Design and optimization of cranberry extract loaded bile salt augmented liposomes for targeting of MCP-1/STAT3/VEGF signaling pathway in DMN-intoxicated liver in rats.

Cranberry extract (CBE) is a major source of the antioxidant polyphenolics but suffers from limited bioavailability. The goal of this research was to encapsulate the nutraceutical (CBE), into bile salt augmented liposomes (BSALs) as a promising oral delivery system to potentiate its hepatoprotective impact against dimethylnitrosamine (DMN) induced liver injury in rats. The inclusion of bile salt in the liposomal structure can enhance their stability within the gastrointestinal tract and promote CBE permeability. CBE loaded BSALs formulations were fabricated utilizing a (23) factorial design to explore the impact of phospholipid type (X1), phospholipid amount (X2), and sodium glycocholate (SGC) amount (X3) on BSALs properties, namely; entrapment efficiency percent, (EE%); vesicle size, (VS); polydispersity index; (PDI); zeta potential, (ZP); and release efficiency percent, (RE%). The optimum formulation (F1) exhibited spherical vesicles with EE% of 71.27 ± 0.32%, VS; 148.60 ± 6.46 nm, PDI; 0.38 ± 0.02, ZP; -18.27 ± 0.67 mV and RE%; 61.96 ± 1.07%. Compared to CBE solution, F1 had attenuated DMN-induced hepatic injury, as evidenced by the significant decrease in serum level of ALT, AST, ALP, MDA, and elevation of GSH level, as well as SOD and GPX activities. Furthermore, F1 exhibited an anti-inflammatory character by suppressing TNF-α, MCP-1, and IL-6, as well as downregulation of VEGF-C, STAT-3, and IFN-γ mRNA levels. This study verified that when CBE was integrated into BSALs, F1, its hepatoprotective effect was significantly potentiated to protect the liver against DMN-induced damage. Therefore, F1 could be deliberated as an antioxidant, antiproliferative, and antifibrotic therapy to slow down the progression of hepatic damage.

The characterization and biological activities of synthetic N, O-selenized chitosan derivatives.

Synthetic selenium polysaccharides with potential bioactivity have drawn great interest due to the SeO bonds existing in the structure. Herein, N, O-selenized N-(2-carboxyethyl) chitosan (sNCCS) was synthesized through carboxyethylation and selenylation. Various characterizations were performed to identify the structure of sNCCS, indicating that SeO bonds were formed both at the C-6 hydroxyl groups and the introduced C-2 carboxyethyl groups. The highest yield and selenium content of all sNCCS reached 84.5% and 1.553 mg/g, respectively. In vitro evaluation exhibited that sNCCS has excellent bile acid binding capacity, which was 1.63, 2.00, and 2.55-fold higher than that of N-(2-carboxyethyl) chitosan (NCCS). Moreover, it was found that higher selenium content could significantly enhance the antioxidant properties of sNCCS. Importantly, no obvious cytotoxic effect had been observed on Caco-2 cells. Taken together, sNCCS with desirable biological activity and non-cytotoxicity might be considered as an effective ingredient in the fields of food or medicine.

Da-Huang-Xiao-Shi decoction protects against3, 5-diethoxycarbonyl-1,4-dihydroxychollidine-induced chronic cholestasis by upregulating bile acid metabolic enzymes and efflux transporters.

ETHNOPHARMACOLOGICAL RELEVANCE: Chronic cholestasis is a usual clinical pathological process in hepatopathy and has few treatment options; it is classified under the category of jaundice in Chinese medicine. Da-Huang-Xiao-Shi decoction (DHXSD) is a classic Chinese prescription which is used to treat jaundice. AIM OF THE STUDY: We aimed to examine the protective effect of DHXSD on liver and its potential mechanism of action against chronic cholestasis. MATERIALS AND METHODS: Chronic cholestasis was induced using 3, 5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) in mice. Mice were then administered DHXSD intragastrically at doses of 3.68, 7.35, and 14.70 g/kg for four weeks followed by further analyses. Serum biochemical indices and liver pathology were explored. Eighteen individual bile acids (BAs) in mice serum and liver were quantified using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The expression of BA related metabolic enzymes, transporters, along with nuclear receptor farnesoid X receptor (FXR) was detected by real-time qPCR and Western blot. RESULTS: DHXSD treatment reduced the serum biochemical indices, ameliorated pathological injury, and improved the disordered BA homeostasis. Mice treated with DHXSD showed significantly upregulated expression of the metabolic enzymes, cytochrome P450 2b10 (Cyp2b10), Cyp3a11, and UDP-glucuronosyltransferase 1a1 (Ugt1a1); and the bile acid transporters, multidrug resistance protein 2 (Mdr2), bile salt export pump (Bsep), and multidrug resistance-associated protein 3 (Mrp3). DHXSD treatment also significantly upregulated FXR expression in mice with DDC-induced chronic cholestasis. CONCLUSIONS: DHXSD exerted protective effects on chronic cholestasis in DDC-treated mice by alleviating the disordered homeostasis of BAs through increased expression of BA related metabolic enzymes and efflux transporters.

Process optimization in ginseng fermentation by Monascus ruber and study on bile acid-binding ability of fermentation products in vitro.

Ginseng (Panax ginseng C. A. Meyer) is a famous Traditional Chinese Medicine, which is widely used to treat cardiovascular disease. Monascus ruber (M. ruber) is a fungus used in food and medicine fermentation, and lovastatin, its metabolite, is used extensively in the treatment of dyslipidemia. In this study, ginseng has been fermented by M. ruber, and the response surface methodology (RSM) was applied to optimize fermentation parameters to obtain optimal fermentation system, with further exploring to lipid-lowering activity of P. ginseng C. A. Meyer-M. ruber fermentation products (PM). The concentration of ginseng, temperature, and rotating speed were set as variables and the lovastatin yield was optimized by a Box-Behnken design (BBD) analyzed by RSM. The binding capacity of PM for sodium taurocholate and sodium cholate was assayed by UV spectrophotometry. The highest content of lovastatin production (85.53 µg g-1) was obtained at a ginseng concentration of 1.96%, temperature of 30.11 °C, and a rotating speed of 160.47 rpm. PM exhibited bile acid binding capacity, which was stronger than unfermented ginseng. The RSM can be used to optimize the fermentation system to obtain the best fermentation process. In addition, the fermentation of ginseng by M. ruber can enhance the lipid-lowering effect.

Vitamin D Receptor Deletion Changes Bile Acid Composition in Mice Orally Administered Chenodeoxycholic Acid.

The vitamin D receptor (VDR) is a nuclear receptor for the active form of vitamin D3 and also for the secondary bile acid lithocholic acid (LCA). The in vivo role of VDR in bile acid metabolism remains largely uncharacterized. We previously reported that pharmacological VDR activation enhances urinary bile acid excretion, particularly in mice fed chow supplemented with chenodeoxycholic acid (CDCA), which is metabolized to muricholic acid in mouse liver and is also converted to LCA by intestinal bacteria. In this study, we examined the effect of VDR deletion on bile acid composition utilizing VDR-knockout (VDR-KO) mice. VDR deletion did not change total bile acid levels in liver or feces of mice when fed standard chow supplemented with calcium, needed to prevent hypocalcemia in VDR-KO mice. Total bile acid levels in plasma and urine tended to be higher and lower, respectively, in VDR-KO mice. After feeding CDCA-supplemented chow, VDR-KO mice showed decreased hepatic, fecal and urinary total bile acid and CDCA levels compared to wild-type mice. Plasma total bile acids and LCA were relatively high in these mice. These results indicate that VDR deletion influences CDCA metabolism. VDR may play a role in the excretion of excess bile acids.

Metabolite profiling reveals the interaction of chitin-glucan with the gut microbiota.

Dietary fibers are considered beneficial nutrients for health. Current data suggest that their interaction with the gut microbiota largely contributes to their physiological effects. In this context, chitin-glucan (CG) improves metabolic disorders associated with obesity in mice, but its effect on gut microbiota has never been evaluated in humans. This study explores the effect of a 3-week intervention with CG supplementation in healthy individuals on gut microbiota composition and bacterial metabolites. CG was given to healthy volunteers (n = 15) for three weeks as a supplement (4.5 g/day). Food diary, visual analog and Bristol stool form scales and a "quality of life" survey were analyzed. Among gut microbiota-derived metabolites, bile acids (BA), long- and short-chain fatty acids (LCFA, SCFA) profiling were assessed in stool samples. The gut microbiota (primary outcome) was analyzed by Illumina sequencing. A 3-week supplementation with CG is well tolerated in healthy humans. CG induces specific changes in the gut microbiota composition, with Eubacterium, Dorea and Roseburia genera showing the strongest regulation. In addition, CG increased bacterial metabolites in feces including butyric, iso-valeric, caproic and vaccenic acids. No major changes were observed for the fecal BA profile following CG intervention. In summary, our work reveals new potential bacterial genera and gut microbiota-derived metabolites characterizing the interaction between an insoluble dietary fiber -CG- and the gut microbiota.

Roasting carob flour decreases the capacity to bind glycoconjugates of bile acids.

Carob is the fruit obtained from Ceratonia siliqua L. and it is a source of bioactive compounds that have been linked to several health promoting effects, including lowering blood cholesterol concentration. The objective of this study was to connect the physicochemical changes of carob flour occurring during roasting with its capacity to bind glycoconjugates of bile acids. Carob flour samples were roasted for different times at 150 °C and chemically characterized by measuring the concentrations of tannins and polyphenols. Data showed that carob flour binds high amounts of bile acids: 732.6 µmol of bound bile acid per g of carob flour which is comparable to the 836.2 µmol per g bound by cholestyramine, a known cholesterol lowering drug. The carob flour ability to bind cholesterol decreases up to 40% during roasting. Data suggested that tannins and insoluble components play a major role in binding bile salts, as a result of hydrophobic interactions.

Development and evaluation of a biorelevant medium simulating porcine gastrointestinal fluids.

Simulated human intestinal media, have proved to be a useful biopharmaceutics tool as a dissolution media for predicting in vivo dissolution and pharmacokinetic profile in humans. During drug product development preclinical animal models are also required to assess drug product performance, and there is a need to develop species specific intestinal media to similarly predict in vivo pharmacokinetic profiles in each preclinical model. Pigs, are increasingly being used in preclinical drug development, however to date there is a lack of quantitative information about the composition of porcine gastrointestinal (GI) fluids. As a result, a porcine biorelevant medium has not yet been developed, which is essential to improve interpretation and forecast of preclinical results using biorelevant in vitro dissolution studies. GI fluid samples, were collected from landrace pigs, and characterized. Fasted State Simulated Intestinal Fluid of pigs (FaSSIFp) was developed based on the physiological composition of the GI fluids in terms of pH, buffer capacity, osmolality, surface tension, as well as the bile salt, phospholipid and free fatty acid content. This study demonstrated that FaSSIFp was superior at predicting the solubility of the six model drugs in porcine intestinal fluids (PIF). A markedly high correlation (r2 0.98) was observed between the solubility obtained in PIF and FaSSIFp, whereas poor correlation (r2 0.12) was found for the solubility of the model drugs between human FaSSIF and PIF. This confirms that species specific biorelevant intestinal media are crucial to provide more accurate predictions of pharmacokinetic studies in preclinical models. Additionally, the availability of a species specific intestinal medium offers the potential to improve in vitro-in silico approaches to predict in vivo absorption and to reduce the overall number of animals needed in oral drug product development testing.

Species Differences of Bile Acid Redox Metabolism: Tertiary Oxidation of Deoxycholate is Conserved in Preclinical Animals.

It was recently disclosed that CYP3A is responsible for the tertiary stereoselective oxidations of deoxycholic acid (DCA), which becomes a continuum mechanism of the host-gut microbial cometabolism of bile acids (BAs) in humans. This work aims to investigate the species differences of BA redox metabolism and clarify whether the tertiary metabolism of DCA is a conserved pathway in preclinical animals. With quantitative determination of the total unconjugated BAs in urine and fecal samples of humans, dogs, rats, and mice, it was confirmed that the tertiary oxidized metabolites of DCA were found in all tested animals, whereas DCA and its oxidized metabolites disappeared in germ-free mice. The in vitro metabolism data of DCA and the other unconjugated BAs in liver microsomes of humans, monkeys, dogs, rats, and mice showed consistencies with the BA-profiling data, confirming that the tertiary oxidation of DCA is a conserved pathway. In liver microsomes of all tested animals, however, the oxidation activities toward DCA were far below the murine-specific 6ß-oxidation activities toward chenodeoxycholic acid (CDCA), ursodeoxycholic acid, and lithocholic acid (LCA), and 7-oxidation activities toward murideoxycholic acid and hyodeoxycholic acid came from the 6-hydroxylation of LCA. These findings provided further explanations for why murine animals have significantly enhanced downstream metabolism of CDCA compared with humans. In conclusion, the species differences of BA redox metabolism disclosed in this work will be useful for the interspecies extrapolation of BA biology and toxicology in translational researches. SIGNIFICANCE STATEMENT: It is important to understand the species differences of bile acid metabolism when deciphering biological and hepatotoxicology findings from preclinical studies. However, the species differences of tertiary bile acids are poorly understood compared with primary and secondary bile acids. This work confirms that the tertiary oxidation of deoxycholic acid is conserved among preclinical animals and provides deeper understanding of how and why the downstream metabolism of chenodeoxycholic acid dominates that of cholic acid in murine animals compared with humans.

Structurally different mixed linkage ß-glucan supplements differentially increase secondary bile acid excretion in hypercholesterolaemic rat faeces.

Mixed linkage (1→3),(1→4)-ß-d-glucan (BG) is a soluble fibre available from oat and barley grains that has been gaining interest due to its health-promoting role in cardiovascular diseases and its ability to modulate the glycaemic index which is beneficial for people with diabetes. This study investigates the effect of three purified barley BGs, with different molecular weight and block structure, on faecal bile acid excretion in hypercholesterolaemic rats. Wistar rats (48 male) were divided in four groups: Control group fed with the cellulose-rich diet (CON); Glucagel group fed with the commercial BG (GLU, 100 kDa), and rats fed with low molecular weight BG (LBG, 150 kDa) and medium molecular weight BG (MBG, 530 kDa). The bile acid profiles of rat faecal samples were measured using gas chromatography-mass spectrometry (GC-MS). A metabolite profiling approach led to the identification of 7 bile acids and 45 other compounds such as sterols, fatty acids and fatty alcohols. Subsequent application of ANOVA-simultaneous component analysis and Principal Component Analysis revealed that all three BG diets increased bile acid faecal excretion compared to the control group. The bile acid excretion was found to be different in all three BG diets and the MBG group showed a significantly higher level of faecal secondary bile acids, including deoxycholic acid, hyodeoxycholic acid, and lithocholic acid. We hypothesise that the hydrophobic surface of the secondary bile acids, which are known to cause colon cancer, has high affinity to the hydrophobic surfaces of cellulosic blocks of the BG. This in vivo study demonstrates that the molecular weight and/or block structures of BG modulate the excretion of secondary bile acids. This finding suggests that developing diets with designed BGs with an optimal molecular structure to trap carcinogenic bile acids can have a significant impact on counteracting cancer and other lifestyle associated diseases.

Proliposomes for oral delivery of total biflavonoids extract from Selaginella doederleinii: formulation development, optimization, and in vitro-in vivo characterization.

PURPOSE: Amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone are five major active ingredients in the total biflavonoids extract from Selaginella doederleinii (TBESD) with favorable anticancer properties. However, the natural-derived potent antitumor agent of TBESD is undesirable due to its poor solubility. The present study was to develop and optimize a proliposomal formulation of TBESD (P-TBESD) to improve its solubility, oral bioavailability and efficacy. MATERIALS AND METHODS: P-TBESD containing a bile salt, a protective hydrophilic isomalto-oligosaccharides (IMOs) coating, were successfully prepared by thin film dispersion-sonication method. The physicochemical and pharmacokinetic properties of P-TBESD were characterized, and the antitumor effect was evaluated using the HT-29 xenograft-bearing mice models in rats. RESULTS: Compared with TBESD, the relative bioavailability of amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone from P-TBESD were 669%, 523%, 761%, 955% and 191%, respectively. The results of pharmacodynamics demonstrated that both TBESD and P-TBESD groups afforded antitumor effect without systemic toxicity, and the antitumor effect of P-TBESD was significantly superior to that of raw TBESD, based on the tumor growth inhibition and histopathological examination. CONCLUSION: Hence, IMOs-modified proliposomes have promising potential for TBESD solving the problem of its poor solubility and oral bioavailability, which can serve as a practical oral preparation for TBESD in the future cancer therapy.

MALDI-Mass Spectrometry Imaging to Investigate Lipid and Bile Acid Modifications Caused by Lentil Extract Used as a Potential Hypocholesterolemic Treatment.

This paper reports matrix-assisted laser desorption/ionization mass spectrometry imaging to investigate systematic effects of a lentil extract treatment to lower cholesterol levels. For this purpose, mass spectrometry imaging was used to spatially investigate modifications in the lipid composition and cholesterol levels in the brain, liver, and intestines as well as bile acids in the liver and intestine of rats treated with lentil extract. Neither the lipid composition nor cholesterol levels in the brain samples were found to be significantly different between the treated and not-treated animal groups. The hypercholesterolemic livers showed signs of steatosis (lipid marker PG 36:4), but no modifications in bile acid, cholesterol, and lipid composition. We found significant differences (AUC > 0.75) in the intestines regarding bile acid and lipid composition after treatment with the lentil extract. The treated rats showed a decreased reabsorption (increased excretion) of ursodeoxycholic acid, deoxycholic acid, and chenodeoxycholic acid and an increased deconjugation of taurine-conjugated bile acids (taurochenodeoxycholic acid, taurodeoxycholic acid, taurocholic acid, and 3-keto-taurocholic acid). This indicates that the lentil extract lowers the total cholesterol level in two synergic ways: (i) it increases the excretion of bile acids; hence, new bile acids are produced in the liver from serum cholesterol and (ii) the prebiotic effect leads to free taurine which upregulates the de novo synthesis of bile acid from cholesterol while activating LDL receptors. We demonstrate here that mass spectrometry imaging is a valuable tool for a better understanding of the effects of treatments such as for the synergistic cholesterol-lowering effect of the lentil extract.

Molecular Insights into the Mechanisms Underlying the Cholesterol- Lowering Effects of Phytosterols.

Dietary phytosterols, which comprise plant sterols and stanols, reduce plasma Low-Density Lipoprotein-Cholesterol (LDL-C) levels when given 2 g/day. Since this dose has not been reported to cause health-related side effects in long-term human studies, food products containing these plant compounds are used as potential therapeutic dietary options to reduce LDL-C and cardiovascular disease risk. Several mechanisms have been proposed to explain the cholesterol-lowering action of phytosterols. They may compete with dietary and biliary cholesterol for micellar solubilization in the intestinal lumen, impairing intestinal cholesterol absorption. Recent evidence indicates that phytosterols may also regulate other pathways. Impaired intestinal cholesterol absorption is usually associated with reduced cholesterol transport to the liver, which may reduce the incorporation of cholesterol into Very-Low- Density Lipoprotein (VLDL) particles, thereby lowering the rate of VLDL assembly and secretion. Impaired liver VLDL production may reduce the rate of LDL production. On the other hand, significant evidence supports a role for plant sterols in the Transintestinal Cholesterol Excretion (TICE) pathway, although the exact mechanisms by which they promote the flow of cholesterol from the blood to enterocytes and the intestinal lumen remains unknown. Dietary phytosterols may also alter the conversion of bile acids into secondary bile acids, and may lower the bile acid hydrophobic/hydrophilic ratio, thereby reducing intestinal cholesterol absorption. This article reviews the progress to date in research on the molecular mechanisms underlying the cholesterol-lowering effects of phytosterols.

[Chemical profiling for bile acid derivatives in yak bile].

Bile acids( BAs),the major constituents of bile,are also known to be potential biomarkers of various diseases,especially liver disease. The systematic analysis of BAs is believed to be of great importance towards the clarification of the effective material basis for bile-type medicines,and the diagnosis and therapy of related diseases as well. As a part of systematic study on bile-type medicine ongoing in our group,this study lays emphasis on the isomer discrimination,and the improvement of analytical method of BAs. Further,this method was subsequently applied to elucidate in depth the chemical profile of BAs in yak bile. Regarding isomer discrimination for BAs,we constructed relative response-collision energy curves( RRCECs) by high performance liquid chromatographyion trap-time of flight-mass spectrometry( HPLC-IT-TOF-MS) in combination with high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry( HPLC-Qtrap-MS). As a result,both the optimum collision energy( OCE) and CE_(50) exhibited great correlations with structural characteristics,thus enabling the isomer distinguishing,such as unconjugated BAs,glycine-conjugated BAs,and taurine-conjugated BAs. According to information provided by mass spectrometry,the comparison of OCE and CE_(50),retention time matching,combined with reference substances and database retrieval,a total of 30 bile acid derivatives were observed and identified in yak bile. The newly developed method could serve as a feasible tool for the in-depth characterization of BAs in bile and biological samples.

Formulation design, characterization, and in vitro and in vivo evaluation of nanostructured lipid carriers containing a bile salt for oral delivery of gypenosides.

BACKGROUND: Gypenosides (GPS) have been used as traditional medicine for centuries with various pharmacological effects. However, its therapeutic effects were restricted owing to the poor lipid and water solubility and low absorption. This study aimed to develop nanostructured lipid carriers (NLCs) containing a bile salt formulation (sodium glycocholate, SGC) for GPS, and to evaluate the potential of the GPS-SGC-NLCs as an oral delivery system. METHODS: The preparation of GPS-SGC-NLCs was investigated using a single-factor test and a central composite design of response surface methodology. In vitro release and pharmacokinetics studies were used to evaluate the dissolution and bioavailability of GPS. Furthermore, In vivo imaging and in situ intestinal perfusion studies were performed to investigate the absorption of the preparations in the gastrointestinal tract. RESULTS: The optimised formulation yielded nanoparticles with an approximate diameter of 146.7 nm, polydispersity of 0.137, zeta potential of -56.0 mV, entrapment efficiency of 74.22% and drug loading of 4.89%. An in vitro dissolution analysis revealed the sustained release of contents from GPS-SGC-NLCs over 48 h with 56.4% of the drug released. A pharmacokinetic analysis revealed an 8.5-fold increase of bioavailability of the GPS-SGC-NLCs compared with GPS powder. In vivo imaging and in situ intestinal perfusion studies showed that SGC-NLCs could significantly increase the absorption of GPS in intestinal tract. In vitro cytotoxicity evaluated using Caco-2 cells demonstrated that GPS-SGC-NLCs decrease the cytotoxicity of the drug. CONCLUSION: The SGC-NLC formulation can significantly improve the absorption of GPS, which provides an effective approach for enhancing the oral absorption of drugs.

Novel hypolipidemic conjugates of fatty acid and bile acid with lysine for linkage.

Novel fatty acid-bile acid conjugates (1a-1k) were designed and synthesized by coupling of the fatty acids to the 3-OH of bile acids using lysine for linkage. In the conjugates, the 24-COOH of the bile acids was kept intact to preserve liver-specific recognition. The ability of the newly synthesized conjugates (at 100 mg/kg dosage) to reduce total cholesterol (TC) and triglyceride (TG) levels in mice fed with high-fat diet (HFD) was evaluated. Conjugates of stearic acid with cholic acid and palmitic acid with ursodeoxycholic acid (at dosages of 50, 100, and 200 mg/kg) were further evaluated to determine their ability to reduce aspartate aminotransferase (AST), alanine aminotransferase (ALT), TC, and TG levels in mice fed with HFD. All conjugates showed potent hypolipidemic activity. Further investigation revealed that compounds 1c and 1 g not only dose-dependently reduced serum levels of TC and TG, but also inhibited the elevation of serum AST and ALT levels in mice fed with HFD. Thus, compounds 1c and 1 g are promising hypolipidemic agents with hepatocyte protective effects against HFD-induced liver damage.

Polysaccharides-protein interaction of psyllium and whey protein with their texture and bile acid binding activity.

Dietary fiber is a group of important food polysaccharides, which may improve gastrointestinal function and alter the bioavailability and nutritional value of other food components. The interaction mechanism of psyllium fiber (PSY) and whey protein (WP) and the influence on the characteristics of polysaccharides and protein were investigated. The results of circular dichroism spectra and differential scanning calorimetry analysis showed that PSY could protect WP by increasing its melting temperature. The textural profiles implied that WP could improve the edibility of the psyllium fiber. The IR spectrum and colorimetric assay indicated the product of Maillard reaction between psyllium and whey protein with the heating condition. The SEM showed that the structure of the mixture became stronger with higher temperature. Furthermore, the mixture with the ratio of WP/PSY as 1:2 had three times of the bile acid binding ability of PSY, which could be developed as a nutraceutical additive with prevention of hyperlipidemia.

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis.

To explain the cholesterol-reducing effects of dietary fibres, one of the major mechanisms proposed is the reduced reabsorption of bile acids in the ileum. The interaction of dietary fibres with bile acids is associated with their viscous or adsorptive effects. Since these fibre characteristics are difficult to investigate in vivo, suitable in vitro methodologies can contribute to understanding the mechanistic principles. We compared the commonly used centrifugal approach with a modified dialysis method using dietary fibre-rich materials from different sources (i.e., barley, citrus, lupin, and potato). Digestion was simulated in vitro with oral, gastric, and small intestinal digestion environments. The chyme was dialysed and released bile acids were analysed by high-performance liquid chromatography. The centrifugation method showed adsorptive effects only for cholestyramine (reference material) and a high-fibre barley product (1.4 µmol taurocholic acid/100 mg dry matter). Alternatively, the dialysis approach showed higher values of bile acid adsorption (2.3 µmol taurocholic acid/100 mg dry matter) for the high-fibre barley product. This indicated an underestimated adsorption when using the centrifugation method. The results also confirmed that the dialysis method can be used to understand the influence of viscosity on bile acid release. This may be due to entrapment of bile acids in the viscous chyme matrix. Further studies on fibre structure and mechanisms responsible for viscous effects are required to understand the formation of entangled networks responsible for the entrapment of the bile acids.

Incorporating physiologically relevant mobile phases in micellar liquid chromatography for the prediction of human intestinal absorption.

Micellar liquid chromatography is a popular method used in the determination of a compound's lipophilicity. This study describes the use of the obtained micelle-water partition coefficient (log Pmw ) by such a method in the prediction of human intestinal absorption (HIA). As a result of the close resemblance of the novel composition of the micellar mobile phase to that of physiological intestinal fluid, prediction was deemed to be highly successful. The unique micellar mobile phase consisted of a mixed micellar mixture of lecithin and six bile salts, i.e. a composition matching that found in the human intestinal environment, prepared in ratios resembling those in the intestine. This is considered to be the first method to use a physiological mixture of biosurfactants in the prediction of HIA. As a result, a mathematical model with high predictive ability (R2 PRED = 81%) was obtained using multiple linear regression. The micelle-water partition coefficient (log Pmw ) obtained from micellar liquid chromatography was found to be a successful tool for prediction where the final optimum model included log Pmw and polar surface area as key descriptors with high statistical significance for the prediction of HIA. This can be attributed to the nature of the mobile phase used in this study which contains the lecithin-bile salt complex, thus forming a bilayer system and therefore mimicking absorption across the intestinal membrane.

Novel Semisynthetic Derivatives of Bile Acids as Effective Tyrosyl-DNA Phosphodiesterase 1 Inhibitors.

An Important task in the treatment of oncological and neurodegenerative diseases is the search for new inhibitors of DNA repair system enzymes. Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is one of the DNA repair system enzymes involved in the removal of DNA damages caused by topoisomerase I inhibitors. Thus, reducing the activity of Tdp1 can increase the effectiveness of currently used anticancer drugs. We describe here a new class of semisynthetic small molecule Tdp1 inhibitors based on the bile acid scaffold that were originally identified by virtual screening. The influence of functional groups of bile acids (hydroxy and acetoxy groups in the steroid framework and amide fragment in the side chain) on inhibitory activity was investigated. In vitro studies demonstrate the ability of the semisynthetic derivatives to effectively inhibit Tdp1 with IC50 up to 0.29 µM. Furthermore, an excellent fit is realized for the ligands when docked into the active site of the Tdp1 enzyme.