Lipophilic pigments

The bioaccessibility of a compound can be defined as the result of complex processes occurring in the lumen of the gut to transfer the compound from a non-digested form into a potentially absorbable form. For carotenoids, these different processes include the disruption of the food matrix, the disruption of molecular linkage, the uptake in lipid droplets, and finally the formation and uptake in micelles. Thus, the bioaccessibility of carotenoids and other lipophilic pigments from foods can be characterized by the efficiency of their incorporation into the micellar fraction in the gut. The fate of a compound from its presence in food to its absorbable form is affected by many factors that must be known in order to understand and predict the efficiency of a compound s bioaccessibility and bioavailability from a certain meal. ... 

CO2 extraction has been prevalent for the isolation of essential oils and other natural lipophilic pigments like carotenoids. Hot water and superheated water extraction methods are used for analytical preparation of polar pigments. The technique is commonly referred to as subcritical water extraction because the practitioners of this approach come from SEE backgrounds. 

Because most food matrices are water soluble, many efforts were directed to the formulation of lipophilic pigments (mainly carotenoids) into water-soluble formulations (powders or gels). For hydrophilic pigments like flavonoids, polar dried microcapsules are the most popular ways to stabilize their functionality. Extracts rich in P-carotene were encapsulated using three different encapsulation techniques (spray drying, drum drying, and freeze drying)." ... 

It makes possible a selective concentration of lipophiles in the membranes. Vesicles made of n-acyl lipids or of polyprenyl phosphates extract selectively into the membrane any lipophilic substance lipophilic pigments (Nile Red), cholesterol, polyprenols, carotenoids, etc. This is particularly important for those lipophilic substances that play a role in stabilizing the membrane cholesterol, hopanoids, polyprenols, and carotenoids (Bisseret et al., 1983 Milon et al., 1986 Lazrak et uZ.,1988 Krajewski-Bertrand et al., 1990). 

During the preparation of RC I and LHC I from PS 1-200 a considerable amount of chi (31 molecules) and B-carotene (7 molecules) is selectively lost as free pigments, as can be deduced from Tab. 1. This specific loss of the most lipophilic pigments of the thylakoid membranes leads to the suggestion, that these pigments are involved in the binding of the peripheral antenna to reaction centre polypeptides and allow an efficient energy transfer from the peripheral antenna to the core antenna. 

Experiment 1 compares reversed-phase and adsorption TLC for the separation of fat-soluble chloroplast pigments from plant tissues. Experiment 2 uses silica gel TLC to examine lipophilic pigments in animal tissue. Experiment 3 uses cellulose TLC to examine water-soluble pigments (anthocyanins) in plant tissues. 

Carotenoids are widespread yellow and orange (rarely yellow-green and red) lipophilic pigments of plants, fungi, algae, microorganisms and some animals (crustaceans, fish, birds and mammals). Their annual production in nature is estimated at 1x10 tons. In plants,... 

Lipoxygenase Enzyme that oxidizes lipids and lipophilic pigments, carotenes and xanthophylls, by incorporating oxygen in double bonds yielding hydroperoxides and peroxides that later on decompose into many chemical compounds (organic acids, aldehydes, ketones, alcohols). These enzymes, generally supplemented with full-fat soybean meals, are still used to bleach wheat flours. 

Esterification increases the lipophilic character of the pigments that has been recogiuzed as an important factor for interactions with the peptide chains of proteins. The hydrolysis of this side chain results in chlorophyllides and the concomitant removal of the Mg + ion in pheophorbides. Only a Umited number of natural chlorophylls in plants and photosynthetic organisms has been described and is well... 

The purpose of this chapter is to provide an overview of our present knowledge about the health benehts of pigments, particularly their effects on chronic diseases. We examine the effects of lipophilic (carotenoids, chlorophylls) and hydrophilic pigments (anthocyanins and flavones-flavonols), and curcumin. Descriptive and mechanistic studies are reviewed in regard to common chronic diseases. 

A close relationship exists between physicochemical properties of pigment molecules and their ability to be absorbed and thus to exhibit biological functions. Carotenoids are hydrophobic molecules that require a lipophilic environment. In vivo, they are found in precise locations and orientations within biological membranes. For example, the dihydroxycarotenoids such as lutein and zeaxanthin orient themselves perpendicularly to the membrane surface as molecular rivets in order to expose their hydroxyl groups to a more polar environment. 

The degree of lipophilicity of a pigment molecule can play a major role in its bioaccessibility. Obviously, a compound with a lower lipophilic character will be... 

Natural pigments are formulated either as dyes (hydrophilic powders or lipophilic oleoresins) or lakes. 

W Wang, H Sasaki, DS Chien, VHL Lee. (1991). Lipophilicity influence on conjunctival drug penetration in the pigmented rabbit A comparison with corneal penetration. Curr Eye Res 10 571-579. 

Multipurpose tinting pastes usually contain pigment and hydrophilic solvents, sometimes some amount of water, and suitable wetting agents, which define the equilibrium between hydrophilic and lipophilic character. Conditions to be met in each case depend on the type of paste and on the method by which it is produced and also on the intended use of the coating or paint. 

Clofazimine is a dye with bactericidal activity against M. leprae and antiinflammatory properties. It is given orally, but is incompletely absorbed. Because of its high lipophilicity, it accumulates in adipose and other tissues and leaves the body only rather slowly (ti/2 - 70 d). Red-brown skin pigmentation is an unwanted effect, particularly in fair-skinned patients. 

Pitkanen, L., et al. 2005. Permeability of retinal pigment epithelium Effects of permeant molecular weight and lipophilicity. Invest Ophthalmol Vis Sci 46 641. 

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