Nanoemulsion‐based delivery systems for nutraceuticals: Influence of carrier oil type on bioavailability of pterostilbene

Abstract

Food‐grade delivery systems are essential to improve bioavailability of nutraceuticals. Pterostilbene is a dietary flavonoid with various beneficial effects, but a low bioavailability. We determined the influence of nanoemulsion‐based delivery systems with different carrier oils (flaxseed oil vs. olive oil) on the bioaccessibility and bioavailability of pterostilbene. The nanoemulsions were subjected to a simulated gastrointestinal tract (GIT) which include mouth, stomach and small intestine, then the resulting micelles were subject to absorption and metabolism study in the Caco‐2 cell. The amounts of non‐conjugated and conjugated pterostilbene in the cells, apical and basolateral compartments were detected by HPLC. The bioaccessibility of pterostilbene in both nanoemulsions were significantly higher than the control (non‐encapsulated) group. The nanoemulsion containing olive oil had a higher extent of free fatty acid production in the small intestine than flaxseed oil one, it also increased trans‐enterocyte transport of pterostilbene more effectively. A decrease in the TEER values of the Caco‐2 cells for the olive oil nanoemulsions indicated that the tight junctions were loosened. Higher amounts of non‐conjugated pterostilbene were detected in all compartments than conjugated pterostilbene for both carrier oil types. Overall, our results demonstrated that nanoemulsions significantly enhanced the bioaccessibility of pterostilbene. In addition, tight junction integrity, cell permeability, and metabolism of pterostilbene were profoundly affected by carrier oil type of nanoemulsion.