ABSTRACT Justicia calycina is a subshrub well distributed in northern South America. Despite its widespread occurrence, little is known about its anatomy and plasticity in different environments. Our study aimed to evaluate how leaf anatomical traits of J. calycina adjust in forest areas with variations in canopy openness in the Southern Amazon, Mato Grosso State, Brazil. Forest areas were: Open and Dense Ombrophilous Forest, and Seasonal Deciduous Forest (rocky outcrop). We performed anatomical measurements in leaves sampled on 10 individuals in each forest site, with the help of usual anatomy techniques. Foliar anatomy of J. calycina showed similar pattern among the studied forests, with significant difference (p<0.05) in four leaf traits among 22 studied: vascular bundle diameter, palisade parenchyma thickness, stomatal density and trichome density in adaxial epidermis. These leaf traits showed high plasticity index, with higher values in Dense Forest and in Deciduous Forest. Even though J. calycina showed overall little anatomical variation among forest types, the few attributes that differed are fundamental in the photosynthesis process. The adjustment in leaf anatomical traits under different luminosity conditions demonstrates a degree of phenotypic plasticity in the species, which contributes to its distribution in different forest phytophysiognomies in Brazilian Amazonia.

ABSTRACT Aspidosperma macrocarpon Mart. (Apocynaceae) is used in popular medicine to treat malaria and dengue. The aim of the present study was to morphoanatomically, histochemistry and phytochemically characterize A. macrocarpon young branches and leaves, seeking to indicate secondary compounds presenting medicinal potential to treat these diseases. Aspidosperma macrocarpon young branches and leaves were collected in private properties located in municipality of Alta Floresta, Mato Grosso State, Brazil. Sectional and paradermic sections were set freehand using a steelblade, were doubly stained and assembled on histological slides. The fresh material was subjected to histochemical and phytochemical tests for detection of saponins, tannins, alkaloids, flavonoids, cardiotonic glycosides, anthraquinone, steroids and terpenes. Aspidosperma macrocarpon presented glandular trichomes, cavities and secretory cells. We detected the presence of tannins, flavonoid, phenolic compounds, cardiotonic glycosides and alkaloids, which may confer antiplasmodic activity and antiviral properties to the species. As far as it is known, the present study was the first to identify aspects of the histochemical and phytochemical composition of young branches and leaves A. macrocarpon which may be associated with the popular use of this plant to treat malaria and dengue in a transition region between the Cerrado and Amazon biomes, where malaria and dengue occur endemically.

RESUMEN Aspidosperma macrocarpon Mart. (Apocynaceae) es empleada en la medicina popular para el tratamiento de la malaria y el dengue. El objetivo de este trabajo fue caracterizar morfoanatómicamente, histoquímicamente y fitoquímicamente el tronco y la lámina foliar de A. macrocarpon, buscando identificar compuestos secundarios con potencial farmacológico para el tratamiento de ambas enfermedades. Muestras de tallos verdes y hojas de A. macrocarpon fueron recolectados en propiedades particulares en el municipio de Alta Floresta, Mato Grosso, Brasil. Las secciones transversales y paradérmicas en los órganos fueron obtenidas a mano libre, con ayuda de lámina de acero, doblemente coloreadas y montadas en láminas histológicas. El material fresco fue sometido a pruebas histoquímicas y fitoquímicas para detección de saponinas, taninos, alcaloides, flavonoides, glucósidos cardiotónicos, antraquinonas, esteroides y terpenos. A. macrocarpon presenta tricomas glandulares, células secretoras y cavidades. Detectamos la presencia de taninos, flavonoides, compuestos fenólicos, glucósidos cardiotónicos y alcaloides, que pueden conferir a esta especie actividad antiplasmódica y propiedades antivirales. El presente estudio fue el primero en identificar aspectos de la composición histoquímica y fitoquímica de ramas jóvenes y hojas de A. macrocarpon que pueden estar asociados al uso popular de esa planta para el tratamiento de la malaria y del dengue en una región de transición entre los biomas Cerrado y Amazonia, donde la malaria y el dengue ocurren endémicamente.