Caracterização físico-química da droga vegetal, estudo fitoquímico e farmacológico de Cnidoscolus quercifolius pohl (Euphorbiaceae)

Abstract

The richness derived from the knowledge about medicinal plants that results in the production of phytotherapics or compounds derived from secondary metabolism with pharmacological activity, resurfaces as an option for the limitations found in current therapy. However, these new products are not exempt from tests that prove their indication, effectiveness, quality and safety. Cnidoscolus quercifolius (Faveleira) is a plant characteristic of the Caatinga biome, widely spread in folk medicine due to its anti-inflammatory, analgesic, antibiotic and diuretic properties. The objective of this research was to characterize the plant drug from aerial parts, as well as to promote a phytochemical study with the research of secondary metabolites, content tests, isolation and identification of the present compounds, besides evaluating the products obtained from C. quercifolius against pharmacological activities. The physico-chemical characterization was performed by analytical methods such as thermogravimetry (TG), Fourier transform infrared (FTIR) and scanning electron microscopy coupled to dispersive energy spectroscopy (SEM/EDS); the phytochemistry sought to find the main secondary metabolites and quantify the phenolic compounds, flavonoids and tannins condensed against reference standards. The compounds were isolated using chromatographic and spectroscopic techniques such as infrared (IR), mass (MS) and 1H and 13C nuclear magnetic resonance (NMR). The pharmacological activities evaluated were: antimicrobial, hemolytic, anti-leishmania and antiproliferative. The thermal profile revealed the occurrence of three mass loss events, the FTIR the presence of functional groups such as hydroxyls, carbonyls, cyanide grouping, among others; the phytomyrographs obtained by the SEM/EDS confirmed the authenticity of the plant material and the main ions present, comparing with data from the literature. Phytochemical screening showed a positive reaction for phenols, tannins, flavonoids and steroids/triterpenoids. The quantified metabolite contents were 74.19 mg g^-1 of gallic acid equivalent total polyphenols, 16.72 mg g^-1 of flavonoids equivalent to quecertin and 48.39 mg g^-1 of catechin equivalent condensed tannins. The isolation of substances culminated in the identification of ten compounds, being four porphyrins, a cinnamic acid, a cyanogenic glycoside, a mixture of triterpenes and other steroids. The hemolytic activity test showed a low level of toxicity against human red blood cells and the other activities expressed discrete results by the methodologies adopted. The results showed that the analytical techniques allowed to characterize the plant drug, which can be useful in studies for the production of phytotherapics, besides the report of compounds identified for the first time in the family, thus contributing to its chemotaxonomy. As well as the targeting for plant utilization through the pharmacological activities performed.