In vitro antifungal activity of heterocyclic organoboron compounds against Trichophyton mentagrophytes and Microsporum canis obtained from clinical isolates

The aim of this study was to investigate the in vitro activity of thirty-eight heterocyclic organoboron compounds (1a-o, 2a-j, 3a-m) against clinically isolated dermatophytes Trichophyton mentagrophytes and Microsporum canis. Minimum inhibitory concentrations (MICs) of compounds (1a-o, 2a-j, 3a-m) were determined according to published protocol Clinical and Laboratory Standards Institute (CLSI) M38-A2 broth microdilution method. The minimum fungicidal concentrations (MFCs) for both T. mentagrophytes and M. canis were found by subculturing each fungal suspension on potato dextrose agar. According to the results, heterocyclic organoboron compounds (1a-o, 2a-j, 3a-m) were found to be more effective against dermatophyte M. canis (MIC = 3.12-25 µg/ml) than T. mentagrophytes (MIC = 12.5-100 µg/ml). Our findings showed that 7-membered heterocyclic organoboron compounds (3a-m) (MIC = 12.5-50 µg/ml) have stronger in vitro antifungal activity against T. mentagrophytes than 5-membered heterocyclic organoboron compounds (1a-o, 2a-j) (MIC = 25-100 µg/ml). The MFC values for all compounds ranged from 6.25 to 200 µg/ml. The limited number of systemic antifungal agents used in the treatment of dermatophyte infections and the presence of side effects have led to the search for new treatment resources in recent years. Therefore, investigation of the effect of heterocyclic organoboron compounds against dermatophytes will be promising for the discovery of new antifungal compounds that have gained great importance today.

USO DOS ÓLEOS ESSENCIAIS EM ONICOMICOSE: REVISÃO INTEGRATIVA

Objetivo:identificar na literatura como os óleos essenciais são utilizados em onicomicose. Métodos: revisão integrativa com buscas realizadas nas bases de dados MEDLINE/PubMed, Web of Science, Cochrane, SCOPUS e BVS, sendo 13 estudos analisados. Resultados: o uso de óleos essenciais Melaleucaalternifólia, Lavandulaangustifólia, Eucalyptuscitriodora e Foeniculumvulgare mostram-se eficazes e trazem benefícios no tratamento da onicomicose, por inibirem o crescimento micelial dos fungos infectantes das unhas. Sendo assim, os profissionais de saúde envolvidos nos cuidados em pessoas com onicomicose devem se manter atualizados sobre tais alternativas de tratamento e consequentemente da melhora da assistência prestada a esses pacientes. Conclusão: a eficácia antifúngica de uma variedade de óleos foi comprovada com diferentes formas de apresentação e possíveis associações. Entretanto, o nível da evidência apresentado foi baixo, o que justifica a necessidade de estudos mais robustos sobre a temática.

USE OF ESSENTIAL OILS IN ONYCHOMYCOSIS: AN INTEGRATIVE REVIEW

Objective: identify in the literature how essential oils are used in onychomycosis. Methods: integrative review with searches performed in the MEDLINE/PubMed, Web of Science, Cochrane, SCOPUS and BVS databases, with 13 studies analyzed. Results: the use of essential oils Melaleuca alternifolia, Lavandula angustifolia, Eucalyptus citriodora and Foeniculum vulgare are effective and bring benefits in the treatment of onychomycosis, as they inhibit the mycelial growth of the nail fungus. Therefore, health professionals involved in the care of people with onychomycosis must keep themselves updated on such treatment alternatives and, consequently, on improving the care provided to these patients. Conclusion: the antifungal efficacy of a variety of oils has been proven with different forms of presentation and possible associations. However, the level of evidence presented was low, which justifies the need for more robust studies on the subject.

Combined Effect of Vacuum Packaging, Fennel and Savory Essential Oil Treatment on the Quality of Chicken Thighs

The aim of the present work was to evaluate the microbiological quality of chicken thighs after treatment by fennel (Foeniculum vulgare) and savory (Satureja hortensis) essential oil, stored under vacuum packaging (VP) at 4 ± 0.5 °C for a period of 16 days. The following treatments of chicken thighs were used: Air-packaging control samples (APCS), vacuum-packaging control samples (VPC), vacuum-packaging (VP) control samples with rapeseed oil (VPRO), VP (vacuum-packaging) with fennel essential oil at concentrations 0.2% v/w (VP + F), and VP with savory essential oil at concentration 0.2% v/w (VP + S). The quality assessment of APCS, VPC, VPRO, VP + F and VP + S products was established by microbiological analysis. The microbiological parameters as the total viable counts of bacteria of the Enterobacteriaceae family, lactic acid bacteria (LAB), and Pseudomonas spp. were detected. Bacterial species were identified with the MALDI-TOF MS Biotyper. The combination of essential oils and vacuum packaging had a significant effect (p < 0.05) on the reduction of total viable counts (TVC) compared with control group without vacuum packaging and the untreated control group. Though 15 genera and 46 species were isolated with scores higher than 2.3 from the chicken samples.

Development of new active packaging film made from a soluble soybean polysaccharide incorporating ZnO nanoparticles

This study aimed to develop a soluble soybean polysaccharide (SSPS) nanocomposite incorporating ZnO nanoparticles. The nanocomposites were prepared using the solvent-casting method. SEM, AFM, DSC and X-ray diffraction methods were applied to characterize the resulting films. Furthermore, the antibacterial and anti-mold activities of SSPS/ZN films were assessed against the selected microorganisms. The results indicated that incorporating ZNs into the SSPS film affected the tensile strength and elongation at break significantly. In addition, the antibacterial, antifungal and yeasticidal activities of ZnO/SSPS films have been approved. XRD results showed a crystal plane of hexagonal ZN, while SEM showed that there was not a good affinity between ZN and SSPS. Mono-dispersed particles with clearly spherical morphology and with no voids on the surface were observed using AFM. Fluctuation in Tg and Tm resulted from incorporating ZN. In summary, the potential of ZNs as a functional filler in SSPS film has been demonstrated.

Investigation of optimal extraction, antioxidant, and antimicrobial activities of Achillea biebersteinii and A. wilhelmsii

OBJECTIVE

Achillea species are endowed with multiple biological activities including antioxidant properties. However, no study has yet investigated the impact of extraction method and pH on the biological activities of these plants. The present study aimed to investigate the antioxidant and antimicrobial effects of methanol extracts from the aerial parts of the species Achillea biebersteinii Afan and Achillea wilhelmsii C. Koch (Asteraceae). In addition, the impact of extraction method and pH on these biological activities was evaluated.

MATERIALS AND METHODS

Methanol extracts of A. biebersteinii and A. wilhelmsii were prepared using classical maceration and high-intensity ultrasound methods. Ultrasound-assisted extraction was performed at three different pH values: 5.7, 6.3 and 6.9.

RESULTS

Total phenolic compounds (range: 20.16-108.54 vs. 17.18-59.61 mg gallic acid equivalent/g sample in A. biebersteinii and A. wilhelmsii, respectively), total flavonoids (range: 8.33-12.97 vs. 7.79-9.41 mg catechin equivalent/g sample), 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (IC₅₀: 40.63-346.34 vs. 84.02-462.41) and reducing power (IC₅₀: 504.44-4406.67 vs. 1710.00-5501.67) were significantly higher in A. biebersteinii vs. A. wilhelmsii and ultrasound-assisted vs. classical maceration extracts of both species. The aforementioned items were higher at pH = 6.3, followed by pHs of 6.9 and 5.7, respectively. Overall, A. biebersteinii extracts were more active against all of the tested microorganisms than A. wilhelmsii. Sensitivities of Gram-positive bacteria were higher for both Achillea extracts than the Gram-negative bacteria. No observable inhibitory activity was found from different extracts against Aspergillus niger.

CONCLUSION

The findings of the present study suggest that methanol extracts of A. biebersteinii and A. wilhelmsii possess antioxidant and antimicrobial activity, being higher in the former. Ultrasound-assisted extraction and pH of 6.3 have significant augmenting impact on the total phenolic and flavonoid content as well as antioxidant activities of both species.

Antimicrobial activities of essential oil and hexane extract of Florence fennel [Foeniculum vulgare var. azoricum (Mill.) Thell.] against foodborne microorganisms

The objective of this study was to determine the chemical compositions of the essential oil and hexane extract isolated from the inflorescence, leaf stems, and aerial parts of Florence fennel and the antimicrobial activities of the essential oil, hexane extract, and their major component, anethole, against a large variety of foodborne microorganisms. Gas chromatography and gas chromatography-mass spectrometry analysis showed that the essential oils obtained from inflorescence, leaf stems, and whole aerial parts contained (E)-anethole (59.28-71.69%), limonene (8.30-10.73%), apiole (trace to 9.23%), beta-fenchyl acetate (3.02-4.80%), and perillene (2.16-3.29%) as the main components. Likewise, the hexane extract of the plant sample exhibited a similar chemical composition, and it contained (E)-anethole (53.00%), limonene (27.16%), gamma-terpinene (4.09%), and perillene (3.78%). However, the hexane extract also contained less volatile components such as n-hexadecanoic acid (1.62%), methyl palmitate (1.17%), and linoleic acid (1.15%). The in vitro antimicrobial assays showed that the essential oil, anethole, and hexane extract were effective against most of the foodborne pathogenic, saprophytic, probiotic, and mycotoxigenic microorganisms tested. The results of the present study revealed that (E)-anethole, the main component of Florence fennel essential oil, is responsible for the antimicrobial activity and that the essential oils as well as the hexane extract can be used as a food preservative. This study is the first report showing the antimicrobial activities of essential oil and hexane extract of Florence fennel against probiotic bacteria.

Combinatorial anti-Trichophyton effects of Ligusticum chuanxiong essential oil components with antibiotics

The antifungal activities of ligustilide and butylidene phthalide, which are major oil components comprising the essential oil of Ligusticum chuanxiong, in combination with antifungal drugs were evaluated. Checkerboard microtiter and microdilution tests were used to measure combined effects against Trichophyton species, T. erinacei, T. mentagrophytes, T. rubrum, T. schoenleinii, T. tonsurans and T. soudanense. Susceptibility of these Trichophyton species to L. chuanxiong essential oil differed distinctly. The fractional inhibitory concentrations (FICIs) against Trichophyton species ranged between 0.27 and 0.56 for ketoconazole combined with ligustilde or butylidene phthalide, indicating synergism or additive effects between the antibiotic and essential oil compounds. Testing by itraconazole instead of ketoconazole, similar combination effects were observed with FICIs from 0.31 to 0.63 against the tested strains of T. mentagrophytes, T. rubrum, T. schoenleinii, and T. soudanense. Thus, data reported here showed that Trichophyton susceptibility to ketoconazole and itraconazole could be notably improved by ligustilde and butylidene phthalide.

Antifungal Effect of Eugenol and Nerolidol against Microsporum gypseum in a Guinea Pig Model

Essential oils have been widely used in anti-infectious application. In the present study, we elucidated the antifungal activities of eugenol and nerolidol isolated from Japanese cypress oil in a guinea pig model infected by Microsporum gypseum (M. gypseum). A minimal inhibitory concentration (MIC), skin lesion scoring, hair culture and histopathologic examination of skin tissues were performed to evaluate the antifungal effect of these oils. The MICs of eugenol, nerolidol and econazole (positive control) were 0.01-0.03% and 0.5-2% and 4-16 microg/ml, respectively. Based on these MICs, eugenol and nerolidol were adjusted to 10% concentration with a base of Vaseline petroleum jelly and were applied topically to the skin lesion infected with M. gypseum daily for 3 weeks. Both eugenol and nerolidol were clinically effective at improving the lesion during the first week of application, as determined by skin lesion scoring. Nerolidol improved the skin lesions infected by M. gypseum, but eugenol did not, as determined in the hair culture test. Histopathologic examination revealed that the eugenol- and nerolidol-treated groups had a lower degree of hyperkeratosis and inflammatory cell infiltration than the positive control. Taken together, these results suggest that eugenol and nerolidol could apply supplementary antifungal agents.

Antifungal effects of the volatile oils from Allium plants against Trichophyton species and synergism of the oils with ketoconazole

In an attempt to develop stable and safe antifungal agents from natural products (daily foodstuffs in particular), the activities of essential oils from Allium sativum for. pekinense, A. cepa, and A. fistulosum against three Trichophyton species responsible for severe mycoses in humans were investigated and compared with activity of allicin in this study. The fungistatic activities of Allium oils were evaluated by the broth dilution method and disk diffusion assay. The combined effects of Allium oils with ketoconazole were tested by the checkerboard titer test. Among the tested oils, A. sativum for. pekinense oil exhibited the strongest inhibition of growth of T. rubrum, T. erinacei, and T. soudanense with MICs (minimum inhibiting concentrations) of 64microg/ml, while the activities of A. cepa and A. fistulosum were relatively mild. The inhibiting activities of the oils on Sabouraud agar plates were dose dependent against Trichophyton species. Additionally, these oils showed significant synergistic antifungal activity when combined with ketoconazole in the checkerboard titer test and disk diffusion test.

Antifungal effects of herbal essential oils alone and in combination with ketoconazole against Trichophyton spp

AIMS

To determine the effects of herbal essential oils on Trichophyton spp. growth and to evaluate the effects of Pelargonium graveolens oil and its main components citronellol and geraniol combined with ketoconazole against Trichophyton spp.

METHODS AND RESULTS

Growth inhibition of six Trichophyton spp. by herbal essential oils was accessed and the combined effects of P. graveolens oil and its main components citronellol and geraniol were evaluated using a checkerboard microtitre assay against T. schoenleinii, T. erinacei and T. soudanense. The essential oil fraction of P. graveolens and its main components, geraniol and citronellol, exhibited strong synergism with ketoconazole against T. schoenleinii and T. soudanense, with fractional inhibitory concentration (FIC) indices in the range of 0.18-0.38.

CONCLUSIONS

The antifungal effects of ketoconazole against Trichophyton spp. are enhanced significantly by administering it in combination with the essential oil fraction of P. graveolens or its main components, because of strong synergism, especially against T. soudanense and T. schoenleinii.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combination of ketoconazole and the essential oil fraction from P. graveolens or its main components for treatment of infections caused by Trichophyton species may reduce the minimum effective dose of ketoconazole, and thus minimize the side-effects of ketoconazole.

Essential oil compounds fromAgastache rugosa as antifungal agents againstTrichophyton species

The antifungal activities of the essential oil from Agastache rugosa and its main component, estragole, combined with ketoconazole, one of the azole antibiotics commonly used to treat infections caused by Trichophyton species, were evaluated in this study. The combined effects were measured by the checkerboard microtiter and the disk diffusion tests, against T. erinacei, T. mentagrophytes, T. rubrum, T. schoenleinii and T. soudanense. Susceptibility of the five Trichophyton species to the oil alone, or ketoconazole alone, differed distinctly. The fractional inhibitory concentration indices (FICI) of ketoconazole combined with estragole or A. rugosa essential oil, against the tested Trichophyton species, were between 0.05 and 0.27, indicating synergistic effects. These drug combinations exhibited the most significant synergism against T. mentagrophytes, with FICIs of 0.05 and 0.09 for estragole and the essential oil fraction from A. rugosa, respectively. Isobolograms based on the data from checkerboard titer tests also indicated significant synergism between ketoconazole and the Agastache oil fraction or estragole, against the Trichophyton species evaluated. Trichophyton susceptibility to ketoconazole was significantly improved by combination with the Agastache rugosa oil fraction or its main component, estragole.