Chemical composition and anti-Acanthamoeba activity of Melaleuca styphelioides essential oil

Acanthamoeba infections cause serious humans diseases, such as amoebic keratitis and granulomatous amoebic encephalitis. Melaleuca essential oil has been reported to be effective in treating bacterial and fungal infections. However, the anti-parasitic effects of this essential oil are not well studied. In the present study, we first characterized the composition of the essential oil, extracted from the Tunisian Melaleuca styphelioides leaves, and then tested its effect on the Acanthamoeba castellanii Neff. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the major common compounds were Caryophyllene oxide (23.42%), Spathulenol (20.5%), Isoaromadendrene epoxide (7.45%), Ledol (5.98%), α-Pinene (3.82%), Isopinocarveol (2.18%). Our data also showed that M. styphelioides essential oil inhibited the growth of Acanthamoeba with an IC₅₀ value of 69.03 ± 9.17 μg/ml. This work suggests M. styphelioides essential oil as a potential anti amoeba drug. Nevertheless, further studies are still needed to further verify the cytotoxicity of the studied oil on human macrophages and check its applicability to treat Acanthamoeba infections in vivo.