Cryptoxanthine, ester

BREITHAUPT D E and BAMEDIA (2001) Carotenoid esters in vegetables and fruits A screening with emphasis on P-cryptoxanthin esters. JAgric Food Chem 49(4) 2064-70. 

Breithaupt, D.E. et al.. Plasma response to a single dose of dietary (3-cryptoxanthin esters from papaya (Carica papaya L.) or non-esterified (3-cryptoxanthin in adult human subjects a comparative study, Br. J. Nutr., 90, 795, 2003. 

Neoxanthin, violaxanthin, zeaxanthin, lutein, antheraxanthin, P-cryptoxanthin, lutein monoester, antheraxanthin monoester, P-cryptoxanthin monoester, lycopene, P-carotene, violaxanthin ester, lutein diester, P-cryptoxanthin ester, P-cryptoxanthin ester, zeaxanthin diester, zeaxanthin diester, zeaxanthin diester... 

Xanthophyll esters are common in fruits and vegetables. Few data exist regarding the effect of carotenoid esterification on carotenoid bioavailability. Xanthophyll esters are readily broken in the human intestine (West and Castenmiller 1998 Breithaupt and others 2003 Faulks and Southon 2005). Chitchumroonchokchai and Failla (2006) demonstrated that hydrolysis of zeaxanthin esters increases zeaxanthin bioavailability. Wingerath and others (1995) did not find (3-cryptoxanthin esters in chylomicrons from humans fed with tangerine juice. Herbst and others (1997) demonstrated that lutein diesters are more bioavailable than free lutein. However, the question of whether the free or the esterified form is more bioavailable to humans is still an ongoing discussion. 

Wingerath T, Stahl W and Sies H. 1995. 3-Cryptoxanthin selectively increases in human chylomicrons upon ingestion of tangerine concentrate rich in 3-cryptoxanthin esters. Arch Biochem Biophys 324 385-390. 

Kimura et al. (74) recommended a procedure in which the carotenoids are dissolved in petroleum ether, an equal volume of 10% methanolic KOH is added, and the mixture is left standing overnight (about 16 h) in the dark at room temperature. This treatment caused no loss or isomerization of /3-carotene, while completely hydrolyzing /3-cryptoxanthin ester. Losses of xanthophylls could be reduced to insignificant levels by using an atmosphere of nitrogen or an antioxidant. 

Fig. 3 Normal-phase HPLC separation of Valencia orange peel carotenoids. Peaks 2 — a-cryptoxanthin esters 5 = lutein diesters 6 and 7 = violaxanthin diesters 8 = luteoxanthin diesters 15 and 16 = violaxanthin monoesters 17 = luteoxanthin monoesters. The other peaks are not identified. (From Ref. 46.)...

The degree of linkage of a compound may also affect its bioaccessibility in the gut. It is generally admitted that a compound linked with other molecules (e.g., via esterification, glycosylation, etc.) is not absorbed as well as its free form and thus it must be hydrolyzed in the gut in order to be taken up by enterocytes. Due to the presence of hydroxyl or keto groups on their molecules, the xanthophylls (lutein, zeaxanthin, and P-cryptoxanthin) are found in both free and esterified (monoester or diester) forms in nature, but few studies have been conducted to date to assess the bioavailabilities of these esters. 

In the enterocyte, provitamin A carotenoids are immediately converted to vitamin A esters. Carotenoids, vitamin A esters, and other lipophilic compounds are packaged into chylomicrons, which are secreted into lymph and then into the bloodstream. Chylomicrons are attacked by endothelial lipoprotein lipases in the bloodstream, leading to chylomicron remnants, which are taken up by the liver (van den Berg and others 2000). Carotenoids are exported from liver to various tissues by lipoproteins. Carotenes (such as (3-carotene and lycopene) are transported by low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL), whereas xanthophylls (such as lutein, zeax-anthin, and (3-cryptoxanthin) are transported by high-density lipoproteins (HDL) and LDL (Furr and Clark 1997). 

There are several provitamins A these belong to the carotenoid pigments. The most important one is P-carotene, and some of the pigments that can be derived from it are of practical importance. These are P-apo-8 -carotenal and P-apo-8 -carotenoic acid ethyl ester (Figure 9-2). Other provitamins are a- and y-carotene and cryptoxanthin. 

There are different physiological forms known as vitamins A, namely retinol (vitamin Aj) and esters, 3-dehydroretinol (vitamin A2) and esters, retinal (retinene, vitamin A aldehyde), 3-dehydroretinal (retine-2), retinoic acid, neovitamin A, and neo-b-vitamin Aj. There are active anologs and related compounds known as vitamins A, namely a-, f -, and y-carotene, neo-/3-carotene B, cryptoxanthine, myxoxanthine, torularhodin, aphanidn, and echinenone [3]. Vitamin A is susceptible to oxidation and degradation. Therefore, the control of the vitamin A level is recommended. 

Carotenoids are, as a rule, present in plants as a complex mixture. For example, the orange has more than 50 well characterized compounds, of which only those that exceed 5% of the total carotenoids are presented in Table 3.57. Hydroxy-carotinoids are often present as esters of fatty acids e. g., orange juice contains 3-hydroxy-P-carotene (cryptoxanthin) esterified with lauric, myristic and palmitic acid. The quantitative analysis of this ester fraction is used as proof of an adulteration of orange juice with mandarin juice. 

AL Sowell, DL Huff, PR Yeager, SP Caudill, EW Gunter. Retinol, a-tocopherol, lutein/zeaxanthin, P-cryptoxanthin, lycopene, a-carotene, frawi -P-carotene, and four retinyl esters in serum determined simultaneously by reversed-phase HPLC with multiwavelength detection. Clin Chem 40 411-416, 1994. 

Cryptoxanthin tatty acid esters (R = H p-cryptoxanthin R = laurate, myrisate, palmitate, stearate)... 

Figure 7.28 Flavanone conjugates, polymethoxylated flavones, f)-carotene, f5-cryptoxanthin and its fatty acid esters are found in citrus fruit.

The main dietary carotenoids are lycopene (linear, no substitutions), fl-carotene and a-carotene (ring closure at both ends, no substitutions), P-cryptoxanthin (ring closure at both ends, substitution in the 3 position), lutein (ring closure at both ends, substitutions in the 3 and 3 positions) and canthaxanthin (ring closure at both ends, [O] substitutions in the 4 and 4 positions). In some tissues, particularly flower petals, the hydroxylated carotenoids may also be present as mono- or di-acyl esters, most commonly with C16 fatty acids. Further oxidation of the terminal ring may occur to produce the mono- and di-epoxides. For an exhaustive list of carotenoids, the Key to Carotenoids (Straub 1987) is a recommended reference source. 

Another complicating factor in the intestinal mucosal cell is the partial conversion of provitamin A carotenoids (/3- and a-carotenes and cryptoxanthin) to vitamin A (primarily to retinyl esters). Therefore, in absorption studies these metabolic reactions must be accounted for in measuring intestinal transport. Nonprovitamin A carotenoids such as lycopene, lutein, and zeaxanthin are incorporated intact, although some cleavage can occur. Earlier studies on rats indicated that lycopene and /3-carotene are absorbed by passive diffusion. However, recent evidence from the kinetics of /3-carotene transport through Caco-2 cell... 

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