A review on antimicrobial activity of mushroom (Basidiomycetes) extracts and isolated compounds

Despite the huge diversity of antibacterial compounds, bacterial resistance to first choice antibiotics has been drastically increasing. Moreover, the association between multi-resistant microorganisms and nosocomial infections highlight the problem, and the urgent need for solutions. Natural resources have been exploited in the last years and among them mushrooms could be an alternative as source of new antimicrobials. In this review we present an overview about the antimicrobial properties of mushroom extracts, highlight some of the active compounds identified including low and high molecular weight (LMW and HMW, respectively) compounds. LMW compounds are mainly secondary metabolites, such as sesquiterpenes and other terpenes, steroids, anthraquinones, benzoic acid derivatives, and quinolines, but also primary metabolites such as oxalic acid. HMW compounds are mainly peptides and proteins. Data available from literature indicate a higher antimicrobial activity of mushroom extracts against Gram-positive bacteria. Among all the mushrooms, Lentinus edodes is the most studied species and seems to have a broad antimicrobial action against both Gram-postive and Gram-negative bacteria. Plectasin peptide, obtained from Pseudoplectania nigrella, is the isolated compound with highest antimicrobial activity against Gram-positive bacteria, while 2-aminoquinoline, isolated from Leucopaxillus albissimus, presents the highest antimicrobial activity against Gram-negative bacteria

Wild mushroom extracts potentiate the action of standard antibiotics against multiresistant bacteria

Aims: The main objective of the present work was to evaluate the capacity of wild mushroom extracts to potentiate the action of standard antibiotics, through synergisms that allow a decrease in their therapeutic doses and ultimately contribute to the reduction of resistances. Methods and Results: Wild mushroom extracts were applied to different multi-resistant microorganisms (Escherichia coli, Extended-spectrum beta-lactamase-producing (ESBL) Escherichia coli and Methicillin-resistant Staphylococcus aureus (MRSA), combined with commercial antibiotics (Penicillin, Ampicillin, Amoxicillin/Clavulanic acid, Cefoxitin, Ciprofloxacin, Cotrimoxazol, Levofloxacin). Microdilution method was used to determine minimum inhibitory concentrations (MICs). The results obtained showed higher synergistic effects against MRSA than against E. coli. Mycena rosea and Fistulina hepatica were the best extracts for synergistic effects against MRSA. The efficiency of Russula delica extract against E. coli 1 (resistant to Ampicillin, Ciprofloxacin and Trimethoprim/Sulfasoxazole) and E. coli 2 (resistant to Amoxicillin/Clavulanic acid and Ampicillin) was higher than that of Leucopaxillus giganteus extract; nevertheless the latter extract exhibited better synergistic effects against ESBL E. coli. Conclusions: This study shows that, similarly to plants, some mushroom extracts can potentiate the action of antibiotics extensively used in clinical practice for Gram-positive or Gram-negative bacteria, with positive action even against multi-resistant bacteria. Significance and Impact of the Study: Mushroom extracts could decrease therapeutic doses of standard antibiotics and reduce microorganism’s resistance to those drugs.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU for financial support to this work (research project PTDC/AGR-ALI/110062/2009; strategic projects PEst-OE/ AGR/UI0690/2011 and PEst-OE/EQB/LA0016/2011). They also thank to CHTMAD – Hospital Center of Tr as-os- Montes e Alto Douro and Siemens for all the support

SNekoliko rijetkih vrsta viših gljiva i njihovi lokaliteti u Jugoslaviji

Localities in Jugoslavia are presented for the following rare species of higher fungi: Sistotrema confluens, Baeospora myriadophylla and Le- piota bucknallii, with two localities each, Hymenochaete mougeotxi with five, and Leucopaxillus amarus with eight. It is to be hoped that some of them at least will also be found elsewhere. Except for L. amarus, all are published here for the first time for our country.Prikazani su lokaliteti ovih rijetkih vrsta viših gljiva u Jugoslaviji: Sistotrema confluens, Baeospora myriadophylla i Lepiota bucknallii, svaka s dva lokaliteta, Hymenochaete mougeotii s pet i Leucopaxillus amarus s osam. Vjerojatno će bar neke od njih biti nađene i drugdje. Osim L. amarus, sve su ostale ovdje prvi put zabilježene za našu zemlju

Bioactive properties of the medicinal mushroom Leucopaxillus giganteus mycelium obtained in the presence of different nitrogen sources

Leucopaxillus mushroom species are used in the chemical industry for extraction of clitocybin antibiotic and particularly the edible mushroom Leucopaxillus giganteus can be found in Northeast Portugal. Nevertheless, the production of its mycelium for pharmacological applications has not been explored. Herein, the mycelium obtained in the presence of four different nitrogen sources was investigated with regard to phenol production and antimicrobial and antioxidant properties. Phenol concentration increased along the growth time as a response to the oxidative stress and therefore free radical production. Although significant differences for mycelium growth between the nitrogen sources had not been observed, (NH4)2HPO4 proved to be the most appropriate to increase bioactive properties, leading to the highest phenol content and lowest EC50 and MIC values. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. The samples selectively inhibited the growth of Gram positive bacteria, Staphylococcus aureus being the most susceptible one. Gram negative bacteria and fungi were resistant to the extracts. Antioxidant activity was calculated by the reducing power assay, the scavenging effect on DPPH radicals, and hemolysis and lipid peroxidation inhibition. Significantly negative linear regressions were established between phenols/flavonoids contents, which increased along the mycelia growth time and antioxidant activity

Wild mushroom extracts potentiate the action of standard antibiotics against multi-resistant bacteria

The indiscriminate use of antibiotics and chemotherapeutic agents and the genetic ability of bacteria to transmit and acquire resistance resulted in the development of resistant species. In the last few years, several studies have been conducted in different countries to demonstrate the efficacy of natural products, not only studying their direct antimicrobial activity but also their capacity as resistance-modifying agents. The main objective of the present work was to evaluate the capacity of five wild mushroom extracts to potentiate the action of standard antibiotics, through synergisms that allow a decrease in their therapeutic doses and ultimately contribute to the reduction of resistances.The authors are grateful to Portuguese Foundation for Science and Technology (FCT) and COMPETE/QREN/EU for the financial support through the research project PTDC/AGR-ALI/110062/2009, and to CHTMAD – Hospital Center of Trás-os-Montes e Alto Douro and Siemens for all the supportinfo:eu-repo/semantics/publishedVersio

Nutritional and biochemical profiling of Leucopaxillus candidus (Bres.) singer wild mushroom

The wild mushroom Leucopaxillus candidus (Bres.) Singer was studied for the first time to obtain information about its chemical composition, nutritional value and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. candidus methanolic extract was tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). L. candidus was shown to be an interesting species in terms of nutritional value, with high content in proteins and carbohydrates, but low fat levels, with the prevalence of polyunsaturated fatty acids. Mannitol was the most abundant free sugar and β-tocopherol was the main tocopherol isoform. Other compounds detected were oxalic and fumaric acids, p-hydroxybenzoic and cinnamic acids. The methanolic extract revealed antioxidant activity and did not show hepatoxicity in porcine liver primary cells. The present study provides new information about L. candidus.The authors are grateful to Foundation for Science and Technology (FTC, Portugal) for financial support to CIMO (Pest-OE/AGR/UI0690/2014) and L. Barros (SFRH/BPD/107855/2015) grant

Composição química e valor nutricional de cogumelos silvestres comestíveis do nordeste de Portugal

Neste trabalho, determinou-se a composição química e o valor nutricional de cinco espécies de cogumelos silvestres comestíveis (Agaricus arvensis, Lactarius deliciosus, Leucopaxillus giganteus, Sarcodon imbricatus, Tricholoma portentosum) vulgarmente consumidos na região de Trás-os-Montes, Nordeste de Portugal. A avaliação da composição química incluíu determinação de humidade, gordura total, proteína total, cinzas, hidratos de carbono e do valor nutricional. O perfil de macronutrientes revelou genericamente que os cogumelos silvestres são fontes ricas em proteínas e hidratos de carbono, e que contêm quantidades reduzidas de gordura. A análise da composição em ácidos gordos, realizada por cromatografia gás-líquido acoplada a um detector de ionização de chama (GC/FID), permitiu a quantificação de quinze ácidos gordos. Os ácidos gordos insaturados e, em particular, os ácidos oleico e linoleico, são os mais abundantes. Determinou-se também a composição em açucares individuais por cromatografia líquida de alta resolução acoplada a um detector de índice de refracção (HPLC/RI), sendo o manitol e a trealose os açucares mais abundantes

Chemical characterization and bioactive properties of portuguese wild edible mushrooms

Nineteen different mushroom species (Agaricus arvensis, Agaricus bisporus, Agaricusromagnesii, Agaricus silvaticus, Agaricus silvicola, Cantharellus cibarius, Hypholomafasciculare, Lactarius deliciosus, Lactarius piperatus, Lepista nuda, Leucopaxillusgiganteus, Lycoperdon molle, Lycoperdon perlatum, Macrolepiota mastoidea,Macrolepiota procera, Ramaria botrytis, Sarcodon imbricatus, Tricholoma acerbum and Tricholoma portentosum) from Northeast of Portugal, one of the European regions with higher wild edible mushrooms diversity, were evaluated for their chemical composition, nutritional value and bioactive properties (antioxidant and antimicrobial activities), in order to valorise mushrooms as a source of nutrients and nutraceuticals.The analysis of nutrients included determination of proteins, fats, ash, and carbohydrates, particularly sugars by HPLC-RI. The analysis of nutraceuticals included determination of fatty acids by GC-FID, and other phytochemicals such as tocopherols, by HPLC-fluorescence, phenolic compounds by HPLC-DAD-ESI/MS, carotenoids and ascorbic acid, by spectrophotometric techniques. The antioxidant activity was screened through chemical and biochemical assays. The chemical assays allowed an evaluation of their reducing power, radical scavenging activity and inhibition of -carotene bleaching, while biochemical assays evaluated the lipid peroxidation inhibition capacity, using erythrocytes and brain cells as models. The antimicrobial activity was evaluated using clinical isolates or collection microorganisms (Gram positive and Gram negative bacteria and fungi).The macronutrient profile in general revealed that the wild mushrooms were rich sources of protein and carbohydrates and had low amounts of fat. The analysis of fatty acid composition allowed the quantification of twenty three fatty acids. Unsaturated fatty acids and, in particular, oleic and linoleic acids, were predominant. Mannitol and trehalose were the most abundant sugars. The analysed mushrooms also contain very useful phytochemicals such as phenolic compounds, tocopherols, ascorbic acid, and carotenoids. Particularly, four phenolic acids (protocatechuic, p-hydroxybenzoic acid, pcoumaric and cinnamic acid) and two vanillic acid isomers were detected, identified and quantified, as also three of the tocopherols vitamers (F-, G-, H- tocopherol); no tocotrienols were detected. All the species proved to have antioxidant properties,namely radical scavenging activity and lipid peroxidation inhibition capacity. Ramaria botrytis was the most efficient species presenting the lowest EC50 values in the chemical and biochemical assays, which can be related to their higher content in bioactive compounds. The majority of the species revealed antimicrobial activity selectively against Gram + bacteria, in some cases, with lower minimum inhibitory concentration than the standards.Processing and cooking practices had a determining influence on chemical compositionand antioxidant properties. Cooked samples showed lower nutrients concentrations andlower antioxidant activity than either dried or frozen samples. Nevertheless, for fatty acids and sugar individual profiles, only cooking procedures seemed to be relevant, the cooked samples presenting higher MUFA, and lower PUFA and sugars contents. The fruiting body maturity stage proved to have influence on chemical composition and bioactivity of the wild mushrooms; mature carpophorus with mature spores is notrecommended for nutritional and medicinal proposals.In addition to dried mushrooms, alternative or substitute mushroom products are mycelia that could also be used as food and food-flavouring material, or in the formulation of nutraceuticals and functional foods. In order to explore it, mycelium of Leucopaxillus giganteus was produced using different pH, carbon and nitrogen sourcesin the culture medium, and evaluated for their bioactive properties. The antioxidantsconcentration increased along the growth time as a response to the oxidative stress andsubsequent free radicals production. The aldohexose glucose and diammoniumphosphate proved to be the most appropriate carbon and nitrogen sources to increaseantioxidant activity, leading to the highest phenols content and lowest EC50 values.Public health authorities consider prevention and treatment with nutraceuticals/phytochemicals a powerful instrument in maintaining and promotinghealth, longevity and life quality. The beneficial effects of nutraceuticals will undoubtedly have an impact on nutritional therapy; they also represent a growing segment of today s food industry. Mushrooms might be used directly in diet and promote health, taking advantage of the additive and synergistic effects of all the bioactive compounds present. Therefore, the ongoing research will lead to a new generation of foods, and will certainly promote their nutritional and medicinal use.Diecinueve especies diferentes de setas silvestres (Agaricus arvensis, Agaricus bisporus, Agaricus romagnesii, Agaricus silvaticus, Agaricus silvicola, Cantharellus cibarius, Hypholoma fasciculare, Lactarius deliciosus, Lactarius piperatus, Lepistanuda, Leucopaxillus giganteus, Lycoperdon molle, Lycoperdon perlatum, Macrolepiota mastoidea, Macrolepiota procera, Ramaria botrytis, Sarcodon imbricatus, Tricholoma acerbum and Tricholoma portentosum) del Nordeste de Portugal, una de las regiones europeas con mayor diversidad hongos silvestres comestibles, fueron evaluados conrelación a su composición química, valor nutritivo y propiedades bioactivas (actividades antioxidante y antimicrobiana), con vistas a su valorización como fuente de nutrientes y nutracéuticos.El análisis de nutrientes incluyó la determinación de proteínas, grasas, cenizas, hidratos de carbono, y particularmente azúcares por HPLC-RI. El análisis de nutracéuticos incluyó la determinación de ácidos grasos por GC-FID y otros fitoquímicos, como tocoferoles por HPLC-fluorescencia, compuestos fenólicos por HPLC-DAD-ESI/MS,carotenoides y ácido ascórbico por espectrofotometría. La actividad antioxidante sevaloró mediante ensayos químicos y bioquímicos. Los ensayos químicos consistieron en la evaluación del poder reductor, inhibición del radical libre DPPH e inhibición de la decoloración del G-caroteno, mientras que los ensayos bioquímicos evaluaron la capacidad de inhibición de la peroxidación lipídica, utilizando como modelos eritrocitos y células del cerebro. La actividad antimicrobiana fue evaluada utilizando aislados clínicos y microorganismos de colección (bacterias Gram positivas y Gram negativas yhongos).El perfil de macronutrientes reveló que, en general, los hongos silvestres son fuentes ricas de proteínas e hidratos de carbono y que poseen poca cantidad de grasa. El análisis de la composición de ácidos grasos permitió la cuantificación de veintitrés ácidos grasos. Los ácidos grasos insaturados y, en particular, los ácidos oleico y linoleico, eran predominantes. Manitol y trehalosa fueron los azúcares más abundantes. Las setas analizadas también contienen fitoquímicos tales como compuestos fenólicos, tocoferoles, ácido ascórbico y carotenoides. En particular, fueron detectados,identificados y cuantificados cuatro ácidos fenólicos (ácidos protocatéquico, phidroxibenzoico,p-cumárico y cinámico) y dos isómeros del ácido vanílico y tambiéntres isómeros de tocoferoles (F, G, de H-tocoferol), mientras que no se detectarontocotrienoles. Todas las especies mostraron propiedades antioxidantes, especialmentecapacidad para inhibir radicales libres y la peroxidación lipídica. Ramaria botrytis fue laespecie más eficiente en este sentido, presentando los valores más bajos de EC50 en los ensayos químicos y bioquímicos, lo que puede estar relacionado con su mayor contenido en compuestos bioactivos. La mayoría de las especies mostraron actividad antimicrobiana selectiva contra las bacterias Gram positivas, en algunos casos, con concentraciones mínimas inhibitorias menores que las de los compuestos usados como referencia.El procesado y las prácticas culinarias ejercen una influencia determinante en la composición química y propiedades antioxidantes de las setas estudiadas. Las muestras cocinadas tenían menor concentración de nutrientes y menor actividad antioxidante que las muestras secas o congeladas. Sin embargo, los perfiles individuales de ácidos grasos y azúcares sólo se vieron afectados en las muestras cocinadas, las cuales presentaban niveles mayores de ácidos grasos monoinsaturados e inferiores de poliinsaturados y de azúcares.La maduración del cuerpo fructificante también demostró tener influencia en la composición química y en la bioactividad de las setas silvestres; así, los carpóforos maduros con esporas maduras no pueden ser recomendados nutricional nimedicinalmente.Un producto alternativo a las setas desecadas son los micelios, que también podrían ser utilizados como alimento o ingrediente, o en la formulación de nutracéuticos y alimentos funcionales. Para explorar esta posibilidad, se obtuvieron micelios de Leucopaxillus giganteus utilizando diferentes pH, fuentes de carbono y nitrógeno en elmedio de cultivo, y posteriormente se evaluaron sus propiedades bioactivas. La concentración de antioxidantes aumentó a lo largo del tiempo decrecimiento como respuesta al estrés oxidativo y, por tanto, la producción de radicales libres. Laaldohexosa glucosa y el fosfato diamónico demostraron ser respectivamente las fuentesde carbono y de nitrógeno más apropiadas para aumentar la actividad antioxidante,dando lugar al más alto contenido de compuestos fenólicos y valores más bajos de EC50.El empleo de nutracéuticos/fitoquímicos puede ser un instrumento eficaz en el mantenimiento y la promoción de la salud, longevidad y calidad de vida. Los efectos beneficiosos de nutracéuticos, sin duda, no sólo tienen un impacto en la terapianutricional, sino que también representan un segmento creciente de la actual industria alimentaria. En este sector podrían ubicarse las setas, cuyo empleo como parte de la dieta con fines de promoción de la salud podría ser tenido en cuenta a la vista de la variedad de compuestos bioactivos que contienen y los posibles efectos aditivos o sinérgicos que pueden existir entre ellos. La investigación en curso trata de explorar estaalternativa para, en definitiva, promover nuevas generaciones de alimentos con un valorañadido basado en sus propiedades nutritivas y medicinales