Higher Bile Acid Binding Research Articles

Extraction and Characterization of β-Glucan from Kombucha Bacterial Cellulose and Concentrated Kombucha: Evaluating their Bile Acid Binding Capacity

β-glucan is a water-soluble polysaccharide present in natural products and has many health benefi ts such as its role as a dietary fi ber. This study aimed to extract and characterize β-glucan in kombucha bacterial cellulose (KBC) powder and concentrated kombucha. The extraction method used was ultrasound sonication combined with enzymatic treatment. The results showed that the content of β-glucan was 19.70% (w/w) in KBC extract and 8.34% (w/v) in concentrated kombucha extract, determined using β-glucan assay kit (Mixed linkage). Fourier-transform infrared (FTIR) spectroscopy analysis confi rmed the presence of β-glucan with β-(1→3) and β-(1→4) glucan linkages, as well as the presence of proteins, mannans, and other components in both KBC β-glucan and concentrated kombucha β-glucan extracts. Regarding bile acid binding potential, concentrated kombucha β-glucan exhibited a high bile acid binding capacity for up to 24 hours, while KBC β-glucan only retained this capacity for up to 4 hours. Altogether, these fi ndings highlight the presence and properties of β-glucan in kombucha, suggesting its potential as a functional ingredient with health benefi ts.

Valorizing cabbage (Brassica oleracea L. var. capitata) and capsicum (Capsicum annuum L.) wastes: in vitro health-promoting activities.

The capsicum seed core and cabbage outer leaves are common wastes generated in the vegetable processing industry. We explored the in vitro health-promoting activity of these waste products for valorization. Freeze-dried and pulverized cabbage wastes had a high bile acid binding capacity and the capsicum wastes inhibited glucose dialysis more effectively. Methanolic extracts prepared with conventional solvent extraction and ultrasound-assisted extraction were analyzed to determine their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, in vitro α-amylase inhibitory, in vitro lipase inhibitory, and prebiotic activity. Crude extracts of cabbage and capsicum wastes were screened using GC-MS analysis. The cabbage waste extracts showed high antioxidant activities but did not inhibit α-amylase. The capsicum waste extracts inhibited both lipase and α-amylase activities and supported the growth of the probiotic bacterium, Lactobacilli brevis. Volatile compounds of the vegetables consisted mainly of phenols and fatty acid esters. In all assays except the α-amylase inhibition assay, the extracts prepared with ultrasound-assisted solvent extraction showed higher activity than those prepared using the conventional method. The capsicum seed core and cabbage outer leaves are potential sources of phytochemicals and antioxidant fibers. Capsicum waste extract supported probiotic bacterial growth without a lag phase. These waste products may be processed into high-value functional ingredients.

Bioassay Guided Isolation of Polysaccharide Rich Fraction from Myrmecodia Platytyrae and its Bile Acid Binder Property

Bioassay guided isolation was done on the Myrmecodia platytyrae (MyP) extracts in order to find the best extract that can bind with bile acid. The function of bile acid binder is to reduce the reabsorption of bile acid in the intestine so that it will cause the decrease of cholesterol in the blood circulation. The extraction process was started by using different organic solvent such as hexane, toluene, ethyl acetate, ethanol and water. All extracts were tested its bile acid binding properties and the extract gave out highest activity was selected to be fractionated. The result showed that water extract has highest bile acid binding property (75%). Then, fractionation process was performed in order to find the best fraction from water extract that have bile acid binding property. The sub-fractionation processes were continued and the process only focussed to the fraction that has highest bile acid binding property until a white powder with 97.02 % carbohydrate was obtained. The powder was subjected to FTIR and was found to have glycosidic bond as shown by bands at 1141 until 1018 cm-1 which is a character of polysaccharide. The polysaccharide rich fraction was hydrolysed and subjected to HPLC to identify its monosaccharide groups. The result showed the presence of glucose and fructose were found to be among the major monosaccharides. This result suggested that the polysaccharide from MyP water extract with high bile acid binding property was gluco-fructan.

In vitro effects of four polysaccharides containing β-D-Glup on intestinal function

ABSTRACTPlant polysaccharides exert a wide range of biological effects on the intestinal function. In this study, four polysaccharides containing β-D-Glup, including Dendrobium officinale polysaccharide (DOP), Dendrobium aphyllum polysaccharide (DAP), and glucans from yeast (G-Y) and barley (G-B), were investigated in vitro for their intestinal-promoting functions such as inhibition of digestive enzymes, effect of blood glucose and blood lipid levels by using ultraviolet spectrophotometry, as well as the relationship of their structures to those functions. The results indicated that all polysaccharides significantly slowed glucose diffusion rate, decreased protease, and pancreatic lipase activities. Increased branching degrees had a deleterious effect on the α-amylase activity but increased bile acid binding. Increased calcium concentration in glucans (G-Y and G-B) and increased mannose molar ratio in Dendrobium polysaccharides (DOP and DAP) were correlated with increased pancreatic lipase inhibition. The polysaccharides with higher glucose content and branching degrees had higher bile acid binding and disruption of cholesterol micelle formation. These polysaccharides exerted a variety of potential health-promoting effects attributed to their different structures, which should be further investigated in vivo.

A Review – In Vitro Bile Acid Binding of Various Vegetables

Health promoting potential (cholesterol lowering and cancer risk reduction) of various vegetables could be determined by evaluating their bile acid binding capacity. Bile acid binding of sixteen vegetable raw (uncooked), steamed, sauteed, microwave, microwave with water and boiled were reported in six studies. Highest bile acid binding values were observed with steaming and boiling resulted in lowest values. The Steamed vegetable would retain most of the phytonutrients. By steaming observed bile acid bindings were for Turnips 1.2%, Green Bell Pepper and Cabbage 4%, Cauliflower, Green Beans, Carrots, Spinach, Brussels Sprouts and Broccoli 6-8%, Asparagus, Collard Greens, Mustard Greens and Kale 10-13%, Eggplant 14%, Okra 16% and Beets 18%. Various vegetables when consumed regularly after steam cooking, combined with low fat diet would result in potential lower risk of premature degenerative diseases (heart disease and cancer), improve public health and advance human nutrition research.

Dietary ε-Polylysine Decreased Serum and Liver Lipid Contents by Enhancing Fecal Lipid Excretion Irrespective of Increased Hepatic Fatty Acid Biosynthesis-Related Enzymes Activities in Rats

ɛ-Polylysine (EPL) is used as a natural preservative in food. However, few studies have been conducted to assess the beneficial functions of dietary EPL. The purpose of this study was to elucidate the mechanism underlying the inhibition of neutral and acidic sterol absorption and hepatic enzyme activity-related fatty acid biosynthesis following EPL intake. EPL digest prepared using an in vitro digestion model had lower lipase activity and micellar lipid solubility and higher bile acid binding capacity than casein digest. Male Wistar rats were fed an AIN-93G diet containing 1% (wt/wt) EPL or l-lysine. After 4 weeks of feeding these diets, the marked decrease in serum and liver triacylglycerol contents by the EPL diet was partly attributed to increased fecal fatty acid excretion. The activities of hepatic acetyl-coenzyme A carboxylase and glucose-6-phosphate dehydrogenase, which are key enzymes of fatty acid biosynthesis, were enhanced in rats fed EPL diet. The increased fatty acid biosynthesis activity due to dietary EPL may be prevented by the enhancement of fecal fatty acid excretion. The hypocholesterolemic effect of EPL was mediated by increased fecal neutral and acidic sterol excretions due to the EPL digest suppressing micellar lipid solubility and high bile acid binding capacity. These results show that dietary EPL has beneficial effects that could help prevent lifestyle-related diseases such as hyperlipidemia and atherosclerosis.

In Vitro Binding Capacity of Bile Acids by Defatted Corn Protein Hydrolysate

Defatted corn protein was digested using five different proteases, Alcalase, Trypsin, Neutrase, Protamex and Flavourzyme, in order to produce bile acid binding peptides. Bile acid binding capacity was analyzed in vitro using peptides from different proteases of defatted corn hydrolysate. Some crystalline bile acids like sodium glycocholate, sodium cholate and sodium deoxycholate were individually tested using HPLC to see which enzymes can release more peptides with high bile acid binding capacity. Peptides from Flavourzyme defatted corn hydrolysate exhibited significantly (p < 0.05) stronger bile acid binding capacity than all others hydrolysates tested and all crystalline bile acids tested were highly bound by cholestyramine, a positive control well known as a cholesterol-reducing agent. The bile acid binding capacity of Flavourzyme hydrolysate was almost preserved after gastrointestinal proteases digestion. The molecular weight of Flavourzyme hydrolysate was determined and most of the peptides were found between 500-180 Da. The results showed that Flavourzyme hydrolysate may be used as a potential cholesterol-reducing agent.

In vitro binding of bile acids by soy protein, pinto beans, black beans and wheat gluten

The in vitro bile acid binding by soy protein, pinto beans, black beans and wheat gluten was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing substrates on an equal protein basis. Considering cholestyramine as 100 bound, the relative in vitro bile acid bindings for the soy protein, pinto beans, black beans and wheat gluten, on equal protein basis, were 17, 23, 30 and 12%, respectively. Bile acid binding by soy protein, pinto beans and black beans may influence cholesterol lowering, lipid and lipoprotein metabolism, and reduction of plaque formation in the aortic arch. Higher bile acid binding by black beans and pinto beans than soy protein is encouraging; it suggests that there may be components, other than the bean protein, with the desired health-promoting properties. As for wheat gluten, bile acid binding may relate to its potential for improving gastrointestinal health and reduction of the risk of cancer. These results point to bile acid binding by soy protein, pinto beans, black beans and wheat gluten as indicative of their health-promoting potential.

Hypocholesterolemic effect of indigestible fraction of Chlorella regularis in cholesterol-fed rats.

The effects of Chlorella regularis powder (CP) and Chlorella regularis indigestible fraction (CIF) on serum and liver lipid concentrations and on fecal steroid excretion were estimated in rats fed diets containing 5 g/kg cholesterol and 2.5 g/kg sodium cholate. The ingestion of 12.7% CP or 5.3% CIF did not influence food intake or growth. CP and CIF decreased the levels of serum cholesterol, but had no effect on the levels of serum triacylglycerol and phospholipid. Liver cholesterol contents were lower in the CP and CIF groups than in the control group, but CP and CIF did not affect liver triacylglycerol content. CP and CIF increased the total amount of fecal neutral steroids excreted, but did not modify the total bile acid excretion. However, the soluble bile acid concentrations of reconstituted fecal water in the rats fed CP and CIF diets were lower than the control value. Moreover, CP and CIF had a high bile acid binding capacity in vitro. These results indicated that CIF had a hypocholesterolemic effect and enhanced fecal neutral steroid excretion while decreasing the soluble fecal bile acid concentration.

Plasma cholesterol reduction by defatted soy ontjom (fermented with Neurospora intermedia) in rats fed a cholesterol-free diet.

To popularize defatted soy ontjom (DSB-ontjom, soy product fermented with Neurospora intermedia) as a new food, I examined the plasma cholesterol-reducing effects of DSB-ontjom and DSB in rats fed cholesterol-free diets and compared the efficiencies of these effects. DSB-ontjom greatly reduced the plasma cholesterol level and increased fecal steroid excretion as compared to DSB. DSB-ontjom was rich in pepsin-resistant protein having a high bile acid binding capacity and was abundant in isoflavone-aglycones, especially daizein. The dietary fiber (DF) of DSB-ontjom stimulated the production of short-chain fatty acids (SCFAs) by intestinal microflora. The effect of DSB-ontjom on plasma cholesterol reduction was attributed to the collaborative effects of pepsin-resistant-protein, isoflavone-aglycones and SCFA-producing DF in DSB-ontjom.

Genomic organization and chromosomal localization of a novel human hepatic dihydrodiol dehydrogenase with high affinity bile acid binding.

We previously characterized and cloned a unique human hepatic dihydrodiol dehydrogenase (DDH) that exhibits high affinity binding for bile acids (Stolz, A., Hammond, L., Lou, H., Takikawa, H., Ronk, M., and Shively, J. E. (1993) J. Biol. Chem. 268, 10448-10457). This hepatic dihydrodiol dehydrogenase demonstrates significant sequence homology with the cytosolic rat bile acid binder 3 alpha-hydroxysteroid dehydrogenase and other members of the monomeric oxidoreductase gene family. We now report the genomic organization and chromosomal localization of the human hepatic DDH in order to further define its physiological role and provide additional insight into the development of this gene family. The 15-kilobase human hepatic DDH gene was contained in an overlapping cosmid and lambda genomic clones and is composed of nine exons. A major transcriptional start site was determined to be 30 base pairs upstream from the ATG initiation methionine by both primer extension and S1 nuclease mapping studies. The human hepatic DDH gene was mapped by chromosomal in situ hybridization and analysis of human-mouse somatic cell hybrids to the tip of the short arm of chromosome 10 at p14. Strict conservation of the intron-exon junctions in the human hepatic DDH and two other members of the monomeric oxidoreductase gene family, aldose reductase and mouse major vas deferens protein suggests evolution from a common ancestral gene. Human hepatic DDH mRNA was identified in both human hepatoma Hep G2 and human lung carcinoma cell line NCI-H322 by RN'ase protection; thus, these cell lines will be useful in examining the regulation of the gene.

CDNA cloning and expression of the human hepatic bile acid-binding protein. A member of the monomeric reductase gene family

In human liver, we previously identified one isoform of dihydrodiol dehydrogenase activity that expresses high affinity bile acid binding (HBAB) with minimal 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) activity for bile acids. This protein may assist in the rapid intracellular transport of bile acids from the sinusoidal to the canalicular pole of the cell. We now report the cDNA cloning and bacterial expression of this novel, multifunctional protein. A 1252-base pair HBAB cDNA was cloned from a HepG2 lambda GT11 library using a rat hepatic bile acid binder cDNA probe. Bacterial expressed recombinant HBAB oxidized racemic trans dihydrodiol benzene (0.455 mumol NADPH/mg/min) with minimal 3 alpha-HSD activity for bile acids (< 0.003 mumol NADPH/mg/min). Lithocholic acid and chenodeoxycholic acid dissociation constants as determined by displacement of the fluorescent probe, bis-1-anilino-8 sulfonate, were higher than those previously reported for the native protein (1 microM versus 10 nM). Significant amino acid sequence homology was found with the human chlordecone reductase, bovine prostaglandin F synthetase, and rat hepatic-3 alpha-HSD suggesting, that HBAB is also a member of the recently identified, monomeric oxidoreductase gene family. Future studies will define the physiologic significance of this novel, multifunctional protein in bile acid transport and xenobiotic metabolism.