Diapo-carotenoids

Annatto is classified as El 60(b). It is extracted from the seeds of the tree Bixa orellana which grows in America, India and East Africa. The extract is a mixture of two pigments, bixin and nor-bixin. Bixin is oil soluble, whereas nor-bixin is water soluble (it is one of the two water soluble carotenes - the other is crocin), and both of the pigments are diapo-carotenoids. Annatto has long been used as a food colouring and also has some uses as a food flavouring. 

The diapo-carotenoid crocetindial (25) and the corresponding oxoacid were isolated from Jacquinia augustifolia. ... 

The coloring principles are carotenoids, mostly bixin (oil-soluble) and norbixin (water-soluble), with bixin (especially the cis isomer) in major concentration (2.5% dry wt.). Norbixin is the principle component of the water-soluble dyes of annatto and is formed by the removal of the methyl esters of bixin. Both a- and P-forms of norbixin are found in water-soluble annatto dye. (—)-Bixin (syn. a-bixin) is unstable and during extraction is usually converted to trans-hixin (syn. P-bixin), the stable isomer, which is also known as isobixin. Bixin is a monomethyl ester of norbixin (a dicarboxylic acid) it is readily hydrolyzed by alkalis during alkali extraction of annatto to the dicarboxylic acid, norbixin (evans MERCK).Annatto also contains P-carotene (6.8-11.3 mg/lOOg), apocarotenoids, diapo-carotenoids, an essential oil (with the sesquiterpene ishwarane as the major component), pentosans, pectin, protein (13-17%), tannins, and others (evans). 

The intermediate 8,8 -diapo-20-acetoxycarotene-8,8 -dial (81) has been used to synthesize the cross-conjugated carotenoid aldehydes , y-caroten-20-al (82), (2/ ,2 J )-2,2 -bis-(3-methylbutyl)-3,4,3, 4 -tetrahydro-t/>, /f-caroten-20-al (83),... 

Eleven apo-carotenoids (1-11), including five new compounds, 4, 6, 9,10 and 11, were isolated from the fruits of the red paprika collected from Japan by Maoka et al. (2001b). The structures of new apocarotenoids were determined to be apo-14 -zeaxanthinal (4), apo-13-zeaxanthinone (6), apo-12 -capsorubinal (9), apo-8 -capsorubinal (10) and 9,9 -diapo-10,9 -retro-carotene-9,9 -dione (11) by spectroscopic analysis. The other six known apocarotenoids were identified to be apo-8 -zeaxanthinal (1), apo-lO -zeaxanthinal (2), apo-12 -zeaxan-thinal (3), apo-15-zeaxanthinal (5), apo-11-zeaxanthinal (7) and apo-9-zeaxanthinone (8), which had not been found previously in paprika. These apocarotenoids were assumed to be oxidative cleavage products of C40 carotenoid, such as capsanthin in paprika. 

Triterpenoid Carotenoids. Two novel triterpenoid xanthophylls from Streptococcus faecium have been identified " as 4,4 -diapo-7, 8 -dihydro-i/, / -caroten-4-al (16) and 4,4 -diapo-i/, A-caroten-4-al (17). Two other C30 carotenoids, jS-citraurinene 8 -apo-/S-caroten-3-ol (18)] and /8-citrauroP [8 -apo-/3-carotene-3,8 -diol (19)], both isolated from citrus fruits, are likely to be derived from C40 carotenoids. Spectroscopic data were presented for both compounds. 

The Heliobacteriaceae only have Cj acyclic carotenes, 4,4"-diapocarotenes, instead of the usual carotenoids (Fig. 11 Takaichi et al., 1997b). 4,4"-Diaponeurosporene is the major carotene, and diapophytoene, diapophytofluene, diapo-C-carotene and diapolycopene are also found as minor components. Two genes encoding enzymes in the early steps of diapocarotene biosynthesis have been... 

Fig. 11. The predicted pathway for the biosynthesis of diapo-carotene in the He) iobacteriaceae with that of C4g-type carotenoids, and the esterified alcohol of BChls. CrtE, CrtB and Crtl are found in Rhodobacier (Armstrongsla]., 1989 Langetal., 1995), CrtM and CrtN in Staphylococcus (Wieland et al., 1994), and CrtM in Hba. mobilis (Xiong et al., 1998).

Brain. 6, -Diapo-4f>4/mCGrotenedioic acid mono-nwrifyf tstti1. CwHw04 mol wi 394.49. C 76.11%, H 7.66%, 0 16.22%. Carotenoid carboxylic acid isolated from seeds of Biro pre/tartc L., Bixaceae Kuhn, Ehmann, Helv. Chim. 

The 1-methoxy-2-oxo-3.4-didehydro-1,2-dihydro-vi end group occurs in such carotenoids as spheroidenone and 2,2 -diketospirilloxanthin (199), which possesses a conjugated system of 15 double bonds. 2,2 -Diketospirilloxanthin (199) was synthesized via a C5 + (Cio + Cio + Cio) + C5 = C4o strategy [95]. The central Cao-building block 200 was obtained by a Wittig reaction between two moles of phosphonium salt 201 [96,97] and 15,15 -didehydro-12,12 -diapo-carotene-12,12 -dial (48). Aldol condensation of 200 with two moles of 3-methoxy-3-methylbutan-2-one (202) and NaOH, and then partial hydrogenation in the presence of Lindlar catalyst led to 2,2 -diketospirilloxanthin (199) in an overall yield of 38% referred to 202 Scheme 45). 

Carotenoids act as antioxidants in solution, micelles, and liposomes (Hill et al. 1995, Mortensen and Skibsted 1997, Mortensen et al. 1997, Woodall et al. 1997). The scavenging ability of the carotenoids P-carotene, 8 -apo-P-caroten-8 -al, can-thaxanthin, 7 -apo-7 ,7 -dicyano-p-carotene, ethyl 8 -apo-P-caroten-8 -oate, and 7,7 -diapo-7,7 -di-phenylcarotene towards radical HOO correlated with their redox properties (Polyakov et al. 2001). 

S Takaichi, K Inoue, M Akaike, M Kobayashi, H Oh-oka, MT Madigan. The major carotenoid in aU known species of hehobacteiia is the C30 carotenoid 4,4 -diapo-neurosporene, not neurosporene. Arch Microbiol 168 277-281, 1997. 

Bixin, 6 -methyl hydrogen 9 -cis-6,6 -diapocarotene-6,6 -dioate (lUPAC, 1974 also 6,6 -diapo-4/,4/-carotenedioitic acid monomethyl ester and carotenoid-carboxylic acid), is isolated from seedsof5wa orellana L. MerckIndex, 1996 Schweppe, 1992). Classed here as a carotenoid compound, it also has the Colour Index designation Cl 75120. 

Crocetin, 8,8 -diapo-4r,4r-carotenedioic acid (carotenoid-dicarboxylic acid) is the main dyestuff produced by stamens of the saffron plant. Crocus sativus L. and by the seeds of Gardenia jasminoides Ellis (Schweppe, 1992 Merck Index, 1996). It has the Colour Index (1971) designation Cl 75100. 

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