| Flavonoids which are widely distributed in plants can be categorized as flavonols, flavanols, flavanones, flavones, anthocyanidin and isoflavones. Quercetin (3, 3', 4', 5, 7- pentahydroxylflavone) accounts for the largest percentage of flavonol intake in the diet. Like many other flavonoids, quercetin has many health-promotion and disease-prevention benefits. However, its low solubility in water and gastric fluid leads to a low bioavailability in vivo. Lipidbased formulations, such as O/W nanoemulsions and solid lipid nanoparticles have been developed to increase the bioaccessibility of flavonoids. Modern delivery systems such as organogel or pseudo-organogel based emulsions have not yet been studied as quercetin delivery vehicles.;In this study, pseudo-organogel and pseudo-organogel based emulsion systems have been developed for oral delivery of quercetin to improve its bioaccessibility. The formation of pseudoorganogel inhibited quercetin crystallization in the oil phase. Using mixture of limonene and medium chain triglyceride (MCT) at the ratio of 2:8 (w/w), solubility of quercetin was increased by 40 times compared to quercetin in MCT at room temperature. Bioaccessibility and the extent of lipolysis were determined for the pseudo-organogel based emulsion system. After the first 30 min of digestion, the extent of lipolysis of the pseudo-organogel based emulsion (71.9 % +/- 1.2 %) was significantly higher (p<0.001) than that of the quercetin loaded oil mixture (same oil mixture as that used to form pseudo-organogel based emulsion) (54.0 % +/- 0.6 %). The percentages of bioaccessibility of quercetin in oil mixture and in pseudo-organogel based emulsion were determined to be (35.6 % +/- 0.6 %) and (49.7% +/- 5.3%) respectively, which were significantly higher than that of quercetin in water suspension (less than 3 %). With a higher and stable loading of quercetin, and the improved bioaccessibility, this pseudo-organogel based emulsion system of quercetin may have potential applications in food, cosmetic and pharmaceutical industries. |
