首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
We investigated the presence of different carotenoids in male human subject after the ingestion of paprika juice, and identified capsanthin, capsanthone, cucurbitaxanthin A, 11-cis-capsanthin, lutein and zeaxanthin in the human plasma. These results suggest that capsanthone and 11-cis-capsanthin might be as important as capsanthin for human health.  相似文献   

2.
Epidemiological and animal studies have provided evidence that dietary carotenoids may reduce the risk of certain types of cancer. An inhibitory activity of oxygenated carotenoid capsanthin, a potent antioxidant, and paprika juice rich in capsanthin (3.54 mg/100 ml) against colon carcinogenesis was investigated in F344 rats. In Experiment I (short-term assay), six rats each were given a gavage of 5 mg, 0.2 mg, or 0.008 mg capsanthin six times a week for Weeks 2-6 after receiving three intrarectal doses of 4 mg N-methylnitrosourea in Week 1. The number of colonic aberrant crypt foci, preneoplastic lesions, at Week 6 was significantly fewer (by 42%) in the 0.2 mg capsanthin group, but not in other groups, than the control group. In Experiment II (long-term assay), five groups of 30 or 25 rats each received an intrarectal dose of 2 mg N-methylnitrosourea three times a week for Weeks 1-3, and had either of 10 p.p.m. or 2 p.p.m. capsanthin solutions, 1:2.5 and 1:16.7 diluted solution of paprika juice (containing 10 p.p.m. or 2 p.p.m. capsanthin), and tap water (control fluid) as drinking fluid throughout the experiment. The experimental groups were fed 0.2 mg or 0.04 mg capsanthin/day/rat. The colon cancer incidence at Week 30 was significantly lower in the highly diluted paprika juice group (40%), but not in the moderately diluted paprika juice group (60%) and the capsanthin solution groups (68% and 68%) than the control group (83%). The results suggested that paprika juice may affect colon carcinogenesis. However, capsanthin alone failed to inhibit colon tumorigenesis, in spite of suppression of aberrant crypt foci formation in the short-term assay. Further studies are needed to explain this discrepancy.  相似文献   

3.
4.
We investigated the presence of different carotenoids in male human subject after the ingestion of paprika juice, and identified capsanthin, capsanthone, cucurbitaxanthin A, 11-cis-capsanthin, lutein and zeaxanthin in the human plasma. These results suggest that capsanthone and 11-cis-capsanthin might be as important as capsanthin for human health.  相似文献   

5.
Food-additive grades of capsanthin, lutein, lycopene, and β-carotene dispersed in aqueous solutions were photo-irradiated using a Xenon weather meter, and the levels of carotenoids were measured by HPLC and the absorbance method. Capsanthin photo-degraded more rapidly than the carotenoids tested, with less oxygen consumption. Unlike carotenes, capsanthin was partially converted into analogous colored compounds during degradation.  相似文献   

6.
beta-Carotene and other xanthophylls present in pepper fruit as both free and esterified forms were oxidized using a free radical initiator (2,2'-azo-bis-isobutyronitrile). Capsorubin was degraded most slowly, followed by zeaxanthin, capsanthin, and beta-carotene. The presence of keto groups at the ends of the polyene chain could be a structural factor contributing to this difference in reactivity. It was also shown that whereas capsanthin and its esters and capsorubin and its esters were degraded at the same rate, zeaxanthin esters responded differently to the oxidation process, and were degraded more quickly than free zeaxanthin. The presence of unsaturated fatty acids (mainly linoleic) that esterify zeaxanthin help to accelerate the degradation of this xanthophyll and decreasing its antioxidant action. The antioxidant capacity of capsorubin and capsanthin (both in free and esterified form) exclusive to the genus capsicum should be taken into account.  相似文献   

7.
The complete sequence of orange homologous capsanthin/capsorubin synthase gene is 3788 bp long with a coding sequence of 1512 bp, which encodes a polypeptide of 503 amino acids. The 5' upstream sequence is 1721 bp long and the 3' downstream sequence is 555 bp long. The amino acid sequence of this gene is 78% and 69% identical to the genes from carrot and pepper, respectively. It is also partially homologous to plant neoxanthin synthase, lycopene beta-cyclase and lycopene epsilon cyclase genes. Isolation of the gene provides a framework for elucidation of the mechanisms involved in inability of citrus to produce capsanthin and capsorubin.  相似文献   

8.
The biosynthetic pathway of cyclic carotenoid is known to be quantitatively and qualitatively different in the non-green plastids of Capsicum annuum fruits compared with chloroplasts. Here, the cloning is described of a novel cDNA from this organism, which encodes an enzyme catalyzing the cyclization of lycopene to β-carotene when expressed in Escherichia coli . The corresponding gene is constitutively expressed during fruit development. Significant amino acid sequence identity was observed between this enzyme and capsanthin/capsorubin synthase which is involved in the synthesis of the species-specific red carotenoids of C. annuum fruits. The latter enzyme was found also to possess a lycopene β-cyclase activity when expressed in E. coli . A model is proposed for the origin of the capsanthin/capsorubin synthase gene and the role of this enzyme, together with the newly cloned lycopene cyclase, in the specific re-channeling of linear carotenoids into β-cyclic carotenoids in C. annuum ripening fruits.  相似文献   

9.
The author investigated the presence of various carotenoids in Ascidiella aspersa (O. F. Müller), (Tunicata) by means of columnar and thin-layer chromatography.The investigations revealed the presence of the following carotenoids: cynthiaxanthin (2.9%), capsanthin (32.6%), capsorubin (4.8%), capsorubin-like (15.2%), astaxanthin (4.7%) and astacene (39.8%).  相似文献   

10.
Fully green and mature red fruits of the Yolo Wonder A variety of Capsicum annuum were analysed for their carotenoid content. The disappearance of chlorophyll was followed by an increased synthesis of carotenoids. Lutein was not detected in the red fruit in which capsanthin was the main carotenoid. It appeared as diester, monoester and free forms, while capsorubin occured as a diester only. Cryptocapsin was not esterified.  相似文献   

11.
The spindle-shaped chromoplasts of the ripe fruit of Asparagusofficinalis developed from chloroplasts that lost grana andstroma lamellae and accumulated large-sized plastoglobules,most of which transformed into fibrils of exceptionally largediameter. The carotenoid concentration was high in ripe fruits(2520 µg g–1 fresh wt) and consisted mainly of capsanthin,ß-carotene and zeazanthin. A. officinalis is onlythe third species reported to contain both capsanthin and capsorubin. The large diameter of both fibrils and their associated plastoglobulesenabled verification that flbrils pass through plastoglobules.Unlike most fibrillar chromoplasts, the plastoglobules remainedassociated with flbrils even in fully-ripe fruit, and a straightline relationship can be established between plastoglobule andfibril diameter. The presence of more than one fibril developingfrom a plastoglobule, and the occasional existence of fibrilstwisted helically around one another, is interpreted to meanthat fibril growth by lateral addition of microfibrils is unlikely. The microfibrillar ultrastructure of Asparagus flbrils was differentto that found for Capsicum fibrils, and these differences areillustrated in two models. These differences, however, do notnecessarily mean that the fibrils of each species are constructedof different protein sub-units, although the bonding betweensub-units is different.  相似文献   

12.
13.
A chromoplast preparation from Capsicum annuum fruit catalyses the conversion of antheraxanthin into capsanthin (the main carotenoid of this fruit). The reaction is not affected by ATP, NADP or NADPH. The optimal pH is in the broad range 7–8. The role played by epoxy-xanthophylls in the biogenesis of Capsicum ketocarotenoids is enhanced by the ability of the chromoplast to carry out the epoxidation of zeaxanthin.  相似文献   

14.
A geranylgeranyl pyrophosphate synthase (GGPPS) gene from Capsicum annuum (bell pepper) was cloned. The nucleotide sequence shows that this gene, like the capsanthin/capsorubin gene but unlike the phytoene synthase gene from C. annuum, is not interrupted by an intron. Southern blot analysis of C. annuum genomic DNA suggests the presence of a single gene highly similar to the cDNA and also of additional related sequences. The present data suggest that this cloned gene is functional.  相似文献   

15.
V. Tolman 《Amino acids》1996,11(1):15-36
Summary A survey of the synthetic pathways leading to the fluorine-containing analogues of amino acids is given. From the great number of syntheses the typical examples are selected and divided into two groups: classical syntheses and the modern ones. The classical ammonolysis of halogeno acids and equivalent reactions are discussed as first, followed by a few examples of oxo amino group transformation. Conversion of the oxo compounds into amino acids richer by one carbon atom is realized by the Strecker and hydantoin syntheses. For the prolongation by two carbons, the Erlenmeyer azlactone method and alkylation of CH-acidic esters are applied. The modern syntheses are represented by direct fluorination by elemental fluorine and other electrophilic fluorinating reagents. Further examples include the applications of the Yarovenko reagent, sulphur tetrafluoride and its derivative DAST. The use of trifluoropyruvates as the fluoro synthons is mentioned briefly. Finally, the examples of the amidocarboxylation method and the syntheses of diverse-fluorinated methionines are shown.  相似文献   

16.
A survey is given of the lycopene cyclase genes present in bacteria, fungi and plants where two completely unrelated types exist. One is the classical monomeric bacterial beta-cyclase gene, crtY, which may be an ancestor of crtL, the gene for a beta-cyclase in cyanobacteria. From crtL a line of evolution can be drawn to plant beta- and epsilon-cyclase genes and to the gene of capsanthin/capsorubin synthase. In Gram-positive bacteria two genes crtYc and crtYd are present. They encode two proteins which have to interact as a heterodimer for lycopene beta-cyclization. From this type of lycopene cyclase gene the fungal lycopene cyclase/phytoene synthase fusion gene evolved.  相似文献   

17.
Embryos of the silkworm, Bombyx mori L., were dispersed by trypsin and the dissociated cells were cultured for infection with nuclear polyhedrosis virus (NPV) of the silkworm. The monolayer and suspension cultures were infected with NPV. RNA and DNA syntheses in the normal and NPV-infected cells were measured by incorporation of 32P into RNA and DNA fractions. RNA and DNA syntheses in the cells after infection significantly increased over those in control cells (mock infection). The effects of actinomycin D, chloramphenicol and mitomycin C on RNA and DNA syntheses in infected cells were examined. The syntheses were inhibited by the antibiotics. It was suggested that the cellular DNA synthesis was inhibited by the viral infection, because the mitomycin C-resistant DNA synthesis was found in the normal cells but not in the infected cells treated with mitomycin C. The rate of DNA synthesis induced by NPV was immediately dropped to that of control cells by addition of chloramphenicol, while the RNA synthesis induced by NPV was not affected for 6 hr after the addition of chloramphenicol. If the antibiotic did not affect the size of precursor pools, this event suggested that the RNA polymerase concerned with viral RNA synthesis was more stable than the DNA polymerase participating in the viral DNA synthesis. The viral DNA as templates for RNA and DNA syntheses was decomposed by mitomycin C.  相似文献   

18.
Klavuzon is a naphthalen-1-yl substituted α,β-unsaturated δ-lactone derivative, and is one of the anti-proliferative members of this class of compounds. Asymmetric and racemic syntheses of novel α,β-unsaturated δ-lactone derivatives are important to investigate their potential for the treatment of cancer. In this study, asymmetric and racemic syntheses of heteroatom-substituted klavuzon derivatives are reported. The syntheses were completed by a well-known three-step procedure. Anti-proliferative activity of seven novel racemic klavuzon derivatives were reported against MCF-7, PC3, HCT116 p53+/+ and HCT116 p53−/− cancer cell lines. Topoisomerase I inhibitory properties of 5,6-dihydro-2H-pyran-2-one derivatives were also studied.  相似文献   

19.
β-Phenetyl alcohol and procaine hydrochloride are known to alter membrane structure. Their effects on the syntheses of tyramine oxidase and arylsulfatase were studied in Klebsiella aerogenes. β-Phenetyl alcohol inhibited the syntheses of membrane-bound tyramine oxidase and arylsulfatase, located in the periplasm, under non-repressing and derepressing conditions, but did not affect the syntheses of β-galactosidase and histidase, which are located internally. In contrast, procaine hydrochloride stimulated the synthesis of tyramine oxidase and derepressed the synthesis of arylsulfatase, but inhibited non-repressed synthesis of arylsulfatase. Thus, derepressed synthesis of cellular arylsulfatase was affected by the level of tyramine oxidase synthesis. Structural alterations in the cell membrane seem to impair the formation of active-arylsulfatase protein in the periplasmic space.  相似文献   

20.
This review focuses on the syntheses of PI3K/Akt/mTOR inhibitors that have been reported outside of the patent literature in the last 5 years but is largely centered on synthetic work reported in 2011 and 2012. While focused on syntheses of inhibitors, some information on in vitro and in vivo testing of compounds is also included. Many of these reported compounds are reversible, competitive adenosine triphosphate (ATP) binding inhibitors, so given the structural similarities of many of these compounds to the adenine core, this review presents recent work on inhibitors based on where the synthetic chemistry was started, that is, inhibitor syntheses which started with purines/pyrimidines are followed by inhibitor syntheses which began with pyridines, pyrazines, azoles, and triazines then moves to inhibitors which bear no structural resemblance to adenine: liphagal, wortmannin and quercetin analogs. The review then finishes with a short section on recent syntheses of phosphotidyl inositol (PI) analogs since competitive PI binding inhibitors represent an alternative to the competitive ATP binding inhibitors which have received the most attention.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号