Bile acids extraction

Purification of bile acids extracted from human stool quantitation by GC/FID 75... 

Bile acids are recycled via the enterohepatic circulation, with less than 5% of the total bile acid pool entering the colon.Bile adds are reabsorbed by ileum columnar epithelium cells and are transported back to the liver by the portal vein where they are extracted by hepatocytes. Approximately 6-12 enterohepatic circulations occur daily. Free bile acids, like DCA, are partly absorbed into the colon and enter the enterohepatic circulation, where they are... 

The statins, lovastatin (L), simvastatin (S), pravastatin (P), fluvastatin (F), cerivastatin, and atorvastatin, inhibit HMG CoA reductase. The active group of L, S, P, and F (or their metabolites) resembles that of the physiological substrate of the enzyme (A). L and S are lactones that are rapidly absorbed by the enteral route, subjected to extensive first-pass extraction in the liver, and there hydrolyzed into active metabolites. P and F represent the active form and, as acids, are actively transported by a specific anion carrier that moves bile acids from blood into liver and also mediates the selective hepatic uptake of the mycotoxin, amanitin (A), Atorvastatin has the longest duration of action. 

Bile. The liver forms a thin secretion (bile) that is stored in the gallbladder after water and salts have been extracted from it. From the gallbladder, it is released into the duodenum. The most important constituents of bile are water and inorganic salts, bile acids and bile salts (see p. 314), phospholipids, bile pigments, and cholesterol. Bile salts, together with phospholipids, emulsify insoluble food lipids and activate the lipases. Without bile, fats would be inadequately cleaved, if at all, resulting in fatty stool (steatorrhea). Resorption of fat-soluble vitamins would also be affected. 

Hemagglutinin activity. Saline extract of the dried seed, at a concentration of 10%, was active on the human red blood cells L Hypocholestrolemic activity. Fresh root, taken orally by human adults at a dose of 200 g/person, was active. Daily ingestion at breakfast for 3 weeks decreased cholesterol in serum by 11%, increased fecal bile acid and fat excretion by 50%, and increased stool weight by 25%° . 

Qureshi MY, Smith SM, Murphy GM (1984) Colorimetric enzymatic measurement of serum total -hydroxy bile acid concentrations without extraction. Clin Pathol 37 317-320... 

Raw Materials and Extraction. The variety of natural sources of steroid raw materials is vast, and the exact details of manufacturing processes are ambiguous closely held industrial secrets. However, the most widely utilized raw materials for die partial synthesis of steroids appear to be the following (/) the sapogenins, for example, diosgenin (27). (2) the sir-ucliirally relaied sierold alkaloids, (3) sterols, such as cholesterol (8), and (4) bile acids. 

Stark, A. and Madar, Z. 1993. The effect of an ethanol extract derived from fenugreek (Trigo-nella foenum-graecum) on bile acid absorption and cholesterol levels in rats. Br. J. Nutr. 69, 277-287. 

Cool to room temperature, add 10 ml hexane or petroleum ether, tighten caps, and shake vigorously for 15 sec. Centrifuge at 1000 7 for 10 min to separate phases and remove the organic layer (top) to a fresh tube or scintillation vial. Repeat the extraction twice and combine organic layers. Save the aqueous layer (bottom) in the original tube for bile acid analysis. 

In the ASAHI KASEI Medical (Tokyo, Japan) system, the plasmapheresis step is performed by a microporous membrane (Plasmaflo) made of a copolymer of ethylene and vinyl alcohol (PEVA), with a maximum pore size of0.3 pm. The extracted plasma flows through an activated charcoal column Hemosorba and an anion-exchange column (copolymer of styrenedivinyl benzene) Plasorba that binds bilirubin and bile acids [28]. Each column contains 350 mL of adsorbent. 

Trifluoroacetates of 18 steroids were analysed by Voelter et al. [353] on OV-17, OV-1 and XE-60 stationary phases and compared with the results for TMS derivatives. On the first two stationary phases TFA derivatives have shorter retention times, whereas on XE-60 the reverse applies. With the use of the FED, TFA derivatives gave 30—50% higher responses. These derivatives were also applied to the analysis of the bile acids [354]. In order to eliminate the treatment with diazomethane, the carboxyl group of bile acids was blocked by the reaction with hexafluoroisopropanol, as follows. A 100-pl volume of hexafluoroisopropanol and 200 pi of trifluoroacetic anhydride were added to the dried extract of bile acids and the mixture was heated at 37° C for 30 min. The mixture was evaporated under reduced pressure at room temperature and the residue dissolved in 100 pi of acetonitrile 5 pi were analysed on a 2 m X3 mm I.D. column packed with 1% QF-1 on Chromorosb W (80 100 mesh). As the FID was applied, a high ECD response was not used to advantage. 

Ox Bile Extract occurs as a yellow-green powder. It contains ox bile acids, chiefly glycocholic and taurocholic, as sodium salts, equivalent to not less than 45.0% cholic acid, C24H40O5. It is the purified portion of the bile of an ox, obtained by evaporating the alcohol extract of concentrated bile. It is soluble in water and in alcohol. 

Before the advent of soft ionization techniques, the analysis of bile acids was long and tedious and needed large sample quantities. First, the bile acids had to be extracted from the biological fluid and separated by lipophilic ion exchange chromatography into four classes ... 

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