Higher Angiotensin-converting Enzyme Research Articles

Production of Fish Protein Hydrolysates from Scyliorhinus canicula Discards with Antihypertensive and Antioxidant Activities by Enzymatic Hydrolysis and Mathematical Optimization Using Response Surface Methodology.

Fish discards are of major concern in new EU policies. Alternatives for the management of the new biomass that has to be landed is compulsory. The production of bioactive compounds from fish protein hydrolysates (FPH) has been explored in recent years. However, the viability of Scyliorhinus canicula discards, which might account for up to 90–100% of captures in mixed trawler, gillnet, and longline industrial fisheries, to produce FPH from the muscle with bioactivities has still not been studied in terms of the optimization of the experimental conditions to enhance its production. The effect of pH and temperature on the hydrolysis of the S. canicula muscle was mediated by three commercial proteases using response surface methodology. Temperatures of 64.6 °C and 60.8 °C and pHs of 9.40 and 8.90 were established as the best hydrolysis conditions for Alcalase and Esperase, respectively. Optimization of the best conditions for the maximization of antihypertensive and antioxidant activities was performed. Higher Angiotensin-converting enzyme (ACE) activity was found with Esperase. The pH optimum and temperature optimum for antioxidants were 55 °C/pH8.0 for ABTS/DPPH-Esperase, 63.1 °C/pH9.0 for DPPH-Alcalase, and 55 °C/pH9.0 for ABTS-Alcalase. No hydrolysis was detected when using Protamex.

ACE-modulated adiposity is related to higher energy expenditure and independent of lipolysis and glucose incorporation into lipids in adipocytes.

Emerging evidence suggests that both systemic and white adipose tissue-renin-angiotensin system components influence body weight control. We previously demonstrated that higher angiotensin-converting enzyme (ACE) gene expression is associated with lower body adiposity in a rodent model. In this study, we tested the hypothesis that a higher ACE gene dosage reduces fat accumulation by increasing energy expenditure and modulating lipolysis and glucose incorporation into lipids in adipocytes. After a 12 wk follow-up period, transgenic mice harboring three ACE (3ACE) gene copies displayed diminished WAT mass, lipid content in their carcasses, adipocyte hypotrophy, and higher resting oxygen uptake (V̇o2) in comparison with animals with one ACE gene copy (1ACE) after long fasting (12 h). No differences were found in food intake and in the rates of lipolysis and glucose incorporation into lipids in adipocytes. To assess whether this response involves increased angiotensin II type I receptor (AT1R) activation, AT1R blocker (losartan) was used in a separate group of 3ACE mice with body weight and adiposity comparable to that in the other 3ACE animals. We suggest that fasting-induced lower adiposity observed in animals with 3ACE gene copies might be associated with a higher expense of energy reserves; this response did not involve AT1R activation.

Graphitized Porous Carbon for Rapid Screening of Angiotensin-Converting Enzyme Inhibitory Peptide GAMVVH from Silkworm Pupa Protein and Molecular Insight into Inhibition Mechanism.

A novel hydrophobic hexapeptide with high angiotensin-converting enzyme (ACE) inhibitory activity was screened from silkworm pupa protein (SPP) hydrolysate via graphitized porous carbon and reverse-phase high-performance liquid chromatography methods. Graphitized porous carbon derived from dopamine, possessing high surface area and high graphitic carbon, was used to rapidly screen and enrich hydrophobic peptides from SPP hydrolysate. The ACE inhibition pattern and mechanism of the purified peptide were also systematically studied by the classic Lineweaver-Burk model and by molecular docking/dynamic simulation. The novel hydrophobic hexapeptide was identified as Gly-Ala-Met-Val-Val-His (GAMVVH, IC50 = 19.39 ± 0.21 μM) with good thermal/antidigestive stabilities. Lineweaver-Burk plots revealed that GAMVVH behaved as a competitive ACE inhibitor. It formed hydrogen bonds with S1 and S2 pockets of ACE and established competitive coordination with Zn(II) of ACE. The synergy of hydrogen bonds with active pockets and Zn(II) coordination efficiently changed the three-dimensional structure of ACE and thus inhibited bioactivity of ACE.

Peptide identification in a salmon gelatin hydrolysate with antihypertensive, dipeptidyl peptidase IV inhibitory and antioxidant activities

Salmon gelatin (Salmo salar, SG) enzymatic hydrolysates were generated using Alcalase 2.4L, Alcalase 2.4L in combination with Flavourzyme 500L, Corolase PP, Promod 144MG and Brewer's Clarex. The hydrolysate generated with Corolase PP for 1h (SG-C1) had the highest angiotensin converting enzyme (ACE, IC50=0.13±0.05mgmL−1) and dipeptidyl peptidase IV (DPP-IV, IC50=0.08±0.01mgmL−1) inhibitory activities, and oxygen radical absorbance capacity (ORAC, 540.94±9.57μmolTEg−1d.w.). The in vitro bioactivities of SG-C1 were retained following simulated gastrointestinal digestion. Administration of SG and SG-C1 (50mgkg−1 body weight) to spontaneously hypertensive rats (SHR) lowered heart rate along with systolic, diastolic and mean arterial blood pressure. The SG-C1 hydrolysate was fractionated using semi-preparative RP-HPLC and the fraction with highest overall in vitro bioactivity (fraction 25) was analysed by UPLC-MS/MS. Four peptide sequences (Gly-Gly-Pro-Ala-Gly-Pro-Ala-Val, Gly-Pro-Val-Ala, Pro-Pro and Gly-Phe) and two free amino acids (Arg and Tyr) were identified in this fraction. These peptides and free amino acids had potent ACE and DPP-IV inhibitory, and ORAC activities. The results show that SG hydrolysates have potential as multifunctional food ingredients particularly for the management of hypertension.

Genetic variation in angiotensin converting-enzyme affects the white matter integrity and cognitive function of amnestic mild cognitive impairment patients

Angiotensin-converting enzyme (ACE) gene has been implicated in amnestic mild cognitive impairment (aMCI). Most human genetic studies have focused on ACE insertion (I)/deletion (D) polymorphism and yielded conflicting results. In this work, we evaluated the relationships between cognitive function, serum ACE level, brain white matter (WM) integrity, and ACE I/D polymorphism in 48 patients with aMCI and 36 well matched control subjects from south China. In aMCI patients, D allele frequency was higher (D/I ratio=0.51:0.49) than that of the control subjects (D/I ratio=0.43:0.57); however, the difference was not statistically significant (p>0.05). The D carriers in aMCI subjects performed significantly poorer on auditory–verbal learning test (AVLT) -delayed recall than the I homozygous group (p=0.035). These carriers had higher serum ACE level than the I homozygous carriers of aMCI (p=0.037). In the aMCI group, D carriers showed significantly lower fractional anisotropy (FA) values in the left middle frontal gyrus, left anterior cingulate, right gyrus parahippocampalis, right inferior parietal lobule, and bilateral anterior central gyrus than the I homozygotes carriers. However, no significant difference was observed in FA values between I homozygotes and D carriers in the control subjects. The ACE D allele in aMCI patients may increase the risk of cognitive impairment. A high serum ACE level possibly plays an important role in the incidence of aMCI.

Production and identification of antioxidant and angiotensin-converting enzyme inhibition and dipeptidyl peptidase IV inhibitory peptides from bighead carp (Hypophthalmichthys nobilis) muscle hydrolysate

We investigated bioactive peptides obtained from muscle protein hydrolysate of bighead carp by evaluating in vitro dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibitory capacities and antioxidant activity. Peptide sequences were identified from pepsin hydrolysates. Met-Lys-Ala-Val-Cys-Phe-Ser-Leu was one of the most effective sequences with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC50=4.58±0.15μM) and relatively high ACE inhibitory capacity (IC50=3.68±0.13μM). Tyr-Asn-Leu-Lys-Glu-Arg-Tyr-Ala-Ala-Trp (IC50=1.35±0.23μM) and Tyr-Asn-Arg-Leu-Pro-Glu-Leu (IC50=3.42±0.39μM) exhibited the most potent ACE inhibitory activity. Ile-Ala-Asp-His-Phe-Leu showed the highest DPP-IV inhibitory activity with an IC50 value of 610.1±82.6μM. All selected peptides were non-toxic, and most were non-allergenic according to in silico predictions. These results indicate the promising potential of bighead carp muscle hydrolysates as functional additives in foods and pharmaceuticals.

Angiotensin converting enzyme serum activities: Relationship with Alzheimer’s disease

ObjectiveTo determine serum activities of angiotensin-converting enzyme (ACE) as a marker in diagnosis and determine the severity of Alzheimer's disease (AD), MethodsWe measured serum ACE activities in 59 moderate-severe AD, 19 mild AD, 45 amnestic mild cognitive impairment (aMCI) and 39 controls. ResultsWe found that patients in moderate-severe AD stages showed significantly higher ACE in comparison to aMCI and controls (ANOVA, LSD post hoc test: p: 0.02 and p: 0.01, respectively). Logistic regression analysis showed that if ACE activities added 200 U/L, the superiority of AD risk was 1.18 times higher than before compared with the control group (OR 1.18, 95% CI 1.01–1.74; P=0.49). By means of multivariate linear regression analysis, we found that age (β coefficient: 7.77; P: 0.01) was significantly associated with ACE activities. However, ACE activities were found to be significantly negatively associated with measures of orientation and immediate recall among the AD patients (r<0, P<0.05), whereas ACE activities were not associated with any MMSE scores among the non-AD groups (P > 0.05).uuuu ConclusionsACE serum activity that correlates with age is likely to constitute a potential risk factor for the development of AD. ACE serum activity might be a useful biomarker for disease status with increasingly high ACE from mild stage to moderate-severe stage. Moreover, patients with aMCI could take ACE inhibitor (ACEI) to decrease the incidence of AD, and patients with AD could take ACEI to retard cognitive decline in early AD.

Cirrhosis Related to Hepatic Sarcoidosis in Older Adults

Cirrhosis Related to Hepatic Sarcoidosis in Older Adults

Potential of Plant’s Dipeptidyl Peptidase I &amp; II Homologs in Generation of ACE Inhibitory Peptides

Synthetic inhibitors of angiotensin converting enzyme (ACE) are commonly used in the treatment of hypertension and other cardiovascular diseases. But their diverse side effects stipulated nontoxic safer and economic inhibitors which can be accomplished by using peptidyl inhibitors from natural sources or functional food ingradients. Dipeptidyl peptidases cleaved dipeptide moieties from amino terminus of oligopepides so, they may be used to generate effective dipeptidyl ACE inhibitors. In present study, role of purified DPP-I and II in generation of ACE inhibitors have been explored. Results showed that collagen alpha-1(III) from chicken showed highest ACE inhibitory potential. Both dipeptidyl peptidases hydrolysed various potent inhibitory dipeptides from their oligopeptide precursors. In addition, sequential digestion of proteins with trypsin, DPP-I and II released approximate 15 % of total inhibitory peptides. Furthermore, inhibitory peptide concentration can be increased up to 30 % or more by using more proteases in presence of DPP-I and II. Results revealed that both DPP-I and II possesses the ability to generate ACE dipeptide inhibitors from oligopeptides. Still various dipeptidyl inhibitory peptides remained in generating oligopeptides, which required study of other endopeptidases with broad specificities.

Protein Kinase C-δ Mediates Shedding of Angiotensin-Converting Enzyme 2 from Proximal Tubular Cells.

Angiotensin-converting enzyme 2 (ACE2) degrades angiotensin (Ang) II to Ang-(1–7), and protects against diabetic renal injury. Soluble ACE2 fragments are shed from the proximal tubule, and appear at high levels in the urine with diabetes. High glucose-induced shedding of ACE2 from proximal tubular cells is mediated by the enzyme “a disintegrin and metalloproteinase-17″ (ADAM17). Here, we investigated the mechanism for constitutive shedding of ACE2. Mouse proximal tubular cells were cultured and ACE2 shedding into the media was assessed by enzyme activity assay and immunoblot analysis. Cells were incubated with pharmacologic inhibitors, or transfected with silencing (si) RNA. Incubation of proximal tubular cells with increasing concentrations of D-glucose stimulated ACE2 shedding, which peaked at 16 mM, while L-glucose (osmotic control) had no effect on shedding. In cells maintained in 7.8 mM D-glucose, ACE2 shedding was significantly inhibited by the pan-protein kinase C (PKC) competitive inhibitor sotrastaurin, but not by an inhibitor of ADAM17. Incubation of cells with the PKC-α and -β1-specific inhibitor Go6976, the PKC β1 and β2-specific inhibitor ruboxistaurin, inhibitors of matrix metalloproteinases-2,-8, and -9, or an inhibitor of ADAM10 (GI250423X) had no effect on basal ACE2 shedding. By contrast, the PKC-δ inhibitor rottlerin significantly inhibited both constitutive and high glucose-induced ACE2 shedding. Transfection of cells with siRNA directed against PKC-δ reduced ACE2 shedding by 20%, while knockdown of PKC-ε was without effect. These results indicate that constitutive shedding of ACE2 from proximal tubular cells is mediated by PKC-δ, which is also linked to high glucose-induced shedding. Targeting PKC-δ may preserve membrane-bound ACE2 in proximal tubule in disease states and diminish Ang II-stimulated adverse signaling.

In Vitro and In Vivo Assessment of Angiotensin-Converting Enzyme (ACE) Inhibitory Activity of Fermented Soybean Milk by Lactobacillus casei Strains.

Angiotensin-converting enzyme (ACE) inhibitory activity of fermented soybean milk (FSM) by Lactobacillus casei strains in vitro was investigated in this study. Effects of fermented soybean milk administration by gavage on systolic blood pressure and diastolic blood pressure was also evaluated in spontaneously hypertensive rats (SHR) rats and Wistar-Kyoto (WKY) rats. Results showed that, CICC 20280 and CICC 23184 FSM showed high ACE inhibitory activity in vitro test and ACE inhibitory activity of CICC 23184 FSM was higher than CICC 20280 FSM. The bioactive substances of FSM were peptide and γ-aminobutyric acid (GABA). Their contents in CICC 20280 FSM and CICC 23184 FSM were 3.97±0.67mg/ml (peptide), 1.71±0.36mg/ml (GABA) and 5.17±0.22mg/ml (peptide), 1.57±0.21mg/ml (GABA), respectively. Moreover, CICC 20280 and CICC 23184 FSM administration by gavage could effectively lower the blood pressure of SHR to a normal level, while there was no effect on blood pressure of WKY rats. This result indicated that the bioactive substances could play an antihypertensive role when the blood pressure was not within the normal levels (high levels).

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides

Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of>500mg/100ml after 72h of incubation at 35°C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC50 were<1mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

Simultaneous Rho kinase inhibition in circulating leukocytes and in cardiovascular tissue in rats with high angiotensin converting enzyme levels

BackgroundThe small guanosine triphosphatase RhoA and its direct target Rho kinase (ROCK) play important roles in cardiovascular pathophysiology. Activated ROCK phosphorylates intracellular proteins with detrimental effects on cardiovascular remodeling. Increased ROCK activity in circulating leukocytes is observed in hypertension and in heart failure, but its relationship with ROCK activation in the myocardium and vessels is unknown. We hypothesized that ROCK activation and phosphorylation/activation of some of its key downstream molecules in the heart and arterial wall are reflected in circulating leukocytes. MethodsPhosphorylation of MYPT1, ERM and p38-MAPK and levels of p65-NF-κB were determined in the left ventricle (LV), aortic wall and circulating leukocytes in rats with high (Brown Norway, BN) and low (Lewis) angiotensin converting enzyme. A group of BN rats received the ROCK inhibitor fasudil (7days). ResultsCompared to Lewis rats, in the BN group phosphorylated levels of MYPT1, ERM and p38-MAPK and levels of p65-NF-κB were increased (P<0.05) in the LV (67%, 92%, 52% and 98%, respectively); in the aortic wall (57%, 51%, 68% and 66%, respectively) and in circulating leukocytes (61%, 72%, 49% and 105%, respectively). Fasudil reduced all these levels to those observed in Lewis rats. Phosphorylated MYPT1, ERM, and p38-MAPK and levels of p65-NF-κB in circulating leukocytes were significantly correlated with their respective LV and aortic wall levels (excepting p65-NF-κB in aorta). ConclusionROCK activity in circulating leukocytes reflects activation of this signaling pathway in the myocardium and aortic wall in this model, and supports its value as a potential cardiovascular remodeling marker.

Antioxidant and ACE Inhibitory Bioactive Peptides Purified from Egg Yolk Proteins.

Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF). Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS) in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y) and tryptophan (W), in sequences identified by LC-MS as WYGPD (EYGF-23) and KLSDW (EYGF-33), contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56) was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69%) and IC50 value (3.35 mg/mL). The SDNRNQGY peptide (10 mg/mL) had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL). In addition, YPSPV in (EYGF-33) (10 mg/mL) had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk.

Simultaneous Determination of 8 Small Antihypertensive Peptides with Tyrosine at the C-Terminal inLaminaria japonicaHydrolysates by RP-HPLC Method

A simple and efficient RP high-performance liquid chromatography method was developed for simultaneous analysis of eight small antihypertensive peptides with tyrosine at the C-terminal in Laminaria japonica hydrolysates (LHs). The chromatography was performed on an Xterra MS-C18 column at 45C, with an aqueous mobile phase (0.1% trifluoroacetic acid, pH 2.8) acetonitrile in a linear gradient at the flow rate of 0.7 mL/min, and detected at 218 nm. The detection limits ranged from 0.0624 to 0.2365 μM. Correlation coefficients were greater than 0.9997. The recovery ranged from 92.17 to 120.08%. The small peptides were successfully determined by this method in LHs and the structures were confirmed by ESI-MS/MS, and the structure–activity relationships were discussed. The results demonstrated that the proposed method could be used to determine the peptides with tyrosine at the C-terminal, and to characterize a widespread detection mode for small peptide analysis in easy operation and low cost. Practical Applications This study is the first to report that marine Laminaria japonica protein hydrolyzed by combined enzymes of the alcalase, trypsin and papain displayed high angiotensin-converting enzyme (ACE) inhibitory activity. An effective and efficient reverse phase (RP) high-performance liquid chromatography method was developed for simultaneous analysis of eight small antihypertensive peptides with tyrosine at the C-terminal. Adopting the proposed method, Laminaria japonica hydrolysates and the ACE inhibitory activities of small peptides will be successfully analyzed. The results also demonstrated that Laminaria japonica proteins would be a good source of hypotensive peptides.

Diagnostic Utility of Angiotensin-Converting Enzyme in Sarcoidosis: A Population-Based Study.

Sarcoidosis is a disease with heterogenous clinical presentations. Diagnosis of sarcoidosis is often challenging with the lack of gold standard tests. In this study, we investigated the diagnostic utility of angiotensin-converting enzyme (ACE) for diagnosis of sarcoidosis. A cohort of Olmsted County, Minnesota residents who were diagnosed with sarcoidosis between January 1, 1984 and December 31, 2013 was identified based on individual medical record review. ACE levels recorded in the medical records of all subjects at the time of diagnosis were extracted. Comparator subjects were residents of Olmsted County, Minnesota who had ACE levels tested the same time period but did not have a diagnosis of sarcoidosis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the c-statistic of high versus low/normal ACE to diagnose sarcoidosis were calculated. A total of 3277 Olmsted County residents age ≥18 years had at least one ACE test in 1984-2013. The sarcoidosis incidence cohort contained 295 Olmsted County residents diagnosed with sarcoidosis in 1984-2013. Of these, ACE tests were obtained in 251. The sensitivity and specificity of high ACE for diagnosis of sarcoidosis were 41.4 % (95 % CI 35.3-47.8 %) and 89.9 % (95 % CI 88.8-91.0 %), respectively. The PPV and NPV in this population were 25.4 % (95 % CI 21.3-29.9 %) and 94.9 % (95 % CI 85.0-87.4 %). This study demonstrated a poor sensitivity and insufficient specificity of high ACE for diagnosis of sarcoidosis suggesting a limited role of ACE in clinical practice.

Angiotensin Converting Enzyme Inhibitor Dialyzability and Outcomes in Older Patients Receiving Hemodialysis

Background/Aims: Some angiotensin converting enzyme (ACE) inhibitors are efficiently removed from circulation by hemodialysis (‘high dialyzability'), whereas others are not (‘low dialyzability'). In patients receiving hemodialysis, this may influence the effectiveness of ACE inhibitors. Methods: Using linked healthcare databases we identified older patients receiving chronic hemodialysis who filled new ACE inhibitor prescriptions. The low dialyzability group (n = 3,369) included fosinopril and ramipril. The high dialyzability group (n = 5,974) included enalapril, lisinopril, and perindopril. The primary outcome was all-cause mortality within 180 days of first ACE inhibitor prescription. Results: There were 361 deaths among 5,974 patients (6.0%) prescribed with low dialyzability ACE inhibitors and 179 deaths among 3,369 patients (5.3%) prescribed with high dialyzability ACE inhibitors (relative risk 1.1, 95% CI 0.9-1.3, p = 0.6). Conclusion: In this study of older patients receiving hemodialysis, the dialyzability of ACE inhibitors was not associated with mortality or cardiovascular outcomes.

Angiotensin-converting enzyme (ACE) inhibitory potential of standardized Mucuna pruriens seed extract

Context: Mucuna pruriens Linn. (Fabaceae) is a tropical legume, traditionally used for controlling blood pressure. Inhibition of angiotensin-converting enzyme (ACE) is one of the successful strategies for controlling hypertension.Objective: The present study evaluated the ACE inhibition potential of the standardized extract of M. pruriens seeds.Materials and methods: Standardization of the extract and its fractions were carried out by RP-HPLC method [methanol and 1% v/v acetic acid in water (5:95 v/v)] using levodopa as a marker. The ACE inhibition activity of the extract and fractions was evaluated at different concentrations (20, 40, 60, 80, and 100 µg/mL) using the HPLC-DAD and the UV spectrophotometric method. The liberation of hippuric acid (HA) from hippuryl-l-histidyl-l-leucine (HHL) was estimated in the spectrophotometric method and RP-HPLC assay at 228 nm.Results: Methanol extract and aqueous fraction showed a maximum activity with IC50 values of 38.44 ± 0.90 and 57.07 ± 2.90 µg/mL (RP-HPLC), and 52.68 ± 2.02 and 67.65 ± 2.40 µg/mL (spectrophotometry), respectively.Discussion: The study revealed that the aqueous extract contains the highest amount of levodopa. Eventually the methanol extract showed highest ACE inhibition activity except levodopa alone. It was further observed that the inhibition was altered with respect to the change in the content of levodopa in the extract. Thus, it can be assumed that levodopa may be responsible for the ACE inhibition activity of M. pruriens seeds.Conclusion: It can be concluded that M. pruriens seed is a potential ACE inhibitor can be explored further as an effective antihypertensive agent.

Angiotensin-Converting Enzyme and Aldosterone Serum Levels as Prognostic and Predictive Biomarkers for Cediranib in NCIC Clinical Trials Group Study BR.24

BackgroundTreatment-induced hypertension might correlate with antiangiogenesis treatment efficacy. We evaluated the prognostic and predictive significance of angiotensin-converting enzyme (ACE) and aldosterone serum levels, regulators of blood pressure, in patients with advanced non–small-cell lung cancer (NSCLC) enrolled in the NCIC Clinical Trials Group BR.24 trial. Results of BR.24 demonstrated marginal efficacy of cediranib (an inhibitor of vascular endothelial growth factor receptors) combination with carboplatin-paclitaxel. Patients and MethodsACE and aldosterone were measured retrospectively using enzyme-linked immunosorbent assays at baseline and at time of treatment in serum samples of 226 and 176 of 296 enrolled patients, respectively. Cox regression was performed to correlate biomarkers and patient characteristics with overall survival (OS) and progression-free survival. ResultsPatients who received placebo with high baseline ACE levels (> 115 ng/mL) had significantly better OS compared with patients with low ACE (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.31-0.78; P = .002). Low ACE levels (≤ 115 ng/mL) were predictive of OS benefit from cediranib (P = .05). Aldosterone changes with treatment predicted differential OS between treatment arms, with an increased trend to associate with longer OS (HR, 0.49; 95% CI, 0.23-1.06; P = .07) for patients who received cediranib, but shorter OS (HR, 1.90; 95% CI, 0.93-3.87; P = .08) for patients who received placebo (interaction P = .01). ConclusionLow baseline ACE levels were prognostic of poor OS and predictive of OS benefit from cediranib. An aldosterone level increase with treatment might also be predictive of OS benefit from cediranib. These biomarkers should be validated in additional antiangiogenic trials in NSCLC and other cancers.

Optimization of Hydrolysis Conditions for Production of Angiotensin-Converting Enzyme Inhibitory Peptides from Basa Fish Skin Using Response Surface Methodology

ABSTRACTBasa fish skin free from fat and noncollagenous proteins was hydrolyzed by different proteinases to produce angiotensin-converting enzyme (ACE) inhibitory peptides. Protamex hydrolysates were found to have the highest ACE inhibitory activity. Response surface methodology (RSM) was applied to optimize the hydrolysis conditions of Protamex—including enzyme-to-substrate ratio, hydrolysis time, and solid (fish skin)-to-liquid (water for hydrolysis)—at a temperature of 50°C and a pH of 7.0. The mathematical model demonstrated a good fit with the experimental data. An enzyme-to-substrate ratio of 6,108 U/g, a hydrolysis time of 1.24 h, and a solid-to-liquid ratio of 1:8.05 g/mL were found to be the optimal conditions to achieve the highest value of ACE inhibitory activity. The IC50 of the hydrolysates for ACE inhibitory activity was 1.417 mg/mL under these conditions.