Bioactive compounds in Leucocalocybe mongolica Pharmacological and Therapeutic Applications

baohaiying2008@126.com Abstract Medicinal mushrooms have got much attention from biologists in the last decades. Leucocalocybe mongolica Imai remains one of the famous clinical and edible mushrooms used in traditional Chinese medicine and Mongolian medicine to treat various diseases. It also commonly consumes in Chinese and Mongolian daily dishes. Numerous biochemical components exist in L. mongolica, especially in the fruiting bodies include; polysaccharides, sterol, lectins, laccase, amino acids, terpenes, volatile compounds, and so on. These biomedical components possess a lot of medicinal properties and provide diverse therapeutical effects for human health, such as anti-tumor activity, antiproliferative activity, anti-diabetes properties, hypotensive effect, hepatoprotective effect, antioxidant activity, cardioprotective effect, and so on. However, this review's main objectives are to illustrate some basics about the bioactive components in L. mongolica and its pharmacological effects on the human body. In addition to giving forward some suggestions for future research on this medicinal of breast cancer MCF7 cells , proliferation of hepatoma HepG2 cells and HIV-1 reverse transcriptase.


Introduction
Mushrooms are a crucial economic section of Chinese biodiversity [1]. The edible mushrooms are good nutritional food due to low calories, carbohydrates, fat, sodium, and cholesterol-free food. These mushrooms can also provide many vital nutrients, such as proteins, vitamin D, fiber, niacin, riboflavin, potassium, and selenium. However, Leucocalocybe mongolica is an edible and medicinal mushroom growing in Inner Mongolia's grassland, the north side of China, and Russia's far east. It is called "Kou-mo" or "Bai-mo" in China, while the Mongolian citizens call it huragan-mug. Previously, Leucocalocybe mongolica has belonged to the genus Tricholoma (Fr.) Staude (Agaricales Basidiomycota) [2]. In the last decades, Tricholoma mongolicum S. Imai was moved from the genus Tricholoma to a newly established genus called Leucocalocybe, based on its molecular and morphological features [3]. L. mongolica has a short thick stem and white tiny spiny spores, the average size of spores (6.0 to 9.0 × 5.0 to 7.0 μM) (Fig. 1) [3]. However, L. mongolica consumes as edible food because it combines exquisite flavor and high nutritional value, which means this mushroom could be considered a cheap nutritional food source as a feasible alternative to meat for many countries. It possesses great economic and medicinal properties. Recently, L. mongolica Imai (LMI) got much attention from researchers due to its rich bioactive components, including polysaccharides, phenolic compounds, sterols, terpenoids, unsaturated fatty acids, alkaloids, and volatile components …… etc. [6]. L. mongolica is a vital source of many biomedical valuable compounds that provide brilliant therapeutic power for disease expectation and control and treat the botulism of injuries and detoxifications [5]. Modern pharmacological studies indicate that L. mongolica have different medicinal properties, including antitumor, antiangiogenic, immunomodulatory, antioxidant, anti-antidiabetic, antiinflammatory hypoglycemic, antifungal, antibacterial, and antiviral [6]. For instance, the fruit bodies have antitumor activity [6]. The Evenks eat it to strengthen the health and decrease the blood temperature.

Bioactive compounds
Bioactive compounds play a vital part in our body due to their biological activities and pharmacological applications. L. mongolica is rich in chemical components that have multimedical and nutritional effects. It has dietary compounds vitamins, protein, carbohydrates, fiber, fat, and minerals. an enormous number of bioactive components have been found from L. mongolica recently (e.g., polysaccharides, lectins, protein, laccase, phenolic compositions, steroids, and volatile compounds. [7] [8].
Several researchers used different methods to extract and purify polysaccharides from Leucocalocybe mongolica (Table 1). The first method, called Ultrasonic-microwave synergistic extraction (UMSE) uses power of 109.98 W, the ratio of water: the raw material (fruit body) is 21.62 ml/g, for 24.65 min. The yield of crude powder after purification by Sephadex G-100 chromatography was higher than DEAE-Cellulose 52 chromatography purification. The LMIP crude powder contains 73.92% carbohydrates, 1.92% glucuronic acid, and 1.13% proteins. The common monosaccharides in LMIP are glucose, mannose, arabinose, xylose, and rhamnose [23]. The second method is enzyme-assisted extraction using mixture of enzymes (pectinase 2.5%, papain 2.0%, and trypsin 1.5%). The recommended conditions in this method for LMIPs extraction as determined by RSM is 48.4 •C, the pH 5.4 for 132 min., the total lMIPs yield was 24.01%, under the above conditions. The purified LMIP crude powder contained carbohydrates (82.13%), uronic acid (1.85%), and proteins (1.82%). The GC results of polysaccharides showed the composition of rhamnose, arabinose, mannose, glucose, and xylose [26]. The third method is cellulase-assisted extraction; the optimal extraction temperature for this method is 50 ℃, the cellulase amount is 20g/ Kg mushroom powder, pH of 4.0, and extraction time is 127 min. The predicted polysaccharides yield was 190.1g/ kg crude. The total polysaccharides product under these conditions was 189.6 g/kg. The contents of the whole carbohydrates contents 886.4 g/kg, the uronic acid contents of 19.2 g kg−1, and protein contents 18.6 g kg−1. According to the GC results, the monosaccharides-content in the extract 4 were arabinose, xylose, glucose, mannose, and rhamnose [27]. The last extraction method provided by Wang et al., [7], which remains the popular and easier way to extract polysaccharides from L. mongolica, the liquid-solid ratio is 30 mL/g. The extraction temperature 93℃, for 300 minutes. The polysaccharide content under these conditions about 6.64%. The LC-MS results demonstrated that the composition of extracted LMPs is Dfructose, trehalose, D-mannose, galactose. and D-xylose [7].

Ergosterols
Sterols remain one of the major chemical components in all mushrooms with an antitumor effect. Sterols isolated and identified from L. mongolica composed of ergosta-4, 6, 8 (14), 22-tetraen-3-one (ET), and (22E, 24R)-ergosta-7, 22-dien-3β, 5α, 6β-triol (ED) (Fig. 3). However, ergosterol is the highest significant steroid's chemical raw material. It mainly exists in medicinal and edible fungi; one of the primary compounds for synthesizing vitamin D biosynthesis of steroids has recently impressed synthetic chemists. Partially due to the complexity of stereogenicity, the biological profile of its systems, and the way to form these compounds' precision and sensitivity [32], [33] , [34]. However, ED and ET's effect on tumor inhibitory rate, tumor weight, and organ indices have been studied in mice [9]. The control group showed an increase in the tumor volume to 2.6 cm or more within 15 days than the lively control group. The tumor weight average in both ED-and ET-treated groups were significantly low than the negative control group depending on the ergosterols dose. Furthermore, treated-groups showed a protecting activity toward the tumor-beared mice's spleen and thymus comparing with the non-treated group. The macroscopic tumor observation illustrated that ED and ET possess significant tumor inhibitory effect, positively related to the dose concentration increase. The treated groups also have a considerable tumor inhibition rate (91.78%) with reducing the thymus and spleen weights. Moreover, [35] successfully extracted ergosterol (the molecular formula of C28H44O) and ergosterol peroxide (molecular formula C28H44O3) from L. mongolica (Fig. 2).

Terpenes
Terpenoids isolated from mushrooms used as anticancer, anti-proliferation, and antiinflammatory properties. The anti-inflammatory activity of these fungal terpenoids has been evaluated using RAW 264.7 cell line in vitro. The results of the NF-κB inhibition signaling pathway showed a reduction of the pro-inflammatory mediators' generation [36]. Moreover, triterpenes isolated from other mushroom species gave similar inhibiting activity against the NF-κB signaling pathway [32]. The anticancer properties of mushrooms terpenoids were also studied in the macrophage U937. The results illustrated significant pro-apoptotic and antiproliferation effects depending on the time and concentration of the extracts associated with cytochrome C release to the cytosol, caspases-3, -8, -9 activation, the probability of mitochondrial membrane losing and PARP damaging. Terpenoid has been isolated from L. mongolica using ethanol 77.95% with the extraction temperature is 78.78 •c [37], However Terpenoids should be examined in an in vivo and in vitro model for test their potential to as antidiabetic and antitumor or prevent some disease

Peptide and proteins
Mushrooms have a thirty percent protein content higher than ordinary vegetables. Mushrooms produce many bioactive proteins and peptides. Some of these proteins don't have enzymatic activity (e.g., lectins, ribosome-inactivating proteins, and antifungal proteins). Others possess enzymatic activity such as laccases and proteases and an immense amount of single amino acids [38]. Nevertheless, [39] found that the dried mushroom's basidiocarps have higher protein content (42.2%) than the fermented mycelium by liquid fermentation (27.2%) than the fermented solid-mycelium (17.9%).
Protein can be extracted from L. mongolica by enzymatic hydrolysis using alcalase with substrate concentration 2% at 55 ℃, for 150 min. The enzyme/substrate ratio is 1.5%, the product is about mixture of proteins and polysaccharides. To remove the polysaccharides from this mixture, ethanol 65% can be used with the ratio of 3:1 (ethanol/extract). The final protein concentration under these conditions was about 32.10 % [40]

Lectins
Lectins are proteins-carbohydrates linked together. They are generally interrelated with glycolipids, polysaccharides, and glycoproteins located on the cell surfaces [41]. The lectins are considered useful tools to study cell surface structures [42]. Lectins have been used in many biological studies, such as in cancer research, bacteriological and embryological studies, tumor cells, membrane glycoconjugates, taxonomical studies, cell sorting, and sorting mutant, and isolation of membranes and serum glycoconjugates,…. etc. Moreover, many lectins showed antitumor and immunomodulatory activities and [43] [44]. Mushroom lectin studies were reported for the first time in the toxicity investigations study of fly agaric (Amanita muscaria) in 1910, Lectins were successfully isolated from many mushrooms, i.g., Inocybe umbrinella [45], Amanita pantherina, Amanita phalloides [46], and Chlorophyllum molybdites [47]. Beside that Two kinds of lectins (LML-1 and LML-2) isolated from L.mongolica mycelium molecular weights of these lectins about 36-38 K.D, both lectins offered hemagglutinating activities and this hemagglutinating activities were lactoseinhibitable. The composition of both two lectins revealed high content of Val, Thr, Gly, Asx, and Glx, while the His and Arg content were very low. the purafction method of lectin from L. mongolica fruite body is different to that from mycelia [48]. Both LML-1 and LML-2 caused proliferation inhibition of PU5-1.8 and P815 tumor cell in dose-dependent action but did not show any in vitro effect on P388D1 and S-180 tumor growth cell lines [43]. However, LML-1 and LML-2 presented many similar properties, including the inhibition rate by lactose doses, dimeric structure, thermal stability, and equal molecular weights. LML-2 influenced a more significant powerful hemagglutination effect and lower antiproliferative activity toward PU5-1.8 cells, particularly in the serum compared with LML-1[49]

Laccase
Laccase (benzenediol: oxygen oxidoreductase) is a polyphenol oxidase that considers a member of the multi-copper oxidases family [50][51] [52]. In 1883, laccases were discovered in Rhus vernicifera (Japanese lacquer tree). These enzymes are common in some fungi, bacteria, and plants in nature [53] [54]. A novel laccase isolated from L. mongolica mycelial pellet using different chromatographic fraction methods to reduce all the inactive proteins which contain the laccase (e.g., Ion-exchange chromatographies on Q-Sepharose, CM-cellulose, and DEAE cellulose, and gel purification on Superdex 75) [6]. The extracted laccase from L. mongolica was found as one band on the SDS-page (66 kDa molecular mass) within the molecular masse range of other mushroom's laccases. It also is greatly stimulated by Cu2+ ions and inhibits by Hg2+ ions [43]. laccase from mushroom possesses some possible pharmacological features and clinical studies' as antiproliferative efficiency against the tumor cells and the inhibition capability against HIV-1 reverse transcriptase. antiproliferative property, also used in industrial, biotechnological, and environmental approaches, particularly in aromatic contaminants enzymatic digestion [55], [56]. In addition L. mongolica laccase has antiproliferative activity against HepG 2 cells and MCF 7 tumor cells [49].

Medicinal Activities
L. mongolica is a rich mushroom in bioactive components that offer health benefits like various cell protections and disease treatment. So, L. mongolica has many medicinal properties, including antitumor activity, antiproliferative activity, antioxidant activity, and atherosclerosis risk reduction. And it reduces blood pressure and cholesterol [62].

Antitumor
There were preclinical and clinical studies that mention mushrooms' effect on cancer cells because of their antitumor and anticarcinogenic activities [8]. Many parts in the mushroom showed antitumor activity, especially the fruit body [63]. Leucocalocybe mongolica possesses a robust antitumor activity. Research study illustrated that two ergosterols (ET and ED) from L. mongolica fruit body were treated tumor-infected mice for 14 days with dose (0.025, 0.05, 0.1 mmol /kg) could enhance the antitumor activity and reduce the generation of tumor angiogenesis through decreased VEGF and Bcl-2 proteins and increase BAX protein expression and by activating the caspase family of proteins in H22 tumor-infected mice. The highest antitumor percentage in the ergosterols-treated groups were 39.741% and 30.26% for ET and ED, respectively. ET and ED caused significant inhibition of the growth of HepG2, MCF-7 and HeLa cells in a dose-dependent matter in vitro. The IC50 of ED on the HepG2, MCF-7 and HeLa cells were significantly higher than ET [58]. Another study by [64] revealed that the ergosterol peroxide (5 mg/kg) and petroleum ether extract (35 mg/kg) from L. mongolica fruit bodies inhibited the tumor rates in H22-bearing mice by 67.15%, and 69.61%, respectively. Further, the ergosterol and ergosterol peroxide inhibited the division of HepG2 cells and induced apoptosis as well, the ergosterol and ergosterol peroxide showed an apoptotic rate of 41.2% and 42.33%, respectively, at the earlier stage.
The antitumor activity of polysaccharides from L. mongolica has been found in several ways, like macrophages activation and stimulating macrophage antigen-presenting activity which plays an essential role in enhancing T-cell propagation and inhibit sarcoma 180 tumor cells growth in rats [65]. Several authors have posited polysaccharides as antitumor agent depends on their chemical compositions, branching, and molecular weight [8], [31]. However, the polysaccharide-treated mice for two weeks with doses (100, 200 and 300 mg/kg) displayed a significant inhibitory effect on tumor growth in H22 tumor-infected mice comparing with the model group. The polysaccharides inhibited the Hela cell's growth in dose-dependent activity [28]. Also, [66] reported that polysaccharides from L. mongolica at the doses of 100, 200 and 300 mg/kg for ten days significantly inhibited the tumor cell by downregulation VEGF, Bcl-2 and upregulation of BAX protein as well as increase the apoptosis rate in dosedependent effect. Overall, Polysaccharides provides the antitumor impact through increasing the expression of BAX protein and decreasing the expression of VEGF and Bcl-2 proteins through activating the caspase family proteins in the tumor-bearing mice, in addition to enhancing the expression rate of PI3K/AKT and p-AKT/AKT [33] (Fig.3 ). The PI3K/AKT rate plays a vital role in the mechanism of antiapoptosis where PI3K provides a phosphate group to AKT forming p-AKT, which can regulate the cell apoptosis's substrate proteins directly or indirectly via phosphorylation [67]. The polysaccharide-peptide complex at dose 10 mg/mL prevented the proliferation of P815 mastocytoma cells in vitro [65]. 9 . Some research articles presented that lectins own an antitumor activity. Two lectins extracted from L. mongolica demonstrated antiproliferation activities by inhibiting the growth of monocyte-macrophage PU5-1.8 cells in mice by 52 % when treated by (40 µg/mL) for 48 h. but did not offered in vitro inhibition for sarcoma 180 cell's growth [40]. Another experiment by [53] revealed that the treatment of the tumor-bearing mice with lectins (LML1 and LML2) with dose of 5 mg/kg for 20 days decreased the growth of sarcoma 180 cells implanted in mice by 68.84% and 92.93% respectively compared with the tumor-beared control group [7]. Article published by [53] illustrated that L. mongolica Laccase exhibited potent antiproliferation activity against Hep G2 cells, breast cancer cells and inhibited HIV-1 reverse transcriptase; the IC50 values were 1.4 µM, 4.2 µM, 0.65 µM, respectively. Also, LML showed strong suppression toward tumor cell proliferation, especially breast cancer, without any additional cytotoxicity in vitro tests [7] and [68]. The lectins from the mycelium dose of 5 mg/kg /day for 20 days enhanced nitrite ion production and activating macrophages in mice to produce macrophage activation and tumor necrosis factors [7]. Overall, L. mongolica possesses a strong anticancer activity toward several cancer cell types (Table 3). So, different compounds could become potential candidates for cancer disease treatment.

Immune activity
Many previous studies evaluated the effects of lectins on the immune system. For instance, the injections of 10 μg lectins in intraperitoneal tissue for ten days upregulated the transforming growth factor-β, interleukin (IL)-1β, and nitric oxide synthetase expression level [69]. The immunomodulatory properties of L. mongolica are due to its rich bioactive compounds. The primary chemical compounds responsible for immune activity in L. mongolica are lectins, terpenoids, and polysaccharides [70]. Anywise, T cells are the vital type of white blood cells in the immune system that play a critical part in adaptive immunology response. It's easy to distinguish T cells from the other lymphocytes by their receptors on the cell surface [65]. The polysaccharide-peptide complex at dose 6 to 50 µg/mL treated for one week had immunomodulatory properties by enhancing nitrate ion production by macrophages activating factor, macrophage production the proliferation of T-cells in the normal BALBIc and C57BLI6 mice [65]. Some authors confirmed that polysaccharides extracted from solid-state fermentation of L. mongolica promote the immune system through increasing spleen and thymus weight and enhancing monocyte-macrophage phagocytosis [66]. Another study demonstrated the in vitro treatment of polysaccharide-peptide complex at the dose of 10 mg/mL could immuneprotection activity by stimulating T-cell proliferation and macrophages to produce nitrite ion inhibiting the P815 mastocytoma cells [65]. Furthermore, L. mongolica polysaccharides (100, 200 and 300 mg/kg daily) motivated the immune system by protecting the thymus and spleen of tumor-infected mice comparing with the control group, besides enhancing the production of IL-2, IL-6, IL-1β, and TNF-α [33]. The high dose of polysaccharide from L. mongolica fruit bodies could significantly improve mice's immune function though enhance the average content of hemolytin and lysozyme in serum, the monocyte-macrophage phagocytosis, thymus and spleen weights [71]. On the other hand, an earlier study confirmed that, two ergosterols (ET and ED) from L. mongolica (100, 200 and 300 mg/kg/d for two weeks) enhanced the immunity via increasing the serum cytokines "TNF-α, IFN-γ, IL-2 and IL-6" in H22 tumorinfected mice and recovered both thymus and spleen compared with the negative control group. Also, the water extract, ethyl acetate extract and petroleum ether extract could increase the phagocytic percentage, phagocytic index and hemolysin production of macrophages, increase the levels of cytokines IFN-γ, IL-2, IL-4, and IgA, and significantly improve the pathological changes of thymus and spleen tissues in immunosuppressed mice compared with the control group [72]. L. mongolica lectins have immune-modulatory activities to motivate the macrophages to produce tumor necrosis factor and nitrite ion (NO − 2) in the treated mice. Lectins minimized the mice sarcoma 180 cells growth by 68.8% [7]. According the studies L. mongolica plays an important role to enhance immune system.

Hypotensive
Many studies demonstrated that L. mongolica lectin has a hypotensive activity for the normal intravenous injected rats. This investigation is similar to several reviews about other edible mushrooms' hypotensive activity [73]. However, exerted lectin from L. mongolica mycelium with a dose of (10 mg/kg BW) decreased the mean blood pressure in the arteries via stimulating the macrophages to produce nitric oxide, making effective rat aortic ring relaxation [7]. [74] documented that lectins could reduce blood pressure via enhanced EDRF (endothelium-derived relaxing factor). However, The main EDRF releasing from the endothelium is nitric oxide. The reduction of blood pressure produced by lectin treatment did not return to its initial value, indicating its continued hypotensive activity, which was not affected by the lactose [74] [40].
Lectins from L. mongolica provided a significant inhibition toward 3H-NECA binding to the receptors of adenosine A2 in bovine cerebra cortices. In contrast, no binding effect has been found between 3H-PIA and the receptors of adenosine A1. According to the pharmacological results, L. mongolica lectin's hypotensive activity may be due to the vasorelaxation through adenosine A2 and/or nitric oxide production receptors. L. mongolica lectin created a remarkable relaxing effect on mice's aortic rings. It may occur due to the interaction between LML with the adenosine receptors. Hence, this may explain the hypotensive response in mice [75]. On the other hand, methylene blue can eliminate L. mongolica hypotensive activity [7]. In conclusion, although lectin is the only compound studied as a hypotension reduction agent, polysaccharides could also be used due to their ability to increase nitric oxide production.

Anti-diabetic
Leucocalocybe mongolica is a high content fiber and low-fat and calories mushroom. It could be an ideal food for regulating the blood's cholesterol level to prevent diabetes, reducing blood pressure and cholesterol [62]. This nutritional fiber binds with cholesterol and lipids, which prevents them from absorbing in the intestine [76]. Previous studies have revealed that a polysaccharide from the fruiting body of L. mongolica (10 mg/kg for 13 days) could reduce plasma glucose level in a period-dependent matter, which was remarkably different from those at various time points [77]. Various active components isolated from L. mongolica (e.g., polysaccharides, proteins, laccase, lectins, phenolic substances, sterols, alkaloids, and terpenoids) have been illustrated to target different deranged carbohydrate metabolic pathways, thus decrease insulin and blood glucose levels in type two diabetic [78]. However, there are weaknesses in Leucocalocybe mongolica bioactive compounds for diabetic studies that need more in-depth work in this research point.

Liver and kidney Protection
Earlier studies have revealed that some polysaccharides from the fruiting body L. mongolica at a dose of 100, 200, and 300 mg/kg for two weeks could protect liver and kidney in the tumor-infected mice through decreased AST and BUN values compared with those in the untreated group [33]. However, aspartate aminotransferase (AST) is an essential indication of liver status. The increases in the number of substances of liver production indicate a dysfunction in the liver cell. Another experiment showed that treatment of tumor-bearing mice with ergosterols (ET and ED) at the dose of 100, 200, and 300 mg/kg two weeks enhanced liver and kidney protection through decrease AST and BUN levels compare with the control group in dose-dependent effect [58]. However, several publications informed that lectins in L. mongolica possess anti-pathogenic properties [53].

Antioxidant activity
Several studies evaluated the in vitro antioxidant assays of polysaccharides from L. mongolica using ferric reducing activity power FRAP, DPPH radical scavenging activity, the hydroxyl radical scavenging activity, reducing and infrared spectroscopy analysis assays. The antioxidative analyses indicated significant free radical scavenging activities. The antioxidative activities occurred in a dose-dependent matter [20] [28] [27]. [6] measured the content of flavonoids and phenols in the solid-state fermentation of L. mongolica. The flavonoids' content in the extract was 0.183 and 0.267, while phenols were 4.903, 6.975 before and after fermentation, respectively. Some studies have revealed that the L. mongolica water extract at a dose 1.2 mL/kg/d for 11 days significantly enhanced the activity of SOD and decreased the MDA value in the plasma [79]. Polysaccharides from L. mongolica showed a high antioxidant activity that could significantly inhibit the oxidative modification of LDL, apoptosis of VEC and vascular endothelial damage. Other studies indicated that water extract and ethanolic extract of L. mongolica (10, 20, 40 mL/kg) significantly improve the activity of SOD by 66.58% and reduce the content of MDA by 36.89% in the plasma. the antioxidant effect of water extract was higher than the alcohol extract [80].

Cardioprotective
Heart disease is closely linked to atherosclerosis, hypercholesterolemia, and lowdensity lipoproteins oxidation, so regulating the total cholesterol is necessary to prevent these diseases. However, due to its low fat and high fiber content, edible mushrooms have become an ideal food for the dietary reduction of atherosclerosis. Indeed, oriental medicine prescribes edible mushrooms in a regular antisclerotic and hypocholesterolemic diet [81]. L. mongolica fruit bodies' aqueous extract at dose 0.3,0.6 and 1.2 mL/kg for 11 days simulated cardioprotective through increasing superoxide dismutase ( SOD) activity, and decrease the level of creatine kinase, lower lactate dehydrogenase, creatine kinase MB and malondialdehyde in the myocardial tissue induced ischemic mice isoproterenol [79]. Furthermore, L. mongolica Imai Polysaccharides possess high antioxidant activity which can inhibit the oxidative modification of LDL and vascular endothelial cells apoptosis. Therefore, LMIPs can reduce the hazard of LDL oxidation, cardiovascular disease, and hypercholesterolemia [27].

Antimicrobial activities
Antimicrobial is a term that involves a wide range of pharmaceutical materials, including; antifungal, antibacterial, anti-parasitic, and antiviral medicines [82]. Bacterial infection treatment is a critical matter. Although many antibiotic drugs are using recently (e.g., oxazolidinones, lincosamides, blactams, quinolones and aminoglycosides), repeating these microbial treatment infections by the same antibiotic makes the microorganism produce new resistant strains to this antibiotic [83]. Therefore, the discovering of new antibiotics remains one of the most fundamental challenges facing scientists. There were five main ways for the antibiotics to exert their effect (1) Alter the cell membrane's function and confusing the permeability so, the cations, nucleic acids, and other pigments get out from the cell and it dies; (2) prevent the cell wall formation by interfering the peptidoglycan synthesis, that will affect the cell wall inflexibility and solidity, which leads to cell death or lysis; (3) Interact with the polymerase complex in DNA replication and transcription. (4) Inhibit the synthesis of nucleotides or their derivatives; (5) Block the DNA expression [84]. Further, some antibiotics can inhibit protein-synthesizing via binding with one or both the 50S and 30S ribosomal subunits.
The antimicrobial activity of the bioactive component is mainly related to molecular weight. The low-molecular-weight compounds in L. mongolica are terpenes, steroids, while high-molecular-weight compounds are peptides and proteins. However, the low molecular weight compounds showed less antimicrobial activity than the high-molecular-weight compounds [85]. Some clinical studies indicate that petroleum ether extract of L. mongolica fruit bodies at concentration 50, 25 and 12.5 mg/mL exhibited potent antimicrobial activities against Escherichia coli ATCC8099 and Staphylococcus aureus and there were highly significant differences compared with the control group. The highest inhibitory effect was found in the dose of 50 mg/mL, with the inhibitory effect of 52.78% and 62.05%, respectively. In contrast, both ergosterol and ergosterol peroxide from L. mongolica at concentrations of 2×10 -2 and 1×10 -2 affected neither E. coli ATCC8099 nor S. aureus ATCC6538 [59].

Conclusion
Mushrooms are a vibrant organism in medicinal and nutritional value. They have a tremendous biological effect on the human body against many severe diseases. In Mongolia and China, Leucocalocybe mongolica got increasing importance last decades due to its high protein and fiber content and low amount of fats. Different bioactive compounds have been isolated from L. mongolica like polysaccharides, steroids, lectins, protein, and laccase, which demonstrated a significant pharmacological effect toward several diseases in vivo and in vitro (Fig. 4). However, the polysaccharide is one of the hottest research points in L. mongolica. Several studies mentioned that polysaccharides possess many potent clinical activities such as antitumor activity against different cancer cells (i.g. S-180 cells, Hela cells, PUS-1.8 and P815), immune activity, antidiabetic activity, antioxidant activity, and cardioprotective effect. The results showed brilliant effect as an antitumor agent, thus could become potential candidates for the prevention and treatment of cancer disease, but still need further anti-hypotensive and antimicrobial investigations. On the other hand, L. mongolica lectin has antitumor, hypotensive activity, immune activity, antidiabetic activity, anti-pathogenic properties. The effect of lectin on liver protection still not clear and need more studies. While, sterols demonstrated antitumor effects against different cancer cell lines HepG2, MCF -7, HeLa cancer cells, sarcoma-180, PU5-1.8, and P815 tumor cells, also used as an antidiabetic agent. Although L. mongolica is one of the best edible mushrooms with high nutritional value and multiple medicinal properties, just a few studies have been done on its pharmacological approach, especially its antioxidant activity many ingredients still didn't discover yet. Overall, L. mongolica needs more do in-depth research on the anti-diabetic, antioxidant, and antimicrobial activities as well as isolation and purification of the other compounds.