Ladislas Colarow

Characterization and biological activity of gangliosides in buffalo milk.

Gangliosides (GS) were evaluated in Swiss cows milk (SCM), Italian buffalo milk (IBM) and its serum, Pakistan buffalo colostrum (PBC), Pakistan buffalo mature milk (PBM), and Pakistan buffalo milk from rice-growing areas (PBR). Dairy GS were obtained from the Folchs upper (hydrophilic) and lower (lipophilic) extraction phases, respectively, and determined as lipid-bound sialic acid (LBSA) by colorimetry. Molar ratios of LBSA in the hydro- and lipophilic GS fractions were 52:48 to 79:21. Mature buffalo milk types had 40-100% more LBSA in the lipophilic GS fraction compared to SCM. Liquid PBC was higher in LBSA (24 nmol/g) compared to mature milk types (8-11 nmol/g). Thin-layer chromatography (TLC) and scanning densitometry showed distinct profiles of hydrophilic and lipophilic GS fractions. Lipophilic GS (but importantly not hydrophilic GS) from IBM and its serum decreased prostaglandin series 2 production by 75-80% in cultured human colonic epithelial cells exposed to tumor necrosis factor alpha (TNFalpha). Hydrophilic GD(3) and lipophilic GM(3) selectively bound rotavirus particles prepared from a rhesus strain and its mutant. A GS fraction in IBM showed a GM(1)-specific binding to cholera toxin subunit B (CTB). IBM serum (IBMS) was a rich source of LBSA (420 nmol/g proteins). In summary, improved methodology led to increased LBSA recovery and isolation of additional and bioactive milk GS. Human and Italian buffalo milk had similar CTB binding, and both had increased polysialo-GS compared to cows milk. The toxin binding properties of buffalo milk GS, and the anti-inflammatory activity of the lipophilized GS fraction could be important for developing innovative food applications, as well as the subject of future research.

Fractionation of Total Lipid Extracts of Animal Origin

Total lipid classes with distinctively different functional properties are usually represented by neutral lipids (NL), complex lipids (CL), phospholipids (PL), glycolipids (GL), gangliosides (GS) and ceramidehexosides plus sulfatides (CS). The classes are required individually or in a particular combination as micronutrients and liposomal agents for the formulation of advanced health products or cosmetic formulas. Their isolation from total lipid extracts of animal origin is possible using three different procedures, which are described below (2). These procedures are suitable for industrial as well as analytical applications. Efficiency of the whole process is demonstrated by fractionation of the total lipids extracted from bovine brain, cerebrospinal fluid, lungs, pancreas and delactosed buttermilk. The resulting lipid fractions are evaluated by planar chromatography (HPTLC) whereas the composition of O-acyl (phosphoglycerides) and N-acyl (sphingomyelin and glycolipids) moieties is analyzed by capillary gas-chromatography (GC) after an acetyl chloride-catalyzed derivatization (5). The methylation reaction is equally efficient for phospholipids and their plasmalogens, thus producing both the fatty acid methyl esters and dimethylacetals.