration of the excretion of ingested cholesterol and its metabolic breakdown [9, 17, 86]. Eritadenine affects the metabolism of cholesterol, phospholipids, and fatty acids in rats [87]. The dietary supplementation of eritadenine is also considered to decrease phosphatidylcholine biosynthesis through the alteration of the phosphatidylethanolamine concentration [47, 88].

#### *4.1.3 Mushrooms as hypoglycemic agents*

Advanced research for traditional plant treatments for diabetes has shown that identified edible mushrooms are an ideal food for the dietetic prevention of hyperglycemia due to their high dietary fiber and protein and low-fat content [69, 89]. Studies have been conducted on the hypoglycemic activity of whole mushrooms and their

fruiting bodies and on mushroom bioactive molecules, including polysaccharides [24] and lectins [90] isolated from the fruiting bodies. In addition, the endo and exopolymers produced in submerged mycelial cultures have been reported to have a hypoglycemic effect [91]. The most common widely used animal models for the study of the hypoglycemic effects of mushrooms are rats and mice with insulin-dependent diabetes mellitus (IDDM), induced by streptozotocin (STZ), and genetically modified diabetic mice with non-insulin [13, 92].
