Cholesterol Precipitation Research Articles

Functional Disorders of the Biliary Tract and Cholelithiasis: Analysis of a Possible Relationship

Aim: Diagnostic criteria for functional disorders of the biliary tract are presented in the materials of the Rome IV consensus, as well as expert councils of Russian and foreign specialists. Episodes of functional biliary pain are caused by a violation of bile outflow through the cystic duct and sphincter of Oddi. It has been suggested that there is a “biliary continuum” in which in some patients’ biliary dysfunction is transformed into cholelithiasis. Key points. Lithogenic bile is considered as the pathophysiological basis for the development of biliary dyskinesia and cholelithiasis. Lithogenic bile provokes inflammation of low grades in the mucous membrane of the biliary tract, decreased contractility of the gallbladder and impaired relaxation of the biliary sphincters, impaired physiological response to cholecystokinin. Changes in motility of the biliary tract may be associated with the influence of hydrophobic bile salts and impaired eicosanoid metabolism. Hyperplasia of the epithelium and muscle layer, hypersecretion of mucin and cholesterol precipitation further impair the outflow of bile. Experimental data and some clinical observations indicate the possibility of transformation of biliary dysfunction into cholelithiasis. Dysfunction of the sphincter of Oddi is one of the possible consequences of cholecystectomy and, in fact, acts as a variant of postcholecystectomy syndrome. The basis for the treatment of biliary dysfunctions are antispasmodics of different classes, which can be combined with ursodeoxycholic acid. The biliary tract-selective antispasmodic hymecromone has shown high effectiveness in relieving biliary pain, which also has a moderate choleretic effect and the ability to prevent the crystallization of cholesterol in bile and can be used both for functional diseases and for cholelithiasis. The domestic drug hymecromone “Odecromone” entered the pharmaceutical market. Conclusion. There is no doubt that the relevance of further study of the patterns of development of biliary dysfunctions and GI is obvious. The study of this problem will contribute to the development of effective preventive approaches, including in the field of nutraceuticals.

Gallstones: The thing in itself.

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Process intensification of cooling crystallization of cholesterol from acetone solution using CO2 gas bubbles: Experiments and modeling

The present work investigates dependence of heterogeneous nucleation of solids on the gas bubble-solution interface in a process termed as "Precipitation by Gas-Bubbling" (PGB), through experiments and modeling. This process involves bubbling of CO2 gas at ambient condition through a solution of cholesterol in acetone, which is simultaneously cooled by an external coolant. The process parameters selected are coolant temperature, initial solution concentration, and CO2 flow rate. The flowing CO2 gas bubbles facilitate reduction in metastable zone width and induction time for cholesterol precipitation, rendering more efficient surface-mediated crystallization, thereby enabling process intensification of cooling crystallization. Faster precipitation of cholesterol at higher CO2 flow rate, i.e., higher CO2 bubble-solution interfacial area, demonstrates gas bubble-solution interface acting as a substrate for heterogeneous nucleation. Accordingly a mechanism for heterogeneous nucleation of cholesterol is proposed and validated by developing a model for prediction of final average particle size. The kinetic model parameters, namely, the pre-exponential factor as per the classical nucleation theory, and the crystal growth coefficient are regressed by comparing the predicted values of average particle size with the corresponding experimental data, and are found to be proportional to the surface area of gas bubbles and in turn on CO2 flow rate.

Study of association of H. pylori infection of the gall bladder and calculous cholecystitis

Background: Helicobacter pylori infection of the gallbladder has been shown to increase the precipitation of cholesterol to form stones. Also it has been shown that urease induced calcium precipitation by Helicobacter species may initiate gallstone formation. This has raised a question about the possible role of Helicobacter species in the aetiology of gallbladder diseases especially cholelithiasis. Owing to conflicting results on the topic in the studies presently available and more so, only a few studies being reported in Northern India regarding this aspect and additionally having discordant findings. Our study was conceptualized in the Southern India scenario. Methods: During 18 months study period those diagnosed with calculous cholecystitis with USG, patients underwent Laparoscopic Cholecystectomy, the gall bladder specimen sent for histopathological examination for the presence of H. pylori and the mucosal changes associated with infection of the gallbladder with Helicobacter pylori. Results: No statistical significance was seen between H. pylori and gender. Among those having H. pylori majority were females. (p=0.23). No statistical significance was seen between H. pylori and type of stone. Among those having H. pylori majority were pigmented type. (p=0.67) High statistical significance was seen between H. pylori and Inflammatory mononuclear infiltrate. P

Green tea catechin: does it lower blood cholesterol?

Tea is one of the most popular beverages in the world, especially in Asian societies. Green, oolong and black tea are three main types of tea products. Catechin is the principal polyphenol compound in all tea products including four major subgroup compounds, epigallocatechin gallate (EGCG), epicatehin (EC), epigallocatechin (EGC) and epicatechin gallate (ECG). Green tea contains highest amount of catechin compared to oolong and black tea since fermentation process can significantly reduce the amount of catechin in tea product, which polyphenol oxidase can convert catechins to theaflavins and thearubigins during fermentation process. Therefore, green tea catechin is becoming more and more attractive to nutritionists since it can provide several health benefits to human body. Cholesterol lowering effect is one of the health benefits been studied and proposed over decade. There are well documented evidences that suggested green tea catechin, in particular EGCG has the potential to lower blood cholesterol concentrations. Since the pool bioavailability and absorption ability of catechin, researchers believed that green tea catechin may significantly inhibit lipids absorption in intestine. Mechanisms are including inhibition of pancreatic lipase activity, lipids hydrolysis, and emulsification in intestine and precipitation of micellar cholesterol. In vitro studies, animal studies as well as most of human RCT, consistent results been observed that dietary intake of green tea beverages or extracts could significantly lower circulating cholesterol concentration, in particular lower LDL-C and total cholesterol level. However, in 2010, European Food Safety Authority (EFSA) denied the health claim of cholesterol lowering benefits of dietary intake of green tea or green tea catechins. In this presentation, current scientific evidences and EFSA judgment will be reviewed and discussed.

Clinical profile of patients with gallstone disease

The potential gallstone patient probably secretes a bile whose mean daily bile composition contains excessive cholesterol. The gallbladder bile from these patients thus becomes super saturated with cholesterol. If the level of supersaturation is very marked, precipitation of cholesterol may occur spontaneously. If only a moderate degree of supersaturation is present, nucleation may be necessary to initiate precipitation. After admission a detailed history was taken and clinical examination carried out. Various investigations were done to assess the patient. All 25 cases were subjected to laparotomy and all of them were evaluated before surgery with Ultrasonography. All patients had cholecystectomy as the main procedure. The decision regarding exploration of CBD was made on the basis of clinical, investigation and operative criteria. The commonest symptom in our series was pain abdomen (96%), followed by vomiting 32%, dyspespsia (24%), Jaundice (16%), fever (32%).

Gallstones—a force of NETure?

Immunology Gallstones are a painful and sometimes fatal condition that is one of the leading causes of hospitalization in the United States. They are thought to form when bile is concentrated and acidified in the gallbladder, leading to the supersaturation and subsequent precipitation of cholesterol and calcium salts. Munoz et al. report that neutrophils release neutrophil extracellular traps (NETs) after interacting with calcium or cholesterol crystals. These NETs contain extracellular DNA and elastase, which help fuel crystallization and gallstone assembly. Mice with defects in pathways required for NET formation were found to have gallstones of reduced size and number. One future therapeutic target for this condition may therefore lie in preventing neutrophils from casting their NETs. Immunity 51 , 443 (2019).

Bile salt deconjugation activity of Propionibacterium strains and their cholesterol co‐precipitation abilities

The present study investigated the deconjugation of bile salts and co‐precipitation of cholesterol with deconjugated bile salts by seven Propionibacterium spp. strains in vitro. Propionibacterium spp. could deconjugate sodium glycocholate (1.53–5.31 mM) and sodium taurocholate (0.08–0.25 mM) bile salts. The highest cholesterol precipitation (47.8 µg/mL) was determined with Propionibacterium freudenreichii subsp. freudenreichii SP3 strain in a 0.15% oxgall‐containing medium. Significant (P < 0.05) correlations were observed between cholesterol co‐precipitation and deconjugation of sodium glycocholate among the strains. In vitro bile salt deconjugation activity studies of P. freudenreichii subsp. freudenreichii SP3 strain revealed that this strain may have potential as a probiotic strain for deconjugation of bile salts in vivo studies.

In vitro assessment of hypocholesterolemic activity of Lactococcus lactis subsp. lactis

BackgroundCholesterol removal by isolated Lactococcus lactis subsp. lactis was investigated in vitro. The studied mechanisms were (1) assimilation of cholesterol by growing bacterial cells, (2) deconjugation of bile salts by bile salt hydrolase, (3) precipitation of cholesterol with deconjugated bile, (4) binding of cholesterol to the cell membrane, and (5) incorporation of cholesterol into the cell membrane.ResultLevels of cholesterol assimilated by growing cells (43.70%) were significantly higher than those assimilated by resting cells (12.93%) or counterpart dead cells (6.35%). Scanning electron micrographs indicated that cholesterol adsorbed to the bacterial cell wall. A comparison of IR spectra of Lactococcus lactis subsp. lactis grown with and without cholesterol using an FTIR spectroscopy database revealed intensity changes associated with sulfamide bonds, P–H stretching and the C≡C bonds. Precipitation of cholesterol upon deconjugation of glycocholate was higher (5.53 μg/ml) than that observed upon taurocholate (3.7 μg/ml).ConclusionsThe present study suggested the ability of probiotic Lactococcus lactis subsp. lactis to reduce its cholesterol level through several different mechanisms. Consequently, this probiotic bacterium showed an interested potential of application in cholesterol reduction to be a novel and save prospect in resolving hypocholesteremia and related diseases.

Activity Test of Suji Leaf Extract (Dracaena angustifolia Roxb.) on in vitro cholesterol lowering

Cholesterol is a natural substance with physical characteristic similar to fat but has a steroidal group. The body requires cholesterol in normal amount; however, it will harm the body in excess amount. High cholesterol levels in the blood are dangerous because of the precipitation of cholesterol and other fatty substances resulting in atherosclerosis. Suji leaf (Dracaena angustifolia Roxb.) used as a natural dye has a high flavonoid content that is inferred to have cholesterol-lowering activity. This study aims to test the in vitro activity of suji leaf (Dracaena angustifolia Roxb.) extract in decreasing cholesterol level with various concentrations and to find the effective concentration (EC50). The method of extraction used was remaceration method with 70% ethanol solvent. Analysis of cholesterol-lowering activity was done by Lieberman-Burchard method by making variation of ethanol extract 400 ppm, 500 ppm, 600 ppm, 700 ppm, and 800 ppm. The results showed the percentage of cholesterol-lowering activity by 33.62%, 36.15%, 46.61%, 56.39% and 64.05% respectively. Value of EC50 activity of suji leaf extract is 632.50 ppm.

Atherosclerosis Induced by a High-Cholesterol and High-Fat Diet in the Inbred Strain of the Wuzhishan Miniature Pig

ABSTRACTCoronary artery disease has a significant genetic predisposition, which mainly results from atherosclerosis. Miniature pig is an excellent model to investigate atherosclerosis. This study investigated whether the occurrence and development of atherosclerosis in the Wuzhishan miniature pigs (WZSPs) that were closely bred 12 generations had better consistency. The WZSPs (n = 9) were fed a high-cholesterol and high-fat diet (HCFD). After continuous feeding, 3 WZSPs each were sacrificed at 6, 8, and 12 months, respectively, and the general clinical manifestations and serological indexes were detected. The pathological changes of the major arteries and main organs were recorded. The results showed WZSPs were quite susceptible to the HCFD. At 6 months, plaque lesions appeared in the abdominal aorta and iliac artery, while at 8 months, they appeared in the coronary artery. At 12 months, atherosclerotic lesions could be found in all major arteries, while lipid core, cholesterol precipitation, and calcium deposition appeared in the most serious sites. The progression of arterial lesions and distribution of the lesions were highly consistent in the pigs. However, apparent variations in serum markers were observed. In conclusion, inbred WZSP is a good model to investigate atherosclerosis and has good predictability for the occurrence and development of the disease.

Osteopontin Deficiency Alters Biliary Homeostasis and Protects against Gallstone Formation.

The precipitation of excess biliary cholesterol as solid crystals is a prerequisite for cholesterol gallstone formation, which occurs due to disturbed biliary homeostasis. Biliary homeostasis is regulated by an elaborate network of genes in hepatocytes. If unmanaged, the cholesterol crystals will aggregate, fuse and form gallstones. We have previously observed that the levels of osteopontin (OPN) in bile and gallbladder were reduced in gallstone patients. However, the role and mechanism for hepatic OPN in cholesterol gallstone formation is undetermined. In this study, we found that the expression of hepatic OPN was increased in gallstone patients compared with gallstone-free counterparts. Then, we observed that OPN-deficient mice were less vulnerable to cholesterol gallstone formation than wild type mice. Further mechanistic studies revealed that this protective effect was associated with alterations of bile composition and was caused by the increased hepatic CYP7A1 expression and the reduced expression of hepatic SHP, ATP8B1, SR-B1 and SREBP-2. Finally, the correlations between the expression of hepatic OPN and the expression of these hepatic genes were validated in gallstone patients. Taken together, our findings reveal that hepatic OPN contributes to cholesterol gallstone formation by regulating biliary metabolism and might be developed as a therapeutic target for gallstone treatments.

A lipidomic analysis approach in patients undergoing lipoprotein apheresis

Lipoprotein apheresis such as heparin-induced extracorporal LowDensityLipoprotein (LDL) Cholesterol precipitation (HELP) reduces apolipoprotein B-containing lipoproteins, most importantly low-density-lipoprotein (LDL), and lipoprotein (a) [Lp(a)]. It is used in patients with atherosclerotic disease and therapy-refractory hypercholesterolemia or progressive atherosclerotic disease in patients with elevated Lp(a). While lipid-lowering effects of lipoprotein apheresis are well-established, there are only sparse data regarding the effect of apheresis on individual omega-6 and omega-3 polyunsaturated fatty acids (n-6 PUFA and n-3 PUFA), such as arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which could increase (AA) or decrease (EPA and DHA) cardiovascular risk.Here we analyzed different omega-6 and omega-3 fatty acids in the blood of patients undergoing a single HELP apheresis procedure using gas chromatography (GC). Furthermore, we assessed the effect of HELP treatment on formation of lipid metabolites and mediators arising from these polyunsaturated fatty acids in the plasma by LC/ESI-MS/MS. Lipoprotein apheresis reduced the concentrations of fatty acids analyzed in the plasma by 40–50%. This was similar for AA, EPA and DHA. The reduction in fatty acid plasma levels was similar to the reduction of total triglycerides. However there was a trend towards an increase of PUFA metabolites associated with platelet activation, such as 12-hydroxyeicosatetraenoic acid (12-HETE) and 14-hydroxydocosahexaenoic acid (14-HDHA).These data indicate that HELP apheresis could interfere with achieving higher levels of n-3 PUFA in the plasma. Lipid apheresis treatment might also increase the formation of potentially pro- as well as anti-inflammatory lipid mediators derived from AA or EPA and DHA.

Cardiac Tamponade: A Rare Presentation of Childhood Hypothyroidism.

Dear Editor, Myxedema heart disease is a well-known entity. Pericardial effusions have been reported in 50-73% of pediatric patients with hypothyroidism in various series (1, 2), but none of these describes the symptomatic pericardial effusions or cardiac tamponade. A 5- year-old female child presented with complaints of periorbital puffiness and mild abdominal distension intermittently for last 6 months. She was symptomatically treated with diuretics off and on without much benefit. This time she reported to pediatric emergency with progressively increasing respiratory distress for last 5 days. There was no history of any fever, decreased urine output, orthopnea, or Koch’s contact. She was third live issue of non-consanguineous marriage born by normal vaginal delivery following uncomplicated pregnancy. She was immunized for age with no significant family history. She had history of global development delay; development age corresponded to 3 years. On examination she was afebrile with HR of 70/min, RR of 44/min and BP of 80/60 mmHg with pulsus paradoxus. She had coarse facies with dilated neck veins. Her skin was dry and coarse. She had short stature with height less than 3rd centile and normal weight. Her cardiovascular examination revealed silent precordium. Her cardiac border was extending 1.5 cm beyond right sternal margin and 2 cm beyond apex beat on left side on percussion. Her heart sounds were muffled with no murmur. Her abdominal examination revealed free fluid in abdomen. Rest of systemic examination was normal. Chest X ray revealed massive cardiomegaly with CT ratio of 678%. Immediate ECHO done on urgent basis, revealed large pericardial effusion with collapse of right atrium during diastole with ejection fraction of 65% and intrinsically normal heart. ECHO guided pericardiocentesis drained 150 ml of fluid. The fluid was clear with 3.3 mg/dl of proteins, 110 mg/dl cholesterol, 20 RBC/µL, 14 lymphocytes/µL, 7 neutrophils/µL and rest of pericardial examination were normal. Rest of hematological and urinary examination was normal. Searching for tuberculosis was also negative. In view of features suggested of hypothyroidism on clinical examination and non infectious nature of pericardial fluid, her thyroid profile was done which was suggested of hypothyroidism with T3 = 0.92 nmol/L (1.39-3.7nmol/L), T4 = 3.2 µg/dl (5.5-12.8µg/dl), TSH= 40 mIU/L(0.7-6.4 mIU/L). Her anti TPO antibodies were negative and USG neck revealed mild enlargement of thyroid gland. She was started on L-thyroxine with dosage of 4 µg/kg/d. She responded to treatment with thyroid replacement and her pericardial effusion disappeared after 2 months on repeat ECHO. She is on regular follow up and showing improvement in each regards. Although mild to moderate pericardial effusions of no clinical significance are frequently reported in pediatric myxedema heart disease, but cardiac tamponade is rare. Literature reports only 2 adolescent girls with cardiac tamponade in association with hypothyroidism, but none has been reported in young children. Author reports a rare case of cardiac tamponade in a young child with previously unrecognized hypothyroidism. Besides bradycardia, minimal pericardial effusions are most common cardiac manifestations of clinical hypothyroidism in adults. Most of pediatric age group patients presenting with this belonged to neonatal period or to Down’s syndrome (1, 2). Myxedema heart disease was first described by Zondek in 1918 and was completely defined by Fahr in 1925 (3). The pathophysiological derangements responsible for pericardial effusions are increased egress of proteins from blood, decreased lymphatic clearance of proteins and abnormal electrolyte metabolism (4). At molecular level, commonly observed signs or symptoms in hypothyroidism are attributed to changes in expression of various gene products, which includes alpha myosin heavy chain, beta-1 adrenergic receptors, voltage gated potassium channels and sarcoplasmic reticulum calcium ATPase (5). The rarity of cardiac tamponade in hypothyroidism is attributed to slow accumulation of fluid and marked distensibility of pericardium (6). Alexander first described ‘Gold paint effusion’ to describe the golden brown appearance of pericardial fluid due shimmering satin cholesterol crystals (7). High cholesterol content of pericardial fluid have been attributed to disturbance of lipid metabolism; probably churning action of heart causing precipitation of cholesterol from pericardial fluid. Treatment of cardiac tamponade due to hypothyroidism involves urgent pericardiocentesis followed by thyroxine replacement. Treatment of pericardial effusion with thyroxine replacement leads to resolution of effusion in 2-12 months (5). In conclusion myxedema heart disease should be suspected in any child with symptoms suggestive of hypothyroidism, presenting with even hemodynamic-ally significant pericardial effusion or cardiac tamponade. Patients with hypothyroidism-associated pericardial effusion should be monitored for development of cardiac tamponade.

Mechanisms of cholesterol and saturated fatty acid lowering by Quillaja saponaria extract, studied by in vitro digestion model.

Quillaja saponin extracts are known to reduce plasma cholesterol levels in humans. Here we study the mechanism of this effect with Quillaja Dry saponin extract (QD). In vitro model of triglyceride lipolysis is used to quantify the effect of QD on the solubilization of cholesterol and of the lipolysis products (fatty acids and monoglycerides) in the dietary mixed micelles (DMM). We found that QD extract decreases significantly both the cholesterol (from 80% to 20%) and saturated fatty acids (SFA, from 70% to 10%) solubilised in DMM. Series of dedicated experiments prove that QD may act by two mechanisms: (1) direct precipitation of cholesterol and (2) displacement of cholesterol from the DMM. Both mechanisms lead to increased cholesterol precipitation and, thus, render cholesterol bio-inaccessible. We prove also that the saponin molecules are not the active component of QD, because highly purified Quillaja extract with very similar saponin composition does not exhibit cholesterol-lowering or SFA-lowering effect. The effect of QD extract on cholesterol solubilisation is most probably caused by the high-molecular weight polyphenol molecules, present in this extract. The reduced SFA solubilisation is caused by Ca(2+) ions of relatively high concentration (1.25 wt%), also present in QD extract, which precipitate the fatty acids into calcium soaps.

An integrated analysis of differential miRNA and mRNA expressions in human gallstones.

Gallstone disease, including cholesterol precipitation in bile, increased bile salt hydrophobicity and gallbladder inflammation. Here, we investigated miRNA and mRNA involved in the formation of gallstones, and explored the molecular mechanisms in the development of gallstones. Differentially expressed 17 miRNAs and 525 mRNA were identified based on Illumina sequencing from gallbladder mucosa of patients with or without gallstones, and were validated by randomly selected 6 miRNAs and 8 genes using quantitative RT-PCR. 114 miRNA target genes were identified, whose functions and regulating pathways were related to gallstones. The differentially expressed genes were enriched upon lipoprotein binding and some metabolic pathways, and differentially expressed miRNAs enriched upon ABC transportation and cancer related pathways. A molecular regulatory network consisting of 17 differentially expressed miRNAs, inclusive of their target genes, was constructed. miR-210 and its potential target gene ATP11A were found to be differentially expressed in both miRNA and mRNA profiles. ATP11A was a direct target of miR-210, which was predicted to regulate the ABC-transporters pathway. The expression levels of ATP11A in the gallstone showed inverse correlation with miR-210 expression, and up-regulation of miR-210 could reduce ATP11A expression in HGBEC. This is the first report that indicates the existence of differences in miRNA and mRNA expression in patients with or without gallstones. Our data shed light on further investigating the mechanisms of gallstone formation.

Contact angle hysteresis and phase separation in dry phospholipid films with cholesterol deposited on mica surface

A series of apparent advancing and receding contact angles of water and diiodomethane was measured on the phospholipid/cholesterol monolayers physisorbed on the mica surfaces. It was found that the contact angles and their hystereses vary significantly depending on the lipid film composition and mutual miscibility of both components. These changes were much greater for water than diiodomethane. When the phase separation occurred, the hysteresis of water contact angle significantly decreased whereas the diiodomethane contact angle hysteresis increased considerably. Different behavior of both liquids may result from different mechanisms of the liquid droplets penetration/retention and points to structural changes that occur within the monolayers, including molecules rearrangement when exposed to water. The structure of the studied monolayer surfaces was confirmed by means of the microscopic techniques. The images are a visual evidence of cholesterol precipitation out the binary films at their specific stoichiometry. The results provide a new insight into the advancing/receding contact angles origin (and contact angle hysteresis) of polar and apolar liquids depending on the phospholipid/cholesterol monolayer composition, as well explanation of the origin of the contact angle hysteresis on the model biological surfaces, which are molecularly smooth.

Studies on Medicago lupulina saponins. 5. Isolation and chemical characterization of blossom saponins

The separation of saponins derived from <em>Medicago lupulina</em> L. flowers yielded two saponin fractions. The first one, made up of crystalline saponins, readily precipitable from water solution, was a mixture of three glycosides of soyasapogenol B. Acid hydrolysis of these saponins yielded soyasapogenol B and its three artifacts: soyasapogenols C. D and F. Xylose, rhamnose, galactose, glucose and glucuronic acid were found as sugar constituents. The second fraction obtained by cholesterol precipitation consisted of seven haemolytically active medicagenic acid glycosides. Their hydrolysis furnished medicagenic acid and glucose, xylose, rhamnose and traces of glucuronic acid.

Mechanisms of Cholesterol-Lowering Effects of Lactobacilli and Bifidobacteria Strains as Potential Probiotics with Their bsh Gene Analysis

The bile salt hydrolase (BSH) enzyme activities of human-derived lactic acid bacteria and bifidobacteria were evaluated. The highest enzyme activity was identified as 1.76 ± 0.23 U/mg protein for Bifidobacterium breve A26 and 1.42 ± 0.11 U/mg protein for Lactobacillus plantarum LA3. The bile salt deconjugation ability of the 6 isolates representing the highest BSH enzyme activity was calculated as the release of cholic acid and was between the range of 2.03 ± 0.22 and 1.05 ± 0.25 m<smlcap>M</smlcap>. The strains with high BSH enzyme activity also showed high deconjugation ability (p < 0.01). The effect of increasing bile concentrations on the growth of bacteria and their cholesterol removal abilities based on cholesterol precipitation were determined. Cholesterol removal in control medium was between 22.6 ± 0.4 and 26.5 ± 0.4%. The highest value was recorded at a 0.2% bile concentration. As the biliary concentration increased, a decrease in cholesterol removal and viability of the bacteria was noted in all strains. The percent of similarity of the bsh gene region between different genes was specified. The results may throw some light on proving the ability of these probiotics either as a novel alternative or as adjuvants to chemical drugs in treating hypercholesterolemia.

Black rice and anthocyanins induce inhibition of cholesterol absorption in vitro

Black rice (Oryza sativa L.) is often associated with blood lipid control. This study systematically assessed the inhibition of cholesterol absorption in vitro by black rice and explored cholesterol-lowering compounds present in this rice. Our results indicated that black rice extracts (BRE), which were aqueous, ethanol extracts and a fraction of macroporous resin caused the reduction of cholesterol absorption by inhibiting pancreatic lipase, decreasing the micellar cholesterol solubility and suppressing cholesterol uptake in Caco-2 cells. The inhibitory activity was positively associated with anthocyanin (cyanidin-3-glucoside (Cy-3-G) and peonidin-3-glucoside (Pn-3-G)) contents of the extracts. Therefore, the cholesterol absorption inhibiting properties of anthocyanins were further explored. The IC50 values of Cy-3-G and Pn-3-G against pancreatic lipase were 42.53 ± 4.45 and 18.13 ± 4.22 μg mL(-1), respectively. Kinetic analysis suggested that the enzymatic inhibitory mode of Cy-3-G and Pn-3-G belonged to the competitive type. In mixed micelles, Cy-3-G and Pn-3-G dose dependently reduced the solubility of cholesterol. Meanwhile, a potential mechanism of cholesterol reduction by anthocyanins was investigated. Results showed that anthocyanins led to precipitation of cholesterol from micellar solution, which may induce the reduction of cholesterol. In Caco-2 cells, Cy-3-G and Pn-3-G (40 μg mL(-1)) exhibited a significant reduction in cholesterol uptake, and the degree of this reduction was almost the same as that observed in the group treated with Ezetimibe at the same concentration. These findings provide important evidence that anthocyanins may partly contribute to the inhibitory effects of black rice on cholesterol absorption, and thus may be applied for the prevention and treatment of hypercholesterolaemia.