Morphoanatomical characterization of vegetative organs and leaf histochemistry and phytochemistry of Laportea aestuans

In Brazil, as well as in South Africa and other regions of the world, Laportea aestuans is considered an Unconventional Food Plant and possesses significant medicinal properties. This species is native to Brazil and is the only one of its genus in the country. Due to its nutritional and medicinal importance, as well as its status as a native species, this study aims to characterize the morphoanatomy of its vegetative organs, along with a preliminary histochemical and phytochemical analysis of its leaves. To achieve this, the macroscopic characterization was performed using a caliper and a stereomicroscope. Cross-sections of the root, stem, petiole and leaf blade and paradermal sections of the leaf blade were obtained freehand and mounted on microscope slides for anatomical characterization. In histochemical and phytochemical analysis, different reagents were used according to the target metabolite. In macroscopic analysis, L. aestuans has a stem, with branches showing trichomes, leaf blade with acuminate apex, obtuse base, serrate-crenate to toothed margin, reticulate dictyodromous vein, inflorescences with the presence of trichomes on the apical and dorsal portions. Anatomically, the species presents roots with collateral vascular cylinder; stem with four to five layers of angular collenchyma, sclerenchyma caps and collateral vascular cylinder; petiole with five to six layers of angular collenchyma and bicollateral vascular bundle; hypostomatic leaf blade, with paracytic and anisocytic stomata; and central vein with angular collenchyma with four to five layers and collateral vascular bundle. All vegetative organs show drusen. There are non-glandular trichomes on the stem, petiole, and leaf blade and secretory channels only on the petiole and leaf blade. Histochemical and phytochemical tests showed the presence of different metabolites with pharmacological indications cited in the literature. Thus, this study contributes to the pharmacobotanical standardization of L. aestuans and provides important data for taxonomic, nutritional, and pharmacological studies.