Estudo farmacobotânico de Ageratum conyzoides e uma revisão de suas atividades biológicas.

Abstract

Ageratum conyzoides is a species of Asteraceae native to Brazil, popularly known as "mentrasto" or "catinga de bode", whose leaves are used in popular medicine in the treatment of ovarian inflammation, amenorrhea, and the infusion of its aerial parts indicated in the treatment of joint pain (arthritis, arthrosis) and rheumatism. In this work a pharmacobotanical and histochemical study of Ageratum conyzoides leaves and stem, and a review of its biological activities were carried out, aiming to contribute the characterization and quality control of its ethnodrugs. The botanical material was collected in a caatinga biome in the city of Cuité-PB. Macroscopic and microscopic analyzes of leaves and stem were performed on fresh and hydrated samples of herborized material. For the anatomical study, paradermal (leaves) and cross sections of leaves and stem were performed, and later clarified and stained with safranin and/or astrablue, observed and photographed under an optical microscope. Ageratum conyzoides is a sub-shrub herb, with opposite leaves, oval leaf blade, obtuse apex and base; the stem is cylindrical, with green to brown branches. Regarding anatomy, the leaves have a hypostomatic epidermis, with anomocytic and anisocytic stomata, sinuous anticlinal walls, hairy inductor with tector and glandular trichomes, dorsiventral mesophyll, vascular system formed by 1-9 collateral bundles in the main vein, and five bundles in the petiole. Crystalliferous idioblasts and secretory channels occur in the petiole. The stem has a circular outline, with an eustelic structure. Histochemical tests showed the presence of cutin and lignin, as well as demonstrated a positive reaction to starch and phenolic compounds. The pharmacological activities reported that the species is promising for the development of herbal medicines. The anatomy of leaf epidermis and vascular organization in the stem were the main distinguishing characters for recognizing A. conyzoides.