The crtS gene of Xanthophyllomyces dendrorhous encodes a novel cytochrome-P450 hydroxylase involved in the conversion of β-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.

Carotenoid-membrane interactions in liposomes: effect of dipolar, monopolar, and nonpolar carotenoids

Electron paramagnetic resonance (EPR) spin-labeling methods were used to study the effects of carotenoids on the physical properties of saturated phosphatidylcholine (PC) membranes to evaluate the contribution of the terminal hydroxyl groups of xanthophyll molecules to the carotenoid-membrane interaction. Effects of the dipolar, terminally dihydroxylated carotenoid lutein on membrane phase transition, fluidity, order, and polarity were compared with those of monopolar (beta-cryptoxanthin) and nonpolar (beta-carotene) carotenoids. These effects were monitored at the membrane center as a function of the amount of the carotenoid added to the sample and as a function of temperature for fluid-phase membranes. PC membranes with different thickness (from 12 to 22 carbons in alkyl chains) were used. Carotenoids shifted to lower temperatures and broadened the main phase transition of PC membranes. They decreased the membrane fluidity and increased the order of alkyl chains. Carotenoids also increased the hydrophobicity of the membrane interior. These effects were the strongest for lutein, significantly weaker for beta-cryptoxanthin, and negligible for beta-carotene. They decreased with the increase of the membrane thickness. Presented results suggest that anchoring of carotenoid molecules at the opposite membrane surfaces by polar hydroxyl groups is significant in enhancing their effects on membrane properties. This manuscript also shows the ability of EPR spin-labeling methods to monitor different membrane properties that can be applied in biotechnological studies with the use of liposomes.

Oral administration of beta-cryptoxanthin prevents bone loss in ovariectomized rats

The effect of beta-cryptoxanthin, a kind of carotenoid, on ovariectomy-induced bone loss was investigated. beta-cryptoxanthin was isolated from Satsuma mandarin (Citrus unshu. MARC). beta-cryptoxanthin (5 or 10 microg/100 g body weight) was orally administered once daily for 3 months to ovariectomized (OVX) rats. OVX induced a significant increase in body weight and a significant decrease in serum calcium and inorganic phosphorus concentrations as compared with those of sham-operated (control) rats. These alterations induced by OVX were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g). The analysis using a peripheral quantitative computed tomography (pQCT) showed that OVX induced a significant decrease in mineral content and mineral density in the femoral-diaphyseal and -metaphyseal tissues and polar strength strain index in the metaphyseal tissues. These decreases were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g). Moreover, OVX induced a significant decrease in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues and deoxyribonucleic acid (DNA) content in the metaphyseal tissues. These decreases were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g). This study demonstrates that beta-cryptoxanthin has a preventive effect on OVX-induced bone loss in vivo.

Reconstitution of β-carotene hydroxylase activity of thermostable CYP175A1 monooxygenase

CYP175A1 is a thermostable P450 Monooxygenase from Thermus thermophilus HB27, demonstrating in vivo activity towards beta-carotene. Activity of CYP175A1 was reconstituted in vitro using artificial electron transport proteins. First results were obtained in the mixture with a crude Escherichia coli cell extract at 37 degrees C. In this system, beta-carotene was hydroxylated to beta-cryptoxanthin. The result indicated the presence of electron transport enzymes among the E. coli proteins, which are suitable for CYP175A1. However, upon in vitro reconstitution of CYP175A1 activity with purified recombinant flavodoxin and flavodoxin reductase from E. coli, only very low beta-cryptoxanthin production was observed. Remarkably, with another artificial electron transport system, putidaredoxin and putidaredoxin reductase from Pseudomonas putida, purified CYP175A1 enzyme hydroxylated beta-carotene at 3- and also 3'-positions, resulting in beta-cryptoxanthin and zeaxanthin. Under the optimal reaction conditions, the turnover rate of the enzyme reached 0.23 nmol beta-cryptoxanthin produced per nmol P450 per min.

Serum carotenoid concentrations are inversely associated with serum aminotransferases in hyperglycemic subjects

Hyperglycemia increases the generation of free radicals by glucose auto-oxidation, and the increment of free radicals may lead to liver cell damage. In this study, we tested the hypothesis that hyperglycemia-induced increases of serum liver enzymes among its physiological concentration would be inversely associated with serum antioxidant carotenoid level. Study subjects were 857 male and female Japanese who had received health examinations in 2003. Those with a history of liver disease and excessive alcohol drinkers were excluded. The associations of serum six-carotenoid concentrations with serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) stratified by glucose tolerance status were evaluated cross-sectionally. Serum AST and ALT concentrations in the groups of impaired fasting glucose (IFG) and diabetes were significantly higher than those in the normal group. The multivariate-adjusted means of the serum AST and ALT concentrations in IFG and diabetes group were significantly low in accordance with the tertiles of the serum beta-cryptoxanthin and beta-carotene concentrations. The most inverse association of serum liver enzyme and carotenoid concentration was observed in beta-cryptoxanthin. Antioxidant carotenoid, especially beta-cryptoxanthin, may act a deterrent substance against increasing the serum aminotransferase in the earlier pathogenesis of liver dysfunction among hyperglycemic subjects.

Oral Administration in Combination with Zinc Enhances .BETA.-Cryptoxanthin-Induced Anabolic Effects on Bone Components in the Femoral Tissues of Rats in Vivo

The effects of combined beta-cryptoxanthin and zinc on bone components in the femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues of rats in vivo were investigated. Rats were orally administered either vehicle, beta-cryptoxanthin (5 or 10 microg/100 g body weight), zinc sulfate (0.1 or 0.5 mg Zn/100 g), or their combination once a day for 7 d. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal tissues was not significantly altered by the administration of beta-cryptoxanthin (5 microg/100 g) or zinc (0.1 or 0.5 mg/100 g). Combined administration of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g) caused a synergistic increase in calcium content, alkaline phosphatase activity, and DNA content in the diaphyseal tissues. The effect of beta-cryptoxanthin (5 or 10 microg/100 g) in increasing calcium and DNA contents in the metaphyseal tissues was significantly enhanced by the combined administration of zinc (0.1 or 0.5 mg/100 g), but did not have a significant effect on the metaphyseal components. The metaphyseal alkaline phosphatase activity was markedly increased by the combination of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g). This study demonstrates that the oral administration of the combination of zinc at lower doses synergistically enhances beta-cryptoxanthin-induced anabolic effects on bone components in the femoral tissues of rats in vivo.

beta-cryptoxanthin stimulates cell differentiation and mineralization in osteoblastic MC3T3-E1 cells

The effect of beta-cryptoxanthin, a kind of carotenoid, on cell differentiation and mineralization in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 72 h in a minimum essential medium containing 10% fetal bovine serum (FBS), and the cells with subconfluency were changed to a medium containing either vehicle or beta-cryptoxanthin (10(-8) to 10(-6) M) without FBS. Cells were cultured for 3 to 21 days. Gene expression in osteoblastic cells was determined using reverse transcription-polymerase chain reaction (RT-PCR). Culture with beta-cryptoxanthin (10(-7) or 10(-6) M) for 3 days caused a significant increase in Runx2 type 1, Runx2 type 2, alpha1 (I) collagen, and alkaline phosphatase mRNA levels in osteoblastic cells. These increases were completely blocked in the presence of cycloheximide, an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), an inhibitor of transcriptional activity. Meanwhile, vitamin A (10(-6) M) did not have a significant effect on Runx2 type 1 mRNA expression in the cells. The effect of beta-cryptoxanthin (10(-6) M) in stimulating Runx2 type 1 and alpha1 (I) collagen mRNA levels, protein content, and alkaline phosphatase activity in the cells was also seen in the presence of vitamin A (10(-6) M), suggesting that the mode of beta-cryptoxanthin action differs from that of vitamin A. Prolonged culture with beta-cryptoxanthin (10(-6) M) for 3 to 21 days caused a significant increase in cell number, deoxyribonucleic acid (DNA) content, protein content, and alkaline phosphatase activity in osteoblastic cells, suggesting that beta-cryptoxanthin stimulates cell proliferation and differentiation. Moreover, culture with beta-cryptoxanthin (10(-7) or 10(-6) M) for 5 to 21 days caused a remarkable increase in mineralization. This study demonstrates that beta-cryptoxanthin has a stimulatory effect on cell differentiation and mineralization due to enhancing gene expression of proteins, which involve in bone formation in osteoblastic MC3T3-E1 cells.

Synergistic effect of beta-cryptoxanthin and zinc sulfate on the bone component in rat femoral tissues in vitro: the unique anabolic effect with zinc

The effect of the combination of beta-cryptoxanthin and zinc sulfate (zinc) on bone components in the femoral-diaphyseal and -metaphyseal tissues of young rats in vitro was investigated. Bone tissues were cultured for 48 h in a serum-free Dulbecco's modified Eagle's medium containing either vehicle, beta-cryptoxanthin (10(-9)-10(-7) M) or zinc sulfate (10(-6)-10(-4) M). The presence of beta-cryptoxanthin (10(-9) M) or zinc (10(-6) M) did not have a significant effect on calcium content in the femoral-diaphyseal or -metaphyseal tissues. However, culture which combined beta-cryptoxanthin (10(-9) M) and zinc (10(-6) M) caused a significant increase in calcium content in the femoral-diaphyseal and -metaphyseal tissues. Such an effect was not observed by the combination of beta-cryptoxanthin (10(-9) M) plus genistein (10(-6) M) or menaquinone-7 (10(-6) M), or zinc (10(-6) M) plus genistein (10(-6) M) or menaquinone-7 (10(-6) M). Also, the combination of beta-cryptoxanthin (10(-9) M) plus zinc (10(-6) M) caused a remarkable increase in alkaline phosphatase activity and deoxyribonucleic acid (DNA) in the femoral-diaphyseal and -metaphyseal tissues, while their application alone did not have an effect on the enzyme activity or DNA content in the femoral tissues. The effect of the combination of beta-cryptoxanthin (10(-9) M) plus zinc (10(-6) M) in increasing calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues was completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DBR), an inhibitor of transcriptional activity. This study demonstrates that the combination of beta-cryptoxanthin and zinc at a lower concentration has a synergistic effect on bone components in vitro.

Relationship Between Plasma Carotenoids and Prostate Cancer

Carotenoids, particularly lycopene, are thought to decrease prostate cancer risk, but the relationship between plasma carotenoid concentrations and risk in various populations has not been well characterized. Comparing 118 non-Hispanic Caucasian men mainly from southeast Texas with nonmetastatic prostate cancer with 52 healthy men from the same area, we conducted a case-control analysis evaluating associations between risk and plasma levels of total carotenoids, beta-cryptoxanthin, alpha- and trans-beta-carotene, lutein and zeaxanthin, total lycopenes, trans-lycopene, total cis-lycopenes, and cis-lycopene isoforms 1, 2, 3, and 5. Risk for men with high plasma levels of alpha-carotene, trans-beta-carotene, beta-cryptoxanthin, and lutein and zeaxanthin was less than half that for those with lower levels. In contrast, we observed no significant associations for total lycopenes, all-trans-lycopene, and cis-lycopene isomer peaks 2, 3, and 5, although high levels of cis-lycopene isomer peak 1 were inversely associated with risk. Analysis of men with aggressive disease (Gleason scores of > or =7, n = 88) vs. less aggressive cases (Gleason scores of <7, n = 30) failed to reveal significant associations between carotenoid levels and the risk of diagnosis with aggressive disease. These findings suggest that, in these men, higher circulating levels of alpha-cryptoxanthin, alpha-carotene, trans-beta-carotene, and lutein and zeaxanthin may contribute to lower prostate cancer risk but not to disease progression.

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.

Plasma carotenoids as biomarkers of intake of fruits and vegetables: individual-level correlations in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

The aim in this study was to assess the association between individual plasma carotenoid levels (alpha-carotene, beta-carotene, lycopene, beta-cryptoxanthin, lutein, zeaxanthin) and fruit and vegetable intakes recorded by a calibrated food questionnaire (FQ) and 24-h dietary recall records (24HDR) in nine different European countries with diverse populations and widely varying intakes of plant foods.

DESIGN

A stratified random subsample of 3089 men and women from nine countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC), who had provided blood samples and dietary and other lifestyle information between 1992 and 2000, were included.

RESULTS

beta-Cryptoxanthin was most strongly correlated with total fruits (FQ r = 0.52, 24HDR r = 0.39), lycopene with tomato and tomato products (FQ r = 0.38, 24HDR r = 0.25), and alpha-carotene with intake of root vegetables (r = 0.39) and of total carrots (r = 0.38) for FQ only. Based on diet measured by FQ and adjusting for possible confounding by body mass index (BMI), age, gender, smoking status, alcohol intake, and energy intake, the strongest predictors of individual plasma carotenoid levels were fruits (R(partial)(2) = 17.2%) for beta-cryptoxanthin, total carrots ((partial)(2) = 13.4%) and root vegetables (R(partial)(2) = 13.3%) for alpha-carotene, and tomato products (R(partial)(2) = 13.8%) for lycopene. For 24HDR, the highest R(partial)(2) was for fruits in relation to beta-cryptoxanthin (7.9%).

CONCLUSIONS

Intakes of specific fruits and vegetables as measured by food questionnaires are good predictors of certain individual plasma carotenoid levels in our multicentre European study. At individual subject levels, FQ measurements of fruits, root vegetables and carrots, and tomato products are, respectively, good predictors of beta-cryptoxanthin, alpha-carotene, and lycopene in plasma.

Diabetes mellitus and serum carotenoids: findings of a population-based study in Queensland, Australia

BACKGROUND

Epidemiologic evidence suggests that serum carotenoids are potent antioxidants and may play a protective role in the development of chronic diseases including cancers, cardiovascular disease, and inflammatory diseases. The role of these antioxidants in the pathogenesis of diabetes mellitus remains unclear.

OBJECTIVE

This study examined data from a cross-sectional survey to investigate the association between serum carotenoids and type 2 diabetes.

DESIGN

Study participants were adults aged > or = 25 y (n = 1597) from 6 randomly selected cities and towns in Queensland, Australia. Study examinations conducted between October and December 2000 included fasting plasma glucose, an oral-glucose-tolerance test, and measurement of the serum concentrations of 5 carotenoid compounds.

RESULTS

Mean 2-h postload plasma glucose and fasting insulin concentrations decreased significantly with increasing quintiles of the 5 serum carotenoids--alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, and lycopene. Geometric mean concentrations for all serum carotenoids decreased (all decreases were significant except that of lycopene) with declining glucose tolerance status. Beta-carotene had the greatest decrease, to geometric means of 0.59, 0.50, and 0.42 micromol/L in persons with normal glucose tolerance, impaired glucose metabolism, and type 2 diabetes, respectively (P < 0.01 for linear trend), after control for potential confounders.

CONCLUSIONS

Serum carotenoids are inversely associated with type 2 diabetes and impaired glucose metabolism. Randomized trials of diets high in carotenoid-rich vegetables and fruit are needed to confirm these results and those from other observational studies. Such evidence would have very important implications for the prevention of diabetes.

Cryptoxanthin structural isomers in oranges, orange juice, and other fruits

Citrus fruits contain a wide range of bioactive compounds. Their carotenoid fraction is inter alia dominated by structural cryptoxanthin isomers as beta-cryptoxanthin and zeinoxanthin. Both xanthophylls were identified in saponified citrus fruit extracts by comparison to reference compounds extracted from corn and by their typical fragmentation pattern in LC-(APCI)MS analyses. alpha-Cryptoxanthin, another structural cryptoxanthin isomer usually found in carrot leaves, was not identified in the citrus fruits studied. Cryptoxanthin concentrations of direct orange juices (D) and reconstituted juices (C) were compared. Although the respective mean values [beta-cryptoxanthin, 62 (C) versus 110 microg/100 g (D); zeinoxanthin, 22 (C) versus 37 microg/100 g (D)] were statistically distinguishable (P < 0.05%), a doubtless classification is not possible because the concentration ranges overlap. To identify esters of structural cryptoxanthin isomers in native orange juice extracts, four saturated acyl esters were synthesized. LC-(APCI)MS studies revealed for the first time that the dominant acylation partners of both xanthophylls were C12:0, C14:0, and C16:0 in nearly equal amounts of roughly one-third, whereas C10:0 and C18:1 were present at lower extents of 5-14%; other acylation partners were not identified. The presented method is appropriate to gain deeper insight into the pattern of structural cryptoxanthin isomers of citrus fruits. Knowledge of acylated cryptoxanthin isomers may be important in the evaluation of the bioavailability of individual esters in future human digestion studies.

Identification of zeinoxanthin in orange juices

The monohydroxycarotenoid fraction of orange juice has been isolated by TLC and studied to determine whether the carotenoid accompanying beta-cryptoxanthin was alpha-cryptoxanthin or zeinoxanthin. The provitamin A carotenoid alpha-cryptoxanthin has been widely reported in orange juice, although its identification has been carried out mainly on the basis of its spectral features, which are virtually identical with those of its non-provitamin A isomer, zeinoxanthin. As a result of a study of the UV-vis and mass spectra of the monohydroxycarotenoid fraction and of the methylation test, it was concluded that the carotenoid accompanying beta-cryptoxanthin was the non-provitamin A carotenoid zeinoxanthin.

Dietary beta-cryptoxanthin and inflammatory polyarthritis: results from a population-based prospective study

BACKGROUND

Epidemiologic studies suggest that the antioxidant potential of dietary carotenoids may protect against the oxidative damage that can result in inflammation.

OBJECTIVE

We investigated the hypothesis that some dietary carotenoids are associated with a reduced risk of developing inflammatory polyarthritis (IP).

DESIGN

The European Prospective Investigation of Cancer Incidence (EPIC)-Norfolk study is a population-based, prospective study of >25,000 subjects who completed a baseline 7-d diet diary and were followed up to identify new cases of IP, which was defined as synovitis that affected > or = 2 joint groups. Dietary carotenoid intakes were computed from the diet diaries of these subjects, and a nested, case-control analysis was undertaken to compare carotenoid intake between case subjects and age- and sex-matched control subjects.

RESULTS

Eighty-eight incident cases of IP that occurred in the population surveyed were ascertained via the Norfolk Arthritis Register. The mean daily intakes of zeaxanthin and beta-cryptoxanthin were 20% and 40% lower, respectively, in the cases than in the 176 controls, but there were no significant differences in the intakes of either lutein or lycopene. Those subjects in the top one-third of intake of zeaxanthin and beta-cryptoxanthin were at a lower risk of developing IP than were subjects in the lowest one-third [odds ratios (95% CI): 0.48 (0.24, 0.94) and 0.51 (0.25, 1.02) for zeaxanthin and beta-cryptoxanthin, respectively]. The association with beta-cryptoxanthin was significant after adjustments were made for total energy and protein intakes and for cigarette smoking.

CONCLUSION

These data are consistent with previous evidence showing that a modest increase in beta-cryptoxanthin intake, equivalent to one glass of freshly squeezed orange juice per day, is associated with a reduced risk of developing inflammatory disorders such as rheumatoid arthritis.

Serum carotenoid concentrations are inversely associated with serum aminotransferases in hyperglycemic subjects

Hyperglycemia increases the generation of free radicals by glucose auto-oxidation, and the increment of free radicals may lead to liver cell damage. In this study, we tested the hypothesis that hyperglycemia-induced increases of serum liver enzymes among its physiological concentration would be inversely associated with serum antioxidant carotenoid level. Study subjects were 857 male and female Japanese who had received health examinations in 2003. Those with a history of liver disease and excessive alcohol drinkers were excluded. The associations of serum six-carotenoid concentrations with serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) stratified by glucose tolerance status were evaluated cross-sectionally. Serum AST and ALT concentrations in the groups of impaired fasting glucose (IFG) and diabetes were significantly higher than those in the normal group. The multivariate-adjusted means of the serum AST and ALT concentrations in IFG and diabetes group were significantly low in accordance with the tertiles of the serum beta-cryptoxanthin and beta-carotene concentrations. The most inverse association of serum liver enzyme and carotenoid concentration was observed in beta-cryptoxanthin. Antioxidant carotenoid, especially beta-cryptoxanthin, may act a deterrent substance against increasing the serum aminotransferase in the earlier pathogenesis of liver dysfunction among hyperglycemic subjects.

A study to determine plasma antioxidant concentrations in patients with Barrett's oesophagus

BACKGROUND

Dietary questionnaire studies have suggested that patients with oesophageal adenocarcinoma are deficient in antioxidants. It is not known whether the same holds true for patients with the precursor lesion, Barrett's oesophagus.

AIMS

To evaluate the hypothesis that patients with Barrett's oesophagus are deficient in antioxidants compared with patients without evidence of Barrett's oesophagus.

PATIENTS AND METHODS

Plasma antioxidant profiles (copper, selenium, zinc; vitamins A, C, and E; carotenoids) were determined for patients with Barrett's oesophagus (n = 36), patients with erosive oesophagitis (n = 32), and patient controls (n = 35).

RESULTS

Patients with Barrett's oesophagus had significantly lower plasma concentrations of selenium, vitamin C, beta cryptoxanthine, and xanthophyll compared with the other groups.

CONCLUSIONS

This study confirms the hypothesis that patients with Barrett's oesophagus are deficient in certain antioxidants.

Chromatographic analysis of carotenol fatty acid esters in Physalis alkekengi and Hippophae rhamnoides

The carotenol fatty acid esters of two potentially valuable sources of plant carotenoids, sepals of Physalis alkekengi (Chinese lantern) and fruits of Hippophae rhamnoides (sea buckthorn), were separated by column chromatography and identified by HPLC-DAD and HPLC-MS. A chemical and an enzymatic hydrolysis were employed to identify the parent carotenoids and to remove the lipid components. Zeaxanthin and beta-cryptoxanthin esters represented the main fraction in P. alkekengi sepals and an important one in H. rhamnoides fruits. Beta-Cryptoxanthin palmitate and zeaxanthin dipalmitate were identified as major compounds in both plants. In P. alkekengi, the carotenoids were mainly (> 90%) esterified with palmitic acid, and a high proportion (> 80%) of saturated medium chain fatty acids was found (by GC-MS) in the total lipid extract. Although the total lipid extract of H. rhamnoides contained significant amounts of unsaturated fatty acids, especially oleic and palmitoleic acids, the xanthophylls were mainly esterified with saturated fatty acids. The oleoresins of both species represent potential sources of carotenoid esters and can be used as food additives, cosmetic ingredients or nutraceuticals.

Association between serum concentrations of micronutrients and lower urinary tract symptoms in older men in the Third National Health and Nutrition Examination Survey

OBJECTIVES

To evaluate the association of serum micronutrients with lower urinary tract symptoms (LUTS).

METHODS

We included 2497 men, 60 years old and older, who participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994 and for whom serum concentrations of vitamins A, C, and E, carotenoids, and selenium had been measured previously. Cases were men with three or four of the following symptoms: nocturia, hesitancy, incomplete emptying, and weak stream, but who had never undergone noncancer prostate surgery. Controls were men without symptoms, who had never undergone noncancer prostate surgery. We adjusted for age and race in logistic regression models and used sampling weights.

RESULTS

Serum concentrations of vitamin E (P = 0.03), lycopene (P = 0.06), and selenium (P = 0.03) were lower in men with LUTS compared with controls. Men in the top four quintiles of vitamin E, lycopene, and selenium had a nonstatistically significant 25% to 50% reduced odds of LUTS compared with men in the bottom quintile. Inverse associations were not seen for the other carotenoids or vitamin A. A high serum vitamin C concentration was associated with a lower odds of LUTS in current smokers, but with a nonstatistically significant greater odds in those who never smoked and in former smokers.

CONCLUSIONS

Greater circulating concentrations of vitamin E, lycopene, and selenium, antioxidant micronutrients that are supported in published reports as protecting against prostate cancer, were observed also to be inversely associated with LUTS. The effect modification of the association with vitamin C by cigarette smoking warrants additional examination.

beta-Cryptoxanthin stimulates cell proliferation and transcriptional activity in osteoblastic MC3T3-E1 cells

The carotenoid beta-cryptoxanthin has been shown to have a stimulatory effect on bone formation in rat bone tissues in vitro. The effect of beta-cryptoxanthin in osteoblastic cells in vitro was investigated. Osteoblastic MC3T3-E1 cells were cultured for 72 h in alpha-minimal essential medium containing 10% fetal bovine sereum (FBS) to reach subconfluent monolayers. After culture, the medium was changed, then beta-cryptoxanthin (10(-8) to 10(-6) M) was added in the culture medium without FBS, and the cells were cultured for an additional 24, 48, or 72 h. The proliferation of osteoblastic cells was significantly enhanced in the presence of beta-cryptoxanthin (10(-8) to 10(-6) M), when it was cultured for 48 or 72 h in medium containing 10% FBS. When osteoblastic cells with subconfluency were cultured for 48 or 72 h in FBS free-medium containing beta-cryptoxanthin (10(-8) to 10(-6) M), alkaline phosphatase activity or deoxyribonucleic acid (DNA) content in the cells was significantly increased. Also, protein content in the cells was significantly increased by culture with 10(-6) M beta-cryptoxanthin for 48 or 72 h. The effect of beta-cryptoxanthin (10(-6) M) in increasing protein content, alkaline phosphatase activity, or DNA content in the cells was significantly blocked in the presence of staurosporine (10(-6) M) or PD98059 (10(-6) M), which is an inhibitor of protein kinases. The stimulatory effect of beta-cryptoxanthin (10(-6) M) on cellular biochemical components was completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB; 10(-9) M), an inhibitor of transcriptional activity. The expressions of insulin-like growth factor (IGF)-I and transforming growth factor (TGF)-beta1 mRNAs were demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) analysis in osteoblastic cells using mouse IGF-I or TGF-beta1-specific primers. These expressions were significantly raised in the presence of beta-cryptoxanthin (10(-6) M). This study demonstrates that beta-cryptoxanthin has a stimulatory effect on cell proliferation and biochemical components in osteoclastic MC3T3-E1 cells, and that the carotenoid can stimulate transcriptional activity in the cells.

Multiple linear regression analysis of the seasonal changes in the serum concentration of beta-cryptoxanthin

Beta-cryptoxanthin (beta-CRX) is a carotenoid pigment found in Satsuma mandarin (Citrus unshiu Marc.) fruit, which is heavily produced in Japan. In this study, we evaluated the seasonal changes in the serum beta-CRX level and investigated predictors of serum beta-CRX level by multiple linear regression analysis. Blood tests and self-administered questionnaires were used every other month for one year. The subjects were healthy volunteers, 15 males and 12 females. The serum beta-CRX levels increased dramatically as the intake of Satsuma mandarin increased; the maximum increase was noted in January. Multiple linear regression analysis showed that, in males, the serum beta-CRX level could be predicted by Satsuma mandarin intake, age and the month of blood sampling; however, it was inversely associated with alcohol and smoking habits. Conversely, in females, the serum beta-CRX concentration could be predicted by Satsuma mandarin intake, the month of blood sampling and age; however, it was inversely associated with body mass index. The results of multiple linear regression analysis suggest that the serum beta-CRX levels can be used to evaluate the intake volume of Satsuma mandarin. Furthermore, beta-CRX is a useful biomarker to estimate the beneficial effects of Satsuma mandarin intake in epidemiological studies.

Plasma carotenoid levels in Dutch men and women, and the relation with vegetable and fruit consumption

OBJECTIVE

Fruit and vegetable intake is inversely associated with cancer risk in many epidemiological studies. Accurate assessment of consumption of these foods is difficult, and biomarkers of intake would overcome several drawbacks of currently used dietary assessment methods. Therefore, we investigated the relation between plasma carotenoids and usual vegetable and fruit intake.

DESIGN

Plasma carotenoid concentrations were measured and vegetable, fruit and juice consumption was assessed by a food frequency questionnaire (FFQ) in a random sample of 591 Dutch men and women aged 20-59 y from the MORGEN-project, one of the contributions to the European Prospective Investigation into Cancer and Nutrition (EPIC)-study.

RESULTS

In this sample of the general Dutch population, in both genders, relative to the other carotenoids, plasma beta-cryptoxanthin was the best indicator for fruit intake, and for the sum of vegetable, fruit and juice intake, while lutein concentrations best reflected intake of vegetables, although quartiles of intake were not consistently separated. Since levels of lycopene were not associated with any of the main food groups examined, associations with total carotenoids improved when excluding lycopene, and monotonously increasing plasma levels were seen for intakes of vegetables, of fruits, and of the sum of vegetables, fruits and juices. Several vegetable types and orange/grapefruit juice were associated with plasma levels of one of the carotenoids.

CONCLUSION

Plasma carotenoids were only crude indicators of vegetable and fruit intake as assessed by a FFQ; beta-cryptoxanthin for fruit intake and lutein for vegetable intake. None of the plasma carotenoids could distinguish all four quartiles of vegetables, fruit and/or juice intake.

Oral Administration of .BETA.-Cryptoxanthin Prevents Bone Loss in Streptozotocin-Diabetic Rats in Vivo

The effects of beta-cryptoxanthin, a carotenoid, on bone components in the femoral-diaphyseal and -metaphyseal tissues of streptozotocin (STZ)-diabetic rats was investigated. Rats received a single subcutaneous administration of STZ (6.0 mg/100 g body weight), and then the animal were orally administered beta-cryptoxanthin (5 or 10 microg/100 g body weight) once daily for 7 or 14 d. The administration of STZ caused a significant decrease in body weight and a significant increase in serum glucose, triglyceride, and calcium levels, indicating a diabetic state. These alterations were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g) for 14 d. The administration of beta-cryptoxanthin (5 or 10 microg/100 g) to normal rats for 14 d did not have a significant effect on body weight or on serum glucose, triglyceride, and calcium levels. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues were significantly decreased in STZ-diabetic rats. These decreases were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g) for 14 d. The administration of beta-cryptoxanthin to normal rats for 14 d caused a significant increase in calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues. This study demonstrates that the intake of beta-cryptoxanthin has a preventive effect on bone loss in STZ-diabetic rats.

Carotenoid Depletion in Serum of Young Type-1 Diabetics Fed Low-Carotenoid Diets

BACKGROUND/AIMS

Type-1 diabetics have been considered to be at risk for increased oxidative stress which has been implicated in the development of long-term diabetes complications. Evidence suggests that antioxidant activity may be an important mechanism by which carotenoids could confer protection in human health. Our aim was to compare the serum carotenoid depletion rate in type-1 diabetics and control subjects consuming low-carotenoid diets.

METHODS

Ten type-1 diabetics and 8 controls followed a very low-carotenoid diet for 21 days. Dietary intake was recorded daily and fasting blood samples collected at baseline and after 1, 2, 3, 6, 11, 15, 16, 17, and 21 days. Individual carotenoids in serum were analyzed by a validated HPLC method.

RESULTS

In both groups, carotenoid intake was less than 5% of the season-adjusted carotenoid reference intake. These diets resulted in decreased serum carotenoid levels in both groups, although depletion curves, final mean concentrations and the estimated half-life of carotenoids in serum revealed no differences between type-1 diabetics and controls. Levels of other minor serum carotenoids, cis-isomers and keto-carotenoids, also decreased whereas serum retinol and alpha- and gamma-tocopherol did not change during the study.

CONCLUSION

Upon a low-carotenoid intake, the depletion rate of carotenoids in serum in young type-1 diabetics does not differ from that observed in matched related controls.