Anthocyanins intestinal absorption

Miyazawa, T., Nakagawa, K., Kudo, M., Muraishi, K., and Someya, K., Direct intestinal absorption of red fruit anthocyanins, cyanidin-3-glucoside and cyanidin-3,5-diglucoside, into rats and humans, J. Agric. Food Chem., 47, 1083, 1999. 

Considering flavonoids, food matrix is a very important issue because it can influence the availability of the compounds to be absorbed in several ways first, the flavonoid must be liberated from the food matrix where it is inserted, and the difficulty of this process is dependent on the type of matrix second, if the food matrix has a more lipophilic environment, it can facilitate flavonoids solubiUzation and absorption. Ethanol seems to exert crucial effects on anthocyanin intestinal bioavailability, favoring its transport across intestinal epithelia. Also, interaction between different compounds may occur and interfere with absorption as well, competition or interactions for specialized transport systems are likely to occur due to the variety of molecules present in GI tract after a meal. Another important concept should be the frequency of the consumption. For anthocyanins, it is known that intestinal epithelial cells chronically exposed to anthocyanins are more prone to their own transport [33]. This is an important finding, justifying dietary recommendations, highlighting chronic consumptions of fruits and vegetables as healthy food habits. 

Studies involving individual anthocyanins revealed that their amount in plasma is generally 1 % of consumed quantities, due to limited intestinal absorption, although additional factors may contribute to the proposed low anthocyanin bioavailability, such as high rates of cellular uptake, metabolism, and excretion [36]. 

The potential mechanisms of anthocyanin glycosides absorption in the small intestine may involve a specific glucose transporter, such as SGLTl, as previously suggested for the flavonoids [74]. 

The exact site of anthocyanin absorption is not fully known recently it was suggested that the stomach is one of the preferential sites for the process in humans. Interestingly, anthocyanin glycosides are efhciently absorbed in rats (up to 25%) from both stomach " and small intestine, suggesting that anthocyanins have more than one site of absorption along the intestinal tract. 

Absorption of Anthocyanin Glycosides into the Small Intestine... 

The intestine is also a typical and important site for anthocyanin absorption. Anthocyanin absorption through the intestine was examined. The jejunum and ileum of male Wistar rats were perfused for 45 min with a phys-... 

BILBERRY, Myrtilli fructus Bilberry is the fruit of Vaccinium myrtillus, L., family Ericaceae, and contains 5-10% tannins of the catechin-type, anthocyanins, flavone glycosides and organic acids. The tannins in bilberry and in other tannin-containing drugs precipitate proteins in the epithelium of the intestine. In this way the absorption of toxic substances and secretion is diminished. This is the mode of action in the treatment of diarrhoea. 

A recent work points for the putative involvement of GLUT2 transporter in anthocyanins absorption at the intestinal level [33]. 

Faria A, Pestana D, Azevedo J, Martel F, Vd F, Azevedo I, Mateus N, Calhau C (2009) Absorption of anthocyanins through intestinal epithelial cells - putative involvement of GLUT2. Mol Nutr Food Res 53 1430-1437... 

The data presented in Figure 8.5 show that isoflavones are the best absorbed flavonoids. The maximum plasma concentrations reach about 2 p,M after an intake of 50 mg dose. For the flavonoids, in general, quercetin glucosides, flavan-3-ols and anthocyanins show maximum plasma concentrations at about 1.5 h, reflecting an absorption in the small intestine... 

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