Isorhamnetin: A Nematocidal Flavonoid from Prosopis Laevigata Leaves Against Haemonchus Contortus Eggs and Larvae.

Edgar Jesús Delgado-Núñez,David Osvaldo Salinas-Sánchez,Agustín Olmedo-Juárez,Daniel Tapia-Maruri,Alexandre Cardoso-Taketa,Pedro Mendoza-De Gives,Alejandro Zamilpa,Ernesto Sánchez-Mendoza,Manasés González-Cortazar

doi:10.3390/biom10050773

Abstract

Haemonchus contortus affect small ruminants all over the world. Anthelmintics cause resistance, contamination, and a risk of public health. Prosopis laevigata is a plant used as a home remedy against many diseases in Mexico. This study arose from a preliminary study where a P. laevigata hydroalcoholic extract (Pl-hae) showed anthelmintic activity (aa) against H. contortus. Searching for bioactive compounds (bac) with high aa, the Pl-hae was fractioned obtaining an aqueous (Aq-F) and an ethyl acetate fraction (EtAc-F), and a flavonoid with aa identified as isorhamnetin was obtained from EtAc-F. Both fractions were in vitro assessed by the egg hatch test (eht) and larval mortality (lm) assays. The bac obtained from EtAc-F were characterised by NMR analysis. The highest aa were recorded with EtAc-F, resulting in 100% eht and 80.45% lm at 0.75 and 30 mg/mL, respectively. Alterations in eggs and larvae attributed to isorhamnetin were recorded by environmental scanning electron microscopy, confocal laser scanning and by high-resolution digital-coupled camera. This flavonoid caused 100% eht at 0.07 mg/mL after 48 h and 100% lm at 7.5 mg/mL after 72 h exposure. Isorhamnetin has promising potential as an anthelmintic against sheep haemonchosis.

Highlights

Haemonchus contortus is the most pathogenic parasitic nematode; it feeds on the blood of animals and causes severe anaemia capable of killing animals [1]
In an extend review of the literature we found little information regarding the nematocidal activity of P. laevigata extracts against H. contortus which was solely related to activity against the larvae of the parasite
The P. laevigata ethyl acetate fraction (EtAc-F) resulted in 96% in vitro larval mortality against H. contortus at only 50 mg/mL after 72 h exposure. These mortalities were similar to other results obtained with a Lysiloma acapulcensis EtAc-F, which belongs to the same taxonomic group that caused 100% mortality against H. contortus infective larvae at the same concentration and same exposure time [31]. These authors reported the same larvicidal inefficacy of L. acapulcensis Aqueous fraction (Aq-F) that we found with P. laevigata Aq-F

Summary

Introduction

Haemonchus contortus is the most pathogenic parasitic nematode; it feeds on the blood of animals and causes severe anaemia capable of killing animals [1]. In a study by López-Aroche et al [16] an important in vitro activity against H. contortus infective larvae was reported; and later on, the anthelmintic efficacy of a P. laevigata n-hexane extract reduced the H. contortus parasitic burden in gerbils that was used as an in vivo model of study [17]. This information opened new expectations to keep ahead with exploring the potential anthelmintic effect of extracts/fractions/compounds of this plant. The objectives of the present study were to evaluate the in vitro nematocidal activity of fractions obtained from a hydroalcoholic extract from P. laevigata leaves against eggs and larvae of H. contortus as well as and to identify main compounds associated with anthelmintic activity

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