Antifungal Activity

The polyene macrolide antibiotic nystatin produced by Streptomyces noursei contains a deoxyaminosugar mycosamine moiety attached to the C-19 carbon of the macrolactone ring through the β-glycosidic bond. The nystatin biosynthetic gene cluster contains three genes, nysDI, nysDII , and nysDIII , encoding enzymes with presumed roles in mycosamine biosynthesis and attachment as glycosyltransferase, aminotransferase, and GDP-mannose dehydratase, respectively. In the present study, the functions of these three genes were analyzed. The recombinant NysDIII protein was expressed in Escherichia coli and purified, and its in vitro GDP-mannose dehydratase activity was demonstrated. The nysDI and nysDII genes were inactivated individually in S. noursei , and analyses of the resulting mutants showed that both genes produced nystatinolide and 10-deoxynystatinolide as major products. Expression of the nysDI and nysDII genes in trans in the respective mutants partially restored nystatin biosynthesis...

The substituted pterocarpenes named aracarpene-1 (1) and aracarpene-2 (2) were isolated from wounded peanut seeds challenged by a strain of Aspergillus caelatus. The structures of these putative phytoalexins were determined by interpretation of NMR and MS data. The aracarpenes were investigated for their antifungal and antibacterial activities as well as antioxidant, anti-inflammatory, and cytotoxic activities in mammalian cells. Aracarpene-2 demonstrated high antibacterial properties against tested gram-positive and gram-negative bacteria, whereas aracarpene-1 displayed low antibacterial properties against the same bacteria. Both compounds had no antifungal activity against Aspergillus flavus. Together with peanut stilbenoids that are also produced in the challenged seeds, these compounds may represent a class of low-molecular weight peanut metabolites with a defensive role(s) against pathogenic microorganisms.

The essential oil of Achillea atrata L. and its major component, 1,8-cineole, were evaluated for their antifungal activity by the mycelial growth method against 18 micromycetes (Alternaria alternata, Aspergillus niger, A. ochraceus, A. versicolor, A. flavus, A. terreus, Cladosporium cladosporioides, Fusarium tricinctum, Penicillium ochrochloron, P. funiculosum, Phomopsis helianthi, Trichoderma viride, Trichophyton mentagrophytes, T. rubrum, T. tonsurans, Epidermophyton floccosum, Microsporum canis,

Mucormycosis is considered one of the most dangerous invasive fungal diseases. In this study, a facile, green and eco-friendly method was used to biosynthesize silver nanoparticles (AgNPs) using Pseudomonas indica S. Azhar, to combat fungi causing mucormycosis. The biosynthesis of AgNPs was validated by a progressive shift in the color of P. indica filtrate from colorless to brown, as well as the identification of a distinctive absorption peak at 420 nm using UV-vis spectroscopy. Fourier-transform infrared spectroscopy (FTIR) results indicated the existence of bioactive chemicals that are responsible for AgNP production. AgNPs with particle sizes ranging from 2.4 to 53.5 nm were discovered using transmission electron microscopy (TEM). Pattern peaks corresponding to the 111, 200, 220, 311, and 222 planes, which corresponded to face-centered cubic forms of metallic silver, were also discovered using X-ray diffraction (XRD). Moreover, antifungal activity measurements of biosynthesized ...

Objective Melon charcoal rot is one of the most important diseases that significantly reduces the yield of melon (Cucumis melo L.). The main objectives of this study were: isolation of actinomycetes from the rhizospheric soil of different melon cultivation regions located in the Kerman and Sistan and Baluchestan provinces of Iran; investigating the antagonistic effects of actinomycetes against melon black stem or charcoal rot disease; evaluation of siderophore production by isolates in vitro; identification of potential isolate by PCR, and investigating their biocontrol efficacy against Macrophomina phaseolina in melon under greenhouse condition. Materials and methods Eighty actinomycete isolates were isolated from the soil of selected different melon cultivation areas and their antifungal activity against Macrophomina phaseolina was investigated. Potential isolates were evaluated for biological activities. Moreover, the efficacy of selected actinobacteria in order to biocontrol cha...

Candidiasis is a common opportunistic fungal infection that responds well to amphotericin B (AMPH) treatment. However, AMPH often causes adverse effects such as kidney injury and hypokalemia. Because some essential oils have been reported to have antifungal effects, ...

A row of 1-alkyne (C6-C17) derivatives against tetrahydroisoquinoline have been synthesized. 1alkyne (C6-C17) derivatives cytotoxicity against three lines of cancer cells and two lines of normal cells was studied. It was found that 1-tridecyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline exhibits a high cytotoxic effect with low toxicity to healthy cells. Antimicrobial activity of 1-alkyne (C6-C17) derivatives against 5 strains of bacteria and fungus was studied. It has been found that 1-nonyl-6,7dimethoxy-1,3,4-tetrahydroisoquinoline exhibits strong antibacterial and antifungal effects.

Introduction: There are many reports on the application of medicinal plants in traditional medicine, as well as numerous applications of metallic nanoparticles in different biomedical fields. Plant extract mediated green synthesis of nanoparticles and investigations on their therapeutic effects are new concepts. The medicinal plant of Cuminum cyminum L. includes a wide range of secondary metabolites with a high reducing power, which can be used for green biosynthesis of silver nanoparticles. The main aims of this study were phytochemical analysis of seed aqueous extract of Cuminum cyminum, biosynthesis of silver nanoparticles using this extract, the achievement of optimization condition for the synthesis of silver nanoparticles, and assessment of biological activaties of both the extract and the synthesized nanoparticles.

Materials & Methods: Total phenol and flavonoid, reducing sugar, starch, and ascorbic acid contents were measured by Folin-Ciocalteo, aluminum chloride, dinitrosalicylic acid, anthrone, and dinitrophenyl hydrazine reagents, respectively. The Ag+ ions reduction and characterization of silver nanoparticles were assessed by UV-Visible spectrophotometry, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Antioxidant activity of the samples was screened by DPPH free radical scavenging. Antibacterial activity of the samples was also evaluated against four gram-positive and -negative bacteria namely, Bacillus cereus (PTCC 1247), Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 35218), and Pseudomonas aeruginosa (ATCC 27853) by disc diffusion method. In addition, antifungal activity was assessed against Fusarium oxysporum.

Findings: The indings indicated that the seed extract contained the high amounts of total phenolic and flavonoidic compositions, as well as sugar, starch, and ascorbic acid. Different analyses showed that the mean size of the synthesized nanoparticles was 5-45 nm in the optimal condition. The samples had proper antioxidant potential (IC50=1.35-1.67 mg/ml) and the extract in combination with silver nanoparticles represented synergistic effect in DPPH free radical scavenging (IC50=1.35 mg/ml). In addition, the investiogated samples had a good antibacterial activity against some of tested bacteria and also antifungal activity against Fusarium oxysporum.

Discussion & Conclusions: It seems that the secondary metabolites of Cuminum cyminum have good potential for the reduction and stabilization of the synthesized Ag nanoparticles. Both the seed extract and synthesized nanoparticles using this extract have considerable biological activities and may be used in antioxidant nutrient production or medicinal supplements in future.

The morphology and distribution of the glandular trichomes of Vitex ferruginea Schumach. et Thonn. subsp. amboniensis (Gürke) Verdc. from Mozambique were investigated as well as the chemical composition and the antifungal activity of its essential oil. Scanning electron ...

In this study, the inhibitory properties of some essential oils including citrus (Citrus sinensis L. Osbeck), laurel (Laurus nobilis L.), myrtle (Myrtus communis L.), oregano (Origanum vulgare L.), and savory (Satureja thymbra L.) were investigated against the heat resistant molds Aspergillus fumigatus and Paecilomyces variotii isolated from margarine in a previous study in order to assess the potential for using these essential oils as a natural food preservative. In this study, the essential oils of the plants were obtained by steam distillation using Clevenger apparatus and were tested for antifungal activities at 0.25, 0.50, and 1.00% concentrations. Inhibitory effects of the essential oils on the growth of the fungi followed the sequence: oregano=citrus>savory>laurel>myrtle. P. variotii was more resistant against the essential oils than A. fumigatus.

The antifungal activity of ether extract of Nigella sativa seed and its active principle thymoquinone was tested against eight species of dermatophytes: four species of Trichophyton rubrum and one each of Trichophyton interdigitale, Trichophyton mentagrophytes, Epidermophyton ...

A halotolerant bacterium capable of chitinase production was previously isolated from saline soils of Gavkhooni marsh, Iran. The strain was identified as Bacillus pumilus strain SG2. This strain secretes two chitinases into the medium in response to the presence of ...

Background Study of in vivo antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida spp. Methods The in vitro antifungal activity of HE, BUTE, fluconazole (FLU), and itraconazole (ITRA) was determined by the broth microdilution method. We obtained values of minimal inhibitory concentration (MIC) and minimum fungicide concentration (MFC) for 46 strains of C. albicans and 10 of C. glabrata isolated from patients with vulvovaginal candidiasis (VVC). VVC was induced in hyperestrogenic Wistar rats with azole-susceptible C. albicans (SCA), azole-resistant C. albicans (RCA), and azole-resistant C. glabrata (RCG). The rats were treated intravaginally with 0.1 mL of HE or BUTE at concentrations of 1%, 2.5% and 5%; 100 μg/mL of FLU (treatment positive control); or distilled water (negative control) at 1, 24, and 48 h after induction of the infection, and the progress of VVC was monito...

Streptomyces aureofaciens CMUAc130 was isolated from the root tissue of Zingiber officinale Rosc. (Zingiberaceae). It was an antagonist of Colletotrichum musae and Fusarium oxysporum, the causative agents of anthracnose of banana and wilt of wheat, respectively. Evidence for the in vitro antibiosis of S. aureofaciens CMUAc130 was demonstrated by the zone of fungal-growth inhibition. Microscopic observations showed thickness and bulbous structures at the edges of the inhibited fungal hyphae. The culture filtrate and crude extract from this strain were all inhibitory to tested phytopathogenic fungi. The major active ingredients from the culture filtrate of S. aureofaciens CMUAc130 were purified by silica gel-column chromatography and identified to be (i) 5,7-dimethoxy-4-p-methoxylphenylcoumarin and (ii) 5,7-dimethoxy-4-phenylcoumarin by NMR and mass-spectral data, respectively. Bioassay studies showed that compounds (i) and (ii) had antifungal activities against tested fungi, and thei...

Dentre os patógenos veiculados pelas sementes e grãos do milho (Zea mays L.), Fusarium proliferatum causa tombamento e morte de plântulas, podridão de raízes, de colmo, de espiga e grãos. Assim, o tratamento de sementes mostra-se como importante medida para preservar a qualidade. O objetivo do presente trabalho foi avaliar a atividade antifúngica de diferentes concentrações dos extratos de alho (Allium sativum L.) e capim-santo (Cymbopogon citratus Stapf.) visando o controle de F. proliferatum em sementes de milho e observar os efeitos dos tratamentos sobre a germinação de sementes, sanidade e desenvolvimento das plântulas. A partir de grãos de milho, foi feito o isolamento de F. proliferatum, que foi cultivado em meio BDA. Foram avaliados os efeitos dos extratos de alho e capim santo sobre crescimento micelial, nas concentrações 0,5%, 1,0%, 2,5%, 5,0% e 10,0%, medindo-se os diâmetros das colônias do fungo durante oito dias. Esporos de F. proliferatum foram imersos em soluções dos e...

The development and extensive spread of multi-drug resistant bacteria are considered as a major public health concern. Failures to control severe infections due to antibiotic resistance have augmented healthcare costs as well as patient morbidity and mortality. Presently, natural product-based therapeutics are gaining significant attention both for their antimicrobial effectiveness and for not persuading drug resistance. Furthermore, recent developments in nanoscience on new drug delivery systems built on nanostructured materials from plants and microbes have emerged which focus on targeted delivery and controlled release of therapeutic agents. This review examines the recent investigations on the biological activities of plant and bacterial biological material for silver nanoparticle (AgNP) synthesis. Also, the underlying mechanism of antimicrobial activities of silver nanoparticles against human pathogens will be discussed. A fact of the biological activities and/or chemical responses of plants is required, not only for the discovery of new therapeutic agents, but because such evidence may be of value in disclosing new sources of already known biologically active compounds.

Antimicrobial features of acetone, methanol and aqueous extracts of lichens of Cladonia furcata, Parmelia caperata, Parmelia pertusa, Hypogymnia physodes and Umbilicaria polyphylla were investigated by two different methods at the same time. Testing of antimicrobial activities of extracts from five species of lichens was performed by disc diffusion test in relation to Gram-positive and Gram-negative bacteria and fungal organisms, and through determination of minimal inhibitory concentration (MIC) by Broth Tube Dilution method. The obtained results indicated that acetone and methanol extracts of all investigated lichens in different concentrations manifested selective antibacterial and antifungal activity. That activity was more evident in relation to Gram-positive, than Gram-negative bacteria and fungal organisms. Acetone and methanol extracts of lichens Parmelia pertusa, Hypogymnia physodes and Umbilicaria polyphylla inhibited the growth of all tested microorganisms, most of all of...