Antifungal and antiproliferative activity of fractions from Mentha essential oil

Mentha spp. essential oil are known to have medicinal activity on C. albicans. In recent years fungal infections have been increasing due to a growing number of immunosuppressed and medically compromised patients. The increase in resistance to classical antifungal drugs justifies the research of natural products. In addition, the citotoxity must be evaluated to future clinical use. Objective: In the present study we investigated whether fractions from Mentha sp. essential oil are effective in prevention and treatment of C. albicans biofilm formation and their antiproliferative activity. Methods: Different parts of this plant were collected and extracted by hydrodistillation to obtain the essential oil. This oil was fractioned in dry column. Fractions F2-F3 were tested in vitro for their antifungal activity against C. albican (SC-5314) using a 96-well microtiter plate model of C. albicans biofilm formation and inhibition with a colorimetric XTT-reduction assay. After, these were evaluated for antiproliferative activity against human tumors cell lines and epithelial cells in vitro by sulphorodamine B assay with positive control (Doxorubicine). Results: Our results showed that these fractions had strong antifungal activities against C. albicans biofilm formation. They reduced the metabolic activity in preformed biofilm by 49% (F2) and 38% (F3) at 0.5mg/mL; in the inhibition biofilm formation, fraction F2 inhibited 70% at 0.062mg/mL while fraction F3 afforded 61% inhibition at 0.125mg/mL . Both fractions presented no antiproliferative activity for almost cell lines, excepted for citostatic effect against leukemia (K-562) cell line (GI50: 37.7µg/mL and 14.7µg/mL). Conclusion: These fractions exhibited selective action at microorganism. So they should be considered alternative therapeutic against biofilm-associated candidiasis. Support FAPESP (07/55972-6) NIH (NIDCR).