title: Chemical composition and repellency of essential oils from four medicinal plants against Ixodes ricinus nymphs (Acari: Ixodidae).
abstract: In our search for effective tick repellents from plant origin, we investigated the effect of essential oils of four medicinal and culinary plants belonging to the family Lamiaceae on nymphs of the tick Ixodes ricinus (L.). The essential oils of the dry leaves of Rosmarinus officinalis (Rosemary) (L.), Mentha spicata (Spearmint) (L.), Origanum majorana (Majoram) (L.), and Ocimum basilicum (Basil) (L.) were isolated by steam distillation and 15 microg/cm2 concentration of oils was tested against ticks in a laboratory bioassay. The oils of R. officinalis, M. spicata, and O. majorana showed strong repellency against the ticks 100, 93.2, and 84.3%, respectively, whereas O. basilicum only showed 64.5% repellency. When tested in the field, the oils of R. officinalis and M. spicata showed 68.3 and 59.4% repellency at a concentration of 6.5 microg/cm2 on the test cloths. The oils were analyzed by gas chromatography mass spectrometry and the major compounds from the most repellent oils were 1,8-cineole, camphor, linalool, 4-terpineol, borneol, and carvone.
authors.affiliation: Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Biomedical Centre, Uppsala, Sweden. hesham.el-seedi@fkog.uu.se
authors.forename: Hesham R
authors.initials: HR
authors.lastname: El-Seedi
authors.forename: Nasr S
authors.initials: NS
authors.lastname: Khalil
authors.forename: Muhammad
authors.initials: M
authors.lastname: Azeem
authors.forename: Eman A
authors.initials: EA
authors.lastname: Taher
authors.forename: Ulf
authors.initials: U
authors.lastname: Göransson
authors.forename: Katinka
authors.initials: K
authors.lastname: Pålsson
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Borg-Karlson
mesh_terms: D000818:Animals; D004534:Egypt; D008401:Gas Chromatography-Mass Spectrometry; D007302:Insect Repellents / Q000302:isolation & purification*; D018884:Ixodes; D019686:Lamiaceae / Q000737:chemistry*; D009758:Nymph; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification; D010946:Plants, Medicinal / Q000737:chemistry
chemical_list: D007302:Insect Repellents; D009822:Oils, Volatile