Aminoguanidine Derivatives Research Articles

Synthesis and biological evaluation of novel aminoguanidine derivatives as potential antibacterial agents

In an effort to identify novel antibacterial agents, we presented two series of aminoguanidine derivatives that were designed by incorporating 1,2,4-triazol moieties. All compounds exhibited strong in vitro antibacterial activity against a variety of testing strains. Compound 5f was identified as a potent antibacterial agent with a minimum inhibitory concentration (MIC) of 2–8 µg/mL against S. aureus, E. coli, S. epidermidis, B. subtilis, C. albicans, multi-drug resistant Staphylococcus aureus and multi-drug resistant Escherichia coli and low toxicity (Hela > 100 µM). Membrane permeability and transmission electron microscopy (TEM) image studies demonstrated that compound 5f permeabilized bacterial membranes, resulting in irregular cell morphology and the rapid death of bacteria. The results of the present study suggested that aminoguanidine derivatives with 1,2,4-triazol moieties were the intriguing scaffolds for the development of bactericidal agents.

Synthesis, anti-oomycete and anti-fungal activities of aminoguanidine derivatives of paeonol sulfonate

In order to explore novel natural product-based anti-oomycete and anti-fungal agents, fifteen aminoguanidine derivatives of paeonol sulfonate (5a-o) were designed and synthesized , and their structures were confirmed by 1H NMR, 13C NMR, HRMS, and melting point. The stereochemical configurations of compounds 5i and 5j have been confirmed by single-crystal X-ray diffraction. In addition, the anti-oomycete and anti-fungal activities of these target compounds against two serious agricultural diseases, Phytophthora capsici and Fusarium graminearum were evaluated by mycelial growth rate method. Among all tested compounds, 1) Four compounds 5e, 5f, 5g, and 5o exhibited promising anti-oomycete against P. capsici, with median effective concentration (EC50) values of 4.27, 9.20, 4.77, and 6.94 mg/L, respectively. 2) Compound 5 g displayed promising anti-fungal against F. graminearum, with an EC50 value of 17.75 mg/L. The results showed that the introduction of aminoguanidine active groups in the carbonyl position of paeonol sulfonate could enhance its activity against plant pathogens.

A novel bakuchiol aminoguanidine derivative induces apoptosis in human triple-negative breast cancer cells.

To synthesize new bakuchiol aminoguanidine derivatives and test their effect on viability and apoptosis of human triple-negative breast cancer (TNBC) cells. Two bakuchiol derivatives 1 and 2 were obtained by formylation and Shiff base reaction of bakuchol. The structures of derivatives 1 and 2 were identified by 1H-NMR, 13C-NMR, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analysis. Human TNBC MDA-MB-231 cells were treated with bakuchiol and its derivatives and cell viability was measured by MTT assay. Apoptosis was detected by fluorescence microscopy and flow cytometry with Annexin V-FITC/PI staining. The expressions of apoptosis-related proteins were analyzed with Western blotting. The JC-1 and reactive oxygen species (ROS) assay kits were used to determine the effect of new bakuchiol derivatives on mitochondrial function. Based on spectroscopic analysis, a new bakuchiol schiff base derivative was elucidated as 2-{(E)-5-[(S, E)-3, 7-dimethyl-3-vinylocta-1, 6-dien-1-yl]-2-hydroxylbenzylidene} hydrazine-1-carboximidamide (derivative 2). Bakuchiol and its derivatives 1 and 2 all showed cytotoxic activity against the MDA-MB-231 cells. Derivative 2 exhibited the most potent cytotoxic activity to MDA-MB-231 cell with IC50 of (13.11±1.09), (6.91±1.78), and (2.23±1.32) μmol/L after 24, 48, and 72 h. It had low toxicity to normal mouse liver (AML-12) cells with IC50 of (31.23±1.58) μmol/L at 72 h. Fluorescence microscopy and flow cytometry demonstrated apoptosis in breast cancer cells after treating with derivative 2 in a concentration dependent manner. Western blotting showed that after derivative 2 treatment, the expression of apoptosis-related proteins cytochrome C, cleaving caspase-3 and Bax/Bcl-2 radio in MDA-MB-231 cells increased; in addition, apoptosis was associated with the decreased mitochondrial membrane potential and increased reactive oxygen species accumulation. The novel bakuchiol aminoguanidine derivative (derivative 2) is capable of inducing apoptosis in MDA-MB-231 cells, but has low toxicity to normal liver cells, suggesting that it may be used as a lead compound for an anti-TNBC agent.

Reactions of 2-acetylpyridine aminoguanidine with Cu(II) under different reaction conditions

Aminoguanidine derivatives are the focus of research because of their various biological activities, such as antiviral, antibacterial, analgesic, antioxidant and anticancer. Their complexes with different metals are also examined and many of them show significant biological activity, too. Besides, some of the complexes show good photoluminescent properties and are used for the preparation of photoelectronic devices. Therefore, the synthesis, physicochemical, structural and thermal characterization of the complexes of 2-acetylpyridine- aminoguanidine (L) with copper (II) are described here. Under different reaction conditions, Cu(II) with L gives three complexes of different compositions. By varying the strength of basicity of the deprotonating agent used, it was proven here that the Schiff base given here could be coordinated in neutral or monoanionic form. In the presence of pyridine, a coordination polymer is obtained, while in the presence of ammonia/lithium acetate two different monomeric complexes were crystallised. Their physicochemical and thermal properties, as well as molecular and crystal structure, are determined.

Synthesis, Characterization, Biological Activity and Molecular Modeling Studies of Novel Aminoguanidine Derivatives

AbstractIn recent years, various compounds including the aminoguanidine scaffold have been reported to exhibit diverse biological activities. In the current study, 16 compounds that include guanylhydrazone (aminoguanidine) moiety (3 a–3 p) were synthesized and characterized through the spectrum data, including 1H‐NMR, 13C‐NMR, and FT‐IR. Furthermore, the proposed structure of 3 a was resolved by single‐crystal X‐ray diffractometer. The prepared compounds were then tested for their different in vitro biological activities including antitumor activities against several types of cancer cell lines (A549, MCF‐7, and U87‐MG). Results showed that among the studied compounds especially 3 i, 3 n, and 3 p showed promising antiproliferative effect and they may be considered as good candidates for further in vitro and/or in vivo animal model studies. All the 16 derivatives synthesized in this study were also screened for their antimicrobial, antioxidant activity and DNA cleavage properties. Furthermore, multidimensional molecular modeling approaches were conducted for better understanding of their biological activities in atomic level.

A Review of the Biological Activity of Amidrazone Derivatives.

Amidrazones are widely used in chemical synthesis, industry and agriculture. We compiled some of the most important findings on the biological activities of amidrazones described in the years 2010–2022. The data were obtained using the ScienceDirect, Reaxys and Google Scholar search engines with keywords (amidrazone, carbohydrazonamide, carboximidohydrazide, aminoguanidine) and structure strategies. Compounds with significant biological activities were included in the review. The described structures derived from amidrazones include: amidrazone derivatives; aminoguanidine derivatives; complexes obtained using amidrazones as ligands; and some cyclic compounds obtained from amidrazones and/or containing an amidrazone moiety in their structures. This review includes chapters based on compound activities, including: tuberculostatic, antibacterial, antifungal, antiparasitic, antiviral, anti-inflammatory, cytoprotective, and antitumor compounds, as well as furin and acetylocholinesterase inhibitors. Detailed information on the compounds tested in vivo, along the mechanisms of action and toxicity of the selected amidrazone derivatives, are described. We describe examples of compounds that have a chance of becoming drugs due to promising preclinical or clinical research, as well as old drugs with new therapeutic targets (repositioning) which have the potential to be used in the treatment of other diseases. The described examples prove that amidrazone derivatives are a potential source of new therapeutic substances and deserve further research.

The effect of an aminoguanidine derivative on adjuvant arthritis in rats

Aim. To study anti-inflammatory, analgesic, and possible ulcerogenic effects of a novel aminoguanidine derivative in adjuvant arthritis (a model of rheumatoid arthritis) in rats.Materials and methods. The experiments were carried out on 42 outbred male Sprague Dawley rats. After modeling arthritis (starting from day 7 after the administration of complete Freund’s adjuvant), intramuscular injections of the aminoguanidine derivative (code LIS-M) at a dose of 2.5, 5, and 10 mg / kg or the reference drug diclofenac at a dose of 4 mg / kg were performed once a day for 22 days. The volume of the inflamed limb was measured twice a week, pain threshold was measured every week. After finishing the administration of the compounds, the levels of interleukin (IL) 1, IL-6, and tumor necrosis factor-α (TNFα) were measured in rat plasma, the ankle joint was histologically studied, and the gastric mucosa was studied to detect damage, ulcers, and scarring.Results. The aminoguanidine derivative, an inhibitor of inducible nitric oxide synthase, was more effective at the dose of 10 mg / kg than diclofenac at the dose of 4 mg / kg. It had anti-inflammatory and analgesic effects in the joint affected by complete Freund’s adjuvant, promoted restoration of the histologic structure in the synovial membrane and articular cartilage, and reduced the plasma concentration of IL-1, IL-6, and TNFα by 1.4–1.5 times. The LIS-M compound did not damage the gastric mucosa in rats with adjuvant arthritis.Conclusion. The aminoguanidine derivative LIS-M exerts potent anti-inflammatory and analgesic effects in adjuvant arthritis in rats (a model of rheumatoid arthritis). LIS-M has no ulcerogenic effect on the gastric mucosa in rats.

Synthesis, characterization and antimicrobial effect of Cu(ii) and Zn(ii) compounds derived from 1,2,4-triazoles

Compounds of Cu(II) and Zn(II) with 3-R-1H-1,2,4-triazole-5-amine {R = methyl (mta), phenyl (pta)} were prepared and characterized by infrared spectroscopy (IR), multinuclear NMR (1H, 13C), electronic spectroscopy (UV-VIS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), microanalyses and melting point. Dimeric, monomeric, and polymeric materials were synthesized in this work. The Zn(II)-1,2,4-triazole derivatives have the metal ion at the center of two geometric arrangements, being a tetrahedron for the complex-7 and 9, and an octahedron for the complex-8. The only polymeric material, complex-7, was characterized by the DSC analytical data. The Decomposition reaction of complex-8 in chloroform produced the complex-9, a aminoguanidine derivative, and the Zn(II)-benzoate compound. The IR and UV-VIS of Cu(II)-mta derivatives revealed two possible geometric patterns for the metallic ion; a distorted bipyramidal trigonal geometry for compounds 10 and 11 in solution, and in the solid state, the same geometry for complex-10, but for complex-11, the IR data suggest a distorted octahedral geometry. The biological assay of the 1,2,4-triazole compounds and their metal derivatives against Gram-positive and Gram-negative bacteria shown the compounds of Zn(II) as the only active materials with values of MIC within the range of 133.5 µM (83.3 µg / mL) to 360.7 µM (166.6 µg / mL).

Противовоспалительное и анальгетическое действие ингибитора индуцируемой синтазы оксида азота в эксперименте

Introduction. Nitric oxide plays a key role in the development of inflammation. In this regard, it is promising to create a drug that reduces the production of nitric oxide in the focus of inflammation. Aim. To study experimentally the anti-inflammatory and analgesic effects of an inducible nitric oxide synthase inhibitor of an aminoguanidine derivative (LIS-M). Materials and methods. The compound LIS-M in 1% aqueous solution of polyvinylpyrrolidone was administered intramuscularly at doses of 5, 10 and 20 mg/kg to 150 male Sprague Dawley rats and 50 male CD-1 mice with experimental models of inflammation and pain. The animals of the comparison group received diclofenac at a dose of 10 mg/kg, the animals of the control group received 1% aqueous solution of polyvinylpyrrolidone in an equivalent volume. The effect of the LIS-M compound on the course of experimental pathology and its analgesic potential ulcerogenic effect were evaluated. Results. In male Sprague Dawley rats, the LIS-M compound reduces acute exudative inflammation caused by injection of carrageenan, histamine or serotonin in plantar aponeurosis, inhibits the proliferation of granulation tissue and exudation around a cotton swab implanted under the skin, does not have an ulcerogenic effect. In male CD-1 mice, it weakens the pain reaction and increases the time before it occurs. Conclusion. The LIS-M compound at doses ranging from of 5 to 20 mg/kg has a pronounced antiexudative, antiproliferative and analgesic effect, not inferior to the action of diclofenac at a dose of 10 mg/kg, and does not have an ulcerogenic effect.

Synthesis, Antimicrobial Activity, and Molecular Docking Studies of Aminoguanidine Derivatives Containing an Acylhydrazone Moiety.

A series of aminoguanidine derivatives containing an acylhydrazone moiety was designed based on combination principles to find new antibacterial agents with wide spectra and high activities. The synthesized compounds were characterized by spectral methods and screened for their antibacterial activity. The results showed that several compounds provided great antimicrobial activities against Gram-positive bacteria (including the multidrug-resistant clinical isolates). Especially, this series of compounds presented high potency against Staphylococcus aureus, among which the derivative 3f was the most promising one with a MIC value of 4 μg/mL. Compound 3d, with a tertiary butyl group, was found to have the broad spectrum inhibitory capacity, which is effective to eight strains and showed the most potent inhibitory activity against B. subtilis CMCC 63501 with a MIC value of 4 μg/mL. What’s more, compound 3d also presented high activities against four multidrug-resistant strains, which were comparable or potent to oxacillin and penicillin. Molecular docking studies revealed that H-bond interaction with amino acid residue THR81 and alkyl hydrophobic interaction with residue ALA246 of FabH were crucial for their binding force and in-vitro antimicrobial activities.

Indole-3-guanylhydrazone hydrochloride mitigates long-term cognitive impairment in a neonatal sepsis model with involvement of MAPK and NFκB pathways

BackgroundNeonatal sepsis is defined as a systemic inflammatory response caused by a suspected or proven infection, occurring in the first month of life, and remains one of the main causes of morbidity and mortality in newborn and preterm infants. Frequently, survivors of neonatal sepsis have serious long-term cognitive impairment and adverse neurologic outcomes. There is currently no specific drug treatment for sepsis. Indole-3-guanylhydrazone hydrochloride (LQM01) is an aminoguanidine derivative that has been described as an anti-inflammatory, antihypertensive and antioxidant with potential applicability in inflammatory diseases. MethodsWe used a LPS-challenged neonatal sepsis rodent model to investigate the effect of LQM01 on cognitive impairment and anxiety-like behavior in sepsis mice survivors, and examined the possible molecular mechanisms involved. ResultsIt was found that LQM01 exposure during the neonatal period reduces anxiety-like behavior and cognitive impairment caused by lipopolysaccharides (LPS) in adult life. Additionally, treatment with LQM01 decreased pro-inflammatory cytokine levels and reduced NFκB, COX-2, MAPK and microglia activation in hippocampus of neonatal mice. Furthermore, LQM01 was also able to prevent oxidative damage in hippocampus of neonatal mice and preserve brain barrier integrity. ConclusionsLQM01 attenuated inflammatory reactions in an LPS-challenged neonatal sepsis mice model through the MAPK and NFκB signaling pathways and microglia activation suppression. All these findings are associated with mitigated cognitive impairment in 70 days-old LQM01 treated-mice. General significanceWe revealed the effect of LQM01 as an anti-septic agent, and the role of crucial molecular pathways in mitigating the potential damage caused by neonatal sepsis.

Synthesis and Antimicrobial Activity Evaluation of Aminoguanidine Derivatives Containing a Biphenyl Moiety

Synthesis and Antimicrobial Activity Evaluation of Aminoguanidine Derivatives Containing a Biphenyl Moiety

Application of bioisosterism in design of the semicarbazone derivatives as cruzain inhibitors: a theoretical and experimental study

A series of semicarbazone, thiosemicarbazone, and aminoguanidine derivatives were synthesized and tested as antitrypanosomal agents. The theoretical NMR of the compounds was calculated using molecular modeling techniques (density functional theory (DFT) calculations) and confirmed the formation of the compounds. The ability to inhibit cruzain and Trypanosoma cruzi epimastigote replication was evaluated. Cruzain inhibition ranged between 70 and 75% (100 μM), and IC50 values observed in epimastigote forms of T. cruzi ranged from 20 to 140 μM. Furthermore, the compounds did not present cytotoxicity at concentrations up to 50 and 250 μM in MTT tests. Molecular modeling studies were conducted using DFT method (B3LYP functional and the basis set 6-311G(d,p)) to understand the activity of the compounds, corroborating the observed cruzain inhibitory activity. In docking studies, the obtained analogs showed good complementarity with cruzain active site. In addition, docking results are in accordance with the susceptibility of these analogs to nucleophilic attack of the catalytic Cys25. Taken together, this study shows that this class of compounds can be used as a prototype in the identification of new antichagasic drugs.

The chemistry of aminoguanidine derivatives – preparation, crystal structure, thermal properties, and molecular docking studies of aminoguanidinium salts of several carboxylic acids

The reaction of aminoguanidine bicarbonate (Amg) with oxamic, oxalic, malonic and sulfoacetic acids yielded (AmgH)H2NOC–COO (1), OOC–CONHNHC(NH2)NH2 (2) (AmgH)HOOC–CH2–COO (3) and O3S–CH2–CONHNHC(NH2)NH2 (4), respectively. For the first time, we studied the salt-forming ability of aminoguanidine with several carboxylic acids, such as oxamic, oxalic, malonic and sulphoacetic acids. We also compared the structural and thermal properties of these salts. Oxamic and malonic acids form only mono-aminoguanidinium salts, whereas oxalic acid mainly forms di-aminoguanidinium oxalate. In addition, oxalic acid forms guanylhydrazido-oxalic acid which exists as zwitter ion. Unlike other acids, sulfoacetic acid readily forms only the zwitter ionic salts (2-guanylhydrazido-oxo-methanesulfonic acid) rather than the usual simple salt. This result may be a result of the highly acidic nature of the sulfonic group, which favors acid catalyzed condensation. More significantly, for the first time, the ability guanylhydrazido-oxalic acid (2) and 2-guanylhydrazido-oxo-methanesulfonic acid (4) to inhibit human butyrylcholinesterase (human BChE) receptor has been studied with a molecular docking approach. The binding of the compounds to human BChE was examined as it is crucial to understanding the biological significance of aminoguanidine derivatives. The compounds were identified and characterized by analytical, FT-IR spectroscopic and thermal studies. Furthermore, the structures of compounds 1, 2 and 4 were confirmed by single X-ray diffraction studies. Compounds 1 and 2 crystallized in a monoclinic crystal system with P21/c and Cc space groups, respectively, whereas compound 4 crystalized in an orthorhombic system with a Pbca space group. All the compounds (1–4) underwent endo- followed by exothermic decomposition in the temperature range from 130 to 600°C to yield gaseous products.

Pharmacophore modeling, virtual screening and 3D-QSAR studies of 5-tetrahydroquinolinylidine aminoguanidine derivatives as sodium hydrogen exchanger inhibitors

Sodium hydrogen exchanger (SHE) inhibitor is one of the most important targets in treatment of myocardial ischemia. In the course of our research into new types of non-acylguanidine, SHE inhibitory activities of 5-tetrahydroquinolinylidine aminoguanidine derivatives were used to build pharmacophore and 3D-QSAR models. Genetic Algorithm Similarity Program (GASP) was used to derive a 3D pharmacophore model which was used in effective alignment of data set. Eight molecules were selected on the basis of structure diversity to build 10 different pharmacophore models. Model 1 was considered as the best model as it has highest fitness score compared to other nine models. The obtained model contained two acceptor sites, two donor atoms and one hydrophobic region. Pharmacophore modeling was followed by substructure searching and virtual screening. The best CoMFA model, representing steric and electrostatic fields, obtained for 30 training set molecules was statistically significant with cross-validated coefficient (q2) of 0.673 and conventional coefficient (r2) of 0.988. In addition to steric and electrostatic fields observed in CoMFA, CoMSIA also represents hydrophobic, hydrogen bond donor and hydrogen bond acceptor fields. CoMSIA model was also significant with cross-validated coefficient (q2) and conventional coefficient (r2) of 0.636 and 0.986, respectively. Both models were validated by an external test set of eight compounds and gave satisfactory prediction (rpred2) of 0.772 and 0.701 for CoMFA and CoMSIA models, respectively. This pharmacophore based 3D-QSAR approach provides significant insights that can be used to design novel, potent and selective SHE inhibitors.

Resorcylidene Aminoguanidine (RAG) Improves Cardiac Mitochondrial Bioenergetics Impaired by Hyperglycaemia in a Model of Experimental Diabetes

Diabetes is associated with a mitochondrial dysfunction. Hyperglycaemia is also clearly recognized as the primary culprit in the pathogenesis of cardiac complications. In response to glycation and oxidative stress, cardiac mitochondria undergo cumulative alterations, often leading to heart deterioration. There is a continuous search for innovative treatment strategies for protecting the heart mitochondria from the destructive impact of diabetes. Aminoguanidine derivatives have been successfully used in animal model studies on the treatment of experimental diabetes, as well as the diabetes-driven dysfunctions of peripheral tissues and cells. Considerable attention has been paid particularly to β-resorcylidene aminoguanidine (RAG), often shown as the efficient anti-glycation and anti-oxidant agent in both animal studies and in vitro experiments. The aim of the present study was to test the hypothesis that RAG improves oxidative phosphorylation and electron transport capacity in mitochondria impaired by hyperglycaemia. Diabetes mellitus was induced in Wistar rats by a single intraperitoneal injection of streptozotocin (70 mg/kg body weight). Heart mitochondria were isolated from healthy rats and rats with streptozotocin-diabetes. Mitochondrial respiratory capacity was measured by high resolution respirometry with the OROBOROS Oxygraph-2k according to experimental protocol including respiratory substrates and inhibitors. The results revealed that RAG protects the heart against diabetes-associated injury by improving the mitochondrial bioenergetics, thus suggesting a possible novel pharmacological strategy for cardioprotection.

Antifungal agents. Part 5: Synthesis and antifungal activities of aminoguanidine derivatives of N-arylsulfonyl-3-acylindoles

In order to discover more promising antifungal agents, a series of aminoguanidine derivatives of N-arylsulfonyl-3-acylindoles (5a-r) were prepared and evaluated in vitro for their antifungal activities against seven phytopathogenic fungi. Especially compounds 5n and 5o exhibited more potent antifungal activities than or comparable to hymexazol, a commercially available agricultural fungicide at the concentration of 100 μg/mL. Preliminary structure-activity relationships study demonstrated that introduction of electron-donating substituents R(1) and R(2), and the proper length of substituent R(3) were usually very important for their antifungal activities.

A novel N-hydroxy-N′-aminoguanidine derivative inhibits ribonucleotide reductase activity: Effects in human HL-60 promyelocytic leukemia cells and synergism with arabinofuranosylcytosine (Ara-C)

Ribonucleotide reductase (RR; EC 1.17.4.1) is responsible for the de novo conversion of ribonucleoside diphosphates into deoxyribonucleoside diphosphates, which are essential for DNA replication. RR is upregulated in tumor cells and therefore considered to be an excellent target for cancer chemotherapy. ABNM-13 (N-hydroxy-2-(anthracene-2-yl-methylene)-hydrazinecarboximidamide), a novel N-hydroxy-N′-aminoguanidine has been designed to inhibit RR activity using 3D molecular space modeling techniques. In this study, we evaluated its effect on human HL-60 promyelocytic leukemia cells. ABNM-13 proved to be a potent inhibitor of RR which was displayed by significant alterations of deoxyribonucleoside triphosphate (dNTP) pool balance and a highly significant decrease of incorporation of radiolabeled cytidine into DNA of HL-60 cells. Diminished RR activity caused replication stress which was consistent with activation of Chk1 and Chk2, resulting in downregulation/degradation of Cdc25A. In contrast, Cdc25B was upregulated, leading to dephosphorylation and activation of Cdk1. The combined disregulation of Cdc25A and Cdc25B was the most likely cause for ABNM-13 induced S-phase arrest. Finally, we combined ABNM-13 with the first-line antileukemic agent arabinofuranosylcytosine (Ara-C) and found that ABNM-13 synergistically potentiated the antineoplastic effects of Ara-C. Due to these promising results, ABNM-13 deserves further preclinical and in vivo testing.

ChemInform Abstract: Synthesis and Bioactivity of Substituted Indan‐1‐ylidene Aminoguanidine Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis and bioactivity of substituted indan-1-ylideneaminoguanidine derivatives

In our efforts to discover more potent and lasting NHE1 inhibitors, we designed and synthesized a series of substituted indan-1-ylidene aminoguanidine derivatives ( 5). NHE1 inhibitory activity of twenty-one compounds 5 was evaluated in a rat platelet swelling assay. It is found that most of the tested compounds possess NHE1 inhibitory effects. 2-(5-methoxybenzimidazol-2-ylthio)-5-chloro-2,3-dihydroinden-1-ylidene aminoguanidine hydrobromide ( 5m) proved to be sixty-nine times more potent than cariporide. Furthermore, when tested in vivo, compound 5m also displayed superior cardioprotective effects against SD rat myocardial ischemic–reperfusion injury over those of cariporide.