Avaliação da atividade anti-helmíntica do extrato etanólico de Centrosema coriaceum Benth. (Fabaceae) sobre nematoides adultos de Parapharyngodon bainae Pereira, Sousa & Souza Lima, 2010 e Physaloptera sp., parasitos de Tropidurus torquatus (Wied, 1820) (Squamata: Tropiduridae) e definição de padrões morfológicos e morfométricos para ovos e larvas de P. bainae

Abstract

The objective of this study was to verify the bioactivity of the ethanolic extract of Centrosema coriaceum leaves against gastrointestinal nematodes of adult Parapharyngodon bainae and Physaloptera sp. parasites of wild lizards Tropidurus torquatus, from an area of rocky outcrops in the state of Minas Gerais. For this, first the dried leaves of C. coriaceum were extracted by static soaking with ethanol to obtain the ethanolic extract. The extract was at concentrations of 3 mg/ml, 2 mg/ml and 1 mg/ml. They were applied in adults of the species P. bainae and Physaloptera sp., which were freshly collected from hosts separately. There was complete immobilization of parasites treated, being compared to controls after 2 hours for P. bainae and after 6 hours for Physaloptera sp., which had the mobility reduced, staying alive the parasites of the control group for both species. The nematodes exposed to concentrations of 3 mg/mL and 2 mg/mL showed significant morphological changes with complete detachment and disruption of the integument over the cuticle, when compared to the control. Transverse histological sections of the middle portion of the body of adult helminths was produced and stained with hematoxylin and eosin, from both species at concentrations of 3 mg/ml and 2 mg/ml. They showed complete detachment of hypodermis regarding cuticle compared to the control, proving the effectiveness of the extract of C. coriaceum as an anthelmintic agent, in the tested concentrations. For in vitro tests, it was further determined phases of the development of free forms of life of P. bainae until the emergence of L3 larvae, through adapted coprocultures methods, with morphological and morphometric standardization for each phase, being first reported in the literature for Oxyuridae developmental biology of wild hosts. These results suggest that the use of leaves extract to C. coriaceum in adult nematodes has anthelmintic effect and, therefore, further studies are needed to evaluate the effects on free form of life stages of P. bainae in vitro.