In vitro activity of essential oils of free and nanostructured Melaleuca alternifolia and of terpinen-4-ol on eggs and larvae of Haemonchus contortus

Abstract

Haemonchus contortus is one of the major gastrointestinal nematodes responsible for significant economic and production losses of sheep. Diseases caused by this species lack effective anthelmintic products, and the search for new compounds to replace synthetic anthelmintics has been extensive. The present investigation assesses the in vitro activity of the essential oil of melaleuca (Melaleuca alternifolia), both free (TTO) and nanostructured (nanoTTO), and terpinen-4-ol (terp-4-ol) on eggs and larvae of H. contortus. Tests of egg hatching (EHT) and inhibition of larval migration (LMIT) were used to assess the in vitro efficacy of TTO, nanoTTO and terp-4-ol. Using EHT, at a concentration of 3.5 mg/ml, 100% inhibition occurred using TTO and terp-4-ol, with LC50 values of 0.43 and 0.63 mg/ml, and LC90 values of 1.75 mg/ml and 3.12 mg/ml, respectively. NanoTTO had lower activity, with 82.6% inhibition at the same concentration. Using LMIT, TTO and nanoTTO had a similar activity with 88.0% and 84.8% inhibition, respectively, at a concentration of 56 mg/ml. Terp-4-ol had a greater effect on larvae, with 85.7% inhibition at a concentration of 56 mg/ml and 82.4% at 3.5 mg/ml, demonstrating high activity at the lowest concentration tested. Therefore, the results indicate that all substances tested showed ovicidal and larvicidal activity against H. contortus. TTO, terp-4-ol and, mainly, nanoTTO may be targeted in in vivo studies, besides being a promising line of research into the control and treatment of veterinary important helminths.

Ovicidal and larvicidal potential of Rosmarinus officinalis to control gastrointestinal nematodes of sheep

“…The results of the essential oil effect of R. officinalis on inhibition of larval migration (ILM) show that the concentration required to obtain this activity satisfactorily is higher than that required for inhibition of hatchability (IH), the maximum of ILM (74%) was achieved in the concentration of 227.5 mg/mL, while in the HI the lowest concentration was already efficient (97.4%). Similar effect was observed with Melaleuca alternifolia, which at a concentration of 56mg/mL and 3.5mg/mL inhibited 88% larval migration and 100% hatchability of H. contortus, respectively (GRANDO et al, 2016). The concentration required to inhibit larval migration is higher than that needed to inhibit hatchability (GRANDO et al, 2016;YOSHIHARA et al, 2014;QI et al, 2015).…”

“…Similar effect was observed with Melaleuca alternifolia, which at a concentration of 56mg/mL and 3.5mg/mL inhibited 88% larval migration and 100% hatchability of H. contortus, respectively (GRANDO et al, 2016). The concentration required to inhibit larval migration is higher than that needed to inhibit hatchability (GRANDO et al, 2016;YOSHIHARA et al, 2014;QI et al, 2015). This is probably due to the fact that infecting larvae can survive in the environment exposed for long periods to deleterious weathering.…”

The use of Eucalyptus staigeriana nanoemulsion for control of sheep haemonchosis

“…Although nanostructured essential oils have been developed for use against GIN small ruminants (Ribeiro et al 2014, Grando et al 2015, validation of these products requires an assessment of AH effects for a prolonged period in sheep. The present study validated the anthelmintic effect of EsNano when combined with FAMACHA in the dry season.…”

Plant-Based Natural Products for the Discovery and Development of Novel Anthelmintics against Nematodes

“…Terpinen-4-ol from the essential oil of Melaleuca alternifolia was shown to possess ovicidal and larvicidal activity against Haemonchus contortus [73].…”