Actividad antimicrobiana del aceite esencial de hojas de Psidium cattleianum Afzel. ex Sabine / Antimicrobial activity of essential oil from Psidium cattleianum Afzel. ex Sabine leaves

La búsqueda de fuentes naturales para controlar los microorganismos es de interés en la producción de alimentos. Este estudio evaluó la composición química y la actividad antimicrobiana del aceite esencial de las hojas de Psidium cattleianum. El aceite esencial se extrajo por hidrodestilación y se identificó por GC-MS. La clase predominante de compuestos fueron los sesquiterpenos (47,6%) y los principales fueron trans-ß-cariofileno (14,7%), 1,8-cineol (11,7%) y É£-muuroleno (5,6%). Actividad antimicrobiana se realizó mediante la técnica de microdilución contra ocho hongos y ocho bacterias. Concentración inhibitoria mínima varió de 0,17 a 11,25 mg mL-1 para hongos y de 1,40 a 16,87 mg mL-1 para bacterias. Principales actividades fueron contra hongos Aspergillus fumigatus (ATCC 1022), Aspergillus ochraceus (ATCC 12066), Aspergillus versicolor (ATCC 11730) y Trichoderma viride (IAM 5061), y bacterias Pseudomonas aeruginosa (ATCC 27853), Bacillus cereus (clinical isolate) y Staphylococcus aureus (ATCC 6538) con potencial para prevenir enfermedades transmitidas por alimentos.

The search for natural sources to control microorganisms is of interest in food production. This study evaluated the chemical composition and antimicrobial activity of the essential oil from Psidium cattleianum leaves. The essential oil was extracted by hydrodistillation, and identified by GC-MS. The predominant class of compounds was sesquiterpenes (47.6%) and the major compounds were trans-ß-caryophyllene (14.7%), 1,8-cineole (11.7%) and É£-muurolene (5.6%). The antimicrobial activity was carried out by microdillution technique against eight fungi and eight bacteria. The minimum inhibitory concentration ranged from 0.17 to 11.25 mg mL-1 for fungi, and from 1.40 to 16.87 mg mL-1 for bacteria. The highest activities were against fungi Aspergillus fumigatus (ATCC 1022), Aspergillus ochraceus (ATCC 12066), Aspergillus versicolor (ATCC 11730), and Trichoderma viride (IAM 5061), and bacteria Pseudomonas aeruginosa (ATCC 27853), Bacillus cereus (clinical isolate), and Staphylococcus aureus (ATCC 6538) with potential to prevent foodborne diseases.

The effect of Agaricus brasiliensis extract supplementation on honey bee colonies

ABSTRACT This study was done to discover any beneficial effect of a medicinal mushroom Agaricus brasiliensis extract on the honey bee. Firstly, a laboratory experiment was conducted on 640 bees reared in 32 single-use plastic rearing cups. A. brasiliensis extract proved safe in all doses tested (50, 100 and 150 mg/kg/day) irrespective of feeding mode (sugar syrup or candy). Secondly, a three-year field experiment was conducted on 26 colonies treated with a single dose of A. brasiliensis extract (100 mg/kg/day) added to syrup. Each year the colonies were treated once in autumn and twice in spring. The treatments significantly increased colony strength parameters: brood rearing improvement and adult population growth were noticed more often than the increase in honey production and pollen reserves. These positive effects were mainly observed in April. In conclusion, A. brasiliensis extract is safe for the bees and helps maintaining strong colonies, especially in spring.

Chemical composition, antifungal and antioxidant activity of Pelargonium graveolens essential oil.

The present study describes the chemical composition, antifungal and antioxidant activity of Pelargonium graveolens essential oil. The essential oil profile was determined by GC and GC-MS. The main compounds were citronellol (24.54%), geraniol (15.33%), citronellyl formate (10.66%) and linalool (9.80%). Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) were recorded using the microdilution and macrodilution methods. Commercial antimycotic bifonazol was used as a control. The concentration of 0.25-2.5 mg/ml showed fungicidal activity. The most resistant fungi were Mucor mucedo and Aspergillus species. The antioxidant activity of pure essential oil was evaluated by means of the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical assay. The essential oil of P. graveolens was able to reduce DPPH radicals into the natural DPPH-H form, and this activity was dose-dependent. The oil exhibited antioxidant activity and reduced DPPH to 50% at EC50 value of 0.802 mg/ml of oil solution.

Chemical characterization of Lippia alba essential oil: an alternative to control green molds

The essential oil of Lippia alba is reported as an antifungal against human pathogenic microorganisms but few articles report its use as an alternative to synthetic fungicides on green mould control. The objective of this study was to determine chemical characteristics of L. alba essential oil and its antifungal activity against green molds as an alternative to synthetic fungicides. Essential oil was extracted by Clevenger hydrodistillation, characterized by GC-MS analysis, and the structure of the main compounds confirmed by ¹H and 13C-NMR spectroscopy. Microdilution assays evaluated the essential oil minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Commercial fungicides Ketoconazole and Bifonazole were used as control. Essential oil yield is of 0.15 percent and the major components are neral (33.32 percent) and geranial (50.94 percent). The L. alba essential oil has MIC of 0.300-1.250 mg/mL and MFC of 0.600-1.250 mg/mL. Ketoconazole and Bifonazole show MIC ranging from 0.025-0.500 to 0.100-0.200 mg/mL, and MFC ranging from 0.250-0.100 to 0.200-0.250 mg/mL, respectively. L. alba essential oil is classified as citral type and the results indicate that it is a potential alternative to synthetic fungicides.