Benzalacetone Research Articles

Synthesis and catalytic activity of tetradentate β-diketiminato rare-earth metal monoalkyl complexes in tandem Oppenauer oxidation and cross-aldol condensation.

A series of unsymmetric tetradentate β-diketiminato rare-earth metal monoalkyl complexes were synthesized, and their catalytic behavior has been well developed. Indole-incorporated β-diketiminato proligands H2L (L = MeC(NDipp)CHC(Me)NCH2CH2-3-(1-R-C8H4N), R = CH2-(2-C4H7O), L1; R = (CH2)2OMe, L2; Dipp = 2,6-iPr2C6H3) were prepared by the reaction of an arylamino-enone with 1-substituted-tryptamine in good yields. Treatment of the proligands with the rare-earth metal trialkyl complexes RE(CH2SiMe3)3(THF)2 generated the corresponding unsymmetric N,N,C,O-tetradentate β-diketiminato rare-earth metal monoalkyl complexes LRE(CH2SiMe3) (L1, RE = Y (1a), Gd (1b), Yb (1c), Lu (1d); L2, RE = Y (2a), Gd (2b), Yb (2c), and Lu(2d)). During the process, the activation of the sp2 C-H bond at the 2-position of the indole ring led to the formation of an unprecedented β-diketiminato dianion L2-, bonding to the rare-earth metal ions in a chelating N,N,C,O-tetradentate manner. Further studies indicated that these tetradentate rare-earth metal complexes could initiate the Oppenauer oxidation of secondary alcohols into the corresponding ketones in high yields. In the case of primary alcohols, a tandem Oppenauer oxidation and cross-aldol condensation occurred unexpectedly. Various α-mono-substituted benzylidene acetones, α,α'-bis-substituted benzylidene acetones and cyclohexanones were obtained under mild conditions only by controlling the molar ratio of alcohols to ketones. Notably, all these alkenylation ketones exhibited exclusive E configuration.

Assessment of Groundwater Quality in Owerri and Its Environments, Southeast Nigeria

Physico-Chemical and bacteriological characteristics of eleven boreholes located within Owerri city were examined. The bacteriological analyses were carried out using the method of inoculation and incubation of specimens and counted on colonies. Titration method was used to determine chlorides and nitrates while Cu2+, Zn2+ and Mn2+ used atomic absorption spectroscopy (AAS). Iron concentration was read off using benzylideneacetone (BDA) Lovibondcolour comparator while the total dissolved solids were determined gravimetrically. The water is usually clear at average temperature of 27˚C. The bacteriological parameters are within the acceptable World Health Organization (WHO) standard and safe for human consumption. The pH is 6.0 -7.5, total dissolved solids vary from 12.4mg/l to 49.4mg/l. The anions of chloride and nitrate are 67mg/L to 125mg/L and 0.003 mg/L to 23.1 mg/L respectively. Concentrations of cations include iron; 1.86mg/l, copper; 1.2mg/l, zinc; 2.1mg/l and manganese; 0.05mg/l. The results show that the groundwater within the city is suitable for drinking and other uses compared to the WHO standard. The environmental conditions of the borehole locations as well as the total drill depth should be emphasized. Government monitoring agency should ensure adequate drill depth to at least 200ft in the south- western area and north- eastern areas from 250ft to 300ft as this may reduce the injurious variations in the geochemical parameters in some boreholes.

Theoretical investigation of adsorption characteristics of typical additives for zinc electroplating.

Electroplated zinc layers have shown excellent corrosion resistance, especially those are stable in the atmosphere after the passivation, and therefore zinc electroplating is widely used in various fields such has mechanical, vehicle, construction, and ironware industries. Benzalacetone (BA) was reported as brighteners for zinc deposition, while polyoxyethylene nonylphenylether (NP) was used as levelers or carriers for zinc electroplating. Sodium benzoate (SB) and dispersant NNO cooperatively act as auxiliary additives. Quantum chemical parameters (QCPs) of four additives were calculated by using DFT, and MD simulations were performed. By comparing binding energies of four additives (benzalacetone (BA), sodium benzoate (SB), polyoxyethylene nonylphenylether (NP) and dispersant NNO), with Zn (001) surface, BA has the lowest binding energy, which is due to the lowest hardness parameter, and NNO has the highest binding energy, which is due to the highest dipole moment despite its small hardness parameter. For DFT calculation, NWChem was employed, which uses the Gaussian basis set. The B3LYP functional was used for exchange-correlation interaction between electrons, and the 6-311G+ (d,p) basis sets were used for all the atoms. Solvation effect was considered by using COSMO (COnductor-like Screening MOdel), in which the dielectric constant of solvent was set to 78.54 of water. For dispersion correction, DFT-D method of Tkatchenko and Scheffler (TS) was used. MD simulations were performed by using GULP (General Utility Lattice Program) code with Dreiding forcefield and atomic Hirshfeld charges from DFT calculations. MD simulations were performed on the conditions of NVT ensemble with a step of 1 fs and simulation time of 500 ps at 298 K and 323 K. To consider solvation effect, 1,000 water molecules were inserted into the box.

Site-directed mutagenesis enhances the activity of benzylidene acetone synthase of polyketide synthase from Polygonum cuspidatum

Polygonum cuspidatum polyketide synthase 1 (PcPKS1) has the catalytic activity of chalcone synthase (CHS) and benzylidene acetone synthase (BAS), which can catalyze the production of polyketides naringenin chalcone and benzylidene acetone, and then catalyze the synthesis of flavonoids or benzylidene acetone. In this study, three amino acid sites (Thr133, Ser134, Ser33) that may affect the function of PcPKS1 were identified by analyzing the sequences of PcPKS1, the BAS from Rheum palmatum and the CHS from Arabidopsis thaliana, as well as the conformation of the catalytic site of the enzyme. Molecular modification of PcPKS1 was carried out by site-directed mutagenesis, and two mutants were successfully obtained. The in vitro enzymatic reactions were carried out, and the differences in activity were detected by high performance liquid chromatography (HPLC). Finally, mutants T133LS134A and S339V with bifunctional activity were obtained. In addition to bifunctional activities of BAS and CHS, the modified PcPKS1 had much higher BAS activity than that of the wild type PcPKS1 under the conditions of pH 7.0 and pH 9.0, respectively. It provides a theoretical basis for future use of PcPKS1 in genetic engineering to regulate the biosynthesis of flavonoids and raspberry ketones.

Total synthesis of (−)-Cryptofolione

Enantioselective total synthesis of δ-lactone containing natural product (−)-cryptofolione was accomplished from commercially available benzylidene acetone. Key features of the synthesis include lipase mediated resolution of a β-hydroxy ketone intermediate, DBU mediated isomerization of γ,δ-unsaturated aldehyde to α,β-unsaturated aldehyde, Brown allylation and RCM reactions.

New 2-aminopyrimidine derivatives and their antitrypanosomal and antiplasmodial activities

Novel 2-aminopyrimidine derivatives were prepared from acyclic starting materials, benzylidene acetones and ammonium thiocyanates, via 5 steps, including ring closure, aromatization, S-methylation, oxidation to methylsulfonyl compounds, and formation of guanidines with suitable amines. The prepared compounds differ from each other by the substitutions of their amino group and of their phenyl ring. The 2-aminopyrimidines were tested by use of microplate assays for their in vitro activities against a causative organism of sleeping sickness, Trypanosoma brucei rhodesiense, as well as against a causative organism of malaria, Plasmodium falciparum NF54. Their cytotoxic properties were determined with L-6 cells (rat skeletal myoblasts). Some of the compounds exhibited quite good antitrypanosomal activity, and others showed excellent antiplasmodial activity. The influence of the structural modifications on these activities is discussed.Graphic abstract

A molecular electron density theory study to understand the interplay of theory and experiment in nitrone-enone cycloaddition

[3 + 2] cycloaddition (32CA) reaction of C,N-diaryl nitrone with benzylidene acetone has been studied to analyse the mechanism, selectivity and polar character of this nitrone-enone cycloaddition. Topological analysis of the electron localization function (ELF) shows the absence of pseudoradical and carbenoid centre in the nitrone, which allows its classification as a zwitter-ionic (zw) type three atom component (TAC) and hence participation in zw- type cycloadditions is associated with high activation energy barriers. This 32CA reaction follows a one-step mechanism with asynchronous TSs. Endo/meta product is obtained as the major cycloadduct experimentally, which can be rationalized from its calculated lowest activation energy among the four possible reaction pathways. Global electron density transfer (GEDT) at the TSs predict the non-polar character of this 32CA reaction. Topological analysis of the ELF and QTAIM parameters was performed at the TSs. Finally, non-covalent interaction (NCI) gradient isosurfaces are computed to obtain a visualization of non-covalent interactions at the interatomic bonding regions. The experimental and theoretical aspects of [3+2] cycloaddition reactions of C,N-diaryl nitrone with benzylidene acetone is described. The reaction is meta/endo selective and follows one step mechanism with non-covalent interactions. The C-C and C-O bonds are generated through coupling of pseudoradical centers.

Benzylideneacetone and other phenylethylamide bacterial metabolites induce apoptosis to kill insects

Xenorhabdus and Photorhabdus are entomopathogenic bacteria that can induce immunosuppression against target insects by suppressing eicosanoid biosynthesis, leading to fatal septicemia. These bacteria can synthesize and release secondary metabolites such as benzylideneacetone (BZA) and other phenylethylamide compounds that can inhibit phospholipase A2 (PLA2) and shut down eicosanoid biosynthesis. However, insecticidal activities of these bacterial metabolites remain unclear. Thus, the objective of this study was to assess cytotoxicities of BZA and seven other bacterial metabolites to insect cells. These eight bacterial metabolites exhibited significant cytotoxicities against an insect cell line Sf9 at micromolar range. Especially, BZA and cPY were highly potent at low micromolar range. When these eight bacterial metabolites were injected to hemocoels of Spodoptera exigua larvae, they significantly decreased total count of hemocytes. In Sf9 cell line and hemocytes, these bacterial metabolites induced cell membrane blebbings, apoptotic vesicles, and genomic DNA fragmentation. Terminal deoxyribonucleotidyl transferase nick end translation assay showed that these bacterial metabolites caused significant DNA breakages in cells in a dose-dependent manner. However, a pan caspase inhibitor treatment significantly rescued the cell death induced by these bacterial metabolites. Cytotoxicities of these bacterial metabolites were highly correlated with their insecticidal activities. These results indicate that the insecticidal activities of the bacterial metabolites may be induced by their apoptotic activities against hemocytes and other insect cells. Taken together, these results suggest that phenylethylamide compounds might have potential as novel insecticides.

Secretion of secretory phospholipase A2 into Spodoptera exigua larval midgut lumen and its role in lipid digestion.

In insects, lipid digestion is controversial because insects have no bile salts to solubilize dietary lipids. One hypothesis is that a secretory type of phospholipase A2 (sPLA2 ) provides lysophospholipid (LPL) from dietary phospholipids (PLs). We identified a sPLA2 , Se-sPLA2 , in beet armyworm, Spodoptera exigua, that hydrolyses PLs at sn-2. Our goal was to investigate its role in lipid digestion. Se-sPLA2 was expressed in the entire alimentary canal. Incubating the isolated midgut in a cell culture medium led to secretion of Se-sPLA2 and other proteins. Ex vivo RNA interference (RNAi) of Se-sPLA2 expression in isolated midgut culture led to significantly decreased Se-sPLA2 secretion into the medium. Feeding double-stranded RNA specific to Se-sPLA2 to larvae suppressed sPLA2 activity in gut contents. A recombinant Se-sPLA2 was susceptible to benzylideneacetone (BZA), a specific PLA2 inhibitor. After feeding BZA to larvae, we recorded significant decreases in gut content sPLA2 activity, body growth and total haemolymph lipid contents. RNAi against Se-sPLA2 resulted in reduced digestibility. Addition of a specific LPL, 1-palmitoyl-sn-glycero-3-phosphocholine, to BZA-treated larvae rescued digestibility and larval growth. These results strongly bolster our hypothesis that Se-sPLA2 secreted from the midgut acts in lipid digestion by providing necessary LPL to solubilize dietary neutral lipids.

Ruthenium(II)-Arene Complexes of the Water-Soluble Ligand CAP as Catalysts for Homogeneous Transfer Hydrogenations in Aqueous Phase

The neutral Ru(II) complex κP-[RuCl2(η6-p-cymene)(CAP)] (1), and the two ionic complexes κP-[RuCl(η6-p-cymene)(MeCN)(CAP)]PF6 (2) and κP-[RuCl(η6-p-cymene)(CAP)2]PF6 (3), containing the water-soluble phosphine 1,4,7-triaza-9-phosphatricyclo[5.3.2.1]tridecane (CAP), were tested as catalysts for homogeneous hydrogenation of benzylidene acetone, selectively producing the saturated ketone as product. The catalytic tests were carried out in aqueous phase under transfer hydrogenation conditions, at mild temperatures using sodium formate as hydrogen source. Complex 3, which showed the highest stability under the reaction conditions applied, was also tested for C=N bond reduction from selected cyclic imines. Preliminary NMR studies run under pseudo-catalytic conditions starting from 3 showed the formation of κP-[RuH(η6-p-cymene)(CAP)2]PF6 (4) as the pivotal species in catalysis.

The Key Gold: Enhanced Platinum Catalysis for the Selective Hydrogenation of α,β-Unsaturated Ketone

AuPt alloy nanoparticles (NPs) were facilely synthesized with oleylamine as the stabilizing ligand and characterized by high-resolution transmission electron microscopy, powder X-ray diffraction, inductively coupled plasma-atomic emission spectrometer analysis, and so on. In addition, the AuPt alloys supported by the nano CeO2 exhibit high selectivity and efficiency in hydrogenation of benzylidene acetone under ambient temperature and pressure. By analyzing the catalytic performance over the NPs with different Au:Pt compositions, we found that the TONPt values (based on the number of Pt atoms) vary in the same trend with the change of conversion. Despite that gold itself shows no catalytic activity, the improved conversion and TONPt with the alloy catalysts clearly show the promotion effect of gold on the catalytic activity of the platinum. The inactive metal significantly improves the catalytic activity of active metal, which shows that the AuPt alloy exhibits an interesting synergistic effect.

Reactions of dinuclear Ni2complexes [Ni(RNPyS4)]2(RNPyS4= 2,6-bis(2-mercaptophenylthiomethyl)-4-R-pyridine) with Fe(CO)3(BDA) (BDA = benzylidene acetone) leading to heterodinuclear NiFe and mononuclear Fe complexes related to the active sites of [NiFe]- and [Fe]-hydrogenases

While the parent Ni2 complex [Ni(RNPyS4)]2 (1a, R = H; RNPyS4 = 2,6-bis(2-mercaptophenylthiomethyl)-4-R-pyridine) cannot react with Fe(CO)3(BDA) in THF at room temperature, its substituted derivatives (1b, R = MeO; 1c, Cl; 1d, Br; 1e, i-Pr; 1f, BzO; 1g, MeS) have been found to react with Fe(CO)3(BDA) under the same conditions to give the first [RNPyS4] ligand-containing heterodinuclear [NiFe]-hydrogenase model complexes NiFe(RNPyS4)(CO)3 (2b, R = MeO; 2c, Cl; 2d, Br; 2e, i-Pr; 2f, BzO; 2g, MeS) along with the mononuclear [Fe]-hydrogenase model complexes Fe(RNPyS4)(CO) (3b, R = MeO; 3c, Cl; 3d, Br; 3e, i-Pr; 3f, BzO; 3g, MeS). However, when Ni2 complexes 1a–1g react with Fe(CO)3(BDA) in THF at the higher temperature of 40 °C, only the mononuclear complexes 3a–3g are obtained without the corresponding dinuclear complexes 2a–2g being isolated. While all the new complexes are characterized by elemental analysis and spectroscopy, the molecular structures of 1f, 2c, 3f and 3g have been further confirmed by X-ray crystallography. In addition, a possible pathway for the formation of 2a–2g and 3a–3g is suggested, which has been proved by monitoring the reaction course of dinuclear Ni2 complex 1e with Fe(CO)3(BDA) using in situ IR spectroscopy.

Iodine-catalyzed oxidative C–C bond cleavage for benzoic acids and benzamides from alkyl aryl ketones

Iodine-catalyzed, aerial oxygen supported C–C bond cleavage reaction of aryl alkyl ketones for the synthesis of benzoic acids and benzamides. Also benzylidene acetones and phenylacetylenes were converted to their aromatic acids at this conditions.

Xenorhabuds nematophila 세균 배양액 유래 미확인 생리활성 물질의 비티플러스 살충력 상승효과

`Bt-Plus` has been developed by mixing spores of Bacillus thuringiensis (Bt) and culture broth of Xenorhabdus nematophila (Xn). Despite its high toxicity, it has some imitation to broaden its efficacy against diverse insect pest spectrum. This study focuses on enhancement of Bt-Plus toxicity against semi-susceptible insect, Spodoptera exitgua, by addition of Xn metabolites. Two main Xn metabolites, oxindole (OI) and benzylideneacetone (BZA), are known to enhance the Bt insecticidal activities. The addition of OI or BZA significantly increased Bt-Plus pathogenicity. However, when the freeze-dried Xn culture broth was added to Bt-Plus, much less amount was enough to enhance the toxicity compared to the amount of OI or BZA. An HPLC analysis indicated that there were more than 12 unidentifed bacterial metabolites in Xn culture broth. These suggest that there are potent biological response modifiers in Xn metabolites other than OI and BZA.

High Speed Electrochemical Deposition Bath for Sn-Ag Alloy and Evaluation of Micro Solder Bump Plated on Ni-Coated Si Wafer

In flip chip packaging, especially high density interconnection, electrodeposition of Sn-Ag alloy has been attracted increasing attention from semiconductor industry as a replacement of toxic tin-lead solders. With aim of improving plating speed, life-time, and enhancing quality of micro solder bump, various electrochemical characteristics of strong acid electroplating bath composing of methane sulfonic acid (MSA), Ag-MSA, Sn-MSA, and several modification agents were investigated by using linear voltammetry techniques, cyclic voltammetric stripping (CVS) with controlled hydrodynamic condition with RDE. In addition, surface morphology, metallurgical structure and composition of Sn-Ag solder bump formed on Si wafer and deposition properties were characterized by using XRD, WDXRF, and SEM. The CVS measurements showed that suppressing the hydrogen evolution reaction at high cathodic current above 30mA/cm2 was critical, and small amount, less than 0.6 g/L, of benzylidene acetone was effective for this troublesome. The fundamental electrochemical responses revealed that the concentration of metallic complex ions, silver (I) and tin (II & IV), and its stability are crucial for better electroplating. In this study, the effects of complexing agent of thiourea, anti-oxidizer of hydroquinone, and several surfactants were also examined in terms of potential shift, current density, solution stability, and deposition rate. The results also showed that most electrochemical reactions in this bath composition are influenced by rotation speed, hence hydrodynamic conditions. With optimized bath solution, electroplating parameters, such as current efficiency, deposition rate, and elemental decay, and bath lifetime were also measured on micro-patterned Si wafer, and plating performance was compared with electrochemical properties. The optimized plating bath showed high deposition rate of 0.8μm/min/ASD, longer lifetime of 95 AH/L, proper eutectic alloy composition of 3.5 w/o and suitable for micro solder bump size of less than 20 μm. In this study, the relation of electrochemical and deposition characteristics with various additives and electrical properties of micro solder bumps will be discussed.

ChemInform Abstract: Rapid Access to α‐Carbolines via a One‐Pot Tandem Reaction of α,β‐Unsaturated Ketones with 2‐Nitrophenylacetonitrile and the anti‐Proliferative Activities of the Products.

AbstractA variety of α‐carbolines is readily prepared by reaction of 2‐nitrophenylacetonitrile with chromones (I) or benzylidene acetones (VI).

Digallane with redox-active diimine ligand: dualism of electron-transfer reactions.

The reactivity of digallane (dpp-Bian)Ga-Ga(dpp-Bian) (1), which consists of redox-active ligand 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-Bian), has been studied. The reaction of 1 with I2 proceeds via one-electron oxidation of each of two dpp-Bian ligands to a radical-anionic state and affords complex (dpp-Bian)IGa-GaI(dpp-Bian) (2). Dissolution of complex 2 in pyridine (Py) gives monomeric compound (dpp-Bian)GaI(Py) (3) as a result of a solvent-induced intramolecular electron transfer from the metal-metal bond to the dpp-Bian ligands. Treatment of compound 3 with B(C6F5)3 leads to removal of pyridine and restores compound 2. The reaction of compound 1 with 3,6-di-tert-butyl-ortho-benzoquinone (3,6-Q) proceeds with oxidation of all the redox-active centers in 1 (the Ga-Ga bond and two dpp-Bian dianions) and results in mononuclear catecholate (dpp-Bian)Ga(Cat) (4) (Cat = [3,6-Q](2-)). Treatment of 4 with AgBF4 gives a mixture of [(dpp-Bian)2Ag][BF4] (5) and (dpp-Bian)GaF(Cat) (6), which both consist of neutral dpp-Bian ligands. The reduction of benzylideneacetone (BA) with 1 generates the BA radical-anions, which dimerize, affording (dpp-Bian)Ga-(BA-BA)-Ga(dpp-Bian) (7). In this case the Ga-Ga bond remains unchanged. Within 10 min at 95 °C in solution compound 7 undergoes transformation to paramagnetic complex (dpp-Bian)Ga(BA-BA) (8) and metal-free compound C36H40N2 (9). The latter is a product of intramolecular addition of the C-H bond of one of the iPr groups to the C═N bond in dpp-Bian. Diamagnetic compounds 3, 5, 6, and 9 have been characterized by NMR spectroscopy, and paramagnetic complexes 2, 4, 7, and 8 by ESR spectroscopy. Molecular structures of 2-7 and 9 have been established by single-crystal X-ray analysis.

STRUCTURE OF N-HYDROXY-4-PHENYLBUT-3-EN-2-IMINE

Normal 0 The title compound, N-Hydroxy-4-phenylbut-3-en-2-imine[C 10 H 11 NO], was synthesized by reacting benzylidene acetone with hydroxylamine hydrochloride in the presence of base. The structure of the compound was characterized by single crystal XRD data. It crystallizes in the orthorhombic space group Pbc2 1 with unit-cell parameters: a= 5.591(6)A, b=22.019(3)A, c = 14.742(2) A, β = 90.0o, Z = 4. The crystal structure has been elucidated by Direct methods and refined to a final R -value of 0.056 for 1535 observed reflections. In the crystal molecules are linked by two N-H...N intermolecular h -bonds forming dimer. Molecules in the unit cell are packed together to form well defined layers.

Electrochemical reduction and consumption of 4-phenyl-3-buten-2-one

When benzylideneacetone (BDA), a commonly used brightener in the zinc plating process, is added to a solution containing Zn2+ ions in aqueous 0.5M KCl and 0.1M H3BO3, the zinc electroreduction potential shifts towards negative values by about 0.24V to -1.28V vs. SCE. Two stages are observed during the reduction of Zn2+ to zinc at -1.28V in the presence of BDA. Besides Zn2+ reduction, the BDA, itself, is reduced in two steps at the mercury electrode. The BDA is reduced at a potential of -1.12V versus saturated calomel electrode (SCE) for the first step, the formation of 4-phenyl-2-butanone and at -1.32V vs. SCE for the second step, the formation of 4-phenyl-2-butanol. It was found that, Zn2+ ions do not form complexes with BDA in the substrate's concentrations used in the present study. The mineralization of the solution, which is the loss of organic compounds from solution, occurs during BDA electrolysis and is due to the rapid decomposition of BDA. The mineralization obtained after 60minutes with current density of 0.015 A per square centimeter results in 16% loss of carbon content.

AN ENTOMOPATHOGENIC BACTERIUM, Xenorhabdus nematophila, SUPPRESSES EXPRESSION OF ANTIMICROBIAL PEPTIDES CONTROLLED BY TOLL AND IMD PATHWAYS BY BLOCKING EICOSANOID BIOSYNTHESIS

Immune-associated genes of the beet armyworm, Spodoptera exigua, were predicted from 454 pyrosequencing transcripts of hemocytes collected from fifth instar larvae challenged with bacteria. Out of 22,551 contigs and singletons, 36% of the transcripts had at least one significant hit (E-value cutoff of 1e-20) and used to predict immune-associated genes implicated in pattern recognition, prophenoloxidase activation, intracellular signaling, and antimicrobial peptides (AMPs). Immune signaling and AMP genes were further confirmed in their expression patterns in response to different types of microbial challenge. To discriminate the AMP expression signaling between Toll and Imd pathways, RNA interference was applied to specifically knockdown each signal pathway; the separate silencing treatments resulted in differential suppression of AMP genes. An entomopathogenic bacterium, Xenorhabdus nematophila, suppressed expression of most AMP genes controlled by Toll and Imd pathways, while challenge with heat-killed X. nematophila induced expression of all AMPs in experimental larvae. Benzylideneacetone (BZA), a metabolite of X. nematophila, suppressed the AMP gene inductions when it was co-injected with the heat-killed X. nematophila. However, arachidonic acid, a catalytic product of PLA2 , significantly reversed the inhibitory effect of BZA on the AMP gene expression. This study suggests that X. nematophila suppresses AMP production controlled by Toll and Imd pathways by inhibiting eicosanoid biosynthesis in S. exigua.