Effect of in vitro Simulated Poultry Digestion on Bioaccessibility of Quercetin 3-D-galactoside and Antioxidants from Moringa oleifera Leaf Extracts

Abstract The use of Moringa oleifera leaves as a poultry feed has been recognized worldwide, thanks to its multi-beneficial properties for broiler quality and production. However, research on the absorption and bioaccessibility of antioxidant compounds in this material is still limited. This study aims to investigate the effect of simulated poultry digestion on the bioaccessibility of quercetin 3-D-galactoside (Q3G) from Moringa leaf extracts and its antioxidant capacity via an in vitro model. Initially, a bio-guided fractionation procedure was employed to isolate Q3G and co-occurring antioxidants from Moringa leaves using column chromatography. The identification of Q3G and major phytocompounds within the potent active samples was carried out using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/ MS). The findings revealed that Q3G is predominantly present in the ethyl acetate extract of Moringa leaves, with the highest concentration recorded as 1.3 mg/g of dry weight. Via a simulated poultry digestion model, the bioaccessibility of Q3G in the small intestinal stage was calculated to have the highest proportion of 67.1%. Significantly, the change in Q3G content was in accordance with the tendency for antioxidant activity of the Q3G-included fractions throughout the digestion. The correlation analysis suggested that Q3G has an important role in the antioxidant capacity of Moringa leaf extracts. To the best of our knowledge, this study represents a pioneering attempt to investigate the bioaccessibility and antioxidant activity of Q3G and Q3G-included extracts from Moringa leaves, utilizing an in vitro poultry digestion model. The findings establish a crucial foundation for future research and development endeavors that aim to produce antioxidant supplements enriched with Q3G from natural sources for applications in poultry production. GRAPHICAL ABSTRACT