Spray-Drying Microencapsulation of Bauhinia ungulata L. var. obtusifolia Aqueous Extract Containing Phenolic Compounds: A Comparative Study Using Different Wall Materials

Pharmaceutics. 2024 Apr 2;16(4):488. doi: 10.3390/pharmaceutics16040488.


Species belonging to the Bauhinia genus, usually known as "pata-de-vaca", are popularly used to treat diabetes. Bauhinia ungulata var. obtusifolia (Ducke) Vaz is among them, of which the leaves are used as a tea for medicinal purposes in the Amazon region. A microencapsulation study of lyophilized aqueous extract from Bauhinia ungulata leaves, which contain phenolic compounds, using five different wall materials (maltodextrin DE 4-7, maltodextrin DE 11-14; β-cyclodextrin; pectin and sodium carboxymethylcellulose) is described in this paper. The microstructure, particle size distribution, thermal behavior, yield, and encapsulation efficiency were investigated and compared using different techniques. Using high-performance liquid chromatography, phenolics, and flavonoids were detected and quantified in the microparticles. The microparticles obtained with a yield and phenolics encapsulation efficiency ranging within 60-83% and 35-57%, respectively, showed a particle size distribution between 1.15 and 5.54 µm, spherical morphology, and a wrinkled surface. Among them, those prepared with sodium carboxymethylcellulose or pectin proved to be the most thermally stable. They had the highest flavonoid content (23.07 and 21.73 mg RUTE/g Extract) and total antioxidant activity by both the DPPH (376.55 and 367.86 µM TEq/g Extract) and ABTS (1085.72 and 1062.32 µM TEq/g Extract) assays. The chromatographic analyses allowed for quantification of the following substances retained by the microparticles, chlorogenic acid (1.74-1.98 mg/g Extract), p-coumaric acid (0.06-0.08 mg/g Extract), rutin (11.2-12.9 mg/g Extract), and isoquercitrin (0.49-0.53 mg/g Extract), compounds which considered to responsible for the antidiabetic property attributed to the species.

Keywords: medicinal plants; medicinal tea; microencapsulation; phenolic compounds; phytotherapy; radical scavenger.

Grants and funding

This research was funded by Coordination for the Improvement of Higher Education Personnel (CAPES, MSNR for the institutional scholarship), National Council for Scientific and Technological Development (CNPq, JOCSJ, WLRB for postdoctoral Grant nr. 200015/2023-0). Postgraduate Program in Pharmaceutical Innovation-Federal University of Para (PPGIF-UFPA), and Department of Food and Drug, University of Parma, for laboratory facilities and scholarship. Financing Agency of Studies and Projects (FINEP, WLRB for financing project, Grant nr. 1792/2010). For payment of the Publication Fee, we would like to thank the UFPA Qualified Publication Support Program (PAPQ).