The ACE inhibitor captopril inhibits ACN-1 to control dauer formation and aging.

The renin-angiotensin-aldosterone system (RAAS) plays a well-characterized role regulating blood pressure in mammals. Pharmacological and genetic manipulation of the RAAS has been shown to extend lifespan in Caenorhabditis elegans, Drosophila and rodents, but its mechanism is not well defined. Here, we investigate the angiotensin-converting enzyme (ACE) inhibitor drug captopril, which extends lifespan in worms and mice. To investigate the mechanism, we performed a forward genetic screen for captopril-hypersensitive mutants. We identified a missense mutation that causes a partial loss of function of the daf-2 receptor tyrosine kinase gene, a powerful regulator of aging. The homologous mutation in the human insulin receptor causes Donohue syndrome, establishing these mutant worms as an invertebrate model of this disease. Captopril functions in C. elegans by inhibiting ACN-1, the worm homolog of ACE. Reducing the activity of acn-1 via captopril or RNA interference promoted dauer larvae formation, suggesting that acn-1 is a daf gene. Captopril-mediated lifespan extension was abrogated by daf-16(lf) and daf-12(lf) mutations. Our results indicate that captopril and acn-1 influence lifespan by modulating dauer formation pathways. We speculate that this represents a conserved mechanism of lifespan control.

SARS-CoV-2 induces cardiomyocyte apoptosis and inflammation but can be ameliorated by ACE inhibitor Captopril.

Although the clinical manifestation of COVID-19 is mainly respiratory symptoms, approximately 20% of patients suffer from cardiac complications. COVID-19 patients with cardiovascular disease have higher severity of myocardial injury and poor outcomes. The underlying mechanism of myocardial injury caused by SARS-CoV-2 infection remains unclear. Using a non-transgenic mouse model infected with Beta variant (B.1.351), we found that the viral RNA could be detected in lungs and hearts of infected mice. Pathological analysis showed thinner ventricular wall, disorganized and ruptured myocardial fiber, mild inflammatory infiltration, and mild epicardia or interstitial fibrosis in hearts of infected mice. We also found that SARS-CoV-2 could infect cardiomyocytes and produce infectious progeny viruses in human pluripotent stem cell-derived cardiomyocyte-like cells (hPSC-CMs). SARS-CoV-2 infection caused apoptosis, reduction of mitochondrial integrity and quantity, and cessation of beating in hPSC-CMs. In order to dissect the mechanism of myocardial injury caused by SARS-CoV-2 infection, we employed transcriptome sequencing of hPSC-CMs at different time points after viral infection. Transcriptome analysis showed robust induction of inflammatory cytokines and chemokines, up-regulation of MHC class I molecules, activation of apoptosis signaling and cell cycle arresting. These may cause aggravate inflammation, immune cell infiltration, and cell death. Furthermore, we found that Captopril (hypotensive drugs targeting ACE) treatment could alleviate SARS-CoV-2 induced inflammatory response and apoptosis in cardiomyocytes via inactivating TNF signaling pathways, suggesting Captopril may be beneficial for reducing COVID-19 associated cardiomyopathy. These findings preliminarily explain the molecular mechanism of pathological cardiac injury caused by SARS-CoV-2 infection, providing new perspectives for the discovery of antiviral therapeutics.

A novel nanoluciferase transgenic reporter measures proteinuria in zebrafish.

The zebrafish is an important animal system for modeling human diseases. This includes kidney dysfunction as the embryonic kidney (pronephros) shares considerable molecular and morphological homology with the human nephron. A key clinical indicator of kidney disease is proteinuria, but a high-throughput readout of proteinuria in the zebrafish is currently lacking. To remedy this, we used the Tol2 transposon system to generate a transgenic zebrafish line that uses the fabp10a liver-specific promoter to over-express a nanoluciferase molecule fused with the D3 domain of Receptor-Associated Protein (a type of molecular chaperone) which we term NL-D3. Using a luminometer, we quantified proteinuria in NL-D3 zebrafish larvae by measuring the intensity of luminescence in the embryo medium. In the healthy state, NL-D3 is not excreted, but when embryos were treated with chemicals that affected either proximal tubular reabsorption (cisplatin, gentamicin) or glomerular filtration (angiotensin II, Hanks Balanced Salt Solution, Bovine Serum Albumin), NL-D3 is detected in fish medium. Similarly, depletion of several gene products associated with kidney disease (nphs1, nphs2, lrp2a, ocrl, col4a3, and col4a4) also induced NL-D3 proteinuria. Treating col4a4 depleted zebrafish larvae (a model of Alport syndrome) with captopril reduced proteinuria in this system. Thus, our findings validate the use of the NL-D3 transgenic zebrafish as a robust and quantifiable proteinuria reporter. Hence, given the feasibility of high-throughput assays in zebrafish, this novel reporter will permit screening for drugs that ameliorate proteinuria, thereby prioritizing candidates for further translational studies.

Captopril, a Renin-Angiotensin System Inhibitor, Attenuates Tumour Progression in the Regenerating Liver Following Partial Hepatectomy.

(1) Liver regeneration following partial hepatectomy for colorectal liver metastasis (CRLM) has been linked to tumour recurrence. Inhibition of the renin−angiotensin system (RASi) attenuates CRLM growth in the non-regenerating liver. This study investigates whether RASi exerts an antitumour effect within the regenerating liver following partial hepatectomy for CRLM and examines RASi-induced changes in the tumour immune microenvironment; (2) CRLM in mice was induced via intrasplenic injection of mouse colorectal tumour cells, followed by splenectomy on Day 0. Mice were treated with RASi captopril (250 mg/kg/day), or saline (control) from Day 4 to Day 16 (endpoint) and underwent 70% partial hepatectomy on Day 7. Liver and tumour samples were characterised by flow cytometry and immunofluorescence; (3) captopril treatment reduced tumour burden in mice following partial hepatectomy (p < 0.01). Captopril treatment reduced populations of myeloid-derived suppressor cells (MDSCs) (CD11b+Ly6CHi p < 0.05, CD11b+Ly6CLo p < 0.01) and increased PD-1 expression on infiltrating hepatic tissue-resident memory (TRM)-like CD8+ (p < 0.001) and double-negative (CD4-CD8-; p < 0.001) T cells; (4) RASi reduced CRLM growth in the regenerating liver and altered immune cell composition by reducing populations of immunosuppressive MDSCs and boosting populations of PD-1+ hepatic TRMs. Thus, RASi should be explored as an adjunct therapy for patients undergoing partial hepatectomy for CRLM.

Captopril and Spironolactone can Attenuate Diabetic Nephropathy in Wistar Rats by Targeting ABCA1 and microRNA-33.

BACKGROUND: Nephropathy diabetes is one of the important causes of death and a more prevalent cause of end-stage renal disease. OBJECTIVE: The present study investigated the effect of applying spironolactone and captopril and their combination on some renal performance indices and cholesterol-efflux-related gene expression in nephropathy diabetic rats. METHODS: Intraperitoneal injection of streptozotocin was used to induce diabetes in rats. FBS, creatinine, and BUN were assayed using the calorimetry technique; also, urine microalbumin was assayed by ELISA. Hepatic gene expressions of ABCA1, ABCG1, and miR-33 were evaluated by the real-time PCR method. RESULTS: FBS levels in the captopril-treated group were significantly decreased compared with the untreated diabetic group. BUN levels of treated groups with captopril and a combination of captopril + spironolactone were significantly increased. GFR of both treated diabetic groups with captopril and spironolactone was significantly lower than an untreated diabetic group. ABCA1 gene expression in hepatic cells of the combination of spironolactone + captopril treated group was significantly increased compared to other treated and untreated diabetic groups. The hepatic expression of the ABCG1 gene in the treated and untreated diabetic groups was significantly lower than in the control group. Treatment of the diabetic group with only combination therapy decreased the hepatic gene expression of miR-33 significantly. CONCLUSION: Obtained results suggest that S+C combination therapy can improve nephropathy and diabetes disorders by targeting the ABCA1 and miR-33 gene expression. It is suggested that miR-33 and ABCA1 genes evaluation could be a new therapeutic strategy for nephropathy diabetes remediation.

Captopril related kidney damage: renal afferent arteriolar responses to angiotensin II and inflammatory signaling.

Captopril can have nephrotoxic effects, which are largely attributed to accumulated renin and "escaped" angiotensin II (Ang II). Here we test whether angiotensin converting enzyme-1 (ACE1) inhibition damages kidneys via alteration of renal afferent arteriolar responses to Ang II and inflammatory signaling. C57Bl/6 mice were given vehicle or captopril (60 mg/kg per day) for four weeks. Hypertension was obtained by minipump supplying Ang II (400 ng/kg per min) during the second 2 weeks. We assessed kidney histology by periodic acid-Schiff (PAS) and Masson staining, glomerular filtration rate (GFR) by FITC-labeled inulin clearance, and responses to Ang II assessed in afferent arterioles in vitro. Moreover, arteriolar H2O2 and catalase, plasma renin were assayed by commercial kits, and mRNAs of renin receptor, transforming growth factor-ß (TGF-ß) and cyclooxygenase-2 (COX-2) in the renal cortex, mRNAs of angiotensin receptor-1 (AT1R) and AT2R in the preglomerular arterioles were detected by RT-qPCR. The results showed that, compared to vehicle, mice given captopril showed lowered blood pressure, reduced GFR, increased plasma renin, renal interstitial fibrosis and tubular epithelial vacuolar degeneration, increased expression of mRNAs of renal TGF-ß and COX-2, decreased production of H2O2 and increased catalase activity in preglomerular arterioles and enhanced afferent arteriolar Ang II contractions. The latter were blunted by incubation with H2O2. The mRNAs of renal microvascular AT1R and AT2R remained unaffected by captopril. Ang II-infused mice showed increased blood pressure and reduced afferent arteriolar Ang II responses. Administration of captopril to the Ang II-infused mice normalized blood pressure, but not arteriolar Ang II responses. We conclude that inhibition of ACE1 enhances renal microvascular reactivity to Ang II and may enhance important inflammatory pathways.

Tidal Volume-Dependent Activation of the Renin-Angiotensin System in Experimental Ventilator-Induced Lung Injury.

OBJECTIVES: Ventilator-induced lung injury (VILI) is a major contributor to morbidity and mortality in critically ill patients. Mechanical damage to the lungs is potentially aggravated by the activation of the renin-angiotensin system (RAS). This article describes RAS activation profiles in VILI and discusses the effects of angiotensin (Ang) 1-7 supplementation or angiotensin-converting enzyme (ACE) inhibition with captopril as protective strategies. DESIGN: Animal study. SETTING: University research laboratory. SUBJECTS: C57BL/6 mice. INTERVENTIONS: Anesthetized mice ( n = 12-18 per group) were mechanically ventilated with low tidal volume (LV T , 6 mL/kg), high tidal volume (HV T , 15 mL/kg), or very high tidal volume (VHV T , 30 mL/kg) for 4 hours, or killed after 3 minutes (sham). Additional VHV T groups received infusions of 60 µg/kg/hr Ang 1-7 or a single dose of 100 mg/kg captopril. MEASUREMENTS AND MAIN RESULTS: VILI was characterized by increased bronchoalveolar lavage fluid levels of interleukin (IL)-6, keratinocyte-derived cytokine, and macrophage inflammatory protein-2 (MIP2). The Ang metabolites in plasma measured with liquid chromatography tandem mass spectrometry showed a strong activation of the classical (Ang I, Ang II) and alternative RAS (Ang 1-7, Ang 1-5), with highest concentrations found in the HV T group. Although the lung-tissue ACE messenger RNA expression was unchanged, its protein expression showed a dose-dependent increase under mechanical ventilation. The ACE2 messenger RNA expression decreased in all ventilated groups, whereas ACE2 protein levels remained unchanged. Both captopril and Ang 1-7 led to markedly increased Ang 1-7 plasma levels, decreased Ang II levels, and ACE activity (Ang II/Ang I ratio), and effectively prevented VILI. CONCLUSIONS: VILI is accompanied by a strong activation of the RAS. Based on circulating Ang metabolite levels and tissue expression of RAS enzymes, classical ACE-dependent and alternative RAS cascades were activated in the HV T group, whereas classical RAS activation prevailed with VHV T ventilation. Ang 1-7 or captopril protected from VILI primarily by modifying the systemic RAS profile.

Captopril alleviates oxidative damage in diabetic retinopathy.

AIMS: To primarily explore the mechanism of captopril in oxidative stress and investigate the link between captopril alleviated oxidative damage and diabetic retinopathy (DR). MAIN METHODS: Human retinal microvascular endothelial cells (HRMECs) were used for in vitro experiments and cultured in a 5.5 mM or 30 mM glucose medium. Sprague-Dawley rats were used for in vivo experiments, and parts of the rats were established for diabetic groups by injected streptozotocin (n = 10, each group). Both experiments had a captopril-treated group. The levels of total cholesterol (TC), reactive oxygen species (ROS), nitric oxide (NO), and human 3-nitrotyrosine (3-NT) were detected in assay kits and ELISA. Western blotting was used to detect the expression of steroid regulatory element binding protein 2 (SREBP2), inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF), and endothelial nitric oxide synthase (eNOS). Hematoxylin-eosin staining and Evans blue were used to describe retinal histopathology. KEY FINDINGS: The levels of TC, ROS, NO, and 3-NT were increased in the higher glucose groups compared with the normal controls during in vivo and in vitro experiments. Western blotting showed a higher level of SREBP2, iNOS, and VEGF and a lower eNOS level in the higher glucose groups. These results were reversed by captopril. Captopril relieved diabetic retinal vascular leakage. SIGNIFICANCE: Our study suggested that captopril alleviates oxidative damage in DR due to creating lower peroxynitrite by decreasing ROS and NO, which may provide a visible direction for DR research.

Hydrogen sulfide-dependent microvascular vasodilation is improved following chronic sulfhydryl-donating antihypertensive pharmacotherapy in adults with hypertension.

Hypertension is characterized by systemic microvascular endothelial dysfunction, in part due to a functional absence of hydrogen sulfide (H2S)-mediated endothelium-dependent dilation. Treatment with a sulfhydryl-donating ACE inhibitor (SH-ACE inhibitor) improves endothelial function in preclinical models of hypertension. To date, no studies have directly assessed the effects of SH-ACE-inhibitor treatment on H2S-dependent vasodilation in humans with hypertension. We hypothesized that SH-ACE-inhibitor treatment would improve H2S-mediated endothelium-dependent vasodilation. Ten adults with hypertension [1 woman and 9 men; 56 ± 9 yr; systolic blood pressure (SBP): 141 ± 8.5 mmHg; diastolic blood pressure (DBP): 90.3 ± 6 mmHg] were treated (16 wk) with the SH-ACE-inhibitor captopril. Red blood cell flux (laser-Doppler flowmetry) was measured continuously during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (ACh; 10-10 to 10-1 M) alone (control) and in combination with an inhibitor of enzymatic H2S production [10-3 M aminooxyacetate (AOAA)] preintervention and postintervention. Cutaneous vascular conductance (CVC; flux/mmHg) was calculated and normalized to the site-specific maximal CVC (0.028 M sodium nitroprusside and local heat to 43°C). Area under the curve was calculated using the trapezoid method. The 16-wk SH-ACE-inhibitor treatment resulted in a reduction of blood pressure (systolic BP: 129 ± 10 mmHg; diastolic BP: 81 ± 9 mmHg, both P < 0.05). Preintervention, inhibition of H2S production had no effect on ACh-induced vasodilation (316 ± 40 control vs. 322 ± 35 AU AOAA; P = 0.82). Captopril treatment improved ACh-induced vasodilation (316 ± 40 pre vs. 399 ± 55 AU post; P = 0.04) and increased the H2S-dependent component of ACh-induced vasodilation (pre: -6.6 ± 65.1 vs. post: 90.2 ± 148.3 AU, P = 0.04). These data suggest that SH-ACE-inhibitor antihypertensive treatment improves cutaneous microvascular endothelium-dependent vasodilation in adults with hypertension, in part via H2S-dependent mechanisms.NEW & NOTEWORTHY This is the first study to prospectively assess the effects of sulfhydryl antihypertensive treatment on microvascular endothelial function in adults with hypertension. Our data suggest that 16 wk of SH-ACE-inhibitor antihypertensive treatment improves cutaneous microvascular endothelium-dependent vasodilation in middle-aged adults with hypertension, in part via H2S-dependent mechanisms.

Structure-guided optimization of D-captopril for discovery of potent NDM-1 inhibitors.

ß-lactam antibiotics have long been the mainstay for the treatment of bacterial infections. New Delhi metallo-ß-lactamase 1 (NDM-1) is able to hydrolyze nearly all ß-lactam antibiotics and even clinically used serine-ß-lactamase inhibitors. The wide and rapid spreading of NDM-1 gene among pathogenic bacteria has attracted extensive attention, therefore high potency NDM-1 inhibitors are urgently needed. Here we report a series of structure-guided design of D-captopril derivatives that can inhibit the activity of NDM-1 in vitro and at cellular levels. Structural comparison indicates the mechanisms of inhibition enhancement and provides insights for further inhibitor optimization.

Whey-Derived Peptides Interactions with ACE by Molecular Docking as a Potential Predictive Tool of Natural ACE Inhibitors.

Several milk/whey derived peptides possess high in vitro angiotensin I-converting enzyme (ACE) inhibitory activity. However, in some cases, poor correlation between the in vitro ACE inhibitory activity and the in vivo antihypertensive activity has been observed. The aim of this study is to gain insight into the structure-activity relationship of peptide sequences present in whey/milk protein hydrolysates with high ACE inhibitory activity, which could lead to a better understanding and prediction of their in vivo antihypertensive activity. The potential interactions between peptides produced from whey proteins, previously reported as high ACE inhibitors such as IPP, LIVTQ, IIAE, LVYPFP, and human ACE were assessed using a molecular docking approach. The results show that peptides IIAE, LIVTQ, and LVYPFP formed strong H bonds with the amino acids Gln 259, His 331, and Thr 358 in the active site of the human ACE. Interestingly, the same residues were found to form strong hydrogen bonds with the ACE inhibitory drug Sampatrilat. Furthermore, peptides IIAE and LVYPFP interacted with the amino acid residues Gln 259 and His 331, respectively, also in common with other ACE-inhibitory drugs such as Captopril, Lisinopril and Elanapril. Additionally, IIAE interacted with the amino acid residue Asp 140 in common with Lisinopril, and LIVTQ interacted with Ala 332 in common with both Lisinopril and Elanapril. The peptides produced naturally from whey by enzymatic hydrolysis interacted with residues of the human ACE in common with potent ACE-inhibitory drugs which suggests that these natural peptides may be potent ACE inhibitors.

Transforming Non-Selective Angiotensin-Converting Enzyme Inhibitors in C- and N-domain Selective Inhibitors by Using Computational Tools.

The two-domain dipeptidylcarboxypeptidase Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in blood pressure regulation via the reninangiotensin and kallikrein-kinin systems by converting angiotensin I to the potent vasoconstrictor angiotensin II, and by cleaving a number of other substrates including the vasodilator bradykinin and the anti-inflammatory peptide N-acetyl-SDKP. Therefore, the design of ACE inhibitors is within the priorities of modern medical sciences for treating hypertension, heart failures, myocardial infarction, and other related diseases. Despite the success of ACE inhibitors for the treatment of hypertension and congestive heart failure, they have some adverse effects, which could be attenuated by selective domain inhibition. Crystal structures of both ACE domains (nACE and cACE) reported over the last decades could facilitate the rational drug design of selective inhibitors. In this review, we refer to the history of the discovery of ACE inhibitors, which has been strongly related to the development of molecular modeling methods. We stated that the design of novel selective ACE inhibitors is a challenge for current researchers which requires a thorough understanding of the structure of both ACE domains and the help of molecular modeling methodologies. Finally, we performed a theoretical design of potential selective derivatives of trandolaprilat, a drug approved to treat critical conditions of hypertension, to illustrate how to use molecular modeling methods such as de novo design, docking, Molecular Dynamics (MD) simulations, and free energy calculations for creating novel potential drugs with specific interactions inside nACE and cACE binding sites.

A Multi-Biochemical and In Silico Study on Anti-Enzymatic Actions of Pyroglutamic Acid against PDE-5, ACE, and Urease Using Various Analytical Techniques: Unexplored Pharmacological Properties and Cytotoxicity Evaluation.

In the current study, pyroglutamic acid (pGlu), a natural amino acid derivative, has efficiently inhibited the catalytic activities of three important enzymes, namely: Human recombinant phosphodiesterase-5A1 (PDE5A1), human angiotensin-converting enzyme (ACE), and urease. These enzymes were reported to be associated with several important clinical conditions in humans. Radioactivity-based assay, spectrophotometric-based assay, and an Electrospray Ionization-Mass Spectrometry-based method were employed to ascertain the inhibitory actions of pGlu against PDE5A1, ACE, and urease, respectively. The results unveiled that pGlu potently suppressed the activity of PDE5A1 (half-maximal inhibitory concentration; IC50 = 5.23 µM) compared with that of standard drug sildenafil citrate (IC50 = 7.14 µM). Moreover, pGlu at a concentration of 20 µg/mL was found to efficiently inhibit human ACE with 98.2% inhibition compared with that of standard captopril (99.6%; 20 µg/mL). The urease-catalyzed reaction was also remarkably inactivated by pGlu and standard acetohydroxamic acid with IC50 values of 1.8 and 3.9 µM, respectively. Remarkably, the outcome of in vitro cytotoxicity assay did not reveal any significant cytotoxic properties of pGlu against human cervical carcinoma cells and normal human fetal lung fibroblast cells. In addition to in vitro assays, molecular docking analyses were performed to corroborate the outcomes of in vitro results with predicted structure-activity relationships. In conclusion, pGlu could be presented as a natural and multifunctional agent with promising applications in the treatment of some ailments connected with the above-mentioned anti-enzymatic properties.

Renin-angiotensin system activation and imbalance of matrix metalloproteinase-9/tissue inhibitor of matrix metalloproteinase-1 in cold-induced stroke.

AIMS: In the present study, we investigated the roles of renin-angiotensin system (RAS) activation and imbalance of matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in cold-induced stroke during chronic hypertension, as well as the protective effects of captopril and recombinant human TIMP-1 (rhTIMP-1). MAIN METHODS: Rats were randomly assigned to sham; 2-kidney, 2-clip (2K-2C); 2K-2C + captopril, and 2K-2C + rhTIMP-1 groups. After blood pressure values had stabilized, each group was randomly divided into an acute cold exposure (ACE) group (12-h light at 22 °C/12-h dark at 4 °C) and a non-acute cold exposure (NACE) group (12-h light/12-h dark at 22 °C), each of which underwent three cycles of exposure. Captopril treatment was administered via gavage (50 mg/kg/d), while rhTIMP-1 treatment was administered via the tail vein (60 µg/kg/36 h). KEY FINDINGS: In the 2K-2C group, angiotensin II (AngII) and MMP-9 levels increased in both the plasma and cortex, while no such changes in TIMP-1 expression were observed. Cold exposure further upregulated AngII and MMP-9 levels and increased stroke incidence. Captopril and rhTIMP-1 treatment inhibited MMP-9 expression and activation and decreased stroke incidence in response to cold exposure. SIGNIFICANCE: The present study is the first to demonstrate that cold exposure exacerbates imbalance between MMP-9 and TIMP-1 by activating the RAS, which may be critical in the initiation of stroke during chronic hypertension. In addition, our results suggest that captopril and rhTIMP-1 exert protective effects against cold-induced stroke by ameliorating MMP-9/TIMP-1 imbalance.

Potential Angiotensin Converting Enzyme Inhibitors from Moringa oleifera.

BACKGROUND: Hypertension is the chronic medical condition and it affected billions of people worldwide. Natural medicines are the main alternatives to treatment for a majority of people suffering from hypertension. Niazicin-A, Niazimin-A, and Niaziminin-B compounds from Moringa oleifera ethanolic leave extract were reported to have potent antihypertensive activity. OBJECTIVE: These compounds were targeted with Angiotensin-converting enzyme [ACE] which is one of the main regulatory enzymes of the renin-angiotensin system. METHODS: Protein-ligand docking of these compounds with [ACE] [both domain N and C] was conceded out through Autodock vina and visualization was done by chimera. Pharmacokinetics study of these compounds was predicted by ADME-Toxicity Prediction. RESULTS: Niazicin-A, Niazimin-A, and Niaziminin-B showed high binding affinity with ACE and partially blocked the active sites of the enzyme. Niazicin-A, Niazimin-A and Niaziminin-B showed the estimated free binding energy of -7.6kcal/mol kcal/mol, -8.8kcal/mol and -8.0kcal/mol respectively with C-domain of ACE and -7.9kcal/mol, -8.5kcal/mol and -7.7kcal/mol respectively with N-domain of ACE. The compounds showed better binding energy with angiotensinconverting enzyme in comparison to Captopril -5.5kcal/mol and -5.6kcal/mol and Enalapril [standard] -8.4kcal/mol and -7.5kcal/mol with C and N domain, respectively. CONCLUSION: Computationally, the selected bioactive molecules have shown better binding energy to known standard drugs which have been already known for inhibition of ACE and can further act as a pharmacophore for in vitro and in vivo studies in the development of alternative medicine.

Application of Pickering Emulsion with Cyclodextrin as an Emulsifier to a Transdermal Drug Delivery Vehicle.

The emulsion prepared with ß-cyclodextrin as an emulsifier (ßCDE) is considered to be a Pickering emulsion. We examined the characteristics of ßCDEs using captopril (CP) as a model drug, and studied the in vitro skin permeation of CP from ßCDEs through hairless mouse skin. The stability of ßCDE was increased with increasing ßCD concentration and conversely decreased with increasing CP concentration. The yield stress value from the rheological measurement results was suggested to be one of the factors determining the stability of the ßCDE, and ßCDEs with higher yield stress values were more stable. We found that the skin permeability of CP could be improved by using ßCDE with isopropyl myristate as the oil phase and that the flux of CP depended on the free CP concentration in the water phase of ßCDE.

A novel S-nitrosocaptopril monohydrate for pulmonary arterial hypertension: H2O and -SNO intermolecular stabilization chemistry.

S-nitrosocaptopril (CapNO) possesses dual capacities of both Captopril and an NO donor with enhanced efficacy and reduced side effects. CapNO crystals are difficult to make due to its unstable S-NO bond. Here, we report a novel stable S-nitrosocaptopril monohydrate (CapNO·H2O) that is stabilized by intermolecular five-membered structure, where one H of H2O forms a hydrogen bond with O- of the stable resonance zwitterion Cap-S+=N-O-, and the O in H2O forms the dipole-dipole interaction with S+ through two unpaired electrons. With the chelation and common ion effect, we synthesized and characterized CapNO·H2O that is stable at 4 °C for 180 days and thereafter without significant degradation. Compared to Captopril, CapNO showed direct vasorelaxation and beneficial effect on PAH rats, and could be self-assembled in rat stomach when Captopril and NaNO2 were given separately. This novel CapNO·H2O with low entropy paves an avenue for its clinical trials and commercialization.

Bioconjugation of Captopril-Light Subunit of Agaricus bisporus Mushroom Tyrosinase: Characterization and Potential Use as a Drug Carrier for Oral Delivery.

We show that a lectin like protein from the mushroom Agaricus bisporus (LSMT) is capable to permeate the epithelial monolayer barrier of the intestine ex vivo. The protein is not toxic or immunogenic upon prolonged administration and elevated dose in mice. Thus, it could be a candidate as a drug carrier for oral administration. However, its permeability should be tested after the protein has been modified, mimicking the condition in which it is used as a drug carrier. The protein was conjugated to captopril, the selected model of a Biopharmaceutical Classification System (BCS) class III drug, with high solubility but poor permeability. The drug was conjugated to LSMT that had been modified with 4-succinimidyloxycarbonyl-alpha-methyl-2-pyridyldithiotoluene (SMPT) as a linker. The success of LSMT modification was confirmed with TLC and MS; the latter also indicated the amount of captopril molecule linked. The modified LSMT could permeate through the intestinal monolayer barrier, and thus could be absorbed in the intestine after modification. The modified protein appears to remain stable after incubation in simulated gastrointestinal fluids. This pioneering work provides an essential basis for further development of the protein as a drug carrier for oral administration.

Probing the interaction of l-captopril with metallo-ß-lactamase CcrA by fluorescence spectra and molecular dynamic simulation.

Both the molecular recognition and interaction of metallo-ß-lactamase CcrA with l-captopril were studied by the combined use of fluorescence spectra and molecular dynamic simulation. The results showed that the binding constant was 8.89 × 104  L mol-1 at 296 K. Both Zn1 and Zn2 displayed tetrahedral coordination geometries in the CcrA-Lcap complex, the S atom in l-captopril displaced the nucleophilic hydroxide in apo CcrA and occupied the fourth coordination site for each ion, resulting in a competitively inhibited CcrA enzyme. Strong electrostatic interaction between the two zinc ions in CcrA and negatively charged l-captopril provided the main driving force for the binding affinity. Through a partly structural transformation from ß-sheet to random coil, loop 1 (residues 24-34) completely opened the binding pocket of CcrA to allow an induced fit of the newly introduced ligand. This study may provide some valuable information for designing and developing a more tightly binding inhibitor to resist superbugs.

Formulation, Characterization, and Optimization of Captopril Fast-Dissolving Oral Films.

This work aimed to using optimization study to formulate a patient-friendly captopril fast-dissolving oral film with satisfactory disintegration time. Films were made with pullulan and hydroxypropyl methyl cellulose (HPMC) by using the solvent-casting method. Cellulose nanofiber (CNF) was used as a compatibilizer and glycerine was used as a plasticizer. In order to find an optimum formulation, a response surface methodology and a central composite design were employed. The concentration percentages of pullulan and glycerine were considered to be the design factors. Disintegration time, tensile strength, percent elongation at break, and folding endurance were considered to be the responses. The results showed that CNF improved the compatibility and tensile strength of the pullulan and HPMC blend. Also, the rigid nature of CNF reduced the film elongation but the addition of glycerine improved its flexibility. All formulations showed an acceptable uniformity content and dissolution rate. Complete dissolution for all formulations occurred within 2 min. Films with 26% pullulan, 74% HPMC, 1% CNF, and 5% glycerine were reported to be optimum formulations for captopril fast-dissolving oral films, with 95% confidence levels. The in vivo comparison of optimized formulation with a conventional captopril sublingual tablet exhibited significant increase in AUC (~ 62%) and Cmax (~ 52%) and a major decrease in Tmax (~ 33%). The overall results showed that the captopril FDF is a promising candidate for enhanced in vivo orotransmucosal absorption.