Testing and enhancing the in vitro bioaccessibility and bioavailability of Rosmarinus officinalis extracts with a high level of antioxidant abietanes

Abstract

An antioxidant-enriched extract (RE) was obtained from rosemary (Rosmarinus officinalis) by supercritical fluid extraction to be used as an ingredient to design functional foods. The optimized mixture (42 mg RE g(-1) sunflower oil) was submitted to in vitro digestion and absorption tests (using Caco2 cells) to investigate the effect of these processes on its DPPH scavenging activity and also whether its major abietanes (tricyclic diterpenes) might be bioaccessible and bioavailable. Results indicated that supplementation of the rosemary extract with sunflower oil and lecithin (37 mg g(-1)) enhanced abietanes micellation (almost 2-fold). In vitro digestion of the mixture including RE, sunflower oil, and lecithin reduced 50% the bioaccesibility in terms of antioxidant activity. Bioavailability was 31%. It was evidenced that this activity was not due to the original levels of carnosol, carnosic acid, and methyl carnosate (which only 47% remained after digestion) but due to their derivatives and digestion products.