Anticandidal effect of Eucalyptus oil and three isolated compounds on cutaneous wound healing in rats.

OBJECTIVE: Poor healing is one of the major complications of microbial contamination of wounds. When the skin is damaged, microorganisms can quickly invade the underlying tissues and cause infections that are potentially life-threatening. As a result, effective therapies are required to handle such pathological disorders. Several bioactivities, including fungicidal and antibacterial properties, have been noted for Eucalyptus essential oils. This study aimed to investigate the effect of Eucalyptus oil (EO) and mixed oils (MO) of Eucalyptus citriodora, citronellol acetate, linalool, and α-pinene on the healing of C. albicans infected wounds in rats. MATERIALS AND METHODS: Essential oils were extracted from the fresh areal parts of Eucalyptus citriodora, Lavandula stricta, and Rosmarinus officinalis then their active compounds were chromatographically isolated and identified using GC/Ms. The in vitro antifungal activities of EO and MO were evaluated against Candida albicans using the Agar well diffusion method. Further, their effect on the healing of C. albicans infected wounds was evaluated via the excision wound rat's model. Percentages of wound contraction, epithelialization period, wound Candida load, and the histopathology of wounded tissues were evaluated to confirm the progression of wound healing. RESULTS: Results of the in vitro tests showed that MO has a potent activity against C. albicans evaluated by an inhibitory zone (IZ) diameter of 23.4 mm and a MIC value of 0.24 g/mL, compared to EO's corresponding values of 13.4 mm and 15.63 g/mL. The beneficial impacts of MO creams in improving the percentage of contraction of C. albicans contaminated wounds were better than those of EO creams. MO 10% cream showed the greatest proportion of wound contraction and epithelialization rate. The beneficial effect of MO was further confirmed by a significant reduction of the fungal load of wounds in addition to histopathological improvement compared to the NC group. CONCLUSIONS: This study suggested the potential of 10% MO cream in enhancing the healing of C. albicans infected wounds upon topical application.

Physiological and biochemical changes induced by osmolality in halotolerant aspergilli.

Aspergillus ventii and Aspergillus parasiticus halotolerant and alkali-resistant fungi were isolated from hypersaline soil of Wadi El-Natroun, Egypt by using a complex medium of high salt concentration (20% NaCl [w/v]). They were able to grow and resist the salt stress to about 20-25% NaCl and the alkaline condition tentatively to pH about 10.5. The presence of high salt concentration distorts the sporogenesis and stunt the conidiophores as well as inhibits the antimicrobial agent(s) and some extracellular hydrolytic enzymes (lipase(s) and amylase(s)). The application of some exogenous compatible solutes particularly trehalose, alpha-ketoglutarate and glycerol improves the growth and increases the resistance to salt stress (osmolality) of the two fungal isolates to about 27.5-29% NaCl (w/v). Results of the biochemical analysis (total soluble proteins, carbohydrates and lipids) PAGE and TLC of amino acid analysis support the suggestion that each species of Aspergillus has a specific mechanism for adaptation.

Influence of selenium on the efficiency of fungicide action against certain fungi.

Aspergillus funiculosus was isolated from rotted banana fruits, whereas Alternaria tenuis and Fusarium sp. were isolated from rotted tomato fruits. The isolated fungi tolerated relatively high levels of the fungicide, Dithane, up to 2560 ppm on solid medium, but grew well at 40 ppm when supplemented with liquid medium. They are able to tolerate selenite up to 2% (w/v) sodium selenite. A. funiculosus showed no growth in the presence of mixture of 2.5 ppm selenium and 20 ppm Dithane, whereas Fusarium sp. failed to grow at 2.5 ppm selenium and 10 ppm Dithane, or at 10 ppm of each. Nevertheless, Alternaria tenuis is more tolerant; it showed growth in the presence of relatively high levels of selenium and Dithane; up to 10 ppm selenium and 40 ppm Dithane, however, its growth was inhibited by the presence of a mixture of both. The results suggested new form of highly active fungicides. Selenium as an essential nutrient at such very low concentrations, as well as the application of very low concentrations of the fungicide, would certainly reduce the hazardous effect of such pollutant in the environment.