Anatomical and histochemical characterization of stem and leaves of Bauhinia pulchella Benth. (Fabaceae)

Abstract

Bauhinia pulchella Benth. (Fabaceae), is native to Brazil and popularly known as pata-de-bode. In folk medicine, it is used to treat diabetes. Pharmacological studies have demonstrated different properties, such as cytotoxic and antioxidant, and different chemical constituents, such as essential oil, triterpenoids, steroids, among others. In order to highlight the morphological differences of the species B. pulchella from the others of the genus, and its pharmacological potential, the present study aimed to carry out the anatomical and histochemical characterization of the stem and leaves of B. pulchella. Usual methods in plant anatomy were used in the preparation of semi-permanent slides containing cross sections of the stem, petiole and leaf blade and paradermal sections of the leaf blade for analysis in light microscopy and polarized light. Histochemical tests were also performed to localize the metabolites in the stem and leaf blade. The stem of B. pulchella has a cylindrical outline, the bark is composed of 7-8 layers of cells and discontinuously distributed sclerenchyma; petiole presents flat convex contour, prominences in the adaxial region, concentric amphicrivral vascular bundle, surrounding a small concentric anfivasal intramedullary bundle, adaxially two accessory bundles and tector trichomes; leaf blade with anisocytic and tetracytic stomata on the adaxial surface and anisocytic, tetracytic and anomocytic on the abaxial surface; and midrib with plain-convex outline, 1-2 layers of collenchyma and covering trichomes. Characteristics that differ from other species of the genus Bauhinia. Alkaloids, phenolic compounds, lipophilic compounds, lignin, triterpenes, steroids and tannins were observed in the species. The results are fundamental for the pharmacobotanical standardization of the studied species.