1,2-Epoxy lycopene

Although several acyclic epoxycarotenoids occur naturally, only two, namely 1,2-epoxy-lycopene (217) and 1,2-epoxy- -carotene (218), have been synthesized. 

There are basically two types of carotenoids those that contain one or more oxygen atoms are known as xanthophylls those that contain hydrocarbons are known as carotenes. Common oxygen substituents are the hydroxy (as in p-cryptoxanthin), keto (as in canthaxanthin), epoxy (as in violaxanthin), and aldehyde (as in p-citraurin) groups. Both types of carotenoids may be acyclic (no ring, e.g., lycopene), monocyclic (one ring, e.g., y-carotene), or dicyclic (two rings, e.g., a- and p-carotene). In nature, carotenoids exist primarily in the more stable all-trans (or all-E) forms, but small amounts of cis (or Z) isomers do occur. - ... 

Fig. 2.23. Reversed-phase gradient HPLC profiles of carotenoids in human plasma. A human volunteer was given an oral dose of 5,6-epoxy-/l-carotene (9.1 /imol). Plasma was analysed for carotenoids before (a) and 6h after (b) the oral dose. Peak identification 1, bilirubin 2, lutein 3, zeaxanthin 4, /1-cryptoxanthin 5, 5,6-epoxy-/l-carotene 6, lycopene 7, /1-carotene. The detection wavelength was 445 nm. AU, absorbance unit. Reprinted with permission from A. B. Barua [50],...

The term carotenoids designates a group of structurally related colorants that are mainly found in plants. At present, more than 600 carotenoids have been identified. Their basic structure is a symmetrical tetraterpene skeleton, formed by head-to-tail condensation of two 20-carbon units. (Formula 9.1). Based on their composition, carotenoids are subdivided into two groups carotenes, which contain only carbon and hydrogen atoms, e.g., a-, P-, and y-carotenes and lycopene (Formulae 9.2-9.4) and xanthophylls — oxocarotenoids — which contain at least one oxygen function, such as hydroxy, keto, or epoxy groups (Formulae 9.5-9.9). 

Carotenoids. Carotenoids are fat-soluble pigments comprised of isoprene units and, in plants, are generally associated with membranes (30). Carotenoids are generally classified as either carotenes, which are structurally related to hydrocarbons, or xanthophylls which are hydroxy, epoxy and oxy derivatives and are frequently esterified. The carotenoids most important in Imparting color to fruits and vegetables are derivatives of a- and -carotenes and lycopene. Carotenoids vary in their stability but, due to their unsaturated nature, they are generally susceptible to oxidation. Carotenes are important to... 

Carotenoids represent one of the broadest groups of natural antioxidants (over 600 characterized structurally) with significant biological effects and numerous industrial applications. Lycopene is a typical acyclic carotene that serves as a starting metabolite for formation of carotenoid derivatives via specific routes (p-carotene, torulene, etc.). Xanthophylls include hydroxy-, methoxy- oxo-, epoxy-, carboxy-, and aldehydic groups (torularhodin, zeaxanthin, astaxanthin, etc.), which results in a broad structural variety of carotenoid compounds. 

Lycoxanthin ( )/, if-caroten-16-ol), also in ripe berries of S. dulcamara L. Lycopene 1,2-epoxide [(25)-l,2-epoxy-l,2-dihydro- /, /-carotene]... 

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