Insecticidal activity of Fennel Essential Oil (Foeniculum vulgare) against the Head Lice, Pediculus humanus capitis

Background and Purpose: Today, Using of traditional topical anti-lice compounds has significantly reduced its effectiveness against head lice infestation. So, the tendency to use plant based on products to control this health problem is increasing. The purpose of this study was to investigate the lethal toxicity of fennel essential oil (Foeniculum vulgare Mill) against different growth stages of head lice, Pediculus humanus capitis.Materials and methods: GC-mass analysis was used to identify essential oil components. Contact filter paper bioassay was used to evaluate of fennel essential oil toxicity against nymph &adult of head lice under laboratory conditions. The exposing time was 15 min and head lice mortality was recorded after 10, 20, 30, 45 and 60 min.The immersion method was applied to the nit for 1 min and the mortality was observed until 7 days.Results: The highest components of fennel oil were Trans- anethole, α-Thujone, limonene, which consisted of 76.08, 10.37 and 5.34 % respectively. Time and concentration had a significant effect on head lice mortality means (Pvalue< 0.001). The amount of LC50 values (lethal concentration of 50%) for the adult& nymphs at 10, 20, 30, 45 and 60 minutes were 11.5, 6.4, 3.9, 3.1 and 2.5 % and LC99 values were 29.5, 15.2, 12.8, 10.8, and 7.4% respectively. The lethal time (LT50) for adult & nymph were 5.2, 8.1, 9.5, 20.5 and 45.8 minutes and LT99 were 138.6, 91.3, 23.8, 21.7, and 13.9 minutes in 2.5, 5, 10, 20 and 40% concentrations, respectively. Lethal concentrations of 50 and 99% of nit were calculated as 2.32 and 7.36% after 5 days.Conclusion: Fennel essential oil at the concentration of 15% can remove 99% of head lice (adult & nymph) in 20 minutes. It can be a potent and useful treatment for head louse control. Further research is necessary to evaluate safety of this plant compound on human health, develop an appropriate formulation for improving the pediculicidal activity.

Keywords:

Fennel , Essential Oil , Head lice , treatment