N-acylhydrazone Derivatives Research Articles

Development of Novel N-Acylhydrazone Derivatives with High Anti-obesity Activity and Improved Safety by Exploring the Pharmaceutical Properties of Aldehyde Group.

The discovery of effective and safe antiobesity agents remains a challenging yet promising field. Our previous studies identified Bouchardatine derivatives as potential antiobesity agents. However, the 8a-aldehyde moiety rendered them unsuitable for drug development. In this study, we designed two series of novel derivatives to modify this structural feature. Through a structure-activity relationship study, we elucidated the role of the 8a-aldehyde group in toxicity induction. We identified compound 14d, featuring an 8a-N-acylhydrazone moiety, which exhibited significant lipid-lowering activity and reduced toxicity. Compound 14d shares a similar lipid-lowering mechanism with our lead compound 3, but demonstrates improved pharmacokinetic properties and safety profile. Both oral and injectable administration of 14d significantly reduced body weight gain and ameliorated metabolic syndrome in diet-induced obese mice. Our findings identify 14d as a promising antiobesity agent and highlight the potential of substituting the aldehyde group with an N-acylhydrazone to enhance drug-like properties.

Synthesis, characterization, and MAO inhibitory activities of three new drug-like N-acylhydrazone derivatives

In this study, three new N-acylhydrazone derivatives with the structural motif of N'-(substitutedbenzylidene)-3-(5-methyl-2-benzoxazolinon-3-yl)propanehydrazide (5a-c) are prepared and evaluated for their MAO inhibitory activities. The structures of the synthesized compounds are elucidated through spectral methods (IR, 1H-NMR, 13C-NMR), elemental analysis and single crystal X-ray crystallography. Detailed structural and Hirshfeld surface analyses of compounds (5a-c) have provided further insights into their molecular and crystal structures and also their intermolecular interactions. Complementing the spectral and structural analyses confirmed the E-configurations of the compounds in the solid state. The Hirshfeld surface analyses of the crystal structures have indicated that the most important contributions for the crystal packings are from H ... H, H … C/C … H and H … O/O … H (for 5a-c) and H … F/F … H (for 5b and c). In vitro tests are revealed their MAO inhibitory activities, surpassing reference compounds moclobemide and selegiline. Notably, synthesized N-acylhydrazone derivatives (5a-c) are exhibited superior MAO inhibitory activities, with a higher selectivity for MAOB over MAOA (SI >10). Molecular docking studies are provided insights into the binding modes of the compounds in the active site of the target enzyme. Theoretical ADME (Absorption, Distribution, Metabolism and Excretion), gastrointestinal absorption and blood-brain barrier permeation studies revealed that the compounds possess pharmacological attributes resembling those of typical drugs. This properties and MAO inhibitory activities of N-acyl hydrazone derivatives emphasize their potentials as promising candidates in the field of medicinal chemistry.

Selective inhibition of HDAC6 by N-acylhydrazone derivative reduces the proliferation and induces senescence in carcinoma hepatocellular cells

Hepatocellular carcinoma (HCC) is a significant contributor to cancer-related deaths globally. Systemic therapy is the only treatment option for HCC at an advanced stage, with limited therapeutic response. In this study, we evaluated the antitumor potential of four N-acylhydrazone (NAH) derivatives, namely LASSBio-1909, 1911, 1935, and 1936, on HCC cell lines. We have previously demonstrated that the aforementioned NAH derivatives selectively inhibit histone deacetylase 6 (HDAC6) in lung cancer cells, but their effects on HCC cells have not been explored. Thus, the present study aimed to evaluate the effects of NAH derivatives on the proliferative behavior of HCC cells. LASSBio-1911 was the most cytotoxic compound against HCC cells, however its effects were minimal on normal cells. Our results showed that LASSBio-1911 inhibited HDAC6 in HCC cells leading to cell cycle arrest and decreased cell proliferation. There was also an increase in the frequency of cells in mitosis onset, which was associated with disturbing mitotic spindle formation. These events were accompanied by elevated levels of CDKN1A mRNA, accumulation of CCNB1 protein, and sustained ERK1 phosphorylation. Furthermore, LASSBio-1911 induced DNA damage, resulting in senescence and/or apoptosis. Our findings indicate that selective inhibition of HDAC6 may provide an effective therapeutic strategy for the treatment of advanced HCC, including tumor subtypes with integrated viral genome. Further, in vivo studies are required to validate the antitumor effect of LASSBio-1911 on liver cancer.

Antiproliferative Activity of N-Acylhydrazone Derivative on Hepatocellular Carcinoma Cells Involves Transcriptional Regulation of Genes Required for G2/M Transition.

Liver cancer is the second leading cause of cancer-related death in males. It is estimated that approximately one million deaths will occur by 2030 due to hepatic cancer. Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer subtype and is commonly diagnosed at an advanced stage. The drug arsenal used in systemic therapy for HCC is very limited. Multikinase inhibitors sorafenib (Nexavar®) and lenvatinib (Lenvima®) have been used as first-line drugs with modest therapeutic effects. In this scenario, it is imperative to search for new therapeutic strategies for HCC. Herein, the antiproliferative activity of N-acylhydrazone derivatives was evaluated on HCC cells (HepG2 and Hep3B), which were chemically planned on the ALL-993 scaffold, a potent inhibitor of vascular endothelial growth factor 2 (VEGFR2). The substances efficiently reduced the viability of HCC cells, and the LASSBio-2052 derivative was the most effective. Further, we demonstrated that LASSBio-2052 treatment induced FOXM1 downregulation, which compromises the transcriptional activation of genes required for G2/M transition, such as AURKA and AURKB, PLK1, and CDK1. In addition, LASSBio-2052 significantly reduced CCNB1 and CCND1 expression in HCC cells. Our findings indicate that LASSBio-2052 is a promising prototype for further in vivo studies.

Discovery of Novel N-Acylhydrazone Derivatives as Potent Inhibitors of Sirtuin-1

AbstractSIRT1 enzyme is a key family member of Silent Information Regulators (Sirtuins), which catalyze the deacetylation of proteins. Therefore, developing new SIRT1 inhibitors has potential application in treating cancer disease and age-related metabolic disorders. In this study, we synthesized a series of N-acylhydrazone (NAH) derivatives and performed high-throughput screening of their inhibitory activity against the recombinant SIRT1 protein by a luminescent assay. Using in silico screening, we identified a new NAH derivative that features both selectivity and a high binding affinity towards the active pocket of SIRT1 that are comparable to known inhibitors such as Ex527 and Sirtinol. Such high binding affinity makes the new derivatives promising alternatives to the available inhibitors and holds promise for developing better-targeted drugs against SIRT1 activity.

Synthesis and Characterization of New N-acyl Hydrazone Derivatives of Carprofen as Potential Tuberculostatic Agents.

N-acyl hydrazone (NAH) is recognized as a promising framework in drug design due to its versatility, straightforward synthesis, and attractive range of biological activities, including antimicrobial, antitumoral, analgesic, and anti-inflammatory properties. In the global context of increasing resistance of pathogenic bacteria to antibiotics, NAHs represent potential solutions for developing improved treatment alternatives. Therefore, this research introduces six novel derivatives of (EZ)-N'-benzylidene-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide, synthesized using a microwave-assisted method. In more detail, we joined two pharmacophore fragments in a single molecule, represented by an NSAID-type carprofen structure and a hydrazone-type structure, obtaining a new series of NSAID-N-acyl hydrazone derivatives that were further characterized spectrally using FT-IR, NMR, and HRMS investigations. Additionally, the substances were assessed for their tuberculostatic activity by examining their impact on four strains of M. tuberculosis, including two susceptible to rifampicin (RIF) and isoniazid (INH), one susceptible to RIF and resistant to INH, and one resistant to both RIF and INH. The results of our research highlight the potential of the prepared compounds in fighting against antibiotic-resistant M. tuberculosis strains.

N-Acylhydrazone Pharmacophore's Analgesic and Anti-inflammatory Profile: Recent Advancements during the Past Ten Years.

Due to its important biological and pharmacological properties, in the field of medicinal chemistry and drug discovery, the N-acylhydrazone motif has shown to be extremely adaptable and promising. This scaffold has become a crucial component in the synthesis of numerous bioactive agents. N-Acylhydrazones are also interesting biological and synthetic tools due to their easy and straightforward synthesis. The current review provides a summary of the analgesic and anti-inflammatory activities of N-acylhydrazone derivatives over the past ten years. A brief discussion of structure-activity relationships is also provided which may guide researchers in medicinal chemistry to develop derivatives based on N-acylhydrazone scaffold as potent anti-inflammatory candidates.

Coumarin N-Acylhydrazone Derivatives: Green Synthesis and Antioxidant Potential-Experimental and Theoretical Study.

Coumarin N-acylhydrazone derivatives were synthesized in the reaction of 3-acetylcoumarin and different benzohydrazides in the presence of molecular iodine as catalyst and at room temperature. All reactions were rapidly completed, and products were obtained in good to excellent yields. It is important to emphasize that four products were reported for the first time in this study. The obtained compounds were subjected to evaluation of their in vitro antioxidative activity using DPPH, ABTS, and FRAP methods. It was shown that products with a catechol moiety in their structure are the most potent antioxidant agents. The thermodynamic parameters and Gibbs free energies of reactions were used to determine the most probable mechanism of action. The results of in silico examination emphasize the need to take solvent polarity and free radical species into account when examining antiradical action. It was discovered by using computational approaches that HAT and SPLET are competitive molecular pathways for the radical scavenging activity of all compounds in polar mediums, while the HAT is the dominant mechanism in non-polar environments.

Synthesis, Biological, Spectroscopic and Computational Investigations of Novel N-Acylhydrazone Derivatives of Pyrrolo[3,4-d]pyridazinone as Dual COX/LOX Inhibitors.

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c-7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins-AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability.

Anticancer agents incorporating the N-acylhydrazone scaffold: Progress from 2017 to present.

The N-acylhydrazone motif has been shown to be particularly adaptable and promising in the area of medicinal chemistry and drug development, due to its significant biological and pharmacological characteristics. Moreover, N-acylhydrazones are appealing synthetic and biological tools because of their simple and straightforward synthesis. This scaffold has emerged as a fundamental building block for the synthesis of bioactive compounds. Particularly, the N-acylhydrazone scaffold served as a base for the synthesis of a number of potent anticancer agents acting via different mechanisms. An updated summary of the anticancer activity of N-acylhydrazone derivatives described in the literature (from 2017 to 2022) is provided in the current review. It discusses the structure-activity relationship (SAR) of N-acylhydrazone derivatives exhibiting anticancer potential, which could be helpful in designing and developing new derivatives as effective antiproliferative candidates in the future.

In silico studies and antimicrobial investigation of synthesised novel N-acylhydrazone derivatives of indole

Indole is an exceptional scaffold in the discovery and design of drugs with different mechanisms and biological activity. Numerous research has been conducted on N-acylhydrazones of indole and its derivatives, however, no account of the synthesis, molecular docking and the antimicrobial activities of the eleven synthesised compounds has never been reported. The study was therefore designed to synthesize, characterize, carry out molecular docking and determine the antimicrobial activities of novel N-acylhydrazone derivatives of indole.Aldol condensation of synthesised hydrazides with aromatic aldehydes led to the formation of the N-acylhydrazone derivatives of indole. The structure of the compounds were confirmed by proton nuclear magnetic Resonance (1H NMR) and electron impact mass spectrometry (EIMS). The N-acylhydrazones were screened against ten microbes (four fungi three Gram-positive bacteria, and three Gram-negative bacteria) at concentrations of 100 to 6.26 mg/mL, using agar well diffusion and fungi carpeted antimicrobial assays. Gentamicin (5 mg/mL) was the positive control for bacteria while tioconazole (70%) was used for fungi. The molecular docking studies was done and the docking scores recorded accordingly on four antimicrobial receptors with PDB codes (3CR7, 3FHV, 6L1L and 6SPC).The synthesised compounds displayed moderate activity against the test organisms with the zone of inhibitions range 24 ± 0.00 to 18 ± 0.70 mm at 100 mg/mL as compared to the standards (gentamicin 10 µg/mL (36 ± 1.41), tioconazole 70% (26 ± 4.24)). All synthesised N-acylhydrazone derivatives exhibited a good number of hydrophobic interactions, classical and non-classical hydrogen bonding with the docked protein enzymes. Compound 10 and 1 were predicted to exhibit highest binding energy of -9.7 and -9.2 kcal/mole respectively with the binding site of 6SPC. Other compounds were found to have higher predicted binding energies than the standard drugs. Previously, there has been no report on the synthesis of N-acylhydrazone derivatives of Indole used in this study, their molecular docking and antimicrobial analyses is being reported for the first time. Since microbial resistance poses a major threat to human health globally, this research screened the synthesised compounds on fungi and bacteria and were found to be active against the selected microbes. These compounds if ameliorated, will reduce the uncontrollable rise in the multidrug-resistant (MDR) bacteria in Africa and in the universe.Therefore, since the synthesised N-acylhydrazone derivatives have potential in inhibiting microbial growth and showed good binding parameters with the tested enzymes, they could be effectively developed into antimicrobial agents useful for treating a wide range of microbial infections. Further research should conducted on the drugability, toxicity, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the drug compounds.

A Review of Biological Applications of Transition Metal Complexes Incorporating N-acylhydrazones

Abstract: In view of the crucial importance of the bioactivities of N-acylhydrazone derivatives and their corresponding metal complexes, N-acylhydrazones have recently attracted the attention of researchers in the chemical, biological, and pharmaceutical fields. This review aims to describe Nacylhydrazone complexes involving transition metal ions, such as copper, chromium, manganese, iron, cobalt, nickel, and zinc, and investigate their properties and possible applications in various domains. The most promising applications of the number of transition metal complexes incorporating Nacylhydrazones in biology, medicine, and pharmacology are also examined and determined.

Evaluation of antiplasmodial activity in silico and in vitro of N-acylhydrazone derivatives

N-acylhydrazones are considered privileged structures in medicinal chemistry, being part of antimicrobial compounds (for example). In this study we show the activity of N-acylhydrazone compounds, namely AH1, AH2, AH4, AH5 in in vitro tests against the chloroquine-resistant strain of Plasmodium falciparum (W2) and against WI26 VA-4 human cell lines. All compounds showed low cytotoxicity (LC50 > 100 µM). The AH5 compound was the most active against Plasmodium falciparum, with an IC50 value of 0.07 μM. AH4 and AH5 were selected among the tested compounds for molecular docking calculations to elucidate possible targets involved in their mechanism of action and the SwissADME analysis to predict their pharmacokinetic profile. The AH5 compound showed affinity for 12 targets with low selectivity, while the AH4 compound had greater affinity for only one target (3PHC). These compounds met Lipinski's standards in the ADME in silico tests, indicating good bioavailability results. These results demonstrate that these N-acylhydrazone compounds are good candidates for future preclinical studies against malaria.Graphical

Acridine Based N-Acylhydrazone Derivatives as Potential Anticancer Agents: Synthesis, Characterization and ctDNA/HSA Spectroscopic Binding Properties.

A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA—ctDNA and human serum albumin—HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M−1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M−1, Kb = 2.54 M−1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro act as potential dual inhibitors of hTopo I and II with a partial effect on the metabolic activity of cancer cells A594. The acridine-benzohydrazides 3a and 3c reduced the clonogenic ability of A549 cells by 72% or 74%, respectively. The general results of the study suggest that the novel compounds show potential for future development as anticancer agents.

Synthesis, Molecular Docking and Biological Evaluation of Napthyl N-Acyl Hydrazone Derivatives

A series of 2-(benzamido)-N′-((naphthalen-1-yl)methylene)-3-(substituted phenyl)acrylo hydrazides (4a-m, 5a-b) were synthesized by condensation of 2-(benzamido)-3-(substituted phenyl)acrylohydrazides with 1-naphthaldehyde in presence of few drops of acetic acid in ethanol. Structural elucidation of final compounds was confirmed by spectral data. Title compounds were evaluated for antioxidant and antibacterial activities and subjected to in silico studies and molecular docking studies with cyclooxygenase-II (COX-II, PDB I’d: 3LN1) and active compounds from docking studies were selected for in vivo evaluation of their antiinflammatory activity. Among the series, compound 4i showed good antioxidant activity; 5b showed good antibacterial activity. All the six derivatives with good docking scores were selected for in vivo evaluation of their antiinflammatory activity. Among the selected active compounds from docking studies, compound 4m showed good antiinflammatory activity which is comparable with that of standard drug diclofenac. In silico studies indicated that all the compounds followed Lipinski’s rule and exhibited good oral absorption and bioavailability.

Effect of S-Se Bioisosteric Exchange on Affinity and Intrinsic Efficacy of Novel N-acylhydrazone Derivatives at the Adenosine A2A Receptor.

In this work, we evaluated the conformational effect promoted by the isosteric exchange of sulfur by selenium in the heteroaromatic ring of new N-acylhydrazone (NAH) derivatives (3–8, 13, 14), analogues of the cardioactive compounds LASSBio-294 (1) and LASSBio-785 (2). NMR spectra analysis demonstrated a chemical shift variation of the iminic Csp2 of NAH S/Se-isosters, suggesting a stronger intramolecular chalcogen interaction for Se-derivatives. To investigate the pharmacological profile of these compounds at the adenosine A2A receptor (A2AR), we performed a previously validated functional binding assay. As expected for bioisosteres, the isosteric-S/Se replacement affected neither the affinity nor the intrinsic efficacy of our NAH derivatives (1–8). However, the N-methylated compounds (2, 6–8) presented a weak partial agonist profile at A2AR, contrary to the non-methylated counterparts (1, 3–5), which appeared as weak inverse agonists. Additionally, retroisosterism between aromatic rings of NAH on S/Se-isosters mimicked the effect of the N-methylation on intrinsic efficacy at A2AR, while meta-substitution in the phenyl ring of the acyl moiety did not. This study showed that the conformational effect of NAH-N-methylation and aromatic rings retroisosterism changed the intrinsic efficacy on A2AR, indicating the S/Se-chalcogen effect to drive the conformational behavior of this series of NAH.

Design, Synthesis and Biological Evaluation of New N-Acyl Hydrazones with a Methyl Sulfonyl Moiety as Selective COX-2 Inhibitors.

The mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs) is inhibition of specific prostaglandin (PG) synthesis by inhibition of cyclooxygenase (COX) enzymes. The two COX isoenzymes show 60 % similarity. It is known that the nonspecific side effects of conventional NSAIDs are physiologically caused by inhibition of the COX-1 enzyme. Therefore, the use of COX-2 selective inhibitors is seen to be a more beneficial approach in reducing these negative effects. However, some of the existing COX-2 selective inhibitors show cardiovascular side effects. Therefore, studies on the development of new selective COX-2 inhibitors remain necessary. It is important to develop new COX-2 inhibitors in the field of medicinal chemistry. Accordingly, novel N-acyl hydrazone derivatives were synthesized as new COX-2 inhibitors in this study. The hydrazone structure, also known for its COX activity, is important in terms of many biological activities and was preferred as the main structure in the design of these compounds. A methyl sulfonyl pharmacophore was added to the structure in order to increase the affinity for the polar side pocket present in the COX-2 enzyme. It is known that methyl sulfonyl groups are suitable for polar side pockets. The synthesis of the compounds (3a-3j) was characterized by spectroscopic methods. Evaluation of in vitro COX-1/COX-2 enzyme inhibition was performed by fluorometric method. According to the enzyme inhibition results, the obtained compounds displayed the predicted selectivity for COX-2 enzyme inhibition. Compound 3j showed important COX-2 inhibition with a value of IC50 =0.143 uM. Interaction modes between the COX-2 enzyme and compound 3j were investigated by docking studies.

Synthesis, Characterization and computational study of N-Acylhydrazone derivatives.

Abstract The N-Acylhydrazone of benzoic acid and their derivatives are important intermediates in organic synthesis and have widespread applications in the medicinal industry. The N-Acylhydrazone was prepared through the condensing of the phenyl hydrazide derivatives which prepared from phenylmethyl ester, with benzaldehyde and then identified by physicochemical properties and spectral analysis; FT-IR and 1HNMR. Computation calculations studies by using Semi-empirical-PM3 method through a molecular structure with optimized geometry showed that there is a high correlation between dipole moment, Electron affinity (EA), ionization potential (IP), electronegativity, ClogP and hardness. To Proof, the stability of N-Acylhydrazone derivatives by using Molecular orbital calculations supported a full description of the orbitals and the contributions of individual atoms. Highest occupied molecular orbital/lowest unoccupied molecular orbital energies and structures are demonstrated, calculation atomic charge and molecular electrostatic potential. Through the data obtained from the computational chemistry program, Hyper Chem 8,we were able to demonstrate that the N-acylhydrazone derivatives have a close value and within the limits of stability.

New class of hantaan virus inhibitors based on conjugation of the isoindole fragment to (+)-camphor or (−)-fenchone hydrazonesv

This work presents the design and synthesis of camphor, fenchone, and norcamphor N-acylhydrazone derivatives as a new class of inhibitors of the Hantaan virus, which causes haemorrhagic fever with renal syndrome (HFRS). A cytopathic model was developed for testing chemotherapeutics against the Hantaan virus, strain 76–118. In addition, a study of the antiviral activity was carried out using a pseudoviral system. It was found that the hit compound possesses significant activity (IC50 = 7.6 ± 2 µM) along with low toxicity (CC50 > 1000 µM). Using molecular docking procedures, the binding with Hantavirus nucleoprotein was evaluated and the correlation between the structure of the synthesised compounds and the antiviral activity was established.

A Simple Isoniazid-Based N-Acylhydrazone Derivative as Potential Fluorogenic Probe for Zn2+ Ions.

This study evaluated three isoniazid-based N-acylhydrazone derivatives (HL1, HL2, and HL3) varying their substituting groups (-H, -N(CH3)2, and -NO2) as potential chemosensors for Zn2+ ions. To this end, the absorption and emission properties of these derivatives were investigated in the presence of Zn2+ ions. Results point to the derivative HL2 as the best chemosensor for Zn2+ ions because of its comparatively higher sensitivity. The color of this derivative changed from colorless to strong yellow with zinc addition, as indicated by the shift in UV-vis spectrum. Moreover, HL2 was the only derivative to emit fluorescence in the presence of Zn2+ ions, attributable to PET inhibition and bond isomerization promoted by coordination with this metal. LOD, LOQ, and binding constant values for HL2 + Zn2+ were 0.43μmol.l-1, 0.93μmol.l-1, and 5.04 × 1012l.mol-1, respectively. The fluorescence of HL2 with other metal ions (Fe3+, Mg2+, Na+, Cd2+, Cu2+, Co2+, Ni2+, Ca2+, and K+) was also investigated. Zn2+ yielded the best result without Cd2+ interferences. Job's Plot showed that the stoichiometric ratio of the complex formed by HL2 and Zn2+ ions is 2:1 (ligand:metal). The strip test with adsorbed HL2 indicated fluorescence in the presence of zinc ions under 365nm UV irradiation.