Avaliações botânica, química e sazonal de folhas de Pouteria guianensis (Aubl.) e estudos pré-clínicos.

• Ano de defesa: 2024
• Autor(a) principal: Rafael Christian de Matos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; FARMACIA - FACULDADE DE FARMACIA; Programa de Pós-Graduação em Ciências Farmacêuticas; UFMG
• Palavras-chave em Português: Pouteria sp.; Inflamação; Antinocicepção; Fenólicos; Cromatografia.
• Link de acesso: http://hdl.handle.net/1843/69583

The ancient use of medicinal plants for therapeutic purposes covered a wide range of pathologies, including inflammatory diseases, which is responsible for more than 50% of global deaths. In the Brazilian context, plant biodiversity offers vast potential for the development of phytotherapics, especially in genera such as Pouteria sp. which are retreat by ethnopharmacological use. Although species of this genus have been investigated for their anti-inflammatory and antinociceptive properties, phytochemical and pharmacological knowledge is still limited. The aim of this study was to conduct the histological analysis, prospecting and chemical and seasonal standardization of extracts of Pouteria guianensis Aubl. with preclinical investigation of its plant derivatives in vitro, in vivo, and ex vivo. Chemical prospecting of aqueous and hydroethanolic 80% extracts of P. guianensis leaves was carried out using colorimetric, chromatographic, and spectrometric techniques. In addition, a high-performance liquid chromatography method coupled with a diode array detector was developed and validated, and the extraction conditions of the plant derivative were optimized using a 24-type response surface (evaluating ultrasound extraction time, drug to solvent ratio, temperature and number of cycles), for subsequent pharmacological evaluations such as: anti-inflammatory and antinociceptive activities in murine models, integrity of the animals' motor capacity after administration of the extracts, antiangiogenic activity in a chorioallantoic membrane model, acute toxicity in a murine model and cytotoxicity in an Artemia salina L. model. . Histological and histochemical evaluation of the leaves was also carried out. In addition, seasonal variations in chemical and physicochemical parameters and antioxidant properties were verified. The results indicated a large amount of phenolic compounds, especially flavonoids (with extractive capacity modulated by the extraction temperature), with myricitrin being a possible major glucoside in liquid chromatographic analyses, while other classes were also identified by histochemical analyses, such as alkaloids. The botanical analyses showed a simple, glabrous epidermis with a thick cuticle with apparent undulations, as well as laticifers in the mesophyll cells, and phenolic compounds were widely distributed in the histochemistry. The developed quantitative chromatographic method was then validated. Several extracts showed antioxidant properties, which guided the selection of aqueous and hydroethanolic 80% extracts together with the compositional differentiation evaluated by chemometrics. Despite the wide seasonal variability in the physicochemical parameters of the species, the two extracts selected showed antiinflammatory and antinociceptive potential, with preservation of motor function (no alteration in hematological and biochemical tests in a murine model), additional antiangiogenic properties, and low topical toxicity in an ex vivo model. After cytotoxic analysis in A. salina, the need for studies in other models was highlighted to make cytotoxic activity more robust. In conclusion, P. guianensis extracts were chemically optimized and standardized, and preclinical trials suggested anti-inflammatory, antinociceptive, antiangiogenic, and low toxicity. Due to the novelty of the species' findings, it is necessary to investigate the mechanisms of action of the bioactive compounds to discern their therapeutic applicability.