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.

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.