Cytotoxicity and anti-Sporothrix brasiliensis activity of the Origanum majorana Linn. oil
Waller, Stefanie BressanMadrid, Isabel MartinsFerraz, VannyPicoli, TonyCleff, Marlete BrumFaria, Renata Osório deMeireles, Mário Carlos AraújoMello, João Roberto Braga de
The study aimed to evaluate the anti-Sporothrix sp. activity of the essential oil of Origanum majorana Linn. (marjoram), its chemical analysis, and its cytotoxic activity. A total of 18 fungal isolates of Sporothrix brasiliensis (n: 17) from humans, dogs and cats, and a standard strain of Sporothrix schenckii (n: 1) were tested using the broth microdilution technique (Clinical and Laboratory Standard Institute - CLSI M27-A3) and the results were expressed in minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). The MIC50 and MIC90 of itraconazole against S. brasiliensis were 2 µg/mL and 8 µg/mL, respectively, and the MFC50 and MFC90 were 2 µg/mL and >16 µg/mL, respectively, with three S. brasiliensis isolates resistant to antifungal. S. schenckii was sensitive at MIC of 1 µg/mL and MFC of 8 µg/mL. For the oil of O. majorana L., all isolates were susceptible to MIC of 2.25-9 mg/mL and MFC of 2.25-18 mg/mL. The MIC50 and MIC90 were 2.25 mg/mL and 4.5 mg/mL, respectively, and the MFC50/90 values were twice more than the MIC. Twenty-two compounds were identified by gas chromatography with a flame ionization detector (CG-FID) and 1,8-cineole and 4-terpineol were the majority. Through the colorimetric (MTT) assay, the toxicity was observed in 70-80% of VERO cells between 0.078 and 5 mg/mL. For the first time, the study demonstrated the satisfactory in vitro anti-Sporothrix sp. activity of marjoram oil and further studies are needed to ensure its safe and effective use.(AU)
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