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At least 19 recordsLinked to original sources

PubMed1992

Isolation of astaxanthin over-producing mutants of Phaffia rhodozyma and their fermentation kinetics.

Phaffia rodozyma CCRC-21346, CBS-6938, and CBS-5908 were treated with mutagenic agent NTG (N-methyl-N'-nitro-N-nitrosoguanidine) several times, then they were plated onto yeast-malt agar containing beta-ionone as a selective medium. Several isolates had increased astaxanthin content compared with the parental natural isolates. NCHU-FS301, one of the NTG treated strains, produced considerably more astaxanthin (1515.63 micrograms/g yeast) than the parent CBS-6938 (565.08 micrograms/g yeast). In studying the effects of carbon sources on the red pigment formation, it was found that glucose supported the highest total astaxanthin production (7809.3 micrograms/l). Yeast extract was the best nitrogen source in supporting the highest total astaxanthin formation (8637.5 micrograms/l). Beef extract, yeast extract, and potassium nitrate added in an equal ratio as a nitrogen source supported more pigment formation (8052.6 micrograms/l) than the rest of the mixture tested. Using kinetic parameters of specific growth rate (mu) and specific astaxanthin productivity (qp) to judge the association between growth behavior and product formation, the NCHU-FS301 showed more positive growth-associated fermentation type than the parent strain. These astaxanthin-overproducing mutants could be useful for the aquacultural industry in providing a natural source of astaxanthin.

Carbon↗

PubMed1991

Photobleaching of astaxanthin and canthaxanthin. Quantum-yields dependence of solvent, temperature, and wavelength of irradiation in relation to packaging and storage of carotenoid pigmented salmonoids.

The quantum yield for the photobleaching of astaxanthin (the carotenoid of wild salmonoids) and of canthaxanthin (the closely related carotenoid used as a feeding additive for farmed salmonoids) has been determined for monochromatic light at different wavelengths and in different solvents. Astaxanthin is less sensitive to light than canthaxanthin. The photobleaching is strongly wavelength dependent, and the quantum yield for astaxanthin dissolved in chloroform at 22 degrees C is 3.2 x 10(-1) mol.Einstein-1 at 254 nm, 3.1 x 10(-2) at 313 nm, and 1.6 x 10(-6) at 436 nm, respectively. The quantum yields are less dependent on the nature of the solvent and show no simple correlation with oxygen solubility, i.e. for 366 nm excitation of astaxanthin the quantum yields are 6.1 x 10(-5) mol.Einstein-1 in acetone, 1.2 x 10(-4) in saturated vegetable oil, 1.9 x 10(-4) in chloroform, and 3.4 x 10(-4) solubilized in water, respectively. The photobleaching quantum yield provides an objective measure of the light sensitivity of the carotenoids in relation to the discolouration of carotenoid-pigmented salmonoids. The quantum yield was also found to be independent of the carotenoid concentration and, in a homogenous solution, of light intensities. For astaxanthin solubilized in water, the quantum yield increases for low light intensities. Excitation of astaxanthin solubilized in water using visible light shows that the photobleaching quantum yield is independent of temperature, while excitation at 313 nm shows an increase in the quantum yield with increasing temperatures, corresponding to an energy of activation of 28 kJ.mol-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Inhibition of oxidative injury of biological membranes by astaxanthin.

The value of astaxanthin, a carotenoid pigment, in the treatment of oxidative injury is assessed. Astaxanthin protects the mitochondria of vitamin E-deficient rats from damage by Fe2(+)-catalyzed lipid peroxidation both in vivo and in vitro. The inhibitory effect of astaxanthin on mitochondrial lipid peroxidation is stronger than that of alpha-tocopherol. Thin layer chromatographic analysis shows that the change in phospholipid components of erythrocytes from vitamin E-deficient rats induced by Fe2+ and Fe3(+)-xanthine/xanthine oxidase system was significantly suppressed by astaxanthin. Carrageenan-induced inflammation of the paw is also significantly inhibited by administration of astaxanthin. These data indicate that astaxanthin functions as a potent antioxidant both in vivo and in vitro.

Animals↗

PubMed1991

Studies on the carotenoids in the muscle of salmon--V. Combination of astaxanthin and canthaxanthin with bovine serum albumin and egg albumin.

1. Bovine serum albumin (BSA) and/or egg albumin were bound to astaxanthin or canthaxanthin easily and the spectroscopic characteristics of these complexes were similar to those of astaxanthin or canthaxanthin in the salmon muscle. 2. This result indicates that astaxanthin-BSA, -egg albumin, canthaxanthin-BSA and -egg albumin complexes were basically similar to astaxanthin-actomyosin and/or canthaxanthin-actomyosin complex in the salmon muscle. 3. The binding of salmon actomyosin to astaxanthin or canthaxanthin is not specific.

Actomyosin↗

PubMed1991

Studies of immunomodulating actions of carotenoids. I. Effects of beta-carotene and astaxanthin on murine lymphocyte functions and cell surface marker expression in in vitro culture system.

The immunomodulating effects of carotenoids (beta-carotene and astaxanthin) on mouse lymphocytes were studied in in vitro culture system by use of assay for mitogen responses of spleen cells, thymocyte proliferation, interleukin 2 production, and antibody (Ab) production in vitro in response to sheep red blood cells. Changes of cell surface markers on spleen lymphocytes including Ia antigen (Ag), surface immunoglobulin, B220, and Thy-1 Ag were also examined. At a concentration of 10(-8) M, carotenoids did not show any significant effect on mitogen responses (phytohemagglutinin P and concanavalin A) on murine spleen cells, irrespective of the concentrations of mitogens used. Interleukin 2 production by murine spleen cells was not significantly altered by carotenoids in the culture media (10(-7) to 10(-9) M). [3H]thymidine incorporation by B6 thymocytes was somewhat enhanced in the presence of astaxanthin or beta-carotene when cultured in the concentration of 10(6)/ml. At higher concentrations of cells (5 x 10(6)/ml), such an effect was not observed. In assays of in vitro Ab production in response to sheep red blood cells, B6 spleen cells produced significantly more Ab-forming cells (plaque-forming cells, immunoglobulins M and G) in the presence of astaxanthin (greater than 10(-8) M) but not beta-carotene. Expression of Ia Ag seemed to be moderately enhanced on both Thy-1+ and Thy-1- spleen cells in the presence of astaxanthin (greater than 10(-9) M) but not beta-carotene. The expression of Thy-1 and surface immunoglobulin seemed unchanged with the treatment of these carotenoids. These results indicate that immunomodulating actions of carotenoids are not necessarily related to provitamin A activity, because astaxanthin, which does not have provitamin A activity, showed more significant effects in these bioassays and also indicate that such actions of carotenoid demonstrated in this study may be difficult to explain only by its oxygen-quenching capacity.

Adjuvants, Immunologic↗

PubMed1991

The lobster carapace carotenoprotein, alpha-crustacyanin. A possible role for tryptophan in the bathochromic spectral shift of protein-bound astaxanthin.

Crustacyanin, cross-linked with dimethyl pimelimidate to stabilize the protein against denaturation, was used to test the effects of tryptophan modification with BNPS-skatole [3-bromo-3-methyl-2-(nitrophenylmercaptol)-3H-indole] on the ability of the apoprotein to recombine with astaxanthin. The cross-linked apoprotein re-forms alpha-crustacyanin with astaxanthin in reasonable yield following incubation of the protein under the conditions for tryptophan modification in the absence of BNPS-skatole. The BNPS-skatole-treated protein reconstitutes with astaxanthin to give a carotenoprotein with lambda max. at 472 nm, that of the carotenoid in hexane, in a yield similar to that of the BNPS-skatole-untreated control. The implied involvement of tryptophan residues at the sites of astaxanthin attachment in crustacyanin and their possible roles in the binding sites of vitamin A in vitamin A-proteins are discussed in relation to the bathochromic spectral shifts of the chromophores.

Animals↗

PubMed1978

Simple method for the isolation of astaxanthin from the basidiomycetous yeast Phaffia rhodozyma.

A method is described for the quantitative and, possibly, large-scale extraction of astaxanthin from the yeast Phaffia rhodozyma. The method utilizes extracellular enzymes produced by the bacterium Bacillus circulans WL-12, which partially digests the yeast cell wall and renders the carotenoid pigments extractable by acetone or ethanol. Complete recovery of astaxanthin from heat-killed P. rhodozyma cells was obtained after growing B. circulans WL-12 on these yeast cells for 26 h and then extracting the yeast-bacterium mixture with acetone. A bacteria-free lytic system, which gave quantitative extraction of astaxanthin from P. rhodozyma, was obtained by concentrating the culture broth from the growth of B. circulans WL-12 on P. rhodozyma cells. Hydrolytic enzyme activities detected in this concentrate included beta-(1 leads to 3)-glucanase, beta-(1 leads to 6)-glucanase, alpha-(1 leads to 3)-glucanase, xylanase, and chitinase. The lytic system was found to work most efficiently at pH 6.5 and with low concentrations of yeast.

Bacillus↗

PubMed1992

[Hypercholesterolemic effect of canthaxanthin and astaxanthin in rats].

Three groups of male Wistar rats (130-140 g) were fed 30 days with a synthetic diets containing 0.1% of beta-carotene, canthaxanthin and astaxanthin respectively. Another group was fed with a synthetic diet without carotenoids. The results shows that the beta-carotene does not induce change in plasma cholesterol (49, 7 +/- 3.6 mg/dl), but canthaxanthin and astaxanthin induce a significant increase in cholesterol concentration (92.1 +/- 3.6 and 66.5 +/- 5.1 mg/dl). This increase is noted mainly in the HDL fraction of the lipoproteins. Canthaxanthin has more affinity than astaxanthin for the liver, principal site of lipoproteins catabolism. The hypercholesterolemic effect of these xanthophylls is not related to reported mechanisms of carotenoids in mammalian, because beta-carotene does not induce changes in plasma cholesterol.

Animals↗

PubMed1987

Resonance Raman study of reconstituted carotenoproteins incorporating astaxanthin and 15,15'-didehydroastaxanthin.

Two reconstituted carotenoproteins have been studied by resonance Raman spectroscopy. They were prepared from the apoprotein of the Asterias rubens carotenoprotein, asteriarubin and either astaxanthin or 15,15'-didehydroastaxanthin. Spectral properties of dehydrocarotenoids are first discussed. The spectral properties of the complexes are compared to those of the free carotenoids and of other carotenoproteins containing astaxanthin, and possible protein-carotenoid interactions are discussed. Greater delocalisation of the pi-electron system in the central part of the polyene chain, and the role of lateral methyl groups in binding is emphasised.

Animals↗

PubMed2026

Autophagy activation in granulosa cells as a mechanism of astaxanthin action: evidence from a pilot randomised trial in PMOS-associated infertility.

Astaxanthin (AST) has been reported to influence oxidative stress, endoplasmic reticulum stress, and apoptosis in women with polyendocrine metabolic ovarian syndrome (PMOS), formerly referred to as polycystic ovary syndrome (PCOS), but its effects on granulosa-cell (GC) autophagy remain unclear. Given the central role of autophagy in follicular development, this triple-blind, placebo-controlled pilot randomised trial evaluated whether AST modulates autophagy-related signalling in GCs and how these molecular effects relate to ovarian response. Fifty women with PMOS-related anovulatory infertility were enrolled between November 2023 and September 2024 and received AST (12 mg/day) or placebo for six weeks prior to oocyte retrieval; forty-four completed the study (21 AST, 23 placebo). Primary exploratory endpoints were molecular markers of adenosine monophosphate-activated protein kinase (AMPK)-autophagy signalling, and primary clinical outcomes included ovarian response indicators and cleavage stage embryo quality. AST supplementation increased autophagy-related gene 7 (ATG7) expression, enhanced autophagy flux, reduced apoptosis, and showed a trend toward increased AMPK activation. Before adjustment, AST improved oocyte maturity rate (OMR) and increased mature (metaphase II; MII) oocyte yield. After adjusting for age, body mass index, and anti-mullerian hormone level, total oocyte and MII oocyte yields remained significantly higher with AST, while OMR became non-significant. Among embryology outcomes, both the top-ranking embryo rate and the number of embryos suitable for cryopreservation were significantly higher with AST after adjustment. Pregnancy outcomes were numerically higher but not statistically significant. This pilot trial suggests that AST activates autophagy- and apoptosis-related pathways in GCs and may enhance oocyte competence and embryo quality in PMOS. Larger studies are needed to confirm these mechanistic and clinical effects.

Female↗

PubMed1992

Astaxanthin and canthaxanthin are potent antioxidants in a membrane model.

When the conjugated keto-carotenoids, either astaxanthin or canthaxanthin, are added to rat liver microsomes undergoing radical-initiated lipid peroxidation under air, they are as effective as alpha-tocopherol in inhibiting this process. This contrasts with the effect of beta-carotene, which is a much less potent antioxidant when added in this system, without the addition of other antioxidants.

Adjuvants, Immunologic↗

PubMed1992

Comparative accumulations of labelled carotenoids (14C-astaxanthin, 3H-canthaxanthin and 3H-zeaxanthin) and their metabolic conversions in mature female rainbow trout (Oncorhynchus mykiss).

1. One force-fed meal containing labelled 14C-astaxanthin (14C-Ax) and 3H-canthaxanthin (3H-Cx) or 3H-zeaxanthin (3H-Zx) was given to eight mature female rainbow trout. Ninety-six hours after the test meal ingestion, trout were killed and liver, skin, muscle and ovaries were dissected out. 2. Ax accumulated slightly more in muscle than Cx but in all tissues Ax and Cx were very significantly more concentrated than Zx. 3. 3H-Zx metabolites were found only in the liver, whereas 14C-phoenicoxanthin was the only metabolic pigment from 14C-Ax detected and was found in all investigated tissues. 4. 3H-Ax was found in the liver of all trout indicating that 3H-Cx and 3H-Zx were Ax precursors, and that salmonids probably possess carotenoid oxidative pathways unknown until now. 5. Labelled retinol1 and retinol2 were detected only in the liver and 3H-Zx was largely the predominant precursor of these two vitamin A forms.

Animals↗

PubMed1991

Complete sequence and model for the C1 subunit of the carotenoprotein, crustacyanin, and model for the dimer, beta-crustacyanin, formed from the C1 and A2 subunits with astaxanthin.

The complete sequence has been determined for the C1 subunit of crustacyanin, an astaxanthin-binding protein from the carapace of the lobster Homarus gammarus (L.). The polypeptide, 181 residues long, is similar (38% identity) to the other main subunit, A2 and to plasma retinol-binding protein. The tertiary structure of the C1 subunit has been modelled on that derived for the A2 subunit from the coordinates of retinol-binding protein. Residues lining the putative binding cavities and at the putative carotenoid binding sites of the two subunits are highly conserved. The carotenoid environments are characterized by a preponderance of aromatic and polar residues and the absence of charged side-chains. A tentative model for the dimer, beta-crustacyanin, formed between the two subunits with their associated carotenoid ligands, is discussed. The model is based on the crystal structure of the dimer of bilin-binding protein, a member of the same superfamily. This structure has enabled us to examine mechanisms for the bathochromic spectral shift of the protein-bound carotenoid and to identify likely contact regions between dimers in octameric alpha-crustacyanin.

Amino Acid Sequence↗

PubMed1989

[Variation in the composition of fatty acids of zeaxanthin and astaxanthin monoesters in the ovary and hepatopancreas of Penaeus schmitti during ovogenesis].

The carotenoid esters of the shrimp, Penaeus schmitti, were investigated by thin layer chromatography and absorption spectrophotometry. Astaxanthin monoester and zeaxanthin monoester were identified in hepatopancreas and ovaries during the sexual development. The nature of fatty acids derived from these natural esters has been determined quantitatively by gas chromatography of their methyl esters. The variations of linkage between fatty acids and carotenoids during ovogenesis are measured. The role of zeaxanthin monoester in carotenoids transfer from hepatopancreas to ovaries during this sexual development, and relations between lipid and carotenoid metabolism are discussed.

Animals↗

PubMed1976