Antiparasitic activity of medicinal plants against protozoan fish parasite Ichthyophthirius multifiliis

The parasitic ciliate Ichthyophthirius multifiliis infests all freshwater fish species and can cause severe economic losses in aquaculture. The present study aims to evaluate the antiparasitic activity of onion (Allium cepa), sage (Salvia officinalis), menthe (Menthe spicata), garlic (Allium sativum), lavender (Lavandula officinalis) and oregano (Origanum onites) essential oils against I. multifiliis trophonts. Gas Chromatography-Mass Spectrometry (GC-MS) analyses determined these essential oils’ chemical components. The major components were dipropyl disulfide (46.15%) in onion, alpha-thujone (46.80%) in sage, carvone (48.00%) in menthe, diallyl disulfide (32.70%) in garlic, 1,8-cineole (32.65%) in lavender; carvacrol (73.00%) in oregano. I. multifilis trophonts were isolated from infected European catfish’s skin and gill arches (Silurus glanis). Then in vitro, antiparasitic assays obtained those essential oils of sage (0.50 mL L-1), lavender (0.25-, and 0.50-mL L-1), and oregano (0.1, 0.25- and 0.50-mL L-1) have been found as 100% effective against trophonts at the different concentration of after 60 min of exposure, respectively (p<0.05). In addition, onion, menthe, and garlic essential oil had effectiveness with 94%, 94%, and 92% mortalities after 60 min of exposure, respectively. These results suggested that sage, lavender, and oregano essential oils can be eco-friendly in controlling I. multifiliis trophonts.