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At least 1,207 records · Page 67Linked to original sources
PubMed2003

Adsorption of flavonoids on resins: hesperidin.

Adsorption of hesperidin from aqueous solutions on styrene-divinylbenzene (SDVB) and acrylic resins was investigated at different pH values (1.5-5.5) and temperatures (10-40 degrees C). Adsorption was not affected by pH variation, whereas it increased on increasing temperature for the SDVB resins and remained substantially unchanged for the acrylic ones. The different behavior of the two types of resins was ascribed to the different wetting, because of their hydrophobic or partially hydrophilic properties, respectively. The equilibrium data at 20 degrees C were determined on 13 commercial resins displaying a wide range of surface areas (S(A), 330-1200 m(2)/g) and pore radii (P(R), 20-260 A). Data were well fitted to the Freundlich isotherm, and its parameters were used to compare the adsorption capacity of different resins. The most effective resin is a SDVB copolymer with the largest S(A) (1200 m(2)/g) and an intermediate P(R) (90 A). The Freundlich constants (K(F)) were rationalized in terms of a two parameter equation, including S(A) and P(R) as independent variables. The adsorption constant increased on increasing both S(A) and P(R) for the resins having P(R) </= 90 A; beyond this limit, the contribution of S(A) was predominant and that of P(R) was slightly negative.

Acrylic Resins↗
PubMed2003

Anthocyanin transformation in Cabernet Sauvignon wine during aging.

Anthocyanins in Cabernet Sauvignon grapes and wines were elucidated by HPLC-MS/MS. Major anthocyanins in Cabernet Sauvignon grape extract are malvidin 3-O-glucoside and malvidin 3-O-acetylglucoside. In matured wine, anthocyanins are transformed to anthocyanin-vinyl derivatives, ethyl bridged anthocyanin-flavanol adducts, and anthocyanin-flavanol adducts. The major anthocyanin pigments are malvidin 3-O-glucoside-pyruvate, malvidin 3-O-acetylglucoside-pyruvate, malvidin 3-O-coumaroylglucoside-pyruvate, malvidin 3-O-glucoside-4-vinylphenol, malvidin 3-O-acetylglucoside-4-vinylphenol, and malvidin 3-O-coumaroylglucoside-4-vinylphenol. The presence of syringetin 3-O-glucoside and syringetin 3-O-acetylglucoside has been established for the first time in grape and wine.

Anthocyanins↗
PubMed2005

Simple saponification method for the quantitative determination of carotenoids in green vegetables.

A simple, reliable, and gentle saponification method for the quantitative determination of carotenoids in green vegetables was developed. The method involves an extraction procedure with acetone and the selective removal of the chlorophylls and esterified fatty acids from the organic phase using a strongly basic resin (Ambersep 900 OH). Extracts from common green vegetables (beans, broccoli, green bell pepper, chive, lettuce, parsley, peas, and spinach) were analyzed by high-performance liquid chromatography (HPLC) for their content of major carotenoids before and after action of Ambersep 900 OH. The mean recovery percentages for most carotenoids [(all-E)-violaxanthin, (all-E)-lutein epoxide, (all-E)-lutein, neolutein A, and (all-E)-beta-carotene] after saponification of the vegetable extracts with Ambersep 900 OH were close to 100% (99-104%), while the mean recovery percentages of (9'Z)-neoxanthin increased to 119% and that of (all-E)-neoxanthin and neolutein B decreased to 90% and 72%, respectively.

Carotenoids↗
PubMed1999

Recovery of hesperidin from orange peel by concentration of extracts on styrene-divinylbenzene resin.

This paper describes a new procedure for obtaining hesperidin from the waste orange peel of the citrus industry. It is based on the adsorption of dilute extracts of hesperidin on a styrene-divinylbenzene (SDVB) resin and the desorption in much more reduced volumes by means of alkaline eluents. Hesperidin immediately precipitates with good yield and high purity after acidification of the concentrated solutions, thus overcoming disadvantages due to the high dilution. Different experiments were carried out to examine operating conditions in each phase of the process. Hesperidin was extracted from peel with an aqueous saturated Ca(OH)(2) solution, allowing precipitation of calcium pectates from colloidal pectins that can interfere in the subsequent phases of adsorption and separation of hesperidin. The clear extracts were neutralized to optimize adsorption on resin. The most effective eluent was 0.5 N NaOH solution containing 10% ethanol. Recycling of the crystallization liquor improved the yield and purity of the product and reduced the acid amount required for neutralizing fresh alkaline extracts. Resin must be washed after each adsorption-desorption cycle and regenerated after five cycles. Results can constitute a useful starting point for an industrial application. A flow scheme of the process is also reported.

Adsorption↗
PubMed1990

Diels-Alder adducts of vinyl porphyrins: synthesis and in vivo photodynamic effect against a rat bladder tumor.

Benzoporphyrin derivatives have been proposed as potential photosensitizers for photodynamic therapy. We have prepared a number of benzoporphyrin derivatives and tested their effect, in combination with red light, on the N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) induced rat bladder tumor (AY-27) transplanted into Fischer CDF(F344)/CrlBr rats. Tetracyanoethylene (TCNE) adducts showed very little activity, which may be attributable to their poor tumor uptake or to chemical instability of the adduct under physiological conditions. However, dimethyl acetylenedicarboxylate (DMAD) adducts tested showed greater cytotoxic effect than hematoporphyrin derivative and similar activities to metallopurpurins when tested under the same protocol.

Acetylene↗
PubMed1977

Polynucleotide analogues. Copolymers of vinyl bases with acrylic acid, methylacrylic acid, acrylamide, and 1-vinylpyrrolidone.

Preliminary studies are reported on the synthesis and testing of substituted vinyl polymers that are designed to have sequence specific affinity for polyribonucleic acids. Copolymers of 1-vinyluracil with acrylic acid, 2-methylacrylic acid, or 1-vinyl-2-pyrrolidone were prepared by gamma-irradiation to give the respective polymers 1,3, and 4. Similarly, 9-vinyladenine yielded copolymeric products 5 and 6 with acrylic acid or 2-methylacrylic acid. Radical initiated polymerization of 9-vinyladenine with acrylamide yielded copolymer 7. The products were characterized by elemental analysis and ultraviolet, infrared, and nuclear magnetic resonance spectroscopy. No hypochromicity could be detected on mixing polymers 1-4 with poly(adenylic acid). The acrylic acid copolymer 2 containing a high ratio of vinyluracil was a potent inhibitor of poly(adenylic acid) coded polylysine synthesis in an in vitro system. Polymers 6 and 7, containing a high proportion of vinyladenine, inhibited poly(uridylic acid) coded poly(phenylalanine) synthesis.

Acrylamides↗
PubMed1976

Antimalarials. 11. 2-Vinylogs of substituted 2-aryl-4-quinoline amino alcohols.

3-(P-Chlorobenzylidene)-5, 7-dimethyl-2, 3-dihydro-1H-cyclopenta[b]quinoline-9-(di-n-butylaminomethyl)methanol and 2-[beta-(p-chlorostyryl)]-6, 8-dimethylquinoline-4-(di-n-butylaminomethyl)methanol were synthesized from 6, -8-dimethyl-4-hydroxycarbostyril by 3, 3-dichlorination, dimethoxylation th the 3-ketal, basic hydrolysis to the glyoxal acetal, Pfitzinger condensation with cylopentanone or acetone to the 2, 3-trimethylene or 2-methylquinoline, condensation with p-ClPhCHO at the 2-methylene or 2-methyl group, hydrolysis to the 4-quinaldehyde, methylenation to the epoxide, and condensation with Bu2NH. Both were curative against P. berghei in mice. The first was the more effective: active at 10 mg/kg, completely curative at 40 mg/kg, and only mildly phototoxic in animals.

Animals↗
PubMed1975

Chemistry of cephalosporin antibiotics. 28. Preparation and biological activity of 3-(substituted)vinyl cephalosporins.

3-(Substituted)vinylcephem nuclei have been prepared by the reaction of 3-formylcephem derivatives with stabilized phosphoranes. Appropriate synthetic steps allowed preparation of a series of 3-ethoxycarbonylvinyl- and 3-carboxyvinylcephem derivatives bearing a variety of 7-acylamino functions. The phenoxyacetyl and thiopheneacetyl derivatives of the 3-cyanovinylcephem nucleus were also prepared. Although general gram-positive activity was comparable to cephalothin in many cases, against penicillin G resistant Staphylococcus aureus, the new cephalosporins were of low effectiveness. The 3-(substituted)vinyl cephalosporins had good activity against a number of gram-negative organisms. In some cases, this activity was excellent. The N-acetyl analogs had surprisingly good activity relative to N-acetyl-7-ACA. The phenylmalonoyl side-chain derivatives were shown to have an unusual antibacterial spectrum expansion (relative to previously known cephalosporins) to include activity against Serratia marcescens and Pseudomonas aeruginosa.

Bacillus subtilis↗
PubMed2003

Development of a water-soluble matrix metalloproteinase inhibitor as an intra-arterial infusion drug for prevention of restenosis after angioplasty.

To prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA) and/or stenting of atherosclerotic stenosed arteries, we designed and developed two water-soluble matrix metalloproteinases (MMPs) inhibitors. The first inhibitor was monomeric in type and was chemically synthesized by succinylation of the synthetic MMP inhibitor, N-hydroxy-5-hydroxy-2(S)-methyl-4(S)-(4-phenoxybenzoyl)aminopentanamide (ONO-M11-335). The second inhibitor was polymeric and was a radical copolymer of the vinyl derivative of ONO-M11-335 and a water-soluble monomer, N,N-dimethylacrylamide (DMAAm). For the second inhibitor, NMR analyses and UV-vis spectra measurements showed that the content of the ONO-M11-335 unit in the copolymers (M(n); ca. 10 000 and 20 000 by GPC measurements) was about 8 per molecule. The MMP inhibitors were all highly soluble in water, even under neutral pH. The succinylated derivative markedly inhibited MMP-2, MMP-9, and MMP-12 in vitro, as did ONO-M11-335. In contrast the copolymers, which can maintain effective plasma levels for extended periods by prevention of hepatic uptake, showed a ca. 100-fold reduced inhibition activity. Such water-soluble MMP inhibitors, developed in this study, may potentially be useful as an intra-arterial infusion drug for vascular injury.

Acrylamides↗
PubMed2003

Benzoylalanine-derived ketoamides carrying vinylbenzyl amino residues: discovery of potent water-soluble calpain inhibitors with oral bioavailability.

Novel benzoylalanine-derived ketoamides were prepared and evaluated for calpain I inhibition. Derivatives carrying vinylbenzyl amino residues in the P(2)-P(3) region inhibited calpain in nanomolar concentrations and thus represent a novel class of nonpeptidic calpain inhibitors. Selected examples exhibited an improved pharmacokinetic profile including improved water-solubility and metabolic stability. In particular, these calpain inhibitors showed oral bioavailability in rats as demonstrated by N-(1-benzyl-2-carbamoyl-2-oxoethyl)-2-[E-2-(4-diethylaminomethylphenyl)ethen-1-yl]benzamide (5d). The closely related derivative N-(1-carbamoyl-1-oxohex-1-yl)-2-[E-2-(4-dimethylaminomethylphenyl)-ethen-1-yl]benzamide (5b) was evaluated for neuroprotective efficacy after experimental traumatic brain injury in a fluid percussion model in rats. When administered after injury, 5b reduced the number of damaged neurons by 41%, and this result would be in line with the suggested neuroprotective efficacy of calpain inhibition.

Administration, Oral↗