Acaricidal activity of eugenol based compounds against scabies mites.
BACKGROUND
Human scabies is a debilitating skin disease caused by the "itch mite" Sarcoptes scabiei. Ordinary scabies is commonly treated with topical creams such as permethrin, while crusted scabies is treated with topical creams in combination with oral ivermectin. Recent reports of acaricide tolerance in scabies endemic communities in Northern Australia have prompted efforts to better understand resistance mechanisms and to identify potential new acaricides. In this study, we screened three essential oils and four pure compounds based on eugenol for acaricidal properties.


RESULTS
Contact bioassays were performed using live permethrin-sensitive S. scabiei var suis mites harvested from pigs and permethrin-resistant S. scabiei var canis mites harvested from rabbits. Results of bioassays showed that clove oil was highly toxic against scabies mites. Nutmeg oil had moderate toxicity and ylang ylang oil was the least toxic. Eugenol, a major component of clove oil and its analogues--acetyleugenol and isoeugenol, demonstrated levels of toxicity comparable to benzyl benzoate, the positive control acaricide, killing mites within an hour of contact.


CONCLUSIONS
The acaricidal properties demonstrated by eugenol and its analogues show promise as leads for future development of alternative topical acaricides to treat scabies.
Pasay
Cielo
C
Queensland Institute of Medical Research and Australian Centre for International and Tropical Health, University of Queensland, Brisbane, Queensland, Australia. Cielo.Pasay@qimr.edu.au
Mounsey
Kate
K
Stevenson
Graeme
G
Davis
Rohan
R
Arlian
Larry
L
Morgan
Marjorie
M
Vyszenski-Moher
Diann
D
Andrews
Kathy
K
McCarthy
James
J
D056810:Acaricides / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D001681:Biological Assay; D004353:Drug Evaluation, Preclinical; D004351:Drug Resistance; D005054:Eugenol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009822:Oils, Volatile / Q000494:pharmacology; D026023:Permethrin / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D011817:Rabbits; D012520:Sarcoptes scabiei / Q000187:drug effects*; D012532:Scabies; D013552:Swine
D056810:Acaricides; D009822:Oils, Volatile; D010936:Plant Extracts; D005054:Eugenol; D026023:Permethrin