Impact of excipient emulsions made from different types of oils on the bioavailability and metabolism of curcumin in gastrointestinal tract.

Low bioavailability currently limits the potential of curcumin as a health-promoting dietary compound. This study therefore explored the potential of excipient emulsions to improve curcumin bioavailability. Oil-in-water excipient emulsions were prepared using different types of oils: corn oil, olive oil, and medium chain triglycerides (MCT). The excipient emulsions increased the transportation rate of curcumin across the Caco-2 cell monolayer and showed ability to protect curcumin from metabolism in the enterocytes, with the olive oil-based systems exhibiting the highest efficacy. In addition, most of curcumin metabolites were present as hexahydro-curcumin (HHC) and its conjugates. Our results show that excipient emulsions can improve curcumin bioavailability by increasing its trans-enterocyte absorption and reducing cellular metabolism. Moreover, they show that these effects depend on the type of oil used to produce them. These findings have important implications for the rational design of lipid-based delivery systems to enhance the bioavailability of hydrophobic nutraceuticals like curcumin.

Enhanced lymphatic transport of bioactive lipids: cell culture study of polymethoxyflavone incorporation into chylomicrons.

Polymethoxyflavones (PMFs) are bioactive flavonoids found in citrus fruits that have been shown to have potential health promoting properties. However, their application as nutraceuticals in functional foods and beverages is currently limited due to their low water solubility and high melting point. The oral bioavailability of lipophilic compounds can be enhanced by promoting their intestinal lymphatic transport through co-administration with digestible lipids. We investigated the effects of chylomicron-mediated intestinal lymphatic transport on the bioavailability of 5-hydroxy-6,7,8,3',4'-pentamethoxylflavone (5-HPMF), one of representative PMFs in Caco-2 cells. Our results demonstrated that oleic acid and bile acid promoted secretion of chylomicrons in Caco-2 cells, with mean diameter ranged from 70 to 150 nm. The intracellular level of 5-HPMF increased 3-fold by co-incubation with the mixed micelle solution. Moreover, the basolateral level of 5-HPMF increased 3-fold due to enhanced chylomicron-mediated transport. Overall, our results demonstrated for the first time that the bioavailability of polymethoxyflavones can be enhanced by promoting their incorporation into chylomicrons.