Sandra Muck

Direct chromatographic resolution of carnitine and O-acylcarnitine enantiomers on a teicoplanin-bonded chiral stationary phase

R-(-)-Carnitine (vitamin B(T)) plays an important role in human energy metabolism, by facilitating the transport of long-chained fatty acids across the mitochondrial membranes. Its (S)-enantiomer acts as a competitive inhibitor of carnitine acetyltransferase, causing depletion of the body R-(-)-carnitine stock. Consequently, the separation of carnitine enantiomers is very important both to study their biological activities and to control the enantiomeric purity of pharmaceutical formulations. In the present paper we describe an easy, fast and convenient procedure for the separation of the enantiomers of carnitine and O-acylcarnitines by enantioselective HPLC on a laboratory-made chiral column containing covalently bonded teicoplanin as selector. High enantioselectivity factors (alpha values ranging from 1.31 to 3.02) and short-time analyses characterize the analytical procedure; in addition, analytes are easily detected by evaporative light scattering with no need for preliminary derivatization. The effects of pH and ionic strength of the mobile phase and of the nature of the organic modifier on the enantioselective separations were also investigated.

Reversible Carnitine Palmitoyltransferase Inhibitors with Broad Chemical Diversity as Potential Antidiabetic Agents

A series of carnitine related compounds of general formula XCH(2)CHZRCH(2)Y were evaluated as CPT I inhibitors in intact rat liver (L-CPT I) and heart mitochondria (M-CPT I). Derivative 27 (ZR = -HNSO(2)R, R = C(12), X = trimethylammonium, Y = carboxylate, (R) form) showed the highest activity (IC(50) = 0.7 microM) along with a good selectivity (M-CPT I/L-CPTI IC(50) ratio = 4.86). Diabetic db/db mice treated orally with 27 showed a significant reduction of serum glucose levels.

Determination of aliphatic amines by gas and high-performance liquid chromatography

Abstract Aliphatic amines, such as mono-, di- and trimethylamine (MMA, DMA, TMA) and trimethylamine N-oxide (TMAO), are produced by bacterial degradation of trimethylalkylammonium compounds, such as choline, acetylcholine, carnitine and γ-betaines. This degradation can be environmental, intestinal or faecal1.2. This paper describes an analytical investigation by gas chromatography (GC) with flame ionization detection (FID) or thermionic specific detection (TSD) and by high-performance liquid chromatography (HPLC) with conductimetric, refractive index (RI) and electrochemical detection (ED) for the simultaneous determination of the above amines, mainly applied to biological samples such as urine, and an assay procedure adopted consisting in chemical reduction of TMAO to TMA, followed by evaluation of the latter by GC in order to determine the TMAO.