Explorando a anatomia e histoquímica de Chresta pacourinoides (Mart. Ex dc.) Siniscalchi & Loeuille, Lepidaploa chalybaea (Mart. Ex dc.) H. Rob., e Melanthera latifolia (Gardner): compostos secundários e uso popular

Abstract

Plants have long been used by the population in folk medicine, being the first resource used by humanity to treat illnesses. Medicinal plants are characterized by the presence of chemical substances in their vegetative and reproductive organs; these chemical substances play an important role in the defense of plants against herbivory, in addition to being used for the production of medicines. Among them, Asteraceae stands out as the largest family of angiosperms worldwide, comprising approximately 1,600 genera and 24,000 species, making it an important group for traditional communities, who use species from this family to treat illnesses. Given this, the use and importance of plants in folk medicine and in the production of pharmaceuticals is evident, specifically in Asteraceae, which have secondary compounds that exhibit biological activity, and the scarcity of anatomical studies on the species Lepidaploa chalybaea (Mart. ex DC.) H. Rob., Chresta pacourinoides (Mart. ex DC.) Siniscalchi & Loeuille, and Melanthera latifolia (Gardner), which are already used in folk medicine and occur in Piauí. Therefore, the present work aimed to anatomically characterize the species L. chalybaea, M. latifolia, and C. pacourinoides and to identify, through histochemical tests, the presence of secondary compounds in these species, in order to associate the existence of these compounds with possible medicinal properties indicated through popular use. For this, fresh plant material was collected in the field and fixed in FNT, then freehand sections were made for anatomical analysis, and subsequently, histochemical tests were applied to the defined regions. From histochemical tests, the presence of total proteins, starch grains, and lipids was identified in C. pacourinoides, L. chalybaea, and M. latifolia; non-structural phenolic compounds, phenols, and acidic polysaccharides were found only in C. pacourinoides and M. latifolia. These compounds have medicinal action against some diseases, aiding in bioprospecting research on the studied species. Anatomical analyses revealed the presence of secretory structures such as laticifers and idioblasts, which are responsible for the secretion of chemical substances. Through this, it was possible to identify the region where the compounds are found, assisting in future anatomical and histochemical studies of these species.