# Nutritional Composition and Biological Properties of Sixteen Edible Mushroom Species
## 1 Introduction  
Mushrooms are considered to be functional foods with high nutritional, culinary, and pharmacological values [1]. Mushrooms have been recognized for the aforementioned values since ancient times. Ancient Greek warriors consumed mushrooms to increase their strength in battles, the Romans considered mushrooms as the food of the Gods, the Egyptians thought that mushrooms were a gift from [PERSON], and the Chinese used mushrooms in medicine and believed that they promote youth and health [2]. Mushrooms represent a global market of USD 63 billion, with 54% of this market being cultivated edible mushrooms, 38% medicinal mushrooms, and 8% wild mushrooms [3]. Worldwide mushroom production reached 10,378,163 metric tons in 2016 and the average per-capita consumption has grown considerably in recent years [4]. Specifically, global consumption of mushrooms has increased from 1 to 4.7 kg of cultivated edible mushrooms per capita from 1997 to 2013 [3]. China is currently the leading producer of cultivated edible mushrooms worldwide accounting for approximately 73 percent of the world's total mushroom production [2, 5]. The most cultivated mushrooms in the world are _Agaricus bisprouts, Lentinula edodes, Pleurotus_ spp., _Auricularia auricula-judae, Volvariella volvaca_, and _Flammulina velutiyes_[6]. On the other hand, the most famous wild mushrooms are _Boletus_, _catharellus_ spp., _Craterellus cornucopoides, Morchella_ spp., and _Marasmus oreades_[5]. Mushrooms form the three groups of fungi, Zygomycetes, Ascomycetes and Basidiomycetes. All three categories can grow both above the soil (epigeous) and below the soil (hypogeous) [7]. Fungi lack chlorophyll and the ability to utilize photosynthesis and thus are distinct from the plant kingdoms [4]. Most mushroom species' cultivation depends highly on environmental factors, such as temperature, air, and humidity, in order to grow optimally [4]. Traditionally, mushrooms are cultivated using outdoor log cultures, which have been used in China for over one thousand years. Nowadays, indoor cultivation in \"artificial logs\" is commonly used, which are plastic bags filled with nutrient-complemented sawdust-based substrates. The sawdust is held together like glue and when the bag is colonized it is unpacked to allow fruiting. Another similar cultivation technique is the column cultures, which are long plastic bags that are hung from the ceiling and once the mycelium colonizes the bags, holes are punched to allow mushroom fruiting [3]. Mushrooms are of high nutritional value due to the various nutrients they contain, such as protein, including essential amino acids, essential fatty acids, carbohydrates, dietary fiber, vitamins, and minerals [8]. In addition, there is a plethora of bioactive compounds in mushrooms, such as polysaccharides, polyphenols, terpenoids, lectins, alkaloids, sterols, glycoproteins, ergosterols, sesquiterpenes, and lactones [7]. However, the contents of these bioactive compounds may vary significantly depending on various factors, such as strain, substrate, cultivation, storage conditions, and processing [7]. Due to the aforementioned bioactive compounds, mushrooms exhibit a wide array of health-promoting properties including antioxidant, anti-cancer, immunomodulatory, anti-diabetic, neuroprotective, anti-hypertensive, hepatoprotective, anti-fungal, anti-microbial, anti-viral and anti-bacterial properties [9]. However, until recently the scientific understanding of mushrooms' medicinal properties has been primarily empirical [10]. There has been an increasing interest in advancing the health properties and pharmacological activities resulting in the growth of clinical research. Within this framework, much of the traditional knowledge on the issue is being documented and validated [11]. There is now an interdisciplinary field of science that studies medicinal mushrooms (MMs), accompanied by an increasing number of emerging human studies.