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Thin-Layer Chromatography in Clinical Chemistry
Published in Bernard Fried, Joseph Sherma, Practical Thin-Layer Chromatography, 2017
Bile acids are 24-carbon steroid derivatives. They are formed by the conversion of cholesterol to cholic and chenodeoxy cholic acids (primary bile acids). These are then conjugated with glycine or taurine via amide linkage in the liver. After conjugation they are eliminated together with the bile. Most of the bile acids entering the gut are reabsorbed in the terminal ileum, while some of them undergo bacterial deconjugation. In this process, secondary bile acids (deoxy cholic, lithocholic, and ursodeoxycholic acids) and a number of keto-bile acids occurring in feces are formed. The investigation of bile acids has clinical importance in the diagnosis of certain liver or intestinal disorders. In biomedicine, concentrations of bile acids in human feces are used for diagnosis of bile acid malabsorption and chologenic diarrhea. In liver disorders, serum levels of bile acids are elevated and their measurement is a sensitive index of liver disease. Bile acids are not found in urine owing to efficient uptake by the liver and excretion into the intestine. In hepatocellular disease and obstructive jaundice, however, their urinary excretion increases.
Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1
Published in Preparative Biochemistry & Biotechnology, 2023
Di Xue, Fangyi Pei, Henan Liu, Zhenyan Liu, Yuchao Liu, Lei Qin, Yinzhuo Xie, Changli Wang
Bile acid binding in vitro was analyzed via the reported method, with modifications.[37–40] In brief, 1 mL of SPZ at different concentrations (0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 mg/mL) was combined with 1 mL of HCl (0.01 mol/L) and 3 mL of pepsin (10 mg/mL), respectively, and the reaction was performed at 120 rpm at 37 °C for 1 h. NaOH (0.1 mol/L) was used to adjust the pH to 6.3, and 4 mL of trypsin (10 mg/mL) was added at 37 °C and 120 rpm for 1 h. In total, 4 mL each of cholic acid (CA, 0.5 mg/mL), taurochenocholic acid (TA, 0.5 mg/mL) and glycocholic acid (GA, 0.5 mg/mL) were added to the reaction system, respectively. Subsequently, the reaction was performed at 120 rpm at 37 °C for 1 h. After centrifugation at 4000 rpm for 20 min, 1 mL of supernatant was taken and 3 mL of 60% sulfuric acid (v/v) was added to the reaction system at 70 °C for 20 min, before being placed in an ice bath for 5 min. The absorbance was measured at 387 nm using a microplate reader, with phosphate buffer without bile acid used as the blank. The ability of bile acid binding was calculated according to the formula: where C1 is the initial concentration of cholate solution, and C2 is the residual concentration of the cholate solution.
Process optimization in ginseng fermentation by Monascus ruber and study on bile acid-binding ability of fermentation products in vitro
Published in Preparative Biochemistry & Biotechnology, 2021
Chongyan Zhao, Fang Yang, Feng Lin, Qingsong Qu, Zhixun Li, Xing Liu, Lu Han, Xinyuan Shi
Cholesterol is a precursor to the synthesis of bile acids. About 80% of the cholesterol is metabolized by liver tissue and converted to bile acid, which is involved in the enterohepatic circulation. Finally, part of bile acid is reabsorbed by the body.[36,37] de Aguiar Vallim[38] reported that bile acids can bind some food ingredients and then excrete with the digestion of food. Therefore, Cholesterol will be continuously converted to bile acids to maintain the homeostasis of the bile acid pool, thereby reducing the cholesterol content in the blood. In the human body, bile acids are classified into free bile acids (cholic acid, deoxycholic acid, etc.) and conjugated bile acid (cholic acid, deoxycholic acid, etc. combined with glycine and taurine).[39] The conjugated bile acids are generally present in the form of sodium salts, which is more common in the human body. Therefore, in this study, it is applicable that sodium taurocholate and sodium cholate were selected as representative of the conjugated bile acids.
Mesomorphic properties of fluorinated cholesteric three-arm liquid crystals based on chenodeoxycholic acid
Published in Liquid Crystals, 2020
Chiral liquid crystals (LCs) include chiral smectic LCs, blue phase LCs and cholesteric LCs (or chiral nematic LCs). Cholesteric LCs were studied because of their special properties, which are the selective reflection of light, thermochromism, ferroelectricity and circular dichroism, etc [1–11]. Cholesteric LCs were applied in optical and electrical materials [12–19] and biological materials [20]. Fluorinated materials play an important role in various applications such as electronics, electro-optic. Fluorine substituent has small size, high polarity, high stability, dielectric anisotropy and the appropriate dielectric constant properties. The introduction of fluorine substituent has enriched many basic physical properties of LCs [21–32] including dielectric properties [21–28], optical properties [22,29] and electro-optical performance [30,31]. Multi-arm LCs are composed of a core and several mesogenic units. In recent years, multi-arm LCs have been frequently synthesised based on cholic acid [33–36], chenodeoxycholic acid [37,38] and other cores [39–42]. Some of these [33–38] may also be classified as LC oligomerics [43–48]. In addition, some researches about multi-arm ionic LCs have been reported [49]. For multi-arm LCs, chiral cores are able to induce the multi-arm LCs with nematic and smectic side arms to display cholesteric phase [38,50,51].