Ensaios iniciais sobre as antocianinas do açaí: bases para uso como corante nas cirurgias oftalmológicas
Data
2022-06-23
Orientadores
Maia, Mauricio 
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Objetivos: 1- Avaliar as alterações de cor do corante natural de antocianina de açaí (Euterpe oleracea) nos diferentes valores de pH e osmolaridades; 2- classificar e quantificar as antocianinas presentes no corante natural de açaí (Euterpe oleracea); e 3- analisar a toxicidade do corante natural de açaí (Euterpe oleracea) em modelo de coelhos. Métodos: O produto foi obtido a partir do extrato natural que contém 0,5% de antocianina, pH de 5,5 (Grupo Centroflora, Botucatu São Paulo, Brasil), liofilizado e envasado em frasco âmbar previamente esterilizado em autoclave. A osmolaridade foi ajustada em 300 mOsm e o pH ajustado para 7,00, usando uma solução diluída de corante de antocianina em solução de tampão fosfato PBS (Ophthalmos, São Paulo, Brasil), e os valores de pH foram ajustados para uma solução tamponada com hidróxido de sódio e após as modificações químicas necessárias, foram obtidos solução de concentração de 0,5%, com coloração roxa, pH 7,06 e osmolaridade 304 mOsm, demonstrando grande afinidade pela MLI em 12 olhos cadavéricos testados. Cinco padrões primários de moléculas de antocianina de açaí (Euterpe oleracea) adquiridas da empresa ChromaDex® foram utilizadas como comparativo para a solução manipulada: taxifolina 25mg, orientina 25mg, isovitexina 25mg, homo-orientina 25mg e cianidina-3-0-glucosídeo 25mg. As concentrações de antocianinas na amostra foram quantificadas e qualificadas por cromatografia líquida de alta eficiência (HPLC) e espectrometria de massas (EM). Injeções intravítreas em coelhos nas concentrações de 10%, 25% e 35% do corante natural de açaí (Euterpe oleracea) foram realizadas, e os olhos controle receberam solução salina balanceada (SSB). Exames de eletrorretinografia (ERG), retinografia, angiofluoresceinografia (AFG), tomografia de coerência óptica (OCT), microscopia óptica (LM) e microscopia eletrônica de transmissão (MET) foram executados: antes das injeções intravítreas, bem como em 24 horas e 7 dias. Resultados: O corante ajustado à osmolaridade de 300 mOsm e o pH ajustado de 7,00 resultaram em coloração roxa. As cinco principais antocianinas descritas em literatura estão presentes no corante natural de açaí (Euterpe oleracea), sendo a cianidina-3-0-glucosídeo a mais prevalente. O uso do corante foi seguro nas concentrações de 10% e 25% no estudo em coelhos por não apresentar alteração morfológica de toxicidade significante; já na concentração de 35%, anormalidades compatíveis com toxicidade incipiente foram observadas. Conclusões: O corante extraído do fruto do açaí resultou em coloração roxa e após ajustes físico-químicos de osmolaridade (304 mOsm) e pH (7,06) adequados para uso na cromovitrectomia, apresentou boa afinidade pela MLI em olhos cadavéricos e, portanto, pode ser útil para cirurgia vitreorretiniana A cianidina-3-0-glucosídeo foi a antocianina mais encontrada. A concentração das antocianinas a 10% e 25% foram seguras em olhos de coelhos.
Objectives: 1- to evaluate the acai fruit (Euterpe oleracea) at different pH-values and osmolarities; 2- to classify and quantify the anthocyanins at the natural acai (Euterpe oleracea) dye; and 3- to analyse the safety profile of the acai (Euterpe oleracea) dye in rabbit model. Methods: The product was obtained from the natural extract that contains 0.5% of anthocyanins, pH = 5.5 and was lyophilized and packaged in ambar flasks previously sterilized in the autoclave (Etno Brasil, São Paulo, Brazil). The osmolarity was adjusted in 300 mOsm and pH = 7.00 using a diluted solution of the anthoacyanin dye and phosphate buffer (PSB Ophthalmos, São Paulo, Brazil); pH-values were adjusted with sodium hydroxide and after the necessary chemical modifications, a solution with a concentration of 0.5% was obtained, with a purple color, pH 7.06 and osmolarity 304 mOsm, demonstrating great affinity for ILM in 12 cadaveric eyes tested. Five samples of anthocyanins molecules from acai fruit (Euterpe oleracea) acquired from ChromaDex® company (São Paulo, Brazil) were used as pattern at 25mg: taxifolin, orientin, isovitexin, homoorientin and cyanidin-3-0-glucoside. The concentrations of anthocyanins were quantified and qualified by high performance liquid chromatography (HPLC) and mass spectrophotometry (MS). Intravitreal injections in rabbits at 10%, 25% and 35% of the natural acai dye (Euterpe oleracea) were performed and control-eyes were submitted to balanced saline solution (BSS). Electroretinography (ERG), fundus photographs, fluorescein angiogram (AF), optical choherence tomography (OCT), light microscopy (LM) and transmission electron microscopy (MET) were performed at baseline as well as 24 hours and 7 days. Results: The dye that had the osmolarity adjusted to 300 mOsm and pH = 7.00 resulted in purple color. The five main anthocyanins described at the literature were also present at the natural acai dye (Euterpe oleracea), and the cyanidine-3-0-glucoside was the most prevalent one. The use of the dye was safe at concentrations of 10% and 25% at the rabbit study; however, at 35%, abnormalities suggestive of toxicity were observed. Conclusions: The dye extracted from the acai fruit resulted in purple color. The cyanidine-3-0-glucoside was the most prevalent anthocyanin. The anthocyanins concentrations of 10% and 25% were safe in rabbit eyes.
Objectives: 1- to evaluate the acai fruit (Euterpe oleracea) at different pH-values and osmolarities; 2- to classify and quantify the anthocyanins at the natural acai (Euterpe oleracea) dye; and 3- to analyse the safety profile of the acai (Euterpe oleracea) dye in rabbit model. Methods: The product was obtained from the natural extract that contains 0.5% of anthocyanins, pH = 5.5 and was lyophilized and packaged in ambar flasks previously sterilized in the autoclave (Etno Brasil, São Paulo, Brazil). The osmolarity was adjusted in 300 mOsm and pH = 7.00 using a diluted solution of the anthoacyanin dye and phosphate buffer (PSB Ophthalmos, São Paulo, Brazil); pH-values were adjusted with sodium hydroxide and after the necessary chemical modifications, a solution with a concentration of 0.5% was obtained, with a purple color, pH 7.06 and osmolarity 304 mOsm, demonstrating great affinity for ILM in 12 cadaveric eyes tested. Five samples of anthocyanins molecules from acai fruit (Euterpe oleracea) acquired from ChromaDex® company (São Paulo, Brazil) were used as pattern at 25mg: taxifolin, orientin, isovitexin, homoorientin and cyanidin-3-0-glucoside. The concentrations of anthocyanins were quantified and qualified by high performance liquid chromatography (HPLC) and mass spectrophotometry (MS). Intravitreal injections in rabbits at 10%, 25% and 35% of the natural acai dye (Euterpe oleracea) were performed and control-eyes were submitted to balanced saline solution (BSS). Electroretinography (ERG), fundus photographs, fluorescein angiogram (AF), optical choherence tomography (OCT), light microscopy (LM) and transmission electron microscopy (MET) were performed at baseline as well as 24 hours and 7 days. Results: The dye that had the osmolarity adjusted to 300 mOsm and pH = 7.00 resulted in purple color. The five main anthocyanins described at the literature were also present at the natural acai dye (Euterpe oleracea), and the cyanidine-3-0-glucoside was the most prevalent one. The use of the dye was safe at concentrations of 10% and 25% at the rabbit study; however, at 35%, abnormalities suggestive of toxicity were observed. Conclusions: The dye extracted from the acai fruit resulted in purple color. The cyanidine-3-0-glucoside was the most prevalent anthocyanin. The anthocyanins concentrations of 10% and 25% were safe in rabbit eyes.