Xanthophylls and

Algae are classified according to their colors (1) Chlorophyceae (green), (2) Rhodophyceae (red), (3) Cyanophyceae (bine-green), and (4) Pheophyceae (brown). The major pigments inclnde chlorophylls a, b, and c, P-carotene, phycocyanin, xanthophylls, and phycoerythrin. All these pigments have great potential for applications in foods, pharmacenticals, and cosmetics. 

Gregory, G.K. et ah. Quantitative analysis of lutein esters in marigold flowers (Tagetes erecta) by high performance liquid chromatography, J. Food ScL, 51, 1093, 1986. Livingston, A.L., Rapid analysis of xanthophyll and carotene in dried plant materials, J. AOAC, 69, 1017, 1986. 

Livingston, A.L., Rapid analysis of xanthophyll and carotene in dried plant materials, J. AOAC, 69, 1017, 1986. 

Gilmore, A. and H. Yamamoto (1993). Linear models relating xanthophylls and lumen acidity to non-photochemical fluorescence quenching, evidence that antheraxanthin explains zeaxanthin-independent quenching. Photosynth Res 35 67-68. 

Identifying electronic and vibrational properties of xanthophylls should provide not only structural information. Gaining information about excited state energy levels would help to design and interpret kinetic experiments, which probe molecular interactions and the energetic relationship between the xanthophylls and chlorophylls. 

Mortensen, A. and L. H. Skibsted. 1997a. Free radical transients in photobleaching of xanthophylls and carotenes. Free Rad. Res. 26 549-563. 

So far, we have focused mainly on the potential pathways of carotenoid uptake by the RPE from the choroidal blood supply. As mentioned earlier, POS contain lutein and zeaxanthin, and their distal tips are phagocytosed by the RPE. Therefore POS is another source of xanthophylls in the RPE and this pathway of carotenoid delivery and their further fate can be easily tested in cultured RPE. It has been shown that exposure of RPE cells in vitro to HDL stimulates efflux of phospholipids from phagocytosed POS out of the cell (Ishida et al., 2006). Thus it is of interest to determine whether that transport may potentially include xanthophylls and whether other types of lipoproteins may... 

Monarch epidermis. Peaks seen at 8.7, 10, and 82min are 3-hydroxy-10 -apo-P-carotenal, lutein, zeaxanthin, and P-carotene, respectively. The peak seen eluting at 22 min is the internal standard, monopropyl lutein ether, (b) The chromatogram obtained from an extract of the leaves of the milkweed plant. Peaks eluting prior to lutein are xanthophylls and epoxy xanthophylls, identified components include lutein, zeaxanthin, P-carotene, and its crT-isomer, eluting at 10, 11, 41, 77, and 79min, respectively. 

Carotenoids were discovered during the nineteenth century. Wachen in 1831 proposed the term carotene for the hydrocarbon pigment crystallized from carrot roots Berzelius called the more polar yellow pigments extracted from autumn leaves xanthophylls and Tswett separated many pigments by column chromatography and called the whole group carotenoids. ... 

Green vegetables, such as broccoli, spinach, and green beans, that contain a high diversity of xanthophylls and carotenes... 

Legally, carotenoids are divided between two E numbers. El60 covers the carotenoid hydrocarbons P-carotene, lycopene and paprika as well as the apo-carotenoids, e.g. bixin. E161 covers the xanthophylls and the carotenoids lutein, astaxanthin and canthaxanthin. 

Lutein [E161 (b)J. Lutein is one of the four most common carotenoids found in nature. The EU classifies it as E161(b). Chemically, lutein is a xanthophyll and is similar to P-carotene. Although lutein occurs in all green leafy vegetation, egg yolks and in some flowers the commercial sources are the petals of the Aztec marigold and, to a lesser extent, alfalfa. 

In spite of the obvious advantages of elevated temperature, there are examples of cases where better separation is achieved at a reduced temperature, even for simple solutes. Craft et al. [20] recently demonstrated an improved separation of P and y tocopherol at -20°C in THF/acetonitrile when compared to the ambient temperature separation of the compounds in Acetonitrile water. Bohm [21] reported the temperature dependence of the separation of a mixture of five xanthophylls and six carotenes on a C-30 column. The optimum temperature in this case was 23°C with a coelution of some peaks at temperatures below 20°C and others above 35°C. In a study using a 300 A pore C-18 column, Bohm [22] reported dramatic changes in the elution order over the temperature range -7°C to 35°C. On this column, the optimal separation was achieved at low temperatures... 

In an extract of plant material containing carotenoids (x + c = xanthophylls and carotenes) in addition to Chls, A470 (the carotenoid region) is determined as the sum of specific... 

Pigment levels given in mg/m2 leaf area and in mg/g dry weight (dw). Values measured are those from fully developed leaves in June, 2000. Pigment levels within one leaf usually vary by <3%, and pigment ratios vary by <1%. Abbreviations a + b total chlorophylls a and b x + c, xanthophylls and carotenes (total carotenoids). 

The incorporation of label from mevalonate into ABA, a sesquiterpenoid, has been demonstrated in different parts of plants ( . . 41). This indicates that ABA can be synthesized throughout the plant. In addition to the direct incorporation of three isoprene units, derived from mevalonate, into ABA, an indirect biosynthetic pathway via carotenoids has been proposed. This idea stems from the finding that xanthophylls, in particular violaxanthin, can either photochemically or enzymatically be converted to the neutral inhibitor xanthoxin (42) (Figure 3). When labeled xanthoxin was fed in the transpiration stream to bean or tomato shoots, ca. 10% was converted to ABA over an 8-hr period (43). However, the importance of the biosynthetic route to ABA via xanthophylls and xanthoxin in normal metabolism remains to be established, and most of the evidence favors the direct synthesis route via a precursor (see 2). 

Van Berkel and Zhou first tested (3-carotene with ESI positive in 1994 (van Berkel and Zhou, 1994). In this study, a doubly charged molecular ion of (3-carotene was observed as the primary species when triflur-oacetic acid was present in the solution. Van Breemen was the first to utilize ESI as an interface between HPLC and MS to analyze carotenoids (van Breemen, 1995). In this study, ESI operated in negative mode ionized xanthophylls (astaxanthin, (3-cryptoxanthin, and lutein), but did not ionize hydrocarbon carotenes (lycopene and (3-carotene). In contrast, ESI positive produced only [M" ] for all carotenoids in this study, and the addition of halogenated solvents to the post-column effluent greatly enhanced signal intensity (van Breemen, 1995). A later study by Guarantini et al. demonstrated the ability of ESI positive to produce both [M" "] and [M + H]" " for a number of xanthophylls, and these authors attributed the production of the two species to solvent system... 

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