Anthelmintic activity of Leucaena leucocephala protein extracts on Haemonchus contortus

Abstract

The objective of this study was to evaluate the effects of protein extracts obtained from the plant Leucaena leucocephala on the nematode parasite Haemonchus contortus. The seeds, shell and cotyledon of L. leucocephala were separated and their proteins extracted using a sodium phosphate buffer, and named as TE (total seed extract), SE (shell extract) and CE (cotyledon extract). Soluble protein content, protease, protease inhibitory and chitinase activity assays were performed. Exsheathment inhibition of H. contortus larvae were performed at concentrations of 0.6 mg mL . The effective concentration for 50% hatching inhibition (EC 50 ) was estimated by probit. Different proportions of soluble proteins, protease and chitinase were found in TE and CE. Protease inhibitory activity was detected in all extracts. The EC 50 of the CE and TE extracts were 0.48 and 0.33 mg mL -1 , respectively. No ovicidal effects on H. contortus were detected in SE extracts, and none of the protein extracts demonstrated larvicidal effects on H. contortus. We therefore conclude that protein extracts of L. leucocephala had a detrimental effect on nematode eggs, which can be correlated with the high protease and chitinase activity of these extracts.Keywords: Plant proteins, protease, protease inhibitor, chitinase. ResumoO objetivo deste estudo foi avaliar a atividade anti-helmíntica de extratos proteicos de leucena (Leucaena leucocephala) sobre Haemonchus contortus. As sementes, as cascas e os cotilédones foram moídos separadamente e as proteínas extraídas com tampão fosfato de sódio e denominados: TE (extrato total), SE (extrato casca) e CE (extrato cotilédone). O teor de proteínas, atividade proteolítica, inibitória de protease e quitinolítica dos extratos foram verificados, além da ação sobre a eclosão de ovos e desembainhamento larvar de H. contortus. A concentração efetiva para inibição de 50% da eclosão dos ovos (EC 50 ) foi calculada através do probit. Foi demonstrado que TE e CE possuem, em diferentes proporções, proteínas solúveis, protease e quitinase. Atividade inibitória de protease foi encontrada em todos os extratos. A EC 50 dos extratos CE e TE foram 0,48 e 0,33 mg de proteína mL -1 , respectivamente. O extrato SE não apresentou atividade sobre a eclosão dos ovos. Os extratos proteicos não apresentaram efeito larvicida sobre H. contortus. Conclui-se que a ação de extratos proteicos de L. leucocephala afetam negativamente a eclodibilidade dos ovos, correlacionando-se com a alta atividade de protease e quitinase dos extratos testados.Palavras-chaves: Proteínas vegetais, protease, inibidor de protease, quitinase.

Effects of selected Palestinian plants on the in vitro exsheathment of the third stage larvae of gastrointestinal nematodes

“…In our study the leaves of Leucaena have shown strong LIEA with IC 50 of 100 μg/mL. The anthelmintic activity of the plant might be attributed to the protease inhibitor activity of the plant extracts [ 68 ]. Another study conducted in 2015 [ 69 ] performed a bio-guided fractionation of an aqueous extract of Leucaena leucocephala leaves using the egg hatch assay (EHA) to identify the phytochemicals present in fresh leaves with anthelmitic activity.…”

Incorporating leucaena into goat production systems

“…Apart from substitution targeting the lower quality diet component, intake of leucaena may have been maintained due to its role as the main source of protein in the diet. The proportion of time that goats spent grazing leucaena was not affected by regrowth time for the leucaena (45-75 days), most likely because leucaena height and quality did not vary over this period (Costa et al 2015).…”

The potential of plant and fungal proteins in the control of gastrointestinal nematodes from animals

“…Thus, the cuticle and the egg membrane can be targets for attack by proteins such as proteases, lectins, chitinases, lipases and collagenases. The activity of plant proteins against Haemonchus contortus eggs has recently been suggested (SALLES et al, 2014;SOARES et al, 2015a), indicating a new direction for research aiming to develop new anthelmintic products.…”