Preparation and characterization of microcapsules loaded with polyphenols-enriched Uncaria tomentosa extract using spray-dryer technique

This work prepared and characterized microcapsule of Uncaria tomentosa (UT) in order to standardize a spray-dryer Uncaria tomentosa extract. The UT bark powder was subjected to extraction by maceration using hydro-ethanol solution. The Uncaria tomentosa extract was used to prepare the spray-dryer microcapsules UT-F1. The UT extract and microcapsules UT-F1 were submitted to chemical and physicochemical characterization tests. The phytochemical tests revealed the presence of alkaloids and phenolic compounds such as catechin. The UT extract and microcapsules UT-F1 showed high content of total phenols (28.48% ± 0.76 and 36.34% ± 0.22), high catechin content (47.95% ± 4.90 and 51.15% ± 4.20) and high antioxidant activity with IC 50 values of 5.80 and 5.03 µg cm −3 . The SEM, FTIR and TG analysis confirmed the morphology of spherical particles, the microencapsulation of the constituents of the UT extract, low moisture content, as well as stability of the microcapsules UT-F1. The DSC analysis and dissolution tests showed the technological influence of spray-dried starch combined UT extract considered water-poorly soluble resulting in vitro release (52.9%) of polyphenolic compounds from Uncaria tomentosa microcapsules. The combined use of disintegrants with a natural surfactant in the UT microcapsules has improved the release of polyphenols (catechin) from spray-dryer herbal composition reaching an equivalent release of 78.6% of catechin after 240 min. The in vitro release of microcapsules UT-F1 responds depending on the concentration of pharmaceutical excipients considered disintegrating and can easily achieve release greater than 80%. The microcapsules UT-F1 can be used as bulk material for herbal products in pharmaceutical industry.