The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Harold Corke - One of the best experts on this subject based on the ideXlab platform.
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sword bean canavalia gladiata as a source of antioxidant phenolics
International Journal of Food Science and Technology, 2016Co-Authors: Renyou Gan, Wingyee Lui, Harold CorkeAbstract:Summary Sword beans (Canavalia gladiata) have been used as grain legumes and medicinal plants in China for thousands of years. To explore new natural antioxidant sources, the antioxidant capacity and phenolic composition in the soluble and bound fractions of three sword bean genotypes were evaluated in vitro. The red and black sword beans were found to have antioxidant capacity compared to the white sword bean, and this was attributed to their red and black bean coats, which possessed extremely high phenolic content. Gallic Acid and its derivatives, such as methyl gallate, digalloyl hexoside and Digallic Acid, were the main phenolic compounds in the coats of red and black sword beans. Therefore, the red and black sword beans, especially their bean coats, are good sources of antioxidant phenolics and may have potential health benefits.
Alan S. Verkman - One of the best experts on this subject based on the ideXlab platform.
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tmem16a inhibitors reveal tmem16a as a minor component of calcium activated chloride channel conductance in airway and intestinal epithelial cells
Journal of Biological Chemistry, 2011Co-Authors: Wan Namkung, Puay Wah Phuan, Alan S. VerkmanAbstract:Abstract TMEM16A (ANO1) functions as a calcium-activated chloride channel (CaCC). We developed pharmacological tools to investigate the contribution of TMEM16A to CaCC conductance in human airway and intestinal epithelial cells. A screen of ∼110,000 compounds revealed four novel chemical classes of small molecule TMEM16A inhibitors that fully blocked TMEM16A chloride current with an IC50 < 10 μm, without interfering with calcium signaling. Following structure-activity analysis, the most potent inhibitor, an aminophenylthiazole (T16Ainh-A01), had an IC50 of ∼1 μm. Two distinct types of inhibitors were identified. Some compounds, such as tannic Acid and the arylaminothiophene CaCCinh-A01, fully inhibited CaCC current in human bronchial and intestinal cells. Other compounds, including T16Ainh-A01 and Digallic Acid, inhibited total CaCC current in these cells poorly, but blocked mainly an initial, agonist-stimulated transient chloride current. TMEM16A RNAi knockdown also inhibited mainly the transient chloride current. In contrast to the airway and intestinal cells, all TMEM16A inhibitors fully blocked CaCC current in salivary gland cells. We conclude that TMEM16A carries nearly all CaCC current in salivary gland epithelium, but is a minor contributor to total CaCC current in airway and intestinal epithelia. The small molecule inhibitors identified here permit pharmacological dissection of TMEM16A/CaCC function and are potential development candidates for drug therapy of hypertension, pain, diarrhea, and excessive mucus production.
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inhibition of ca2 activated cl channels by gallotannins as a possible molecular basis for health benefits of red wine and green tea
The FASEB Journal, 2010Co-Authors: Wan Namkung, Puay Wah Phuan, Jay R Thiagarajah, Alan S. VerkmanAbstract:TMEM16A was found recently to be a calcium-activated Cl− channel (CaCC). CaCCs perform important functions in cell physiology, including regulation of epithelial secretion, cardiac and neuronal excitability, and smooth muscle contraction. CaCC modulators are of potential utility for treatment of hypertension, diarrhea, and cystic fibrosis. Screening of drug and natural product collections identified tannic Acid as an inhibitor of TMEM16A, with IC50 ∼ 6 μM and ∼100% inhibition at higher concentrations. Tannic Acid inhibited CaCCs in multiple cell types but did not affect CFTR Cl− channels. Structure-activity analysis indicated the requirement of gallic or Digallic Acid substituents on a macromolecular scaffold (gallotannins), as are present in green tea and red wine. Other polyphenolic components of teas and wines, including epicatechin, catechin, and malvidin-3-glucoside, poorly inhibited CaCCs. Remarkably, a 1000-fold dilution of red wine and 100-fold dilution of green tea inhibited CaCCs by >50%. Tannic...
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Inhibition of Ca2+-activated Cl− channels by gallotannins as a possible molecular basis for health benefits of red wine and green tea
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2010Co-Authors: Wan Namkung, Puay Wah Phuan, Jay R Thiagarajah, Alan S. VerkmanAbstract:TMEM16A was found recently to be a calcium-activated Cl− channel (CaCC). CaCCs perform important functions in cell physiology, including regulation of epithelial secretion, cardiac and neuronal excitability, and smooth muscle contraction. CaCC modulators are of potential utility for treatment of hypertension, diarrhea, and cystic fibrosis. Screening of drug and natural product collections identified tannic Acid as an inhibitor of TMEM16A, with IC50 ∼ 6 μM and ∼100% inhibition at higher concentrations. Tannic Acid inhibited CaCCs in multiple cell types but did not affect CFTR Cl− channels. Structure-activity analysis indicated the requirement of gallic or Digallic Acid substituents on a macromolecular scaffold (gallotannins), as are present in green tea and red wine. Other polyphenolic components of teas and wines, including epicatechin, catechin, and malvidin-3-glucoside, poorly inhibited CaCCs. Remarkably, a 1000-fold dilution of red wine and 100-fold dilution of green tea inhibited CaCCs by >50%. Tannic...
Susana B. Grassino - One of the best experts on this subject based on the ideXlab platform.
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Photoactive films obtained from methacrylo-urethanes tannic Acid-based with potential usage as coating materials : analytic and kinetic studies
Progress in Organic Coatings, 1999Co-Authors: Susana B. Grassino, Miriam C. Strumia, Joël Couve, Marc J.m. AbadieAbstract:Abstract New UV-curable urethane functionalized precursors were synthesized from methacrylic derivatives of tannic Acid (TA) ( m -Digallic Acid), using tolylene 2,4-diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) as major reagents. These products were obtained through two different procedures: two-step and one-step synthetic routes. Thus, Hypermonomers I and II were obtained. Hypermonomer I was prepared via convergent synthesis of two precursors, i.e. tannic Acid methacrylate (Monomer I A ) and TDI–HEMA adduct (Monomer I B ) in a 1 : 1 molar ratio (Route I). On the other hand, Hypermonomer II was obtained in a one-step procedure; the coupling reaction between tannic Acid and TDI (Monomer II A ) was followed by HEMA addition, in a molar ratio TA–TDI–HEMA 1 : 3 : 3 (Route II). To begin with, kinetic and thermodynamic parameters were defined by means of differential photocalorimetry (DPC) to evaluate the following parameters: enthalpy (Δ H ), peak maximum (PM), percent of monomer reacted at peak maximum (RPM %), induction time (IT), order of the initiation reaction ( m ), and rate constant ( k ). The hypermonomers were thermally and photochemically polymerized into films, and the resulting films were characterized by infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR), and thermogravimetric analysis (TGA–DTG). From all these studies, it is clear that the films obtained from Hypermonomer II (Route II) yield compounds of higher crosslinking extent than films from Hypermonomer I (Route I) readily and effectively.
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Novel UV‐autocurable methacrylo‐urethane polymeric films derived from m‐Digallic Acid: Preparation and characterization
Journal of Applied Polymer Science, 1998Co-Authors: Susana B. Grassino, Miriam C. StrumiaAbstract:A new acrylo-urethane film polymer was obtained from methacrylic m-Digallic Acid derivatives. The product was attained either by thermo- or photopolymerization, and the films were characterized by chemical and spectroscopic methods. Other studies of the properties of these polymers were also performed. The main characteristics found were brief curing times achieved with no photoinitiators, good thermal properties, and optical activity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2575–2583, 1998
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novel uv autocurable methacrylo urethane polymeric films derived from m Digallic Acid preparation and characterization
Journal of Applied Polymer Science, 1998Co-Authors: Susana B. Grassino, Miriam C. StrumiaAbstract:A new acrylo-urethane film polymer was obtained from methacrylic m-Digallic Acid derivatives. The product was attained either by thermo- or photopolymerization, and the films were characterized by chemical and spectroscopic methods. Other studies of the properties of these polymers were also performed. The main characteristics found were brief curing times achieved with no photoinitiators, good thermal properties, and optical activity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2575–2583, 1998
Miriam C. Strumia - One of the best experts on this subject based on the ideXlab platform.
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Photoactive films obtained from methacrylo-urethanes tannic Acid-based with potential usage as coating materials : analytic and kinetic studies
Progress in Organic Coatings, 1999Co-Authors: Susana B. Grassino, Miriam C. Strumia, Joël Couve, Marc J.m. AbadieAbstract:Abstract New UV-curable urethane functionalized precursors were synthesized from methacrylic derivatives of tannic Acid (TA) ( m -Digallic Acid), using tolylene 2,4-diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) as major reagents. These products were obtained through two different procedures: two-step and one-step synthetic routes. Thus, Hypermonomers I and II were obtained. Hypermonomer I was prepared via convergent synthesis of two precursors, i.e. tannic Acid methacrylate (Monomer I A ) and TDI–HEMA adduct (Monomer I B ) in a 1 : 1 molar ratio (Route I). On the other hand, Hypermonomer II was obtained in a one-step procedure; the coupling reaction between tannic Acid and TDI (Monomer II A ) was followed by HEMA addition, in a molar ratio TA–TDI–HEMA 1 : 3 : 3 (Route II). To begin with, kinetic and thermodynamic parameters were defined by means of differential photocalorimetry (DPC) to evaluate the following parameters: enthalpy (Δ H ), peak maximum (PM), percent of monomer reacted at peak maximum (RPM %), induction time (IT), order of the initiation reaction ( m ), and rate constant ( k ). The hypermonomers were thermally and photochemically polymerized into films, and the resulting films were characterized by infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR), and thermogravimetric analysis (TGA–DTG). From all these studies, it is clear that the films obtained from Hypermonomer II (Route II) yield compounds of higher crosslinking extent than films from Hypermonomer I (Route I) readily and effectively.
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Novel UV‐autocurable methacrylo‐urethane polymeric films derived from m‐Digallic Acid: Preparation and characterization
Journal of Applied Polymer Science, 1998Co-Authors: Susana B. Grassino, Miriam C. StrumiaAbstract:A new acrylo-urethane film polymer was obtained from methacrylic m-Digallic Acid derivatives. The product was attained either by thermo- or photopolymerization, and the films were characterized by chemical and spectroscopic methods. Other studies of the properties of these polymers were also performed. The main characteristics found were brief curing times achieved with no photoinitiators, good thermal properties, and optical activity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2575–2583, 1998
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novel uv autocurable methacrylo urethane polymeric films derived from m Digallic Acid preparation and characterization
Journal of Applied Polymer Science, 1998Co-Authors: Susana B. Grassino, Miriam C. StrumiaAbstract:A new acrylo-urethane film polymer was obtained from methacrylic m-Digallic Acid derivatives. The product was attained either by thermo- or photopolymerization, and the films were characterized by chemical and spectroscopic methods. Other studies of the properties of these polymers were also performed. The main characteristics found were brief curing times achieved with no photoinitiators, good thermal properties, and optical activity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2575–2583, 1998
Wissem Bhouri - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the apoptotic way induced by Digallic Acid in human lymphoblastoid TK6 cells
Cancer Cell International, 2012Co-Authors: Wissem Bhouri, Ines Skandrani, Kamel Ghedira, Jihed Boubaker, Leila Chekir GhediraAbstract:Background The Digallic Acid (DGA) purified from Pistacia lentiscus . L fruits was investigated for its antiproliferative and apoptotic activities on human lymphoblastoid TK6 cells. Methods We attempt to characterize the apoptotic pathway activated by DGA. Apoptosis was detected by DNA fragmentation, PARP cleavage and by evaluating caspase activities. Results The inhibition of lymphoblastoid cell proliferation was noted from 8.5 μg/ml of DGA. The induction of apoptosis was confirmed by DNA fragmentation and PARP cleavage. We have demonstrated that DGA induces apoptosis by activating the caspase-8 extrinsic pathway. Caspase-3 was also activated in a dose dependent manner. Conclusion In summary, DGA exhibited an apoptosis inductor effect in TK6 cells revealing thus its potential as a cancer-preventive agent.
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Digallic Acid from Pistascia lentiscus fruits induces apoptosis and enhances antioxidant activities.
Phytotherapy research : PTR, 2011Co-Authors: Wissem Bhouri, Ines Skandrani, Mohamed Ben Sghair, Marie-geneviève Djoux Franca, Kamel Ghedira, L. GhediraAbstract:The antioxidant and apoptotic activities of Digallic Acid, isolated from the fruits of Pistascia lentiscus, were investigated. The study demonstrated that Digallic Acid possessed pro-apoptotic effects, as shown by provoking DNA fragmentation of K562 cells. It also revealed a significant antioxidant potential and effective scavenging activity against 2,2-diphenyl-1-picrylhdrazyl (DPPH·) and O2·− radicals, and reduced cupric ions. We conclude that this integrated approach to apoptotic and antioxidant assessment may be useful to maximize the beneficial effects associated with using P. lentiscus derivatives as medicinal and dietary compounds. Copyright © 2011 John Wiley & Sons, Ltd.
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Study of genotoxic, antigenotoxic and antioxidant activities of the Digallic Acid isolated from Pistacia lentiscus fruits.
Toxicology in vitro : an international journal published in association with BIBRA, 2009Co-Authors: Wissem Bhouri, Ines Skandrani, Safa Derbel, Jihed Boubaker, Ines Bouhlel, Mohamed Ben Sghaier, Soumaya Kilani, A Mariotte, Marie G. Dijoux-franca, Kamel GhediraAbstract:Abstract The Digallic Acid obtained from the fruit Pistacia lentiscus exhibits an inhibitory activity against nitrofurantoine and B[ a ]P induced genotoxicity when tested by the SOS chromotest bacterial assay system in the presence of Escherichia coli PQ37 strain. The antioxidant activity of the tested compound was determined by its ability to scavenge the free radical ABTS + , to inhibit the xanthine oxidase, involved in the generation of free radicals, and to inhibit the lipid peroxidation induced by H 2 O 2 in the K562 cell line. Our results revealed that Digallic Acid shows an important free radical scavenging activity towards the ABTS + radical (99%) and protection against lipid peroxidation (68%).