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1.
Food Chem ; 296: 160-166, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202300

RESUMO

Vitamin E is a family of related compounds with different vitamin E activities and antioxidant properties that includes tocopherols, tocotrienols and plastochromanol-8. Plant oils could serve as an industrial source not only of tocopherols, but also tocotrienols and plastochromanol-8, which exhibit much stronger antioxidant activities than tocopherols. The aim of this study was a quantitative and qualitative analysis of vitamin E in certain plant oils. We demonstrated the presence of vitamin E derivatives in all the plant oils tested. The highest tocopherol contents were in pomegranate, wheat germ and raspberry seed oils. In general, γ-tocopherol was the predominant tocopherol homologue. Tocotrienols were also identified in most of the oils, but their content was much lower. The highest concentration of tocotrienols was in coriander seed oil. Plastochromanol-8 was present in most of the oils, but wheat germ oil was the richest source.


Assuntos
Óleos Vegetais/química , Vitamina E/análise , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Rubus/química , Rubus/metabolismo , Tocotrienóis/análise , gama-Tocoferol/análise
2.
J Plant Physiol ; 231: 415-433, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30412849

RESUMO

With unfavourable climate changes and an increasing global population, there is a great need for more productive and stress-tolerant crops. As traditional methods of crop improvement have probably reached their limits, a further increase in the productivity of crops is expected to be possible using genetic engineering. The number of potential genes and metabolic pathways, which when genetically modified could result in improved photosynthesis and biomass production, is multiple. Photosynthesis, as the only source of carbon required for the growth and development of plants, attracts much attention is this respect, especially the question concerning how to improve CO2 fixation and limit photorespiration. The most promising direction for increasing CO2 assimilation is implementating carbon concentrating mechanisms found in cyanobacteria and algae into crop plants, while hitherto performed experiments on improving the CO2 fixation versus oxygenation reaction catalyzed by Rubisco are less encouraging. On the other hand, introducing the C4 pathway into C3 plants is a very difficult challenge. Among other points of interest for increased biomass production is engineering of metabolic regulation, certain proteins, nucleic acids or phytohormones. In this respect, enhanced sucrose synthesis, assimilate translocation to sink organs and starch synthesis is crucial, as is genetic engineering of the phytohormone metabolism. As abiotic stress tolerance is one of the key factors determining crop productivity, extensive studies are being undertaken to develop transgenic plants characterized by elevated stress resistance. This can be accomplished due to elevated synthesis of antioxidants, osmoprotectants and protective proteins. Among other promising targets for the genetic engineering of plants with elevated stress resistance are transcription factors that play a key role in abiotic stress responses of plants. In this review, most of the approaches to improving the productivity of plants that are potentially promising and have already been undertaken are described. In addition to this, the limitations faced, potential challenges and possibilities regarding future research are discussed.


Assuntos
Produção Agrícola/métodos , Fotossíntese , Desenvolvimento Vegetal , Engenharia Genética , Fotossíntese/genética , Desenvolvimento Vegetal/genética , Fenômenos Fisiológicos Vegetais/genética , Plantas/genética , Plantas Geneticamente Modificadas , Estresse Fisiológico/genética
4.
Plant Physiol Biochem ; 122: 1-9, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29169080

RESUMO

The data presented indicate that there is a variety of unique prenyllipids, often of very limited taxonomic distribution, whose origin, biosynthesis, metabolism and biological function deserves to be elucidated. These compounds include tocoenols, tocochromanol esters, tocochromanol acids, plastoquinones and ubiquinones. Additionally, based on the available data, it can be assumed that there are still unrecognized prenyllipids, like prenylquinols fatty acid esters of the hydroquinone ring, including prenylquinol phosphates, and others, whose biological function might be of great importance. Our knowledge of these compounds is not only important from the scientific point of view, but may also be of practical significance to medicine, pharmacy or cosmetics.


Assuntos
Plantas/química , Plantas/metabolismo , Plastoquinona/química , Plastoquinona/metabolismo , Ubiquinona/química , Ubiquinona/metabolismo
5.
Oxid Med Cell Longev ; 2017: 5092754, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28642809

RESUMO

[This corrects the article DOI: 10.1155/2016/1920208.].

6.
Mini Rev Med Chem ; 17(12): 1039-1052, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27457214

RESUMO

OBJECTIVE: This review examines various aspects of vitamin E, both in plant metabolism and with regard to its importance for human health. Vitamin E is the collective name of a group of lipidsoluble compounds, chromanols, which are widely distributed in the plant kingdom. Their biosynthetic pathway, intracellular distribution and antioxidant function in plants are well recognized, although their other functions are also considered. CONCLUSION: Analytical methods for the determination of vitamin E are discussed in detail. Furthermore, the vitamin E metabolism and its antioxidant action in humans are described. Other nonantioxidant functions of vitamin E are also presented, such as its anti-inflammatory effects, role in the prevention of cardiovascular diseases and cancer, as well as its protective functions against neurodegenerative and other diseases.


Assuntos
Plantas/química , Vitamina E/biossíntese , Animais , Antioxidantes/análise , Antioxidantes/metabolismo , Antioxidantes/farmacocinética , Cromatografia Líquida de Alta Pressão , Humanos , Sistema Imunitário/metabolismo , Doenças Neurodegenerativas/tratamento farmacológico , Plantas/metabolismo , Tocoferóis/análise , Tocoferóis/química , Tocoferóis/metabolismo , Tocoferóis/farmacocinética , Tocotrienóis/análise , Tocotrienóis/química , Tocotrienóis/metabolismo , Tocotrienóis/farmacocinética , Vitamina E/análise , Vitamina E/farmacocinética , Vitamina E/uso terapêutico
7.
PLoS One ; 11(7): e0159629, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27462710

RESUMO

In the present studies, we focused on substrate specificity of tocopherol cyclase, the key enzyme in the biosynthesis of the tocopherols and plastochromanol-8, the main plant lipid antioxidants, with special emphasis on the preference for tocopherols and plastochromanol-8 precursors, taking advantage of the recombinant enzyme originating from Arabidopsis thaliana and isolated plastoglobules, thylakoids and various model systems like micelles and thylakoids. Plastoglobules and triacylglycerol micelles were the most efficient reaction environment for the cyclase. In various investigated systems, synthesis of γ-tocopherol proceeded considerably faster than that of plastochromanol-8, probably mainly due to different localization of the corresponding substrates in the analyzed lipid structures. Moreover, our study was complemented by bioinformatics analysis of the phylogenetic relations of the cyclases and sequence motifs, crucial for the enzyme activity, were proposed. The analysis revealed also a group of tocopherol cyclase-like proteins in a number of heterotrophic bacterial species, with a conserved region common with photosynthetic organisms, that might be engaged in the catalytic activity of both groups of organisms.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Transferases Intramoleculares/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Cromanos/metabolismo , Transferases Intramoleculares/química , Transferases Intramoleculares/genética , Filogenia , Especificidade por Substrato , Tilacoides/metabolismo , Tocoferóis/metabolismo , Vitamina E/análogos & derivados , Vitamina E/metabolismo
8.
Physiol Plant ; 157(2): 147-60, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27174597

RESUMO

In this study, 25 accessions of Arabidopsis thaliana originating from a variety of climate conditions were grown under controlled circumstances of different light intensity and temperature. The accessions were analyzed for prenyllipids content and composition, as well as expression of the genes involved in tocochromanol biosynthesis (vte1-5). It was found that the applied conditions did not strongly affect total tocochromanols content and there was no apparent correlation of the tocochromanol content with the origin of the accessions. However, the presented results indicate that the temperature, more than the light intensity, affects the expression of the vte1-5 genes and the content of some prenyllipids. An interesting observation was that under low growth temperature, the hydroxy-plastochromanol (PC-OH) to plastochromanol (PC) ratio was considerably increased regardless of the light intensity in most of the accessions. PC-OH is known to be formed as a result of singlet oxygen stress, therefore this observation indicates that the singlet oxygen production is enhanced under low temperature. Unexpectedly, the highest increase in the PC-OH/PC ratio was found for accessions originating from cold climate (Shigu, Krazo-1 and Lov-5), even though such plants could be expected to be more resistant to low temperature stress.


Assuntos
Antioxidantes/metabolismo , Arabidopsis/fisiologia , Cromanos/metabolismo , Regulação da Expressão Gênica de Plantas , Antioxidantes/análise , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis , Cromanos/análise , Temperatura Baixa , Geografia , Luz , Lipídeos/biossíntese , Lipídeos/química , Prenilação , Oxigênio Singlete/metabolismo , Temperatura
9.
Environ Pollut ; 213: 957-965, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27060280

RESUMO

In the present study we analyze the effect of seed treatment by a range of nano-TiO2 concentrations on the growth of Arabidopsis thaliana plants, on the vitamin E content and the expression of its biosynthetic genes, as well as activity of antioxidant enzymes and lipid peroxidation. To conduct the mechanistic analysis of nano-TiO2 on plants growth and antioxidant status we applied nanoparticles concentrations that are much higher than those reported in the environment. We find that as the concentration of nano-TiO2 increases, the biomass, and chlorophyll content in 5-week-old Arabidopsis thaliana plants decrease in a concentration dependent manner. In opposite, higher nano-TiO2 concentration enhanced root growth. Our results indicate that a high concentration of nano-TiO2 induces symptoms of toxicity and elevates the antioxidant level. We also find that the expression levels of tocopherol biosynthetic genes were either down- or upregulated in response to nano-TiO2. Thermoluminescence analysis shows that higher nano-TiO2 concentrations cause lipid peroxidation. To the best of our knowledge, this is the first report concerning the effect of nano-TiO2 on vitamin E status in plants. We conclude that nano-TiO2 affects the antioxidant response in Arabidopsis thaliana plants. This could be an effect of a changes in vitamin E gene expression that is diminished under lower tested nano-TiO2 concentrations and elevated under 1000 µg/ml.


Assuntos
Antioxidantes/metabolismo , Arabidopsis/efeitos dos fármacos , Poluentes Ambientais/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Nanopartículas , Titânio/farmacologia , Vitamina E/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Biomassa , Clorofila/metabolismo , Relação Dose-Resposta a Droga , Poluentes Ambientais/análise , Poluentes Ambientais/toxicidade , Genes de Plantas , Nanopartículas/toxicidade , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Sementes/efeitos dos fármacos , Sementes/metabolismo , Titânio/análise , Titânio/toxicidade , Vitamina E/biossíntese , Vitamina E/genética
10.
N Biotechnol ; 33(5 Pt B): 636-643, 2016 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-26970272

RESUMO

Isoprenoid quinones and chromanols in plants fulfill both signaling and antioxidant functions under oxidative stress. The redox state of the plastoquinol pool (PQ-pool), which is modulated by interaction with reactive oxygen species (ROS) during oxidative stress, has a major regulatory function in both short- and long-term acclimatory responses. By contrast, the scavenging of ROS by prenyllipids affects signaling pathways where ROS play a role as signaling molecules. As the primary antioxidants, isoprenoid quinones and chromanols are synthesized under high-light stress in response to any increased production of ROS. During photo-oxidative stress, these prenyllipids are continuously synthesized and oxidized to other compounds. In turn, their oxidation products (hydroxy-plastochromanol, plastoquinol-C, plastoquinone-B) can still have an antioxidant function. The oxidation products of isoprenoid quinones and chromanols formed specifically in the face of singlet oxygen, can be indicators of singlet oxygen stress.


Assuntos
Cromanos/metabolismo , Plantas/metabolismo , Terpenos/metabolismo , Antioxidantes/metabolismo , Biotecnologia , Oxirredução , Estresse Oxidativo , Plastoquinona/metabolismo , Quinonas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Tocoferóis/metabolismo
12.
Postepy Biochem ; 61(1): 102-13, 2015.
Artigo em Polonês | MEDLINE | ID: mdl-26281359

RESUMO

Arabidopsis thaliana since a few decades is used as a model for biological and plant genetic research. Natural variation of this species is related to its geographical range which covers different climate zones and habitats. The ability to occupy such a wide area by Arabidopsis is possible due to its stress tolerance and adaptability. Arabidopsis accessions exhibit phenotypic and genotypic variation, which is a result of adaptation to local environmental conditions. During development, plants are subjected to various stress factors. Plants show a spectrum of reactions, processes and phenomena that determine their survival in these adverse conditions. The response of plants to stress involves signal detection and transmission. These reactions are different and depend on the stressor, its intensity, plant species and life strategy. It is assumed that the populations of the same species from different geographical regions acclimated to the stress conditions develop a set of alleles, which allow them to grow and reproduce. Therefore, the study of natural variation in response to abiotic stress among Arabidopsis thaliana accessions allows to find key genes or alleles, and thus the mechanisms by which plants cope with adverse physical and chemical conditions. This paper presents an overview of recent findings, tools and research directions used in the study of natural variation in Arabidopsis thaliana accessions. Additionally, we explain why accessions can be used in the phylogenetic analyses and to study demography and migration of Arabidopsis thaliana.


Assuntos
Aclimatação/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/classificação , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Variação Genética , Filogenia , Dispersão Vegetal/fisiologia , Especificidade da Espécie
13.
Plant Cell Environ ; 38(12): 2698-706, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26013323

RESUMO

In the present study, we have identified new prenyllipid metabolites formed during high light stress in Arabidopsis thaliana, whose origin and function remained unknown so far. It was found that plastoquinone-C accumulates mainly in the reduced form under high light conditions, as well as during short-term excess light illumination both in the wild-type and tocopherol biosynthetic vte1 mutant, suggesting that plastoquinone-C, a singlet oxygen-derived prenyllipid, is reduced in chloroplasts by photosystem II or enzymatically, outside thylakoids. Plastoquinone-B, a fatty acid ester of plastoquinone-C, was identified for the first time in Arabidopsis in high light grown wild-type plants and during short-time, excess light illumination of the wild-type plants and the vte1 mutant. The gene expression analysis showed that vte2 gene is most pronouncedly up-regulated among the prenyllipid biosynthetic genes under high light and induction of its expression is mainly caused by an increased level of singlet oxygen, as was demonstrated in experiments with D2 O-treated plants under excess light conditions.


Assuntos
Alquil e Aril Transferases/genética , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos da radiação , Transferases Intramoleculares/genética , Plastoquinona/metabolismo , Oxigênio Singlete/metabolismo , Alquil e Aril Transferases/metabolismo , Arabidopsis/química , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Transferases Intramoleculares/metabolismo , Luz , Mutação , Estresse Oxidativo , Complexo de Proteína do Fotossistema II/metabolismo , Plastoquinona/análise , Tilacoides/metabolismo , Tocoferóis/metabolismo
14.
Physiol Plant ; 154(2): 194-209, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25214438

RESUMO

During their lifetime, plants need to adapt to a changing environment, including light and temperature. To understand how these factors influence plant growth, we investigated the physiological and antioxidant responses of two Arabidopsis accessions, Shahdara (Sha) from the Shahdara valley (Tajikistan, Central Asia) in a mountainous area and Lovvik-5 (Lov-5) from northern Sweden to different light and temperature conditions. These accessions originate from different latitudes and have different life strategies, both of which are known to be influenced by light and temperature. We showed that both accessions grew better in high-light and at a lower temperature (16°C) than in low light and at 23°C. Interestingly, Sha had a lower chlorophyll content but more efficient non-photochemical quenching than Lov-5. Sha, also showed a higher expression of vitamin E biosynthetic genes. We did not observe any difference in the antioxidant prenyllipid level under these conditions. Our results suggest that the mechanisms that keep the plastoquinone (PQ)-pool in more oxidized state could play a role in the adaptation of these accessions to their local climatic conditions.


Assuntos
Antioxidantes/metabolismo , Arabidopsis/fisiologia , Aclimatação , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Arabidopsis/ultraestrutura , Clorofila/metabolismo , Luz , Oxirredução , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Folhas de Planta/ultraestrutura , Plastoquinona/metabolismo , Suécia , Temperatura
15.
Phytochemistry ; 108: 9-16, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25308762

RESUMO

Plastochromanol-8 (PC-8) is an antioxidant that, together with tocopherols and tocotrienols, belongs to the group of tocochromanols. Plastochromanol-8 has been found to occur in several plant species, including mosses, and lichens. PC-8 is found in seeds, leaves and other organs of higher plants. In leaves, PC-8 is restricted to chloroplasts. The identification of tocopherol cyclase (VTE1) as the key enzyme in the biosynthesis of PC-8 suggests that plastoglobules are the primary site of its biosynthesis. Other enzymes related with PC-8 biosynthesis in plastoglobules include: NDC1 and the ABC1-like kinase ABC1K3. The antioxidant properties of PC-8 are similar to those of other chloroplastic antioxidants in polar solvents but considerably they are enhanced in hydrophobic environments, suggesting that the unsaturated side chain performs some quenching activity. As a result of a non-enzymatic reaction, singlet oxygen can oxidize any of the 8 double bonds in the side chain of PC-8, giving at least eight hydroxy-PC-8 isomers. This review summarizes current evidence of a widespread distribution of PC-8 in photosynthetic organisms, as well as the contribution of PC-8 to the pool of lipid-soluble antioxidants in both leaves and seeds.


Assuntos
Cromanos/química , Vitamina E/análogos & derivados , Antioxidantes/química , Antioxidantes/metabolismo , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Cromanos/metabolismo , Hevea/química , Transferases Intramoleculares/metabolismo , Estrutura Molecular , NADH NADPH Oxirredutases/metabolismo , Folhas de Planta/química , Sementes/química , Vitamina E/química , Vitamina E/metabolismo
16.
Plant Cell Environ ; 37(2): 392-401, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23848570

RESUMO

In the present study, singlet oxygen (¹O2) scavenging activity of tocopherol and plastochromanol was examined in tocopherol cyclase-deficient mutant (vte1) of Arabidopsis thaliana lacking both tocopherol and plastochromanol. It is demonstrated here that suppression of tocopherol and plastochromanol synthesis in chloroplasts isolated from vte1 Arabidopsis plants enhanced ¹O2 formation under high light illumination as monitored by electron paramagnetic resonance spin-trapping spectroscopy. The exposure of vte1 Arabidopsis plants to high light resulted in the formation of secondary lipid peroxidation product malondialdehyde as determined by high-pressure liquid chromatography. Furthermore, it is shown here that the imaging of ultra-weak photon emission known to reflect oxidation of lipids was unambiguously higher in vte1 Arabidopsis plants. Our results indicate that tocopherol and plastochromanol act as efficient ¹O2 scavengers and protect effectively lipids against photooxidative damage in Arabidopsis plants.


Assuntos
Arabidopsis/metabolismo , Depuradores de Radicais Livres/metabolismo , Estresse Oxidativo , Oxigênio Singlete/metabolismo , Tocoferóis/metabolismo , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Cloroplastos/metabolismo , Cromatografia Líquida de Alta Pressão , Transferases Intramoleculares/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Detecção de Spin
17.
Plant Cell Environ ; 37(6): 1464-73, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24329808

RESUMO

In the present study, we have shown that hydroxy-plastochromanol and plastoquinone-C, the hydroxy derivatives of plastochromanol and plastoquinone-9, respectively, are specifically formed from the parent compounds upon action of singlet oxygen and can be regarded as stable, specific, natural products of singlet oxygen action during photo-oxidative stress in vivo. The presented data indicate that plastoquinone-C formation dominates mainly during relatively short periods of high light stress where efficient production of singlet oxygen takes place, whereas hydroxy-plastochromanol is rather formed under conditions of long-term, less pronounced generation of singlet oxygen. An interesting observation was that hydroxy-plastochromanol is formed even at very low light conditions (5-10 µmol photons m(-2) s(-1)), indicating that singlet oxygen is generated not only during high light stress but also its formation by photosystem II is inseparably connected with the functioning of this photosystem even at the lowest light intensities.


Assuntos
Arabidopsis/efeitos da radiação , Cromanos/metabolismo , Estresse Oxidativo , Plastoquinona/metabolismo , Antioxidantes/metabolismo , Arabidopsis/metabolismo , Cromanos/química , Cromatografia Líquida de Alta Pressão , Lipídeos/química , Plastoquinona/análogos & derivados , Plastoquinona/química
18.
Biochim Biophys Acta ; 1817(5): 705-10, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22365927

RESUMO

The redox state of plastoquinone-pool in chloroplasts is crucial for driving many responses to variable environment, from short-term effects to those at the gene expression level. In the present studies, we showed for the first time that the plastoquinone-pool undergoes relatively fast oxidation during high light stress of low light-grown Arabidopsis plants. This oxidation was not caused by photoinhibition of photosystem II, but mainly by singlet oxygen generated in photosystem II and non-photochemical quenching in light harvesting complex antenna of the photosystem, as revealed in experiments with a singlet oxygen scavenger and with Arabidopsis npq4 mutant. The latter mechanism suppresses the influx of electrons to the plastoquinone-pool preventing its excessive reduction. The obtained results are of crucial importance in light of the function of the redox state of the plastoquinone-pool in triggering many high light-stimulated physiological responses of plants.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Luz , Processos Fotoquímicos/efeitos da radiação , Plastoquinona/metabolismo , Oxigênio Singlete/metabolismo , Estresse Fisiológico/efeitos da radiação , Clorofila/metabolismo , Compostos de Epóxi/metabolismo , Oxirredução/efeitos da radiação , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Teoria Quântica
20.
J Plant Physiol ; 168(17): 2021-7, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-21856038

RESUMO

In the present study, we isolated novel tocochromanols from green leaves of Kalanchoe daigremontiana and primary leaves of etiolated seedlings of Phaseolus coccineus that were identified as ß-, γ-, and δ-tocomonoenols with unsaturation at the terminal isoprene unit of the side chain. The content of γ-tocomonoenol in leaves of etiolated bean increased gradually with the age of seedlings, reaching 50% of the γ-tocopherol level in 40-day-old plants. The content of this compound in leaves was increased by short illumination of etiolated plants and by addition of homogentisic acid, a biosynthetic precursor of tocopherols. These data indicated that γ-tocomonoenol is synthesized de novo from homogentisic acid and tetrahydro-geranylgeraniol diphosphate, a phytol precursor. Based on these results, a biosynthetic pathway of tocomonoenols is proposed.


Assuntos
Kalanchoe/química , Phaseolus/química , Vitamina E/metabolismo , Vias Biossintéticas , Cromatografia Líquida de Alta Pressão , Ácido Homogentísico/metabolismo , Kalanchoe/metabolismo , Kalanchoe/efeitos da radiação , Luz , Espectrometria de Massas , Phaseolus/metabolismo , Phaseolus/efeitos da radiação , Folhas de Planta/química , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Plântula/química , Plântula/metabolismo , Plântula/efeitos da radiação , Fatores de Tempo , Vitamina E/química , Vitamina E/isolamento & purificação
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