1,433 research outputs found

    Uticaj ekstrakata izolovanih iz gljive Ganoderma lucidum na neke mikroorganizme

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    Ganoderma lucidum (Leyss.: Fr) Karst, a mushroom-like fungus is one of the most famous traditional Chinese medicinal herbs. It received wide popularity as a healthy food and medicine in the Far East for more than 2000 years because of its high medicinal value. One of very interesting aspects of G. lucidum's performance is antimicrobial effect due to the extracts derived from this mushroom, which contain bacteriolitic enzyme, lysozyme and acid protease. The effects of these extracts depend on their composition extraction mode and refining. Bioactive components isolated from several G. lucidum's strains showed different effects on the investigated microorganisms. In some cases, the influence was very intensive, with inhibitory or stimulating effect, while some of them did not show any influence on the investigated microorganisms.Ganoderma lucidum (Leyss.: Fr) Karst je jedna od najvažnijih tradicionalnih kineskih gljiva. Prema pisanim podacima starim više od 2000 godina koristi se na Dalekom istoku kao zdrava hrana i lekovita gljiva. Jedan od vrlo interesantnih aspekata korišćenja gljive Ganoderma lucidum je i upotreba ove gljive kao antimikrobnog sredstva, zahvaljujući izolovanim ekstraktima koji sadrže bakteriolitičke enzime, lizozime i kisele proteaze. Efekti ovih ekstrakata zavise od njihovog sastava, načina ekstrakcije i prečišćavanja. Bioaktivne komponente izolovane iz nekoliko sojeva gljive Ganoderma lucidum pokazale su različite efekte na ispitivane mikroorganizme. U nekim slučajevima uticaj ekstrakata je bio vrlo intenzivan, inhibišući ili stimulišući, dok neki od njih nisu pokazali nikakav uticaj na ispitivane mikroorganizme

    Antioksidativne aktivnosti vrelih vodenih ekstrakata iz karpofora i spora gljive Ganoderma lucidum

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    Ganoderma lucidum (Leyss.:Fr.) Karst is one of the medicinal mushrooms, which possesses enviable antioxidant properties. Objective of this investigation was to evaluate antioxidant activity, reducing power, scavenging abilities on 1.1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelating effects on ferrous ions of hot water extracts obtained from carpophore and spores of this mushroom. Hot water extract from carpophore (Gl-I) showed high antioxidant activity of 85.7 ± 0.7%, at 10 mg/ml, while antioxidant activity of hot water extract from spores (Gl-Is) was 9.2 ± 0.3% at 10 mg/ml. Reducing power of Gl-I reached a plateau of 3.4 ± 0.1 at 20 mg/ml, and 0.3 ± 0.0 at 20 mg/ml for Gl-Is. At 10 mg/ml, scavenging ability on DPPH radicals of Gl-I increased to 96.8 ± 2.5%, whereas Gl-Is scavenged DPPH radicals by 69.6 ± 2.5% at 10 mg/ml. Gl-I chelated 81.6 ± 3.6 % of ferrous ions at 20 mg/ml, while the chelating effect of Gl-Is was 73.8 ± 1.7%. The antioxidative activities of hot water extracts from carpophore and spores of the mushroom G. lucidum were concentration dependent and increased with an increase in the concentration.Ganoderma lucidum (Leyss.: Fr.) Karst je jedna od medicinski važnih gljiva, koja poseduje izuzetna antioksidativna svojstva. Cilj ovog istraživanja bio je potvrda antioksidativne aktivnosti, redukcione sposobnosti, mogućnosti hvatanja 1,1-difenil-2-pikrilhidrazil (DPPH) radikala i sposobnosti heliranja jona gvožđa vrelih vodenih ekstrakata dobijenih iz karpofora i spora ove gljive. Vreli vodeni ekstrakt iz karpofora (Gl-I) pokazao je visoku antioksidativnu aktivnost 85.7 ± 0.7%, pri 10 mg/ml, dok je antioksidativna aktivnost vrelog vodenog ekstrakta spora (Gl-Is) bila 9.2 ± 0.3% pri 10 mg/ml. Redukciona sposobnost ekstrakta Gl-I dostigla je nivo 3.4 ± 0.1 pri 20 mg/ml i 0.3 ± 0.0 pri 20 mg/ml za ekstrakt Gl-Is. Pri koncentraciji 10 mg/ml sposobnost hvatanja DPPH radikala ekstrakta Gl-I dostigla je 96.8 ± 2.5%, dok je ekstrakt Gl-Is vezao 69.6 ± 2.5% DPPH radikala pri 10 mg/ml. Ekstrakt Gl-I helirao je 81.6 ± 3.6 % fero jona pri koncentraciji 20 mg/ml, a helirajući efekat ekstrakta Gl-Is bio je 73.8 ± 1.7%. Antioksidativne aktivnosti vrelih vodenih ekstrakata iz karpofora i spora gljive G. lucidum zavisile su od koncentracije i povećavale su se sa povećanjem koncentracije

    Ekstrakt šumskog soja gljive Ganoderma lucidum kao prirodni antioksidant

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    Recently, much attention has been paid to revealing natural biomaterials for clinical purposes since use of synthetic antioxidants is restricted due to their carcinogenicity. Among various natural antioxidants, polysaccharides, in general, have strong antioxidant activities and can be explored as novel potential antioxidants. The aim of this work was to examine the antioxidant properties of hot water extracted polysaccharides from Ganoderma lucidum in the form of mature fruit bodies, collected from the Bojčinska forest near Belgrade, the Republic of Serbia. Antioxidant properties were assayed in vitro, by the conjugated diene method, reducing power, scavenging abilities against 1.1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelating ability on ferrous ions. At concentrations of 1 mg/ml, the scavenging ability of G. lucidum polysaccharide extract on DPPH radicals was 74.7 %. At 1 mg/ml, the radical scavenging ability of the positive controls BHT, ascorbic acid and α-tocopherol were 11.5, 77.1 and 79.4 %, respectively. The antioxidant activity of the polysaccharide extract increased as the concentration increased to 78.0% at 20 mg/ml. Antioxidant activities of ascorbic acid and α-tocopherol were 63.8 % and 65.4% at 20 mg/ml. Polysaccharide extract from G. lucidum showed steady increase in the reducing activity as concentrations increased to 2.9 at 20 mg/ml. Ascorbic acid, used as a positive control, had a reducing power of 3.9 at 5 mg/ml. Chelating effects of the polysaccharide extract on ferrous ion increased with the increased concentrations. At 0.1-20 mg/ml, the chelating ability of G. lucidum polysaccharide extract was between 10.3-87.8%. The chelating effect of the synthetic metal chelator EDTA was 100% at 0.1-20 mg/ml, while citric acid did not prove to be good chelating agent for ferrous ions in this assay since its chelating ability was 10.3% at 20 mg/ml.U današnje vreme sve veće pažnja se poklanja pronalaženju prirodnih bioloških materijala koji imaju antioksidativna svojstava. Neželjeni efekti, oštećenje jetre i karcinogeneza, od strane sintetičkih antioksidanata koji se koriste kao aditivi ishrani su uveliko potvrđeni. Među različitim pri rodnim antioksidantima polisaharidi privlače sve veću pažnju kao jedinjenja sa izraženom antioksidativnom aktivnošću. Cilj rada je bio da se ispitaju antioksidativna svojstva vrelog vodenog ekstrakta polisaharida gljive Ganoderma lucidum dobijenog iz zrelih plodonosnih tela, prikupljenih u Bojčinskoj šumi u blizini Beograda, Republika Srbija. Antioksidativna svojstva su ispitivana pomoću antioksidativne metode u model sistemu linoleinske kiseline, merenjem snage redukcije, sposobnosti hvatanja 1,1-difenil-2-pikrilhidrazil (DPPH) radikala i sposobnosti heliranja jona gvožđa. Pri koncentraciji od 1 mg/ml sposobnost hvatanja DPPH radikala polisaharidnog ekstrakta šumskog soja Ganoderma lucidum dostigla je nivo od 74.7%, dok su izmerene vrednosti, pri istoj koncentraciji, za pozitivne kontrole BHT, askorbinsku kiselinu i α-tokoferol iznosile 11.5, 77.1 i 79.4%. Antioksidativna aktivnost izmerena u model sistemu linoleinske kiseline zavisila je od koncentracije i povećavala se sa povećanjem koncentracije. Izmerena je vrednost od 78.0% pri koncentraciji od 20 mg/ml. Antioksidativne aktivnosti askorbinske kiseline i α-tokoferola pri koncentraciji od 20 mg/ml bile su 63.8 i 65.4%. Redukciona sposobnost polisaharidnog ekstrakta dostigla je nivo od 2.9 pri 20 mg/ml i 3.9 pri 5 mg/ml kod askorbinske kiseline koja je korišćena kao pozitivna kontrola. Sposobnost heliranja jona gvožđa se povećavala sa povećanjem koncentracije. Pri koncentraciji od 0.1-20 mg/ml izmerena sposobnost heliranja bila je između 10.3-87.8%. Helatni efekat EDTA bio je 100% u opsegu od 0.1-20 mg/ml. Limunska kiselina se nije pokazala kao dobar helirajući agens (10.3% pri 20 mg/ml)

    Uticaj strukturnih karakteristika na imunostimulativnu aktivnost glukana ekstrahovanih iz gljive Agaricus blazei

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    High molecular weight b-D-glucans derived from Basidiomycetes cell walls are able to specifically activate cellular and humoral components of the host immune system. The aim of this paper was to examine immunomodulating activity of native, chemically and enzimatically modified glucans from Agaricus blazei mushroom and to determine which structural features are of primary importance for their stimulation referring to humane immune cells. The immunomodulating activities were tested in vitro, by stimulation of peripheral blood mononuclear cells (PBMCs) and measuring of interferon-gamma (IFN-g) production by enzyme linked immunosorbent assay (ELISA). Measurements of immunomodulatory capacity of Agaricus blazei native glucans showed their expressive immunostimulating effect on activated PBMCs and synthesis of IFN-g. The results obtained after the stimulation of cells with 1M H2SO4 and 1M NaOH, the treated glucans showed that primary structure is of more importance than the tertiary structure of the triple helix for their immunostimulating activity and synthesis of IFN-g. Glucans of lower molecular weight obtained after acid hydrolysis appeared as effective immunostimulators of PBMC's. The results obtained after the incubation of cells with 1,6 b-glucanase modified glucans suggest that b-(1,6) binding of glucose monomers probably has no importance for the production of imunostimulating effects, in vitro. This confirmed that b-(1,3) bonds are the primary determinants of immunomodulatory activities and stimulation of IFN-g synthesis.b-D-glukani velikih molekulskih masa izolovani iz ćelijskog zida gljiva iz klase Basidiomycetes imaju sposobnost da specifično aktiviraju celularne i humoralne komponente imunog sistema domaćina. Imunomodulatorska aktivnost miko-D-glukana u funkciji je njihovih hemijskih karakteristika, kao što su molekulska masa, stepen grananja, rastvorljivost u vodi i tercijarna struktura. Cilj ovog rada je bio ispitivanje imunomodulatorske aktivnosti nativnih, hemijski i enzimski modifikovanih glukana gljive Agaricus blazei i da se utvrdi koja je strukturna karakteristika od primarnog značaja za stimulaciju ćelija humanog imunog sistema. Imunomodulatorska aktivnost je testirana in vitro, stimulacijom mononuklearnih ćelija krvi iz perifernog krvotoka (PBMC) molekulima glukana i merenjem količine sintetisanog interferona-gama (IFN-g) od strane stimulisanih ćelija enzimoimunotestom (ELISA). Merenjem imunomodulatorskog kapaciteta Agaricus blazei nativnih glukana pokazano je da ovi molekuli imaju izraženo imunostimulativno dejstvo na aktivirane PBMC ćelije i stimulaciju sinteze IFN-g. Stimulacijom ćelija glukanima koji su prethodno bili parcijalno hidrolizovani 1M H2SO4 i 1M NaOH izmereni titar IFN-g se nije značajno promenio u odnosu na nativne molekule. Glukani manjih molekulskih masa, nastali nakon kisele hidrolize, pokazali su se kao efikasni stimulatori PBMC ćelija. Merenjem titra IFN-g nastalog nakon inkubacije aktiviranih ćelija sa 1,6 b-glukanazama modifikovanim glukanima potvrđeno je da su fragmenti b-(1,3)-glukana velikih molekulskih masa (MM > 80 kDa) i mali fragmenti b-(1,3)-glukana (MM lt 80 kDa), nastali nakon enzimske modifikacije, ispoljili značajno povećanje imunostimulativne aktivnosti u odnosu na nativne molekule. Dobijeni rezultati su ukazali da b-(1,6)-glikozidne veze nemaju značaja u ispoljavanju imunostimulativnog efekta, in vitro. Ovim je potvrđeno da je za imunostimulativnu aktivnost i stimulaciju sinteze IFN-g od primarnog značaja prisustvo b-(1,3)-glikozidnih veza. Zaključeno je da je za imunomodulatorsku aktivnost ovih molekula bitna primarna struktura, a ne konformacija trostrukog heliksa nativnih molekula, kao i da su molekuli glukana manjih molekulskih masa efikasni stimulatori sinteze IFN-γ

    Application of chitosan films in the quality control of fresh shredded vegetables

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    The objective of this study was to investigate the antimicrobial effects of chitosan gelatin films with or without added essential oils against Listeria monocytogenes on fresh shredded cabbage, carrot and black radish. Samples of fresh shredded vegetables were inoculated with L. monocytogenes and then stored between two layers of edible chitosan films at various concentrations, with or without added essential oils. The inoculated, film treated samples were stored at 4 °C. Samples were taken every day,during six days, for enumeration of surviving L. monocytogenes by plating on appropriate media. Compared to control,1% chitosan film and 0.5% film-induced to 4.7 and 2.9 log CFU/g reductions on shredded cabbage 3rd day respectively. After 3 days, films with 1% chitosan reduced L. monocytogenes population by 3 log CFU/g on carrots. Antimicrobial activity of chitosan film increases with increasing concentrations of applied chitosan, where 1% chitosan film has the highest antimicrobial activity compared to 0.5% chitosan film. Nevertheless, chitosan films were more effective on black radish than on cabbage and carrot. Addition of thyme essential oils, significantly improves the activity of the antimicrobial film and reduce the time required for the inhibition of bacteria in vegetables. Also, changes of color, taste, aroma and chemical composition of non-treated and treated samples were determined. The application of chitosan films exerts a significant influence on the pH changes and content of soluble solids of stored vegetables. Chitosan films improved sample appearance, since they diminished the occurrence of the color changes during storage. The results of this experiment showed that the use of chitosan films is a viable alternative in controlling the microorganisms present in minimally processed vegetables, improving its sensory quality. The advantages of edible films were the simple manufacturing process, biodegradability and usage of natural and safe compounds

    Antimicrobial Activity of Chitosan Films With Essential Oils Against Listeria monocytogenes on Cabbage

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    BACKGROUND: The highest incidence of listeriosis, due to consumption of ready-to-eat foods and fresh, shredded, minimally processed vegetables, occurs among pregnant women and the elderly. In order to reduce the prevalence of listeriosis among consumers, better protective measures are recommended. Chitosan films, with or without added essential oils, represent a modern, safe method of preserving the quality of such vegetables and significantly reducing the incidence of Listeria monocytogenes in these foods. Objectives: The present study was conducted to evaluate the antimicrobial properties of composite chitosan-gelatin films with and without essential oils against two strains of L. monocytogenes, ATCC 19115 and ATCC 19112, in fresh shredded cabbage. Methods: Shredded cabbage was inoculated with L. monocytogenes and packed between two layers of the chitosan composite film, then placed in Petri dishes. The prepared samples were stored at 4 degrees C then analyzed for total viable count on PALCAM agar while incubated at 37 degrees C, every 24 hours for 7 days. Results: Average L. monocytogenes content ranged from 4.2 - 5.4 log CFU/g, reaching values of 7.2 - 8.6 log CFU/g in samples of untreated cabbage. A complete reduction of L. monocytogenes ATCC 19115 on cabbage was achieved after 120 hours in the presence of 0.5% chitosan film, whereas reduction of L. monocytogenes ATCC 19112 was achieved after 144 hours. In the presence of 1% chitosan film, the bacteria withered more quickly and complete reduction of both species of L. monocytogenes was achieved after 96 hours. Conclusions: All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of both strains of L. monocytogenes on cabbage. The best effect was achieved with a 1% chitosan concentration. The addition of essential oils increased the antimicrobial activity of all tested films

    Crystal structure of a murine α-class glutathione S-transferase involved in cellular defense against oxidative stress

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    Glutathione S-transferases (GSTs) are ubiquitous multifunctional enzymes which play a key role in cellular detoxification. The enzymes protect the cells against toxicants by conjugating them to glutathione. Recently, a novel subgroup of α-class GSTs has been identified with altered substrate specificity which is particularly important for cellular defense against oxidative stress. Here, we report the crystal structure of murine GSTA4-4, which is the first structure of a prototypical member of this subgroup. The structure was solved by molecular replacement and refined to 2.9 Å resolution. It resembles the structure of other members of the GST superfamily, but reveals a distinct substrate binding site.

    Antimicrobial activity of chitosan coatings and films against Listeria monocytogenes on black radish

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    AbstractThe antibacterial activity of chitosan coatings prepared with acetic or lactic acid, as well as of composite chitosan–gelatin films prepared with essential oils, was evaluated in fresh shredded black radish samples inoculated with Listeria monocytogenes ATCC 19115 and L. monocytogenes ATCC 19112 during seven days of storage at 4°C. The chitosan coating prepared with acetic acid showed the most effective antibacterial activity. All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of L. monocytogenes on black radish, although a higher inhibition of pathogens was achieved at higher concentrations of chitosan. The antimicrobial effect of chitosan films was even more pronounced with the addition of essential oils. Chitosan–gelatin films with thyme essential oils showed the most effective antimicrobial activity. A reduction of 2.4log10CFU/g for L. monocytogenes ATCC 19115 and 2.1log10CFU/g for L. monocytogenes ATCC 19112 was achieved in the presence of 1% chitosan film containing 0.2% of thyme essential oil after 24h of storage
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