Cicadapeptins I and II: new Aib-containing peptides from the entomopathogenic fungus Cordyceps heteropoda

Bioactive compounds from Cordyceps and their therapeutic potential

The Clavicipitaceae family's largest and most diverse genus is Cordyceps. They are most abundant and diverse in humid temperate and tropical forests and have a wide distribution in: Europe, North America, and East and Southeast Asian countries, particularly: Bhutan, China, Japan, Nepal, Korea, Thailand, Vietnam, Tibet, and the Himalayan region of India, and Sikkim. It is a well-known parasitic fungus that feeds on insects and other arthropods belonging to 10 different orders. Over 200 bioactive metabolites, that include: nucleotides and nucleosides, polysaccharides, proteins, polypeptides, amino acids, sterols, and fatty acids, among others have been extracted from Cordyceps spp. demonstrating the phytochemical richness of this genus. These components have been associated with a variety of pharmacological effects, including: anti-microbial, anti-apoptotic, anti-cancer, anti-inflammatory, antioxidant, and immunomodulatory activities. In this paper, the bioactivity of various classes of metabolites produced by Cordyceps spp., and their therapeutic properties have been reviewed in an attempt to update the existing literature. Furthermore, one of its nucleoside and a key bioactive compound, cordycepin has been critically elaborated with regard to its biosynthesis pathway and the recently proposed protector-protégé mechanism as well as various biological and pharmacological effects, such as: suppression of purine and nucleic acid biosynthesis, induction of apoptosis, and cell cycle regulation with their mechanism of action. This review provides current knowledge on the bioactive potential of Cordyceps spp.

New species and new combinations in the genus Paraisaria (Hypocreales, Ophiocordycipitaceae) from the U.S.A., supported by polyphasic analysis

Molecular phylogenetic and chemical analyses, and morphological characterization of collections of North American Paraisaria specimens support the description of two new species and two new combinations for known species. P.cascadensissp. nov. is a pathogen of Cyphoderris (Orthoptera) from the Pacific Northwest USA and P.pseudoheteropodasp. nov. is a pathogen of cicadae (Hemiptera) from the Southeast USA. New combinations are made for Ophiocordycepsinsignis and O.monticola based on morphological, ecological, and chemical study. A new cyclopeptide family proved indispensable in providing chemotaxonomic markers for resolving species in degraded herbarium specimens for which DNA sequencing is intractable. This approach enabled the critical linkage of a 142-year-old type specimen to a phylogenetic clade. The diversity of Paraisaria in North America and the utility of chemotaxonomy for the genus are discussed.

Cordyceps spp.: A Review on Its Immune-Stimulatory and Other Biological Potentials

In recent decades, interest in the Cordyceps genus has amplified due to its immunostimulatory potential. Cordyceps species, its extracts, and bioactive constituents have been related with cytokine production such as interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12, and tumor necrosis factor (TNF)-α, phagocytosis stimulation of immune cells, nitric oxide production by increasing inducible nitric oxide synthase activity, and stimulation of inflammatory response via mitogen-activated protein kinase pathway. Other pharmacological activities like antioxidant, anti-cancer, antihyperlipidemic, anti-diabetic, anti-fatigue, anti-aging, hypocholesterolemic, hypotensive, vasorelaxation, anti-depressant, aphrodisiac, and kidney protection, has been reported in pre-clinical studies. These biological activities are correlated with the bioactive compounds present in Cordyceps including nucleosides, sterols, flavonoids, cyclic peptides, phenolic, bioxanthracenes, polyketides, and alkaloids, being the cyclic peptides compounds the most studied. An organized review of the existing literature was executed by surveying several databanks like PubMed, Scopus, etc. using keywords like Cordyceps, cordycepin, immune system, immunostimulation, immunomodulatory, pharmacology, anti-cancer, anti-viral, clinical trials, ethnomedicine, pharmacology, phytochemical analysis, and different species names. This review collects and analyzes state-of-the-art about the properties of Cordyceps species along with ethnopharmacological properties, application in food, chemical compounds, extraction of bioactive compounds, and various pharmacological properties with a special focus on the stimulatory properties of immunity.

Three Novel Entomopathogenic Fungi From China and Thailand

Entomopathogenic fungi are ubiquitous in tropical rainforests and feature a high level of diversity. This group of fungi not only has important ecological value but also medicinal value. Nevertheless, they are often ignored, and many unknown species have yet to be discovered and described. The present study aims to contribute to the taxonomical and phylogenetic understanding of the genus Paraisaria by describing three new species collected from Guizhou and Yunnan Provinces in China and Krabi Province in Thailand. The three novel species named Paraisaria alba, P. arcta, and P. rosea share similar morphologies as those in the genus Paraisaria, containing solitary, simple, fleshy stroma, completely immersed perithecia and cylindrical asci with thickened caps and filiform ascospores that often disarticulate at maturity. Phylogenetic analyses of combined LSU, SSU, TEF1-α, RPB1, RPB2, and ITS sequence data confirm their placement in the genus Paraisaria. In this study, the three entomopathogenic taxa are comprehensively described with color photographs and phylogenetic analyses. A synopsis table and a key to all treated species of Paraisaria are also included.

Sphaerostilbellins, New Antimicrobial Aminolipopeptide Peptaibiotics from Sphaerostilbella toxica

Sphaerostilbella toxica is a mycoparasitic fungus that can be found parasitizing wood-decay basidiomycetes in the southern USA. Organic solvent extracts of fermented strains of S. toxica exhibited potent antimicrobial activity, including potent growth inhibition of human pathogenic yeasts Candida albicans and Cryptococcus neoformans, the respiratory pathogenic fungus Aspergillus fumigatus, and the Gram-positive bacterium Staphylococcus aureus. Bioassay-guided separations led to the purification and structure elucidation of new peptaibiotics designated as sphaerostilbellins A and B. Their structures were established mainly by analysis of NMR and HRMS data, verification of amino acid composition by Marfey's method, and by comparison with published data of known compounds. They incorporate intriguing structural features, including an N-terminal 2-methyl-3-oxo-tetradecanoyl (MOTDA) residue and a C-terminal putrescine residue. The minimal inhibitory concentrations for sphaerostilbellins A and B were measured as 2 μM each for C. neoformans, 1 μM each for A. fumigatus, and 4 and 2 μM, respectively, for C. albicans. Murine macrophage cells were unaffected at these concentrations.

Diversity of Linear Non-Ribosomal Peptide in Biocontrol Fungi

Biocontrol fungi (BFs) play a key role in regulation of pest populations. BFs produce multiple non-ribosomal peptides (NRPs) and other secondary metabolites that interact with pests, plants and microorganisms. NRPs-including linear and cyclic peptides (L-NRPs and C-NRPs)-are small peptides frequently containing special amino acids and other organic acids. They are biosynthesized in fungi through non-ribosomal peptide synthases (NRPSs). Compared with C-NRPs, L-NRPs have simpler structures, with only a linear chain and biosynthesis without cyclization. BFs mainly include entomopathogenic and mycoparasitic fungi, that are used to control insect pests and phytopathogens in fields, respectively. NRPs play an important role of in the interactions of BFs with insects or phytopathogens. On the other hand, the residues of NRPs may contaminate food through BFs activities in the environment. In recent decades, C-NRPs in BFs have been thoroughly reviewed. However, L-NRPs are rarely investigated. In order to better understand the species and potential problems of L-NRPs in BFs, this review lists the L-NRPs from entomopathogenic and mycoparasitic fungi, summarizes their sources, structures, activities and biosynthesis, and details risks and utilization prospects.

Fungi-derived lipopeptide antibiotics developed since 2000

Lipopeptide antibiotics have linear or cyclic structures with one or more hydrocarbon tails linked to the N-terminus of a short oligopeptide that may be chemically modified and/or contain unusual amino acid residues in their structures. They possess huge potential as pharmaceutical drugs and biocontrol agents, and ˜30 representative genera of fungi are known to produce them. Some chemically synthesised derivatives have already been developed into commercial products or subjected to clinical trials, including cilofungin, caspofungin, micafungin, anidulafungin, rezafungin, emodepside, fusafungine and destruxins. This review summarizes 200 fungi-derived compounds reported since 2000, including 95 cyclic depsipeptides, 67 peptaibiotics (including 35 peptaibols, eight lipoaminopeptides, and five lipopeptaibols), and 38 non-depsipeptide and non-peptaibiotic lipopeptides. Their sources, structural sequences, antibiotic activities (e.g. antibacterial, antifungal, antiviral, antimycobacterial, antimycoplasmal, antimalarial, antileishmanial, insecticidal, antitrypanosomal and nematicidal), structure-activity relationships, mechanisms of action, and specific relevance are discussed. These compounds have attracted considerable interest within the pharmaceutical and agrochemical industries.

Chromosome level assembly and secondary metabolite potential of the parasitic fungus Cordyceps militaris

Background

Cordyceps militaris is an insect pathogenic fungus that is prized for its use in traditional medicine. This and other entomopathogenic fungi are understudied sources for the discovery of new bioactive molecules. In this study, PacBio SMRT long read sequencing technology was used to sequence the genome of C. militaris with a focus on the genetic potential for secondary metabolite production in the genome assembly of this fungus.

Results

This is first chromosome level assembly of a species in the Cordyceps genera. In this seven chromosome assembly of 33.6 Mba there were 9371 genes identified. Cordyceps militaris was determined to have the MAT 1-1-1 and MAT 1-1-2 mating type genes. Secondary metabolite analysis revealed the potential for at least 36 distinct metabolites from a variety of classes. Three of these gene clusters had homology with clusters producing desmethylbassianin, equisetin and emericellamide that had been studied in other fungi.

Conclusion

Our assembly and analysis has revealed that C. militaris has a wealth of gene clusters for secondary metabolite production distributed among seven chromosomes. The identification of these gene clusters will facilitate the future study and identification of the secondary metabolites produced by this entomopathogenic fungus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-4307-0) contains supplementary material, which is available to authorized users.

Risks of Mycotoxins from Mycoinsecticides to Humans

There are more than thirty mycotoxins produced by fungal entomopathogens. Totally, they belong to two classes, NRP and PK mycotoxins. Most of mycotoxins have not been paid sufficient attention yet. Generally, mycotoxins do not exist in mycoinsecticide and might not be released to environments unless entomogenous fungus proliferates and produces mycotoxins in host insects or probably in plants. Some mycotoxins, destruxins as an example, are decomposed in host insects before they, with the insect's cadavers together, are released to environments. Many species of fungal entomopathogens have the endophytic characteristics. But we do not know if fungal entomopathogens produce mycotoxins in plants and release them to environments. On the contrary, the same mycotoxins produced by phytopathogens such as Fusarium spp. and Aspergillus spp. have been paid enough concerns. In conclusion, mycotoxins from mycoinsecticides have limited ways to enter environments. The risks of mycotoxins from mycoinsecticides contaminating foods are controllable.

Toward a Cancer Drug of Fungal Origin

Although fungi produce highly structurally diverse metabolites, many of which have served as excellent sources of pharmaceuticals, no fungi-derived agent has been approved as a cancer drug so far. This is despite a tremendous amount of research being aimed at the identification of fungal metabolites with promising anticancer activities. This review discusses the results of clinical testing of fungal metabolites and their synthetic derivatives, with the goal to evaluate how far we are from an approved cancer drug of fungal origin. Also, because in vivo studies in animal models are predictive of the efficacy and toxicity of a given compound in a clinical situation, literature describing animal cancer testing of compounds of fungal origin is reviewed as well. Agents showing the potential to advance to clinical trials are also identified. Finally, the technological challenges involved in the exploitation of fungal biodiversity and procurement of sufficient quantities of clinical candidates are discussed, and potential solutions that could be pursued by researchers are highlighted.

Pharmacological and therapeutic potential of Cordyceps with special reference to Cordycepin

An entomopathogenic fungus, Cordyceps sp. has been known to have numerous pharmacological and therapeutic implications, especially, in terms of human health making it a suitable candidate for ethno-pharmacological use. Main constituent of the extract derived from this fungus comprises a novel bio-metabolite called as Cordycepin (3′deoxyadenosine) which has a very potent anti-cancer, anti-oxidant and anti-inflammatory activities. The current review discusses about the broad spectrum potential of Cordycepin including biological and pharmacological actions in immunological, hepatic, renal, cardiovascular systems as well as an anti-cancer agent. The article also reviews the current efforts to delineate the mechanism of action of Cordycepin in various bio-molecular processes. The study will certainly draw the attention of scientific community to improve the bioactivity and production of Cordycepin for its commercial use in pharmacological and medical fields.

The genus Cordyceps: a chemical and pharmacological review

Objectives

Natural remedies are becoming increasingly popular and important in the public and scientific communities. Historically, natural remedies have been shown to present interesting biological and pharmacological activity and are used as chemotherapeutic agents. For centuries Cordyceps, which is a genus of more than 400 species in the family Clavicipitaceae, has been used in traditional Chinese medicine. This study highlights the chemistry and pharmacology of Cordyceps, especially Cordyceps sinensis (Berk.) Sacc. and C. militaris (Fr.) L. Information was obtained from Google Scholar and the journal databases PubMed and Scopus.

Key findings

Many bioactive components of Cordyceps have been extracted, such as cordycepin, cordycepic acid, ergosterol, polysaccharides, nucleosides and peptides. Studies show that Cordyceps and its active principles possess a wide range of pharmacological actions, such as anti-inflammatory, antioxidant, antitumour, antihyperglycaemic, antiapoptosis, immunomodulatory, nephroprotective, and hepatoprotective.

Summary

More research is required to discover the full extent of the activity of Cordyceps.

Cultural Characteristics of Ophiocordyceps heteropoda Collected from Korea

Isolates of Ophiocordyceps heteropoda (Kobayasi) collected from Mt. Halla on Jeju-do, Korea were tested for mycelial growth on different agar media and in the presence of different carbon and nitrogen sources. Similarly, isolates were also incubated at different temperatures as well as under continuous light and dark conditions. Growth was better on Hamada agar, basal medium, and malt-yeast agar, but poor on Czapek-Dox agar. Different carbon sources such as dextrin, saccharose, starch, lactose, maltose, fructose, and dextrose resulted in better growth. Complex organic nitrogen sources such as yeast extract and peptone revealed the most effective growth. Mycelial growth was best at 25℃. The growth rate was faster in the dark than the light, but mycelial density was less compact in the dark.

N-containing compounds of macromycetes

This review surveys the chemical, biological, and mycological literature dealing with the isolation, structural elucidation, biological activities, and synthesis of nitrogen-containing compounds from the fruiting bodies or the culture broths of macromycetes.

Medicinal uses of the mushroom Cordyceps militaris: current state and prospects

Cordyceps militaris is a potential harbour of bio-metabolites for herbal drugs and evidences are available about its applications for revitalization of various systems of the body from ancient times. Amongst all the species, C. militaris is considered as the oldest source of some useful chemical constituents. Besides their popular applications for tonic medicine by the all stairs of the community, the constituents of C. militaris are now used extensively in modern systems of medicine. The current survey records the mysterious potentials of C. militaris are boosting up the present herbal treatments, as well as gearing up the green pharmacy revolution, in order to create a friendly environment with reasonable safety. Evidence showed that the active principles of C. militaris are beneficial to act as pro-sexual, anti-inflammatory, anti-oxidant/anti-aging, anti-tumour/anti-cancer/anti-leukemic, anti-proliferative, anti-metastatic, immunomodulatory, anti-microbial, anti-bacterial, anti-viral, anti-fungal, anti-protozoal, insecticidal, larvicidal, anti-fibrotic, steroidogenic, hypoglacaemic, hypolipidaemic, anti-angiogenetic, anti-diabetic, anti-HIV, anti-malarial, anti-fatigue, neuroprotective, liver-protective, reno-protective as well as pneumo-protective, let alone their other synergistic activities, which let it be marketable in the western countries as over-the-counter medicine. A number of culture techniques for this mushroom have been noticed, for example, storage/stock culture, pre-culture, popular/indigenous culture (spawn culture, husked rice culture and saw dust culture) and, special/laboratory culture (shaking culture, submerged culture, surface liquid culture and continuous/repeated batch culture). The prospects for herbal biotechnology regarding drug discovery using C. militaris delivering what it has promised are high, as the technology is now extremely more powerful than before. This study chiefly highlights the medicinal uses of the mushroom C. militaris including its culture techniques, also aiming to draw sufficient attention of the researchers to the frontier research needs in this context.

New fungal pathogens of the red ant, Myrmica rubra, from the UK and implications for ant invasions in the USA

The red ant, Myrmica rubra, is an increasingly invasive pest species in north-eastern USA, where it is known as the European fire ant. During surveys for natural enemies in part of its native range in the UK, three previously unreported fungal pathogens developed on ants when incubated in the laboratory. These are described and illustrated: Paraisaria myrmicarum sp. nov., Hirsutella stilbelliformis var. myrmicarum var. nov., and Hirsutella subramanianii var. myrmicarum var. nov. Based on analyses of the protein coding region EF-1α and LSU rDNA, all three described taxa are shown to be affiliated with the hypocrealean family Ophiocordycipitaceae. The implications for the management of M. rubra in its exotic North American range using classical biological control are discussed.

Pharmacological actions of Cordyceps, a prized folk medicine

Cordyceps species, including C. sinensis, C. militaris, C. pruinosa and C. ophioglossoides, are prized traditional medicinal materials. The aim of this article is to review the chemical constituents and pharmacological actions of Cordyceps species. The chemical constituents include cordycepin (3′-deoxyadenosine) and its derivatives, ergosterol, polysaccharides, a glycoprotein and peptides containing α-aminoisobutyric acid. They include anti-tumour, anti-metastatic, immunomodulatory, antioxidant, anti-inflammatory, insecticidal, antimicrobial, hypolipidaemic, hypoglycaemic, anti-ageing, neuroprotective and renoprotective effects. Polysaccharide accounts for the anti-inflammatory, antioxidant, anti-tumour, anti-metastatic, immunomodulatory, hypoglycaemic, steroidogenic and hypolipidaemic effects. Cordycepin contributes to the anti-tumour, insecticidal and antibacterial activity. Ergosterol exhibits anti-tumour and immunomodulatory activity. A DNase has been characterized.

An antimycobacterial cyclodepsipeptide from the entomopathogenic fungus Ophiocordyceps communis BCC 16475

A novel cyclodepsipeptide, cordycommunin (1), and two dihydroisocoumarins (2 and 3) were isolated from the insect pathogenic fungus Ophiocordyceps communis BCC 16475. The absolute configurations of the amino acid residues of 1 were addressed by application of Marfey's method. Cordycommunin (1) showed growth inhibition of Mycobacterium tuberculosis H37Ra with an MIC value of 15 microM. This compound also exhibited weak cytotoxicity to KB cells with an IC50 of 45 microM, while it was inactive against BC, NCI-H187, and Vero cell lines at a concentration of 88 microM (50 microg/mL).

Aib and iva in the biosphere: neither rare nor necessarily extraterrestrial

Fourty-nine species and strains of filamentous fungi of the genera Acremonium, Bionectria, Clonostachys, Emericellopsis, Hypocrea/Trichoderma, Lecythophora, Monocillium, Nectriopsis, Niesslia, Tolypocladium, and Wardomyces, deposited with the culture collection of the Centraalbureau voor Schimmelcultures (CBS) in Utrecht, The Netherlands, were grown on nutrient agar plates. Organic extracts of mycelia were analyzed after acidic total hydrolysis and derivatization by GC/SIM-MS on Chirasil-L-Val for the presence of Aib (=alpha-aminoisobutyric acid, 2-methylalanine) and DL-Iva (=isovaline, 2-ethylalanine). In 37 of the hydrolysates, Aib was detected, and in several of them D-Iva or mixtures of D- and L-Iva. Non-proteinogenic Aib, in particular, is a highly specific marker for a distinctive group of fungal polypeptides named peptaibols or, comprehensively, peptaibiotics, i.e., peptides containing Aib and displaying (anti)biotic activities. The biotic synthesis of these amino acids by filamentous fungi contradicts the still widespread belief that alpha,alpha-dialkyl-alpha-amino acids do not or rarely occur in the biosphere and, if detected, are of extraterrestrial origin. The abundant production of peptaibiotics by cosmopolitan species of microfungi has also to be considered in the discussion on the occurrence of Aib and Iva in ancient and recent sediments. The detection of trace amounts of Aib in ice samples of Antarctica that are devoid of meteorites might also be related to the presence of Aib-producing microorganisms, being either indigenous psychrophiles, or being transported and localized by mechanisms related to bioaerosols and cryoconites. The presence of microfungi being capable of producing alpha,alpha-dialkyl alpha-amino acids in terrestrial samples, and possible contamination of extraterrestrial materials are pointed out to be of relevance for the reliable interpretation of cosmogeochemical data.

Secondary metabolites from higher fungi: discovery, bioactivity, and bioproduction

Medicinal higher fungi such as Cordyceps sinensis and Ganoderma lucidum have been used as an alternative medicine remedy to promote health and longevity for people in China and other regions of the world since ancient times. Nowadays there is an increasing public interest in the secondary metabolites of those higher fungi for discovering new drugs or lead compounds. Current research in drug discovery from medicinal higher fungi involves a multifaceted approach combining mycological, biochemical, pharmacological, metabolic, biosynthetic and molecular techniques. In recent years, many new secondary metabolites from higher fungi have been isolated and are more likely to provide lead compounds for new drug discovery, which may include chemopreventive agents possessing the bioactivity of immunomodulatory, anticancer, etc. However, numerous challenges of secondary metabolites from higher fungi are encountered including bioseparation, identification, biosynthetic metabolism, and screening model issues, etc. Commercial production of secondary metabolites from medicinal mushrooms is still limited mainly due to less information about secondary metabolism and its regulation. Strategies for enhancing secondary metabolite production by medicinal mushroom fermentation include two-stage cultivation combining liquid fermentation and static culture, two-stage dissolved oxygen control, etc. Purification of bioactive secondary metabolites, such as ganoderic acids from G. lucidum, is also very important to pharmacological study and future pharmaceutical application. This review outlines typical examples of the discovery, bioactivity, and bioproduction of secondary metabolites of higher fungi origin.

Cordyceps: a traditional Chinese medicine and another fungal therapeutic biofactory?

Traditional Chinese medicines (TCM) are growing in popularity. However, are they effective? Cordyceps is not studied as systematically for bioactivity as another TCM, Ganoderma. Cordyceps is fascinating per se, especially because of the pathogenic lifestyle on Lepidopteron insects. The combination of the fungus and dead insect has been used as a TCM for centuries. However, the natural fungus has been harvested to the extent that it is an endangered species. The effectiveness has been attributed to the Chinese philosophical concept of Yin and Yang and can this be compatible with scientific philosophy? A vast literature exists, some of which is scientific, although others are popular myth, and even hype. Cordyceps sinensis is the most explored species followed by Cordyceps militaris. However, taxonomic concepts were confused until a recent revision, with undefined material being used that cannot be verified. Holomorphism is relevant and contamination might account for some of the activity. The role of the insect has been ignored. Some of the analytical methodologies are poor. Data on the "old" compound cordycepin are still being published: ergosterol and related compounds are reported despite being universal to fungi. There is too much work on crude extracts rather than pure compounds with water and methanol solvents being over-represented in this respect (although methanol is an effective solvent). Excessive speculation exists as to the curative properties. However, there are some excellent pharmacological data and relating to apoptosis. For example, some preparations are active against cancers or diabetes which should be fully investigated. Polysaccharides and secondary metabolites are of particular interest. The use of genuine anamorphic forms in bioreactors is encouraged.

New Sequences, Constituents, and Producers of Peptaibiotics: An Updated Review

To date, 18 genera of imperfect and ascomycetous fungi have been recognized to produce ca. 700 individual sequences of peptaibiotics. These are linear polypeptide antibiotics which i) have a molecular weight between 500 and 2,200 Dalton, thus containing 5-21 residues; ii) show a high content of alpha-aminoisobutyric acid; iii) are characterized by the presence of other nonproteinogenic amino acids and/or lipoamino acids; iv) possess an acylated N-terminus, and v) have a C-terminal residue that, in most of them, consists of a free or acetylated amide-bonded 1,2-amino alcohol, but might also be an amine, amide, free amino acid, 2,5-dioxopiperazine, or sugar alcohol. From April 2003 until present, ca. 300 new individual sequences of peptaibiotics have been published in the literature, but most of them have not yet been included in databases. To summarize these new sequences and novel constituents, as well as to introduce fungal species hitherto unknown as producers of peptaibiotics, the relevant literature is reviewed. Furthermore, ecophysiological and taxonomic aspects of the producing fungi are discussed.

Hypoglycemic activity of the fungi Cordyceps militaris, Cordyceps sinensis, Tricholoma mongolicum, and Omphalia lapidescens in streptozotocin-induced diabetic rats

Crude extracts were prepared from fruiting bodies and mycelia of the medicinal fungus Cordyceps militaris, and a polysaccharide-enriched fraction was obtained after extraction with hot water and ethanol precipitation. Polysaccharide-enriched fractions were similarly prepared from Cordyceps sinensis, Omphalia lapidescens, and Tricholoma mongolicum. The various aforementioned preparations were orally administered into different groups of adult rats 24 h before an intraperitoneal injection of streptozotocin (40 mg/kg body weight), and subsequently daily for another 4 days. The dosage used was 10 mg/kg body weight for polysaccharide-enriched preparations and 100 mg/kg body weight for crude extracts. Control rats received distilled water instead of crude extract or polysaccharide-enriched preparation. It was found in the control rats that plasma glucose level rose from about 90 mg/dl before streptozotocin injection to levels that were maintained at about 300 mg/dl postinjection. All preparations produced hypoglycemic effects. C. militaris polysaccharide-enriched fraction displayed a more prominent effect than that of C. sinensis polysaccharide-enriched fraction which in turn was more potent than that of O. lapidescens and T. mongolicum polysaccharide-enriched fractions. The hypoglycemic effect of C. militaris polysaccharide-enriched fraction was dose-dependent.