Essential oil of Rosmarinus officinalis induces in vitro anthelmintic and anticoccidial effects against Haemonchus contortus and Eimeria spp. in small ruminants

Abstract

This work aimed to evaluate the valorisation of the volatile oil of "Rosmarinus officinalis L.", a spontaneously growing medicinal plant in Tunisia, by studying its chemical composition, anthelmintic and anticoccidial potentials against Eimeria spp. and Haemonchus contortus at different essential oil concentrations. The main compounds of the R. officinalis essential oil identified by GC/MS were three monoterpenes: 1,8-cineole (52.06%), α-pinene (15.35%) and camphor (7.69%). The anticoccidial activity was estimated by the inhibition percentage of the oocyte sporulation in addition to the unsporulated and degenerated Eimeria oocysts using a haemocytometer after exposure to different essential oil concentrations. The essential oil was active against Eimeria spp. oocysts of sheep at IC₅₀ = 1.82 ug/ml. Therefore, the IC₅₀ values of the anticoccidial activity of this oil examined was 1.82 mg/ml. The anthelmintic efficacy of the rosemary volatile oil against Haemonchus contortus was realised by two in vitro tests: the egg hatch assay (EHA) and the adult worm's motility assay (AWMA), by comparing this efficacy with albendazole (anthelmintic, of reference). In the egg hatch assay, the percentage of inhibition was observed at 16 mg/ml and was 73.76% after 2 days of incubation (IC₅₀ = 11.41 mg/ml) and for the adult worm's motility assay, it was 100% inhibition.

Keywords: Eimeria spp.; Haemonchus contortus; Rosmarinus officinalis; coccidia; essential oil; small ruminants.

Figure 1. Effect of the R. officinalis volatile oil concentration on the hatching eggs of Haemonchus contortus. The means with different letters (a–e) are significantly different at P < 0.05

Figure 2. Median sporulation values with the respective interquartile ranges (IQR) are provided