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PubMed2005

An increased receptive field of olfactory receptor Or43a in the antennal lobe of Drosophila reduces benzaldehyde-driven avoidance behavior.

Most animals orient themselves in their environment through the perception of olfactory cues. In order to gain insight into the principles of olfactory processing in Drosophila, we misexpressed olfactory receptor Or43a in additional olfactory receptor neurons of the third antennal segment using enhancer trap line GH320. The behavioral response of GH320/UAS-or43a flies was changed upon benzaldehyde application. Using the T-maze assay, misexpressing flies performed a reduced avoidance reaction to benzaldehyde as compared with wild type. This reduction of avoidance could be mimicked in wild type flies by exposing them to a mixture of benzaldehyde and ethyl acetate. We therefore conclude that the application of benzaldehyde, an identified ligand of Or43a, resulted in activation of a number of glomeruli in transformed flies in addition to glomerulus DA4, which is the regular target of Or43a expressing neurons. Our results demonstrate the relevance of specific olfactory sensory input and subsequent processing in the antennal lobe for Drosophila behavior.

Animals↗

PubMed1989

Benzaldehyde lyase, a novel thiamine PPi-requiring enzyme, from Pseudomonas fluorescens biovar I.

Pseudomonas fluorescens biovar I can grow on benzoin as the sole carbon and energy source. This ability is due to benzaldehyde lyase, a new type of enzyme that irreversibly cleaves the acyloin linkage of benzoin, producing two molecules of benzaldehyde. Benzaldehyde lyase was purified 70-fold and found to require catalytic amounts of thiamine PPi (TPP) and a divalent cation as cofactors. Optimal activity was obtained with a 1.0 mM concentration of Mn2+, Mg2+, or Ca2+. Gel permeation chromatography indicated a native molecular weight of 80,000, whereas the enzyme migrated in sodium dodecyl sulfate-containing polyacrylamide gels as a single polypeptide with a molecular weight of 53,000. Benzaldehyde lyase is highly specific; of a variety of structurally related compounds tested, only benzoin and anisoin (4,4'-dimethoxybenzoin) acted as substrates, their apparent Kms being 9.0 x 10(-3) and 3.25 x 10(-2) mM, respectively. A catalytic mechanism for the enzyme is proposed.

Aldehyde-Lyases↗

PubMed1999

Enhanced benzaldehyde formation by a monokaryotic strain of Pycnoporus cinnabarinus using a selective solid adsorbent in the culture medium.

A monokaryotic strain of the white-rot fungus Pycnoporus cinnabarinus was shown to produce, in a 2-L bioreactor culture, 100 mg.L-1 benzaldehyde (bitter almond aroma) from L-phenylalanine with a productivity of 33 mg.L-1.day-1. The addition of HP20 resin, a styrene divinylbenzene copolymer highly selective for benzaldehyde, enabled an eightfold increase in the production of benzaldehyde and a twofold increase in productivity. In the presence of HP20 resin, the production of 790 mg.L-1 benzaldehyde was concomitant with the synthesis of cinnamic acid derivatives of high organoleptic notes such as cinnamaldehyde, cinnamyl alcohol, and methyl cinnamate.

Adsorption↗

PubMed1981

Effect of benzaldehyde on the proliferation of HeLa cells.

The effect of benzaldehyde on the proliferation of HeLa cells was studied in the present work. Benzaldehyde caused a dose-dependent reduction of the proliferation of HeLa cells in vitro. This effect of benzaldehyde might be caused principally by a reversible and mild growth modulation, since no serious morphological damage was observed. Delay of the S and G2 periods in the cell cycle upon addition of benzaldehyde was observed by the pulse-labeling technique using 3H-thymidine.

Benzaldehydes↗

PubMed2003

Effect of alkyl group size on the mechanism of acid hydrolyses of benzaldehyde acetals.

Hydrolyses of benzaldehyde acetals, PhCH(OR)(2), are specific hydrogen-ion catalyzed when R = methyl, n-butyl, but with secondary and tertiary alkyl derivatives, R = i-propyl, s-butyl, t-butyl, t-amyl, hydrolyses are general-acid catalyzed. The Brønsted alpha values for both secondary and tertiary alkyl groups are in the range: alpha = 0.57-0.61. A simple iterative procedure was developed to estimate the individual rate constants for general-acid catalysis by the diacid and monoacid forms of succinic acid buffer. Plots of log k(obs) (at [buffer] = 0 M) against pH are linear for the secondary and tertiary acetals, and plots of log k(H) for the H(3)O(+)-catalyzed reaction, (13)C and (1)H chemical shifts, and (1)J(CH) coupling constants against the Charton steric parameter, nu, for alkoxy groups are linear. The second-order rate constant, k(H), increases about 100-fold on going from R = Me to R = t-amyl, indicating the significant role of steric effects on reactivity. Steric effects upon (13)C NMR chemical shifts and coupling constants indicate that increasing the bulk of the alkoxy moiety increases the electron density at the carbon reaction center, which accelerates hydrolysis. Analysis of the Jencks-More-O'Ferrall free energy diagram for the reaction provides support for concerted proton transfer and C-O bond breaking in the transition state for hydrolyses of benzaldehyde acetals with secondary and tertiary alkyl groups in contrast to specific hydrogen catalysis with R = Me and n-Bu. All our results are consistent with rate-determining acid hydrolysis of benzaldehyde dialkyl acetals to hemiacetal intermediates that breakdown rapidly to benzaldehyde.

Journal Article↗

PubMed2004

The microwave and infrared spectroscopy of benzaldehyde: conflict between theory and experimental deductions.

Recently, it has been proposed that ab initio calculations cannot accurately treat molecules comprised of a benzene ring with a pi-conjugated substituent, for example, benzaldehyde. Theoretical predictions of the benzaldehyde barrier to internal rotation are typically a factor of 2 too high in comparison to the experimental values of 4.67 (infared) and 4.90 (microwave) kcal mol(-1). However, both experiments use Pitzer's 1946 model to compute the reduced moment of inertia and employ the experimentally observed torsional frequency to deduce benzaldehyde's rotational barrier. When Pitzer's model is applied to a system with a nonconjugated functional group, such as phenol, the model and theoretical values are in close agreement. Therefore, we conclude the model may not account for conjugation between the substituent and the pi-system of benzene. The experimental values of the benzaldehyde rotational barrier are therefore misleading. The true rotational barrier lies closer to the theoretically extrapolated limit of 7.7 kcal mol(-1), based on coupled cluster theory.

Journal Article↗

PubMed2005

Selective attachment of benzaldehyde on Si(100)-2 x 1: structure, selectivity, and mechanism.

The interaction of benzaldehyde with the Si(100) surface has been investigated as a model system for understanding the interaction of conjugated pi-electron systems with semiconductor surfaces. Vibrational features of chemisorbed benzaldehyde unambiguously demonstrate that the carbonyl group directly interacts with the Si surface dangling bonds, evidenced in the disappearance of the C=O stretching mode around 1713 cm(-1) coupled with the retention of all vibrational signatures of its phenyl ring. X-ray photoemission spectroscopy shows that both C 1s and O 1s binding energies of the carbonyl group display large downshifts by 1.9 and 1.3 eV, respectively. Vibrational and electronic results show that the covalent attachment of benzaldehyde on Si(100) occurs in a highly selective manner through the direct interaction of both C and O atoms of the carbonyl group with a Si=Si dimer to form a four-membered Si-C-O-Si ring at the interface, leaving a nearly unperturbed phenyl ring protruding into vacuum. This conclusion is further confirmed by the observation of a predominant protrusion for benzaldehyde adsorbed on Si(100)-2 x 1 in scanning tunneling microscopy experiments, consistent with the predication of density-functional theory calculation.

Journal Article↗

PubMed1991

Kinetics of induction of cytosolic benzaldehyde: NADP and propionaldehyde: NAD aldehyde dehydrogenase activities in rat livers from male Wistar rats.

The time courses of induction of liver cytosolic aldehyde dehydrogenases using benzaldehyde and propionaldehyde as substrates and NADP and NAD as co-factors after i.p. and intragastric (i.g.) administration of 2-acetylaminofluorene (2-AAF), 20-methylcholanthrene (20-MC), beta-naphthoflavone (beta-NF) and benzo[alpha]pyrene (B[alpha]P) were investigated in male Wistar rats. 2-AAF did not induce the aldehyde dehydrogenase activities with any substrate:co-factor combination. The other three inducers all induced the oxidation of the aldehydes in a reversible manner. With an i.p. route of administration (one daily dose for four consecutive days) (20-MC) was the most potent inducer giving a 240-fold increase of benzaldehyde: NADP activity on the ninth day. beta-NF elevated the activity 20-fold with peak activity at day 7, while B[alpha]P gave maximal induction on day 5 with a 60-fold increase in activity over the corresponding value for normal liver. The i.g. administration resulted in a weaker but coordinated induction of activity with peak activity on the sixth day for the different inducers. The activity ratio benzaldehyde:NADP/propionaldehyde:NAD, 0.78 in normal rats, was altered in all induced states to a level close to 4. The interpretation of our work supports the hypothesis that the inducers in this respect use the same mechanisms of induction. The differences noted can be explained by variations in the exposure of the liver to the administered dose and/or by differences in receptor affinity. The inducibility of benzaldehyde:NADP aldehyde dehydrogenase in rat liver exceeds by orders of magnitude the ability of the same inducers to increase the amount of the activity of other drug metabolizing enzymes such as glutathione S-transferase, cytochrome P450 and cytochrome b5. The reversible, drug-dependent induction characterized in normal rat liver in this work differs entirely from the persistent constitutive elevation of the same enzymes in preneoplastic liver nodules.

2-Acetylaminofluorene↗

PubMed1983

Encephalopathy in rats and nephropathy in rats and mice after subchronic oral exposure to benzaldehyde.

Male and female Fischer 344 rats and B6C3F1 mice were treated daily (5 days/wk) with benzaldehyde by gavage either in 12 doses of 0 (vehicle control), 100 (rats only), 200, 400, 800, 1600 or (for mice only) 3200 mg/kg body weight/day (followed by 2 days' observation without treatment), or for 90 days in doses of 0, 50, 100, 200, 400 or 800 mg/kg/day (rats) or 0, 75, 150, 300, 600 or 1200 mg/kg/day (mice). In the acute studies, benzaldehyde induced deaths and decreased body-weight gain in both sexes of rats given 800 or 1600 mg/kg/day and caused deaths in both sexes of mice given 1600 or 3200 mg/kg/day. In the 90-day studies, deaths occurred in both sexes of rats on 800 mg/kg/day and in male mice on 1200 mg/kg/day. Body-weight gain was depressed in male rats on 800 mg/kg/day, in male mice on 600 mg/kg/day and in female mice on 1200 mg/kg/day. Necrotic and degenerative lesions were seen in the cerebellar and hippocampal regions of the brain in both sexes of rats given 800 mg/kg/day, but not in mice. Renal tubular necrosis occurred in male and female rats on 800 mg/kg/day and in male mice on 1200 mg/kg/day. Mild epithelial hyperplasia or hyperkeratosis of the forestomach was seen in male and female rats on 800 mg/kg/day. In this limited study, the no-observed-toxic-effect doses of benzaldehyde administered by gavage were 400 mg/kg/day in male and female rats, 300 mg/kg/day in male mice and 600-1200 mg/kg/day in female mice.

Administration, Oral↗

PubMed1989

Modulation of cis-dichlorodiammineplatinum(II)-induced cytotoxicity by benzaldehyde derivatives.

The cell inactivating effect of cis-dichlorodiammineplatinum(II) in combination with 2-substituted benzaldehyde derivatives was tested using cultured human NHIK 3025 cells. Simultaneous drug combination with benzaldehyde protected cells from cis-DDP-induced cell inactivation in a dose-dependent manner. Substitution with electron-releasing groups, i.e. -CH3 and -OH, adjacent to the aldehyde moiety increased the protective effect relative to benzaldehyde. Electron-withdrawing, or bulky, substituents reduced the protective effect. Protection from cell inactivation by cis-DDP coincided with an aldehyde-mediated reduction in platinum accumulation.

Benzaldehydes↗

PubMed2005

Exploring the active site of benzaldehyde lyase by modeling and mutagenesis.

Benzaldehyde lyase (BAL) is a thiamin diphosphate-dependent enzyme, which catalyzes the breakdown of (R)-benzoin to benzaldehyde. In essence, this is the reverse of the carboligation reaction catalyzed by benzoylformate decarboxylase (BFD). Here, we describe the first steps towards understanding the factors influencing BFD to form a CC bond under conditions wherein BAL will cleave the same bond. What are the similarities and differences between these two enzymes that result in the different catalytic activities? The X-ray structures of BFD and pyruvate decarboxylase (PDC) were used as templates for modeling benzaldehyde lyase. The model shows that a glutamine residue, Gln113, replaces the active site histidines of BFD and PDC. Replacement of the Gln113 by alanine or histidine reduced the value of k(cat) for lyase activity by more than 200-fold. The residues in BFD interacting with the phenyl ring of benzoylformate have similarly positioned counterparts in BAL but Ser26, the residue known to interact with the carboxylate group of benzoylformate, has been replaced by an alanine (Ala28). The BAL A28S variant exhibited 7% of WT activity in the BAL assay but, in the most intriguing result, this variant was able to catalyze the decarboxylation of benzoylformate. Conversely, the BFD S26A variant was unable to cleave benzoin.

Aldehyde-Lyases↗

PubMed2004

Concerning the stability of benzyl alcohol: formation of benzaldehyde dibenzyl acetal under aerobic conditions.

An impurity in benzyl alcohol was identified as benzaldehyde dibenzyl acetal (BDBA). The component BDBA is reversibly formed by the reaction of benzyl alcohol with benzaldehyde, an oxidative degradation product of benzyl alcohol. Whereas, BDBA is a known chemical entity, it is not typically controlled in commercial benzyl alcohol since it cannot be formed in the absence of benzaldehyde, which is itself generally controlled. However, once commercial benzyl alcohol is exposed to the atmosphere, formation of BDBA is possible. The synthesis and characterization of BDBA is reported. The ability of BDBA to react with alcohols to form other types of acetals, and the impact of low levels of BDBA on the quantitative analysis of pharmaceutical products, are considered.

Acetals↗

PubMed2005

Development and validation of an HPLC-UV method for the analysis of methoxyamine using 4-(diethylamino)benzaldehyde as a derivatizing agent.

Methoxyamine (MX) is a potential new anti-cancer drug. In this paper, a quantitative HPLC-UV method for MX using 4-(diethylamino)benzaldehyde (DEAB) as a derivatizing agent has been developed and validated. The studies showed that MX reacts with DEAB under acidic conditions to form protonated 4-(diethylamino)benzaldehyde o-methyloxime (DBMOH+). The equilibrium between DBMOH+ and its conjugate base 4-(diethylamino)benzaldehyde o-methyloxime (DBMO) is affected by both buffer concentration and organic solvent content in the solution. The method developed uses a reversed phase C18 column for the separation of MX derivatives, an internal standard benzil for method calibration, and a UV detector at a wavelength of 310 nm for analyte detection. The MX derivatives can be resolved in ca. 20 min. The method has a linear calibration range from 0.100 to 10.0 microM with a correlation coefficient of 0.999 for MX and a detection limit of 5 pmol with a 50 microl sample size. The intra-assay and inter-assay precision expressed in terms of percent relative standard deviation were < or =5 and 8%; and the intra-assay and inter-assay accuracy defined as the measured value divided by the accepted value multiplied by 100% were 94.2-100 and 92.6-111%, respectively. This method may be used for the analysis of MX in pharmaceutical preparations.

Acetic Acid↗

PubMed2006

Time-dependent conversion of benzyl alcohol to benzaldehyde and benzoic acid in aqueous solutions.

The oxidative reaction: benzyl alcohol-benzaldehyde-benzoic acid was investigated in time in aqueous solutions of benzyl alcohol widely used as a preservative in medicine and cosmetology. The solutions of benzyl alcohol were stored at concentrations from 0.005 to 2.09 mg/ml for a long time under different conditions. The presence of benzaldehyde and benzoic acid in these solutions was controlled by liquid chromatography on silica sorbent in water. The content of benzoic acid and potentially toxic benzaldehyde in solutions depending on the initial concentration of benzyl alcohol, on time, and on storage conditions was evaluated quantitatively.

Anesthetics, Local↗

PubMed2001

Prediction of partition coefficient and toxicity for benzaldehyde compounds by their capacity factors and various molecular descriptors.

The log Kow and log Sw values of 14 substituted benzaldehyde compounds were determined by the shake-flask method. Acute toxicities of 14 substituted benzaldehyde compounds to Daphnia magna were recorded. Their capacity factors (k') were determined by reversed phased high-performance liquid chromatography (RP-HPLC) on C18 column and methanol-water eluent. Molecular connectivity indices, the linear solvation energy relationships (LSER) parameters, and quantum chemical parameters were calculated for the tested chemicals and used to develop quantitative structure-retention relationship (QSRR) and quantitative structure-property/activity relationship (QSPR/QSAR). Results demonstrated that the molecular connectivity indices, LSER parameters, and quantum chemical parameters could be used to predict the k' for compounds studied, LSER method was more accurate. The results also show that chromatographic retention data, log k', can be used to predict log Kow and log Sw for tested compounds. The log k'w can be directly utilized as hydrophobic descriptors to predict the toxicity to D. Magna for benzaldehyde compounds.

Benzaldehydes↗

PubMed2006

Experimental and theoretical studies on the hydrogen-bond-promoted enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with benzaldehyde.

The enantioselective hetero-Diels-Alder (HDA) reaction of Danishefsky's diene with benzaldehyde has been achieved catalytically by a series of alpha,alpha,alpha',alpha'-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL) derivatives through hydrogen-bonding activation, affording 2-phenyl-2,3-dihydro-4H-pyran-4-one after trifluoroacetic acid workup in moderate yield and good enantioselectivity. The alpha,alpha'-aryl substituents in the TADDOL molecules are found to exert a significant impact on both the activity and the enantioselectivity of the catalysis. In combination with the experimental investigations, the mechanism of the present reaction has also been studied theoretically using the ONIOM (B3LYP/6-31G:PM3) method with trans-1,3-dimethoxy-1,3-butadiene as the model for Danishefsky's diene. In agreement with the experimental findings, the calculation results indicate that this TADDOL-catalyzed HDA reaction proceeds via a concerted mechanism through an asynchronous and zwitterionic transition structure (TS). The carbonyl group of benzaldehyde is activated by forming an intermolecular hydrogen bond with one of the hydroxy groups of TADDOL. Meanwhile, the intramolecular hydrogen bond between the two hydroxy groups in TADDOL is found to facilitate the intermolecular hydrogen bonding with benzaldehyde. The sense of asymmetric induction is well-rationalized by the analysis of the relative energies of TADDOL-complexed TSs, while the different stereocontrol capabilities exhibited by TADDOLs in the reaction can be qualitatively established on the basis of the structural features of their corresponding TSs.

Alkenes↗

PubMed2006

Chaetopyranin, a benzaldehyde derivative, and other related metabolites from Chaetomium globosum, an endophytic fungus derived from the marine red alga Polysiphonia urceolata.

Cultivation of the endophytic fungus Chaetomium globosum, which was isolated from the inner tissue of the marine red alga Polysiphonia urceolata, resulted in the isolation of chaetopyranin (1), a new benzaldehyde secondary metabolite. Ten known compounds were also isolated, including two benzaldehyde congeners, 2-(2',3-epoxy-1',3'-heptadienyl)-6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (2) and isotetrahydroauroglaucin (3), two anthraquinone derivatives, erythroglaucin (4) and parietin (5), five asperentin derivatives including asperentin (6, also known as cladosporin), 5'-hydroxy-asperentin-8-methylether (7), asperentin-8-methyl ether (8), 4'-hydroxyasperentin (9), and 5'-hydroxyasperentin (10), and the prenylated diketopiperazine congener neoechinulin A (11). The structures of these compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as low- and high-resolution mass experiments). To our knowledge, compound 1 represents the first example of a 2H-benzopyran derivative of marine algal-derived fungi as well as of the fungal genus Chaetomium. Each isolate was tested for its DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging property. Compounds 1-4 were found to have moderate activity. Chaetopyranin (1) also exhibited moderate to weak cytotoxic activity toward several tumor cell lines.

Animals↗

PubMed2003

More potent inhibition of human CYP2A6 than mouse CYP2A5 enzyme activities by derivatives of phenylethylamine and benzaldehyde.

1. A rapid 96-well plate assay method was developed and validated to measure liver microsomal coumarin 7-hydroxylation in vitro. 2. The method was used to test inhibition of human and mouse CYP2A enzymes by three phenylethylamine derivatives 2-(p-tolyl)-ethylamine, amphetamine, 2-phenylethylamine and benzaldehyde, and two of its derivatives, 4-methylbenzaldehyde and 4-methoxybenzaldehyde. 3. The benzaldehyde derivatives were more potent inhibitors of CYP2A5 than the phenylethylamines. The K(ic) value of 4-methylbenzaldehyde was 3.4 micro M and for 4-methoxybenzaldehyde it was 0.86 micro M for CYP2A5. 4. Amphetamine is a weak inhibitor of CYP2A6, whereas benzaldehyde is a suicide inhibitor with K(inact) = 0.16 min(-1) and K(I) = 18 micro M. The K(ic) values of 2-phenylethylamine, 2-(p-tolyl)-ethylamine, 4-methylbenzaldehyde and 4-methoxybenzaldehyde were 1.13, 0.23, 0.36 and 0.73 micro M for CYP2A6, respectively. 5. Novel potent inhibitors were found for CYP2A6 and, except for 4-methoxybenzaldehyde, all the compounds inhibited CYP2A5 and CYP2A6 enzymes differentially. These data add to the refinement of CYP2A enzyme active sites and provide chemical leads for developing novel chemical inhibitors of the CYP2A6 enzyme.

Animals↗