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1.
Int J Mol Sci ; 21(18)2020 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-32906784

RESUMEN

The root bark of Morus has long been appreciated as an antiphlogistic, diuretic and expectorant drug in Chinese herbal medicine, albeit with barely known targets and mechanisms of action. In the 1970s, the development of analytic chemistry allowed for the discovery of morusin as one of 7 different isoprene flavonoid derivatives in the root bark of Morus. However, the remarkable antioxidant capacity of morusin with the unexpected potential for health benefits over the other flavonoid derivatives has recently sparked scientific interest in the biochemical identification of target proteins and signaling pathways and further clinical relevance. In this review, we discuss recent advances in the understanding of the functional roles of morusin in multiple biological processes such as inflammation, apoptosis, metabolism and autophagy. We also highlight recent in vivo and in vitro evidence on the clinical potential of morusin treatment for multiple human pathologies including inflammatory diseases, neurological disorders, diabetes, cancer and the underlying mechanisms.


Asunto(s)
Flavonoides/metabolismo , Flavonoides/farmacología , Morus/metabolismo , Antioxidantes/farmacología , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Butadienos/química , Flavonoides/química , Hemiterpenos/química , Humanos , Inflamación/tratamiento farmacológico , Corteza de la Planta/metabolismo , Extractos Vegetales/farmacología , Raíces de Plantas/metabolismo , Transducción de Señal/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos
2.
Molecules ; 25(18)2020 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-32933154

RESUMEN

Kuromoji (Lindera umbellata) is a tree that grows throughout Japan. The components of kuromoji essential oil have antitumor and aromatherapy effects. However, the composition of the hydrosol, obtained as a by-product of the essential oil process, is unknown. Furthermore, it is unknown whether kuromoji essential oil has a deodorizing effect. Therefore, the purpose of the current study was to compare the chemical composition of kuromoji essential oil and hydrosol, as well as evaluate the deodorizing effect of the former. The chemical composition of samples was evaluated using gas chromatography-mass spectrometry (GC-MS). Additionally, the deodorizing effect of Kuromoji essential oil was investigated with the detector tube method using ammonia, hydrogen sulfide, methyl mercaptan, and isovaleric acid. Linalool was the most abundant component in both the essential oil and hydrosol; however, its proportion was higher in the hydrosol (57.5%) than in the essential oil (42.8%). The hydrosol contained fewer chemical components, but higher proportions of trans-geraniol and ethanol. Moreover, the essential oil eliminated 50% of ammonia and 97.6% or more of isovaleric acid. Interestingly, linalool was soluble in the hydrosol and did not irritate the skin. This suggests that the hydrosol may be an effective foot care product.


Asunto(s)
Monoterpenos Acíclicos/aislamiento & purificación , Desodorantes/aislamiento & purificación , Lindera/química , Aceites Volátiles/química , Aceites de Plantas/química , Monoterpenos Acíclicos/química , Monoterpenos Acíclicos/farmacología , Amoníaco/química , Desodorantes/farmacología , Etanol/química , Cromatografía de Gases y Espectrometría de Masas , Hemiterpenos/química , Sulfuro de Hidrógeno/química , Japón , Aceites Volátiles/farmacología , Ácidos Pentanoicos/química , Aceites de Plantas/farmacología , Compuestos de Sulfhidrilo/química
3.
Molecules ; 24(19)2019 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-31547628

RESUMEN

In citrus color mutants, the levels of carotenoid constituents and other secondary metabolites are different in their corresponding wild types. Terpenoids are closely related to coloration, bitterness, and flavor. In this study, terpenoid profiles and hormones in citrus fruits of two red-flesh mutants-Red Anliu orange and Red-flesh Guanxi pummelo-and their corresponding wild types were investigated using GC/MS, HPLC, and LC-MS/MS. Results showed that Red Anliu orange (high in carotenoids) and Anliu orange (low in carotenoids) accumulated low levels of limonoid aglycones but high levels of monoterpenoids; conversely, Red-flesh Guanxi pummelo (high in carotenoids) and Guanxi pummelo (deficient in carotenoids) accumulated high levels of limonoid aglycones but low levels of monoterpenoids. However, isopentenyl diphosphate was present at similar levels. A correlation analysis indicated that jasmonic and salicylic acids might play important roles in regulating terpenoid biosynthesis. Additionally, the similarities of carotenoid and volatile profiles between each mutant and its corresponding wild type were greater than those between the two mutants or the two wild types. The flux balance of terpenoid metabolism in citrus fruit tends toward stability among various citrus genera that have different terpenoid profiles. Bud mutations could influence metabolite profiles of citrus fruit to a limited extent.


Asunto(s)
Citrus/química , Frutas/química , Odorantes/análisis , Terpenos/química , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Cromatografía de Gases y Espectrometría de Masas , Hemiterpenos/química , Monoterpenos/química , Compuestos Organofosforados/química , Extractos Vegetales/química , Espectrometría de Masas en Tándem
4.
Org Biomol Chem ; 16(22): 4195-4198, 2018 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-29796533

RESUMEN

Two new 6-norpolycyclic polyprenylated acylphloroglucinols (PPAPs), hypermonins A (1) and B (2), featuring an undescribed decahydroindeno[1,7-bc]furan ring system, were isolated from the leaves and twigs of Hypericum monogynum. These compounds are a pair of epimers with opposite configurations at the C-5 position. Their structures, including their absolute configurations, were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway of 1 and 2 was also proposed. Compound 1 exhibited a significant protective effect against corticosterone-induced injury in PC12 cells.


Asunto(s)
Hemiterpenos/farmacología , Compuestos Heterocíclicos con 3 Anillos/farmacología , Hypericum/química , Fármacos Neuroprotectores/farmacología , Floroglucinol/análogos & derivados , Floroglucinol/farmacología , Animales , Línea Celular Tumoral , Hemiterpenos/química , Hemiterpenos/aislamiento & purificación , Compuestos Heterocíclicos con 3 Anillos/química , Compuestos Heterocíclicos con 3 Anillos/aislamiento & purificación , Modelos Químicos , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/aislamiento & purificación , Floroglucinol/química , Floroglucinol/aislamiento & purificación , Hojas de la Planta/química , Ratas , Estereoisomerismo
5.
Phytochemistry ; 138: 128-133, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28262248

RESUMEN

Five previously undescribed hemiterpene glycosides, cibotiumbarosides E-I, and two known hemiterpene glucosides, were isolated from the rhizome of Cibotium barometz (L.) J. Sm. The structures of cibotiumbarosides E-I were established by 1D and 2D NMR spectroscopic analyses and HRMS. The absolute configuration of the aglycone of cibotiumbaroside E was assigned by calculated ECD with the TDDFT method. Cibotiumbarosides F and I both exhibited remarkable hepatoprotective activity against APAP-induced acute liver damage in vitro, which were more effective than the positive control, bicyclol. On the other hand, seven hemiterpene glycosides were all inactive in assays of cytotoxicity, neuroprotection, antidiabetes and anti-inflammation.


Asunto(s)
Glicósidos/química , Hemiterpenos/química , Rizoma/química , Tracheophyta/química , Glicósidos/aislamiento & purificación , Hemiterpenos/aislamiento & purificación , Células Hep G2 , Humanos , Estructura Molecular , Extractos Vegetales/química
6.
Fitoterapia ; 115: 128-134, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27751884

RESUMEN

Four new polyisoprenylated benzoylphloroglucinol derivatives, hyperscabrones J-M (1-4), were isolated from the air-dried aerial parts of Hypericum scabrum. Their structures were elucidated by spectroscopic methods and were subsequently confirmed by comparing with data of known compounds. The absolute configuration of the bicyclo[3.3.1]nonane-2,4,9-trione core was defined by the experimental and calculated electronic circular dichroism (ECD) spectra. The evaluation of their hepatoprotective activities against paracetamol-induced HepG2 cell damage showed that compounds 2 and 4 exhibited significant hepatoprotection at 10µM.


Asunto(s)
Hypericum/química , Floroglucinol/química , Sustancias Protectoras/química , Acetaminofén , Hemiterpenos/química , Hemiterpenos/aislamiento & purificación , Células Hep G2/efectos de los fármacos , Compuestos Heterocíclicos con 3 Anillos/química , Compuestos Heterocíclicos con 3 Anillos/aislamiento & purificación , Humanos , Estructura Molecular , Floroglucinol/análogos & derivados , Floroglucinol/aislamiento & purificación , Componentes Aéreos de las Plantas/química , Sustancias Protectoras/aislamiento & purificación
7.
ChemSusChem ; 9(24): 3434-3440, 2016 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-27885809

RESUMEN

Toluene is a basic chemical that is currently produced from petroleum resources. In this paper, we report a new route for the effective synthesis of toluene from isoprene and acrolein, two reactants readily available from biomass, through a simple two-step reaction. The process includes Diels-Alder cycloaddition of isoprene and acrolein in a Zn-containing ionic liquid at room temperature to produce methylcyclohex-3-enecarbaldehydes (MCHCAs) as intermediates, followed by M (M=Pt, Pd, Rh)/Al2 O3 -catalyzed consecutive dehydrogenation-decarbonylation of the MCHCAs at 573 K to generate toluene with an overall yield up to 90.7 %. Model reactions indicated that a synergistic inductive effect of the C=C double bond and the aldehyde group in MCHCA plays a key role in initiating the consecutive dehydrogenation-decarbonylation, and that methyl benzaldehydes are the key intermediates in the gas-phase transformation of MCHCAs. Microcalorimetric adsorption of CO on different catalysts showed that decarbonylation of the substrate occurs more likely on the strong adsorption sites. To the best of our knowledge, it is the first report of Pt/Al2 O3 -catalyzed consecutive dehydrogenation-decarbonylation of a given compound in one reactor. This work provides a highly efficient and environmental friendly route to toluene by utilizing two compounds that can be prepared from biomass.


Asunto(s)
Acroleína/química , Biomasa , Butadienos/química , Hemiterpenos/química , Pentanos/química , Tolueno/química , Adsorción , Óxido de Aluminio/química , Catálisis , Tecnología Química Verde , Platino (Metal)/química
8.
Phytochemistry ; 121: 30-7, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26542239

RESUMEN

Extracts from the stem and roots of the Bangladeshi medicinal plant Pothos scandens L. (Araceae) were isolated, and three hemiterpene glucoside aromatic esters, pothobanosides A (1), B (2), and C (3), and a phenylisobutanoid, pothobanol (4), along with 14 known compounds, were characterized. The isolates were tested for their estrogenic/anti-estrogenic activity using the estrogen-responsive human breast cancer cell lines MCF-7 and T47D, and syringoyl derivatives (2, 3, and canthoside B) showed strong inhibitory activity against both cell lines. Their less oxygenated analogs (1, and markhamioside F) were almost inactive. The isolates were also evaluated for hyaluronidase and histamine release inhibitory activities, and pothobanoside A (1) showed significant hyaluronidase inhibitory activity among the isolated compounds, which was similar to that of the positive control rosmarinic acid. Because hyaluronidase produces an angiogenic response that has been implicated in tumor invasiveness and metastasis, 1 could be valuable as an anti-tumor compound with a different mechanism of action from related compounds (2, 3). Pothobanoside C (3) and pothobanol (4) were also found to inhibit histamine release to a similar degree to the positive control epigallocatechin 3-O-(3"-O-methyl)-gallate. The histamine release inhibitory potency of these isolates may support the traditional uses of this plant in folk medicine.


Asunto(s)
Araceae/química , Butanos/aislamiento & purificación , Butanos/farmacología , Antagonistas de Estrógenos/aislamiento & purificación , Antagonistas de Estrógenos/farmacología , Glicósidos/aislamiento & purificación , Glicósidos/farmacología , Hemiterpenos/aislamiento & purificación , Hemiterpenos/farmacología , Fenoles/aislamiento & purificación , Fenoles/farmacología , Plantas Medicinales/química , Bangladesh , Butanos/química , Antagonistas de Estrógenos/química , Femenino , Glucósidos , Glicósidos/química , Hemiterpenos/química , Liberación de Histamina/efectos de los fármacos , Humanos , Hialuronoglucosaminidasa/antagonistas & inhibidores , Estructura Molecular , Fenoles/química
9.
Nat Prod Res ; 29(2): 180-4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25342202

RESUMEN

As a continuation of our ongoing studies aimed to reveal the presence of oxyprenylated anthraquinones in plants claimed to have a laxative effect, in this article, we describe the extraction and HPLC separation of madagascin (3-isopentenyloxyemodin) and 3-geranyloxyemodine from dried leaves and fruits of Senna alexandrina Mill. (Leguminosae) and leaves and gel of Aloe vera (L.) Burm. F. (Xanthorrhoeaceae). Both compounds are described herein for the first time as components of extracts of the title plants.


Asunto(s)
Aloe/química , Antraquinonas/química , Hemiterpenos/química , Senna/química , Antraquinonas/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Frutas/química , Hemiterpenos/aislamiento & purificación , Estructura Molecular , Extractos Vegetales/química , Hojas de la Planta/química
10.
Drug Dev Ind Pharm ; 40(2): 211-21, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23327358

RESUMEN

OBJECTIVE: To design and evaluate a novel pressure sensitive adhesive (PSA) patch containing traditional Chinese medicine (TCM) using styrene-isoprene-styrene (SIS) copolymer. METHOD: A mixture D-optimal design with ternary response surface diagram was employed in the optimization process. The proportions of SIS copolymer, tackifying resin and plasticizer were selected as the independent variables while tack force, peel strength of the patch and skin penetrability of methyl salicylate were selected as the dependent variables. The optimized patch was then evaluated including in vivo absorption, pharmacological activities and skin irritation, by comparing with a commercial patch based on natural rubber. RESULTS: The optimized patch, which comprised 30.0% SIS copolymer, 26.6% tackifying resin and 43.4% plasticizer, was superior to commercial patch in skin permeation, pharmacological activities and skin biocompatibility. CONCLUSION: SIS copolymer was a suitable substitute to natural rubber in producing patches containing TCM formula.


Asunto(s)
Butadienos/química , Diseño de Fármacos , Medicamentos Herbarios Chinos/química , Elastómeros/química , Hemiterpenos/química , Pentanos/química , Estireno/química , Parche Transdérmico , Animales , Butadienos/administración & dosificación , Evaluación Preclínica de Medicamentos/métodos , Medicamentos Herbarios Chinos/administración & dosificación , Elastómeros/administración & dosificación , Cobayas , Hemiterpenos/administración & dosificación , Masculino , Medicina Tradicional China/métodos , Ratones , Ratones Pelados , Técnicas de Cultivo de Órganos , Pentanos/administración & dosificación , Ratas , Ratas Wistar , Absorción Cutánea/efectos de los fármacos , Absorción Cutánea/fisiología , Estireno/administración & dosificación
11.
Phytother Res ; 28(1): 49-54, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23447335

RESUMEN

DNA methylation plays a pivotal role in the epigenetic regulation of the transcription of a number of cancer-related genes, thereby representing an important target for cancer prevention and treatment. In our search for DNA methyltransferase (DNMT) inhibitors from Formosan plants, by screening against a library consisting of 12 structurally distinct natural products, we identified kazinol Q {4-[6-(1,1-dimethyl-allyl)-7-hydroxy-chroman-2-yl]-3,6-bis-(3-methyl-but-2-enyl)-benzene-1,2-diol} as an inhibitor of recombinant DNMT1 with IC50 of 7 µM. The effect of kazinol Q on DNMT inhibition was validated by its ability to reactivate the expression of a DNA methylation-silenced gene, E-cadherin, in MDA-MB-231 breast cancer cells. Moreover, kazinol Q suppressed the proliferation of MCF-7 breast and LNCaP prostate cancer cells, in part, through apoptosis induction. The role of DNMT1 inhibition in mediating kazinol Q's antiproliferative effect was supported by the protective effect of ectopic expression of DNMT1 on kazinol Q-induced cell death. Molecular modeling analysis suggests that kazinol Q inhibited DNMT activity by competing with cytosine binding, a mechanism similar to that described for (-)-epigallocatechin-3-gallate (EGCG). Relative to EGCG, kazinol Q exhibits several desirable features for drug development, including chemical stability and increased hydrophobicity, and might have therapeutic relevance to cancer treatment.


Asunto(s)
ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , Metilación de ADN/efectos de los fármacos , Flavonoides/farmacología , Hemiterpenos/farmacología , Antígenos CD , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/patología , Cadherinas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , ADN (Citosina-5-)-Metiltransferasa 1 , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Femenino , Flavonoides/química , Hemiterpenos/química , Humanos , Concentración 50 Inhibidora , Masculino , Simulación del Acoplamiento Molecular , Neoplasias de la Próstata/patología , Especies Reactivas de Oxígeno/metabolismo , Taiwán
12.
Dalton Trans ; 42(25): 9033-9, 2013 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-23571673

RESUMEN

The synthesis and structural characterisation of the uranium(IV) amido-borohydrides (N'')2U{κ(2)-N(SiMe3)SiMe2CH2BBN-H} and U{κ(2)-N(SiMe3)SiMe2CH2BBN-H}2, and their activity as pre-catalysts for the polymerisation of isoprene are described.


Asunto(s)
Amidas/química , Borohidruros/química , Butadienos/química , Hemiterpenos/química , Hemiterpenos/síntesis química , Látex/síntesis química , Compuestos Organometálicos/química , Pentanos/química , Uranio/química , Catálisis , Látex/química , Modelos Moleculares , Estructura Molecular , Compuestos Organometálicos/síntesis química , Polimerizacion
13.
Curr Drug Targets ; 14(9): 959-63, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23469875

RESUMEN

Several natural compounds containing an anthraquinone core linked to a prenyloxy chain have been reported in the literature in recent years. The discovery in the plant kingdom of such secondary metabolites is a novel acquisition in the phytochemistry research field and in many cases led to a re-consideration of the secondary metabolite pool of well known anthraquinone-containing plants. In this review article we will focus on the phytochemistry and pharmacognosy of prenyloxyanthraquinones putting in evidence the natural sources and their biological properties as anti-microbial and anticancer agents.


Asunto(s)
Antraquinonas/química , Antraquinonas/farmacología , Hemiterpenos/química , Hemiterpenos/farmacología , Monoterpenos/química , Monoterpenos/farmacología , Fitoquímicos/química , Fitoquímicos/farmacología , Antraquinonas/aislamiento & purificación , Antraquinonas/uso terapéutico , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antineoplásicos/química , Antineoplásicos/farmacología , Hemiterpenos/aislamiento & purificación , Hemiterpenos/uso terapéutico , Humanos , Estructura Molecular , Monoterpenos/uso terapéutico , Farmacognosia , Fitoquímicos/uso terapéutico , Fitoterapia , Plantas/química , Metabolismo Secundario
14.
Fitoterapia ; 86: 1-5, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23376411

RESUMEN

Four new hemiterpenoid derivatives, taxilluside A-D (1-4), were isolated from the branches and leaves of Taxillus chinensis (DC.) Danser. Their structures were determined on the basis of spectroscopic analysis. Of these compounds, compounds 3 and 4 showed inhibition activity on Calcium concentration in myocardial cells evaluated by measuring the changes of fluorescence signal using Laser scanning confocal microscope.


Asunto(s)
Calcio/metabolismo , Hemiterpenos/aislamiento & purificación , Loranthaceae/química , Miocardio/metabolismo , Extractos Vegetales/farmacología , Animales , Hemiterpenos/química , Hemiterpenos/farmacología , Ratones , Estructura Molecular , Miocardio/citología , Miocitos Cardíacos/metabolismo , Extractos Vegetales/química , Hojas de la Planta , Tallos de la Planta
15.
Planta Med ; 79(3-4): 281-7, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23322560

RESUMEN

Ten new nervogenic acid derivatives (1-4, 6-11) and one known compound (5) have been isolated from Liparis nervosa. Their structures were determined using extensive spectroscopic analysis, including 1D and 2D NMR experiments. Compounds 3, 4, 9, 10, and 11 were evaluated for their cytotoxicity against A549, H460, Hela, MCF-7, Caco2, and HepG2 human cancer cell lines.


Asunto(s)
Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Orchidaceae/química , Células CACO-2/efectos de los fármacos , Línea Celular Tumoral , Disacáridos/química , Ensayos de Selección de Medicamentos Antitumorales , Células HeLa/efectos de los fármacos , Hemiterpenos/química , Humanos , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Estructura Molecular , Parabenos/química
16.
J Dent ; 41 Suppl 3: e53-61, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23103847

RESUMEN

OBJECTIVES: This study was to compare the effect of three different one-step polishing systems on the color stability of three different types of nanocomposites after immersion in coffee for one day and seven days and determine which nanocomposite material has the best color stability following polishing with each of the one-step polishing system. METHODS: The nanocomposites tested were Tetric EvoCeram, Grandio and Herculite Précis. A total of 120 discs (40/nanocomposite, 8mm×2mm) were fabricated. Ten specimens for each nanocomposite cured under Mylar strips served as the control. The other specimens were polished with OptraPol, OneGloss and Occlubrush immersed in coffee (Nescafé) up to seven days. Color measurements were made with a spectrophotometer at baseline and after one and seven days. Two way repeated measure ANOVA, two way ANOVA and Bonferroni tests were used for statistical analyses (P<0.05). RESULTS: The immersion time was a significant factor in the discoloration of the nanocomposites. The effect of three one-step polishing systems on the color stability was also significant. The color change values of the materials cured against Mylar strips were the greatest. The lowest mean color change values were from the Occlubrush polished groups. The effect of the three different types of nanocomposite on the color change was significant. The highest color change values were with Tetric EvoCeram groups. The lowest color change values were with Herculite Précis groups. CONCLUSION: The color change of nanocomposite resins is affected by the type of composite, polishing procedure and the period of immersion in the staining agent.


Asunto(s)
Resinas Compuestas/química , Materiales Dentales/química , Pulido Dental/métodos , Nanocompuestos/química , Óxido de Aluminio/química , Bisfenol A Glicidil Metacrilato/química , Compuestos Inorgánicos de Carbono/química , Café , Color , Pulido Dental/instrumentación , Hemiterpenos/química , Humanos , Inmersión , Látex/química , Ensayo de Materiales , Polietilenglicoles/química , Polimerizacion , Ácidos Polimetacrílicos/química , Polivinilos/química , Compuestos de Silicona/química , Dióxido de Silicio/química , Siloxanos/química , Espectrofotometría/instrumentación , Propiedades de Superficie , Factores de Tiempo , Titanio/química
17.
Phytochemistry ; 71(8-9): 918-22, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20303132

RESUMEN

Deoxy-xylulose phosphate synthase (DXS) catalyzes the first step of the methylerythritol phosphate (MEP) pathway and it might regulate the metabolic flux in plastidic isoprenoid biosynthesis. We developed a sensitive assay suitable for plant extracts that is based on the decarboxylation of labeled pyruvate (1-(13)C)-PYR and detection of (13)CO(2) by isotope ratio mass spectrometry. We tested our method investigating the DXS activity in poplar leaves. Apparent DXS activity showed Michaelis constants of 111 and 158 microM for glyceraldehyde phosphate and pyruvate, respectively; pH and temperature optima were found at pH 8.6 and 45 degrees C. DXS activity was inhibited when the competitive inhibitor beta-fluoropyruvate was added to the reaction mixture. DXS activity strongly depended on leaf development with higher activity in young leaves and correlated fairly well with leaf isoprene emission potential. In mature poplar leaves, isoprene emission is the main metabolic sink of plastidic isoprenoid intermediates. Consequently, we found lower DXS activity in non-isoprene-emitting lines of poplar than in emitting plants as indicator of a lower demand of metabolic flux within the MEP pathway.


Asunto(s)
Butadienos/química , Hemiterpenos/química , Espectrometría de Masas/métodos , Pentanos/química , Populus/enzimología , Transferasas/metabolismo , Butadienos/metabolismo , Eritritol/análogos & derivados , Eritritol/metabolismo , Hemiterpenos/metabolismo , Isótopos/análisis , Estructura Molecular , Pentanos/metabolismo , Extractos Vegetales/química , Hojas de la Planta/enzimología , Hojas de la Planta/metabolismo , Populus/metabolismo , Fosfatos de Azúcar/metabolismo , Transferasas/análisis
18.
ACS Appl Mater Interfaces ; 1(10): 2390-9, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20355877

RESUMEN

Renewable composites were prepared by melt blending of polylactide and soybean oil. The blend morphology was tuned by the addition of poly(isoprene-b-lactide) block copolymers. Due to the extreme difference in the viscosities of soybean oil and polylactide, a critical block copolymer composition was found to induce a phase inversion point at which the minor soybean oil phase became the matrix surrounding polylactide particles. This transition was due to the thermodynamic interactions between the block copolymer and the two phases and shear forces acting on the mixture during blending. The size of the soybean oil droplets in the polylactide matrix was also highly dependent on the block copolymer composition. In binary polylactide/soybean oil blends, there was a limiting concentration of soybean oil that could be incorporated into the polylactide matrix (6% of the total blend weight), which could be increased up to 20% by the addition of block copolymers.


Asunto(s)
Butadienos/química , Hemiterpenos/química , Pentanos/química , Transición de Fase , Poliésteres/química , Aceite de Soja/química , Termodinámica
19.
Oper Dent ; 33(4): 413-20, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18666499

RESUMEN

OBJECTIVE: This study compared the color changes of five novel resin composites polished with two one-step polishing systems when exposed to coffee solution. METHODS: The resin composites tested were Filtek Supreme XT, Grandio, CeramX, Premise and Tetric EvoCeram. A total of 150 discs (30/resin composites, 10 x 2 mm) were fabricated. Ten specimens/resin composites cured under Mylar strips served as the control. The other samples were polished with PoGo and OptraPol discs for 30 seconds using a slow speed handpiece and immersed in coffee (Nescafé) for seven days. Color measurements were made with Vita Easyshade at baseline and after one and seven days. Repeated Measures ANOVA and Bonferroni tests were used for statistical analyses (p< or =0.05). RESULTS: The differences between the mean DeltaE* values for the resin composites polished with two different one-step systems were statistically significant (p<0.05). After one week, all materials exhibited significant color changes compared to baseline. All Mylar finished specimens showed the most intense staining (p<0.05). There were no significant differences between the OptraPol and PoGo polished groups. Mylar-finished specimens of CeramX, Tetric EvoCeram, Premise and Filtek Supreme XT presented the greatest staining (p<0.05). For Grandio, there were no significant differences between the Mylar and PoGo groups, while the most stain resistant surfaces were attained with OptraPol. CONCLUSION: Removing the outermost resin layer by polishing procedures is essential to achieving a stain resistant, more esthetically stable surface. One-step polishing systems can be used successfully for polishing nanocomposites.


Asunto(s)
Resinas Compuestas/química , Materiales Dentales/química , Pulido Dental/métodos , Nanocompuestos/química , Óxido de Aluminio/química , Bebidas , Compuestos Inorgánicos de Carbono/química , Café , Color , Pulido Dental/instrumentación , Diamante/química , Compuestos Férricos/química , Hemiterpenos/química , Humanos , Látex/química , Ensayo de Materiales , Metacrilatos/química , Poliuretanos/química , Compuestos de Silicona/química , Dióxido de Silicio/química , Propiedades de Superficie , Factores de Tiempo , Titanio/química
20.
Dent Mater J ; 27(6): 755-64, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19241682

RESUMEN

The purpose of this study was to investigate the influence of one-step polishing systems on the surface roughness of different flowable composites and a microhybrid composite. A total of 120 disks were fabricated and divided into six groups according to the different composite restorative materials tested (n = 20). Each group was further divided into four subgroups according to the polishing system (n = 5). For the control group, samples were left undisturbed after removal of Mylar strip. For the other three subgroups, samples were polished with PoGo, OptraPol, or Sof-Lex disks. Surface roughness was determined using a profilometer and observed under scanning electron microscope (SEM). Data were analyzed by one-way ANOVA and Duncan's multiple range test. For Tetric Flow, Grandio Flow, Filtek Supreme XT Flow, and Admira Flow, their lowest surface roughness values were obtained in Mylar Strip and PoGo groups. For Compoglass Flow, there were no significant differences between Mylar Strip, PoGo, and OptraPol. For Filtek Z250, the lowest surface roughness value was obtained with Mylar Strip. In light of the surface roughness results obtained, one-step polishing systems seemed to be a good choice for polishing flowable composites.


Asunto(s)
Resinas Compuestas/química , Materiales Dentales/química , Pulido Dental/métodos , Óxido de Aluminio/química , Compuestos Inorgánicos de Carbono/química , Cementos Dentales/química , Pulido Dental/instrumentación , Restauración Dental Permanente , Diamante/química , Compuestos Férricos/química , Hemiterpenos/química , Humanos , Látex/química , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Tereftalatos Polietilenos/química , Poliuretanos/química , Compuestos de Silicona/química , Dióxido de Silicio/química , Propiedades de Superficie , Titanio/química , Viscosidad
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