High-resolution liquid chromatography/electrospray ionization time-of-flight mass spectrometry combined with liquid chromatography/electrospray ionization tandem mass spectrometry to identify polyphenols from grape antioxidant dietary fiber.

Grape antioxidant dietary fiber (GADF) is a dietary supplement that combines the benefits of both fiber and antioxidants that help prevent cancer and cardiovascular diseases. The antioxidant polyphenolic components in GADF probably help prevent cancer in the digestive tract, where they are bioavailable. Mass spectrometry coupled to liquid chromatography is a powerful tool for the analysis of complex plant derivatives such as GADF.

A monolayer study on interactions of docetaxel with model lipid membranes.

Docetaxel (DCT) is an antineoplastic drug for the treatment of a wide spectrum of cancers. DCT surface properties as well as miscibility studies with l-alpha-dipalmitoyl phosphatidylcholine (DPPC), which constitutes the main component of biological membranes, are comprehensively described in this contribution. Penetration studies have revealed that when DCT is injected under DPPC monolayers compressed to different surface pressures, it penetrates into the lipid monolayer promoting an increase in the surface pressure.

Highly galloylated tannin fractions from witch hazel (Hamamelis virginiana) bark: electron transfer capacity, in vitro antioxidant activity, and effects on skin-related cells.

Witch hazel ( Hammamelis virginiana) bark is a rich source of both condensed and hydrolizable oligomeric tannins. From a polyphenolic extract soluble in both ethyl acetate and water, we have generated fractions rich in pyrogallol-containing polyphenols (proanthocyanidins, gallotannins, and gallates). The mixtures were highly active as free radical scavengers against ABTS, DPPH (hydrogen donation and electron transfer), and HNTTM (electron transfer).

Fructose-6-phosphate aldolase in organic synthesis: preparation of D-fagomine, N-alkylated derivatives, and preliminary biological assays.

[Structure: see text] D-fructose-6-phosphate aldolase (FSA) mediates a novel straightforward two-step chemo-enzymatic synthesis of D-fagomine and some of its N-alkylated derivatives in 51% isolated yield and 99% de. The key step is the FSA-catalyzed aldol addition of simple dihydroxyacetone (DHA) to N-Cbz-3-aminopropanal. The use of FSA greatly simplifies the enzymatic procedures that used dihydroxyacetonephosphate or DHA/esters.

Electron-transfer capacity of catechin derivatives and influence on the cell cycle and apoptosis in HT29 cells.

Galloylated and nongalloylated catechin conjugates with cysteine derivatives have been synthesized and evaluated for their capacity to scavenge free radicals and to influence crucial functions (cell cycle, apoptosis) in HT29 colon carcinoma cells. We show that the nonphenolic part of the molecule modified the capacity of catechins to donate hydrogen atoms and to transfer electrons to free radicals. Nongalloylated derivatives did not significantly influence either the cell cycle or apoptosis.

Efficient preparation of catechin thio conjugates by one step extraction/depolymerization of pine (Pinus pinaster) bark procyanidins.

The skin penetrating antioxidant cysteamine derivative of (-)-epicatechin as well as other thio conjugates were efficiently obtained with high yields from pine (Pinus pinaster) bark by simultaneous one pot extraction and depolymerization using water and cysteamine hydrochloride. The influence of the concentration of bark, acid, and cysteamine, as well as the reaction time on the total conversion, was studied. The total conversion into the epicatechin and catechin conjugates was as high as 47 g/kg pine bark with 1666 g cysteamine/kg bark and 28 g/kg with 166 g cysteamine/kg bark.

Conjugation of catechins with cysteine generates antioxidant compounds with enhanced neuroprotective activity.

Antioxidant compounds derived from the conjugation of (-)-epicatechin and (-)-epicatechin 3-O-gallate with cysteine and cysteine derivatives protected HT-22 nerve cells (EC50 between 36 and 65 microM) from death triggered by glutamate while underivatized (-)-epicatechin was almost inactive (EC50=610 microM). Differences in free radical scavenging capacity (DPPH assay) could not account for the improvement in neuroprotective activity upon derivatization of (-)-epicatechin with thiols. Moreover, while the gallate-containing compounds are more efficient radical scavengers than their non-galloylated counterparts, they are only equally or less potent as neuroprotective agents.

Procyanidin fractions from pine (Pinus pinaster) bark: radical scavenging power in solution, antioxidant activity in emulsion, and antiproliferative effect in melanoma cells.

Pine (Pinus pinaster) bark is a rich source of procyanidin oligomers. From a total polyphenolic extract, we have generated fractions of different procyanidin composition. The mixtures, devoid of gallate esters, were active as free radical scavengers against ABTS(*+), DPPH, and HNTTM.

Efficient one pot extraction and depolymerization of grape (Vitis vinifera) pomace procyanidins for the preparation of antioxidant thio-conjugates.

Antioxidant thio-conjugates were obtained from white grape pomace by a clean and efficient one pot extraction and depolymerization method using water and cysteamine hydrochloride. To evaluate the potential of grape pomaces of different origins as sources of proanthocyanidins and conjugates, we conducted varietal comparative studies of polyphenol content, antioxidant power, and procyanidin composition. Xarel.

Antiproliferative effect of antioxidant polyphenols from grape in murine Hepa-1c1c7.

Background: Grapes and wine contain high concentrations of polyphenolic compounds. Although their cancer protective effect has been well documented, their activity as anticarcinogens should be cautiously considered since the molecular bases of action and their applicability to human cancer prevention are still unclear.

Aim Of The Study: We studied the antioxidant/antiradical activity and the antiproliferative effect in vitro of different polyphenolic mixtures, extracted from grapes and fractionated through RP-HPLC.

Valorization of grape (Vitis vinifera) byproducts. Antioxidant and biological properties of polyphenolic fractions differing in procyanidin composition and flavonol content.

Many byproducts and wastes generated by agroindustries contain polyphenols with potential application as food antioxidants and preventive agents against skin cancer and other diseases. The performance of polyphenolic fractions from Parellada grape (Vitis vinifera) pomace as antioxidants in different physicochemical environments was tested. Fractions containing oligomers with mean degree of polymerization between 3 and 4 and percentage galloylation ca.

Cation-exchange micropreparative separation of galloylated and non-galloylated sulphur conjugated catechins.

Catechin conjugates bearing an amino function can be separated from underivatized monomers by cation-exchange chromatography. Here, chromatographic conditions for the separation of epicatechin gallate-containing conjugates from the non-galloylated conjugates at micropreparative scale are described. The separation was achieved by exploiting either the hydrophobic or hydrophilic interactions of the conjugates with the core polymer.

Cysteinyl-flavan-3-ol conjugates from grape procyanidins. Antioxidant and antiproliferative properties.

New bio-based antioxidant compounds have been obtained by depolymerisation of grape polymeric flavanols in the presence of cysteine. Their preparation and purification, as well as their antiradical/antioxidant and antiproliferative properties are reported. 4beta-(S-cysteinyl)epicatechin 5, 4beta-(S-cysteinyl)catechin 6 and 4beta-(S-cysteinyl)epicatechin 3-O-gallate 7 were efficiently purified from the crude depolymerised mixture by cation-exchange chromatography and preparative reversed-phase chromatography.

New flavanol derivatives from grape (Vitis vinifera) byproducts. Antioxidant aminoethylthio-flavan-3-ol conjugates from a polymeric waste fraction used as a source of flavanols.

A new family of antioxidants has been obtained from a residual fraction of polymeric polyphenols of grape origin. The integral exploitation of resources is important in any sustainable production scheme. Many byproducts and residues generated by the agroindustries contain polyphenols with potential application as preventative agents against cancer and cardiovascular diseases.

Purification of non-toxic, biodegradable arginine-based gemini surfactants, bis(Args), by ion exchange chromatography.

This paper presents an environmentally improved procedure for the preparative purification of a series of arginine-based gemini surfactants. The technique used was cation-exchange chromatography. Mixtures of boric-borate buffer, co-solvent (ethanol), and sodium chloride were tested as eluents.