Marmorin, a new ribosome inactivating protein with antiproliferative and HIV-1 reverse transcriptase inhibitory activities from the mushroom Hypsizigus marmoreus

Medicinal Fungi with Antiviral Effect

Pandemics from various viruses make natural organisms face challenges over and over again. Therefore, new antiviral drugs urgently need to be found to solve this problem. However, drug research and development is a very difficult task, and finding new antiviral compounds is desirable. A range of medicinal fungi such as Ganoderma lucidum and Cordyceps sinensis are widely used all over the world, and they can enhance human immunity and direct anti-virus activities and other aspects to play an antiviral role. Medicinal fungi are used as foods or as food supplements. In this review, the species of medicinal fungi with antiviral activity in recent decades and the mechanism of antiviral components were reviewed from the perspectives of human, animal, and plant viruses to provide a comprehensive theory based on better clinical utilization of medicinal fungi as antiviral agents.

Ribotoxic Proteins, Known as Inhibitors of Protein Synthesis, from Mushrooms and Other Fungi According to Endo's Fragment Detection

rRNA N-glycosylases (EC 3.2.2.22) remove a specific adenine (A₄₃₂₄, rat 28S rRNA) in the sarcin ricin loop (SRL) involved into ribosome interaction with elongation factors, causing the inhibition of translation, for which they are known as plant 'ribosome inactivating proteins' (RIPs). However, protein synthesis inactivation could be the result of other enzymes, which often have rRNA as the target. In this scenario, Endo's assay is the most used method to detect the enzymes that are able to hydrolyze a phosphodiester bond or cleave a single N-glycosidic bond (rRNA N-glycosylases). Indeed, the detection of a diagnostic fragment from rRNA after enzymatic action, with or without acid aniline, allows one to discriminate between the N-glycosylases or hydrolases, which release the β-fragment after acid aniline treatment or α-fragment without acid aniline treatment, respectively. This assay is of great importance in the mushroom kingdom, considering the presence of enzymes that are able to hydrolyze phosphodiester bonds (e.g., ribonucleases, ribotoxins and ribotoxin-like proteins) or to remove a specific adenine (rRNA N-glycosylases). Thus, here we used the β-fragment experimentally detected by Endo's assay as a hallmark to revise the literature available on enzymes from mushrooms and other fungi, whose action consists of protein biosynthesis inhibition.

Lyophyllin, a Mushroom Protein from the Peptidase M35 Superfamily Is an RNA N-Glycosidase

Ribosome-inactivating proteins (RIPs) hydrolyze the N-glycosidic bond and depurinate a specific adenine residue (A-4324 in rat 28S ribosomal RNA, rRNA) in the conserved α-sarcin/ricin loop (α-SRL) of rRNA. In this study, we have purified and characterized lyophyllin, an unconventional RIP from Lyophyllum shimeji, an edible mushroom. The protein resembles peptidase M35 domain of peptidyl-Lys metalloendopeptidases. Nevertheless, protein either from the mushroom or in recombinant form possessed N-glycosidase and protein synthesis inhibitory activities. A homology model of lyophyllin was constructed. It was found that the zinc binding pocket of this protein resembles the catalytic cleft of a classical RIP, with key amino acids that interact with the adenine substrate in the appropriate positions. Mutational studies showed that E122 may play a role in stabilizing the positively charged oxocarbenium ion and H121 for protonating N-3 of adenine. The tyrosine residues Y137 and Y104 may be used for stacking the target adenine ring. This work first shows a protein in the peptidase M35 superfamily based on conserved domain search possessing N-glycosidase activity.

Narrative Review: Bioactive Potential of Various Mushrooms as the Treasure of Versatile Therapeutic Natural Product

Mushrooms have remained an eternal part of traditional cuisines due to their beneficial health potential and have long been recognized as a folk medicine for their broad spectrum of nutraceuticals, as well as therapeutic and prophylactic uses. Nowadays, they have been extensively investigated to explain the chemical nature and mechanisms of action of their biomedicine and nutraceuticals capacity. Mushrooms belong to the astounding dominion of Fungi and are known as a macrofungus. Significant health benefits of mushrooms, including antiviral, antibacterial, anti-parasitic, antifungal, wound healing, anticancer, immunomodulating, antioxidant, radical scavenging, detoxification, hepatoprotective cardiovascular, anti-hypercholesterolemia, and anti-diabetic effects, etc., have been reported around the globe and have attracted significant interests of its further exploration in commercial sectors. They can function as functional foods, help in the treatment and therapeutic interventions of sub-optimal health states, and prevent some consequences of life-threatening diseases. Mushrooms mainly contained low and high molecular weight polysaccharides, fatty acids, lectins, and glucans responsible for their therapeutic action. Due to the large varieties of mushrooms present, it becomes challenging to identify chemical components present in them and their beneficial action. This article highlights such therapeutic activities with their active ingredients for mushrooms.

Biomolecules of mushroom: a recipe of human wellness

The Indian system of medicine - Ayurveda says "When diet is wrong, medicine is of no use. When diet is correct, medicine is of no use". In this context, mushroom constitutes one of the major resources for nutraceuticals. Biomolecules of mushrooms have attracted the attention of researchers around the globe due to their proven healthy attributes. They have a plenitude of health-giving properties and these range from immunomodulatory, antiviral, antibacterial, antifungal, antioxidant, anti-inflammatory, antitumor, anticancer, anti-HIV, antidiabetic, anticholesterolic to antiarthritic activities.Mushrooms contain both primary and secondary metabolites. The primary metabolites provide energy while the secondary metabolite exhibits medicinal properties. Hence, the mushroom can be a recipe for human wellness and will play a significant role in fighting COVID-19 pandemics and other infectious diseases.The key findings suggested in this paper refer to the exploration of health and the healing traits of biomolecules of mushrooms. This article reviews the current status of the medicinal attributes of mushrooms and their biomolecules in different diseases such as cardiovascular, diabetes, reproductive diseases, cancer, and neurodegenerative diseases. The global malnutrition-related morbidity and mortality among children under five and lactating women presents a frightening picture and also a black spot on the human face. Malnutrition is responsible for more ill-health than any other cause. Mushrooms as a rich source of bioactive compounds can be claimed as "Best from the Waste" since they grow on the most abundant organic wastes of the Earth, the lignocellulosic substrate, and 'Best of the Rest' because they are excellent nutraceutical resources.

Natural Products with Inhibitory Activity against Human Immunodeficiency Virus Type 1

Infections caused by human immunodeficiency virus (HIV) are considered one of the main public health problems worldwide. Antiretroviral therapy (ART) is the current modality of treatment for HIV-1 infection. It comprises the combined use of several drugs and can decrease the viral load and increase the CD4+ T cell count in patients with HIV-1 infection, thereby proving to be an effective modality. This therapy significantly decreases the rate of morbidity and mortality owing to acquired immunodeficiency syndrome (AIDS) and prolongs and improves the quality of life of infected patients. However, nonadherence to ART may increase viral resistance to antiretroviral drugs and transmission of drug-resistant strains of HIV. Therefore, it is necessary to continue research for compounds with anti-HIV-1 activity, exhibiting a potential for the development of an alternative or complementary therapy to ART with low cost and fewer side effects. Natural products and their derivatives represent an excellent option owing to their therapeutic potential against HIV. Currently, the derivatives of natural products available as anti-HIV-1 agents include zidovudine, an arabinonucleoside derivative of the Caribbean marine sponge (Tectitethya crypta), which inhibits the reverse transcriptase of the virus. This was the first antiviral agent approved for treatment of HIV infection. Additionally, bevirimat (isolated from Syzygium claviflorum) and calanolide A (isolated from Calophyllum sp.) are inhibitors of viral maturation and reverse transcription process, respectively. In the present review, we aimed to describe the wide repertoire of natural compounds exhibiting anti-HIV-1 activity that can be considered for designing new therapeutic strategies to curb the HIV pandemic.

Lectins purified from medicinal and edible mushrooms: Insights into their antiviral activity against pathogenic viruses

For thousands of years, fungi have been a valuable and promising source of therapeutic agents for treatment of various diseases. Mushroom is a macrofungus which has been cultivated worldwide for its nutritional value and medicinal applications. Several bioactive molecules were extracted from mushroom such as polysaccharides, lectins and terpenoids. Lectins are carbohydrate-binding proteins with non-immunologic origin. Lectins were classified according to their structure, origin and sugar specificity. This protein has different binding specificity with surface glycan moiety which determines its activity and therapeutic applications. A wide range of medicinal activities such as antitumor, antiviral, antimicrobial, immunomodulatory and antidiabetic were reported from sugar-binding proteins. However, glycan-binding protein from mushroom is not well explored as antiviral agent. The discovery of novel antiviral agents is a public health emergency to overcome the current pandemic and be ready for the upcoming viral pandemics. The mechanism of action of lectin against viruses targets numerous steps in viral life cycle such as viral attachment, entry and replication. This review described the history, classification, purification techniques, structure-function relationship and different therapeutic applications of mushroom lectin. In addition, we focus on the antiviral activity, purification and physicochemical characteristics of some mushroom lectins.

Anti-HIV-1 reverse transcriptase property of some edible mushrooms in Asia

Human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS), which is a serious health threat worldwide. One of its core enzymes, reverse transcriptase (RT), is a target for HIV inhibition. A number of bioactive compounds have been successfully used for HIV treatment. However, HIV rapidly mutates, and long-term treatment can cause drug-resistant strains. Therefore, new inhibitors are required to overcome this problem. In this study, the aqueous, ethanolic and hexane crude extracts of 19 edible and medicinal mushrooms, which are widely grown and available commercially in Thailand, were screened against HIV-1 RT. The results showed that the water extracts of A. blazei and I. obliquus, the ethanol extracts of I. obliquus and P. igniarius and the hexane extract of I. obliquus exhibited strong anti-HIV-1 RT activity with IC₅₀ values of 1.92 ± 0.15, 4.39 ± 0.79, 6.17 ± 0.76 and 7.75 ± 246 µg/ml, respectively. These mushrooms have the potential for HIV treatment, and further study on identification of the bioactive compounds against HIV-1 RT should be performed.

Antiviral Activity of Ribosome-Inactivating Proteins

Ribosome-inactivating proteins (RIPs) are rRNA N-glycosylases from plants (EC 3.2.2.22) that inactivate ribosomes thus inhibiting protein synthesis. The antiviral properties of RIPs have been investigated for more than four decades. However, interest in these proteins is rising due to the emergence of infectious diseases caused by new viruses and the difficulty in treating viral infections. On the other hand, there is a growing need to control crop diseases without resorting to the use of phytosanitary products which are very harmful to the environment and in this respect, RIPs have been shown as a promising tool that can be used to obtain transgenic plants resistant to viruses. The way in which RIPs exert their antiviral effect continues to be the subject of intense research and several mechanisms of action have been proposed. The purpose of this review is to examine the research studies that deal with this matter, placing special emphasis on the most recent findings.

Anticancer potentiality and mode of action of low-carbohydrate proteins and peptides from mushrooms

Severe side effects of chemotherapy as well as drug resistance highlight the ongoing need to discover novel natural bioactive compounds with anticancer potentiality. Mushroom-derived proteins are among the naturally occurring compounds that have been the subject of a body of research on their potentiality in cancer therapy. The greatest attention in relevant review articles has been paid to well-known mushroom-derived glycoproteins such as lectins and protein-bound polysaccharide complexes such as polysaccharide-K (PSK) or krestin and polysaccharopeptide (PSP), which contain substantial amounts of carbohydrates (50-90%). These complex compounds exert their anticancer activity mainly by binding to cell membranes leading to extrinsic (death receptor) apoptosis or intrinsic (mitochondrial) apoptotic pathways. However, several other research studies have reported pure, well-characterized, proteins or peptides from mushrooms, which are carbohydrate-free or have very low amounts of carbohydrate. These proteins may fall into four categories including fungal immunomodulatory proteins, ubiquitin-like proteins, enzymes, and unclassified proteins. Well-defined chemical structure, elucidated full amino acid or N-terminal sequences, purity, and having some distinct and specific pathways compared to glycoproteins have made these low-carbohydrate proteins attractive for cancer research. The aim of this review was therefore to improve the current understanding of mushroom-derived low-carbohydrate proteins and to consolidate the existing knowledge of the most promising mushroom species from which low-carbohydrate proteins have been derived, characterized, and examined for their anticancer activity. In addition, molecular targets and mechanisms of action of these proteins have been discussed. Key points • Mushroom-derived low-carbohydrate proteins lack or have low carbohydrate. • Low-carbohydrate proteins show potent anticancer activities in vitro and in vivo. • There are specific pathways for low-carbohydrate proteins to inhibit cancer cells.

Mushroom extracts and compounds with suppressive action on breast cancer: evidence from studies using cultured cancer cells, tumor-bearing animals, and clinical trials

This article reviews mushrooms with anti-breast cancer activity. The mushrooms covered which are better known include the following: button mushroom Agaricus bisporus, Brazilian mushroom Agaricus blazei, Amauroderma rugosum, stout camphor fungus Antrodia camphorata, Jew's ear (black) fungus or black wood ear fungus Auricularia auricula-judae, reishi mushroom or Lingzhi Ganoderma lucidum, Ganoderma sinense, maitake mushroom or sheep's head mushroom Grifola frondosa, lion's mane mushroom or monkey head mushroom Hericium erinaceum, brown beech mushroom Hypsizigus marmoreus, sulfur polypore mushroom Laetiporus sulphureus, Lentinula edodes (shiitake mushroom), Phellinus linteus (Japanese "meshimakobu," Chinese "song gen," Korean "sanghwang," American "black hoof mushroom"), abalone mushroom Pleurotus abalonus, king oyster mushroom Pleurotus eryngii, oyster mushroom Pleurotus ostreatus, tuckahoe or Fu Ling Poria cocos, and split gill mushroom Schizophyllum commune. Antineoplastic effectiveness in human clinical trials and mechanism of anticancer action have been reported for Antrodia camphorata, Cordyceps sinensis, Coriolus versicolor, Ganoderma lucidum, Grifola frondosa, and Lentinula edodes.

New ribosome-inactivating proteins and other proteins with protein synthesis-inhibiting activities

Ribosome-inactivating proteins (RIPs) consist of three varieties. Type 1 RIPs are single-chained and approximately 30-kDa in molecular weight. Type 2 RIPs are double-chained and composed of a type 1 RIP chain and a lectin chain. Type III RIPs, such as maize b-32 barley and JIP60 which are produced as single-domain proenzymes, possess an N-terminal domain corresponding to the A domain of RIPs and fused to a C-terminal domain. In addition to the aforementioned three types of RIPs originating from flowering plants, there are recently discovered proteins and peptides with ribosome-inactivating and protein synthesis inhibitory activities but which are endowed with characteristics such as molecular weights distinctive from those of the regular RIPs. These new/unusual RIPs discussed in the present review encompass metazoan RIPs from Anopheles and Culex mosquitos, antimicrobial peptides derived from RIP of the pokeweed Phytolacca dioica, maize RIP (a type III RIP derived from a precursor form), RIPs from the garden pea and the kelp. In addition, RIPs with a molecular weight smaller than those of regular type 1 RIPs are produced by plants in the Cucurbitaceae family including the bitter gourd, bottle gourd, sponge gourd, ridge gourd, wax gourd, hairy gourd, pumpkin, and Chinese cucumber. A small type II RIP from camphor tree (Cinnamomum camphora) seeds and a snake gourd type II RIP with its catalytic chain cleaved into two have been reported. RIPs produced from mushrooms including the golden needle mushroom, king tuber mushroom, straw mushroom, and puffball mushroom are also discussed in addition to a type II RIP from the mushroom Polyporus umbellatus. Bacterial (Spiroplasma) RIPs associated with the fruitfly, Shiga toxin, and Streptomyces coelicolor RIP are also dealt with. The aforementioned proteins display a diversity of molecular weights, amino acid sequences, and mechanisms of action. Some of them are endowed with exploitable antipathogenic activities.

Edible mushrooms as a novel protein source for functional foods

Fast demographic growth has led to increasing interest in low-cost alternative protein sources to meet population needs.

Antifungal Proteins with Antiproliferative Activity on Cancer Cells and HIV-1 Enzyme Inhibitory Activity from Medicinal Plants and Medicinal Fungi

A variety of fungi, plants, and their different tissues are used in Traditional Chinese Medicine to improve health, and some of them are recommended for dietary therapy. Many of these plants and fungi contain antifungal proteins and peptides which suppress spore germination and hyphal growth in phytopathogenic fungi. The aim of this article is to review antifungal proteins produced by medicinal plants and fungi used in Chinese medicine which also possess anticancer and human immunodeficiency virus-1 (HIV-1) enzyme inhibitory activities.

Genomic discovery of the hypsin gene and biosynthetic pathways for terpenoids in Hypsizygus marmoreus

Background

Hypsizygus marmoreus (Beech mushroom) is a popular ingredient in Asian cuisine. The medicinal effects of its bioactive compounds such as hypsin and hypsiziprenol have been reported, but the genetic basis or biosynthesis of these components is unknown.

Results

In this study, we sequenced a reference strain of H. marmoreus (Haemi 51,987–8). We evaluated various assembly strategies, and as a result the Allpaths and PBJelly produced the best assembly. The resulting genome was 42.7 Mbp in length and annotated with 16,627 gene models. A putative gene (Hypma_04324) encoding the antifungal and antiproliferative hypsin protein with 75% sequence identity with the previously known N-terminal sequence was identified. Carbohydrate active enzyme analysis displayed the typical feature of white-rot fungi where auxiliary activity and carbohydrate-binding modules were enriched. The genome annotation revealed four terpene synthase genes responsible for terpenoid biosynthesis. From the gene tree analysis, we identified that terpene synthase genes can be classified into six clades. Four terpene synthase genes of H. marmoreus belonged to four different groups that implies they may be involved in the synthesis of different structures of terpenes. A terpene synthase gene cluster was well-conserved in Agaricomycetes genomes, which contained known biosynthesis and regulatory genes.

Conclusions

Genome sequence analysis of this mushroom led to the discovery of the hypsin gene. Comparative genome analysis revealed the conserved gene cluster for terpenoid biosynthesis in the genome. These discoveries will further our understanding of the biosynthesis of medicinal bioactive molecules in this edible mushroom.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5159-y) contains supplementary material, which is available to authorized users.

Purification and characterization of a novel ubiquitin-like antitumour protein with hemagglutinating and deoxyribonuclease activities from the edible mushroom Ramaria botrytis

A novel ubiquitin-like antitumour protein (RBUP) was isolated from fruiting bodies of the edible mushroom Ramaria botrytis. The protein was isolated with a purification protocol involving ion exchange chromatography on DEAE-Sepharose fast flow and gel filtration on Sephadex G-75. SDS-PAGE, Native-PAGE and ultracentrifugation analysis disclosed that RBUP was a monomeric protein with a molecular weight of 18.5 kDa. ESI-MS/MS demonstrated that it shared 69% amino acid sequence similarity with Coprinellus congregates ubiquitin (gi|136667). The protein exhibiting strong anticancer activity towards A549 cells. Analysis by employing AO/EB staining and Annexin V-FITC/PI detection indicated that the cytotoxic effect of RBUP was mediated through induction of apoptosis. Furthermore, RBUP displayed hemagglutinating and deoxyribonuclease activities. A temperature of 40 °C and pH of 7.0 were required for optimal DNase activity. Therefore, it was estimated that RBUP exerted its antitumour effect by inducing apoptosis, and its hemagglutinating and DNase activities were also thought to participate in this effect. These results demonstrated that RBUP was a multifunctional protein with potential medicinal applications.

Isolation and Characterization of a Phaseolus vulgaris Trypsin Inhibitor with Antiproliferative Activity on Leukemia and Lymphoma Cells

A 17.5-kDa trypsin inhibitor was purified from Phaseolus vulgaris cv. “gold bean” with an isolation protocol including ion exchange chromatography on DEAE-cellulose (Diethylaminoethyl-cellulose), affinity chromatography on Affi-gel blue gel, ion exchange chromatography on SP-sepharose (Sulfopropyl-sepharose), and gel filtration by FPLC (Fast protein liquid chromatography) on Superdex 75. It dose-dependently inhibited trypsin with an IC₅₀ value of 0.4 μM, and this activity was reduced in the presence of dithiothreitol in a dose- and time-dependent manner, signifying the importance of the disulfide linkage to the activity. It inhibited [methyl-³H] thymidine incorporation by leukemia L1210 cells and lymphoma MBL2 cells with an IC₅₀ value of 2.3 μM and 2.5 μM, respectively. The inhibitor had no effect on fungal growth and the activities of various viral enzymes when tested up to 100 μM.

Fungal proteinaceous compounds with multiple biological activities

Fungi comprise organisms like molds, yeasts and mushrooms. They have been used as food or medicine for a long time. A large number of fungal proteins or peptides with diverse biological activities are considered as antibacterial, antifungal, antiviral and anticancer agents. They encompass proteases, ribosome inactivating proteins, defensins, hemolysins, lectins, laccases, ribonucleases, immunomodulatory proteins, and polysaccharopeptides. The target of the present review is to update the status of the various bioactivities of these fungal proteins and peptides and discuss their therapeutic potential.

Bitter melon: a panacea for inflammation and cancer

Nature is a rich source of medicinal plants and their products that are useful for treatment of various diseases and disorders. Momordica charantia, commonly known as bitter melon or bitter gourd, is one of such plants known for its biological activities used in traditional system of medicines. This plant is cultivated in all over the world, including tropical areas of Asia, Amazon, east Africa, and the Caribbean and used as a vegetable as well as folk medicine. All parts of the plant, including the fruit, are commonly consumed and cooked with different vegetables, stir-fried, stuffed or used in small quantities in soups or beans to give a slightly bitter flavor and taste. The plant is reported to possess anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, anti-bacterial, anti-obesity, and immunomodulatory activities. The plant extract inhibits cancer cell growth by inducing apoptosis, cell cycle arrest, autophagy and inhibiting cancer stem cells. The plant is rich in bioactive chemical constituents like cucurbitane type triterpenoids, triterpene glycosides, phenolic acids, flavonoids, essential oils, saponins, fatty acids, and proteins. Some of the isolated compounds (Kuguacin J, Karaviloside XI, Kuguaglycoside C, Momordicoside Q-U, Charantin, α-eleostearic acid) and proteins (α-Momorcharin, RNase MC2, MAP30) possess potent biological activity. In the present review, we are summarizing the anti-oxidant, anti-inflammatory, and anti-cancer activities of Momordica charantia along with a short account of important chemical constituents, providing a basis for establishing detail biological activities of the plant and developing novel drug molecules based on the active chemical constituents.

Proteins, peptides, polysaccharides, and nucleotides with inhibitory activity on human immunodeficiency virus and its enzymes

Human immunodeficiency virus (HIV), the causative agent of acquired immune deficiency syndrome, has claimed innumerable lives in the past. Many biomolecules which suppress HIV replication and also other biomolecules that inhibit enzymes essential to HIV replication have been reported. Proteins including a variety of milk proteins, ribosome-inactivating proteins, ribonucleases, antifungal proteins, and trypsin inhibitors; peptides comprising cathelicidins, defensins, synthetic peptides, and others; polysaccharides and polysaccharopeptides; nucleosides, nucleotides, and ribozymes, demonstrated anti-HIV activity. In many cases, the mechanism of anti-HIV action has been elucidated. Strategies have been devised to augment the anti-HIV potency of these compounds.

Biological activities of ribosome-inactivating proteins and their possible applications as antimicrobial, anticancer, and anti-pest agents and in neuroscience research

Ribosome-inactivating proteins (RIPs) are enzymes which depurinate ribosomal RNA (rRNA), thus impeding the process of translation resulting in inhibition of protein synthesis. They are produced by various organisms including plants, fungi and bacteria. RIPs from plants are linked to plant defense due to their antiviral, antifungal, antibacterial, and insecticidal activities in which they can be applied in agriculture to combat microbial pathogens and pests. Their anticancer, antiviral, embryotoxic, and abortifacient properties may find medicinal applications. Besides, conjugation of RIPs with antibodies or other carriers to form immunotoxins has been found useful to research in neuroscience and anticancer therapy.

Ribosome-inactivating and related proteins

Ribosome-inactivating proteins (RIPs) are toxins that act as N-glycosidases (EC 3.2.2.22). They are mainly produced by plants and classified as type 1 RIPs and type 2 RIPs. There are also RIPs and RIP related proteins that cannot be grouped into the classical type 1 and type 2 RIPs because of their different sizes, structures or functions. In addition, there is still not a uniform nomenclature or classification existing for RIPs. In this review, we give the current status of all known plant RIPs and we make a suggestion about how to unify those RIPs and RIP related proteins that cannot be classified as type 1 or type 2 RIPs.

Sequence comparison and phylogenetic analysis by the Maximum Likelihood method of ribosome-inactivating proteins from angiosperms

Ribosome-inactivating proteins (RIPs) from angiosperms are rRNA N-glycosidases that have been proposed as defence proteins against virus and fungi. They have been classified as type 1 RIPs, consisting of single-chain proteins, and type 2 RIPs, consisting of an A chain with RIP properties covalently linked to a B chain with lectin properties. In this work we have carried out a broad search of RIP sequence data banks from angiosperms in order to study their main structural characteristics and phylogenetic evolution. The comparison of the sequences revealed the presence, outside of the active site, of a novel structure that might be involved in the internal protein dynamics linked to enzyme catalysis. Also the B-chains presented another conserved structure that might function either supporting the beta-trefoil structure or in the communication between both sugar-binding sites. A systematic phylogenetic analysis of RIP sequences revealed that the most primitive type 1 RIPs were similar to that of the actual monocots (Poaceae and Asparagaceae). The primitive RIPs evolved to the dicot type 1 related RIPs (like those from Caryophyllales, Lamiales and Euphorbiales). The gene of a type 1 RIP related with the actual Euphorbiaceae type 1 RIPs fused with a double beta trefoil lectin gene similar to the actual Cucurbitaceae lectins to generate the type 2 RIPs and finally this gene underwent deletions rendering either type 1 RIPs (like those from Cucurbitaceae, Rosaceae and Iridaceae) or lectins without A chain (like those from Adoxaceae).

Efficient purification of antiproliferative polysaccharides from Hypsizigus marmoreus with radial flow chromatography

The increasing commercial significance of natural polysaccharides for use in medicinal products is stimulating the development of efficient and easy scale-up techniques for polysaccharide purification. In this research, the crude polysaccharides from submerged cultivation broth of Hypsizigus marmoreus were purified using radial flow chromatography (RFC), and the antiproliferative activity of the purified fractions was evaluated in vitro. DEAE Sepharose CL-6B was selected to be packed in the RFC column based on its good resolution, physical stability, and low cost. Compared with axial flow chromatography (AFC), an efficient chromatographic process with significantly less time and buffer consumption but yielding higher polysaccharide recovery and resolution was established in RFC, which could clearly purify the crude polysaccharides into different fractions. An acceptable linear scale-up effect of RFC from 100 to 500 mL was successfully achieved without loss of resolution and enhancement of time consumption. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in cell cultures indicated that the purified polysaccharide fractions possess moderate antiproliferative activities in three different human cancer cell lines, but have significantly lower cytotoxicity in normal human cell lines in vitro. Among the polysaccharide fractions, the main purified acidic fraction W-I could be considered as a novel potential antitumor agent candidate for several tumors, especially for human alveolar epithelial tumors. This research confirmed for the first time that RFC would be a new fast and efficient tool for purification of polysaccharides into different fractions, both at laboratory and commercial scales.

Characterisation and immunomodulating activities of exo-polysaccharides from submerged cultivation of Hypsizigus marmoreus

Exo-polysaccharides were purified and characterized from the fermentation broth of Hypsizigus marmoreus, a popular edible mushroom consumed in Asia. Among them, B-I-I and B-II-I exhibited potent complement fixating activity, meanwhile, B-N-I, B-I-I, B-II-I and B-II-II exhibited significant macrophage stimulating activity. Molecular weights of the four exo-polysaccharides were determined to be 6.3, 120, 150 and 11 kDa respectively. Molecular characterisation showed that B-N-I is basically an α-1→4 glucan, with branches on C6; B-I-I is a heavily branched α-mannan with 1→2 linked main chain. B-II-I and B-II-II, have a backbone of rhamno-galacturonan with 1→2 linked l-rhamnose interspersed with 1→4 linked galacturonic acid. Structure-activity relationship analysis indicated that monosaccharide compositions, molecular weight, certain structural units (rhamno-galacturonan type I and arabinogalactan type II) are the principal factors responsible for potent complement fixating and macrophage-stimulating activities. Their immunomodulating activities may, at least partly, explain the health benefits of the mushroom.

Differential inhibitory potencies and mechanisms of the type I ribosome inactivating protein marmorin on estrogen receptor (ER)-positive and ER-negative breast cancer cells

Breast cancer is the second most common cancer with a high incidence rate worldwide. One of the promising therapeutic approaches on breast cancer is to use the drugs that target the estrogen receptor (ER). In the present investigation, marmorin, a type I ribosome inactivating protein from the mushroom Hypsizigus marmoreus, inhibited the survival of breast cancer in vitro and in vivo. It evinced more potent cytotoxicity toward estrogen receptor (ER)-positive MCF7 breast cancer cells than ER-negative MDA-MB-231 cells. Further study disclosed that marmorin undermined the expression level of estrogen receptor α (ERα) and significantly inhibited the proliferation of MCF7 cells induced by 17β-estradiol. Knockdown of ERα in MCF7 cells significantly attenuated the inhibitory effect of marmorin on proliferation, suggesting that the ERα-mediated pathway was implicated in the suppressive action of marmorin on ER-positive breast cancer cells. Moreover, marmorin induced time-dependent apoptosis in both MCF7 and MDA-MB-231 cells. It brought about G2/M-phase arrest, mitochondrial membrane potential depolarization and caspase-9 activation in MCF7 cells, and to a lesser extent in MDA-MB-231 cells. Marmorin triggered the death receptor apoptotic pathway (e.g. caspase-8 activation) and endoplasmic reticulum stress (ERS, as evidenced by phosphorylation of PERK and IRE1α, cleavage of caspase-12, and up-regulation of CHOP expression) in both MCF7 and MDA-MB-231 cells. In summary, marmorin exhibited inhibitory effect on breast cancer partially via diminution of ERα and apoptotic pathways mediated by mitochondrial, death receptor and ERS. The results advocate that marmorin is a potential candidate for breast cancer therapy.

Anti-inflammation and antioxidant effect of Cordymin, a peptide purified from the medicinal mushroom Cordyceps sinensis, in middle cerebral artery occlusion-induced focal cerebral ischemia in rats

Cordymin is a peptide purified from the medicinal mushroom Cordyceps sinensis. The present study investigated the effects of Cordymin in prevention of focal cerebral ischemic/reperfusion (IR) injury. The right middle cerebral artery occlusion model was used in the study. The effects of Cordymin on mortality rate, neurobehavior, grip strength, glutathione content, lipid Peroxidation, glutathione peroxidase activity, glutathione reductase activity, catalase activity, Na(+)K(+)ATPase activity glutathione S transferase activity and on the regulation of C3 and C4 protein level, polymorphonuclear cells, interleukin-1β and tumor necrosis factor-α in a rat model were studied respectively. Treatment (orally) of Cordymin significantly boosted the defense mechanism against cerebral ischemia by increasing antioxidants activity related to lesion pathogenesis. Restoration of the antioxidant homeostasis in the brain after reperfusion may have helped the brain recover from ischemic injury. Moreover, Cordymin significantly inhibited infiltration of polymorphonuclear cells and IR-induced up-regulation of the brain production of C3 protein level, interleukin-1β and tumor necrosis factor-α. Cordymin significantly improved the outcome in rats after cerebral ischemia and reperfusion in terms of neurobehavioral function. Our findings suggest that cordymin have a neuroprotective effect in the ischemic brain, which is due to the inhibition of inflammation and increase of antioxidants activity related to lesion pathogenesis. Cordymin can be used as potential preventive agent against cerebral ischemia-reperfusion injury.

Bitter melon (Momordica charantia) extract suppresses adrenocortical cancer cell proliferation through modulation of the apoptotic pathway, steroidogenesis, and insulin-like growth factor type 1 receptor/RAC-α serine/threonine-protein kinase signaling

Adrenocortical carcinomas are rare but present with extremely poor prognosis. One of the approaches to control cancer progression and reduce cancer risk is prevention through diet. Bitter melon is widely consumed as a vegetable and especially as a traditional medicine in many countries. In this study, we have used human and mouse adrenocortical cancer cells as an in vitro model to assess the efficacy of bitter melon extract (BME) as an anticancer agent. The protein concentrations of BME and other extracts were measured before use. First, BME treatment of adrenocortical cancer cells resulted in a significantly dose-dependent decrease in cell proliferation. However, we did not observe an antiproliferative effect in adrenocortical cancer cells treated with extracts from blueberry, zucchini, and acorn squash. Second, apoptosis of adrenocortical cancer cells was accompanied by increased caspase-3 activation and poly(ADP-ribose) polymerase cleavage. BME treatment enhanced cellular tumor antigen p53, cyclin-dependent kinase inhibitor 1A (also called p21), and cyclic AMP-dependent transcription factor-3 levels and inhibited G1/S-specific cyclin D1, D2, and D3, and mitogen-activated protein kinase 8 (also called Janus kinase) expression, suggesting an additional mechanism involving cell cycle regulation and cell survival. Third, BME treatment decreased the key proteins involved in steroidogenesis in adrenocortical cancer cells. BME treatment decreased the level of phosphorylation of cyclin-dependent kinase 7, which is required, at least in part, for steroidogenic factor 1 activation. Finally, we observed that BME treatment significantly reduced the level of insulin-like growth factor 1 receptor and its downstream signaling pathway as evidenced by lower levels of phosphorylated RAC-α serine/threonine-protein kinase. Taken together, these data illustrate the inhibitory effect of bitter melon on cell proliferation of adrenocortical cancer through modulation of diverse mechanisms.

Isolation and characterization of a Kunitz-type trypsin inhibitor with antiproliferative activity from Gymnocladus chinensis (Yunnan bean) seeds

A 20-kDa Kunitz-type trypsin inhibitor was isolated from Gymnocladus chinensis (Yunnan bean) seeds. The isolation procedure involved ion exchange chromatography on diethylaminoethyl cellulose (DEAE-cellulose), affinity chromatography on Affi-gel blue gel, ion exchange chromatography on sulfopropyl sepharose (SP-sepharose), and gel filtration by FPLC on Superdex 75. The trypsin inhibitor was adsorbed on DEAE-cellulose, unadsorbed on Affi-gel blue gel, and adsorbed on SP-Sepharose. It dose-dependently inhibited trypsin with an IC₅₀ value of 0.4 μM. Dithiothreitol reduced its trypsin inhibitory activity, suggesting that an intact disulfide bond is indispensable to the activity. It suppressed [methyl-³H] thymidine incorporation by leukemia L1210 cells and lymphoma MBL2 cells with an IC₅₀ value of 4.7 and 9.4 μM, respectively. There was no effect on human immunodeficiency virus⁴-1 reverse transcriptase activity and fungal growth when the trypsin inhibitor was tested up to 100 μM.

Cordymin, an antifungal peptide from the medicinal fungus Cordyceps militaris

Cordymin, an antifungal peptide with a molecular mass of 10,906 Da and an N-terminal amino acid sequence distinct from those of previously reported proteins, was purified from the medicinal mushroom Cordyceps militaris. The isolation protocol comprised ion exchange chromatography of the aqueous extract on SP-Sepharose and Mono S and gel filtration on Superdex 75 by a fast protein liquid chromatography system. Cordymin was adsorbed on both cation exchangers. The peptide inhibited mycelial growth in Bipolaris maydis, Mycosphaerella arachidicola, Rhizoctonia solani and Candida albicans with an IC(50) of 50 μM, 10 μM, 80 μM, and 0.75 mM, respectively. However, there was no effect on Aspergillus fumigatus, Fusarium oxysporum and Valsa mali when tested up to 2 mM. The antifungal activity of the peptide was stable up to 100°C and in the pH range 6-13, and unaffected by 10 mM Zn(2+) and 10 mM Mg(2+). Cordymin inhibited HIV-1 reverse transcriptase with an IC(50) of 55 μM. Cordymin displayed antiproliferative activity toward breast cancer cells (MCF-7) but there was no effect on colon cancer cells (HT-29). There was no mitogenic activity toward mouse spleen cells and no nitric oxide inducing activity toward mouse macrophages when tested up to 1 mM.

An antifungal defensin from Phaseolus vulgaris cv. 'Cloud Bean'

An antifungal peptide with a defensin-like sequence and exhibiting a molecular mass of 7.3kDa was purified from dried seeds of Phaseolus vulgaris 'Cloud Bean'. The isolation procedure entailed anion exchange chromatography on DEAE-cellulose, affinity chromatography an Affi-gel blue gel, cation exchange chromatography on SP-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. Although the antifungal peptide was unadsorbed on DEAE-cellulose, it was adsorbed on both Affi-gel blue gel and SP-Sepharose. The antifungal peptide exerted antifungal activity against Mycosphaerella arachidicola with an IC(50) value of 1.8 μM. It was also active against Fusarium oxysporum with an IC(50) value of 2.2 μM. It had no inhibitory effect on HIV-1 reverse transcriptase when tested up to 100 μM. Proliferation of L1210 mouse leukemia cells and MBL2 lymphoma cells was inhibited by the antifungal peptide with an IC(50) of 10 μM and 40 μM, respectively.

Commonly consumed and specialty dietary mushrooms reduce cellular proliferation in MCF-7 human breast cancer cells

Worldwide, over one million women will be newly diagnosed with breast cancer in the next year. Moreover, breast cancer is the second leading cause of cancer death in the USA. An accumulating body of evidence suggests that consumption of dietary mushrooms can protect against breast cancer. In this study, we tested and compared the ability of five commonly consumed or specialty mushrooms to modulate cell number balance in the cancer process using MCF-7 human breast cancer cells. Hot water extracts (80°C for 2 h) of maitake (MT, Grifola frondosa), crimini (CRIM, Agaricus bisporus), portabella (PORT, Agaricus bisporus), oyster (OYS, Pleurotus ostreatus) and white button (WB, Agaricus bisporus) mushrooms or water alone (5% v/v) were incubated for 24 h with MCF-7 cells. Cellular proliferation determined by bromodeoxyuridine incorporation was significantly ( P < 0.05) reduced up to 33% by all mushrooms, with MT and OYS being the most effective. MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) reduction, an often used mitochondrion-dependent marker of proliferation, was unchanged although decreased ( P > 0.05) by 15% with OYS extract. Lactate dehydrogenase release, as a marker of necrosis, was significantly increased after incubation with MT but not with other test mushrooms. Furthermore, MT extract significantly increased apoptosis, or programmed cell death, as determined by terminal deoxynucleotidyl end labeling method, whereas other test mushrooms displayed trends of ∼15%. The total numbers of cells per flask, determined by hemacytometry, were not different from control cultures. Overall, all test mushrooms significantly suppressed cellular proliferation, with MT further significantly inducing apoptosis and cytotoxicity in human breast cancer cells. This suggests that both common and specialty mushrooms may be chemoprotective against breast cancer.