Antifungal activity of coumarins

The antifungal activity of 40 coumarins was tested against the fungal strains: Candida albicans (ATCC 14053), Aspergillus fumigatus (ATCC 16913) and Fusarium solani (ATCC 36031), using the broth microdilution method. Osthenol showed the most effective antifungal activity among all the compounds tested, with a MIC value of 125 microg/ml for Fusarium solani and 250 micro/ml for Candida albicans and Aspergillus fumigatus. The antifungal potential of this prenylated coumarin can be related to the presence of an alkyl group at C-8 position.     

Antifungal activity of some Discomycetes

The antifungal activity was investigated in culture filtrates of 131 strains (41 genera and 104 species) of Ascomycetes — Discomycetes by testing against 6 fungal species which causes diseases in man. The anti-fungal spectrum was established for a Ciboria rufo-fusca strain, the only one found to inhibit all test organisms. This strain was also active against several gram-positive and gram-negative bacteria.     

Antifungal activity of rhizospheric bacteria

Fluorescent Pseudomonad spp. were isolated from the rhizosphere of potato plants (Algeria) by serial dilutions of rhizosphere soils on Kings B medium and were tested for their antifungal activity. The antifungal activity of the Pseudomonas isolated from Potatoes rhizosphere was tested against Pythium ultimum, Rhizoctonia solani and Fusarium oxysporum in dual culture with bacteria on PDA. The Petri dish was divided into tow, on one the bacteria was spread and on the opposite side fungal plugs were inoculated and incubated for one week. Fourteen bacteria were isolated; only one isolate inhibited the growth of Pythium ultimum, Rhizoctonia solani, Fusarium solani; Fusarium oxysporum f.sp. albedinis and Fusarium oxysporum f. sp. Lycopersici with inhibition zones of 39.9, 33.7, 30.8, 19.9 and 22.5 mm respectively.     

Antifungal activity of some discomycetes

An antifungal glycoprotein compound was obtained from the culture filtrate of Ciboria rufo-fusca, by ultrafiltration and fractionation through D.E.A.E. cellulose and ultrogel Ac A34 chromatography. The purified material was homogeneous on polyacrylamide gel electrophoresis and was sensitive to the action of glucuronidase and catalase, and partly denatured by urea.The antifungal properties of the discomycete: Ciboria rufo-fusca was described in the first part of this work (6). The second part deals with the nature of the antifungal substance produced by Ciboria rufo-fusca.     

Antifungal activity of substituted aurones

Novel antifungals are in high demand as there is a growing resistance to antifungals currently in use. In particular, opportunistic fungal infections caused by Candida spp. are on the rise with infections by this genus accounting for the most severe fungal infections following chemotherapy, implantation procedures, and in patients with HIV/AIDS. A series of simple aurone analogs were synthesized and screened for antifungal activity versus Candida spp. Several compounds displayed activity at 100 μM, with two having IC₅₀ values below 20 μM for three species of Candida. One of the compounds tested here also exhibits anti-biofilm activity for mid-maturation growth.     

Antifungal activity of transferrin.

Inhibitory effects of transferrin on fungal growth were successfully estimated by measuring fungal ATP content. By this method, it was demonstrated that both human and rabbit transferrin possessed the inhibitory effect in the absence of any other factor on yeast-like and filamentous fungi. However, rabbit stimulation factor enhanced the inhibitory effect. The inhibitory effect of transferrin was nonspecific and correlated with unsaturated iron binding capacity (UIBC) of transferrin. Human transferrin was more inhibitory than rabbit transferrin.     

Antifungal activity of sesquiterpene lactones

Forty-five sesquiterpene lactones were screened for their antifungal activities against Microsporum cookei, Trichophyton mentagrophytes and Fusarium sp. The screening tests showed that a majority of sesquiterpene examined possess at least weak antifungal activity, the eudesmanolides being the most active. The antifungal activity of sesquiterpene lactones cannot be explained by the presence or absence of two potential active sites (the exocyclic methylene and, in pseudoguaianolides, a β-unsubstituted cyclopentenonel) but other functions must play a role in enhancing or reducing this activity.     

Premature cellular senescence induced by pyocyanin, a redox-active Pseudomonas aeruginosa toxin

Pseudomonas aeruginosa is an important nosocomial pathogen that can cause acute and chronic infection, particularly of the respiratory system. Pyocyanin is a major P. aeruginosa virulence factor that displays redox activity and induces oxidative stress in cellular systems. The effect of pyocyanin on replicating human pulmonary epithelial (A549) cells was investigated. Cells were exposed to pyocyanin for 24 h and their subsequent growth and development were followed for 7 days. Pyocyanin (5-10 microM) arrested cell growth and resulted in the development of a morphological phenotype consistent with cellular senescence, that is, an enlarged and flattened appearance. The senescent nature of these cells was supported by positive staining for increased lysosomal content and senescence-associated beta-galactosidase activity. All cells treated with pyocyanin (10 microM) converted to the senescent phenotype, which remained stable for up to 7 days. Exposure to pyocyanin at 25 microM or greater resulted in cell death due to apoptosis. A549 cells exposed to pyocyanin generated hydrogen peroxide in a dose-dependent manner and the senescence-inducing effect of pyocyanin was inhibited by the antioxidant, glutathione, suggesting the involvement of reactive oxygen species. The induction of premature cellular senescence by redox-active bacterial toxins may be a hitherto unrecognized aspect of infection pathology and a limiting factor in the tissue repair response to infection.     

柴胡多糖的结构和抗氧化活性分析

用超声波辅助提取法从柴胡中提取、分离得到多糖SAP3。高效液相色谱法测定其相对分子质量,红外光谱、气相色谱和原子力显微镜对其结构进行初步分析。结果表明:柴胡多糖SAP3是组分均一的多糖,由鼠李糖、木糖、甘露糖、葡萄糖、半乳糖组成,平均相对分子质量为3.3×105。红外光谱分析表明:柴胡多糖具有一般多糖类物质的特征吸收峰,单糖残基以吡喃环的形式存在。原子力显微镜显示柴胡多糖糖链具有分支结构,并缠绕形成环状结构。在0.2~1.2 mg/mL的实验浓度范围内,随着多糖质量浓度的升高,柴胡多糖SAP3对.OH的清除率逐渐增大,最大清除率可达45.2%。     

Antifungal activity of Apulia region propolis

A study was carried out to assess the in vitro antifungal activity of some natural Apulian propolis extracts of different origin. Their antifungal activity was compared to the antifungal activity of conifers and commercial propolis extracts. All extracts revealed antifungal activity against dermatophytes and Candida species. The antifungal activity differences found depended on the origin of the propolis and the solvent used for extraction. The best antifungal activity was given by the 'Orimini' propolis. The antifungal activity may have been influenced by the presence of different cinnamic and flavonoid components and their different concentration in the extracts. Further investigations are needed to validate this hypothesis.     

Antifungal activity of microbial secondary metabolites

Secondary metabolites are well known for their ability to impede other microorganisms. Reanalysis of a screen of natural products using the Caenorhabditis elegans-Candida albicans infection model identified twelve microbial secondary metabolites capable of conferring an increase in survival to infected nematodes. In this screen, the two compound treatments conferring the highest survival rates were members of the epipolythiodioxopiperazine (ETP) family of fungal secondary metabolites, acetylgliotoxin and a derivative of hyalodendrin. The abundance of fungal secondary metabolites indentified in this screen prompted further studies investigating the interaction between opportunistic pathogenic fungi and Aspergillus fumigatus, because of the ability of the fungus to produce a plethora of secondary metabolites, including the well studied ETP gliotoxin. We found that cell-free supernatant of A. fumigatus was able to inhibit the growth of Candida albicans through the production of a secreted product. Comparative studies between a wild-type and an A. fumigatus ΔgliP strain unable to synthesize gliotoxin demonstrate that this secondary metabolite is the major factor responsible for the inhibition. Although toxic to organisms, gliotoxin conferred an increase in survival to C. albicans-infected C. elegans in a dose dependent manner. As A. fumigatus produces gliotoxin in vivo, we propose that in addition to being a virulence factor, gliotoxin may also provide an advantage to A. fumigatus when infecting a host that harbors other opportunistic fungi.     

Antifungal activity of three spermidine conjugates

Three tri-substituted spermidines, di-p-coumaroyl-caffeoylspermidine, tri-caffeoylspermidine and tri-p-coumaroylspermidine, isolated from pollen of Quercus alba, were examined for antifungal activity. Both di-p-coumaroyl-caffeoylspermidine and tri-p-coumaroylspermidine reduced mycelial growth of the oat leaf stripe pathogen, Pyrenophora avenae and reduced powdery mildew (Blumeria graminis f. sp. hordei) infection of barley seedlings when applied as a post-inoculation treatment. When used as a pre-inoculation treatment, only di-p-coumaroyl-caffeoylspermidine reduced powdery mildew infection significantly. Growth of P. avenae in the presence of 100 microM di-p-coumaroyl-caffeoylspermidine reduced activity of S-adenosylmethionine decarboxylase (AdoMetDC), and led to a reduction in the incorporation of labelled ornithine into spermidine. The other two spermidine conjugates increased AdoMetDC activity and the flux label from ornithine into spermine in P. avenae significantly.     

Antifungal activity of nontraditional antifungal agents

Invasive fungal infections are becoming increasingly important in the management of critically ill and immunocompromised patients. As organ and stem cell transplantation becomes more prominent and immune therapies are employed for diseases such as rheumatoid arthritis and plaque psoriasis, the population of patients at risk continues to grow. Many invasive fungal infections are associated with extremely high mortality rates. Antifungal options are limited and novel therapies are intriguing as we attempt to improve patient outcomes and preserve the antifungal armamentarium. Many other classes of pharmaceuticals typically seen as non-antifungal do in fact have significant antifungal activity. Prominent among these are calcineurin inhibitors, antiarrhythmics, antidepressants, antibacterials, and others. Some have activity alone and some augment the activity of conventional antifungals. Unfortunately, clinical data are lacking for most of these agents and their role in therapy remains undefined. This review focuses on several representative non-antifungal agents with antifungal activity.     

Antifungal activity of some mediterranean algae

Summary The antifungal activity of 15 mediterranean algae species on some dermatophyte strains (Epidermophyton floccosum, Microsporum canis, M. gypseum and Trichophyton mentagrophytes) and pathogenic yeasts (Candida albicans, C. guillermondii, C. krusei, C. tropicalis and Torulopsis glabrata) has been tested following a modification of Aubert's technique.Among the algae species studied, Falkenbergia rufolanosa is the most active in front of all the fungi tested.     

Antifungal activity of helenin and isohelenin

Two sesquiterpene lactones, helenin and isohelenin, were examined for their activity against 16 species of fungi. These compounds varied greatly in their antifungal activities. At concentrations of 10 μg/ml, the lactones strongly inhibited the growth of Microsporum cookei, Trichophyton mentagrophytes and Trichothecium roseum, while other fungi were only inhibited by considerably higher levels (100–1000 μg/ml). It is suggested that these secondary plant metabolites might be of potential use as antifungal agents, especially if their activity and specificity could further be enhanced through modifications in their chemical structure.     

Albumin is a redox-active crowding agent that promotes oxidative folding of cysteine-rich peptides

Oxidative folding that occurs in a crowded cellular milieu is characterized by multifaceted interactions that occur among nascent polypeptides and resident components of the endoplasmic reticulum (ER) lumen. Macromolecular crowding has been considered an essential factor in the folding of polypeptides, but the excluded volume effect has not been evaluated for small, disulfide-rich peptides. In the research presented, we examined how macromolecular crowding agents, such as albumin, ovalbumin, and polysaccharides, influenced the kinetics and thermodynamics of forming disulfide bonds in four model peptides of varying molecular size from 13 residues (1.4 kDa) to 58-residues (6.5 kDa): conotoxins: GI, PVIIA, r11a, and bovine pancreatic trypsin inhibitor. Our results indicate that the excluded volume effect does not significantly alter the folding rates nor equilibria for these peptides. In stark contrast, folding reactions were dramatically accelerated, when protein-based crowding agents were present at concentrations lower than those predicted to provide the excluded volume effect. Submillimolar albumin alone was as effective as glutathione in promoting the oxidative folding of GI conotoxin at concentrations typically found in the ER. To the best of our knowledge, this is the first report and quantitative characterization of oxidative folding of peptides mediated by other than thioredoxin-based protein disulfide bonds. Our work raises a possibility that concurrent secretory and ER-resident proteins may influence the oxidative folding of small, cysteine-rich peptides not as crowding agents, but as redox-active factors.