Dibenzoylhydrazine Research Articles

Bioimaging of hypochlorous acid using a near-infrared fluorescent probe derived from rhodamine dye with a large Stokes shift

Hypochlorous acid (HClO) is a bioactive molecule that bears an important function in various physiological and pathological processes such as cell signal transduction, pathogen invasion, and redox balance regulation. The near-infrared (NIR) fluorescent probe with a large Stokes shift for bioimaging of HClO is envisioned to outperform other fluorescence probes with following advantages: greater penetration depth, smaller overlap between emission and absorption spectra, and greater reduction in false results caused by the excitation light and the scattered light, aiming to achieve selective and sensitive bioimaging of HClO in vivo. Herein, a NIR fluorescent probe, TJM, was synthesized by modifying the structure of rhodamine dye to make it water soluble and biocompatible for living cells. Under being excited at 585 nm, TJM exhibits an emission peak at 730 nm with a large Stokes shift of 145 nm. TJM also provides a fast NIR fluorescent response to HClO with excellent selectivity, high sensitivity, and low detection limit (0.11 μM). The fluorescence intensity of TJM is triggered by HClO based on HClO-induced oxidization of dibenzoyl hydrazine to dibenzoyl diimide, allowing imaging of HClO in living cells, zebrafish, and different disease mice models. TJM has been demonstrated a suitable NIR probe for imaging endogenous HClO in biological systems.

Nonsteroidal ecdysone receptor agonists use a water channel for binding to the ecdysone receptor complex EcR/USP.

The ecdysone receptor (EcR) possesses the remarkable capacity to adapt structurally to different types of ligands. EcR binds ecdysteroids, including 20-hydroxyecdysone (20E), as well as nonsteroidal synthetic agonists such as insecticidal dibenzoylhydrazines (DBHs). Here, we report the crystal structures of the ligand-binding domains of Heliothis virescens EcR/USP bound to the DBH agonist BYI09181 and to the imidazole-type compound BYI08346. The region delineated by helices H7 and H10 opens up to tightly fit a phenyl ring of the ligands to an extent that depends on the bulkiness of ring substituent. In the structure of 20E-bound EcR, this part of the ligand-binding pocket (LBP) contains a channel filled by water molecules that form an intricate hydrogen bond network between 20E and LBP. The water channel present in the nuclear receptor bound to its natural hormone acts as a critical molecular adaptation spring used to accommodate synthetic agonists inside its binding cavity.

Synthesis of Zirconia Doped Molybdenum Oxide as Efficient Catalysts for Ultrasound Assisted Synthesis of Substituted Pyrazoles

To explore green methodology for the synthesis of mixed oxide, its catalytic activity and temperature stability of series of ZrO2/MoO3 and ZrO2 were prepared by sol-gel method and characterized by XRD, FT-IR, X-ray photoelectron spectroscopy (XPS), temperature programmed Desorption (TPD), Raman spectroscopy and transmission electron microscopes (TEM). These mixed oxides were showed high stability with nanocrystalline nature. Due to highly acidic nature of the catalysts, ultra sound assisted synthesis of substituted pyrazoles was carried out successfully with high yield. The reaction was carried out in solvent free medium, which showed green approach and energy saving reaction. Condensation of dibenzoyl methane and hydrazine to form substituted pyrazoles with 97.7% yield. The acid strength and acid amount of synthesized catalysts were determined by temperature programmed desoprtion (TPD), incorporation of zirconia into the molybdenum, network has changed its surface acid properties due to the Zr2+ and Mo6+ ions. After addition of ZrO2 on MoO3, it showed weak and strong acid sites.

Novel polymaleimide containing dibenzoyl hydrazine pendant group as chelating agent for antimicrobial activity

ABSTRACTNovel polymaleimide containing dibenzoyl hydrazine pendant group, poly[N-benzoyl-4-(N-maleimido)-phenyl hydrazide], and its metal complexes have been synthesized. Their antimicrobial activity against Bacillus subtilis, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli bacteria and that against Aspergillus fumigatus, Syncephalastrum racemosum, Geotrichum candidum, and Candida albicans fungi were investigated. The polymer–metal complexes showed better antimicrobial activity than that of the parent polymer. The inhibition of the growth of the microbes remarkably depends on the type of the metal in the complexes. The polymer–Co(II) and the polymer–Cd(II) complexes are more potent in inhibition of the tested microbes growth than the rest of the prepared complexes.

Exploration of the binding affinities between ecdysone agonists and EcR/USP by docking and MM-PB/GBSA approaches.

Ecdysone receptor (EcR) is a significant target in the identification of new environmentally friendly pesticides. There are two types of ecdysone agonists: steroidal ecdysone agonists and dibenzoylhydrazines (DBHs). In this study, various modeling methods (homology modeling, molecular docking, MD simulation, binding free energy calculation, and per-residue binding free energy decomposition) were utilized to study the different binding mechanisms of two types of ecdysone agonists. Our theoretical results indicated that the relative binding potencies of DBHs can be ranked sufficiently accurately using the MOE docking method. However, MM/PBSA calculations more accurately predicted the binding affinities between steroidal ecdysone agonists and EcR-LBD. To identify the key residues involved in ecdysone agonist binding, the binding free energy (ΔG Bind) was decomposed into the energy contributions of individual residues. The results revealed that nine residues-Ile339, Thr343, Met380, Met381, Tyr403, Tyr408, Asp419, Gln503, and Asn504-determined the binding affinities of the DBHs. Glu309, Met342, Arg383, Arg387, and Leu396 were important influences on the binding affinities of the steroidal ecdysone agonists. Graphical abstract The ecdysone receptor (EcR) is related to insect growth and has been shown to be a useful target for insecticides.

Structure–activity relationships of dibenzoylhydrazines for the inhibition of P-glycoprotein-mediated quinidine transport

We previously demonstrated that dibenzoylhydrazines (DBHs) are not only P-glycoprotein (P-gp) substrates, but also inhibitors. In the present study, we evaluated the inhibition of P-gp-mediated quinidine transport by two series of DBHs and performed a classical QSAR analysis and docking simulation in order to investigate the mechanisms underlying P-gp substrate/inhibitor recognition. The results of the QSAR analysis identified the hydrophobic factor as the most important for inhibitory activities, while electronic and steric effects also influenced the activities. The different substituent effects observed in each series suggested the different binding modes of each series of DBHs, which was supported by the results of the docking simulation.

In vitro and in vivo evaluations of the P-glycoprotein-mediated efflux of dibenzoylhydrazines

P-glycoprotein (P-gp) is a member of the ATP-binding cassette transporter family. It actively transports a wide variety of compounds out of cells to protect humans from xenobiotics. Thus, determining whether chemicals are substrates and/or inhibitors of P-gp is important in risk assessments of pharmacokinetic interactions among chemicals because P-gp-mediated transport processes play a significant role in their absorption and disposition. We previously reported that dibenzoylhydrazines (DBHs) such as tebufenozide and methoxyfenozide (agrochemicals) stimulated P-gp ATPase activity. However, it currently remains unclear whether these derivatives are transport substrates of P-gp and inhibit transport of other chemicals by P-gp.In the present study, in order to evaluate the interactions of DBHs with other chemicals in humans, we determined whether DBHs are P-gp transport substrates using both the in vitro bidirectional transport assay and the in vivo study of rats. In the in vivo study, we investigated the influence of P-gp inhibitors on the brain to plasma ratio of methoxyfenozide in rats. We also examined the inhibitory effects of DBHs on quinidine (a P-gp substrate) transport by P-gp in order to ascertain whether these derivatives are inhibitors of P-gp. Based on the results, DBHs were concluded to be weak P-gp transport substrates and moderate P-gp inhibitors. However, the risk of DBHs caused by interaction with other chemicals including drugs was considered to be low by considering the DBHs' potential as the substrates and inhibitors of P-gp as well as their plasma concentrations as long as DBHs are properly used.

A new dibenzoylhydrazine with insecticidal activity against Anopheles mosquito larvae

Dibenzoylhydrazine (DBH) compounds have been applied successfully as environmentally safe insecticides against lepidopteran larvae and ground-dwelling coleopterans, but their potential to combat mosquito larvae is largely unknown. Here, toxicity tests of three commercial DBHs (tebufenozide, methoxyfenozide and halofenozide) and one experimental DBH (KU-106) against larvae of Anopheles gambiae, the major vector for human malaria, are reported. Based on calculated median larvicidal concentration (LC50 ) values at 5 days of treatment, KU-106 (760 nM) showed an activity against Anopheles larvae similar to that of commercial halofenozide. Induction of the early-late gene hr3 and docking studies of DBHs in the ligand-binding pocket of the modelled Anopheles ecdysone receptor indicated that toxicity is caused by the activation of the ecdysone regulatory cascade causing a premature lethal moult. As a result of the similar toxicity exhibited by the experimental compound KU-106 to that shown by commercial products, the present study demonstrated that the use of DBH compounds to combat harmful dipteran insects, such as mosquitoes, remains unexplored and invites further systematic toxicity tests using other derivatives of the DBH class of compounds.

Towards Coleoptera-specific high-throughput screening systems for compounds with ecdysone activity: development of EcR reporter assays using weevil ( Anthonomus grandis)-derived cell lines and in silico analysis of ligand binding to A. grandis EcR ligand-binding pocket

Molting in insects is regulated by ecdysteroids and juvenile hormones. Several synthetic non-steroidal ecdysone agonists are on the market as insecticides. These ecdysone agonists are dibenzoylhydrazine (DBH) analogue compounds that manifest their toxicity via interaction with the ecdysone receptor (EcR). Of the four commercial available ecdysone agonists, three (tebufenozide, methoxyfenozide and chromafenozide) are highly lepidopteran specific, one (halofenozide) is used to control coleopteran and lepidopteran insects in turf and ornamentals. However, compared to the very high binding affinity of these DBH analogues to lepidopteran EcRs, halofenozide has a low binding affinity for coleopteran EcRs. For the discovery of ecdysone agonists that target non-lepidopteran insect groups, efficient screening systems that are based on the activation of the EcR are needed. We report here the development and evaluation of two coleopteran-specific reporter-based screening systems to discover and evaluate ecdysone agonists. The screening systems are based on the cell lines BRL-AG-3A and BRL-AG-3C that are derived from the weevil Anthonomus grandis, which can be efficiently transduced with an EcR reporter cassette for evaluation of induction of reporter activity by ecdysone agonists. We also cloned the almost full length coding sequence of EcR expressed in the cell line BRL-AG-3C and used it to make an initial in silico 3D-model of its ligand-binding pocket docked with ponasterone A and tebufenozide.

QSAR and mode of action studies of insecticidal ecdysone agonists†

A series of our SAR and QSAR studies of synthetic moulting hormone agonists, dibenzoylhydrazines (DBH), exhibiting insecticidal/larvicidal activity are reviewed in this article. We prepared a number of analogues where various substituents are introduced into the two benzene rings of DBH and measured their biological activity using various biological systems. Larvicidal activity was against larvae of the rice stem borer Chilo suppressalis and the moulting hormone activity was in terms of the stimulation of N-acetylglucosamine incorporation in a cultured integument system of the same insect species. Binding affinity to the ecdysone receptor was assayed with intact Sf-9 cell lines in which the ADME processes are negligible as well as using receptor proteins obtained by in vitro translation of the responsible cDNA cloned from cell-free preparation of integumentary tissue of C. suppressalis. Variations in the biological activity indices were either correlated between two types of activity or correlated using physicochemical molecular and substituent parameters in terms of the classical QSAR. Comparisons among correlations and with recently revealed X-ray crystallographic findings clearly indicate the physicochemical meaning of parameters significant in the correlation equations to help understanding molecular mechanism of the moulting hormonal action. †Presented at the 12th International Workshop on Quantitative Structure-Activity Relationships in Environmental Toxicology (QSAR2006), 8--12 May 2006, Lyon, France.

Synthesis and crystal structure of N-tert-butyl-N′-thio [O-(1-methylthioethylimino)-N″-methylcarbamic acid]-N,N′-dibenzoylhydrazine

The novel compound N-tert-butyl-N′-thio[O-(1-methylthioethylimino)-N″-methyl carbamic acid]- N,N′-dibenzoylhydrazine has been synthesized by the reaction of N-tert-butyl-N,N′-dibenzoylhydrazine with N-sulfenyl chloride of O-(1-methylthio ethylimino) -N-methylcarbamic acid. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic, space group P2(1)/n with the following crystallographic parameters: a = 7.569(3) A, b = 20.585(7) A, c = 16.347(5) A, α = 90∘, β = 92.606(6)∘, γ = 90∘, V = 2544.4(14) A3, z = 4, Dx = 1.276 mg/m3, F(000) = 1032, T = 293(2) K, 2.34∘≤ θ≤ 25.01∘, the final R factor: R 1 = 0.0475, wR 2 = 0.0907. The N–N bond adopts a gauche conformation with a dihedral angle(φ) of 98.8∘ for C(17)=N(1)=N(2)=C(7), whereas its parent compound N-tert-butyl-N,N′-dibenzoyl hydrazine has the dihedral angle of −71.8∘.

20-hydroxyecdysone receptor ligand binding domain: 1. A semiempirical study of dibenzoylhydrazines selectivity

Dibenzoylhydrazine (DBH) pesticides, such as RH5849 and RH2485, are non-steroidal agonists of the insect hormone 20-hydroxyecdysone (20E) that exert their insecticidal effect by interaction with the 20E receptor (EcR). Differently from RH5849, RH2485 is selectively toxic to lepidopteran species. In this work, we evaluate by the semiempirical methodology the structures and energetics of the complexes between RH5849 and RH2485 and models of Lepidoptera and Diptera EcRs. Models were constructed by homology modeling of the EcR binding region of the lepidopteran Manduca sexta and of the dipteran Drosophila melanogaster. A preliminary study of the interaction between the models and the natural agonist was implemented. The calculated enthalpy associated with the binding forces between synthetic agonists and simplified receptor models presented qualitative agreement with the biological profile of the DBHs towards Lepidoptera and Diptera. A rationale for the observed differences in the pesticide activities of RH5849 and RH2485 based on the structures of the modeled complexes is presented.

Ecdysteroid receptor binding activity and ecdysteroid agonist activity at the level of gene expression are correlated with the activity of dibenzoyl hydrazines in larvae of Bombyx mori

Ecdysteroid activities of two dibenzoyl hydrazines (RH 5849 and RH 5992) were examined using the Kc cell line. Gene expression activity was determined in the transient assay utilizing the ecdysteroid responsive Drosophila melanogaster hsp27 promoter gene. Ecdysteroid receptor binding (EC 50 = 3.0 × 10 −7 m), induction of ecdysteroid responsive gene expression (EC 50 = 3.0 × 10 −6 m) and induction of cell morphological change (EC 50 = 3.0 × 10 −7 m) were 13-fold, 7-fold and 13-fold higher in RH 5992 than in RH 5849, respectively. The addition of 10 ppm RH 5849 to the diet induced head capsule slippage in Bombyx mori larvae and most of the larvae died. RH 5992 caused the same response at 1 ppm. The higher insecticidal activity of RH 5992 compared to RH 5849 is likely caused by its higher ecdysteroid agonist activity at the molecular level.

A Novel Ecdysteroid Responsive Reporter Plasmid Regulated by the 5'-Upstream Region of the Drosophila melanogaster (Diptera: Drosophilidae) Acetylcholinesterase Gene

Acetylcholinesterase activity induction by ecdysteroids is known in Drosophila melanogaster Kc cells, but its induction at the gene expression level has not been studied. A reporter plasmid was constructed by ligation of the D. melanogaster acetylcholinesterase gene (Ace gene) 5'-upstream 1.62 kb region to firefly luciferase cDNA. The plasmid was then introduced into Kc cells by the electroporation method for induction study. With the addition of 1.0 × 10-8 M 20-hydroxyecdysone, a 4-fold induction of luciferase was observed 72 h after the hormone treatment, while 1.0 × 10-6 M ecdysone was required to give a 5-fold induction. Dibenzoyl hydrazines (RH 5849 and RH 5992), which are known as non-steroidal ecdysteroid agonists, also induced a 3 to 4-fold induction, whoever, RH 5992 showed a higher induction potential than RH 5849 (as in other ecdysteroid assays). These results suggest that this novel ecdysteroid responsive reporter plasmid (system) might be useful for the evaluation of ecdysteroids and further analysis of the acetylcholinesterase induction mechanism by ecdysteroids.

Molecular analysis of the mode of action of RH-5992, a lepidopteran-specific, non-steroidal ecdysteroid agonist

The dibenzoyl hydrazine, RH-5992, induces precocious molting in all lepidopteran larvae tested including the tobacco hornworm, Manduca sexta and the spruce budworm, Choristoneura fumiferana. Synthesis of a new cuticle including formation of a new head capsule that is incompletely sclerotized and lack of ecdysis are some of the major phenotypic effects. Similar to 20E, RH-5992 induces Manduca hormone receptor 3 (MHR3) mRNA and suppresses 14 kDa larval cuticular protein (LCP-14) transcript levels in 4th instar epidermis of Manduca, cultured in vitro. The ED 50 for induction of MHR3 was 1.4 × 10 −7 M, 10 times less than that of 20E. When the epidermis was exposed to 20E for 17 h and then cultured in hormone-free medium for a further 48 h, the LCP-14 mRNA level went up to nearly 60% of the maximal level reached in the untreated control. However, when RH-5992 was used, the level remained low even after 48 h. Dopa decarboxylase (DDC) transcription normally occurs at the end of the molt in preparation for sclerotization and in the epidermis cultured in vitro requires initial exposure to 20E for 17 h followed by its removal. Both in vivo and transient in vitro treatment with RH-5992 prevented DDC expression for up to 48 h after the removal of the compound. Thus, RH-5992 mimics the action of 20E on the expression of these 3 genes, but its effects persist in the tissue much longer than 20E.

Non‐steroidal ecdysteroid agonists: Tools for the study of hormonal action

AbstractThe first non‐steroidal ecdysteroid agonists are dibenzoyl hydrazines and are typified by the compounds designated RH‐5849 and RH‐5992. The discovery that these compounds mimic 20E in a variety of insect orders, and especially the Lepidoptera, generated great interest from the research and agricultural communities. Such compounds provide important new research tools for physiological, biochemical, and molecular studies. In addition, the potential for application to agricultural pests looks very promising, especially for RH‐5992 (tebufenozide). This review evaluates the evidence on the specificity of the ecdysteroid‐like actions of these materials and considers their application for research and pest management. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of Amerira.

Thermodynamics of synthesis of poly-( p, p′-diphenyleneoxido)-1,3,4-oxadiazole by intramolecular cyclodehydration of poly-( p, p′-diphenyleneoxido)-hydrazide

The enthalpy, entropy and Gibbs free energy of thermal cyclization of poly( p, p′-diphenyleneoxido)hydrazide (PA) to poly-( p, p′-diphenylenoxido)-1,3,4-oxadiazole (POD), have been determined. For this purpose the heat capacity of PH and POD was studied over the temperature range of 60–600°K, the standard enthalpy of combustion of these polymers was determined and the equilibrium water vapour pressure over PH during its cyclodehydration measured. Analysis of the results led to the conclusion that the reaction PH → POD + H 2O occurs at an appreciable rate only above the glass temperature of PH, where the mobility of the segments of the polymer chain increases sharply. Similar measurements and calculations were made for N,N′-dibenzoylhydrazine (DBH) and 2,5-diphenyl-1,3,4-oxidiazole (DOD), which serve as models of the repeating units of the polymers studied. It is shown that with the model compounds, which are molecular crystals, the reaction DBH → DOD + H 2O occurs only above the melting point of DBH.

Structure of donor-acceptor complexes—XI. Compounds of diacetyl and dibenzoyl hydrazines with some group (III) halides

Structure of donor-acceptor complexes—XI. Compounds of diacetyl and dibenzoyl hydrazines with some group (III) halides