Protease-inhibiting, molecular modeling and antimicrobial activities of extracts and constituents from Helichrysum foetidum and Helichrysum mechowianum (compositae)

Background Helichrysum species are used extensively for stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. It has been reported that Helichysum species are used to relief abdominal pain, heart burn, cough, cold, wounds, female sterility, menstrual pain. Results From the extracts of Helichrysum foetidum (L.) Moench, six known compounds were isolated and identified. They were 7, 4′-dihydroxy-5-methoxy-flavanone (1), 6′-methoxy-2′,4, 4′-trihydroxychalcone (2), 6′-methoxy-2′,4-dihydroxychalcone -4′-O-β-D-glucoside (3), apigenin (4), apigenin-7-O-β-D-glucoside (5), kaur-16-en-18-oic acid (6) while two known compounds 3,5,7-trihydroxy-8-methoxyflavone (12), 4,5-dicaffeoyl quinic acid (13) together with a mixture of phytosterol were isolated from the methanol extract of Helichrysum mechowianum Klatt. All the compounds were characterized by spectroscopic and mass spectrometric methods, and by comparison with literature data. Both extracts and all the isolates were screened for the protease inhibition, antibacterial and antifungal activities. In addition, the phytochemical profiles of both species were investigated by ESI-MS experiments. Conclusions These results showed that the protease inhibition assay of H. foetidum could be mainly attributed to the constituents of flavonoids glycosides (3, 5) while the compound (13) from H. mechowianum contributes to the stomach protecting effects. In addition, among the antibacterial and antifungal activities of all the isolates, compound (6) was found to possess a potent inhibitor effect against the tested microorganisms. The heterogeneity of the genus is also reflected in its phytochemical diversity. The differential bioactivities and determined constituents support the traditional use of the species. Molecular modelling was carried out by computing selected descriptors related to drug absorption, distribution, metabolism, excretion and toxicity (ADMET).

Evaluation of mutagenicity and metabolism-mediated cytotoxicity of the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin from Paepalanthus latipes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Saccharomyces cerevisiae: a novel and efficient biological control agent for Colletotrichum acutatum during pre-harvest

In this study, we evaluated the efficiency of six isolates of Saccharomyces cerevisiae in controlling Colletotrichum acutatum, the causal agent of postbloom fruit drop that occur in pre-harvest citrus. We analyzed the mechanisms of action involved in biological control such as: production of antifungal compounds, nutrient competition, detection of killer activity, and production of hydrolytic enzymes of the isolates of S. cerevisiae on C. acutatum and their efficiency in controlling postbloom fruit drop on detached citrus flowers. Our results showed that all six S. cerevisiae isolates produced antifungal compounds, competed for nutrients, inhibited pathogen germination, and produced killer activity and hydrolytic enzymes when in contact with the fungus wall. The isolates were able to control the disease when detached flowers were artificially inoculated, both preventively and curatively. In this work we identified a novel potential biological control agent for C acutatum during pre-harvest. This is the first report of yeast efficiency for the biocontrol of postbloom fruit drop, which represents an important contribution to the field of biocontrol of diseases affecting citrus populations worldwide. (C) 2015 Elsevier GmbH. All rights reserved.

Antifungals and acetylcholinesterase inhibitors from the stem bark of Croton heliotropiifolius

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and characterization of an antibacterial and non-toxic dimeric peptide derived from the C-terminal region of Bothropstoxin-I

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A flow cytometry method for testing the susceptibility of Cryptococcus spp. to amphotericin B

Human fungal infections have increased at an alarming rate in recent years, particularly in immunocompromised individuals. Cryptococcosis is the second most prevalent systemic fungal infection worldwide, and the most prevalent systemic infection in immunocompromised individuals, representing more than 70% of cases. The incidence of cryptococcosis is high in people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. The aim of this research was to develop a rapid flow cytometric antifungal susceptibility test and to compare the results with the standard methods. A reference strain and clinical isolates of Cryptococcus neoformans and Cryptococcus gattii were tested for susceptibility to amphotericin B by flow cytometry using propidium iodide as indicator of viability. Flow cytometry (FC) results were compared with the minimum inhibitory concentration (MIC) values determined by microdilution. The antifungal activity of amphotericin B ranged from MICs of 0.06 to 2μg/ml for the 11 isolates studied. The same results were found by FC. The FC method allows same-day results, assisting in the selection of appropriate antifungal therapies. These results demonstrate an excellent correlation between FC and the classic methods of testing for susceptibility to antifungal agents. This rapid diagnosis method makes it possible to quickly administer effective therapeutic interventions, often saving lives.

Nanostructured lipid system as a strategy to improve the anti-Candida albicans activity of Astronium sp

The genus Astronium (Anacardiaceae) includes species, such as Astronium fraxinifolium, Astronium graveolens, and Astronium urundeuva, which possess anti-inflammatory, anti-ulcerogenic, healing, and antimicrobial properties. Nanostructured lipid systems are able to potentiate the action of plant extracts, reducing the required dose and side effects and improving antimicrobial activity. This work aims to evaluate a nanostructured lipid system that was developed as a strategy to improve the anti-Candida albicans activity of hydroethanolic extracts of stems and leaves from Astronium sp. The antifungal activity against C. albicans (ATCC 18804) was evaluated in vitro by a microdilution technique. In addition to the in vitro assays, the Astronium sp. that showed the best antifungal activity and selectivity index was submitted to an in vivo assay using a model of vulvovaginal candidiasis infection. In these assays, the extracts were either used alone or were incorporated into the nanostructured lipid system (comprising 10% oil phase, 10% surfactant, and 80% aqueous phase). The results indicated a minimal inhibitory concentration of 125.00 µg/mL before incorporation into the nanostructured system; this activity was even more enhanced when this extract presented a minimal inhibitory concentration of 15.62 µg/mL after its incorporation. In vivo assay dates showed that the nanostructure-incorporated extract of A. urundeuva leaves was more effective than both the unincorporated extract and the antifungal positive control (amphotericin B). These results suggest that this nanostructured lipid system can be used in a strategy to improve the in vitro and in vivo anti-C. albicans activity of hydroethanolic extracts of Astronium sp.

Evaluating the microbicidal, antiparasitic and antitumor effects of CR-LAAO from Calloselasma rhodostoma venom

CR-LAAO is an l-amino acid oxidase from Calloselasma rhodostoma snake venom that has been broadly studied regarding its structural and biochemical characteristics, however, few studies have investigated its pharmacological effects. The present study aimed at the evaluation of the biotechnological potential of CR-LAAO by determining its bactericidal, antifungal, leishmanicidal and trypanocidal activity, as well as its cytotoxicity on human tumor and non-tumor cell lines. After 24h of preincubation, CR-LAAO showed bactericidal effects against both Staphylococcus aureus (MIC 0.78μg/mL) and Escherichia coli (MIC 31.25μg/mL) strains, inducing dismantle of bacterial cell walls. After 6h of preincubation with Candida albicans, CR-LAAO was able to inhibit 80% of the yeast growth, and it also showed cytotoxic activity on Leishmania species and Trypanosoma cruzi. Additionally, CR-LAAO showed high cytotoxicity on HepG2 and HL-60 tumor cells (IC50 10.78 and 1.7μg/mL), with lower effects on human mononuclear cells (PBMC). The cytotoxic effects of CR-LAAO were significantly inhibited in the presence of catalase, which suggests the involvement of hydrogen peroxide in its mechanisms of toxicity. Therefore, CR-LAAO showed promising pharmacological effects, and these results provide important information for the development of therapeutic strategies with directed action, such as more effective antimicrobial agents.

A curcumin-loaded liquid crystal precursor mucoadhesive system for the treatment of vaginal candidiasis

Women often develop vaginal infections that are caused primarily by organisms of the genus Candida. The current treatments of vaginal candidiasis usually involve azole-based antifungals, though fungal resistance to these compounds has become prevalent. Therefore, much attention has been given to molecules with antifungal properties from natural sources, such as curcumin (CUR). However, CUR has poor solubility in aqueous solvents and poor oral bioavailability. This study attempted to overcome this problem by developing, characterizing, and evaluating the in vitro antifungal action of a CUR-loaded liquid crystal precursor mucoadhesive system (LCPM) for vaginal administration. A low-viscosity LCPM (F) consisting of 40% wt/wt polyoxpropylene-(5)-polyoxyethylene-(20)-cetyl alcohol, 50% wt/wt oleic acid, and 10% wt/wt chitosan dispersion at 0.5% with the addition of 16% poloxamer 407 was developed to take advantage of the lyotropic phase behavior of this formulation. Notably, F could transform into liquid crystal systems when diluted with artificial vaginal mucus at ratios of 1:3 and 1:1 (wt/wt), resulting in the formation of F30 and F100, respectively. Polarized light microscopy and rheological studies revealed that F behaved like an isotropic formulation, whereas F30 and F100 behaved like an anisotropic liquid crystalline system (LCS). Moreover, F30 and F100 presented higher mucoadhesion to porcine vaginal mucosa than F. The analysis of the in vitro activity against Candida albicans revealed that CUR-loaded F was more potent against standard and clinical strains compared with a CUR solution. Therefore, the vaginal administration of CUR-loaded LCPMs represents a promising platform for the treatment of vaginal candidiasis.

Phytochemical characterization, antimicrobial activity, and antioxidant potential of Equisetum hyemale L. (Equisetaceae) extracts

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Disseminated cutaneous histoplasmosis in elderly patients. An uncommon presentation

Background: Human fungal infections have increased at an alarming rate in recent years, particularly in immunocompromised individuals. Cryptococcosis is the second most prevalent systemic fungal infection worldwide, and the most prevalent systemic infection in immunocompromised individuals, representing more than 70% of cases. The incidence of cryptococcosis is high in people with HIV/acquired immunodefi- ciency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. Aims: The aim of this research was to develop a rapid flow cytometric antifungal susceptibility test and to compare the results with the standard methods. Methods: A reference strain and clinical isolates of Cryptococcus neoformans and Cryptococcus gattii were tested for susceptibility to amphotericin B by flow cytometry using propidium iodide as indicator of viability. Flow cytometry (FC) results were compared with the minimum inhibitory concentration (MIC) values determined by microdilution. Results: The antifungal activity of amphotericin B ranged from MICs of 0.06 to 2 g/ml for the 11 isolates studied. The same results were found by FC. Conclusions: The FC method allows same-day results, assisting in the selection of appropriate antifungal therapies. These results demonstrate an excellent correlation between FC and the classic methods of testing for susceptibility to antifungal agents. This rapid diagnosis method makes it possible to quickly administer effective therapeutic interventions, often saving lives.

Antimicrobial and antileishmanial activities of diterpenoids isolated from the roots of salvia deserta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Participation of dectin-1 receptor on NETs release against Paracoccidioides brasiliensis: role on extracellular killing

Paracoccidioides brasiliensis is a dimorphic fungus from the Paracoccidioides genus, which is the causative agent of paracoccidioidomycosis, a chronic, subacute or acute mycosis, with visceral and cutaneous involvement. This disease that is acquired through inhalation primarily attacks the lungs but, can spread to other organs. Phagocytic cells as neutrophils play an important role during innate immune response against this fungus, but studies on antifungal activities of these cells are scarce. In addition to their ability to eliminate pathogens by phagocytosis and antimicrobial secretions, neutrophils can trap and kill microorganisms by release of extracellular structures composed by DNA and antimicrobial proteins, called neutrophil extracellular traps (NETs). Here, we provide evidence that P. brasiliensis virulent strain (P. brasiliensis 18) induces NETs release. These structures were well evidenced by scanning electron microscopy, and specific NETs compounds such as histone, elastase and DNA were shown by confocal microscopy. In addition, we have shown that dectin-1 receptor is the main PRR to which fungus binds to induce NETS release. Fungi were ensnared by NETs, denoting the role of these structures in confining the fungus, avoiding dissemination. NETs were also shown to be involved in fungus killing, since fungicidal activity detected before and mainly after neutrophils activation with TNF-α, IFN-γ and GM-CSF was significantly inhibited by cocultures treatment with DNAse.

Crystal structure of mature 2S albumin from Moringa oleifera seeds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Participação das células Th1, Th2, Th17 e T regulatórias na doença de Jorge Lobo: análise do perfil de expressão gênica nas lesões

Pós-graduação em Doenças Tropicais - FMB