Antibacterial activity of ergosterol peroxide against Mycobacterium tuberculosis: dependence upon system and medium employed

Efficacy of ergosterol peroxide obtained from the endophytic fungus Acrophialophora jodhpurensis against Rhizoctonia solani

AIM

To investigate antifungal activity of the extract and major metabolite of the endophytic fungus Acrophialophora jodhpurensis (belonging to Chaetomiaceae) against crown and root rot caused by Rhizoctonia solani (teleomorph: Thanatephorus cucumeris), as an important pathogen of tomato.

METHODS AND RESULTS

The endophytic fungus A. jodhpurensis, has high inhibitory effect against R. solani AG4-HG II in vitro and in vivo. The media conditions were optimized for production of the endophyte's metabolites. The highest amounts of secondary metabolites were produced at pH 7, 30°C temperature, and in the presence of 0.5% glucose, 0.033% sodium nitrate, and 1 gl-1 asparagine as the best carbon, nitrogen, and amino acid sources, respectively. The mycelia were extracted by methanol and the obtained extract was submitted to various chromatography techniques. Phytochemical analysis via thin-layer chromatography (TLC) and nuclear magnetic resonance (NMR) spectroscopy showed that ergosterol peroxide was the major component in the extract of this endophyte. Antifungal activities of the methanolic extract and ergosterol peroxide in the culture media were studied against R. solani. Minimum inhibitory concentrations of the extract and ergosterol peroxide against the pathogen were 600 and 150 µg ml-1, respectively. Ergosterol peroxide revealed destructive effects on the pathogen structures in microscopic analyses and induced sclerotia production. Histochemical analyses revealed that it induced apoptosis in the mycelia of R. solani via superoxide production and cell death. Application of ergosterol peroxide in the leaf disc assay reduced the disease severity in tomato leaves.

CONCLUSIONS

Antifungal metabolites produced by A. jodhpurensis, such as ergosterol peroxide, are capable of controlling destructive Rhizoctonia diseases on tomato.

Chemical Defence by Sterols in the Freshwater Ciliate Stentor polymorphus

Heterotrich ciliates typically retain toxic substances in specialized ejectable organelles, called extrusomes, which are used in predator-prey interactions. In this study, we analysed the chemical defence strategy of the freshwater heterotrich ciliate Stentor polymorphus against the predatory ciliate Coleps hirtus, and the microturbellarian flatworm Stenostomum sphagnetorum. The results showed that S. polymorphus is able to defend itself against these two predators by deploying a mix of bioactive sterols contained in its extrusomes. Sterols were isolated in vivo and characterized by liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR), as ergosterol, 7-dehydroporiferasterol, and their two peroxidized analogues. The assessment of the toxicity of ergosterol and ergosterol peroxide against various organisms, indicated that these sterols are essential for the effectiveness of the chemical defence in S. polymorphus.

The Role of Ingenane Diterpenes in Cancer Therapy: From Bioactive Secondary Compounds to Small Molecules

Diterpenes are a class of critical taxonomic markers of the Euphorbiaceae family, representing small compounds (eg, molecules) with a wide range of biological activities and multi-target therapeutic potential. Diterpenes can exert different activities, including antitumor and multi-drug resistance-reversing activities, and antiviral, immunomodulatory, and anti-inflammatory effects, mainly due to their great structural diversity. In particular, one polycyclic skeleton has been highlighted: ingenane. Besides this natural diterpene, promising polycyclic skeletons may be submitted to chemical modification—by in silico approaches, chemical reactions, or biotransformation—putatively providing more active analogs (eg, ingenol derivatives), which are currently under pre-clinical investigation. This review outlines the current mechanisms of action and potential therapeutic implications of ingenol diterpenes as small cancer molecules.

Traditional Medicinal Plants as a Source of Antituberculosis Drugs: A System Review

Medicinal plants are the chief components in the different oriental formulations in different traditional medical systems worldwide. As a thriving source of medicine, the medicinal plants with antituberculosis (TB) properties inspire the pharmacists to develop new drugs based on their active components or semimetabolites. In the present review, the anti-TB medicinal plants were screened from the scientific literatures, based on the botanical classification and the anti-TB activity. The obtained anti-TB medicinal plants were categorized into three different categories, viz., 159 plants critically examined with a total 335 isolated compounds, 131 plants with their crude extracts showing anti-TB activity, and 27 plants in literature with the prescribed formula by the traditional healers. Our systemic analysis on the medicinal plants can assist the discovery of novel and more efficacious anti-TB drugs.

Isolation, purification and identification of biological compounds from Beauveria sp. and their evaluation as insecticidal effectiveness against Bemisia tabaci

Bemisia tabaci is one of the most notorious agricultural pests in the world. A vicious circle among insect resistance, dose increased, environment and human body impaired as the overuse of synthetic pesticides are becoming increasingly evident. Entomopathogenic Beauveria sp. is known as an effective natural enemy to control B. tabaci. Therefore, this study aimed to purify and identify the biological compounds from Beauveria sp. LY2 via extensive chromatographic techniques, NMR and MS and evaluated for their insecticidal activities against B. tabaci via contact and feeding assay. The outcome identified that one new cerebroside, cerebroside F (1), nine known compounds, cerebroside B (2), bassiatin (3), methyl 1,4-dihydro-4-oxo-2-quinolinecarboxylate (4), cerevisterol (5), 9-hydroxycerevisterol (6), 6-dehydrocerevisterol (7), (22E,24R)-ergosta-8(14),22-diene-3β,5α,6β,7α-tetrol (8), melithasterol B (9) and ergosterol peroxide (10) were isolated. Among the known compounds, methyl 1,4-dihydro-4-oxo- 2-quinolinecarboxylate (4) was isolated from natural origin for the first time. It is demonstrable from the results that compounds 3, 4 and 7 strongly featured insecticidal activities against B. tabaci, being the LC₅₀ value as 10.59, 19.05, 26.59 μg/mL respectively in contact as well as 11.42, 5.66, 5.65 μg/mL respectively in feeding experiment. Moreover, no adverse effect on plant growth/height or phytotoxicity was observed on pepper, cucumber, tomato and cotton. The data from the current study has provided the foundation for the use of newly purified compounds against Bemisia tabaci as an alternative to synthetic chemical compounds.

New Conjugated Compound T5 Epidioxy-Sterol-ANB Inhibits the Growth of Mycobacterium tuberculosis Affecting the Cholesterol and Folate Pathways

The upsurge and persistence of drug resistant strains of Mycobacterium tuberculosis (Mtb) is an important limitant to the battery of drugs available for the elimination of tuberculosis (TB). To avoid future scarcity of antibiotics against Mtb, it is important to discover new effective anti-mycobacterial agents. In this study, we present data from a series of experiments to determine in vitro and in vivo anti-mycobacterial activity of a library of epidioxy-sterol analogs. We test 15 compounds for their ability to reduce the viability of Mtb. We found that one compound called T5 epidioxy-sterol-ANB display significant potency against Mtb in vitro specifically inside macrophages but without effectivity in axenic cultures. A viability assay confirms that this T5 compound is less toxic for macrophages in vitro as compared to the current Mtb drug Rifampicin at higher concentrations. We use a transcriptomic analysis of Mtb inside macrophages after T5 epidioxy-sterol-ANB treatment, and we found a significant down-regulation of enzymes involved in the cholesterol and folic acid pathways. In vivo, significant differences were found in the lungs and spleen CFUs of Mtb infected mice treated with the T5 epidioxy-sterol-ANB as compared with the untreated control group, which provides additional evidence of the effectivity of the T5 compound. Altogether these results confirm the potential of this T5 epidioxy-sterol-ANB compound against Mtb.

Anti-diabetic effects of Grifola frondosa bioactive compound and its related molecular signaling pathways in palmitate-induced C2C12 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Grifola frondosa (GF), a high value medicinal mushroom, is popularly consumed as traditional medicines and health foods in China and Japan. It is a herbal medicine traditionally used for treating inflammation, cancer and diabetes.

AIM OF THE STUDY

This study aimed to examine the anti-diabetic effects of a GF bioactive compound ergosterol peroxide (EPO), and its mechanism(s) of action in palmitate (PA)-induced C2C12 cells.

MATERIALS AND METHODS

EPO was isolated and purified from GF fruiting bodies, and used to test for anti-diabetic activity in PA-induced murine C2C12 skeletal muscle cells through measuring glucose uptake, intracellular ROS production, and expressions of MAPKs, IRS-1, PI3K, Akt and GLUT-4 proteins.

RESULTS

EPO significantly up-regulated glucose absorption and increased cell growth. At 5 μM, EPO significantly enhanced glucose uptake and decreased ROS formation, as well as up-regulated the expression of IRS-1, p-IRS-1, PI3K, Akt, p-Akt, and GLUT-4 proteins in PA-induced cells, while their p-JNK and p-p38 expression were down-regulated. GLUT-4 siRNA treatment effectively down-regulated the EPO-induced absorption of glucose and inhibited the expression of GLUT-4.

CONCLUSION

These results suggest that the anti-diabetic effect of GF was from its bioactive compound EPO through the inhibition of ROS production, up-regulation of glucose absorption, and modulation of PI3K/Akt, MAPKs and GLUT-4 signaling transduction pathways.

Phellinus linteus Grown on Germinated Brown Rice Inhibits IgE-Mediated Allergic Activity through the Suppression of FcεRI-Dependent Signaling Pathway In Vitro and In Vivo

Phellinus linteus (PL) has been used as a traditional herbal medicine owing to its immune regulatory activity. Previous studies reported that PL grown on germinated brown rice (PBR) exerted immunomodulatory, anticancer, and anti-inflammatory activities. However, role of PBR on type I hypersensitive reactions has not been studied yet. We found that PBR contained more polyphenolic compounds than PL extract. Among fractions, PBR butanol fraction (PBR-BuOH) significantly contained the most amounts of total polyphenolic contents compared with all extracts or fractions. In this study, anti-allergic activity of PBR-BuOH was examined using in vitro and in vivo models of immunoglobulin E/antigen- (IgE/Ag-) stimulated allergy. The inhibitory activity of degranulation was higher in PBR-BuOH (IC₅₀ 41.31 ± 0.14 μg/mL) than in PL-BuOH (IC₅₀ 108.07 ± 8.98 μg/mL). We observed that PBR-BuOH suppressed calcium influx and the level of TNF-α and IL-4 mRNA expression in a dose-dependent manner. The phosphorylation of Fyn, Gab2, PI3K, Syk, and IκB protein is reduced by PBR-BuOH. Oral administration of PBR-BuOH inhibited allergic reactions including the extravasation of Evans blue dye, ear swelling, and infiltration of immune cells in mice with passive cutaneous anaphylaxis (PCA). These findings suggest that PBR-BuOH might be used as a functional food, a health supplement, or a drug for preventing type I hypersensitive allergic disease.

Insights into Ergosterol Peroxide's Trypanocidal Activity

Trypanosoma cruzi, which causes Chagas disease, is a significant health threat in many countries and affects millions of people. Given the magnitude of this disease, a broader understanding of trypanocidal mechanisms is needed to prevent and treat infection. Natural endoperoxides, such as ergosterol peroxide, have been shown to be toxic to parasites without causing harm to human cells or tissues. Although prior studies have demonstrated the trypanocidal activity of ergosterol peroxide, the cellular and molecular mechanisms remain unknown. The results of this study indicate that a free-radical reaction occurs in T. cruzi following ergosterol peroxide exposure, leading to cell death. Using a combination of biochemical, microscopic and in silico experimental approaches, we have identified, for the first time, the cellular and molecular cytotoxic mechanism of an ergosterol peroxide obtained from Pleurotus ostreatus (Jacq) P. Kumm. f. sp. Florida.

Development of ergosterol peroxide probes for cellular localisation studies

Ergosterol peroxide selectively exhibits biological activity against a wide range of diseases; however, its mode of action remains unknown. Here, we present an efficient synthesis of ergosterol peroxide chemical probes for in vitro anticancer evaluation, live cell studies and proteomic profiling. Ergosterol peroxide analogues show promising anti-proliferation activity against triple negative breast cancer cellular models, revealing information on the structure-activity relationship of this natural product in order to develop superior analogues. The combined cellular studies demonstrate that ergosterol peroxide is distributed across the cytosol with significant accumulation in the endoplasmic reticulum (ER). These chemical probes support our efforts towards uncovering the potential target(s) of ergosterol peroxide against triple negative breast cancer cell lines.

Quercetin 3-O-glucoside recovered from the wild Egyptian Sahara plant, Euphorbia paralias L., inhibits glutamine synthetase and has antimycobacterial activity

Tuberculosis remains a major health problem accentuated by the rise of resistance to all available drugs. Therefore, this study was launched to discover a novel antituberculosis agent from wild Egyptian Sahara plants. Twelve such plants were screened, in vitro, for their activity against various Mycobacterium species. The most active plant, Euphorbia paralias, was further fractionated with different organic solvents, and the activity of the obtained fractions was determined by the agar diffusion and broth microdilution methods. The methanol fraction was the most active against Mycobacterium spp., and was non-toxic in doses up to 10 g/kg of animal weight. Its main component was separated by column chromatography, and then identified by ultraviolet spectroscopy and nuclear magnetic resonance analysis as quercetin-3-O-β-D-glucoside. Docking analysis suggested that quercetin-3-O-β-D-glucoside inhibits the glutamine synthetase enzyme, a promising target for the development of antituberculosis drugs. This prediction was confirmed by an in vitro glutamine synthetase biosynthetic assay. To the best of our knowledge, and based on bioinformatics mining of the BioPhytMol database, this is the first report on the antimycobacterial activity of Euphorbia paralias plant. It is also the first report on the inhibition of mycobacterial glutamine synthetase by the flavonoid quercetin.

Syntheses of 7-dehydrocholesterol peroxides and their improved anticancer activity and selectivity over ergosterol peroxide

Three 7-dehydrocholesterol peroxides were photochemically prepared and their anticancer activity was studied.

Phytochemicals for human disease: An update on plant-derived compounds antibacterial activity

In recent years, many studies have shown that phytochemicals exert their antibacterial activity through different mechanisms of action, such as damage to the bacterial membrane and suppression of virulence factors, including inhibition of the activity of enzymes and toxins, and bacterial biofilm formation. In this review, we summarise data from the available literature regarding the antibacterial effects of the main phytochemicals belonging to different chemical classes, alkaloids, sulfur-containing phytochemicals, terpenoids, and polyphenols. Some phytochemicals, besides having direct antimicrobial activity, showed an in vitro synergistic effect when tested in combination with conventional antibiotics, modifying antibiotic resistance. Review of the literature showed that phytochemicals represent a possible source of effective, cheap and safe antimicrobial agents, though much work must still be carried out, especially in in vivo conditions to ensure the selection of effective antimicrobial substances with low side and adverse effects.

The Amoebicidal Effect of Ergosterol Peroxide Isolated from Pleurotus ostreatus

Dysentery is an inflammation of the intestine caused by the protozoan parasite Entamoeba histolytica and is a recurrent health problem affecting millions of people worldwide. Because of the magnitude of this disease, finding novel strategies for treatment that does not affect human cells is necessary. Ergosterol peroxide is a sterol particularly known as a major cytotoxic agent with a wide spectrum of biological activities produced by edible and medicinal mushrooms. The aim of this report is to evaluate the amoebicidal activity of ergosterol peroxide (5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol isolated from 5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) (Jacq.) P. Kumm. f. sp. Florida. Our results show that ergosterol peroxide produced a strong cytotoxic effect against amoebic growth. The inhibitory concentration IC50 of ergosterol peroxide was evaluated. The interaction between E. histolytica and ergosterol peroxide in vitro resulted in strong amoebicidal activity (IC50  = 4.23 nM) that may be due to the oxidatory effect on the parasitic membrane. We also tested selective toxicity of ergosterol peroxide using a cell line CCL-241, a human epithelial cell line isolated from normal human fetal intestinal tissue. To the best of our knowledge, this is the first report on the cytotoxicity of ergosterol peroxide against E. histolytica, which uncovers a new biological property of the lipidic compound isolated from Pleurotus ostreatus (Jacq.) P. Kumm. f. sp. Florida.

Peroxy natural products

This review covers the structures and biological activities of peroxy natural products from a wide variety of terrestrial fungi, higher plants, and marine organisms. Syntheses that confirm or revise structures or stereochemistries have also been included, and 406 references are cited.

Role of Phenothiazines and Structurally Similar Compounds of Plant Origin in the Fight against Infections by Drug Resistant Bacteria

Phenothiazines have their primary effects on the plasma membranes of prokaryotes and eukaryotes. Among the components of the prokaryotic plasma membrane affected are efflux pumps, their energy sources and energy providing enzymes, such as ATPase, and genes that regulate and code for the permeability aspect of a bacterium. The response of multidrug and extensively drug resistant tuberculosis to phenothiazines shows an alternative therapy for the treatment of these dreaded diseases, which are claiming more and more lives every year throughout the world. Many phenothiazines have shown synergistic activity with several antibiotics thereby lowering the doses of antibiotics administered to patients suffering from specific bacterial infections. Trimeprazine is synergistic with trimethoprim. Flupenthixol (Fp) has been found to be synergistic with penicillin and chlorpromazine (CPZ); in addition, some antibiotics are also synergistic. Along with the antibacterial action described in this review, many phenothiazines possess plasmid curing activities, which render the bacterial carrier of the plasmid sensitive to antibiotics. Thus, simultaneous applications of a phenothiazine like TZ would not only act as an additional antibacterial agent but also would help to eliminate drug resistant plasmid from the infectious bacterial cells.

Osteoclastogenesis Inhibitory Effect of Ergosterol Peroxide Isolated from Pleurotus eryngii

Ergosterol peroxide was isolated from the ethanol extract of Pleurotus eryngii as an inhibitor of osteoclast differentiation. This compound showed an inhibitory effect in a dose-dependent manner and an inhibition rate of up to 62% with low cytotoxicity, even at a concentration as low as 1.0 μg/mL.

Ergosterol peroxide isolated from Ganoderma lucidum abolishes microRNA miR-378-mediated tumor cells on chemoresistance

Due to an altered expression of oncogenic factors and tumor suppressors, aggressive cancer cells have an intrinsic or acquired resistance to chemotherapeutic agents. This typically contributes to cancer recurrence after chemotherapy. microRNAs are short non-coding RNAs that are involved in both cell self-renewal and cancer development. Here we report that tumor cells transfected with miR-378 acquired properties of aggressive cancer cells. Overexpression of miR-378 enhanced both cell survival and colony formation, and contributed to multiple drug resistance. Higher concentrations of chemotherapeutic drugs were needed to induce death of miR-378-transfected cells than to induce death of control cells. We found that the biologically active component isolated from Ganoderma lucidum could overcome the drug-resistance conferred by miR-378. We purified and identified the biologically active component of Ganoderma lucidum as ergosterol peroxide. We demonstrated that ergosterol peroxide produced greater activity in inducing death of miR-378 cells than the GFP cells. Lower concentrations of ergosterol peroxide were needed to induce death of the miR-378-transfected cells than in the control cells. With further clinical development, ergosterol peroxide represents a promising new reagent that can overcome the drug-resistance of tumor cells.

Ajuga remota Benth.: from ethnopharmacology to phytomedical perspective in the treatment of malaria

Treatment and control of malaria have become more difficult with the spread of drug-resistant parasites and insecticide-resistant mosquito vectors. In the search for new antimalarial drugs, ethnopharmacological sources should merit more attention. Establishing the safety of traditional herbal medicines, along with identifying their active principles, are essential steps in the production of a properly standardized and accessible herbal medicine. Phytochemical characterization could also serve as a base for the development of new chemical compounds. The genus of Ajuga belongs to the family Lamiaceae and contains at least 301 species. Many of these plants have been used in traditional medicine. Ajuga remota in particular is traditionally used as a herbal remedy for fever and infections, and is prescribed for malaria by 66% of the Kenyan herbalists. A large number of compounds have already been isolated from A. remota, including ergosterol-5,8-endoperoxide (6), ajugarin-I (1), 8-O-acetylharpagide (5) and several phytoecdysteroids. In vitro pharmacological studies have been conducted on constituents of A. remota of which some of them displayed a concentration-dependent inhibition of chloroquine-sensitive and -resistant Plasmodium falciparum and Mycobacterium tuberculosis. Inhibition of parasitaemia was demonstrated in mouse models with P. berghei, supporting the traditional use of the plant against malaria. In this state-of-the-art review, A. remota as a possible therapeutic tool for malaria is discussed.

Antitumor activity of terpenoids against classical and atypical multidrug resistant cancer cells

Nineteen terpenoids, including macrocyclic diterpenes, diterpenic lactones and other polycyclic diterpenes, steroids and a triterpene isolated from the methanolic extracts of Euphorbia species, were evaluated for their potential antineoplastic activity in various human cancer cell lines that were derived from three tumor entities: gastric (EPG85-257), pancreatic (EPP85-181) and colon (HT-29) carcinomas. Furthermore, different multidrug-resistant variants of these cancer cell lines with over-expression of MDR1/P-gp or no MDR1/P-gp expression were also investigated. In parental drug-sensitive cell lines, the tested compounds showed a moderate/weak antiproliferative effect or were inactive. Most of them were found more effective in drug-resistant cells than in the parental, drug-sensitive ones, and some of them showed high antineoplastic efficacy in classical or atypical drug-resistant cells. The most active compounds were the lathyrane diterpenes latilagascenes C and D, and the diterpenic lactones 3beta-acetoxy-helioscopinolide B and helioscopinolide E which exhibited high antineoplastic activities against the drug-resistant subline EPG85-257RDB derived from gastric carcinoma. In addition, the macrocyclic lathyrane diterpene jolkinol B was found to be highly effective in the multidrug-resistant variant HT-29RNOV.

Chemical constituents of Stereum subtomentosum and two other birch-associated basidiomycetes: an interspecies comparative study

Metabolites of the wood-rotting fungus Stereum subtomentosum Pouzar (Basidiomycetes, order Russulales, family Stereaceae) occurring on birch (Betula pendula Roth) trees were phytochemically investigated for the first time. Three main metabolite chemotypes present in MeOH extracts of the fruit bodies, viz. steroids, fatty acids, and water-soluble sugars, were fractionated, isolated, and identified by 1D/2D NMR-spectroscopic analyses, NMR data comparisons, and chemical correlations combined with GC/MS experiments. Thirteen compounds including two 5 alpha,8 alpha-epidioxy steroids, alpha,alpha'-trehalose, D-arabinitol, D-mannitol, and saturated/unsaturated fatty acids, were identified. Differences among S. subtomentosum and two other birch-associated fungal species, Trametes versicolor (L.: Fr.) Pilát, and Piptoporus betulinus (Bull.: Fr.) P. Karst (Basidiomycetes, order Polyporales, family Polyporaceae) were evaluated as regards the richness and abundance relationships in metabolite profiling.