Rhipicephalus microplus is responsible for considerable economic losses in tropical and subtropical regions. Plant compounds have been utilized as alternative to conventional acaricids. The objective in this study was to evaluate the effects of fixed oils extracted from seeds of Mauritia flexuosa and Mauritiella armata, palm trees typical of the Brazilian Cerrado on tick R. microplus.The fixed oils were used against engorged females and larvae by biocarrapaticidograms and larval mortality by larval pack tests (LPT). Chemical compositions of the oils were evaluated by gas chromatography using an electron impact ionization detector and showed the presence of the compounds: palmitoleic acid, linoleic acid, palmitic acid, and myristic acid. In the biocarrapaticidogram, the oil from M. flexuosa and M. armata at 5% and 10% concentrations showed efficacies > 80%. Regarding the effect of fixed oils from palm trees on R. microplus larvae, mortality above 80% was observed at all concentrations tested.These bioproducts are a promising alternative for controlling this tick and may be adapted into current integrated control methods for cattle farming.
Variations in the concentrations of plant secondary metabolites can occur due to the phenological stages of the plants, combined with environmental variations. Plants rich in tannins are used in folk medicine for different purposes. Xylopia emarginata Mart. (Anonaceae)-“Pindaíba” has been used to treat skin edema, bronchitis and malaria. We evaluated variations in condensed tannin (CTs) contents in relation to phenological variables in leaves of Xylopia emarginata during one year. The study took place in a Vereda in northern Minas Gerais State, Brazil. Monthly phenological observations as well as quantifications of the contents of condensed leaf tannins in ethanol and aqueous extracts were performed. The production of X. emarginata leaves occurred throughout the study, with greater budding and leaf fall in the dry season. Phenological observations were correlated with CT levels and climatic data of precipitation and temperature. There was a significant correlation (p < 0.05) between fruiting and CT levels in the extracts, which were higher during the dry season, 13.2% in the ethanol extract and 7.8% in the aqueous extract.
Plant-derived molluscicides have been indicated as selective and low-cost strategies for the control of Biomphalaria glabrata (Say, 1818), an intermediate host of schistosomes. This study aimed to evaluate the aqueous and ethanolic extracts of leaves of plants present in the Cerrado such as Caryocar brasiliense Camb., Ximenia americana L., Piptadenia viridiflora (Kunth) Benth., and Schinopsis brasiliensis Engl. as alternatives in the control of the mollusk B. glabrata. For this, leaves were collected from plants at the in Montes Claros-MG. Extracts at concentrations of 150, 100, 75, 50, and 25 μg/mL, a positive control containing niclosamide at 3 μg/mL, and a negative control containing dechlorinated water were used to verify the molluscicidal activity. To evaluate toxicity to non-target organisms, Artemia salina was treated with extract concentrations of 10, 100, and 1000 μg/mL. The tested aqueous and ethanolic extracts showed significant mortality within 24 h of exposure. At concentrations above 75 μg/mL, the aqueous extracts of P. viridiflora, C. brasiliense, and S. brasiliensis achieved mortality higher than 90%. Regarding ethanolic extracts, mortality above 80% was observed for all tested plants at concentrations above 50 μg/mL. No toxicity was observed against A. salina. Thus, high molluscicidal activity of ethanolic and aqueous extracts of the tested plants against adult B. glabrata was observed and no toxicity was observed against A. salina.
Introdução: Rhipicephalus (Boophilus) microplus ocasiona grandes perdas econômicas nos rebanhos bovinos e seu controle por meio de carrapaticidas sintéticos enfrenta problemas de resistência, além do risco de resíduos nos alimentos e ambiente. Objetivo: Avaliar os efeitos de extrato etanólico de folhas de Mauritia flexuosa (EEF) e Mauritiella armata (EEA) em R. microplus. Método: A ação do extrato etanólico de ambas as palmeiras (EEF e EEA) sobre os parâmetros reprodutivos de fêmeas ingurgitadas foi avaliada pelo método de biocarrapaticidograma e mortalidade das larvas pelo teste pacote de larvas (LPT). A caracterização da composição química presente nos extratos foi realizada por cromatografia gasosa (CG-EM). Resultados: O EEF e EEA foram eficientes na redução da eclodibilidade larval apresentando eficácia superior a 85% nas concentrações acima de 75 mg mL-1. Entretanto, os efeitos dos extratos na mortalidade de larvas não foram significativos em nenhuma das concentrações testadas. Catequinas foram identificadas pela CG-EM nos extratos de M. flexuosa e M. armata, sendo indicado como um importante flavonoide de ação antiparasitária. Conclusão: EEF e EEA podem interferir nos parâmetros reprodutivos de R. microplus, diminuindo a infestação larval, demonstrando ser uma alternativa promissora no controle desse ectoparasito.
O objetivo desse trabalho foi avaliar a ação carrapaticida in vitro do extrato etanólico (EE) de folhas de Xylopia emarginata Mart. com diferentes teores de taninos sobre larvas de R. microplus. Para isso, as folhas de X. emarginata foram coletas mensalmente durante o período de 12 meses para avaliar a produção de taninos através da técnica de solvólise catalisada por butanol/HCl. Para avaliar a eficácia do EE, foi realizado o teste do pacote de larvas (TPL) com leitura no intervalo de 24 horas de incubação utilizando as concentrações de 25 a 100 mg mL-1, o controle negativo contendo água destilada e o controle positivo contendo carrapaticida químico. Observou-se que o EE contendo 5,9% de teor de taninos promoveu 80,44% de mortalidade na concentração de 100 mg mL-1. O EE contendo 13,2% de teor de taninos promoveu 97,43% de mortalidade a 100 mg mL-1. Dessa forma, constatou-se alta atividade larvicida dos extratos etanólicos de folhas de X. emarginata sobre larvas de R. microplus e essa atividade pode estar relacionada aos teores de taninos.
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