Improved bioavailability of supercritical rosemary extract through encapsulation in different delivery systems after In vitro digestion

Rosmarinus officinalis L. is an aromatic plant with components known to confer health-promoting properties. The present study aimed to enhance the bioavailability of the main compounds, carnosic acid and carnosol, by encapsulation. The rosemary extracts were obtained by supercritical fluid extraction, and then different delivery systems were tested, namely oil emulsion droplets and casein micelles, native protein particles present in milk. Soybean oil in water emulsions and casein dispersions were digested in vitro with simulated gastric and intestinal fluids, and the bioavailability of the extract was tested on Caco-2 cell monolayers. The apical and basolateral compartments and the cell lysates were further analyzed for carnosic acid and carnosol content by means of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS). The encapsulation in both casein micelles and emulsion droplets significantly protected the rosemary extract from degradation during digestion, resulting in 81 and 97 % recovery of carnosic acid, respectively. This high protection rate prompted an increased bioavailability of carnosic acid and carnosol in Caco-2 monolayers, with up to 10 % carnosic acid recovered in the bioavailable fraction. Encapsulation in delivery systems like casein micelles or emulsion droplets opens new possibilities for successful incorporation of rosemary extracts in healthy food formulations with increased functionality.This project was partly funded by the Spanish Ministry of Science and Innovation (CICYT) (project: IPT-300000-2010-034), Ingredientes Saludables Mediterráneos Innovadores (INNSAMED), Comunidad Autónoma de Madrid (ALIBIRD, project S-505/AGR-0153), and the Natural Sciences and Engineering Council of Canada (NSERC). Authors are members of the COST Infogest program, and the funding for the Short-Term Scientific Mission (STSM) of E. Arranz is acknowledged.Peer Reviewe