In this issue of Mycosystema, ten papers dealing with eight important medicinal fungi are presented, including four review papers and six original study papers. The summarizing papers focus respectively on prospects, current research and development, chemical constituents and pharmacological effects of Cordyceps s.l., Irpex lacteus and Polyporus umbellatus. The research papers deal with proteome analysis on sclerotium of Polyporus umbellatus, sterone content determination and fingerprint analysis of P. umbellatus, MC-UVE wavelength selection method in the identification of Wolfiporia cocos based on NIR spectroscopy, effects of light and pH on the antioxidant activities of Trichaptum biforme, antioxidant activities of Sanghuangporus sanghuang during the liquid cultivation, and effects of antinocieptive compound from Ophiocordyceps sobolifera on the transcriptome pain-related genes in gouty rats. These reviews and research papers represent the most updated research progress of Cordyceps militaris, Cordyceps s.l., Irpex lacteus, Ophiocordyceps sobolifera, Polyporus umbellatus, Wolfiporia cocos, Trichaptum biforme and Sanghuangporus sanghuang in China, and provide very important data on Chinese medicinal studies.
N6-(2-hydroxyethyl)-adenosine (HEA), isolated from cultured mycelia of Cordyceps species, is the first calcium antagonists from biological sources. HEA has become a research hotspot because of the activity of inhibiting proliferation of tumor cell, restraining flammatory activity, protection of kidney and sedative activity, and so on. This paper reviews the research progress on HEA of fungal sources, concerning its physiological function, biosynthesis, extraction and purification, and chemical synthesis. The patents for HEA have also been analyzed and evaluated. It is suggested that exploring HEA of fungal sources, optimizing the method of extraction and purification as well as deepening the research on biosynthesis pathway will be conducive to the theoretical study and exploitation of HEA.
Cordyceps militaris as a fungal resource for medicine and food has already been known and accepted widely. Based on current situations both of research and industry of C. militaris, this paper points out some problems we are facing and gives analysis and discussion. Trends of research and development in the future are also predicted and valued. This paper emphasizes some important and neglected aspects concerning C. militaris and other related Cordyceps sensu lato fungi, aiming at providing references for future research and exploitation of related fungal resource.
Irpex lacteus is one of the medicinal fungi and its polysaccharides have been developed into medicine used for nephritis treatment. The studies on the mycelial culture, fruiting body cultivation, extraction and function of polysaccharides, ectoenzyme and its application are reviewed in this paper. The patents and applications concerning I. lacteus products at home and abroad are compared and analyzed. The major challenges existing in the current study on this fungus are discussed and some recommendations for the future development are proposed.
Polyporus umbellatus is a kind of edible-medicinal fungus and its sclerotia have been used as medicine for more than 2 000 years in China. The research progress on chemical constituents and pharmacological effects of sclerotia of P. umbellatus was reviewed in this paper.
N6-(2-hydroxyethyl)-adenosine (HEA) separated and purified from the artificial cultivation of Ophiocordyceps sobolifera was confirmed to be responsible for analgesia of acetic acid-stimulated mice. The mRNA expression of synovium from gouty rats treated with or without HEA was compared by transcriptome sequence and 932 differential expressed genes (DEGs) were obtained. Comparison of these 932 DEGs with the pain gene database, where the genes were changed during pain, 57 genes were supposed to be highly potential to participate in the regulation of pain. According to related reports, 12 antinocieptive genes were obtained including up-regulated adenosine A1 receptor (A1R, Adora1) and A2A receptor (A2AR, Adora2a). The result of Western blot showed that A1R and A2AR, the regulated target of pain, were markedly increased and decreased respectively in HEA group (7.5mg/kg) as compared with model group, and the effect of HEA on A1R was reversed by the administration of selective A1R antagonist DPCPX. These result demonstrated that HEA took the responsibility for the analgesia of gouty rats, and HEA may exert its antinociception by the activation of A1R, down-regulated A2AR and regulation of other pain-related genes.
The mechanisms of sclerotial formation from the hyphae of the medicinal fungus Polyporus umbellatus was investigated. Proteomics based on LC-MS was introduced into P. umbellatus. A total of 1 391 proteins were identified from sclerotia and hyphae at initial, developmental and mature phases based on data dependent acquisition (DDA) model. In total, 1 234 proteins were quantified from initial sclerotia and hyphae based on SWATH (Sequential Window Acquisition of all theoretical fragment ions) label-free model, and there were 378 proteins expressed differentially including 322 known and 56 unknown proteins. GO analytic results showed that these differential proteins were of varieties in molecular function and biological process during the sclerotial formation from the hyphae. Most of differential proteins were involved in catalytic and binding activities, and some were associated with response to stimulus, signal transduction, electron carrier, peroxidase activity, filamentous growth, cell wall biogenesis and so on. Further analysis results showed that types of stress (such as difference in temperature, hypoxia, etc.) induced the sclerotial formation of P. umbellatus from hypha, resulted in reactive oxygen species (ROS) generation and then developed into oxidative stress (OS). The signal transduced via MAPK pathway, and might regulate glycosylation of cell wall proteins, which were associated with cell polarities and filamentous hypha morphological changes. Besides, KEGG analysis indicated that proteins involved in synthesis and metabolism of secondary metabolites (such as terpenoids and polyketides) expressed differentially. It was the first time study on the proteome of P. umbellatus, which may be useful to deepen the knowledge on sclerotial formation.
Based on the tested indicators of polyphenol contents, total antioxidant capacity (T-AOC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging activities, and superoxide dismutase (SOD) activities, effects of different light and pH conditions on the antioxidant activities of medicinal fungus Trichaptum biforme during liquid cultivation were explored. The results demonstrated that T. biforme had antioxidant activities during submerged culture. Light treatment to a certain extent could enhance secretion capacity of secondary metabolites and antioxidant activities of the fungus. After being illuminated for 14d, the strain was shown to exert the highest capacities for secreting polyphenol and T-AOC, with the corresponding yields of 1.85mg/mL and 3.99U/mL on the 12th and 10th days. Higher DPPH radical scavenging efficiency and SOD activities were observed under alternation condition of dark for 1d and light for 1d, reaching their peaks of 87.44% and 0.63U/mL on the 2nd day. Effects of different pH conditions on the antioxidant activities of T. biforme during liquid cultivation were greater. When the pH was 9.0, the fungus exhibited better capacities of secreting polyphenol, T-AOC, and SOD, and performed remarkable scavenging activities against DPPH radicals, with respective values of 2.92mg/mL, 5.22U/mL, 0.70U/mL, and 95.07% on the 2nd, 10th, 2nd, and 2nd days. T. biforme showed the highest antioxidant activities at pH 9.0, and secondly by pH 3.0, 5.0, and 7.0, suggesting that relatively alkali or acidic conditions could stimulate the medicinal fungus T. biforme to secret more secondary metabolites to resist the oxidative stress from microenvironment.
Thirty five Polyporus umbellatus sclerotium samples were collected from 12 provinces of China. A HPLC method was developed for simultaneous quantitative determination of five sterone compounds in the samples. HPLC fingerprint was used to analyze the samples, and the similarity of fingerprint was calculated by the similarity evaluation system for chromatographic fingerprint of Chinese traditional medicine. Quantitative analysis showed that a total of 28 samples could obtain content determination results, and polyporusterone A and B accounted for more than 70% of the total sterone compounds in 25 of them. Correlation analysis showed a great significant positive correlation between the content of polyporusterone A and B (r=0.955, P<0.01). The samples from Shaanxi Province had the highest levels of average total sterone content and polyporusterone A and B relative content, being 182.70μg/g (C.V=82.4%) and 92.3% (C.V=3.1%) respectively. The similarity between the fingerprints of the 35 samples was 0.412-0.943. A total of eight common peaks could be found and three of them could be identified. The similarity between the fingerprints of the 11 samples from Shaanxi Province was 0.812-0.989. A total of 17 common peaks could be found and nine of them could be identified. The results suggested that polyporusterone A and B were the main sterone components in P. umbellatus sclerotia, and played an important role in the quality control of medicinal materials. It was also proved that the quality of P. umbellatus sclerotia from Shaanxi Province was good and stable.
As a valuable medicinal fungus, Sanghuangporus sanghuang has great potentials for various applications. Based on the tested indicators of mycelial biomass, polyphenol content, flavonoid content, AA content, T-AOC, RAHFR, superoxide radical scavenging ability, DPPH radical scavenging ability, ABTS radical scavenging ability, FRAP, and ferrous ion chelating activity, the antioxidant activities of S. sanghuang were evaluated during liquid cultivation. The results showed that the mycelial biomass increased dramatically in two to eight days, reaching its maximum at the 10th day. During liquid cultivation, the increased peaks of AA content and T-AOC were observed, and the upward trends of polyphenol content, flavonoid content, and FRAP were found, suggesting that antioxidant capacity of the fungus was dependent on mycelial growth, secondary metabolites secretion, and reducing power. Additionally, the fungus exhibited remarkable scavenging activities against hydroxyl free radicals, superoxide radicals, DPPH radicals, and ABTS radicals, with respective values of 73.06U/mL, 46.78%, 86.47%, and 94.16% on the 12th, 10th, 2nd, and 14th days. Higher ferrous ion chelating activity also indicated that S. sanghuang could activate its antioxidant system by blocking the free radical chain reaction, in order to protect itself from oxidative stress. The results facilitate further studies, development, and utilization of the medicinal fungus S. sanghuang.
Medicinal fungus Wolfiporia cocos sclerotia from different areas of Yunnan were identified by near infrared spectroscopy (NIR). The spectrum information was stepwise screened by spectrum standard deviation (SSD) and Monte Carlo uninformative variables elimination (MC-UVE) methods. The medulla and cortex of sclerotia were separated into the training set and validation set by K-S algorithm. Combined with partial least square discrimination analysis (PLS-DA), the classification models of medulla and cortex of the sclerotia from different producing areas were built. Furthermore, the Fisher equations were established. Through principal component mahalanobis distance (PCA-MD) analysis, the near infrared spectra of medulla and cortex showed significant difference in the space of principal component scores. It indicated that medulla and cortex should be separated when identification model of the sclerotia from different origins was built. As the optimal number of principal component was five, the classification models of medulla and cortex were built by 886 variables (7 501.74-4 088.35cm-1), which were screened by SSD method. The values of R2, RMSECV and RMSEP were 0.986, 0.988; 0.320, 0.283; 0.425, 0.395, respectively. Based on MC-UVE method, 34 variables of medulla and 22 variables of cortex were selected and the classification models were built. The values of R2, RMSECV and RMSEP were 0.993, 0.991; 0.224, 0.255; 0.298, 0.355, respectively. The models built by MC-UVE in combination with PLS-DA method effectively reduced the redundant information. The values of R2 were increased, and RMSECV and RMSEP were decreased, and the prediction accuracy of medulla and cortex were increased from 85.71% and 83.33% to 100%, respectively. Based on stepwise discriminant analysis, six variables of medulla and four variables of cortex were selected and Fisher equations were built. The returned validation accuracy was larger than 85.7%. The cross validation accuracy was larger than 66.7%. The results indicated the Fisher equations could identify Wolfiporia cocos sclerotia from different origin areas effectively.
