Isolation of an Unusually Stable Cis‐Isomer of Alloxanthin from a Bleached Autolysed Culture of Chroomonas salina Grown Photoheterotrophically on Glycerol. Observations on Cis‐Trans Isomerization of Alloxanthin

Abstract

SYNOPSIS. A new carotenoid, manixanthin, was isolated from a bleached, autolysed culture of the marine cryptomonad Chroomonas salina grown on glycerol in light, after the culture showed disappearance of the chlorophylls and carotenoids normally produced. Manixanthin lacked carbonyl, ester, and epoxy groups in chemical tests, whilst its spectroscopic properties indicated a conjugated nonaene chromophore. In its chromatographic mobility, manixanthin closely resembled alloxanthin, the major normal xanthophyll of the cryptomonad. The iodine‐catalysed photostereomutation of manixanthin produced the same equilibrium mixture of cis‐isomers as that given by similar treatment of alloxanthin. This mixture of isomers completely lacked the all‐trans alloxanthin and contained ∼60% manixanthin. It was concluded that manixanthin is an unusually stable cis‐isomer of alloxanthin, and is presumably produced in the culture medium by the action of light on alloxanthin released by autolysed cells of the cryptomonad. The unusual stability of manixanthin relative to alloxanthin was investigated by effecting partial stereoisomerizations under conditions using either of heat, light, or iodine, and evidence was obtained for a series of at least 10 isomers with a trend of stability increase from alloxanthin to manixanthin. It was inferred that manixanthin may be 9,9′‐dicis‐alloxanthin.

Suppressive Effects of Alloxanthin and Diatoxanthin from Halocynthia roretzi on LPS-induced Expression of Pro-inflammatory Genes in RAW264.7 Cells

“…Both carotenoids can be found in several algae such as the Cryptophyceae 27) and dinoflagellates 28) . 9-cis Alloxanthin has also been isolated from a bleached, autolyzed culture of the marine cryptomonad Chroomonas salina grown on glycerol in light 29) . Thus, although distribution of these carotenoids is widely known, to the best of our knowledge, there are no reports about the potential health benefits of alloxanthin and diatoxanthin.…”

The keto-carotenoids of two marine coccoid members of the Eustigmatophyceae

“…The rest of the extract was fractionated by repeated thin-layer chromatography (TLC) in various adsorbent-solvent systems, and the isolated carotenoids were characterized from absorption spectra as well as acid treatment for epoxy groups or NaBH4 treatment for keto groups. For experimental details, see Cheng et al (1974) and Antia & Cheng (1977). No attempt was made to quantify the pigments in terms of algal weight, and the carotenoid proportions were roughly assessed by comparing optical densities at their principal Amax, assuming equal specificextinction coefficients.…”

Physiological studies of phototrophy and heterotrophy in two algae with contrasting nutritional characteristics, Pyrenomonas salina (Cryptophyceae) and Poterioochromonas malhamensis (Chrysophyceae)

“…Facultative heterotrophy in P. salina had been examined in Antia's laboratory (Antia et al, 1 1974Cheng et al, 1974;, with a focus on the effect of glycerol assimilation on the alga's growth, starch production, and lipid production.…”