ABSTRACT
@#Palm olein (POo) has been perceived as atherogenic due to its high proportion of palmitic acid (41.2%) content. It is interesting that most of the palmitic acid of POo is located at stereospecific numbering sn-1 and sn-3 positions of the triacylglycerol (TAG) backbone. The present study aims to investigate the effects of positional distribution of fatty acids on the lipid profiles of POo or chemically interesterified palm olein (CIE POo) fed hamsters in comparison to high oleic sunflower oil (HOSO) fed hamsters. Male weanling Syrian golden hamsters (n=10 for each group), were fed diets formulated with the above oils for 12 weeks. There was no significant difference between CIE POo and HOSO groups for total cholesterol (TC). CIE POo with increased amount of palmitic acid (43.2%) at sn-2 position did not cause significant increases in TC levels compared to the HOSO group. In addition, the POo group has significantly higher high-density lipoprotein cholesterol (HDL-C) than that of the HOSO group, P = 0.011 (< 0.05) while the HOSO group has significantly lower total cholesterol (TC) levels than that of the POo group, P = 0.012 (< 0.05).
ABSTRACT
Aims: This study describes the transformation of cholic acid to hydroxylated cholic acid metabolites that could not be easily synthesized. Study Design: The transformation was catalyzed by thermophilic Geobacillus stearothermophilus comb. nov., isolated from oil contaminated soil in Kuwait. Cholic acid, as the sole source of carbon, was added to G. stearothermophilus cells in phosphate buffer pH 7 and shaken at 65ºC for 5 days. Methodology: The cholic acid transformation products were extracted with ethyl acetate, purified on preparative TLC plates and their molecular structures were established from their spectral data. Results: The bacterium could selectively oxidize hydroxyl-groups at C3 and C7 while leaving the C12-hydroxyl-group unoxidized, in cholic acid. Five commonly found metabolites of cholic acid and a novel transformation product, 16α-hydroxycholic acid, were identified. Conclusion: Our results indicate that G. stearothermophilus can hydroxylate/oxidize a steroid nucleus at various ring positions, and has a unique ability for hydroxylation at C16α in cholic acid.