Detection of 2-ethyl-1-hexanol and its modulating effect in biofilm of Fusarium oxysporum.

In immunocompetent individuals, Fusarium spp. stands out as the causative agent of onychomycosis, among the non-dermatophyte molds. Despite evidence indicating that Fusarium oxysporum organizes itself in the form of a biofilm causing onychomycosis, there is little literature on the etiopathogenesis of the biofilm on the nail, specifically the signaling molecules present, known as quorum sensing (QS). Thus, this study detected the presence of a molecule related to QS from the ex vivo biofilm of F. oxysporum on human nail and investigated its effect on preformed biofilm in vitro. The detection and physicochemical characterization of a QS molecule, from the extracellular matrix (ECM), was carried out by Fourier transform infrared (FTIR) spectroscopy with an attenuated total reflectance (ATR) accessory and by headspace gas chromatography coupled to mass spectrometry (GC-MS) analyses. Determination of viable cells, cell activity, total biomass, ECM components and scanning electron microscopy (SEM) were performed to evaluate the influence of the QS molecule on the in vitro biofilm of F. oxysporum. The beginning, in the ex vivo biofilm of F. oxysporum on human nails, the volatile organic compound 2-ethyl-1-hexanol (2EH) was detected as a component of QS. Thereafter in vitro analyses, synthetic 2EH was able to modulate the biofilm by stimulating its filament, increasing total biomass and ECM production in terms of total carbohydrates, but with a reduction in total proteins and nucleic acids. We thus evidence, for the first time, the presence of 2EH in the biofilm of F. oxysporum, developed on the human nail, and the in vitro action of this compound as a QS molecule.

Bioactive natural products from orchids native to the Americas - A review.

The purpose of this review is to provide information on the traditional uses, phytochemical and pharmacological studies performed with species of orchids native to the Americas and the Caribbean Islands. The treatment of inflammation is the most traditional use for plants of this family, specially in Central America, while anti-inflammatory and anticancer assays are oftenly reported in pharmacological investigations. From the chemical point of view, they are sources of phenanthrenoids and stilbenes, rare secondary metabolites not commonly found in other families of plants, as well as cycloartane triterpenes, pyrrolizidine alkaloids and flavonoids. Since just few species were chemically and pharmacologically studied, in comparison to the large number of native species (less than 0.5% of the total), the orchids of the New World may be an interesting niche for the discovery of new, bioactive natural products.

Antiproliferative activity and energy calculations of a new triterpene isolated from the palm tree Acrocomia totai.

Acrocomia totai Mart (Arecaceae) is a palm tree native to South America, widely studied for biodiesel production. The aim of this work was to perform the first phytochemical study of A. totai leaves, as well as to do biological assays against human cancer cell lines. A new triterpene of the hopane class named totaiol (1), three known triterpenes (2-4), and two phytosteroids (5-6) were identified. The new natural product was characterized using 1 D and 2 D NMR, single crystal X-ray diffraction analises, and high resolution mass spectrometry. The intercontacts in the crystal packing were also analised. Complete stereochemical characterization of compound 1 revealed an unusual positioning pattern for methyl and isopropenyl groups in the polycyclic skeleton. Compounds 1-5 were evaluated for the first time in antiproliferative assays against Ca Ski, MCF-7 and MCF-10 cells. The new natural product was active against Ca Ski cells with IC50 ≤ 6.25 µg mL-1.

Kopsanone and N-oxide isolated from Aspidosperma macrocarpon Mart. (Apocynaceae) leaves and their MAO-A inhibitory activity.

Aspidosperma macrocarpon Mart., popularly known as 'guatambu' or 'peroba', is found from North American (Mexico) to South American (Argentina) continents and in Brazil. Two indole alkaloids were isolated from leaves of A. macrocarpon, kopsanone (1) and unreported N(4)-oxide-kopsanone (2).

The ability of farnesol to prevent adhesion and disrupt Fusarium keratoplasticum biofilm.

A biofilm is represented by a community of microorganisms capable of adhering to a surface and producing substances that envelop the cells, forming an extracellular matrix. The extracellular matrix is responsible for protecting microorganisms against environmental stress, hosts the immune system and confers resistance to antimicrobials. Fusarium keratoplasticum is a common species of FSSC (Fusarium solani species complex) associated with human infections, being the most prevalent species related to biofilm formation in hospital water systems and internal pipelines. With this in mind, this study aimed to characterise the biofilm formed by the fungus F. keratoplasticum and to evaluate the effects of farnesol, a fungal quorum sensing (QS) molecule, on the preformed biofilm and also during its formation at different times (adhesion and 24, 48 and 72 h). F. keratoplasticum is able to adhere to an abiotic surface and form a dense biofilm in 72 h, with increased total biomass and matrix modulation with the presence of extracellular DNA, RNA, polysaccharides and proteins. Farnesol exhibited important anti-biofilm activity, causing the destruction of hyphae and the extracellular matrix in preformed biofilm and preventing the adhesion of conidia, filamentation and the formation of biofilm. Few studies have characterised the formation of biofilm by filamentous fungi. Our findings suggest that farnesol acts efficiently on F. keratoplasticum biofilm since this molecule is capable of breaking the extracellular matrix, thereby disarranging the biofilm.

A new method for asperphenamate synthesis and its antimicrobial activity evaluation.

Asperphenamate is a natural phenylalanine derivative. This compound was produced through a new, two-step synthetic route. It was also evaluated by the antimicrobial activity of the pure substance against Escherichia coli, Staphylococcus aureus and Cladosporium herbarum.