Carotenoid-lipid interaction

During, A. et al.. Carotenoid uptake and secretion by Caco-2 cells 3-carotene isomer selectivity and carotenoid interactions, J. Lipid. Res., 43, 1086, 2002. 

McNulty, H.P., J. Byun, S.F. Lockwood, R.F. Jacob, and R.R Mason. 2007. Differential effects of carotenoids on lipid peroxidation due to membrane interactions X-ray diffraction analysis. Biochim. Biophys. Acta 1768 167-174. 

FIGURE 17.4 Interactions between carotenoids during their transport through Caco-2 cell monolayers, (a) a-C effect on 3-C transport, (b) 3-C effect on a-C transport, (c) LUT effect on P-C transport, (d) P-C effect on LUT transport, (e) LYC effect on P-C transport, and (f) P-C effect on LYC transport. Data with error bars are mean + SD obtained from three or more independent experiments ( P < 0.05 compared with the carotenoid alone). (Modified from During, A. et al., J. Lipid Res., 43, 1086, 2002.)... 

Carotenoids are highly lipophilic an active area of research concerns how carotenoids interact with and affect membrane systems (see Chapters 2 and 10). Also, the lipid solubility of these compounds has important implications for carotenoid intestinal absorption (see Chapter 17) models such as the Caco-2 cell model are being used to conduct detailed studies of carotenoid absorption/ competition for absorption (Chapter 18). The lipid solubility of these carotenoids also leads to the aggregation of carotenoids (see Chapter 3). Carotenoids aggregate both in natural and artificial systems, with implications for carotenoid excited states (see Chapter 8). This has implications for a new indication for carotenoids, namely, serving as potential materials for harnessing solar energy. 

This method is also used to measure ex vivo low-density lipoprotein (LDL) oxidation. LDL is isolated fresh from blood samples, oxidation is initiated by Cu(II) or AAPH, and peroxidation of the lipid components is followed at 234 nm for conjugated dienes (Prior and others 2005). In this specific case the procedure can be used to assess the interaction of certain antioxidant compounds, such as vitamin E, carotenoids, and retinyl stearate, exerting a protective effect on LDL (Esterbauer and others 1989). Hence, Viana and others (1996) studied the in vitro antioxidative effects of an extract rich in flavonoids. Similarly, Pearson and others (1999) assessed the ability of compounds in apple juices and extracts from fresh apple to protect LDL. Wang and Goodman (1999) examined the antioxidant properties of 26 common dietary phenolic agents in an ex vivo LDL oxidation model. Salleh and others (2002) screened 12 edible plant extracts rich in polyphenols for their potential to inhibit oxidation of LDL in vitro. Gongalves and others (2004) observed that phenolic extracts from cherry inhibited LDL oxidation in vitro in a dose-dependent manner. Yildirin and others (2007) demonstrated that grapes inhibited oxidation of human LDL at a level comparable to wine. Coinu and others (2007) studied the antioxidant properties of extracts obtained from artichoke leaves and outer bracts measured on human oxidized LDL. Milde and others (2007) showed that many phenolics, as well as carotenoids, enhance resistance to LDL oxidation. 

A number of lipids are pigments in plants. The most important group is probably carotenoids. The role of carotenoids in plant-insect interactions has been reviewed (81,82). 

B18. Bohm, V., and Bitsch, R., Intestinal absorption of lycopene from different matrices and interactions to other carotenoids, the lipid status, and the antioxidant capacity of human plasma. Ear. J.Nutr. 38,118-125 (1999). 

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