RESUMEN

Systemic treatment options for soft tissue sarcomas (STSs) have remained unchanged despite the need for novel drug candidates to improve STS outcomes. Drug repurposing involves the application of clinical drugs to different diseases, reducing development time, and cost. It has also become a fast and effective way to identify drug candidates. The present study used a computational method to screen three drug­gene interaction databases for novel drug candidates for the treatment of several common STS histologic subtypes through drug repurposing. STS survival­associated genes were generated by conducting a univariate cox regression analysis using The Cancer Genome Atlas survival data. These genes were then applied to three databases (the Connectivity Map, the Drug Gene Interaction Database and the L1000 Fireworks Display) to identify drug candidates for STS treatment. Additionally, pathway analysis and molecular docking were conducted to evaluate the molecular mechanisms of the candidate drug. Bepridil was identified as a potential candidate for several STS histologic subtype treatments by overlapping the screening results from three drug­gene interaction databases. The pathway analysis with the Kyoto Encyclopedia of Genes and Genomes predicted that Bepridil may target CRK, fibroblast growth factor receptor 4 (FGFR4), laminin subunit ß1 (LAMB1), phosphoinositide­3­kinase regulatory subunit 2 (PIK3R2), WNT5A, cluster of differentiation 47 (CD47), elastase, neutrophil expressed (ELANE), 15­hydroxyprostaglandin dehydrogenase (HPGD) and protein kinase cß (PRKCB) to suppress STS development. Further molecular docking simulation suggested a relatively stable binding selectivity between Bepridil and eight proteins (CRK, FGFR4, LAMB1, PIK3R2, CD47, ELANE, HPGD, and PRKCB). In conclusion, a computational method was used to identify Bepridil as a potential candidate for the treatment of several common STS histologic subtypes. Experimental validation of these in silico results is necessary before clinical translation can occur.

Asunto(s)

Antineoplásicos/farmacología , Bepridil/farmacología , Reposicionamiento de Medicamentos/métodos , Redes Reguladoras de Genes/genética , Sarcoma/tratamiento farmacológico , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Bepridil/química , Bepridil/uso terapéutico , Biología Computacional , Bases de Datos Genéticas/estadística & datos numéricos , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Redes Reguladoras de Genes/efectos de los fármacos , Humanos , Simulación del Acoplamiento Molecular , Unión Proteica , Sarcoma/genética , Sarcoma/mortalidad , Sarcoma/patología , Análisis de Supervivencia

RESUMEN

Docking on the p53-binding site of murine double minute 2 (MDM2) by small molecules restores p53's tumor-suppressor function. We previously assessed 3244 FDA-approved drugs via "computational conformer selection" for inhibiting MDM2 and p53 interaction. Here, we developed a surface plasmon resonance method to experimentally confirm the inhibitory effects of the known MDM2 inhibitor, nutlin-3a, and two drug candidates predicted by our computational method. This p53/MDM2 interaction displayed a dosage-dependent weakening when MDM2 is pre-mixed with drug candidates. The inhibition efficiency order is nutlin-3a (IC50 = 97 nM) > bepridil (206 nM) > azelastine (307 nM). Furthermore, we verified their anti-proliferation effects on SJSA-1 (wild-type p53 and overexpressed MDM2), SW480 (mutated p53), and SaOs-2 (deleted p53) cancer cell lines. The inhibitory order towards SJSA-1 cell line is nutlin-3a (IC50 = 0.8 µM) > bepridil (23 µM) > azelastine (25 µM). Our experimental results are in line with the computational prediction, and the higher IC50 values from the cell-based assays are due to the requirement of higher drug concentrations to penetrate cell membranes. The anti-proliferation effects of bepridil and azelastine on the cell lines with mutated and deleted p53 implied some p53-independent anti-proliferation effects.

Asunto(s)

Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Resonancia por Plasmón de Superficie , Proteína p53 Supresora de Tumor/metabolismo , Bepridil/química , Bepridil/metabolismo , Línea Celular Tumoral , Humanos , Imidazoles/química , Imidazoles/metabolismo , Piperazinas/química , Piperazinas/metabolismo , Unión Proteica , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-mdm2/genética , Bibliotecas de Moléculas Pequeñas/metabolismo , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/genética

RESUMEN

Calcium sensitizers enhance the transduction of the Ca(2+) signal into force within the heart and have found use in treating heart failure. However the mechanisms of action for most Ca(2+) sensitizers remain unclear. To address this issue an efficient fluorescence based approach to Ca(2+) sensitizer screening was developed which monitors cardiac troponin C's (cTnC's) hydrophobic cleft. This approach was tested on four common Ca(2+) -sensitizers, EMD 57033, levosimendan, bepridil and pimobendan with the aim of elucidating the mechanisms of action for each as well as proving the efficacy of the new screening method. Ca(2+) -titration experiments were employed to determine the effect on Ca(2+) sensitivity and cooperativity of cTnC opening, while stopped flow experiments were used to investigate the impact on cTnC relaxation kinetics. Bepridil was shown to increase the sensitivity of cTnC for Ca(2+) under all reconstitution conditions, sensitization by the other drugs was context dependent. Levosimendan and pimobendan reduced the rate of cTnC closing consistent with a stabilization of cTnC's open conformation while bepridil increased the rate of relaxation. Experiments were also run on samples containing cTnT(T204E), a known Ca(2+) -desensitizing phosphorylation mimic. Levosimendan, bepridil, and pimobendan were found to elevate the Ca(2+) -sensitivity of cTnT(T204E) containing samples in this context.

Asunto(s)

Calcio/metabolismo , Cardiotónicos/metabolismo , Miocardio/metabolismo , Troponina/metabolismo , Animales , Bepridil/química , Bepridil/metabolismo , Cardiotónicos/química , Hidrazonas/química , Hidrazonas/metabolismo , Cinética , Mutagénesis Sitio-Dirigida , Fosforilación , Unión Proteica , Piridazinas/química , Piridazinas/metabolismo , Ratas , Simendán , Espectrometría de Fluorescencia , Troponina/química , Troponina/genética

RESUMEN

The integrity of the p53 tumor suppressor pathway is compromised in the majority of cancers. In 7% of cancers p53 is inactivated by abnormally high levels of MDM2--an E3 ubiquitin ligase that polyubiquitinates p53, marking it for degradation. MDM2 engages p53 through its hydrophobic cleft, and blockage of that cleft by small molecules can re-establish p53 activity. Small molecule MDM2 inhibitors have been developed, but there is likely to be a high cost and long time period before effective drugs reach the market. An alternative is to repurpose FDA-approved drugs. This report describes a new approach, called Computational Conformer Selection, to screen for compounds that potentially inhibit MDM2. This screen was used to computationally generate up to 600 conformers of 3244 FDA-approved drugs. Drug conformer similarities to 41 computationally-generated conformers of MDM2 inhibitor nutlin 3a were ranked by shape and charge distribution. Quantification of similarities by Tanimoto combo scoring resulted in scores that ranged from 0.142 to 0.802. In silico docking of drugs to MDM2 was used to calculate binding energies and to visualize contacts between the top-ranking drugs and the MDM2 hydrophobic cleft. We present 15 FDA-approved drugs predicted to inhibit p53/MDM2 interaction.

Asunto(s)

Diseño Asistido por Computadora , Diseño de Fármacos , Imidazoles/química , Imidazoles/farmacología , Piperazinas/química , Piperazinas/farmacología , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Bepridil/química , Bepridil/farmacología , Aprobación de Drogas , Humanos , Conformación Molecular , Simulación del Acoplamiento Molecular , Proteínas Proto-Oncogénicas c-mdm2/química , Estados Unidos , United States Food and Drug Administration

RESUMEN

Cardiac troponin C (cTnC) is the Ca²âº dependent switch for contraction in heart muscle making it a potential target for drug research in the therapy of heart failure. Calcium binding on Troponin C (TnC) triggers a series of conformational changes exposing a hydrophobic pocket in the N-domain of TnC (cNTnC), which leads to force generation. Mutations and acidic pH have been related to altering the sensitivity of TnC affecting the efficiency of the heart. Bepridil, identified as a calcium sensitizer to TnC, has been experimentally found to bind to the N-domain pocket of TnC but with negative cooperativity. Screening and de novo design were carried out using LUDI and AUTOLUDI programs in this work to identify and design potential ligands that can bind to the hydrophobic pocket of TnC. Two docking centers and multiple searching radii including 5 Å, 5.5 Å, 6 Å, 6.5 Å, 7.0 Å and 7.5 Å were used in LUDI to screen the ZINC database. Based on the LUDI docking results, 8 molecules were identified from the database with good potential to bind into the binding pocket and they were used as template molecules to generate a series of new molecules by AUTOLUDI design. Out of all the newly-designed molecules, 14 new ligands were recognized to be potential ligands that can bind and fit well into the binding pocket. These molecules can be used as starting molecules to develop TnC ligands. The binding stability and binding affinity of these molecules to the protein was further analyzed by molecular dynamics simulations. The results show that the binding energies, interactions and complex stabilities of 6 ligands are comparable to or better than bepridil.

Asunto(s)

Troponina C/química , Bepridil/química , Sitios de Unión , Calcio/metabolismo , Concentración de Iones de Hidrógeno , Modelos Moleculares , Simulación de Dinámica Molecular , Miocardio/química , Miocardio/metabolismo , Conformación Proteica , Troponina C/metabolismo

RESUMEN

The two proteases beta-secretase and gamma-secretase generate the amyloid beta peptide and are drug targets for Alzheimer's disease. Here we tested the possibility of targeting the cellular environment of beta-secretase cleavage instead of the beta-secretase enzyme itself. beta-Secretase has an acidic pH optimum and cleaves the amyloid precursor protein in the acidic endosomes. We identified two drugs, bepridil and amiodarone, that are weak bases and are in clinical use as calcium antagonists. Independently of their calcium-blocking activity, both compounds mildly raised the membrane-proximal, endosomal pH and inhibited beta-secretase cleavage at therapeutically achievable concentrations in cultured cells, in primary neurons, and in vivo in guinea pigs. This shows that an alkalinization of the cellular environment could be a novel therapeutic strategy to inhibit beta-secretase. Surprisingly, bepridil and amiodarone also modulated gamma-secretase cleavage independently of endosomal alkalinization. Thus, both compounds act as dual modulators that simultaneously target beta- and gamma-secretase through distinct molecular mechanisms. In addition to Alzheimer's disease, compounds with dual properties may also be useful for drug development targeting other membrane proteins.

Asunto(s)

Amiodarona/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Bepridil/farmacología , Inhibidores Enzimáticos/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/enzimología , Amiodarona/química , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/sangre , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Bepridil/química , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Encéfalo/metabolismo , Línea Celular , Células Cultivadas , Inhibidores Enzimáticos/química , Femenino , Cobayas , Humanos , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Ratones , Ratones Transgénicos , Neuronas/efectos de los fármacos , Neuronas/enzimología , Neuronas/metabolismo , Nexinas de Proteasas , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo

RESUMEN

Anthrax lethal toxin is one of the fundamental components believed to be responsible for the virulence of Bacillus anthracis. In order to find novel compounds with anti-lethal toxin properties, we used a cell-based assay to screen a collection of approximately 500 small molecules. Nineteen compounds that blocked lethal toxin-mediated killing of RAW 264.7 macrophages were identified, and we report here on the characterization of the two most potent antitoxic compounds, amiodarone and bepridil. These drugs are used to treat cardiac arrhythmia or angina in humans at doses similar to those that provide protection against lethal toxin in vitro. Our results support a model whereby the antitoxic properties of both drugs result from their ability to block endosomal acidification, thereby blocking toxin entry. Amiodarone was tested in vivo and found to significantly increase survival of lethal toxin-challenged Fischer rats.

Asunto(s)

Amiodarona/farmacología , Carbunco/prevención & control , Toxinas Bacterianas/antagonistas & inhibidores , Bepridil/farmacología , Macrófagos Peritoneales/efectos de los fármacos , Amiodarona/química , Amiodarona/uso terapéutico , Animales , Antígenos Bacterianos , Bepridil/química , Bepridil/uso terapéutico , Células CHO , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cloroquina/farmacología , Cloroquina/uso terapéutico , Cricetinae , Cricetulus , AMP Cíclico/análisis , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Concentración de Iones de Hidrógeno , Concentración 50 Inhibidora , Macrófagos Peritoneales/microbiología , Masculino , Ratones , Estructura Molecular , Ratas , Ratas Endogámicas F344 , Factores de Tiempo

RESUMEN

Cardiac troponin C (cTnC) is the Ca(2+)-dependent switch for contraction in heart muscle and a potential target for drugs in the therapy of heart failure. Ca(2+) binding to the regulatory domain of cTnC (cNTnC) induces little structural change but sets the stage for cTnI binding. A large "closed" to "open" conformational transition occurs in the regulatory domain upon binding cTnI(147-163) or bepridil. This raises the question of whether cTnI(147-163) and bepridil compete for cNTnC.Ca(2+). In this work, we used two-dimensional (1)H,(15)N-heteronuclear single quantum coherence (HSQC) NMR spectroscopy to examine the binding of bepridil to cNTnC.Ca(2+) in the absence and presence of cTnI(147-163) and of cTnI(147-163) to cNTnC.Ca(2+) in the absence and presence of bepridil. The results show that bepridil and cTnI(147-163) bind cNTnC.Ca(2+) simultaneously but with negative cooperativity. The affinity of cTnI(147-163) for cNTnC.Ca(2+) is reduced approximately 3.5-fold by bepridil and vice versa. Using multinuclear and multidimensional NMR spectroscopy, we have determined the structure of the cNTnC.Ca(2+).cTnI(147-163).bepridil ternary complex. The structure reveals a binding site for cTnI(147-163) primarily located on the A/B interhelical interface and a binding site for bepridil in the hydrophobic pocket of cNTnC.Ca(2+). In the structure, the N terminus of the peptide clashes with part of the bepridil molecule, which explains the negative cooperativity between cTnI(147-163) and bepridil for cNTnC.Ca(2+). This structure provides insights into the features that are important for the design of cTnC-specific cardiotonic drugs, which may be used to modulate the Ca(2+) sensitivity of the myofilaments in heart muscle contraction.

Asunto(s)

Bepridil/química , Bloqueadores de los Canales de Calcio/química , Fragmentos de Péptidos/química , Troponina C/química , Troponina I/química , Citoesqueleto de Actina/efectos de los fármacos , Calcio/metabolismo , Cardiotónicos/farmacología , Diseño de Fármacos , Humanos , Espectroscopía de Resonancia Magnética

RESUMEN

The pro-oxidant activity of potent oxidants and foods was determined using the kinetic analysis of crocin bleaching. In its reduced form, crocin has an absorption band at 443 nm, which disappears upon oxidation by a generic radical species. Hydroxyl radicals generated by hydrogen peroxide, peroxyl radicals from ABAP, and the stable free radical DPPH(*) were allowed to react with crocin in an aqueous solution at 40 degrees C. Pro-oxidant activity was taken as the ratio between the decrease in crocin absorbance at 5 min and the relevant oxidant concentration. The test proposed was used to evaluate the pro-oxidant activity of widely consumed foods such as pasteurized skim milk and bread. They both exerted significant pro-oxidant activities, which were attributed to the early nonenzymatic browning products formed upon heat treatment.

Asunto(s)

Bepridil/análogos & derivados , Carotenoides/química , Alimentos , Oxidantes/química , Picratos , Amidinas/química , Animales , Bepridil/química , Compuestos de Bifenilo , Pan/análisis , Fenómenos Químicos , Química Física , Peróxido de Hidrógeno/química , Radical Hidroxilo/química , Cinética , Leche/química , Oxidación-Reducción , Peróxidos/química , Soluciones , Agua

RESUMEN

Pure thiosulfinates, R-S(O)S-R (2), where R = Me (2a), Pr (2b), or All (2c), at levels up to 4 mM were not capable of scavenging hydrogen peroxide or superoxide anion. Relative to standard antioxidants (ascorbic acid, n-propyl gallate, butylated hydroxytoluene, Trolox, and reduced glutathione), these thiosulfinates were 1-3 orders of magnitude less efficient at reducing 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 0.5-2 orders of magnitude less efficient at quenching singlet oxygen, and about equally effective at scavenging hydroxyl radical. Generally, AllS(O)SAll (2c) was the most effective and PrS(O)SPr (2b) was the least effective thiosulfinate in these assays, except that MeS(O)SMe (2a) exhibited no quenching effect toward singlet oxygen. These thiosulfinates were also incapable at levels up to 0.1 mM (where they were toxic) of in vitro induction of quinone reductase (QR) in murine hepatoma (hepa 1c1c7) cells. However, S-1-propenyl-L-cysteine sulfoxide (isoalliin, 1a) and cycloalliin (3) induced QR in this system at 2 mM and 1 mM, respectively, although doubling of QR required levels of 10-15 mM.

Asunto(s)

Allium/química , Antioxidantes/farmacología , Bepridil/análogos & derivados , Cisteína/análogos & derivados , Cisteína/farmacología , Picratos , Ácidos Sulfínicos/farmacología , Bepridil/química , Compuestos de Bifenilo , Inducción Enzimática/efectos de los fármacos , Depuradores de Radicales Libres , Radicales Libres , Peróxido de Hidrógeno/química , Radical Hidroxilo/química , NAD(P)H Deshidrogenasa (Quinona)/biosíntesis , Oxidación-Reducción , Oxígeno Singlete/química , Superóxidos/química

RESUMEN

Antioxidant activity of 24 ferulic acid related compounds together with 6 gallic acid related compounds was evaluated using several different physical systems as well as their radical scavenging activity. The radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) decreased in the order caffeic acid > sinapic acid > ferulic acid > ferulic acid esters > p-coumaric acid. In bulk methyl linoleate, test hydroxycinnamic acids and ferulic acid esters showed antioxidant activity in parallel with their radical scavenging activity. In an ethanol-buffer solution of linoleic acid, the activity of test compounds was not always associated with their radical scavenging activity. Ferulic acid was most effective among the tested phenolic acids. Esterification of ferulic acid resulted in increasing activity. The activity of alkyl ferulates was somewhat influenced by the chain length of alcohol moiety. When the inhibitory effects of alkyl ferulates against oxidation of liposome induced by AAPH were tested, hexyl, octyl, and 2-ethyl-1-hexyl ferulates were more active than the other alkyl ferulates. Furthermore, lauryl gallate is most effective among the tested alkyl gallates. These results indicated that not only the radical scavenging activity of antioxidants, but also their affinity with lipid substrates, might be important factors in their activity.

Asunto(s)

Antioxidantes/farmacología , Bepridil/análogos & derivados , Ácidos Cumáricos/farmacología , Picratos , Bepridil/química , Compuestos de Bifenilo , Tampones (Química) , Ácidos Cafeicos/farmacología , Esterificación , Etanol , Depuradores de Radicales Libres , Radicales Libres , Ácido Gálico/farmacología , Calor , Ácido Linoleico/química , Liposomas/química , Oryza/química , Estructuras de las Plantas/química , Soluciones

RESUMEN

Ellagic acid, a plant-derived polyphenol, inhibits gamma-radiation (hydroxyl radical) induced lipid peroxidation in rat liver microsomes in a dose- and concentration-dependent manner. Its antioxidant capacity has been estimated using the 1,1-diphenyl-2-picrylhydrazyl radical assay. To understand the actual mechanisms involved in antioxidant activity and the free radical scavenging ability,a nanosecond pulse radiolysis technique has been employed. The rate constants for the reactions of several reactive oxygen species and reactive nitrogen species such as hydroxyl, peroxyl, and nitrogen dioxide radicals have been found to be in the range of 10(6)-10(9) M(-1) s(-1). The ellagic acid radicals have been characterized by the absorption spectra and decay kinetics. Studies on the reactions of ellagic acid with the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical and the radicals of ellagic acid with ascorbate have been used to estimate its one-electron reduction potential. Ellagic acid has also been found to be a good scavenger of peroxynitrite. Using stopped-flow reaction analyzer with absorption detection, the rate constant for this reaction has been determined to be 3.7 x 10(3) M(-1) s (-1). The electron spin resonance spectra of the oxidized ellagic acid radicals have been recorded by horseradish peroxidase and hydrogen peroxide method.

Asunto(s)

Antioxidantes/farmacología , Bepridil/análogos & derivados , Ácido Elágico/farmacología , Picratos , Animales , Bepridil/química , Compuestos de Bifenilo , Fenómenos Químicos , Química Física , Espectroscopía de Resonancia por Spin del Electrón , Ácido Elágico/química , Depuradores de Radicales Libres , Radicales Libres , Rayos gamma , Radical Hidroxilo/metabolismo , Radical Hidroxilo/farmacología , Peroxidación de Lípido/efectos de los fármacos , Peroxidación de Lípido/efectos de la radiación , Masculino , Microsomas Hepáticos/metabolismo , Peróxidos , Ácido Peroxinitroso/química , Fenoles/química , Radiólisis de Impulso , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno , Espectrofotometría , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis

RESUMEN

This study was performed to investigate the free radical scavenging activity of Panax red ginseng C.A. Meyer aqueous extract on 1,1-dipheny-2-picrylhydrazyl (DPPH), carbon-centered radical, hydroxyl and superoxide radicals using Electron Spin Resonance (ESR) spectrometer and spin-trapping techniques. Two different Red ginseng aqueous extracts prepared by boiling water or room temperature extraction exhibited no significant difference in free radical scavenging activity. Ginseng extracts completely eliminated DPPH radical at 2 mg/ml. About 0.5 mg/ml ginseng extracts quenched 80% carbon-centered free radicals generated from 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). Hydroxyl radical and superoxide radical were generated by UV irradiation and trapped by 5,5-dimethyl-l-pyrroline-N oxide (DMPO). Ginseng extracts scavenged 40% of hydroxyl radical at 0.1 mg/ml. Two mg/ml ginseng extracts completely scavenged superoxide radical. Ginseng extracts did not scavenge nitric oxide. The ESR data demonstrate that red ginseng aqueous extract is not a strong free radical scavenger.

Asunto(s)

Bepridil/análogos & derivados , Depuradores de Radicales Libres/química , Panax/química , Picratos , Bepridil/química , Compuestos de Bifenilo , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/química , Radical Hidroxilo/química , Indicadores y Reactivos , Óxido Nítrico/química , Extractos Vegetales/química , Superóxidos/química

RESUMEN

The antioxidant activity of Lactuca scariola (Compositae) was investigated by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical. The methanolic extract of the aerial parts of Lactuca scariola showed strong radical scavenging activity. The EtOAc soluble fraction exhibited a stronger activity than the others, and was purified by silica gel and Sephadex LH-20 column chromatography. Quercetin-3-O-beta-D-glucopyranoside, luteolin-7-O-beta-D-glucopyranoside, luteolin, quercetin and kaempferol, together with 1beta,13-dihydrolactucin were isolated from the EtOAc soluble fraction as active ingredients.

Asunto(s)

Antioxidantes/química , Antioxidantes/farmacología , Asteraceae/química , Bepridil/análogos & derivados , Picratos , Antioxidantes/aislamiento & purificación , Bepridil/química , Compuestos de Bifenilo , Cromatografía Liquida , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/aislamiento & purificación , Depuradores de Radicales Libres/farmacología , Espectroscopía de Resonancia Magnética , Extractos Vegetales/análisis , Solventes , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta

RESUMEN

Radical scavenging properties of the extracts of some fruits and flowers, as well as of their complex formulations used as fruit teas, were tested on DPPH radical using electron spin resonance spectroscopy. The contents of anthocyanosides and flavonoids in plant materials were determined with spectrophotometric method. The most effective DPPH radical scavengers were extracts from Fructus Aroniae, Fructus Myrtilli and Fructus Rosae and the fruit teas, including them as main ingredients. No simple correlation was found between the scavenging activity and the content of anthocyanosides and flavonoids. The results can be rationalised by taking into account the presence of catechins and ascorbic acid.

Asunto(s)

Antocianinas/química , Antioxidantes/análisis , Bepridil/análogos & derivados , Flavonoides/química , Depuradores de Radicales Libres/química , Frutas/química , Picratos , Plantas Medicinales/química , Bepridil/química , Compuestos de Bifenilo , Espectroscopía de Resonancia por Spin del Electrón , Extractos Vegetales/química

RESUMEN

Five kinds of ear mushrooms are commercially available in Taiwan, including black, red, jin, snow, and silver ears. Methanolic extracts were prepared from these ear mushrooms, and their antioxidant properties were studied. For all methanolic extracts from ear mushrooms, the antioxidant activities in the 1,3-diethyl-2-thiobarbituric acid method were moderate (38.6 approximately 74.6%) at 1.0-5.0 mg/mL. Methanolic extracts from red, jin, and snow ears showed excellent antioxidant activities in the conjugated diene method at 5.0 mg/mL. At 5.0 mg/mL, reducing powers of methanolic extracts were in the descending order of snow > black approximately red approximately jin > silver ears. The scavenging effect of methanolic extracts from ear mushrooms on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent except for that from silver ears. Ear mushroom extracts were not good scavengers for hydroxyl free radicals but were good chelators for ferrous ions. Naturally occurring antioxidants, including ascorbic acid, tocopherols, and total phenols, were found in the methanolic extracts. However, beta-carotene was not detected. Total antioxidant components were 15.69, 30.09, 27.83, 49.17, and 31.70 mg/g for black, red, jin, snow, and silver ears, respectively.

Asunto(s)

Agaricales/química , Antioxidantes/química , Bepridil/análogos & derivados , Picratos , Bepridil/química , Compuestos de Bifenilo , Depuradores de Radicales Libres/química , Radical Hidroxilo/química , Metanol/química , Oxidación-Reducción

RESUMEN

One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.

Asunto(s)

Antioxidantes/análisis , Bepridil/análogos & derivados , Ácido Clorogénico/análogos & derivados , Picratos , Hojas de la Planta/química , Poaceae/química , Animales , Antioxidantes/química , Antioxidantes/farmacología , Bepridil/química , Compuestos de Bifenilo , Ácido Clorogénico/análisis , Ácido Clorogénico/farmacología , Inhibidores Enzimáticos/farmacología , Depuradores de Radicales Libres , Peroxidación de Lípido , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-Dawley , Superóxidos/química , Xantina Oxidasa/antagonistas & inhibidores

RESUMEN

Dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber (which is different from dioscorine found in tubers of Dioscorea hirsuta), was purified to homogeneity after DE-52 ion exchange column according to the methods of Hou et al. (J. Agric. Food Chem. 1999, 47, 2168-2172). A single band of 32 kDa dioscorin was obtained on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel with 2-mercaptoethanol treatment. This purified dioscorin was shown by spectrophotometric method to have scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in a pH-dependent manner. There is a positive correlation between scavenging effects against DPPH (8-46%) and amounts of 32 kDa dioscorin (5.97-47.80 nmol) added in Tris-HCl buffer (pH 7.9), which are comparable to those of glutathione at the same concentrations. Using electron paramagnetic resonance (EPR) spectrometry for DPPH radical detection, it was found that the intensities of the EPR signal were decreased by 28.6 and 57 nmol of 32 kDa dioscorin in Tris-HCl buffer (pH 7.9) more than in distilled water compared to controls. EPR spectrometry was also used for hydroxyl radical detection. It was found that 32 kDa dioscorin could capture hydroxyl radical, and the intensities of the EPR signal were significantly decreased dose-dependently by 1.79-14.32 nmol of 32 kDa dioscorin (r = 0.975) compared to the control. It is suggested that 32 kDa dioscorin, the storage protein of yam tuber, may play a role as antioxidant in tubers and may be beneficial for health when people take it as a food additive or consume yam tubers.

Asunto(s)

Antioxidantes/farmacología , Bepridil/análogos & derivados , Dioscorea/química , Picratos , Proteínas de Plantas/farmacología , Bepridil/química , Compuestos de Bifenilo , Espectroscopía de Resonancia por Spin del Electrón , Depuradores de Radicales Libres , Radicales Libres , Glutatión/farmacología , Concentración de Iones de Hidrógeno , Radical Hidroxilo/química , Proteínas de Plantas/aislamiento & purificación , Espectrofotometría

RESUMEN

The Maillard reaction occurs during many industrial and domestic thermal treatments of foods. It is widely used because of its role in creating colors, flavors, textures, and other functional properties in foodstuffs. Proteins glycated without the use of conventional chemical reagents have improved technofunctional properties such as heat stability, emulsifying, and foaming properties. The present study was carried out to determine the extent to which this reaction can convey antioxidant, antimicrobial, or cytotoxic activities to beta-lactoglobulin (BLG) and to its tryptic and peptic hydrolysates. BLG was modified with six different sugars in solution at 60 degrees C. Antiradical properties were estimated using a radical scavenging activity test. Antimicrobial activities against different bacterial strains were studied with a diffusion disk method. Cytotoxic tests were performed using two cell lines and the 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) rapid colorimetric assay. Glycation induced a radical scavenging activity to BLG, the intensity of which depended on the sugar used for modification. Proteins modified with ribose and arabinose showed the highest radical scavenging activities depicted by about 80 and 60% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorption decrease at 515 nm. No antimicrobial effect of any glycated form of BLG against Escherichia coli, Bacillus subtilis, Listeria innocua, and Streptococcus mutans was observed. The MTT test showed no enhancement of cytotoxicity by modified proteins and peptides against COS-7 and HL-60 cells. Thus, glycated proteins could be used in formulated food as functional ingredients with a radical scavenging activity able to delay deterioration due to oxidation. This use could be even more advisable considering the lack of toxicity to eukaryotic and prokaryotic cell cultures demonstrated in this work.

Asunto(s)

Bacterias/efectos de los fármacos , Bepridil/análogos & derivados , Muerte Celular/efectos de los fármacos , Depuradores de Radicales Libres , Lactoglobulinas/química , Lactoglobulinas/farmacología , Reacción de Maillard , Picratos , Animales , Bacterias/crecimiento & desarrollo , Bepridil/química , Compuestos de Bifenilo , Células COS/efectos de los fármacos , Glicosilación , Células HL-60/efectos de los fármacos , Calor , Humanos , Hidrólisis , Pepsina A/metabolismo , Relación Estructura-Actividad , Tripsina/metabolismo

RESUMEN

A reactive oxygen species has been implicated in a range of human pathological diseases such as atherosclerosis and certain cancers. Flavonoids are reported to exhibit various biological activities, including antioxidative and free radical scavenging activities. Several flavonoids obtained from barley leaves, soybean and some medicinal plants, Silybum marianum, Sophorae Flos, Cinnamon, Ephedrae Herba and Scutellariae Radix, were tested for their DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. The structure-activity relationships suggested that not only the numbers of hydroxy group but also the position of hydroxy group might be important for mediating potent activity.

Asunto(s)

Bepridil/análogos & derivados , Bepridil/química , Flavonoides/química , Depuradores de Radicales Libres/química , Picratos , Plantas Medicinales/química , Compuestos de Bifenilo , Colorimetría , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/química