Oxidation of zeaxanthin. Isolation and properties of 3-hydroxyretinene

Abstract

1. Anthers of Delonix regia flowers are a rich source of zeaxanthin. 2. Oxidation of zeaxanthin with hydrogen peroxide in the presence of osmium tetroxide results in the formation of 3-hydroxyretinene as one of the products. 3. 3-Hydroxyretinene gives 3-acetoxyretinene with acetic anhydride, and an oxime with hydroxylamine hydrochloride. 4. Reduction of 3-hydroxyretinene with sodium borohydride yields 3-hydroxyvitamin A. 5. Treatment of 3-hydroxyvitamin A with dry ethanolic hydrogen chloride results in the formation of 3-ethoxyanhydrovitamin A (anhydrovitamin A(2)) and a compound that resembles naturally occurring anhydrovitamin A(2).

Conversion of lutein into dehydroretinol by the freshwater fish,Saccobranchus fossilis

“…Crystalline synthetic p-carotene (Fluka AG, Buchs SG, Switzerland) and retinyl acetate (Roche Products Ltd, Bombay) were used. Zeaxanthin was isolated from the anthers of Delonix rezia (locally grown) by the method previously described (Barua & Barua, 1966). It was purified by repeated chromatography on deactivated alumina and crystallized from methanol (m.p.…”

Occurrence of 3-hydroxyretinol in the freshwater fish Bagarius bagarius and Wallago attu. Isolation and synthesis

“…3-Hydroxyretinal obtained thus, and 3-hydroxyretinal obtained synthetically by the ox1-Vol. 168 dation of zeaxanthin (fi,6f-carotene-3,3'-diol) by the method of Barua & Barua (1966), were co-chromatographed as follows: two spots, one of the 3-hydroxyretinal obtained by the oxidation of 3-hydroxyretinol and another of 3-hydroxyretinal obtained by the oxidation of zeaxanthin, and a third spot containing a mixture of the two, were applied to a silicagel plate (0.25mm thick) and subjected to t.l.c. The solvent system used was acetone/light petroleum (3:7, v/v).…”

“…(i) Preparation of 3hydroxyretinal. The procedure described by Barua & Barua (1966) was used. Zeaxanthin (100mg) was dissolved in diethyl ether (250ml), and 15 g of anhydrous Na2SO4 and 2ml of 2% (w/v) OS04 solution were added with stirring.…”

“…After about 15min, 30ml of 30 % (v/v) H202 solution was added until the solution became yellow. 3-Hydroxyretinal was isolated and purified by chromatography as described by Barua & Barua (1966).…”

“…(ii) Preparation of 3-hydroxyretinol. 3-Hydroxyretinal (10mg) was reduced with NaBH4 as described by Barua & Barua (1966) and purified by chromatography on an alumina column. The purified product (6.8mg) showed Aax.…”