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PubMed2000

Interaction of peroxynitrite with carotenoids in human low density lipoproteins.

Interaction of peroxynitrite, the product of the reaction between nitric oxide and superoxide, with carotenes (lycopene, alpha-carotene, and beta-carotene) and oxocarotenoids (beta-cryptoxanthin, zeaxanthin, and lutein) was studied both in homogeneous solution and in human low-density lipoproteins (LDL). All carotenoids prevented the formation of rhodamine 123 from dihydrorhodamine 123 caused by peroxynitrite, suggesting that the carotenoids react with peroxynitrite. Oxocarotenoids were as effective as biothiols, known scavengers of peroxynitrite, whereas lycopene, alpha-carotene, and beta-carotene exhibited a considerably more pronounced effect. Moreover, peroxynitrite caused a loss of carotenoids in LDL as was revealed by HPLC. The concentration of peroxynitrite causing half-maximal loss of carotenoids in LDL ranged from 13 +/- 3 to 68 +/- 3 microM for lycopene and lutein, respectively. Again, oxocarotenoids were less reactive in this system. A correlation between efficiency of carotenoids in the competitive assay with dihydrorhodamine 123 and the concentration of peroxynitrite causing half-maximal loss of carotenoids in LDL was observed (r(2) = 0.91). These findings suggest that carotenoids can efficiently react with peroxynitrite and perform the role of scavengers of peroxynitrite in vivo.

Arteriosclerosis↗
PubMed1995

Monitoring of ubiquinol-10, ubiquinone-10, carotenoids, and tocopherols in neonatal plasma microsamples using high-performance liquid chromatography with coulometric electrochemical detection.

A method for measuring the lipophilic antioxidants alpha-tocopherol, gamma-tocopherol, ubiquinol-10, ubiquinone-10, beta-cryptoxanthin, and beta-carotene in 5 or 10 microliters neonatal plasma is presented. First lipid extraction together with the internal standards gamma-tocotrienol, ubiquinone-7, ubiquinol-9, ubiquinone-9, and ethyl beta-apo-8'-carotenoate was carried out. Then the components were separated on a RPC2/C18 column. Coulometric electrochemical detection was performed using the reduction-oxidation mode (-0.60 V; -0.15 V; +0.60 V). Detection limits for all components were between 21 and 60 fmol, corresponding to 0.004 and 0.012 mumol/liter plasma; the within-day precision (coefficient of variation) was between 3 and 14% for all measured substances. Reference values are given for healthy newborn children from the second to the sixth day of life. Using the presented HPLC technique it is possible to monitor the concentrations of lipophilic antioxidants in plasma of sick immature newborn children in order to study effects of oxidative stress.

Antioxidants↗
PubMed1990

Carotenoids of human colostrum.

Colostrum, the initial postpartum secretion of the breast, ordinarily has a distinct yellow color due to carotenoids of its fat globules. This pigmentation progressively diminishes as milk production increases during the first week of lactation. Identity of these carotenoids was investigated by means of thin-layer chromatography, high performance liquid chromatography and spectral analysis. Alpha- and beta-carotene, lycopene and beta-cryptoxanthin were revealed as major chromogens. A component corresponding to lutein and/or zeaxanthin was also detected by both chromatographic techniques. Extracts of 23 saponified colostrum samples from 10 donors revealed considerable variation in total carotenoid concentration (0.34-7.57 micrograms/ml of colostrum). Multiparous mothers had greater mean colostrum carotenoid concentrations than did the primiparae, 2.18 +/- 1.94 vs 1.14 +/- 1.32 micrograms/ml, respectively. Seven of the eight primiparous donors' samples had little or no yellow color. These findings imply a difference in carotenoid transport by breasts that have lactated as compared to those that have not. The interrelation of carotenoids, lactation and breast cancer is discussed.

Carotenoids↗
PubMed2003

Synthetic and tomato-based lycopene have identical bioavailability in humans.

BACKGROUND: Bioavailability studies with lycopene have focused on natural sources. A synthetic source has recently become available. AIM OF THE STUDY: To determine the relative bioavailabilities of synthetic and tomato-based lycopene in free living volunteers in a single-blind, randomized, placebo-controlled, parallel trial. METHODS: Three groups (n=12/group) of healthy, normolipemic male and female subjects with a mean baseline serum lycopene concentration of 0.36 micro mol/L took a dose of 15 mg/day total lycopene for 28 days from either Lycovit 10% (beadlets, BASF, Germany) or Lyc-O-Mato (beads, LycoRed Natural Products, Israel) or a placebo (without lycopene) together with the main meal. The increase in serum lycopene from baseline was used as the parameter of bioavailability. RESULTS: Synthetic and tomato-lycopene resulted in significant increases above baseline of serum total lycopene by 0.58 and 0.57 micro mol/L, trans-lycopene by 0.34 and 0.41 micro mol/L, and total-cis-lycopene by 0.24 and 0.16 micro mol/L, whereas no significant changes were found in the placebo treatment. The mean serum total lycopene response to synthetic and natural lycopene was not significantly different. Neither lycopene source affected the other serum carotenoids, viz. alpha-carotene, beta-carotene, beta-cryptoxanthin, zeaxanthin and lutein. CONCLUSION: We conclude that synthetic and natural lycopene are equivalent sources of lycopene and that there is no interaction with other circulating carotenoids.

Adult↗
PubMed1993

Carotenoid content of fruits and vegetables: an evaluation of analytic data.

The test of the association between dietary intake of specific carotenoids and disease incidence requires the availability of accurate and current food composition data for individual carotenoids. To generate a carotenoid database, an artificial intelligence system was developed to evaluate data for carotenoid content of food in five general categories, namely, number of samples, analytic method, sample handling, sampling plan, and analytic quality control. Within these categories, criteria have been created to rate analytic data for beta-carotene, alpha-carotene, lutein, lycopene, and beta-cryptoxanthin in fruits and vegetables. These carotenoids are also found in human blood. Following the evaluation of data, acceptable values for each carotenoid in the foods were combined to generate a database of 120 foods. The database includes the food description; median, minimum, and maximum values for the specific carotenoids in each food; the number of acceptable values and their references; and a confidence code, which is an indicator of the reliability of a specific carotenoid value for a food. The carotenoid database can be used to estimate the intake of specific carotenoids in order to examine the association between dietary carotenoids and disease incidence.

Carotenoids↗
PubMed1990

Serum concentrations of carotenoids, retinol, and alpha-tocopherol in healthy persons determined by high-performance liquid chromatography.

Serum concentrations of alpha-carotene (AC), beta-carotene (BC), lycopene (LY), beta-cryptoxanthin (CR), zeaxanthin (including lutein. ZX), canthaxanthin (CX), retinol (RE), and alpha-tocopherol (TO) in healthy persons (618 males and 1,196 females) aged 7-86 years were determined by HPLC. Serum concentrations of BC among persons aged 20-49 years were higher with increasing age in females, but not in males. Serum CR concentrations decreased with age ranging from 7 to 39 years, while ZX concentrations rose in the age group of 20 to 59 years for both sexes. In contrast, serum RE concentrations and ratios of RE/BC and RE/CR, especially in males aged 20-49, were higher with age. Serum TO values in both sexes rose with age and were similar.

Adolescent↗
PubMed1994

Effects of micronutrients and antioxidants on lipid peroxidation in human plasma and in cell culture.

Plasma levels of triglycerides, retinol, cholesterol, lipid-phase antioxidants (alpha-, gamma-tocopherols, beta-carotene, alpha-carotene, lycopene, beta-cryptoxanthin and lutein/zeaxanthin), and thiobarbituric acid-reactive substances (TBA-RS), as an indicator of lipid peroxidation, were repeatedly determined in nine individuals over a 3-month period. Levels of TBA-RS were positively correlated with plasma triglycerides and gamma-tocopherol, and negatively correlated with plasma carotenoids. These results were consistent with in vitro cell culture studies which showed increased TBA-RS for cells supplemented with linolenic acid and decreased levels when treated with beta-carotene. We conclude that TBA-RS measurements in plasma accurately reflect the level of peroxidizable substrate as modified by the presence of a variety of dietary antioxidants, particularly carotenoids. Although the inter- and intra-individual variabilities for TBA-RS are comparable with the micronutrients and antioxidants measured in this study, high interassay variability and the strong association with the more commonly measured plasma triglycerides suggest the TBA-RS assay to be of limited use in epidemiologic studies. However, this assay does appear to be useful in cell culture studies where experimental conditions can be better controlled. Low ratios of inter- to intra-individual variability in some of the plasma micronutrient and lipid-phase antioxidants measured suggest that multiple samples may be required to characterize individuals in studies evaluating the relation between these plasma constituents and disease incidence.

Animals↗
PubMed2005

Incorporation of carotenoid esters into liposomes.

Carotenoid esters are investigated for their interaction with liposomal membranes and compared with their corresponding free (non-esterified) carotenoids. A monoester (beta-cryptoxanthin) and two diesters (zeaxanthin and lutein) were chosen. Egg yolk phosphatidylcholine liposomes served as the membrane model. We measured the sizes of the liposomes by photon correlation spectroscopy. The incorporation yields were determined spectrophotometrically. From liposomes simultaneously doped with the fluorescent dye Laurdan, fluidity changes of the liposomes were obtained. In summary, the results indicate that the carotenoid esters: (i) get incorporated, but at a lower yield than their corresponding free carotenoids, (ii) also increase the membrane rigidity as do the free carotenoids, and (iii) increase the liposome sizes significantly, but after extrusion through an 0.1 mum filter the sizes resemble with the exception of the liposomes incorporated with lutein diesters, they remain bigger indicating an elastic property due to two different accessible locations in the membrane.

Antioxidants↗
PubMed2006

The crtS gene of Xanthophyllomyces dendrorhous encodes a novel cytochrome-P450 hydroxylase involved in the conversion of beta-carotene into astaxanthin and other xanthophylls.

The conversion of beta-carotene into xanthophylls is a subject of great scientific and industrial interest. We cloned the crtS gene involved in astaxanthin biosynthesis from two astaxanthin producing strains of Xanthophyllomyces dendrorhous: VKPM Y2410, an astaxanthin overproducing strain, and the wild type ATCC 24203. In both cases, the ORF has a length of 3166 bp, including 17 introns, and codes for a protein of 62.6 kDa with similarity to cytochrome-P450 hydroxylases. crtS gene sequences from strains VKPM Y2410, ATCC 24203, ATCC 96594, and ATCC 96815 show several nucleotide changes, but none of them causes any amino acid substitution, except a G2268 insertion in the 13th exon of ATCC 96815 which causes a change in the reading frame. A G1470 --> A change in the 5' splicing region of intron 8 was also found in ATCC 96815. Both point mutations explain astaxanthin idiotrophy and beta-carotene accumulation in ATCC 96815. Mutants accumulating precursors of the astaxanthin biosynthetic pathway were selected from the parental strain VKPM Y2410 (red) showing different colors depending on the compound accumulated. Two of them were blocked in the biosynthesis of astaxanthin, M6 (orange; 1% astaxanthin, 71 times more beta-carotene) and M7 (orange; 1% astaxanthin, 58 times more beta-carotene, 135% canthaxanthin), whereas the rest produced lower levels of astaxanthin (5-66%) than the parental strain. When the crtS gene was expressed in M7, canthaxanthin accumulation disappeared and astaxanthin production was partially restored. Moreover, astaxanthin biosynthesis was restored when X. dendrorhous ATCC 96815 was transformed with the crtS gene. The crtS gene was heterologously expressed in Mucor circinelloides conferring to this fungus an improved capacity to synthesize beta-cryptoxanthin and zeaxanthin, two hydroxylated compounds from beta-carotene. These results show that the crtS gene is involved in the conversion of beta-carotene into xanthophylls, being potentially useful to engineer carotenoid pathways.

Amino Acid Substitution↗
PubMed1998

A routine method for the simultaneous measurement of retinol, alpha-tocopherol and five carotenoids in human plasma by reverse phase HPLC.

We describe a simple isocratic HPLC method for the accurate and precise measurement of retinol, alpha-tocopherol and the major carotenoids in plasma using UV detection. Reference ranges for retinol, alpha-tocopherol and five carotenoids are determined in a healthy population group. The most abundant carotenoids found in plasma were beta-carotene, lycopene, lutein and cryptoxanthin. Retinol, alpha-tocopherol and carotenoids were determined simultaneously using two internal standards, retinol acetate for retinol and tocopherol acetate for alpha-tocopherol and carotenoids. The use of echinenone as an internal standard for carotenoids was investigated. The protective effect of an antioxidant (ascorbic acid) on the stability of samples and extracted material is documented. The method is useful for the routine measurement of plasma retinol, alpha-tocopherol and carotenoids and could also be used in large scale epidemiological studies.

Adult↗
PubMed2001

Carotenoids are degraded by free radicals but do not affect lipid peroxidation in unilamellar liposomes under different oxygen tensions.

It has been questioned whether carotenoids can act as antioxidants in biological membranes. Biological membranes can be modeled for studies of lipid peroxidation using unilamellar liposomes. Both carotenoid depletion and lipid peroxidation were increased with increasing oxygen tension in unilamellar liposomes. Carotenoids in such liposomes were found to be very sensitive to degradation by free radicals generated from iron and 2,2'-azobis(2-amidinopropane) dihydrochloride, but they were not protective against lipid peroxidation. Lycopene and beta-carotene were more sensitive to free radical attack than lutein, zeaxanthin, and beta-cryptoxanthin.

Amidines↗
PubMed2002

Metabolic engineering of xanthophyll content in tomato fruits.

Ripe tomato fruits accumulate significant amounts of the linear carotene lycopene, but only trace amounts of xanthophylls (oxygenated carotenoids). We overexpressed the lycopene beta-cyclase (b-Lcy) and beta-carotene hydroxylase (b-Chy) genes under the control of the fruit-specific Pds promoter. Transgene and protein expression was followed through semi-quantitative reverse transcription-PCR, Western blotting, and enzyme assays. Fruits of the transformants showed a significant increase of beta-carotene, beta-cryptoxanthin and zeaxanthin. The carotenoid composition of leaves remained unaltered. The transgenes and the phenotype are inherited in a dominant Mendelian fashion. This is the first example of successful metabolic engineering of xanthophyll content in tomato fruits.

Arabidopsis↗
PubMed1999

Identification and distribution of dietary precursors of the Drosophila visual pigment chromophore: analysis of carotenoids in wild type and ninaD mutants by HPLC.

A dietary source of retinoid or carotenoid has been shown to be necessary for the biosynthesis of functional visual pigment in flies. In the present study, the larvae or adults of Drosophila melanogaster were administered specific carotenoid-containing diets and high performance liquid chromatography was used to identify and quantify the carotenoids in extracts of wild type and ninaD visual mutant flies. When beta-carotene was fed to larvae, wild type flies were shown to hydroxylate this molecule and to accumulate zeaxanthin and a small amount of beta-cryptoxanthin. Zeaxanthin content was found to increase throughout development and was a major carotenoid peak detected in the adult fly. Carotenoids were twice as effective at mediating zeaxanthin accumulation when provided to larvae versus adults. In the ninaD mutant, zeaxanthin content was shown to be specifically and significantly altered compared to wild type, and was ineffective at mediating visual pigment synthesis when provided to both larval and adult mutant flies. It is proposed that zeaxanthin is the larval storage form for subsequent visual pigment chromophore biosynthesis during pupation, that zeaxanthin or beta-crytoxanthin is the immediate precursor for light-independent chromophore synthesis in the adult, and that the ninaD mutant is defective in this pathway.

Animals↗
PubMed2000

Inhibitory effects of carotenoids on the invasion of rat ascites hepatoma cells in culture.

The effects of carotenoids--alpha-carotene, beta-carotene, lycopene, beta-cryptoxanthin, zeaxanthin, lutein, canthaxanthin, astaxanthin--on the invasion of rat ascites hepatoma AH109A cells were investigated by co-culturing the hepatoma cells with rat mesentery-derived mesothelial cells (M-cells). All the carotenoids examined inhibited AH109A invasion in a dose-dependent manner up to 5 microM. Cancer cells previously cultured with hypoxanthine (HX) and xanthine oxidase (XO) showed a highly invasive activity. Carotenoids, 5 microM of beta-carotene and astaxanthin, suppressed this reactive oxygen species-potentiated invasive capacity by simultaneously treating AH109A cells with the carotenoids, HX and XO. These results suggest that the antioxidative property of these carotenoids may be involved in their anti-invasive action.

Animals↗
PubMed1997

Carotenoids and protection of phospholipids in solution or in liposomes against oxidation by peroxyl radicals: relationship between carotenoid structure and protective ability.

The ability of carotenoids to protect egg-yolk phosphatidylcholine (EYPC) lipids against oxidation by peroxyl radicals generated from azo-initiators was studied. In homogeneous organic solution, all the carotenoids tested ameliorated lipid peroxidation by AMVN, but none was as effective as alpha-tocopherol. Beta-ring carotenoids showed a correlation between protective effect and rate of carotenoid destruction. Beta,beta-Carotene and zeaxanthin, which react with peroxyl radicals at similar rates, gave a similar degree of protection in organic solution. The reactivity and protective ability of the 4,4'-diketocarotenoids, astaxanthin and canthaxanthin was less. Carotenoids incorporated into ordered membrane systems (EYPC liposomes) displayed different protective efficacies. Zeaxanthin and beta-cryptoxanthin were more effective than beta,beta-carotene against oxidation initiated in the aqueous and lipid phases. Astaxanthin and canthaxanthin afforded less protection to the liposomal lipids. Lycopene was destroyed most rapidly but was least effective as an antioxidant. Located in the hydrophobic inner core of the bilayer, the hydrocarbons lycopene and beta,beta-carotene would not be in a position to readily intercept free-radicals entering the membrane from the aqueous phase. Carotenoids with polar end groups span the bilayer with their end groups located near the hydrophobic-hydrophillic interface where free-radical attack from AAPH first occurs. Hydrogen abstraction from C-4 may be one of the mechanisms of carotenoid antioxidant activity in this system. The chemical reactivity of a carotenoid is not the only factor that determines its ability to protect membranes against oxidation. The position and orientation of the carotenoid in the bilayer is also of importance.

Azo Compounds↗
PubMed2003

Effects of a high monounsaturated fat, tomato-rich diet on serum levels of lycopene.

OBJECTIVE: To compare the effect of a modified fat, monounsaturated-fat-enriched diet and a high-carbohydrate low-fat diet with high lycopene content on the serum concentration of lycopene and other carotenoids. DESIGN: A randomised crossover dietary intervention study. SETTING: Melbourne, Australia--Healthy free-living men. SUBJECTS: A total of 13 healthy males between the age of 20 and 70 y, recruited via advertisements in newspapers and university newsletter. INTERVENTION: A randomised dietary intervention with two diets of 14 days each. The two diets were--(1) high-fat monounsaturated-fat-enriched (MUFA) and (2) high-carbohydrate low-fat (HCLF). Both the diets contained the same basic foods and a controlled carotenoid content high in lycopene. RESULTS: A significant increase in serum total lycopene occurred, by 126% on the MUFA diet (P <0.001) and 108% on the HCLF diet (P=0.001). A reduction in serum cryptoxanthin (27% on MUFA diet and 25% on HCLF) and alpha-carotene (43% on the MUFA diet and 25% on the HCLF diet) was observed. No change was observed for the other carotenoids. Comparing the end of the two diets, no statistically significant difference was observed for lycopene or the other carotenoids. CONCLUSION: In all, 15% of energy from fat or 38% of energy from fat (predominantly monounsaturated fat) in the diet does not have a significant differential effect on serum lycopene. SPONSORSHIP: The study was partially funded by the Grains Research Development Corporation, Canberra and Meadow Lea Foods Ltd, Mascot, Australia. HJ Heinz, Melbourne, Australia provided the tomato products and some funds for their carotenoid analysis.

Adult↗
PubMed2003

Low plasma concentrations of diet-derived antioxidants in association with microalbuminuria in Indigenous Australian populations.

Microalbuminuria is a risk factor for renal and cardiovascular diseases. Oxidant stress may contribute to vascular disease risk by promoting damage to renal and vascular tissues. This study examined the associations of plasma levels of diet-derived antioxidants with albuminuria in Australian population groups at high risk of renal and cardiovascular disease. Data on microalbuminuria and diet-derived plasma antioxidants were drawn from results of cross-sectional community-based risk factor surveys of Aboriginal and Torres Strait Islander peoples (n =698, 15 years and older). Prevalence of microalbuminuria ranged from 17-21%. After adjustment for age, gender, body mass index, diabetes, smoking status, plasma lipids and blood pressure, microalbuminuria was associated with significantly lower plasma concentrations of lycopene (-29%; P <0.001), beta-carotene (-22%; P <0.001), alpha-carotene (-22%; P <0.001) and cryptoxanthin (-17%; P <0.001) compared with normalbuminuric persons. Significant associations of microalbuminuria with plasma concentrations of alpha-tocopherol, retinol, lutein plus zeaxanthin and homocysteine were absent. The data are consistent with a protective effect of diets rich in carotenoids on vascular endothelium and/or renal tissues, and support the need for interventions to address affordable food supplies and dietary quality among Indigenous Australians.

Adolescent↗
PubMed1994

The relations between cervical cancer and serological markers of nutritional status.

We evaluated whether differences in serological nutrient indicators between cases and controls were likely to be due to different usual levels for cases or to altered metabolism due to disease. Blood samples obtained as part of a case-control study of invasive cervical cancer conducted in Latin America were evaluated for case-control differences and for trends with stage of disease. Serum alpha- and beta-carotene, cryptoxanthin, and alpha- and gamma-tocopherol showed no trend with extent of disease, although Stage IV cases had lower alpha- and beta-carotene values than did other cases. A slight trend of decreasing values with stage was observed for serum retinol, lycopene, and lutein. For cholesterol and triglyceride concentrations, an inverse trend was observed with stage of disease, which suggested a clinical effect of the disease on blood lipids. Adjustment for smoking, alcohol intake, or oral contraceptive use did not alter observed relations, nor was there evidence that the altered blood nutrient levels differed by histological type. These data suggest that serum values for some carotenoids from Stage I, II, and III cervical cancer are suitable for etiological studies, but spurious results may be obtained if late-stage cases are included. Evidence of trends with severity of disease for cholesterol and triglycerides, and possibly for retinol, lycopene, and lutein, suggest that special attention be given to disease effects of these nutrients in studies of cervical cancer.

Adult↗