Design of nanoemulsion-based delivery systems to enhance intestinal lymphatic transport of lipophilic food bioactives: Influence of oil type

The impact of nanoemulsions containing triglycerides with different fatty acid chain lengths on the bioavailability of a highly lipophilic bioactive: 5-demethylnobiletin (5-DN) was investigated. 5-DN was encapsulated in nanoemulsions fabricated using either medium-chain triglycerides (MCT) or long-chain triglycerides (LCT). They were then subjected to in vitro digestion, and the resulting mixed micelles was applied to a Caco-2 cell model. Higher 5-DN bioaccessibility was found for the MCT-nanoemulsion (13%) than for the LCT-nanoemulsion (7%). However, only 30% 5-DN in MCT crossed the Caco-2 monolayer and 50% was metabolized, while 60% 5-DN in LCT crossed the monolayer and only 10% was metabolized. More lipid droplets and chylomicrons were also formed for the LCT nanoemulsions, indicating greater 5-DN transported through lymph. Although MCT gave a higher 5-DN bioaccessibility, the final amount of 5-DN absorbed and transported to the lymph was inferior to that of the LCT formulation.