In vitro efficacy of five essential oils against Pediculus humanus capitis

Abstract

Treatment of head lice has relied mainly on the use of topical insecticides. Today, conventional topical pediculicides have suffered considerable loss of activity worldwide. There is increasing interest in the use of natural products such as essential oils for head louse control, and many of them are now incorporated into various over-the-counter products presented as pediculicides, often without proper evaluation. The aim of the present study was to assess the in vitro efficacy of five essential oils against adults of Pediculus humanus capitis using a contact filter paper toxicity bioassay. The chemical composition of the essential oils from wild bergamot, clove, lavender, tea tree, and Yunnan verbena was analyzed by gas chromatography-mass spectrometry. All treatments and controls were replicated three times on separate occasions over a period of 11 months. In all, 1239 living lice were collected from the scalp of 51 subjects, aged from 1 to 69 years. Clove oil, diluted either in coco oil or sunflower oil, demonstrated the best adulticidal activity, reaching > 90% mortality within 2 h in lice submitted to a 30-min contact. Yunnan verbena oil diluted in coco oil showed also a significant efficacy. Other essential oils showed a lower efficacy. The oil's major component(s) differed according to the tested oils and appeared chemically diverse. In the case of clove oil, the eugenol appeared as the main component. This study confirmed the potential interest of some of the essential oils tested, but not all, as products to include possibly in a pediculicidal formulation.

Where Are We With Human Lice? A Review of the Current State of Knowledge

“…In addition, ivermectin is the only drug currently used for oral treatment, and its highly effectiveness was clinically approved for both louse ecotypes treatment (Foucault et al, 2006;Chosidow et al, 2010), although empirically noted ivermectin resistance has started to be reported in the field in Senegal (Diatta et al, 2016). There is also growing interest in the use of natural products such as pediculicides based on plant-derived essential oils (eucalyptus oil and tea tree oil) or with a purely physical mode of action, such as dimeticone and benzyl alcohol (Meinking et al, 2010;Burgess et al, 2013;Candy et al, 2018b), but little attention has been given to their clinical evaluation for effectiveness, even though some of them are already commercialized.…”

Essential Oils as a Potential Treatment Option for Pediculosis

“…Tea tree oil was reported to be potentially effective against both head and body lice [52,54,55]. The main components of M. alternifolia are terpinen-4-ol, γ-terpinene, α-terpinene, and α-terpineol [56].…”

“…The dried flower of clove is a popular kitchen spice used in both food and ▶ PH: Pediculus humanus medicine (anesthetic, analgesic, antimicrobial, antioxidant, antiinflammatory, and anticancer agents) [61]. E. caryophyllata (clove oil) was reported to display high pediculicidal activity against head lice [40,56], which was comparable to that of commercial insecticides d-phenothrin and pyrethrum [62]. In addition, clove oil and its major component (eugenol) have repellant, acaricidal, and insecticidal activities (against Aedes and Anopheles mosquitoes, D. gallinae, and Sarcoptes scabiei) [29,63].…”

“…In addition, clove oil and its major component (eugenol) have repellant, acaricidal, and insecticidal activities (against Aedes and Anopheles mosquitoes, D. gallinae, and Sarcoptes scabiei) [29,63]. The major component of clove oil is eugenol, followed by acetyl eugenol and β-caryophyllene [56,62].…”

Volatile chemical composition of essential oil from <i>Bursera graveolens</i> (Kunth) Triana & Planch and their fumigant and repellent activities

“…It abounds in warm and dry conditions (Manivannan, 2015). There are various reports of the fumigant and repellent activities of essential oils on T. castaneum (Stefanazzi, Stadler, & Ferrero, 2011;Jaramillo-Colorado, Martelo, & Duarte, 2012;Taban, Saharkhiz, & Hooshmandi, 2017;Candy, Nicolas, Andriantsoanirina, Izri, & Durand, 2018;Hu, Wang, & Dai, 2019). However, there are no reports on B. graveolens and its components.…”