Inhibitors Of Cholesterol Esterase Research Articles

Identification and molecular binding mechanism of novel pancreatic lipase and cholesterol esterase inhibitory peptides from heat-treated adzuki bean protein hydrolysates

Heat-treated adzuki bean protein hydrolysates exhibit lipid-reducing properties; however, few studies have reported pancreatic lipase (PL) and cholesterol esterase (CE) inhibitory effects and elucidated the underlying mechanisms. In this study, we accomplished the identification of antiobesity peptides through peptide sequencing, virtual screening, and in vitro experiments. Furthermore, the mechanisms were investigated via molecular docking. The findings reveal that the action of pepsin and pancreatin resulted in the transformation of intact adzuki bean protein into smaller peptide fragments. The < 3 kDa fraction exhibited a high proportion of hydrophobic amino acids and displayed superior inhibitory properties for both PL and CE. Five novel antiobesity peptides (LLGGLDSSLLPH, FDTGSSFYNKPAG, IWVGGSGMDM, YLQGFGKNIL, and IFNNDPNNHP) were identified as PL and CE inhibitors. Particularly, IFNNDPNNHP exhibited the most robust biological activity. These peptides exerted their inhibitory action on PL and CE by occupying catalytic or substrate-binding sites through hydrogen bonds, hydrophobic interactions, salt bridges, and π-π stacking.

Triterpenoids from Protorhus longifolia Exhibit Hypocholesterolemic Potential via Regulation of Cholesterol Biosynthesis and Stimulation of Low-Density Lipoprotein Uptake in HepG2 Cells.

The increasing incidence of hypercholesterolemia-related diseases even in the presence of the currently available cholesterol-lowering drugs indicates a need to discover new therapeutic drugs. This study aimed to investigate the hypocholesterolemic potential of two triterpenoids isolated from Protorhus longifolia stem bark. In silico techniques and in vitro enzyme assays were used to evaluate the potential inhibition of cholesterol esterase and HMG-CoA reductase by the triterpenoids (ARM-2 and RA-5). The toxicity, modulation of low-density lipoprotein (LDL) uptake, and associated gene expression were determined in HepG2 hepatocytes. In silico molecular docking revealed that ARM-2 compared with RA-5 has a relatively stronger binding affinity for both enzymes. Both triterpenoids further demonstrated promising in silico drug-likeness properties and favorable ADMET profiles characterized by high intestinal absorption and lack of CYP450 enzyme inhibition. The compounds further showed, to varying degrees of efficacy, inhibition of cholesterol micellization as well as both cholesterol esterase and HMG-CoA reductase activities with IC50 values ranging from 16.4 to 41.1 μM. Moreover, enhanced hepatic cellular LDL uptake and the associated upregulation of the LDL-R and SREBP-2 gene expression were observed in the triterpenoid-treated HepG2 cells. It is evident that the triterpenoids, especially ARM-2, possess hypocholesterolemic properties, and these molecules can serve as leads or structural templates for the development of new hypocholesterolemic drugs.

Chemical composition and anti-cholesterol activity of tea (Camellia sinensis) flowers from albino cultivars.

Albino tea cultivars are mutant tea plants with altered metabolisms. Current studies focus on the leaves while little is known about the flowers. To evaluate tea flowers from different albino cultivars, the chemical composition and anti-cholesterol activity of tea flowers from three albino cultivars (i.e., Baiye No.1, Huangjinya, and Yujinxiang) were compared. According to the results, tea flowers from Yujinxiang had more amino acids but less polyphenols than tea flowers from the other two albino cultivars. A reduced content of procyanidins and a high chakasaponins/floratheasaponins ratio were characteristics of tea flowers from Yujinxiang. In vitro anti-cholesterol activity assays revealed that tea flowers from Yujinxiang exhibited stronger activity in decreasing the micellar cholesterol solubility, but not in cholesterol esterase inhibition and bile salt binding. It was noteworthy that there were no specific differences on the chemical composition and anti-cholesterol activity between tea flowers from albino cultivars and from Jiukeng (a non-albino cultivar). These results increase our knowledges on tea flowers from different albino cultivars and help food manufacturers in the cultivar selection of tea flowers for use.

Multiple Bioactivities of Peptides from Hydrolyzed Misgurnus anguillicaudatus

Misgurnus anguillicaudatus (loach) is a widely distributed benthic fish in Asia. In this study, the alkaline protease was used to hydrolyze loach, and the hydrolysate products of different molecular weights were obtained by membrane separation. In vitro antioxidant assays showed that the <3 kDa fraction (SLH-1) exhibited the strongest antioxidant activity (DPPH, hydroxyl radical and superoxide radical scavenging ability, and reducing power), while SLH-1 was purified by gel filtration chromatography, and peptide sequences were identified by LC-MS/MS. A total of six peptides with antioxidant activity were identified, namely SERDPSNIKWGDAGAQ (D-1), TVDGPSGKLWR (D-2), NDHFVKL (D-3), AFRVPTP (D-4), DAGAGIAL (D-5), and VSVVDLTVR (D-6). In vitro angiotensin-converting enzyme (ACE) inhibition assay and pancreatic cholesterol esterase (CE) inhibition assay, peptide D-4 (IC50 95.07 μg/mL, 0.12 mM) and D-2 inhibited ACE, and peptide D-2 (IC50 3.19 mg/mL, 2.62 mM), D-3, and D-6 acted as pancreatic CE inhibitors. The inhibitory mechanisms of these peptides were investigated by molecular docking. The results showed that the peptides acted by binding to the key amino acids of the catalytic domain of enzymes. These results could provide the basis for the nutritional value and promote the type of healthy products from hydrolyzed loach.

Co-extraction of soy protein and polysaccharide with lipid-lowering activity: Characterization of functional property, nutritional property and colonic fermentation property through a metabolomics approach

Defatted soy meal is a candidate for preparing lipid-lowering active ingredient. The study aimed to optimally co-extract soy protein and polysaccharide with lipid-lowering activity and improved functional and nutritional properties using non-conventional extraction techniques, i.e. thermal-, high pressure homogenization- and enzyme-assisted extraction. Non-conventional extraction enhanced the yields of soy protein and soluble saccharides and inactivated anti-nutrients. Soy extract (SE) prepared by pectinase-assisted extraction possessed not only strong in vitro lipid-lowering activity (i.e. cholesterol micellar inhibition activity, bile salts binding capacity, pancreatic lipase inhibition activity and cholesterol esterase inhibition activity), but also excellent functional (i.e. instant solubility of protein, low turbidity and acceptable color) and nutritional properties (i.e. none agglutinin activity). Resistant-digested fragment of 7S/11S played key role in lipid-lowering activity of SE. Moreover, SE beneficially altered colonic fermentation property of soy protein through promoting the release of bioactive peptides and organic acids, accelerating tryptophan and linoleic acid metabolism to produce indole acrylic acid, indole lactic acid and linoleic acid, and inhibiting putrefactive compounds (i.e. piperidine and tyramine). Oligosaccharide and polysaccharide in SE improved functional and nutritional properties of soy protein without compromising its lipid-lowering activity.

Nutraceutical and bioactive potential of high-quality date fruit varieties (Phoenix dactylifera L.) as a function of in-vitro simulated gastrointestinal digestion

The present study aims to investigate the digestive process (gastric and intestinal phases) effects on the survivability of total and individual phenolic compounds, and the in vitro health-related bioactive properties of four high-quality and commonly consumed dates (Phoenix dactylifera) varieties (Safawi, Khalas, Khudri, and Booman). Phenolic compounds were analyzed by HPLC-UV (at 275 nm) and a higher amount of phenolics were identified in Khalas and Booman intestinal digested extracts, compared to the other date varieties-based extracts, which corroborates with the total phenolic contents in those samples, with respective values of 186.5 and 358.14 mg GAE/100 g. Considering their bioactive potentialities, the highest DPPH radical scavenging activities, of around 320 TEAC µg/mL, were observed with Khalas and Khudri gastric extracts. In contrast, Khalas intestinal extract displayed the highest ABTS radical scavenging potential of 969 TEAC µg/mL. Moreover, the Safawi intestinal extract, along with Khalas and Booman gastric extracts, showed the highest increase in the α-glucosidase inhibition activity, compared to the other date varieties-based extracts. Safawi and Khalas intestinal extracts displayed the highest DPP-IV inhibition activities (IC50 of 2.85 µg/mL). Additionally, regarding the pancreatic lipase and cholesterol esterase inhibition, Khudri and Khalas varieties after intestinal digestion demonstrated the highest activities. These results suggested that the Khalas variety showed more potent bioactive properties than other date varieties, mainly related to the variations in the phenolic content between date varieties. Overall, this study provides additional insight into investigating these dates varieties upon their simulated gastro-intestinal digestion and exhibition of multifunctional bioactive properties.

Anti-inflammatory, cytotoxicity and antilipidemic properties: novel bioactivities of true cinnamon (Cinnamomum zeylanicum Blume) leaf

BackgroundThe leaf of Ceylon cinnamon (true cinnamon) is traditionally claimed for a variety of health benefits. However, reported scientific information is scanty and needs urgent attention for value addition.MethodsEthanolic (95%) and Dichloromethane:Methanol (DM, 1:1 v/v) leaf extracts of Ceylon cinnamon were evaluated for a range of medically important bioactivities namely anti-inflammatory [nitric oxide scavenging activity (NOSA), superoxide scavenging activity (SCA), COX1 and COX2 inhibition], growth inhibition & cytotoxicity against MCF7, HePG2 and AN3CA carcinoma cell lines, glutathionase-S-transferase (GST) inhibition and antilipidemic (anti-HMG-CoA reductase, anti-lipase, anti-cholesterol esterase, and cholesterol micellization inhibition) properties in vitro (n = 3). Further, a range of bioactive compounds in both leaf extracts was also quantified (n = 3).ResultsBoth leaf extracts had all the investigated bioactive compounds and possessed moderately potent bioactivities compared to the reference drugs used in the study. Ethanolic leaf extract (ELE) exhibited the highest activities (IC50: μg/mL) for NOSA (40.26 ± 0.52), SCA (696.24 ± 40.02), cholesterol esterase inhibition (110.19 ± 1.55), cholesterol micellization inhibition (616.69 ± 7.09), GST inhibition (403.78 ± 2.70) and growth inhibition (GI50: 144.84 ± 1.59-269.00 ± 0.51) & cytotoxicity (LC50: 355.44 ± 9.38-717.71 ± 23.69) against studied cancer cell lines. In contrast, COX1 & COX2 (IC50: 6.62 ± 0.85 and 44.91 ± 3.06 μg/mL) and HMG-CoA reductase & lipase inhibitory activities (36.72 ± 4.74 and 19.71 ± 0.97% inhibition at 200 and 600 μg/mL) were highest in DM extract. ELE also showed the highest quantities (0.81 ± 0.06-104.38 ± 1.79) of tested compounds (mg/g extract) where eugenol was the highest and gallic acid was the lowest among quantified.ConclusionBoth leaf extracts of Ceylon cinnamon had all the tested bioactive compounds and possess all the investigated bioactivities. This is the 1st study to report all the investigated bioactivities of the leaf of Ceylon Cinnamon.

Terminal Phenoxy Group as a Privileged Moiety of the Drug Scaffold-A Short Review of Most Recent Studies 2013-2022.

The terminal phenoxy group is a moiety of many drugs in use today. Numerous literature reports indicated its crucial importance for biological activity; thus, it is a privileged scaffold in medicinal chemistry. This review focuses on the latest achievements in the field of novel potential agents bearing a terminal phenoxy group in 2013–2022. The article provided information on neurological, anticancer, potential lymphoma agent, anti-HIV, antimicrobial, antiparasitic, analgesic, anti-diabetic as well as larvicidal, cholesterol esterase inhibitors, and antithrombotic or agonistic activities towards the adrenergic receptor. Additionally, for selected agents, the Structure–Activity–Relationship (SAR) is also discussed. Thus, this study may help the readers to better understand the nature of the phenoxy group, which will translate into rational drug design and the development of a more efficient drug. To the best of our knowledge, this is the first review devoted to an in-depth analysis of the various activities of compounds bearing terminal phenoxy moiety.

Phoenix dactylifera L. seed protein hydrolysates as a potential source of peptides with antidiabetic and anti-hypercholesterolemic properties: An in vitro study

This study aimed to explore the effect of enzymatic hydrolysis conditions (enzyme types and hydrolysis time) of date seed protein hydrolysates (DSPH) on in-vitro inhibition of molecular markers related with diabetic and hypercholesteremia. The DSPH was prepared using alcalase, bromelain, papain, and protease at different hydrolysis time (HT) (2, 4 and 6 h). Higher degree of hydrolysis was observed for papain at 6 h HT. The results showed that alcalase and bromelain generated DSPHs at 6 h HT greatly improved the pancreatic lipase inhibition activity while the cholesterol esterase inhibition activity was greatly enhanced with alcalase and protease at 6 h HT and papain generated DSPHs at 4 h HT. Bromelain generated DSPH displayed the highest inhibition of dipeptidyl peptidase-IV (DPP-IV) and amylase at 6 and 2 h hydrolysis time, respectively. All the enzymes at 2 h HT except that of papain showed the highest α-glucosidase inhibitory activities. These results revealed that the DSPH displayed enhanced inhibitory activities towards molecular markers related with diabetes and obesity and thus have promising potential to be used as health-promoting ingredients in the fabrication of functional foods.

Identification and synthesis of selective cholesterol esterase inhibitor using dynamic combinatorial chemistry

In this study, the concept of dynamic combinatorial chemistry (DCC) was applied to explore novel cholesterol esterase (CEase) inhibitors. In the presence of enzyme, two substrates (A1H3 and A2H3) were amplified from the dynamic combinatorial library (DCL), which was generated through reversible acylhydrazone formation reaction. In the in vitro biological evaluation, compound A1H3 exhibited not only potent (IC50 in nanomolar range) but also selective inhibition (>120 folds of selectivity for CEase over AChE). Furthermore, the binding pattern and possible binding mechanism were investigated in the kinetic experiment and molecular docking study, respectively.

Arylacetamide deacetylase as a determinant of the hydrolysis and activation of abiraterone acetate in mice and humans

AimAbiraterone acetate for metastatic castration-resistant prostate cancer is an acetylated prodrug to be hydrolyzed to abiraterone. Abiraterone acetate is known to be hydrolyzed by pancreatic cholesterol esterase secreted into the intestinal lumen. This study aimed to investigate the possibility that arylacetamide deacetylase (AADAC) expressed in enterocytes contributes to the hydrolysis of abiraterone acetate based on its substrate preference. Materials and methodsAbiraterone acetate hydrolase activity was measured using human intestinal (HIM) and liver microsomes (HLM) as well as recombinant AADAC. Correlation analysis between activity and AADAC expression was performed in 14 individual HIMs. The in vivo pharmacokinetics of abiraterone acetate was examined using wild-type and Aadac knockout mice administered abiraterone acetate with or without orlistat, a pancreatic cholesterol esterase inhibitor. Key findingsRecombinant AADAC showed abiraterone acetate hydrolase activity with similar Km value to HIM and HLM. The positive correlation between activity and AADAC levels in individual HIMs supported the responsibility of AADAC for abiraterone acetate hydrolysis. The area under the plasma concentration-time curve (AUC) of abiraterone after oral administration of abiraterone acetate in Aadac knockout mice was 38% lower than that in wild-type mice. The involvement of pancreatic cholesterol esterase in abiraterone formation was revealed by the decreased AUC of abiraterone by coadministration of orlistat. Orlistat potently inhibited AADAC, implying its potential as a perpetrator of drug-drug interactions. SignificanceAADAC is responsible for the hydrolysis of abiraterone acetate in the intestine and liver, suggesting that concomitant use of abiraterone acetate and drugs potently inhibiting AADAC should be avoided.

Complex of tris(2-hydroxyethyl)amine with zinc bis[(2-methylphenoxy)acetate] as an aortic cholesterol esterase inhibitor in the experiment

Complex of tris(2-hydroxyethyl)amine with zinc bis[(2-methylphenoxy)acetate] as an aortic cholesterol esterase inhibitor in the experiment

Impact of the use of pressurized liquids on the extraction and functionality of proteins and bioactives from brewer’s spent grain

A green methodology based on pressurized liquids (PLE) to extract proteins and obtain highly active extracts from brewer’s spent grain (BSG) is proposed. Box-Behnken experimental design was employed to study the effect of extraction parameters on the protein content (PC), the total phenolic content (TPC), and the antioxidant activity of extracts. Results were compared with those obtained by conventional alkaline extraction assisted with ultrasounds (UAE). The selection of PLE conditions enabled to tailor the PC and TPC of extracts. PLE extracted 36 % more proteins than UAE. PLE extracts showed higher antioxidant, cholesterol esterase inhibition, and ACE inhibitory activities than UAE extract. HPLC-MS/MS enabled to observe that the extraction technique and experimental conditions significantly affected to the kind and amount of extracted proteins, and released peptides, and phenolic compounds. A higher ratio of hydrophobic peptides was observed in PLE extracts, which justified their higher bioactivity.

Pyranocarbazole alkaloids, isolated from Clausena cambodiana leaves, as a pancreatic cholesterol esterase inhibitor, and their HPLC–DAD quantitative determination method

A bioassay-guided isolation method was performed with pancreatic cholesterol esterase as a target enzyme. Four pyranocarbazole alkaloids, 8-hydroxymahanimbine (1), mahanine (2), mahanimbicine (3) and mahanimbine (4) were isolated from Clausena cambodiana Guill leaves for the first time. Furthermore, compound 1 has never before been isolated as a natural product. The chemical structures of the isolated compounds were elucidated by comprehensive spectroscopic analysis, including 1D and 2D-NMR, and comparison with published data. Compounds 1 and 2 exhibited potent inhibitory activity against pancreatic cholesterol esterase, with IC50 values of 48.56 and 34.56 µg/mL, respectively. The HPLC–DAD method for the quantification of four pyranocarbazole alkaloids from C. cambodiana leaves was also validated. The method was simple, accurate, rapid and reliable, and can be used for the quality control of C. cambodiana leaves. Our findings indicate that C. cambodiana leaves could be used as a functional food or pharmaceutical ingredient for the prevention and treatment of hypercholesterolemia.

In silico studies on pancreatic lipase and cholesterol esterase inhibitor 2, 6-di-tert-butyl phenol: A novel molecule for Antiobesity

In silico studies on pancreatic lipase and cholesterol esterase inhibitor 2, 6-di-tert-butyl phenol: A novel molecule for Antiobesity

Identification and molecular docking study of novel cholesterol esterase inhibitory peptides from camel milk proteins

Novel bioactive peptides from camel milk protein hydrolysates (CMPH) were identified and tested for inhibition of cholesterol esterase (CEase), and their possible binding mechanisms were elucidated by molecular docking. Papain-generated CMPH showed the highest degree of hydrolysis. All CMPH produced upon enzymatic degradation demonstrated a dramatic enhancement of CEase inhibition compared with intact camel milk proteins, with papain-generated hydrolysate P9 displaying the highest inhibition. Peptide identification and their modeling through PepSite 2 revealed that among 20 potential bioactive peptides in alcalase-generated hydrolysate A9, only 3 peptides, with sequences KFQWGY, SQDWSFY, and YWYPPQ, showed the highest binding toward CEase catalytic sites. Among 43 peptides in 9-h papain-generated hydrolysate P9, 4 peptides were found to be potent CEase inhibitors. Molecular docking revealed that WPMLQPKVM, CLSPLQMR, MYQQWKFL, and CLSPLQFR from P9 hydrolysates were able to bind to the active site of CEase with good docking scores and molecular mechanics-generalized born surface area binding energies. Overall, this is the first study reporting CEase inhibitory potential of peptides generated from milk proteins.

ω-Phthalimidoalkyl Aryl Ureas as Potent and Selective Inhibitors of Cholesterol Esterase.

Cholesterol esterase (CEase), a serine hydrolase thought to be involved in atherogenesis and thus coronary heart disease, is considered as a target for inhibitor development. We investigated recombinant human and murine CEases with a new fluorometric assay in a structure-activity relationship study of a small library of ω-phthalimidoalkyl aryl ureas. The urea motif with an attached 3,5-bis(trifluoromethyl)phenyl group and the aromatic character of the ω-phthalimide residue were most important for inhibitory activity. In addition, an alkyl chain composed of three or four methylene groups, connecting the urea and phthalimide moieties, was found to be an optimal spacer for inhibitors. The so-optimized compounds 2 [1-(3,5-bis(trifluoromethyl)phenyl)-3-(3-(1,3-dioxoisoindolin-2-yl)propyl)urea] and 21 [1-(3,5-bis(trifluoromethyl)phenyl)-3-(4-(1,3-dioxoisoindolin-2-yl)butyl)urea] exhibited dissociation constants (Ki ) of 1-19 μm on the two CEases and showed either a competitive (2 on the human enzyme and 21 on the murine enzyme) or a noncompetitive mode of inhibition. Two related serine hydrolases-monoacylglycerol lipase and fatty acid amide hydrolase-were inhibited by ω-phthalimidoalkyl aryl ureas to a lesser extent.

Influences of fermentation parameters on lovastatin production by Monascus purpureus using Saccharina japonica as solid fermented substrate

In this study, Saccharina japonica (brown seaweed) was fermented in solid state by Monascus purpureus to maximize lovastatin production, the response surface methodology (RSM) was applied to optimize four different fermentation parameters: temperature (25−35 °C), time (10−20 days), glucose (0.1–1.5%) and peptone (0.1–0.7%) concentration. The predicted combination of process parameters yielding the highest rate of lovastatin production (13.40 mg gdfs−1) was obtained at a temperature of 25.64 °C, a fermentation time of 14.49 days, glucose concentration of 1.32% and peptone concentration of 0.20%, with 92.85% validity. Among the studied factors, glucose, incubation time and temperature most strongly influenced lovastatin production. Triplicate experiments in which lovastatin was produced under optimal conditions resulted in a mean yield of 13.98 mg gdfs−1 with 207.84 mg gdfs−1 biomass. Liquid chromatography–tandem mass spectrometry (quadrupole time-of-flight) analysis confirmed the ionic molecular weight of lovastatin (405.26). Lovastatin from the M. purpureus fermented S. japonica exhibited thermal stability, superoxide dismutase activity and a cholesterol esterase inhibition activity that was higher than that of unfermented sample and showed no toxic effect on Caco-2 cell. Thus, S. japonica was a suitable substrate to maximize lovastatin production from M. purpureus at optimum condition for applying in food and pharmaceutical industry.

5,6-Benzoflavones as cholesterol esterase inhibitors: synthesis, biological evaluation and docking studies.

In a continued effort to develop potent cholesterol esterase (CEase) inhibitors, a series of 5,6-benzoflavone derivatives was rationally designed and synthesized by changing the position of the benzene ring attached to the flavone skeleton in previously reported 7,8-benzoflavones. All the synthesized compounds were checked for their inhibitory potential against cholesterol esterase (CEase) using a spectrophotometric assay. Among the series of forty compounds, seven derivatives (B-10 to B-16) exhibited above 90 percent inhibition against CEase in an in vitro enzymatic assay. Compound B-16 showed the most promising activity with an IC50 value of 0.73 nM against cholesterol esterase. To determine the type of inhibition, enzyme kinetic studies were carried out for B-16, which revealed its mixed-type inhibition approach. Moreover, to figure out the key binding interactions of B-16 with the amino acid residues of the enzyme's active site, molecular protein-ligand docking studies were also performed. B-16 completely blocks the catalytic assembly of CEase and prevents it from participating in the ester hydrolysis mechanism. The favorable binding conformation of B-16 suggests its prevailing role as a CEase inhibitor. Overall, the study showed that the cis-orientation of ring A with respect to the carbonyl group of ring C is responsible for the potent CEase inhibitory activity of the newly synthesized compounds.

Benzoflavones as cholesterol esterase inhibitors: Synthesis, biological evaluation and docking studies

A library of forty 7,8-benzoflavone derivatives was synthesized and evaluated for their inhibitory potential against cholesterol esterase (CEase). Among all the synthesized compounds seven benzoflavone derivatives (A-7, A-8, A-10, A-11, A-12, A-13, A-15) exhibited significant inhibition against CEase in in vitro enzymatic assay. Compound A-12 showed the most promising activity with IC50 value of 0.78nM against cholesterol esterase. Enzyme kinetic studies carried out for A-12, revealed its mixed-type inhibition approach. Molecular protein–ligand docking studies were also performed to figure out the key binding interactions of A-12 with the amino acid residues of the enzyme’s active site. The A-12 fits well at the catalytic site and is stabilized by hydrophobic interactions. It completely blocks the catalytic assembly of CEase and prevents it to participate in ester hydrolysis mechanism. The favorable binding conformation of A-12 suggests its prevailing role as CEase inhibitor.