Estudos de obtenção e caracterização de microcápsulas spray-dryer com extrato hidroalcoólico de Uncaria tomentosa

Abstract

The medicinal herbal Uncaria tomentosa has been widely used in traditional medicine, where its decoctions, prepared from its bark, are used for the treatment of various diseases and the anti-inflammatory activity is applied as the main pharmacological application. The work developed and characterized spray-dryer microcapsules of hydroalcoholic extract loaded with Uncaria tomentosa. The Uncaria tomentosa bark powder was acquired by the e-commerce in Kampo de Ervas® and subjected to extraction by infusion (using aqueous solution) or maceration (using 70oGL and 92oGL hydroethanolic solution). The hydroalcoholic extracts were partitioned using hexane and dichloromethane solvents, following the extraction method for alkaloids and, subsequently, submitted to an antibacterial activity test. The 92°GL ethanol extract was used to prepare a microcapsule composition of Uncaria tomentosa obtained by the Spray-Dryer technique. The infusion extracts, 92oGL ethanol extracts and Uncaria tomentosa microcapsule were subjected to chemical and physicochemical characterization tests by phytochemical screening tests for alkaloids, total phenols, total flavonoids, antioxidant activity tests, UV-Vis and UFLC-tests DAD, SEM test, thermal analysis tests, infrared test and dissolution tests. The characterization ethanol extract and microcapsules from Uncaria tomentosa reveal the presence of alkaloids using Dragndorff's test and phenolic compounds such as gallic acid, catechin and caffeic acid using the comparative technique of analytical standard injections by UFLC-DAD. A physicochemically stable composition of Uncaria tomentosa microcapsules was developed on a micrometric scale when analyzed by SEM, FTIR and Thermal Analysis. The dissolution tests showed Uncaria tomentosa microcapsules poorly water-soluble and pharmacotechnical adjuvants can help improve the release and absorption of active constituents by gastrointestinal fluids resulting in solid herbal compositions reaching ~ 80% release after 240 min. The Uncaria tomentosa ethanol extract and microcapsules showed antioxidant activity with IC50 values of 5.80 and 5.03 μg/mL, respectively. The Uncaria tomentosa dichloromethane fractions showed antibacterial activity against gram-negative and gram-positive bacterial strains, the UT-7 fraction obtained the best result for all strains studied, obtaining MICs below 256 μg/mL, probably due to the synergistic effect between alkaloids and phenolic compounds.