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In this study the physicochemical characterization of the pulp and almond fixed oil was carried out; their antibacterial activity and aminoglycoside antibiotic modifying action against standard and multiresistant Gram-positive and -negative bacteria were investigated using the broth microdilution assay. Physical properties such as moisture, pH, acidity, peroxide index, relative density and refractive index indicate stability and chemical quality of the oils. In the GC/MS chemical composition analysis, a high unsaturated fatty acid content and the presence of oleic and palmitic acids were observed in the oils. In the antibacterial assay, more significant results were obtained for Escherichia coli, while other standard and multi-resistant strains presented MIC values ≥ 1024 μg/mL. Furthermore, the fixed oils in association with antibiotics were able to significantly improve antibacterial activity against S. aureus with a reduction in MICs. [ABSTRACT FROM AUTHOR]

Essential oils are new natural medicines, which have been studied extensively in recent years. In this paper, the chemical composition of the essential oil from Alpinia zerumbet leaves and its ability to modulate the activity of aminoglycoside antibiotics is reported. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography (GC) and GC–mass spectrometry (GC/MS). The antibacterial activity of the essential oil alone or in association with aminoglycosides was determined by a microdilution test against twelve strains (standards and multi-resistant clinical isolates obtained from sputum and wounds), seven Gram negative and five Gram positive. The major components identified by GC/MS were 4-terpineol (32.9 ± 4.0%), 1,8-cineole (21.4 ± 1.2%), γ-terpinolene (10.0 ± 1.8%) and sabinene (7.1 ± 4.6%), with a strong predominance of monoterpenes. The results indicated that the multi-resistant clinical isolates Staphylococcus aureus 358 and Escherichia coli 27 were more sensitive to the essential oil, exhibiting minimum inhibitory concentrations (MICs) of 32 and 128 μg/mL, respectively. The essential oil was capable of enhancing the antimicrobial activity of aminoglycosides against all strains tested, except for S. aureus 358. Very significant reductions in the MICs of the antibiotics were found, with a 94% decrease in MIC of neomycin against Klebsiella pneumoniae ATCC 10031. The results obtained indicate that the A. zerumbet essential oil has a significant synergistic antibiotic effect when combined with aminoglycosides, demonstrating that its constituents may act as potentiators of the antibiotic activity of aminoglycosides. [ABSTRACT FROM AUTHOR]

The leaves of Lantana camara L. (Verbenaceae) were subjected to hydrodistillation, and the essential oil extracted was examined with respect to chemical composition, antibacterial and antibiotic modifying activity by gaseous contact. Among the 25 identified components, bicyclogermacrene (26.1%), β-caryophyllene (24.4%), germacrene D (19.2%) and valecene (12.0%) were the main constituents. The essential oil volatile constituents inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa with MIC of 1 and > 1 mg/L, respectively. The activity of the antibiotic amikacin was increased by 65% against S. aureus and P. aeruginosa after contact with the volatile components. [ABSTRACT FROM AUTHOR]

The leaves of Lantana montevidensis Briq. (Verbenaceae) were subjected to hydrodistillation, and the essential oil extracted was examined with respect to chemical composition, antibacterial and antibiotic modifying activity by gaseous contact. Among the 19 identified components, β-caryophyllene (31.50%), germacrene D (27.50%) and bicyclogermacrene (13.93%) were the main constituents. The essential oil volatile constituents inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa with a MID o 0.25 and > 1 mg/L, respectively. The activity of the antibiotics gentamicin and amikacin was reinforced against S. aureus and P. aeruginosa (with a 102% of amikacin activity against P. aeruginosa) after contact with the volatile components, showing that this oil influences the activity of the antibiotic and may be used as an adjuvant in the antibiotic therapy of respiratory tract bacterial pathogens. [ABSTRACT FROM AUTHOR]

In this work, the chemical constituents, antibacterial and modulatory activities of the essential oil of Lantana camara Linn were studied. The essential oil was extracted from the leaves of L. camara by hydrodistillation method using Clevenger's apparatus and its chemical constituents were separated and identified by GC-MS, and the relative content of each constituent was determined by area normalization. Among the 25 identified components, bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valecene (12.94%) and germacrene D (12.34%) were the main constituents. The oil was examined to antibacterial and modulatory activities against the multiresistant strains of Escherichia coli and Staphylococcus aureus by microdilution test. The results show an inhibitory activity to E. coli (MIC 512 μg/ml) and S. aureus (MIC 256 μg/ml). The synergism of the essential oil and aminoglycosides was verified too, with significant reduction of MICs (7x, 1250-5 μg/ml) against E. coli. It is suggested that the essential oil of Lantana camara Linn could be used as a source of plant-derived natural products with resistance-modifying activity. [ABSTRACT FROM AUTHOR]

To verify the composition variation of its essential oil along 24 hours, leaves of Lantana camara Linn. of medicinal plant collection of the Department of Chemical Biology of URCA-Crato-CE, were collected every three hours during one day (of the 07:00 to 19:00 h) in April, 2008. The leaves had its oil extracted by hydro-distillation in Clevenger apparatus during three hours with two repetitions. The chemical composition analysis of the extracted essential oils was carried out in gas chromatography/mass spectroscopy. The phytochemical profile of the essential oils presented significant difference in function of the harvest. The seven most abundant were: germacrene D (24.50-6.15%), biciclogermacrene (33.32-14.27%), spathulenol (25.04-1.06%), eremophilene (20.64-1.93%), valecene (33.70-0.84%), viridiflorene (19.46%) and 1,10-di-epi-cubenol (27.93-21.32). The different result found here indicates the existence of different chemotypes of L. camara. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the antifungal and modulatory potential of the Ziziphus joazeiro bark and leaf extracts, both in isolation and in association with fluconazole, against resistant species from the Candida genus. Antifungal assays were used to determine the half maximal inhibitory concentration (IC50) of the extract in isolation and in combination with fluconazole using the broth microdilution method and spectrophotometric readings, followed by verification of the minimum fungicidal concentration by solid medium subculture. According to the cell viability curve, both extracts inhibited fungal growth in a concentration dependent manner, in addition to showing inhibitory concentrations similar to fluconazole. However, the extracts behaved in a fungistatic manner with minimum inhibitory concentration > 8.19 mg/mL and IC50 values ranging from 0.450 mg/mL to 9 mg/mL. The minimum inhibitory concentration for both extracts decreased when in combination with fluconazole, with the AEL standing out against Candida albicans URM 4387, displaying an IC50 equal to that of fluconazole (0.002 mg/mL). Nevertheless, fluconazole antagonism was observed against the tested strains. Overall, the evaluation of both extracts against Candida spp. presented inhibitory concentration values greater than fluconazole. Moreover, despite these being chemically complex crude extracts, they did demonstrate antifungal effects and properties that concur with their ethno-biological aspect.