Pistacia lentiscus essential oil and its pure active components as acaricides to control Dermanyssus gallinae (Acari: Mesostigmata)

The goal of this work was to assess the in vitro acaricidal effects of Pistacia lentiscus essential oil and its pure active components against red poultry mites Dermanyssus gallinae as an alternative to chemical acaricide (formamidines). Essential oil was obtained using hydrodistillation and then analyzed using GC-MS. The following major components were identified: alpha-pinene (20.58 %), D-Limonene (18.16 %), beta-Myrcene (15.06 %), 4Terpineol (7.68 %), caryophyllene (5.45 %) and gamma-terpinene (5.21 %). The toxicity of essential oil and its six monoterpenes were tested at concentrations ranging from 0.43 to 3.50 mg/cm(2), using contact and spraying bioassays. Toxicity was expressed as a lethal concentration (LC50 or LC90). The experiment results revealed that activity was method and concentration dependent, and the spraying method was more effective than the contact bioassay for acaricidal activity. In this bioassay, the highest mortality was observed with 4-Terpineol. The LC50 was estimated to be 0.184 mg/cm(2) for this substance, followed by alpha-pinene, the LC50 of which was estimated to be 0.203 mg/cm(2). Caryophyllene and gamma-terpinene were found less effective in controlling D. gallinae. P. lentiscus oil and its major compounds were also evaluated for anti-acetylcholinesterase (AChE) effects; 4-Terpineol was found to be the most effective AChE inhibitor with IC50 values reaching 18.73 +/- 2.83 mu g/mL. This framework pointed out the importance of the traditional use of P. lentiscus as an ecofriendly alternative against ectoparasite of veterinary importance; D. gallinae. In vivo trials should also be conducted to assure the safe use of essential oils or individual compounds and to achieve efficient acaricidal property.