Evaluation of antifungal and anti-ochratoxigenic activities of Salvia officinalis, Lavandula dentata and Laurus nobilis essential oils and a major monoterpene constituent 1,8-cineole against Aspergillus carbonarius

This investigation is performed to evaluate the antifungal and anti-ochratoxigenic activities of Salvia officinalis, Lavandula dentate and Laurus nobilis essential oils (EOs), and their major constituent 1,8-cineole. The evaluation of these activities was performed by two assays, contact assay with application of different concentrations of each tested EO as well as 1,8-cineole (0, 0.1, 0.2, 0.3, 0.4 and 0.5%) in Czapek Yeast Agar medium (CYA) and volatile assay by application of one concentration of each EO equal to 0.025% of CYA. The chemical composition of tested EOs was determined through gas chromatographic-mass spectrometry analysis and their antioxidant capacity was assessed by DPPH assay. Obtained results showed that L. nobilis EO exhibited better antioxidant activity (IC50 = 0.35 +/- 0.05mg/mL) than S. officinalis (IC50 = 11.12 +/- 0.09mg/mL) and L. dentate (IC50 = 14.03 +/- 0.16mg/mL) and it possessed the highest phenolic content (15.15 +/- 1.64 mg gallic acid equivalent/g EO). Statistical analyses of volatile assay showed that L. nobilis EO inhibited the growth rate much more than L. dentata and S. officinalis with a percentage equal to 47.82, 37.92 and 31.71%, respectively, and reduced the production of OTA with a percentage of 88.87%. While, on contact assay L. nobilis and L. dentata EOs exhibited a higher antifungal and anti-ochratoxigenic activities than S. officinalis, with a minimum inhibitory concentration (MIC) of about 0.3, 0.3 and 0.5%, respectively. The MIC of 1,8-cineole (0.5%) was approximately double to that of L. nobilis and L. dentata EOs. Hence, its powerful biological activities were assured by the synergism between the major component and the other existing ones.