Bile Acid-binding Ability Research Articles

In Vitro Antioxidant and Hypocholesterolemic Potency of Melon (Cucumis melo L.) Seed Protein Hydrolysate

Protein hydrolysates have been reported to possess numerous bioactivities. However, research on melon (Cucumis melo L.) seed protein (MSP) hydrolysate is limited. This study aimed to analyze the antioxidant and hypocholesterolemic properties of MSP hydrolysate. Protein from melon seed was obtained by conventional alkaline extraction-isoelectric precipitation method. Enzymatic hydrolysis of MSP was carried out using three different proteases: pepsin, thermolysin, and trypsin, with the enzyme-to-substrate (E/S) ratio of 1:50 (w/w). The results showed that all hydrolysates exhibited antioxidant and hypocholesterolemic activity. The thermolysin-digested hydrolysate had significantly greater (p < 0.05) radical scavenging properties, while trypsin produced the highest (p < 0.05) metal ion chelating activity. At 2 mg/mL, thermolysin-derived MSP hydrolysate showed no significant difference (p > 0.05) in HMGR inhibition activity compared to pravastatin. Additionally, the thermolysin hydrolysate had significantly higher (p < 0.05) bile acid binding ability than other hydrolysates. Overall, the MSP hydrolysate produced by thermolysin exhibited stronger antioxidant and hypocholesterolemic activities when compared to those produced by pepsin and trypsin, suggesting its potential effectiveness in nutraceutical applications.

Coffee pulp simulated digestion enhances its in vitro ability to decrease emulsification and digestion of fats, and attenuates lipid accumulation in HepG2 cell model

The coffee industry produces a considerable quantity of coffee pulp (CP), a by-product with high levels of caffeine, phenolic compounds, and dietary fiber, which are reportedly involved in the lipid homeostasis regulation required to maintain human health. This work's objective was to evaluate the hypolipidemic activity of coffee pulp flour (CPF) and aqueous extract (CPE) after static simulated digestion by the assessment of their in vitro capacity to decrease emulsification and digestion of fats, and lipid-lowering capacity in HepG2 cells after the induction of intracellular fat accumulation. The CPF and CPE digested fractions displayed in vitro hypolipidemic properties by preserving the reduction of micellar cholesterol solubility (27–34%) and the secondary bile acid-binding capacity (22–30%), increasing their primary bile acid-binding ability (2.7-fold and 2.4-fold, respectively), and inhibiting the lipase and the HMGCR (77–79% and 36–85%, respectively) activities. Moreover, the hypolipidemic properties of non-digested fractions enhanced the CPF potential to decrease lipid absorption. Both ingredients (CPF and CPE) demonstrated lipid-lowering effects since they effectively counteract the accumulation of intracellular triglycerides and cholesterol triggered by palmitic acid in hepatic cells after the simulated digestion. This study suggests that phenolic compounds, caffeine, and dietary fiber may be responsible for the lipid-lowering properties exhibited by the CP ingredients and their composition differences affect the above-mentioned properties exhibited in the simulated digestion. These results contribute to demonstrating that the CPF and the CPE may act as modulators of pathways involved in hepatic lipid accumulation and could be a key element in its prevention.

Pentapeptide IIAEK ameliorates cholesterol metabolism via the suppression of intestinal cholesterol absorption in mice.

Dietary protein-derived peptides are effective in improving dyslipidemia and hypercholesterolemia. We previously identified a novel cholesterol-lowering pentapeptide IIAEK from milk beta-lactoglobulin. However, it remains unclear whether IIAEK affects the micellar solubility of cholesterol and the bile acid-binding ability to lower cholesterol. Moreover, there is no direct evidence that IIAEK inhibits intestinal cholesterol absorption and affects hepatic cholesterol and fecal steroid excretion in vivo. Herein, we showed that IIAEK did not affect the micellar solubility of cholesterol and the bile acid-binding ability. However, we found that IIAEK decreased serum and liver cholesterol levels and increased fecal steroid excretion in mice. Interestingly, IIAEK markedly suppressed the intestinal absorption of [3H]-cholesterol in mice. In conclusion, we found that IIAEK ameliorated cholesterol metabolism by suppressing intestinal cholesterol absorption without affecting in vitro micellar solubility of cholesterol and the bile acid-binding ability in mice.

Effect of Oat β-Glucan on the Structure and Properties of Soybean Protein Isolate During Maillard Reaction.

Maillard reaction (MR) with oat β-glucan changed the structure of soybean protein isolate (SPI), further leading to the enhancement of its functional properties. SPI was unfolded by MR, and the SPI conjugates with high molecular weight were identified. The water solubility of SPI was improved by cross-linking with hydrophilic β-glucan, while the hydrophobicity also increased along with the unfolding of the SPI. Cross-linking with β-glucan elevated the viscosity of SPI, thus enhancing viscosity-related physiological activities, including bile acid binding ability, fat binding capacity, and hypoglycemic activity, and the functional properties increased as the βG content involved in MR increased.

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods: antioxidant and bile acid-binding capacity

In this study, the structural characters, antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides (HRPs) obtained by the commonly used hot water (HRP-W), pressurized hot water (HRP-H), ultrasonic (HRP-U), acid (HRP-C) and alkali (HRP-A) assisted extraction methods were investigated. The results demonstrated that extraction methods had significant effects on extraction yield, monosaccharide composition, molecular weight, particle size, triple-helical structure, and surface morphology of HRPs except for the major linkage bands. Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability. The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities. Moreover, the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network (HRP-C, HRP-W and HRP-U), which exhibited stronger bile acid binding capacity. The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Physicochemical and functional property of the Maillard reaction products of soy protein isolate with L-arabinose/D-galactose.

Soy protein isolate (SPI) is widely used in the food industry because of its nutritional and functional properties. During food processing and storage, the interaction with co-existing sugars can cause changes in the structural and functional properties of SPI. In this study, SPI-l-arabinose conjugate (SPI:Ara) and SPI-d-galactose conjugate (SPI:Gal) were prepared using Maillard reaction (MR), and the effects of five-carbon/six-carbon sugars on the structural information and function of SPI were compared. MR unfolded and stretched the SPI, changing its ordered conformation into disorder. Lysine and arginine of SPI were bonded with the carbonyl group of sugar. The MR between SPI and l-arabinose has a higher degree of glycosylation compared to d-galactose. MR of SPI enhanced its solubility, emulsifying property and foaming property. Compared with SPI:Ara, SPI:Gal exhibited better aforementioned properties. The functionalities of amphiphilic SPI were enhanced by MR, SPI:Gal possessed better hypoglycemic effect, fat binding capacity and bile acid binding ability than SPI:Ara. MR endowed SPI with enhanced biological activities, SPI:Ara showed higher antioxidant activities, and SPI:Gal exhibited stronger antibacterial activities. Our work revealed that l-arabinose/d-galactose exhibited different effects on the structural information of SPI, and further affected its physicochemical and functional property. © 2023 Society of Chemical Industry.

Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, there are relatively few studies on the production of exopolysaccharide (EPS) by yeasts. Therefore, exploring the properties of EPS produced by yeast can not only enrich the source of EPS, but also play an important role in its future application in the food field. The aim of this study was to explore the biological activities of EPS (named SPZ) from Sporidiobolus pararoseus PFY-Z1, as well as the dynamic changes in physical and chemical properties that occur during simulated gastrointestinal digestion, and the effects of SPZ on microbial metabolites during fecal fermentation in vitro. The results revealed that SPZ had good water solubility index, water-holding capacity, emulsifying ability, coagulated skim milk, antioxidant properties, hypoglycemic activities, and bile acid-binding abilities. Furthermore, the content of reducing sugars increased from 1.20 ± 0.03 to 3.34 ± 0.11 mg/mL after gastrointestinal digestion, and had little effect on antioxidant activities. Moreover, SPZ could promote the production of short-chain fatty acids during fermentation for 48 h, in particular, propionic acid and n-butyric acid increased to 1.89 ± 0.08 and 0.82 ± 0.04 mmol/L, respectively. Besides this, SPZ could inhibit LPS production. In general, this study can help us to better understand the potential bioactivities, and the changes in bio-activities of compounds after digestion of SPZ.

Preparation, characterization and bioactivities of selenized polysaccharides from Lonicera caerulea L. fruits

Native polysaccharide was obtained from Lonicera caerulea L. fruits (PLP). Two selenized polysaccharides (PSLP-1 and PSLP-2) were synthesized by the microwave-assisted HNO3-Na2SeO3 method, where the selenium (Se) contents were 228 ± 24 and 353 ± 36 μg/g, respectively. The molecular weights of PLP, PSLP-1, and PSLP-2 were 5.9 × 104, 5.6 × 104, and 5.1 × 104 kDa, respectively. PSLP-1 and PSLP-2 contained the same type of monosaccharides as PLP but with different molar ratios. The main chain structure of the native polysaccharide was not changed after selenization. PLP, PSLP-1, and PSLP-2 contained the same six types of glycosidic bonds. Bioactivity assays revealed that the two selenized polysaccharides possessed better antioxidant activities than PLP, but their bile acid-binding abilities and inhibitory activities on acetylcholinesterase (AChE) had weakened. In summary, PLP, PSLP-1, and PSLP-2 may be promising Se supplements in functional foods and inhibitors for the treatment of AChE.

Nutritional and Chemical Composition of Sargassum zhangii and the Physical and Chemical Characterization, Binding Bile Acid, and Cholesterol-Lowering Activity in HepG2 Cells of Its Fucoidans.

Fucoidan is a marine sulfated polysaccharide that is rich in Sargassum and has a wide range of biological activities. In this study, the chemical composition and bile acid binding ability of six crude fucoidans were compared, the nutrition and chemical composition of Sargassum zhangii were analyzed, and fucoidan from Sargassum zhangii was extracted and purified. The purified fractions (ZF1, ZF2, and ZF3) were analyzed by physicochemical characterization, and the ability of binding bile acid and cholesterol lowering in HepG2 cells were evaluated. The results showed that the contents of sulfate in crude fucoidan from Sargassum Zhangii (ZF) was as high as13.63%. Its ability of binding bile acid was better than other five crude fucoidans. Sargassum zhangii was a kind of brown seaweed with high carbohydrate, and low fat and rich in minerals. The sulfate content of ZF1, ZF2, and ZF3 was 3.29%, 19.39%, and 18.89% respectively, and the molecular weight (Mw) was 4.026 × 105, 2.893 × 105, and 3.368 × 105, respectively. Three fucoidans all contained the characteristic absorption bands of polysaccharides and sulfate groups and were rich in fucose. Three fucoidans can bind to bile acid, and ZF2 showed the best binding capability. In vitro experiments showed that ZF1, ZF2, and ZF3 could reduce intracellular total cholesterol (TC) content in HepG2 cells without affecting their viability. ZF2 showed the best ability to reduce TC.

Antioxidant and hypolipidemic activities of pectin isolated from citrus canning processing water

In order to make full use of the citrus resource, antioxidant and hypolipidemic activities of pectin isolated from citrus fruit canning processing water were investigated. The crude citrus pectin (CLCP) and its three separated fractions (LCP0, LCP1 and LCP3) possessed considerable DPPH, hydroxyl and ABTS radical scavenging ability. These were also found to effectively decrease ROS level and improve SOD activity in the H2O2-induced oxidative stress HepG2 cell model. In an in vitro simulated gastrointestinal environment, all the four pectins showed remarkable bile acid-binding ability. CLCP, LCP1 and LCP3 exhibited appreciable activity in reducing total cholesterol (TC) and triglyceride (TG) levels in an oleic acid-induced high-fat HepG2 cell model. RT-qPCR assays revealed that pectins effectively down-regulated the mRNA expression level of fatty acid synthetase (FAS) and sterol regulatory element-binding protein (SREBP)-1c. Thus, down-regulation of mRNA expression FAS and SREBP-1c could be important mechanism of the pectins to lower blood lipids. The citrus pectins investigated in this work have potential as ingredients of functional foods due to the antioxidant and hypolipidemic activities.

In vitro and in vivo evaluation of the bile acid-binding properties of dried persimmon and its non-extractable proanthocyanidin fraction

Dried persimmons contain abundant insoluble tannins comprised of non-extractable proanthocyanidins (NEPAs). To determine the beneficial function of NEPAs, we studied the bile acid-binding ability of NEPAs using in vitro and in vivo experiments. For the in vitro evaluation, 70% (v/v) acetone-insoluble solids (AIS) with different NEPA levels was prepared from persimmon fruits during drying. AIS with higher NEPA levels displayed stronger bile acid-binding activity, and the highest NEPA levels can be obtained from mostly-dried fruits. The in vivo bile acid-excreting effect of dried persimmon powder (DP) and AIS was verified by feeding experiments using C57BL/6J mice. The average bile acid-excretion was in order of low-fat group (1.07 µmol/day) < high-fat (HF) group (3.03 µmol/day) < HF + AIS group (4.44 µmol/day) < HF + DP group (6.74 µmol/day). These results suggest that the bile acid-excreting function of the fruit is related to the presence of NEPAs, which are constitutive ingredients of dried persimmon.

Anti-degranulation and bile acid-binding activity of extracts from fruits and agro-industrial by-products

To evaluate the utility of fruits and by-products/wastes as bioactive materials, we investigated the anti-allergic effects of hot-water and ethanol extracts from various fruit by-products and medicinal fruits using a β-hexosaminidase release assay. Bile acid-binding ability, which is related to the acceleration of bile acid excretion, was also determined for hot-water extracts. Among the extracts, the ethanol extract of grape bunch stem showed the highest (63.6%) inhibition of degranulation, as assessed by β-hexosaminidase release from rat basophilic leukemia cells (RBL-2H3) at a dose of 100 μg/mL. The hot-water extract from grape seed contained the highest total polyphenol content (353 mg gallic acid equivalent/g dry extract), but the total polyphenol content did not show a high correlation with the anti-degranulation effect. A positive relationship between the inhibitory effect of degranulation and proanthocyanidin content (0.1–0.3 in A550) was observed, but higher concentrations of proanthocyanidins in the system showed adverse effects. Proanthocyanidin content was also related to the bile acid-binding ability of the hot-water extracts with the highest value from Chinese quince hot-water extract (95%, 47.7 mg/g dry extract). These results suggest that proanthocyanidin-rich extracts from fruits and agro-industrial by-products have bioactive potential and can be exploited as anti-degranulation and bile acid-eliminating materials.

Ameliorative effects of functional crude-chalaza hydrolysates on the hepatosteatosis development induced by a high-fat diet

Approximately 400 metric tons of egg chalazae, a byproduct in the liquid-egg processing plant, are produced yearly but always regarded as a waste in Taiwan. Our team successfully developed a crude egg chalaza hydrolysate by protease-A digestion (CCH-A). Free branched-chain amino acids, 3-aminoisobutyric acid, and β-alanine, and anserine were assayed in the CCH-A used in this study. Besides, the in vitro bile-acid binding ability and inhibitory lipase activity of CCH-As were demonstrated. Then, high-fat diet feeding for 10 wk caused hyperlipidemia, insulin resistance, and hepatosteatosis in hamsters (P < 0.05). However, CCH-A co-treatment decreased serum/liver triglyceride levels and lipid accumulation in livers by increasing daily fecal lipid/bile-acid outputs, upregulating fatty-acid β oxidation, and downregulating fatty-acid biosynthesis in livers (P < 0.05). CCH-A co-treatment also amended insulin resistance, augmented hepatic antioxidant capacity, and decreased liver damages and inflammatory responses (P < 0.05). Taken together, our results do not only demonstrate the hepatoprotective effects of CCH-As against a chronic high-fat dietary habit, achieving effects similar to Simvastatin, but also decrease the environmental burden of handling chalazae in the liquid-egg industry.

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.

Digestive Property and Bioactivity of Blackberry Polysaccharides with Different Molecular Weights.

In the present study, the digestion and fermentation of blackberry polysaccharides (BBPs) with different molecular weights (Mw) were investigated. The results showed that the Mw decrease rates of BBP, BBP-8, BBP-16, and BBP-24 were 77.48, 69.61, 56.87, and 52.89%, respectively. The antioxidant and α-glucosidase inhibitory activities of BBPs were decreased under gastrointestinal condition, which might be due to the variation of Mw during digestion. The bile acid-binding ability of BBPs showed an Mw-dependent manner for higher Mw polysaccharides with higher viscosity. Through fermentation, the BBPs affected the ecosystem of the intestinal tract by promoting the production of short-chain fatty acids, lowering the pH of colon, and decreasing the ratio of Firmicutes to Bacteroidetes. All BBPs showed almost a similar modulation effect on the gut bacteria, but the lower Mw polysaccharide was more easily utilized by bacteria.

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.

Effects of chicken-liver hydrolysates on lipid metabolism in a high-fat diet

The contents of free hydrophobic amino acids, taurine and carnosine/anserine were elevated after hydrolyzing chicken livers by pepsin and compared to dried chicken livers. Chicken-liver-hydrolysates (CLHs) exhibited in vitro inhibitory lipase activity and bile-acid binding ability (p<0.05). Forty-eight male hamsters were assigned randomly to the following groups: (1) chow diet; (2) high-fat diet (HFD); (3) HFD and 100mgCLH/kgBW; (4) HFD and 200mgCLH/kgBW; (5) HFD and 400mgCLH/kgBW; (6) HFD and 200mgcarnosine/kgBW. CLHs alleviated (p<0.05) serum oxidative stress and improved (p<0.05) the serum lipid profile in the high-fat dietary groups; meanwhile, improved (p<0.05) antioxidant abilities and decreased (p<0.05) lipid accumulation, oxidative stress and TNF-α/IL-1β levels in the livers. These benefits might result from regulations of lipid homeostasis and increased faecal bile-acid outputs (p<0.05). Hence, lipid-homeostasis and antioxidant abilities of CLHs in the high-fat dietary habit were demonstrated and were similar to pure carnosine.

Comparison of the effects of three persimmon cultivars on lipid and glucose metabolism in high-fat diet-fed mice.

We compared the effects of three persimmon cultivars, one nonastringent-type fruit (Fuyu) and two astringent-type fruits (Hiratanenashi and Hachiya), on the lipid and glucose metabolism of high-fat diet-fed mice. Persimmon samples prepared from young fruits of the three cultivars contained around 80% dietary fiber and differed in their bile acid-binding abilities and tannin contents. C57BL/6J mice were fed a modified AIN76 high-fat diet supplemented with 2% of each persimmon sample instead of cellulose for 10 wk. All cultivars significantly accelerated fecal bile acid secretion, depending on the bile acid-binding ability of the cultivars. Hiratanenashi and Hachiya, the cultivars with a strong bile acid-binding ability, prevented any increase in fasting blood glucose and plasma nonesterified fatty acid levels. Hachiya, the cultivar with the highest tannin content, also tended to prevent an increase in plasma non-high-density lipoprotein cholesterol levels. However, Fuyu, the cultivar with the lowest bile acid-binding ability and tannin content, had no effect on lipid or glucose metabolism. These effects linked to expression of the genes related to lipid and energy metabolism, including the cytochrome P450 7A1 gene in the liver and the uncoupling protein 3 gene in the brown adipose tissue. These results indicate that the beneficial effects of these cultivars on lipid and glucose metabolism are closely related to their bile acid-binding ability and tannin content.

柿未成熟果実由来食物繊維の胆汁酸吸着能に対する加熱の影響とパン素材への応用

柿の未成熟果実から調製したタンニン含量の高い食物繊維（柿繊維）は胆汁酸吸着能を有する．この柿繊維がパンの素材として利用可能かを調べるために，柿繊維に対する熱処理の影響を検討した．また，柿繊維を添加したパンを焼成し，動物実験で胆汁酸排泄促進効果を検討した．180°Cで20分間処理すると，柿繊維の胆汁酸吸着能は20%低下した．しかし，10% (w/w）の柿繊維を添加したパンをマウスに摂取させると糞への胆汁酸排泄が2倍に増加した．これらの結果から柿繊維はパンに添加できる機能性食品素材であると考えられる．

In vitro antihyperlipidemic activity of triterpenes from stem Bark of Protorhus longifolia (Benrh) Engl.

Obesity is a common disorder of carbohydrate and fat metabolism. In an effort to discover new more effective drugs against obesity and its co-morbidities, we investigated the in vitro antihyperlipidemic activity of two triterpenes (3β-hydroxylanosta-9,24-dien-21-oic acid and methyl-3β-hydroxylanosta-9,24-dienoate isolated from stem bark of Protorhus longifolia and characterized through NMR, LC-MS, IR. The inhibitory activity of the triterpenes was evaluated on selected lipid (pancreatic lipase and cholesterol esterase) and carbohydrate (disaccharidases, α- glucosidase) digestive enzymes. The inhibitory activity of the compounds on hormone-sensitive lipase and the ability to bind bile acids were also evaluated. Furthermore, the effect of the compounds on cellular (muscle cells, C2C12 and fat cells, 3T3-L1) glucose uptake was investigated. The triterpenes effectively inhibited the activities of pancreatic lipase, cholesterol esterase, and hormone-sensitive lipase with IC50 values ranging from 26.6 to 430 µg/ml, and showed to varying degree inhibition of maltase and other disaccharidases. The compounds showed moderate bile acid binding ability and at 50 µg/ml, both compounds also mimicked insulin character by effectively stimulating glucose uptake in both the C2C12 and 3T3-L1 cells. It is apparent that the compounds possess hypolipidemic properties.