title: Plasma appearance of unesterified astaxanthin geometrical E/Z and optical R/S isomers in men given single doses of a mixture of optical 3 and 3'R/S isomers of astaxanthin fatty acyl diesters.
abstract: Appearance, pharmacokinetics and distribution of astaxanthin all-E-, 9Z- and 13Z-geometrical and (3R,3'R)-, (3R,3'S)- and (3S,3'S)-optical isomers in plasma fractions were studied in three middle-aged male volunteers (41-50 years) after ingestion of a single meal containing first a 10-mg dose equivalent of astaxanthin from astaxanthin diesters, followed by a dose of 100 mg astaxanthin equivalents after 4 weeks. Direct resolution of geometrical isomers and optical isomers of astaxanthin dicamphanates by HPLC after saponification showed that the astaxanthin consisted of 95.2% all-E-, 1.2% 9Z- and 3.6% 13Z-astaxanthin, of (3R,3'R)-, (3R,3'S; meso)- and (3S,3'S)-astaxanthin in a 31:49:20 ratio. The plasma astaxanthin concentration-time curves were measured during 76 h. Astaxanthin esters were not detected in plasma. Maximum levels of astaxanthin (C(max)=0.28+/-0.1 mg/l) were reached 11.5 h after administration and the plasma astaxanthin elimination half-life was 52+/-40 h. The C(max) at the low dose was 0.08 mg/l and showed that, the dose response was non-linear. The (3R,3'R)-astaxanthin optical isomer accumulated selectively in plasma compared to the (3R,3'S)- and (3S,3'S)-isomers, and comprised 54% of total astaxanthin in the blood and only 31% of total astaxanthin in the administered dose. The astaxanthin Z-isomers were absorbed selectively into plasma and comprised approximately 32% of total astaxanthin 6-7.5 h postprandially. The proportion of all-E-astaxanthin was significantly higher in the very low density lipoproteins and chylomicrons (VLDL/CM) plasma lipoprotein fraction than in the high density lipoproteins (HDL) and low denisty lipoproteins (LDL) fractions (P<0.05). The results indicate that a selective process increase the relative proportion of astaxanthin Z-isomers compared to the all-E-astaxanthin before uptake in blood and that the astaxanthin esters are hydrolyzed selectively during absorption.
authors.affiliation: AKVAFORSK, Institute of Aquaculture Research AS, N-6600 Sunndalsøra, Norway.
authors.forename: Gladis N
authors.initials: GN
authors.lastname: Coral-Hinostroza
authors.forename: Trine
authors.initials: T
authors.lastname: Ytrestøyl
authors.forename: Bente
authors.initials: B
authors.lastname: Ruyter
authors.forename: Bjørn
authors.initials: B
authors.lastname: Bjerkeng
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002338:Carotenoids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004952:Esters / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D007536:Isomerism; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure; D013997:Time Factors; D024341:Xanthophylls; D019207:beta Carotene / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D004952:Esters; D005227:Fatty Acids; D024341:Xanthophylls; D019207:beta Carotene; D002338:Carotenoids; C005948:astaxanthine