Vet Parasitol. 2016 Sep 15;228:70-76. doi: 10.1016/j.vetpar.2016.08.011. Epub 2016 Aug 13.
- 1Unidade de Biotecnologia, Universidade de Ribeirão Preto (UNAERP), Ribeirão Preto, SP, Brazil.
- 2Embrapa Pecuária Sudeste (CPPSE), São Carlos, SP, Brazil.
- 3Unidade
de Biotecnologia, Universidade de Ribeirão Preto (UNAERP), Ribeirão
Preto, SP, Brazil. Electronic address: reneusp@yahoo.com.
Abstract
Haemonchus
contortus is an important gastrointestinal parasite on sheep farms in
tropical regions. The resistance of the parasite against most
anthelmintic drugs represents a great economic problem to sheep farming
and is a major challenge that needs to be overcome. The searches for new
anthelmintic agents that act on different stages of the parasite's life
cycle are necessary for the development of new therapeutic options. The
aim of this study was to evaluate the in vitro and in vivo anthelmintic
activity of Thymus vulgaris essential oil against H. contortus and of
its main component, the monoterpene thymol. Despite the relative
ineffectiveness of the oil in the in vivo test, which may be corrected
in the future after technical improvements to increase the oil's
bioavailability, the in vitro results validated the popular use of T.
vulgaris oil as an anthelmintic agent, at least against H. contortus. In
fact, both the essential oil and thymol, which accounts for 50.22% of
the oil composition, were effective against the three main stages of H.
contortus. The oil and thymol were able to inhibit egg hatching by
96.4-100%, larval development by 90.8-100%, and larval motility by
97-100%. Similar to the positive control (levamisole 20mg/mL), the oil
and thymol completely inhibited the motility of H. contortus adults
within the first 8h of the experiment. Since thymol reproduces the
anthelmintic effects of the oil and because it is the main component of
the oil, it is reasonable to assume that thymol is the most important
compound responsible for the anthelmintic effect of T. vulgaris. These
results are of ethnopharmacological importance and may contribute to the
development of new drugs and even herbal medicines, increasing
treatment options for the farm breeding.
Copyright © 2016 Elsevier B.V. All rights reserved.
KEYWORDS:
Essential oil; Ethnoveterinary medicine; Haemonchus contortus; Small ruminants; Thymus vulgaris