Citrus carotenoids

Physical Methods and Physical Chemistry.—Separation and Assay Methods. A procedure for h.p.l.c. of plant pigments has been used to separate the carotenoids of spinach and of a diatom. H.p.l.c. separations of citrus carotenoids, and of retinal (67) isomers have also been reported. Carotenoid mixtures have also been separated efficiently and rapidly by centrifugal chromatography. ... 

The bright orange and yellow colors of citrus peel are due to the lipid soluble carotenoids. The more common ones in peel and juice are shown in Figure 1. Some of the first studies on citrus carotenoids were by the European workers, Zechmeister and Tuzson, in 1931 (26, 2 7, 28). They isolated p-carotene, cryptoxanthin, lutein, zeaxanthin, p-citraurin, and probably violaxanthin. In 1952, Natarajan and MacKinney (29) found phytofluene and a, p, and zeta carotenes. These studies were followed by those of Curl, who between 1953 and 1967 reported the presence of some 74 carotenoids in several citrus cultivars. 

H Yokoyama, MJ White. Citrus carotenoids. II. The structure of citranaxanthin, a new carotenoid analog. J Org Chem 30 2481-2482, 1965. 

Carotenoids and prostate cancer — Numerous epidemiological studies including prospective cohort and case-control studies have demonstrated the protective roles of lycopene, tomatoes, and tomato-derived products on prostate cancer risk other carotenoids showed no effects. " In two studies based on correlations between plasma levels or dietary intake of various carotenoids and prostate cancer risk, lycopene appeared inversely associated with prostate cancer but no association was reported for a-carotene, P-carotene, lutein, zeaxanthin, or p-cryptoxanthin. - Nevertheless, a protective role of all these carotenoids (provided by tomatoes, pumpkin, spinach, watermelon, and citrus fruits) against prostate cancer was recently reported by Jian et al. ... 

Fanciullino, A.-L. et ah. Carotenoid diversity in cultivated citrus is highly influenced by genetic factors, J. Agric. Food Chem., 54, 4397, 2006. 

Lim, S., Jung, S.K., and Jwa, M.K., Extraction of carotenoids from Citrus unshiu press cake by supercritical carbon dioxide. Food Sci. BiotechnoL, 12, 513, 2003. 

Kato, M. et al.. Accumulation of carotenoids and expression of carotenoid biosynthetic genes during maturation in citrus fruit. Plant Physiol. 134, 82, 2004. Cunningham, F.X. Jr. and Gantt, E., One ring or two Determination of ring number in carotenoids by lycopene epsilon-cyclases, Ptvc. Natl. Acad. Sci. USA 98, 2905, 2001. 

Step. In fact, citranaxanthin and reticulaxanthin, reported as natural carotenoids from citrus, are aldol condensation products formed from P-apo-8-carotenal and P-citraurin, respectively." In such samples, the extraction can be performed with MeOH and EtOAc. 

Stewart, L, and Wheaton, T.A., Conversion of 3-citraurin to reticulaxanthin and 3-apo-8 -carotenal to citranaxanthin during isolation of carotenoids from citrus. Phytochemistry, 12, 2947, 1973. 

Kato, M., H. Matsumoto et al. (2006). The role of carotenoid cleavage dioxygenases in the regulation of carotenoid profiles during maturation in citrus fruit. J. Exp. Bot. 57(10) 2153-2164. 

Rodrigo M and Zacarias L. 2007. Effect of postharvest ethylene treatment on carotenoid accumulation and the expression of carotenoid biosynthetic genes in the flavedo of orange (Citrus sinensis L. Osbeck) fruit. Postharvest Biol Technol 43 14-22. 

Another study employed an ODS column and different mobile phase composition for the measurement of carotenoids in orange juice. Citrus fruits were hand-squeezed and the juice was filtered. Aliquots of 5 ml of juice were extracted with ethyl acetate (3 X 50 ml) containing 0.004 per cent butyl hydroxytoluene (BHT). The organic phase was dried with 50 g of anhydrous sodium sulphate and the aqueous phase was mixed with 50 ml of mehanol and 100 ml of 1 M NaCl, extracted with 75 and 25 ml of ethyl acetate. The ethyl acetate fractions were combined, evaporated to dryness at 40°C and redissolved in the mobile phase. Extracts were analysed in an ODS column (250 X 4.6 mm i.d. particle size 5 jian). The mobile phase consisted of ACN-methanol-l,2-dichloroethane (60 35 5, v/v) containing 0.1 per cent BHT, 0.1 per cent triethylamine and 0.05 M of ammonium acetate. The column was not thermostated and the flow rate was 1 ml/min. Pigments were detected... 

Such a system has been used for the comprehensive 2D chromatography of proteins [9,14], synthetic polymers [16], oxygen heterocyclic fraction of cold-pressed citrus oils [22,29], carotenoids [39], triglycerides in fats and oils [18-21], pharmaceuticals [29], and acidic and phenolic compounds [27,28]. 

The first fully comprehensive coupling of NP and RP, where the previously described difficulties related to solvents immiscibility were overcome, was developed by Dugo et al. and applied to the analyses of oxygen heterocyclic components of lemon essential oils [22], Based on the configuration described in this work, other applications were developed for the analysis of carotenoids in citrus samples [48], citrus fruit extracts [29], pharmaceutical products [29], and triglycerides in fats and... 

Botanically speaking, citrus is a hesperidium, a berry with a leathery aromatic rind and a fleshy interior divided into sections. As shown by the cross section shown in Fig. 6.1, the exo carp or peel consists of an outer layer called the flavedo which contains oil glands and pigments and a white spongy inner layer called the albedo. The fleshy interior or endocarp of the fruit consists of wedge-shaped sections (segments) filled with multiple fluid-filled sacs or vesicles. These juice sacs constitute the edible portion of a citrus fruit. The cytoplasm contents provide the primary source of the citrus juice. The juice consists primarily of water, sugars, pectins, lipids, terpenes, amino acids, phenolics, carotenoids and minerals. 

Carotenoids Hippophae rhamnoides, Calendula ojjicinalis, Citrus aurantium, Ginkgo biloba, Viscum album... 

I Stewart. Provitamin A and carotenoid content of citrus juices. J Agric Food Chem 25 1132-1137, 1977. 

Among the several vitamins in this classification, only vitamin A is present in appreciable quantity as carotenoid provitamin A in citrus (38). No vitamin D has ever been reported in citrus nor any plant vitamin D precursors, such as ergosterol. Several of the sterols present in citrus fruits are reported (39, 40, 41), but they are not related to vitamin D. 

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