Synthesis of N-acetyl-d-lactosamine (Gal-β[1→4]GlcNAc, LacNAc) catalyzed by β-galactosidase from Thermus thermophilus (TTP0042) is affected by side reactions that give as result very low yields (about 20%) of LAcNAc when the reaction is performed in buffer. The process is improved (up to 91% ...

Lactosamine (β-d-Galp-(1→4)-d-GlcN) was isolated from bovine milk sampled after intravenous infusion of glucosamine through the jugular vein of a lactating cow. The chemical structure was established by 2D NMR spectroscopy and electrospray ionisation mass spectrometry (ESIMS). Selected ion mon...

The Heyns rearrangement is possibly one of the oldest, easiest and most economic ways to synthesise 2-deoxy-2-amino sugars. Initially reported yields were disappointingly low, but in the late 90s Wrodnigg and Stütz discovered modified reaction conditions that gave substantially increased yields...

Ternary core/shell CdSeS/ZnS-QDs coated with N-acetyl lactosamine was prepared as a fluorescent probe to study the interactions of N-acetyl lactosamine and galectin-3. The synthesis of N-acetyl lactosamine was achieved through the ‘azidoiodoglycosylation’ method. The amount of ligand coated on...

Combination of biophysical and structural techniques allowed characterizing and uncovering the mechanisms underlying increased binding affinity of lactosamine derivatives for galectin 3. In particular, complementing information gathered from X-ray crystallography, native mass spectrometry and is...

A scalable approach for the preparation of lactosamine hydrochloride from lactulose is described. The reported procedure is based on the preparation of a new dibenzylamino derivative of lactosamine hydrochloride. Lactosamine hydrochloride was prepared in a two-pot reaction sequence from commerci...

In this work we have examined the use of a photodiode-array detector to identify unknown peaks correspoding to procyanidins and related compounds. The type of flavan-3-ol unit can be recognised from the absorption maximum (278.9) nm for catechin and epicatechin, and 270.6 nm for epigallocatechin...

Six galloyl-substituted procyanidin B1 and B2, 3-O-gallate, 3″-O-gallate, and 3,3″-di-O-gallate, were systematically synthesized with the condensation method using TMSOTf as a catalyst. Their ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity were also investiga...

Fractionation of a grape (Vitis vinifera) seed extract yielded various natural procyanidin dimers and trimers isolated and identified for the first time in grapes: procyanidin dimers B5 [epicatechin-(4β → 6)-epicatechin], B6 [catechin-(4α → 6)-catechin] and B8 [catechin-(4α → 6)-epicatechi...

The present knowledge on the qualitative and quantitative analysis of procyanidins is reviewed. Procyanidins belong to the class of natural products known as proanthocyanidins or condensed polyphenols. The instability of procyanidins should be considered throughout sample collection, storage and...

The antioxidant activity of catechins and oligomeric procyanidins against low density lipoproteins peroxidation was studied by means of three distinct methods: cis-parinaric acid fluorescence decay, conjugated-dienes detection, and oxygen consumption. A relationship between the radical trapping ...

Intermolecular copigmentation between malvidin-3-O-glucoside (oenin) and several procyanidins of a homogeneous series in a wine model solution (pH 3.6, in hydroalcoholic (12%) citrate–phosphate buffer at a ionic strength of 0.2 M) was studied by UV–Vis spectroscopy. The effects of structural f...

High-speed counter-current chromatography (HSCCC) has been applied to the separation of grape seed procyanidins. The isolation of dimeric to tetrameric procyanidins is achieved after removing the polymeric compounds by solvent precipitation. An additional clean-up by solid-phase extraction on po...

In this work, an efficient method for preparative separation of procyanidins from raw cacao bean extract by high-speed counter-current chromatography (HSCCC) was developed. Under the optimized solvent system of n-hexane-ethyl acetate-water (1:50:50, v/v/v) with a combination of head–tail and ta...

The main procyanidins, including dimeric B2 and B5, trimeric C1, tetrameric and pentameric procyanidins, were isolated from unroasted cocoa beans (Theobroma cacao L.) using various techniques of countercurrent chromatography, such as high-speed countercurrent chromatography (HSCCC), low-speed ro...

Polymeric procyanidins (PPCs) were the major constituents of procyanidins, while they have poor bioactivity. To better utilize PPCs, a semisynthetic approach for converting PPCs to oligomeric procyanidins (OPCs) was proposed. Grape seed PPCs were simultaneously reacted with catechin (C) and epic...

Teucrium chamaedrys L. (Labiatae), a herb used to combat obesity, can occasionally cause hepatitis. All mutagenicity tests done were negative. After 13 weeks of administration by oral route in Sprague Dawley rats T. chamaedrys proved to be well tolerated at 0.056 g kg−1 day−1 (i.e. 0.4 mg kg−1 d...

The development of a novel solvent-partition method for measuring the interaction between nucleic acids and drugs of limited water solubility is described. Factors relevant to the choice of a suitable water-immiscible solvent are summarised. i-Amyl acetate was selected for studying the binding o...

Acid hydrolysis of Triostin C proved that the constituents were quinoxaline-2-carboxylic acid (2 moles), d-serine (2 moles), l-alanine (2 moles), N,N′-dimethyl-l-cystine (1 mole), and N,γ-dimethyl-l-alloisoleucine (2 moles). The sequence was proved to be in the order given above and lactone li...

Six or seven triostin-binding sites have been identified in a 160-base-pair DNA restriction fragment containing the tyr T promoter sequence. Each is centred round a CpG step, and the minimum binding site-size appears to be six base pairs. The sites are practically the same as those reported for ...