Absorption of aminoethyl cysteine ketimine decarboxylated dimer in mice: effect on plasma antioxidant potential.

Aminoethylcysteine ketimine decarboxylated dimer (AECK-DD) is a natural compound with antioxidant properties of a new family of sulfur-containing amino acids. It has been detected in human urine and plasma, in mammalian cerebellum, and in dietary vegetables. In this study, we first demonstrate the absorption of AECK-DD in mice from AECK-DD-supplemented diet, using both liquid chromatography with electrochemical detection and gas chromatography coupled with mass spectrometry. AECK-DD circulates in the plasma of supplemented mice at a micromolar concentration and is incorporated in liver tissue. The absorption of AECK-DD is dose dependent. The dehydrogenation product of AECK-DD was also identified in plasma and liver of mice fed the AECK-DD-supplemented diet. A significant increase in plasma antioxidant potential was measured in mice fed AECK-DD-supplemented diet with respect to mice fed the control diet. These results demonstrate for the first time the absorption of AECK-DD from diet and the physiological relevance of this compound through its antioxidant action in vivo.

Antioxidant properties of aminoethylcysteine ketimine decarboxylated dimer: a review.

Aminoethylcysteine ketimine decarboxylated dimer is a natural sulfur-containing compound detected in human plasma and urine, in mammalian brain and in many common edible vegetables. Over the past decade many studies have been undertaken to identify its metabolic role. Attention has been focused on its antioxidant properties and on its reactivity against oxygen and nitrogen reactive species. These properties have been studied in different model systems starting from plasma lipoproteins to specific cellular lines. All these studies report that aminoethylcysteine ketimine decarboxylated dimer is able to interact both with reactive oxygen and nitrogen species (hydrogen peroxide, superoxide anion, hydroxyl radical, peroxynitrite and its derivatives). Its antioxidant activity is similar to that of Vitamin E while higher than other hydrophilic antioxidants, such as trolox and N-acetylcysteine.

Chromane derivatives of small aromatic molecules: Chemoenzymatic synthesis and growth inhibitory activity on human tumor cell line LoVo WT.

Aromatic substrates tyrosol (p-hydroxyphenylethanol) and 2,6-dihydroxynaphthalene (2,6-DHN) were converted into chromane derivatives by means of chemoenzymatic reactions catalyzed by the aromatic prenyltransferase of bacterial origin NovQ, using dimethylallyl bromide as allylic substrate instead of the natural isoprenyl pyrophosphate substrate. Stereoselective prenylation occurred in o-position with respect to the phenol hydroxyl in both compounds. Prenylated derivatives were readily converted into chromane products via a selective 6-endo-trig cyclization involving the oxygen atom from the phenol moiety and the double bond of the prenyl substituent, a process catalyzed by FeCl(3). These findings set up the basis of a most convenient two-step, one-pot process which allows for easy recovery of the chromane products in high yields. The chromane derivatives thus obtained were tested for cytotoxicity and pro-apoptotic activity using LoVo WT cells, a line of human colon adenocarcinoma.

Synthesis and characterization of a dehydrogenation product arising from the oxidation of aminoethylcysteine ketimine decarboxylated dimer.

While investigating the antioxidant properties of aminoethylcysteine ketimine decarboxylated dimer (1) (a natural substance occurring in biological fluids such as human urine and plasma and in bovine cerebellum), a previously unreported oxidation product was obtained. This compound was identified and characterized through comparison with an authentic sample prepared via Pd-catalyzed dehydrogenation of 1. This molecule is an example of an alternative oxidation pathway involving 1.

The desaturase from Bacillus subtilis, a promising tool for the selective olefination of phospholipids.

The Delta5-desaturase from Bacillus subtilis has been cloned in Escherichia coli BL21 cells and its enzyme activity has been investigated as a function of temperature and oxygenation by analyzing methyl ester adducts from the total lipid extract in GC-MS measurements. The present data bring out that the activity of recombinant Delta5-desaturase, at 20-22 degrees C and 20% oxygen, is surprisingly high yielding 22% of C16:1,Delta5 (5-cis-palmitoleic acid) and 13% C18:2, Delta5 Delta11 (efedrenic acid). Lower amounts of other mono- and doubly-Delta5-unsaturated fatty acids were also detected. These findings demonstrate that Delta5-desaturase can accept a multiplicity of substrates and is endowed with an unprecedented activity among other acyl-lipid desaturases thus representing a unique tool for the production of rare Delta5 unsaturated fatty acid derivatives.

Identification of aminoethylcysteine ketimine decarboxylated dimer, a natural antioxidant, in dietary vegetables.

Aminoethylcysteine ketimine decarboxylated dimer (simply named dimer) is a natural sulfur-containing tricyclic compound detected, until now, in human urine, bovine cerebellum, and human plasma. Recently, the antioxidant properties of this compound have been demonstrated. In this investigation, the presence of aminoethylcysteine ketimine decarboxylated dimer was identified in garlic, spinach, tomato, asparagus, aubergine, onion, pepper, and courgette. Identification of this compound in dietary vegetables was performed using gas chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. Results from GC analysis range in the order of 10(-4) micromol of dimer/g for all the tested vegetables. These results and the lack of a demonstrated biosynthetic pathway in humans might account for a dietary supply of this molecule.