Anthelmintic effect of hidroetanolic extracts from leaves Calotropis proceraagainst sheep gastrointestinal nematodes
Apocynacea, “silk flower”, phytotherapy, nematodes, veterinary
Gastrintestinal nematodes are one of the main concerns of producers regarding the sanity of small ruminants. The occurrence of anthelmintic resistance, due to the indiscriminate use, has favored investigations on the use of alternative treatments. The C. procera belonging to the family Apocynaceae is popularly known as "bombardeira", "silk flower" and "silk cotton". Native to Africa and India, the species shows good adaptability to the semi-arid conditions of the Brazilian Northeast, reports of this plant by rural producers indicate the use in farm animal feed and the relief of gastrointestinal disorders.Thus, this study aimed to evaluate the anthelmintic potential of the hydroethanolic extract of C. procera leaves by means of in vitro and in vivo assays on gastrintestinal nematodes of naturally infected sheep. The experiment was divided in stages: I. Phytochemical screening; II. Evaluation of antihelmintic activity in vitro; III. Evaluation of toxicity and IV. Clinical Trial. As a result, phytochemical screening showed the presence of secondary metabolites belonging to the flavonoids, saponins, alkaloids and phenols. Thin Layer Chromatography analysis suggested the presence of rutin, canferol and vitexin. Analysis by HPLC-ITMS / MS, identified the presence of 21 phenolic compounds. The extract of C. procera leaves had a percentage of egg hatchability greater than 90% at 24 mg/ml and 100% at concentrations higher than 36 mg/ml after 48 h of incubation. In the larval development test, more than 90% in stage rabbtoid larva at concentrations greater than 6 mg/ml of the C. procera leaves extract. The MTT assay showed that concentrations of 1 to 1.000 μg/ml of the extract showed no cytotoxicity when compared to the negative control. The acute oral toxicity test in rats showed no mortality at doses of 1.000 mg/Kg and 2.000 mg/Kg orally, as well as no significant changes in hematological and biochemical parameters in the treated groups. The results presented in the clinical trial with sheep showed a significant reduction (76%) on the 14th day in the egg count per gram of faeces after treatment when the single oral dose of 500 mg/Kg was administered. No hematological and biochemical alterations have been observed that show hepatic and renal toxicity in the animals treated with the C. procera extract. It can be concluded that this study provided evidence of the anthelmintic activity of C. procera leaf extract in gastrintestinal nematodes of naturally infected sheep.Although C. procera extract may not have a highly effective anthelmintic effect (> 90%), the reducing effect observed in this study may be of great value in integrated parasite control programs.