Diet effects on flavonoid bioavailability

Abstract

The anthocyanin consumption has been associated with protective effects against several cronic diseases, mainly because of their antioxidant capacity. However, many experimental studies have shown their low bioavailability although most of them were performed with isolated or parcially purified compounds, which can impair a critical evaluation of the beneficial effects when they are present in food or processed food. In previous studies in our laboratory, we observed that the increase in anthocyanin concentration in rat plasma was coincident with an increase in antioxidant activity. However, other studies have shown that probably other causes are involved, such as increased levels of endogenous antioxidant. Thus, the purpose of this project is to study the influence of food components in anthocyanin absorption and biological effects in human beings. The human absorptive pharmacokinetic of cyanidin (cy) glycosides will be compared after administration of blackberry (Rubus sp. var. Brazos) juice prepared with water or defatted milk. The effects of blackberry juice consumption on the plasma antioxidant capacity and other plasma antioxidant defenses (uric acid, glutathione and tocoferol) will be determined. Cyanidin metabolite will be also evaluated. All the results will be analyzed by Principal Component Analysis (PCA) to determine the main component responsible for the in vivo plasma antioxidant capacity. Blackberry was choice as a model because of its high anthocyanin content and low concentration of other flavonoids. Moreover, the absorptive pharmacokinetics studies will be also performed for the two cyanidin glycosides (cy-3-glucoside and cy-3-rutinoside) from wild mulberry (Morus sp.) and after this, the influence of several carbohydrates normally present in the food matrix on it. For this purpose, the intestine everted sacs will be used as a model. Other aspect to be studied is the sodium-dependent glucose transporter 1 (SGLT-1) involvement in anthocyanin absorption. Our previous results have shown that anthocyanin would in fact be absorbed through SGLT-1, but, different from other flavonoids. This absorption was not inhibited by phloridizin (PHL). In this way, our objective is to cloning and express PHL binding site of SGLT-1 to allow affinity experiments and competition assays for anthocyanin. (AU)