Occurrence of Deoxynivalenol and Ochratoxin A in Beers and Wines Commercialized in Paraguay.

Alcoholic beverages can be contaminated with mycotoxins. Ochratoxin A (OTA) is the most frequently detected mycotoxinin wine and is produced by several species of Aspergillus. This mycotoxin is nephrotoxic and carcinogenic. In beer, the most commonly identified mycotoxin is deoxynivalenol (DON). Ingestion of food contaminated with DON has been associated with adverse gastrointestinal effects. Despite the harmful effects of mycotoxins on health, there are no regulations regarding their limits in alcoholic beverages in Paraguay. Here we determine the presence of OTA and DON in wine and beer, respectively. Four commercial brands of wine and twenty-nine brands of craft and industrial beerwere tested by the Agra quant ELISA method. One brand of wine was positive for OTA and seven brands of beer (one of them craft) were positive for DON. The values found for both toxins are below the recommended maximum intake proposed by international standards. Giving the high consumption of these products in the country, regulations and monitoring systems mustbe established to check the maximum levels of mycotoxins allowed in alcoholic beverages.

Antifungal activity of geraniol and citronellol, two monoterpenes alcohols, against Trichophyton rubrum involves inhibition of ergosterol biosynthesis.

CONTEXT: Trichophyton rubrum is the most common fungus causing chronic dermatophytosis in humans. Antifungal activity of promising agents is of great interest. Geraniol and citronellol are monoterpenes with antimicrobial properties. OBJECTIVE: This study aimed to investigate the inhibitory effects and possible mechanism of antifungal activity of geraniol and citronellol against strains of T. rubrum. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of each drug against 14 strains was determined by broth microdilution. The effects of the drugs on dry mycelial weight, conidial germination, infectivity on human nail fragments, and morphogenesis of T. rubrum were analyzed. The effects on the cell wall (test with sorbitol) and cell membrane (release of intracellular material and ergosterol biosynthesis) were investigated. RESULTS: MIC values of geraniol ranged between 16 and 256 µg/mL while citronellol showed MIC values from 8 to 1024 µg/mL. The drugs (MIC and 2 × MIC) inhibited the mycelial growth, conidia germination, and fungal growth on nail fragments. The drugs (half of MIC) induced the formation of wide, short, and crooked hyphae in T. rubrum morphology. With sorbitol, geraniol MIC was increased by 64-fold and citronellol by 32-fold. The drugs caused leakage of intracellular material and inhibited ergosterol biosynthesis. DISCUSSION: The results suggest that the drugs damage cell wall and cell membrane of T. rubrum through a mechanism that seems to involve the inhibition of the ergosterol biosynthesis. CONCLUSION: This study confirms that geraniol and citronellol can be regarded as potential drugs for controlling T. rubrum growth, with great potential against agents of dermatophytosis.

Investigation on mechanism of antifungal activity of eugenol against Trichophyton rubrum.

Trichophyton rubrum is a worldwide agent responsible for chronic cases of dermatophytosis which have high rates of resistance to antifungal drugs. Attention has been drawn to the antimicrobial activity of aromatic compounds because of their promising biological properties. Therefore, we investigated the antifungal activity of eugenol against 14 strains of T. rubrum which involved determining its minimum inhibitory concentration (MIC) and effects on mycelial growth (dry weight), conidial germination and morphogenesis. The effects of eugenol on the cell wall (sorbitol protect effect) and the cell membrane (release of intracellular material, complex with ergosterol, ergosterol synthesis) were investigated. Eugenol inhibited the growth of 50% of T. rubrum strains employed in this study at an MIC = 256 µg/ml, as well as mycelial growth and conidia germination. It also caused abnormalities in the morphology of the dermatophyte in that we found wide, short, twisted hyphae and decreased conidiogenesis. The results of these studies on the mechanisms of action suggested that eugenol exerts antifungal effects on the cell wall and cell membrane of T. rubrum. Eugenol act on cell membrane by a mechanism that seems to involve the inhibition of ergosterol biosynthesis. The lower ergosterol content interferes with the integrity and functionality of the cell membrane. Finally, our studies support the potential use of the eugenol as an antifungal agent against T. rubrum.

Actividad antifúngica del aceite esencial de Eugenia caryophyllata sobre cepas de Candida tropicalis de aislados clínicos / Antifungal activity of the essential oil of Eugenia caryophyllata on Candida tropicalis strains from clinical isolates

Candidiasis is an opportunistic fungal infection caused by Candida yeasts. In Brazil, C. tropicalis is the second most frequently isolated microorganism after C. albicans. The arising of strains resistant to conventional antifungal agents has increased the search for new alternatives from natural products, especially essential oils. This research investigated essential oil activity against strains of C. tropicalis by disk diffusion method. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were also determinate. In the disk diffusion, the essential oils of Cinnamomum zeylanicum, Eugenia caryophyllata and Origanum vulgare had the highest inhibition zones values. MIC and MFC values of E. caryophyllata essential oil were 512 and 1024 ug/mL, respectively. MIC and MFC amphotericin B values were identical (2 ug/mL). Therefore, it was concluded that E. caryophyllata essential oil has strong antifungal activity and may be subject to further studies.

La candidiasis es una infección fúngica oportunista causada por levaduras del género Candida. En Brasil, la especie C. tropicalis esta siendo aislada frecuentemente, es el segundo microorganismo más aislado después de C. albicans. La aparición de cepas resistentes a los antifúngicos convencionales ha aumentado la búsqueda de nuevas alternativas provenientes de productos naturales, especialmente los aceites esenciales. En este estudio se investigó la actividad de los aceites esenciales contra las cepas de C. tropicalis, utilizando el método de difusión en disco, la concentración inhibitoria mínima (CIM) y la concentración fungicida mínima (CFM). En el método de difusión en disco, con los aceites esenciales de Cinnamomum zeylanicum, Eugenia caryophyllata y Origanum vulgare se obtuvieron mayores valores de inhibición. La CIM y CFM del aceite esencial de Eugenia caryophyllata fueron 512 y 1024 ug/mL, mientras que los de la anfotericina B fueron idénticos, 2 ug/mL. Por lo tanto, se puede concluir que el aceite esencial de E. caryophyllata tiene potente actividad antifúngica y puede ser objeto de nuevos estudios sobre esta actividad.

Increasing antibiotic activity against a multidrug-resistant Acinetobacter spp by essential oils of Citrus limon and Cinnamomum zeylanicum.

The genus Acinetobacter has gained importance in recent years due to involvement in serious infections and antimicrobial resistance. Many plants have been evaluated not only for direct antimicrobial activity, but also as resistance modifying agents. The Essential oil of Citrus limon (EOCL) addition at 156.25 µgmL(-1) (MIC/8) sub-inhibitory concentration in the growth medium led to MIC decrease for amikacin, imipenem and meropenem. The Essential oil of Cinnamomum zeylanicum (EOCZ) addition at 78.125 µg mL(-1) (MIC/8) sub-inhibitory concentrations in the growth medium caused drastic MIC reduction of amikacin. Results of combining antibiotics and essential oils had shown us a synergistic effect with both essential oils/amikacin combinations. An additive effect was observed with the combinations of both essential oils and gentamicin. The results of this study suggest that essential oil of C. limon and C. zeylanicum may suppress the growth of Acinetobacter species and could be a source of metabolites with antibacterial modifying activity.