Antifungal activity of plant-based tinctures on Candida

To evaluate through determination of minimum inhibitory concentration (MIC) the antifungal activity of Salvia officinalis (sage), Anacardium occidentale (cashew) and Malva sylvestris (mallow) tinctures on Candida albicans (ATCC 40227), C. tropicalis (ATCC 13803) and C. krusei (ATCC 40147). Material and methods: In 96-well microplates, 100 µl of Sabouraud-Dextrose broth doubly concentrated, 100 µl of the tested tinctures and 10 µl of fungal inoculums (1.5 x 106organisms/ml) were inserted. The products were diluted from initial concentration of 100 mg/ml until 0.78 mg/ml. MIC corresponded to the lowest dilution at which there was no visible fungal growth. Nystatin (100,000 UI/ml) was used as control. Statistical analysis was performed by Kruskal-Wallis and Dunn tests (p < 0.05). Results: S. officinalis tincture did not inhibit the growth of C. albicans and C. tropicalis; MIC was 100 mg/ml for C. krusei. For A. occidentale, MIC was 100 mg/ml for C. albicans and C. krusei, and for C. tropicalis, there was no fungal inhibition. M. sylvestris tincture presented MIC at 25 mg/ml for C. krusei and 100 mg/ml for C. albicans and C. tropicalis. The best antifungal activity was showed by M. sylvestris tincture (p < 0.05). Conclusion: M. sylvestris tincture exhibited antifungal activity against all the tested strains at lower concentrations. S. officinalis tincture inhibited the action of C. krusei and A. occidentale tincture showed activity against C. albicans and C. tropicalis.