The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://http://dspace.unitus.it:80 2013-05-21T11:41:16Z 2013-05-21T11:41:16Z Bernini, Roberta Crisante, Fernanda Ginnasi, Maria Cristina http://hdl.handle.net/2067/1296 2011-06-28T15:04:00Z 2010-12-31T23:00:00Z

Title: A Convenient and Safe O-Methylation of Flavonoids with Dimethyl Carbonate (DMC) Authors: Bernini, Roberta; Crisante, Fernanda; Ginnasi, Maria Cristina Abstract: Dietary flavonoids exhibit beneficial health effects. Several epidemiological studies have focused on their biological activities, including antioxidant, antibacterial, antiviral, anti-inflammatory and cardiovascular properties. More recently, these compounds have shown to be promising cancer chemopreventive agents in cell culture studies. In particular, O-methylated flavonoids exhibited a superior anticancer activity than the corresponding hydroxylated derivatives being more resistant to the hepatic metabolism and showing a higher intestinal absorption. In this communication we describe a convenient and efficient procedure in order to prepare a large panel of mono- and dimethylated flavonoids by using dimethyl carbonate (DMC), an ecofriendly and non toxic chemical, which plays the role of both solvent and reagent. In order to promote the methylation reaction under mild and practical conditions, 1,8-diazabicyclo[5.4.0]undec-7- ene (DBU) was added in the solution; methylated flavonoids were isolated in high yields and with a high degree of purity. This methylation protocol avoids the use of hazardous and high toxic reagents (diazomethane, dimethyl sulfate, methyl iodide). Description: L'articolo è disponibile sul sito dell'editore: www.mdpi.com

2010-12-31T23:00:00Z Bernini, Roberta Mincione, Enrico Crisante, Fernanda Barontini, Maurizio Fabrizi, Giancarlo Gentili, Patrizia http://hdl.handle.net/2067/1881 2011-06-28T13:21:08Z 2006-12-31T23:00:00Z

Title: Chemoselective and efficient carboxymethylation of the alcoholic chain of phenols by dimethyl carbonate (DMC). Authors: Bernini, Roberta; Mincione, Enrico; Crisante, Fernanda; Barontini, Maurizio; Fabrizi, Giancarlo; Gentili, Patrizia Abstract: The efficiency of dimethyl carbonate (DMC) as chemoselective carbomethoxylating agent of the alcoholic chain of phenols has been investigated. In the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or sulfuric acid as catalysts. New carbomethoxylated phenolic compounds were obtained in quantitative yields. A new efficient derivatization of the aliphatic alcoholic chain of the precious natural hydroxytyrosol is described, which increases the lipophilicity of the hydroxytyrosol. The antioxidant activity of this new carboxymethylated hydroxytyrosol 8 has been investigated using DPPH radical scavenging test. The results showed that this new compound has an antioxidant activity similar to hydroxytyrosol. Description: L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com

2006-12-31T23:00:00Z Bernini, Roberta Crisante, Fernanda Merendino, Nicolò Molinari, Romina Soldatelli, Maria Chiara Velotti, Francesca http://hdl.handle.net/2067/1571 2011-06-30T16:37:13Z 2009-12-31T23:00:00Z

Title: Synthesis of a novel ester of hydroxytyrosol and lipoic acid exhibiting an antiproliferative effect on human colon cancer HT-29 cells Authors: Bernini, Roberta; Crisante, Fernanda; Merendino, Nicolò; Molinari, Romina; Soldatelli, Maria Chiara; Velotti, Francesca Abstract: A novel hydroxytyrosol-lipoic acid derivative has been synthesized. Key steps are an esterification reaction between tyrosol and -lipoic acid derivatives and a regioselective aromatic hydroxylation of the monohydroxylated ester performed by 2-iodoxybenzoic acid (IBX) followed by an in situ reduction with sodium dithionite (Na2S2O4). The novel ester exhibited an antiproliferative effect on the human colorectal adenocarcinoma HT-29 cell line significantly more potent than its parent compounds

2009-12-31T23:00:00Z Bernini, Roberta Crisante, Fernanda Merendino, Nicolò Molinari, Romina Soldatelli, Maria Chiara Velotti, Francesca http://hdl.handle.net/2067/1581 2011-09-23T08:08:31Z 2009-12-31T23:00:00Z

Title: Synthesis of a novel ester of hydroxytyrosol and lipoic acid exhibiting an antiproliferative effect on human colon cancer HT-29 cells Authors: Bernini, Roberta; Crisante, Fernanda; Merendino, Nicolò; Molinari, Romina; Soldatelli, Maria Chiara; Velotti, Francesca Abstract: A novel hydroxytyrosol-lipoic acid derivative has been synthesized. Key steps are an esterification reaction between tyrosol and cJipoic acid derivatives and a regioselective aromatic hydroxylation ofthe monohydroxylated ester performed by 2-iodoxybenzoic acid (IBX) followed by an in situ reductionw ith sodium dithionite (Na2S2O4T).h e novel estere xhibited an antiproliferative effect on the human colorectal adenocarcinoma HT-29 cell line signifrcantly more potent than its parent compounds.

2009-12-31T23:00:00Z Bernini, Roberta Barontini, Maurizio Spatafora, Carmela http://hdl.handle.net/2067/1734 2011-06-30T14:20:14Z 2008-12-31T23:00:00Z

Title: New lipophilic piceatannol derivatives exhibiting antioxidant activity prepared by aromatic hydroxylation with 2-iodoxybenzoic acid (IBX) Authors: Bernini, Roberta; Barontini, Maurizio; Spatafora, Carmela Abstract: Piceatannol (E-3,5,3’,4’ tetrahydroxystilbene) is a phytoalexin synthesized in grapes in response to stress conditions. It exhibits strong antioxidant and antileukaemic activities due to the presence of the catechol moiety. To modify some physical properties like solubility, and miscibility in non-aqueous media some new previously unreported piceatannol derivatives having lipophilic chains on the A-ring were prepared in good yields by a simple and efficient procedure. The key step was a chemo- and regioselective aromatic hydroxylation with 2-iodoxybenzoic acid (IBX). The new compounds showed antioxidant activity and seemed promising for possible applications as multifunctional emulsifiers in food, cosmetic and pharmaceutical fields. Description: L'articolo è disponibile sul sito dell'editore: http://www.mdpi.com

2008-12-31T23:00:00Z Bernini, Roberta Mincione, Enrico Barontini, Maurizio Crisante, Fernanda Fabrizi, Giancarlo Gambacorta, Augusto http://hdl.handle.net/2067/1879 2011-06-29T14:21:07Z 2006-12-31T23:00:00Z

Title: Dimethyl carbonate: an environmentally friendly solvent for hydrogen peroxide (H2O2)/methyltrioxorhenium (CH3ReO3, MTO) catalytic oxidations Authors: Bernini, Roberta; Mincione, Enrico; Barontini, Maurizio; Crisante, Fernanda; Fabrizi, Giancarlo; Gambacorta, Augusto Abstract: Environmentally friendly oxidations of various organic compounds with the hydrogen peroxide (H2O2)/methyltrioxorhenium(CH3ReO3, MTO) catalytic system have been described in dimethyl carbonate (DMC), a cheap commercially available and benign chemical having interesting solvating properties, low toxicity and high biodegradability. Oxidations proceeded with good conversions and in good yields. Spectrophotometric analysis demonstrated that the [CH3ReO(O–O)2] complex was formed in DMC and that it was stable for several days at room temperature. Description: L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com

2006-12-31T23:00:00Z Bernini, Roberta Barontini, Maurizio Mosesso, Pasquale Pepe, Gaetano Willfoer, Stefan M. Sjoeholm, Rainer E. Eklund, Patrick C. Saladino, Raffaele http://hdl.handle.net/2067/1347 2011-06-30T15:51:30Z 2008-12-31T23:00:00Z

Title: A selective de-O-methylation of guaiacyl lignans to corresponding catechol derivatives by 2-iodoxybenzoic acid (IBX). The role of the catechol moiety on the toxicity of lignans Authors: Bernini, Roberta; Barontini, Maurizio; Mosesso, Pasquale; Pepe, Gaetano; Willfoer, Stefan M.; Sjoeholm, Rainer E.; Eklund, Patrick C.; Saladino, Raffaele Abstract: We report here the first selective de-O-methylation of a large panel of guaiacyl lignans to the corresponding catechol derivatives by using IBX as primary oxidant under green conditions (dimethyl carbonate–H2O solvent) through an in situ reduction procedure. The influence of the catechol moiety on the cytotoxicity and genotoxicity of new lignan derivatives has been investigated. The results obtained indicated that the presence of the catechol moiety sharply enhances the clastogenic potential (e.g. induction of chromosomal aberrations), the cytotoxicity and the modulation of cell cycle progression with respect to the parent compounds. Thus, despite the in vitro antioxidant activity usually described for catechol derivatives, our results show for the first time the generation of a clastogenic potential, highly indicative of a long-term genetic and cancer risk Description: L'articolo è disponibile sul sito dell'editore: http://www.rsc.org

2008-12-31T23:00:00Z Saladino, Raffaele Ginnasi, Maria Cristina Collalto, Daniela Bernini, Roberta Crestini, Claudia http://hdl.handle.net/2067/1795 2011-06-29T15:42:40Z 2009-12-31T23:00:00Z

Title: An efficient and selective epoxidation of olefins with novel methyltrioxorhenium/(fluorous ponytailed) 2,2′-bipyridine catalysts Authors: Saladino, Raffaele; Ginnasi, Maria Cristina; Collalto, Daniela; Bernini, Roberta; Crestini, Claudia Abstract: Novel complexes between methyltrioxorhenium (MTO) and bis(fluorous- ponytailed) 2,2′bipyridines (bpy-Fn) were synthesized and used for the oxidation of alkenes with hydrogen peroxide under fluorous catalysis. High conversions and yields of the corresponding epoxides were obtained. Description: L'articolo è disponibile sul sito dell'editore: http://www.onlinelibrary.wiley.com

2009-12-31T23:00:00Z