11-cis-Retinol

This reaction was also used in a synthesis of 13-cis-retinoic acid.2 Thus reduction of 3 under the same conditions gives the triethylsilyl ether (4) of 13-cis-retinol, with retention of the geometry of the terminal double bond. This product can be converted to 13-cis-retinoic acid by deprotection and oxidation (60% yield). 

Determination of vitamin A by HPLC Part 1 Measurement of all-trans and 13 cis retinol... 

Reversed-phase chromatography using semiaqueous mobile phases can separate all-trans-retinol from 13-cis-retinol, albeit rather poorly. Further separation of the minor cis isomers is not... 

The two cellular retinol binding proteins bind aU-trans- and 13-cis-retinol, but not 9-cis- or 11-ds-retinol, or retinoic acid. They also bind retinaldehyde, although there is a distinct retinaldehyde binding protein in the eye ... 

Cis-retinol has 75% of the biological activity of all-tra/rs-retinol, and reti-naldehyde has 90%. Food composition tables give total preformed vitamin A as the sum of all-trans-retinol + 0.75 x 13-cis-retinol -I- 0.9 x retinaldehyde (Holland et al., 1991). 

In the case of CRBP and CRBPII, a number of retinoids have been tested (MacDonald and Ong, 1987 Cheng et al., 1991). No binding to CRBP or CRBPII occurred with 9-c - or 11-cis-retinol. However, binding was detected with 13-cis-retinol and 3-dehydroretinol. One unusual finding was that CRBPII but not CRBP had a detectable affinity for all-tram-retinaldehyde. Later studies (Li et al., 1991) showed that CRBP could bind retinol or retinal but that it had a 100-fold higher affinity for the alcohol. 

There are many retinol containing preparations to treat vitamin deficiency states. Retinoids are also used to treat dermatological diseases like acne, psoriasis, Darier s disease, and ichthyosis. Tretinoin, all-trans-retinoic acid, is a topical preparation while isotretinoin or 13-cis-retinoic acid, and etretinate are available for oral administration. 

Much recent interest has been aroused by the fact that retinoid compounds, including both retinol and retinoic acid, reduce the incidence of experimentally induced cancer. In addition, 13-czs-retinoic acid taken orally is remarkably effective in treatment of severe cystic acne. s However, both vitamin A and retinoic acid in large doses are teratogenic, i.e., they cause fetal abnormalities. The use of 13-cis-retinoic acid during early phases of pregnancy led to a high incidence of major malformations in infants born.1 11 1... 

The parent vitamin A compound, retinol, has the empirical formula C2oH3oO and a molecular weight (MW) of 286.44. The molecule comprises a cyclohexenyl (/3-ionone) ring attached at the carbon-6 (C-6) position to a polyene side chain whose four double bonds give rise to cis-trans (geometric) isomerism. The predominant isomer, all-trans-retinol (Fig. 1), possesses maximal (100%) vitamin A activity and is frequently accompanied in natural foodstuffs by smaller amounts of 13-ds-retinol, which exhibits 75% relative activity in the rat (6). Other cis isomers of retinol also occur in nature, but they are of low potency, and their contribution to the total vita-... 

Table V. Effect of retinol, 13-cis-retinoic acid and 3-carotene on 2-FA-induced mutagenesis in J5. typhimurium (TA98) mediated...

Modulation of Mutagenicity by the Intestinal Carcinogen 3,21-Dimethyl-4-Aminobiphenyl. We wished to examine the effect of retinol, 3-carotene and 13-cis-retinoic acid on yet another aromatic amine,... 

Table VIII. Effect of 13-cis-retinoic acid, 3-carotene and retinol on...

Electronic Absorption Spectroscopy. The absorption spectra of some polyenes in the crystalline state have been studied. On adsorption of certain gases on the crystallite surfaces, a new band appears on the low-energy side of the long-wavelength band in the spectra of these polyenes, e.g. at 536, 537, and 375 nm for all- trans-ft-carotene, 15-cis-/3-carotene, and retinyl compounds, respectively.92 The surface pressure vs. area isotherms and absorption spectra of all-trans-, 9-cis-, and 13-cis-retinal, all-trans-retinol, and all- trans-retinyl acetate have been studied at air-water and air-solid interfaces, respectively. The spectra of monolayers of the isomeric retinals showed a red shift of 15 lnm compared with the solution spectra, whereas... 

Gamble MV, Mata NL, Tsin AT, Mertz IR, and Blaner WS (2000) Substrate specificities and 13-cis-retinoic acid inhibition of human, mouse and bovine ds-retinol dehydrogenases. Biochimica et Biophysica Acta 1476,3-8. 

Physical Methods.—Separation and Assay. A range of isomers of astaxanthin (8) diacetate (9-cis, 13-cis, 15-cis, 9,9 -di-cis, 9,13-di-cw, 9,13 -di-cw, 13,13 -di-cw, 13,15-di-cw), prepared by thermal and iodine-catalysed isomerization of irans-(S) have been separated by h.p.l.c.126 A procedure has been developed for separation of bean leaf etioplast pigments, including carotenoids,127 by h.p.l.c. H.p.l.c. separations of esters of all-trans-, 9-cis-, 11-cw-, and 13-cw-retinol,128-130 and determinations of retinol in serum,131 retinol and 13-cw-retinoic acid,132 and the aromatic retinoid (195)133 in plasma have been described. A reversed-phase ion-pair... 

Whereas retinol and its esters (which are the forms of vitamin A in foods) are toxic at higher intake or supplement levels, synthetic analogs may avoid this toxicity, examples being derivatives of retinoic acid. A componnd known as 13-cis-retinoic acid has been noted to reverse premahgnant lesions in the case of certain kinds of... 

Takeda, N. Yamamoto, A, Simultaneous determination of 13-cis- and all-trans-retinoic acids and retinol in human serum by high-performance liquid chromatography. J.Chromatogr.B, 1994, 667, 53—59... 

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