Antifungal Effect Of Essential Oils Research Articles

Comparison of Chemical Compositions and Antimicrobial Activities of Essential Oils from Three Conifer Trees; Pinus densiflora, Cryptomeria japonica, and Chamaecyparis obtusa

The chemical compositions, and antibacterial and antifungal effects of essential oils extracted from three coniferous species, Pinus densiflora, Cryptomeria japonica, and Chamaecyparis obtusa, were investigated. Gas chromatography mass analysis of the essential oils revealed that the major components and the percentage of each essential oil were 16.66% beta-phellandrene and 14.85% alpha-pinene in P. densiflora; 31.45% kaur-16-ene and 11.06% sabinene in C. japonica; and 18.75% bicyclo [2, 2, 1] heptan-2-ol and 17.41% 2-carene in Ch. obtusa. The antimicrobial assay by agar disc diffusion method showed that 2.2 microg of Ch. obtusa oil inhibited most effectively the growth of Escherichia coli ATCC 33312 and Klebsiella oxytoca ATCC 10031, whereas the C. japonica oil gave weak antimicrobial activity. The minimal inhibitory concentration (MIC) values for bacterial strains were in the range of 5.45-21.8 mg/ml depending on essential oils, but most Gram-negative bacteria were resistant even at 21.8 mg oil/ml. P. densiflora oil showed the most effective antifungal activity and the MIC values for Cryptococcus neoformans B42419 and Candida glabrata YFCC 062CCM 11658 were as low as 0.545 and 2.18 mg/ml, respectively. Cryp. neoformans B42419 was the most sensitive to all essential oils in the range of 0.545-2.18 mg/ml. Our data clearly showed that the essential oils from the three conifers had effective antimicrobial activity, especially against fungi.

ANTIFUNGAL PROPERTIES OF SOME MEDICINAL PLANTS AGAINST UNDESIRABLE AND MYCOTOXIN-PRODUCING FUNGI

Antifungal effects of essential oils obtained from five aromatic plants (lemon grass, brasil, sage, clove and rosemary) purchased from a local market in Egypt, were extracted to obtain the oil fraction and screened in vitro against three different pathogenic fungi, Aspergillus flavus (A. flavus), Asprgillus parasiticus (A.parasiticus) and Asprgillus ochraceus (A. ochraceus). The oil fraction from each tested plant, was carried out using water extraction and used to determine its inhibitory effects on both the fungal isolates. Also, the MIC of each oil extract and its content of the phytochemicals of phlenoles, flavonoides and terpenoids were determined. Data exhibited wide range of the inhibitory action occurred against the tested microorganisms where, bioactivity of the five plants reached its maximum using clove and its minimum using sage extracts against the tasted microorganisms. No bioactivity was observed in the treatment(s) of sage extract against the mold Asp. ochraceus. The other three extracts of rosemary, brasil and lemon grass showed roughly the same bioactivity. Also, data obtained from MIC and semi-quantitative determinations confirmed the results obtained from the antimicrobial bioactivity study. Except sage extract, the MIC of the other four extracts were ranged between 0.35-1.5 mg/ml, reached its maximum using clove and its minimum using lemon grss extracts. As well, the semi-quantitative determination of the phytochemicals of phenols, flavonides and terpenoids proved that clove extract had the highest concentration of terpenoids, while sage extract showed traces from the three phytochemicals. The other three extracts of basil, rosmary and lemon grass showed roughly the same content of the sum of the three phytochemicals. These effects against the tested microorganisms indicated the possible ability of each essential oil as a food preservative.Therefore, it is suggested that further work be performed on food to test the antifungal and antibacterial properties of these oil fractions.

Antifungal effects of essential oils from oregano and fennel onSclerotinia sclerotiorum

The antifungal effects of essential oils of oregano (Origanum syriacum var. bevanii) and fennel (Foeniculum vulgare) were evaluated against Sclerotinia sclerotiorum. Effects of the essential oils on morphological structures of hyphae and sclerotia were studied under light and scanning electron microscopes (SEM). Inhibitory effects of volatile and contact phases of the essential oils used were determined on hyphae and sclerotia. Both essential oils have a marked antifungal effect against S. sclerotiorum. Soil amendment with essential oils has significant effect on reducing sclerotial viability. Both essential oils significantly inhibited the fungal growth in soil, thereby increasing the number of surviving tomato seedling by 69.8% and 53.3%, respectively. Light and SEM observations on pathogen hyphae and sclerotia revealed considerable morphological alterations in hyphae and sclerotia. The significant reduction in the mycelial growth and germination of sclerotia would greatly reduce the pathogen inoculum source. This may influence the rate of disease development in soil. Considering the reduction in the number of diseased plants in infested soil amended with essential oils, we concluded that oregano and fennel essential oils could be used as possible bio fungicides alternative to synthetic fungicides against phytopathogenic fungi.

Antifungal effect of essential oils from some Turkish herbs against Rhizoctonia solani Kühn.

The antifungal properties of essential oils of Origanum minutiflorum (native to Turkey), O. onites, Thymbra spicata and Satureja cuneifolia were tested against six Rhizoctonia solani isolates obtained from infected seedlings from various forest nurseries in Turkey. Of the two methods to test the essential oils, the volatile assay was slightly more effective than the contact assay. While all Rhizoctonia isolates were strongly affected (>84.7) in the contact assay, the fungal isolates were completely inhibited by all the essential oils in the volatile assay. R. solani isolate Rs6 was the most sensitive, being suppressed by O. minutiflorum (100%), S. cuneifolia (100%) and T. spicata (99.6%). R. solani isolate Rs3 was also strongly inhibited by O. onites (99.1%).

Antifungal effect of essential oils on southern yellow pine

Moisture management remains the most critical factor for controlling mold growth on wood and wood products during storage, construction, and while in service. When moisture management practices fail to adequately control moisture, plant extracts demonstrating antifungal properties may provide protection for these applications. The objective of this study was to evaluate the antifungal properties of natural plant extracts, such as essential oils, for use on wood. Seven essential oils were evaluated for their ability to inhibit growth of Aspergillus niger, Trichoderma viride, and Penicillium chrysogenum on southern yellow pine (SYP) stakes that were either dip treated or exposed to vapors of the test oils. Thyme and Egyptian geranium oil inhibited growth of all test fungi for 20 weeks. Likewise, dill weed oil vapors inhibited all test fungi for at least 20 weeks. Comparison of two mold test apparatuses—Petri dish test and tank test chambers—gave similar results for thyme oil. These findings support the application of essential oils for surface treatment or vapor exposure of wood to prevent mold infestation.

Effects of Citrus sinensis (L.) Osbeck epicarp essential oil on growth and morphogenesis of Aspergillus niger (L.) Van Tieghem

Essential oils from different plant parts are known for their antimicrobial activity but the antifungal effects of essential oil from Citrus sinensis (L.) Osbeck epicarp on growth and morphogenesis of Aspergillus niger has not been observed so far. The mycelial growth was inhibited at 2.5 and 3.0 microg/ml of oil in Potato Dextrose Broth and Agar medium, respectively. These concentrations were fungicidal under the test conditions. The fungitoxicity of oil did not change even at exposure to 100 degrees C and autoclaving. The main changes observed under light and scanning electron microscopy after oil treatment were loss of cytoplasm in fungal hyphae, and budding of hyphal tip. The hyphal wall and its diameter became markedly thinner, distorted and resulted in cell wall disruption. The flattened and empty hyphal tips bifurcated into bud like structures. GC-MS studies of the oil revealed the presence of 10 chemical constituents. Limonene has been found to be major component (84.2%).

Growth inhibition and morphological alterations of Aspergillus niger by essential oils from Thymus eriocalyx and Thymus x-porlock

The antifungal effects of essential oils from Thymus eriocalyx and Thymus x-porlock were studied with special reference to the mechanism of inhibition of Aspergillus niger growth at ultrastructural level. Minimal inhibitory (MIC), minimal fungicidal (MFC) concentrations, and fungicidal kinetics of the oils were determined. Transmission electron microscopy (TEM) of A. niger exposed to MIC levels of the oils showed irreversible damage to cell wall, cell membrane and cellular organelles. The oils analyzed by GC and GC/MS led to identification of 18 and 19 components in T. eriocalyx and T. x-porlock oils respectively. The results are compared and discussed with the data in literature. It is concluded that the essential oils could be safely used as preservatives.

Antifungal effect of various essential oils against Candidaalbicans. Potentiation of antifungal action of amphotericin B by essential oil from Thymus vulgaris

The antifungal effect of the essential oil from Satureja montana L., Lavandula angustifolia Mill., Lavandula hybrida Reverchon, Syzygium aromaticum (L.) Merril and Perry, Origanum vulgare L., Rosmarinus officinalis L. and six chemotypes of Thymus vulgaris L. on Candida albicans growth were studied. The most efficiency was obtained with the essential oil from Thymus vulgaris thymol chemotype (MIC 80% = 0.016 microL/mL and Kaff = 296 microL/mL). The presence in the culture medium of essential oil from Thymus vulgaris thymol chemotype (0.01, 0.1, 0.2, 0.3 microg/mL) and amphotericin B involved a decrease of the MIC 80% of amphotericin B. In contrast, the combination of amphotericin B and low concentrations (0.00031-0.0025 microg/mL) of essential oil was antagonistic. The strongest decrease (48%) of the MIC 80% was obtained with medium containing 0.2 microL/mL of essential oil. These results signify that the essential oil of Thymus vulgaris thymol chemotype potentiates the antifungal action of amphotericin B suggesting a possible utilization of this essential oil in addition to antifungal drugs for the treatment of mycoses.

Antibacterial and antifungal effects of essential oils from coniferous trees.

Essential oils have potential biological effects, i.e., antibiotic, anticarcinogenic, and sedative effects during stress. In the present study, we investigated the antibacterial and antifungal effects of essential oils extracted from the coniferous species Pinus densiflora, Pinus koraiensis, and Chamaecyparis obtusa, because their biological activities have not been yet elucidated. The essential oils were quantified using gas chromatography and identified in gas chromatography-mass spectrometric analysis. Simultaneously, antibacterial and antifungal assays were performed using the essential oils distilled from the needles of coniferous trees. The major components and the percentage of each essential oil were: 19.33% beta-thujene in P. densiflora; 10.49% alpha-pinene in P. koraiensis; 10.88% bornyl acetate in C. obtusa. The essential oils from P. densiflora and C. obtusa have antibacterial effects, whereas essential oils from P. koraiensis and C. obtusa have antifungal effects. These results indicate that the essential oils from the three coniferous trees, which have mild antimicrobial properties, can inhibit the growth of gram-positive and gram-negative bacteria and fungi.