Anthelmintic effect of Cymbopogon citratus essential oil and its nanoemulsion on sheep gastrointestinal nematodes

Abstract

The anthelmintic resistance stimulated the search for strategies for controlling gastrointestinal nematodes, including the use of free essential oils or its nanoemulsion. This study evaluated the anthelmintic efficacy of Cymbopogon citratus essential oil (CcEO) and C. citratus essential oil nanoemulsion (CcEOn). Pysicochemical analyses were performed. The in vitro effect was determined using the egg hatch test (EHT) on Haemonchus contortus and in vivo effect was evaluated in sheep infected with gastrointestinal nematodes. The animals were treated with CcEO (500 mg/kg) or CcEOn (450 mg/kg) for the fecal egg count (FEC) and the determination of worm burden. The main component of CcEO was citral. The CcEO content in the nanoemulsion was 20% (v/v), and the mean particle size was 248 nm. In EHT, CcEO and CcEOn (1.25 mg/mL) inhibited larval hatching by 98.4 and 97.1%, respectively. Three animals treated with CcEO died whereas in the group treated with CcEOn one animal died. The FEC and total worm burden of the treated groups did not differ from the negative control (p>0.05). The CcEOn showed efficacy only on H. contortus (p<0.05). In conclusion, nanoencapsulation reduced toxicity and increased efficacy on H. contortus.

Essential oils fromOcimum basilicumcultivars: analysis of their composition and determination of the effect of the major compounds onHaemonchus contortuseggs

“…Inhibition of H. contortus egg hatch was previously demonstrated by the EO of one O. basilicum cultivar and associated with methyl chavicol and linalool as major compounds of the EO tested (Castro et al, 2017). In the present study, the EOs from Napoletano, Genovese and Ararat cultivars showed the highest anthelmintic activity, and they also contain methyl chavicol and linalool, as major compounds (table 1) Citral, a natural combination of the isomers neral and geranial, has been shown to be effective against several nematodes, including H. contortus, both isolated and as the major compound of EO (Hierro et al, 2006;Macedo et al, 2019). A negative correlation between the citral concentration and efficacy was found when the results of all EO cultivars were analysed (P = 0.03), whereas isolated citral showed the best activity when tested alone (table 2).…”

“…Several cultivars of O. basilicum present EOs with linalool, methyl chavicol (estragol), citral and eugenol as its main constituents, in variable concentrations (Vieira & Simon, 2000; Pascual-Villalobos & Ballesta-Acosta, 2003; Sajjadi, 2006; Martins et al ., 2010; Ottai et al ., 2012). These compounds have been shown to have anthelmintic activity, isolated or in a mixture, and they are also present, in different concentrations, in several other EOs (Katiki et al ., 2017; Ferreira et al ., 2018; Macedo et al ., 2019). The standardization of efficient cultivars or the combination of natural compounds is extremally important to human and veterinary pharmaceutical industries.…”

Chemical characterization and in vitro biological activity of Cymbopogon citratus extracts against Haemonchus spp. and Trichostrongylus spp. nematodes from sheep

“…Cymbopogon citratus essential oil nanoemulsion was also shown to inhibit 97.1% of H. contortus larvae hatching; however, it was not effective when used in live sheep infected with gastrointestinal nematodes (Macedo et al ., 2019). Moreover, C. citratus essential oil reduced the H. contortus burden by 38.5% in Meriones unguiculatus (gerbils) treated with 800 mg kg −1 (Macedo et al ., 2019). Thus, compounds in C. citratus have a lethal effect on nematodes.…”

“…Meanwhile, C. citratus essential oil or decoction inhibited H. contortus egg hatching and larval development by 90–99% at concentrations of 0.62–10 mg mL −1 (Macedo et al ., 2015). Cymbopogon citratus essential oil nanoemulsion was also shown to inhibit 97.1% of H. contortus larvae hatching; however, it was not effective when used in live sheep infected with gastrointestinal nematodes (Macedo et al ., 2019). Moreover, C. citratus essential oil reduced the H. contortus burden by 38.5% in Meriones unguiculatus (gerbils) treated with 800 mg kg −1 (Macedo et al ., 2019).…”

“…Tea/macerated leaves of C. citratus in water or food have been indicated for the medicinal treatment of helminths in dogs (Ritter et al ., 2012). The nematicidal activity of the plant has been analysed against the root-knot nematode (Oka et al ., 2000; Fabiyi et al ., 2018), pinwood nematode (Barbosa et al ., 2010) and gastrointestinal nematodes of small ruminants (Almeida et al ., 2003; Silva et al ., 2005; Macedo et al ., 2015, 2019). However, to date, no study has examined the morphological effects of C. citratus on nematodes.…”