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PubMed1986

Phenobarbital enhances the aldehyde dehydrogenase activity of rat hepatocytes in vitro and in vivo.

Aldehyde dehydrogenase (ALDH) was measured in primary cultures of hepatocytes obtained with collagenase perfusion from livers of Long-Evans rats. After seven days in culture, basal ALDH activity, protein content and DNA content are significantly decreased. Exposure of the cultures to phenobarbital (PB, 3 mM in the media) does not prevent the decrease of DNA content, although it keeps protein at relatively higher levels. The activity of ALDH is not only preserved, but also significantly enhanced, when propionaldehyde, phenylacetaldehyde, benzaldehyde and D-glucuronolactone are used as substrates and NAD as the coenzyme. A relative increase of activity is also noted when ALDH is measured with benzaldehyde and NADP. Treatment of Long-Evans animals with PB (1 mg/ml, in drinking water for 2 weeks) leads to similar relative increases of the ALDH activity. In absolute values, however, enzyme activities found after in vivo treatment with PB are higher, compared to those obtained after in vitro exposure. These results show that ALDH activity can be greatly enhanced by PB in primary hepatocyte cultures, free from any indirect endogenous influences.

Aldehyde Dehydrogenase↗
PubMed1978

The effect of microcapsule size on the oxidative decomposition of core material.

The factors that affect the size of microcapsules and the oxidation of their benzaldehyde core have been examined. The pH of the preparation changed the overall size of the microcapsules which reached a maximum diameter at pH 4.1. The size of the core droplets also varied with the preparative pH and their oxidation rate depended on the bulk droplet size rather than their surface area. A rapid oxidation of benzaldehyde associated with the microcapsule wall resulted in a preliminary peak in the oxidation curve. Explanations for these phenomena are discussed.

Capsules↗
PubMed2005

Involvement of molybdenum hydroxylases in reductive metabolism of nitro polycyclic aromatic hydrocarbons in mammalian skin.

Molybdenum hydroxylases, aldehyde oxidase and xanthine oxidoreductase, were shown to be involved in the nitroreduction of 2-nitrofluorene (NF), 1-nitropyrene, and 4-nitrobiphenyl, environmental pollutants, in the skin of various mammalian species. NF was reduced to 2-aminofluorene by hamster skin cytosol in the presence of 2-hydroxypyrimidine, 4-hydroxypyrimidine, N(1)-methylnicotinamide, or benzaldehyde, but not hypoxanthine or xanthine. Inhibitors of aldehyde oxidase markedly inhibited these nitroreductase activities, but oxypurinol, an inhibitor of xanthine oxidoreductase, had little effect. In DEAE column chromatography of hamster skin cytosol, the major fraction exhibiting nitroreductase activity also showed aldehyde oxidase activity. 2-Hydroxypyrimidine-linked nitroreductase activities of skin cytosol from rabbits and guinea pigs were also inhibited by an inhibitor of aldehyde oxidase. In contrast, nitroreductase activities of skin cytosols of rats and mice were markedly inhibited by oxypurinol. When aldehyde oxidase activity was estimated in skin cytosol of various mammals using benzaldehyde oxidase activity as a marker, considerable variability of the activity was found. The highest activity was observed with hamsters, and the lowest activity with rats. On the other hand, the highest xanthine oxidoreductase activity was observed with rats, and the lowest activity with rabbits. These skin cytosols of various mammals also exhibited significant 2-hydroxypyrimidine-linked nitroreductase activities toward 1-nitropyrene and 4-nitrobiphenyl catalyzed by aldehyde oxidase and xanthine oxidoreductase. Thus, NF was mainly reduced by aldehyde oxidase and xanthine oxidoreductase in skins of animals. However, the contributions of these two molybdenum hydroxylases were considerably different among animal species.

Aldehyde Oxidase↗
PubMed2006

Mechanism for covalent binding of rofecoxib to elastin of rat aorta.

We have previously reported that oral administration of [(14)C]rofecoxib to rats resulted in the long retention of radioactivity by the aorta as a consequence of covalent binding to elastin. Treatment of rats with alpha-phenyl-alpha-propylbenzeneacetic acid 2-[diethylamino]-ethyl ester hydrochloride (SKF-525A), a cytochrome P450 inhibitor, significantly decreased the systemic exposure of 5-hydroxyrofecoxib, one of the main metabolites of rofecoxib, whereas there was no statistically significant change in the retention of radioactivity from [(14)C]rofecoxib in the aorta. On the other hand, the aortic retention of radioactivity closely correlated to the systemic exposure of unchanged rofecoxib in the dose range between 2 and 10 mg/kg. A covalent binding study of [(14)C]rofecoxib in vitro using rat aorta homogenate in the presence of d-penicillamine, hydralazine, beta-aminopropionitrile, and sodium borohydride suggested that the aldehyde group of allysine in elastin was relevant to the covalent binding. In a model reaction using benzaldehyde, rofecoxib but not 5-hydroxyrofecoxib reacted with the aldehyde group of benzaldehyde in a manner of condensation reaction under a physiological pH condition. A histopathological examination using an electron microscope demonstrated that multiple oral administration of rofecoxib to rats caused marked degradation of the elastic fiber system of the aorta. These results suggested that rofecoxib as such is reactive in vivo, undergoing a condensation reaction with allysine, thereby preventing the formation of cross-linkages in elastin, i.e., desmosine and isodesmosine, and causing the degradation of the elastic fibers.

Animals↗
PubMed1980

Evidence for isofunctional enzymes used in m-cresol and 2,5-xylenol degradation via the gentisate pathway in Pseudomonas alcaligenes.

Study of the reaction sequence by which Pseudomonas alcaligenes (P25X1) and derived mutants degrade m-cresol, 2,5-xylenol, and their catabolites has provided indirect evidence for the existence of two or more isofunctional enzymes at three different steps. Maleylpyruvate hydrolase activity appears to reside in two different proteins with different specificity ranges, one of which (MPH1) is expressed constitutively; the other (MPH11) is strictly inducible. Two gentisate 1,2-dioxygenase activities were found, one of which is constitutively expressed and possesses a broader specificity range than the other, which is inducible. From oxidation studies with intact cells, there appear to be two activities responsible for the 6-hydroxylation of 3-hydroxybenzoate, and again a broadly specific activity is present regardless of growth conditions; the other is inducible by 3-hydroxybenzoate. Three other enzyme activities are also detected in uninduced cells, viz., xylenol methylhydroxylase, benzylalcohol dehydrogenase, and benzaldehyde dehydrogenase. All apparently possess broad specificity. Fumarylpyruvate hydrolase was also detected but only in cells grown with m-cresol, 3-hydroxybenzoate, or gentisate. Mutants, derived either spontaneously or after treatment with mitomycin C, are described, certain of which have lost the ability to grow with m-cresol and 2,5-xylenol and some of which have also lost the ability to form the constitutive xylenol methylhydroxylase, benzylalcohol dehydrogenase, benzaldehyde dehydrogenase, 3-hydroxybenzoate 6-hydroxylase, and gentisate 1,2-dioxygenase. Such mutants, however, retain ability to synthesize inducibly a second 3-hydroxybenzoate 6-hydroxylase and gentisate 1,2-dioxygenase, as well as maleylpyruvate hydrolase (MPH11) and fumarylpyruvate hydrolase; MPH1 was still synthesized. These findings suggest the presence of a plasmid for 2,5-xylenol degradation which codes for synthesis of early degradative enzymes. Other enzymes, such as the second 3-hydroxybenzoate 6-hydroxylase, gentisate 1,2-dioxygenase, maleylpyruvate hydrolase (MPH1 and MPH11), and fumarylpyruvate hydrolase, appear to be chromosomally encoded and, with the exception of MPH1, strictly inducible.

Alcohol Oxidoreductases↗
PubMed1984

Initial reactions involved in the dissimilation of mandelate by Rhodotorula graminis.

Rhodotorula graminis utilized DL-mandelate, L(+)-mandelate, and D(-)-mandelate as sole sources of carbon and energy. Growth on these aromatic substrates resulted in the induction of an NAD-dependent D(-)-mandelate dehydrogenase and a dye-linked L(+)-mandelate dehydrogenase, each catalyzing the stereospecific conversion of its respective enantiomer of mandelate to benzoylformate. Benzoylformate was oxidized to benzaldehyde, which was dehydrogenated to benzoate by an NAD-dependent benzaldehyde dehydrogenase. Benzoate was further metabolized through p-hydroxybenzoate and the protocatechuate branch of the beta-ketoadipate pathway.

Alcohol Oxidoreductases↗
PubMed1989

Regulator and enzyme specificities of the TOL plasmid-encoded upper pathway for degradation of aromatic hydrocarbons and expansion of the substrate range of the pathway.

The TOL plasmid upper pathway operon encodes enzymes involved in the catabolism of aromatic hydrocarbons such as toluene and xylenes. The regulator of the gene pathway, the XylR protein, exhibits a very broad effector specificity, being able to recognize as effectors not only pathway substrates but also a wide variety of mono- and disubstituted methyl-, ethyl-, and chlorotoluenes, benzyl alcohols, and p-chlorobenzaldehyde. Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase, two upper pathway enzymes, exhibit very broad substrate specificities and transform unsubstituted substrates and m- and p-methyl-, m- and p-ethyl-, and m- and p-chloro-substituted benzyl alcohols and benzaldehydes, respectively, at a high rate. In contrast, toluene oxidase only oxidizes toluene, m- and p-xylene, m-ethyltoluene, and 1,2,4-trimethylbenzene [corrected], also at a high rate. A biological test showed that toluene oxidase attacks m- and p-chlorotoluene, albeit at a low rate. No evidence for the transformation of p-ethyltoluene by toluene oxidase has been found. Hence, toluene oxidase acts as the bottleneck step for the catabolism of p-ethyl- and m- and p-chlorotoluene through the TOL upper pathway. A mutant toluene oxidase able to transform p-ethyltoluene was isolated, and a mutant strain capable of fully degrading p-ethyltoluene was constructed with a modified TOL plasmid meta-cleavage pathway able to mineralize p-ethylbenzoate. By transfer of a TOL plasmid into Pseudomonas sp. strain B13, a clone able to slowly degrade m-chlorotoluene was also obtained.

Enzyme Induction↗
PubMed1997

mucK, a gene in Acinetobacter calcoaceticus ADP1 (BD413), encodes the ability to grow on exogenous cis,cis-muconate as the sole carbon source.

Benzyl alcohol, benzaldehyde, benzoate, and anthranilate are metabolized via catechol, cis,cis-muconate, and the beta-ketoadipate pathway in Acinetobacter calcoaceticus ADP1 (BD413). Mutant strain ISA25 with a deletion spanning catBCIJF and unable to metabolize muconate further will not grow in the presence of an aromatic precursor of muconate. Growth on fumarate as the sole carbon source with added benzyl alcohol or benzaldehyde selected spontaneous mutants of ISA25. After repair of the cat deletion by natural transformation with linearized plasmid pPAN4 (catBCIJF) 10 mutants were unable to grow on benzoate of cis,cis-muconate but could still grow on anthranilate. Transformation with wild-type chromosomal DNA demonstrated the presence of two unlinked mutations in each strain, one in the benABCD region, encoding the conversion of benzoate to catechol, and the other in a gene determining the ability to grow on exogenous cis,cis-muconate. The wild-type gene, named mucK, was cloned into pUC18, and its nucleotide sequence was determined. It encodes a 413-residue protein of M(r) = 45,252 which is a member of a superfamily of membrane transport proteins and which is within a subgroup involved in the uptake of organic acids. Five of the mutant alleles were cloned, and the mutations were determined by nucleotide sequencing. All the mutations were in the mucK coding region and consisted of three deletions, one duplication, and a substitution. Insertional inactivation of mucK resulted in the loss of the ability to utilize exogenous muconate. The location of mucK on the chromosome appeared to be unique for genes associated with the benzoate branch of the beta-ketoadipate pathway in being close to the pca-qui-pob gene cluster (for p-hydroxybenzoate utilization) and distant from the functionally related ben-cat cluster. Downstream of mucK and transcribed in the same direction is an open reading frame encoding a protein of 570 residues (M(r) = 63,002) which shows considerable homology with a mammalian electron transport protein; its insertional inactivation had no detectable phenotypic effect.

Acinetobacter calcoaceticus↗
PubMed1999

Purification and some properties of hamster liver aldehyde oxidase.

Aldehyde oxidase was purified from hamster liver cytosol by ammonium sulfate fractionation, chromatography on DEAE-cellulose and Phenyl-Toyopearl, and HPLC-gel filtration on TSK-gel G3000SW(XL) column. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Its molecular weight was determined to be 144800 by SDS-PAGE and 288000 by HPLC gel filtration. The isoelectric point was pH 5.1. The apparent Km and Vmax for benzaldehyde and 2-hydroxypyrimidine were 19.0 and 4.4 microM, and 165 and 211 nmol/min/mg protein, respectively. The benzaldehyde oxidase activity was markedly inhibited by menadione and chlorpromazine. The substrate specificity was different from those of the enzymes from other animals.

Aldehyde Oxidase↗
PubMed2000

Degradation products generated by sonication of benzyl alcohol, a sample preparation solvent for the determination of residual solvents in pharmaceutical bulks, on capillary gas chromatography.

Benzyl alcohol used as the sample preparation solvent in the determination of residual solvents in pharmaceutical bulks yielded benzene, toluene, and benzaldehyde on capillary gas chromatography (GC) by sonication. The factors responsible for compounds generated are discussed. The quality of benzyl alcohol and the type of sonicator were not involved in the generation of benzene, toluene, and benzaldehyde, whereas matrix contributions were observed. The degradation profiles of benzyl alcohol and its analogous compounds obtained by pyrolysis-GC/mass spectrometric analysis were similar to those obtained by sonication, suggesting that benzyl alcohol is degraded by the high local heat generated by sonication. Consequently, no matter how long it may take to dissolve bulk substances in benzyl alcohol completely, we do not recommend the use of a sonicator in sample preparation for the determination of residual solvents in pharmaceutical bulks.

Benzyl Alcohols↗
PubMed2006

Inhibitory effects of Ruta graveolens L. extract on guinea pig liver aldehyde oxidase.

Ruta graveolens L. is a flavonoid-containing medicinal plant with various biological properties. In the present study, the effects of R. graveolens extract on aldehyde oxidase, a molybdenum hydroxylase, are investigated. Aldehyde oxidase was partially purified from liver homogenates of mature male guinea pigs by heat treatment and ammonium sulphate precipitation. The total extract was obtained by macerating the aerial parts of R. graveolens in MeOH 70% and the effect of this extract on the enzyme activity was assayed using phenanthridine, vanillin and benzaldehyde as substrates. Quercetin and its glycoside form, rutin were isolated, purified and identified from the extract and their inhibitory effects on the enzyme were investigated. R. graveolens extract exhibited a high inhibition on aldehyde oxidase activity (89-96%) at 100 microg/ml which was comparable with 10 microM of menadione, a specific potent inhibitor of aldehyde oxidase. The IC50 values for the inhibitory effect of extract against the oxidation of benzaldehyde, vanillin and phenanthridine were 10.4, 10.1, 43.2 microg/ml, respectively. Both quercetin and rutin at 10 microM caused 70-96% and 27-52% inhibition on the enzyme activity, respectively. Quercetin was more potent inhibitor than rutin, but both flavonols exerted their inhibitory effects mostly in a linear mixed-type.

Aldehyde Oxidase↗
PubMed2004

Comparison of the olfactory sensitivity of two sympatric steppe grasshopper species (Orthoptera: Acrididae) to plant volatile compounds.

Electroantennogram (EAG) responses of male and female Oedipodinae grasshoppers, Oedaleus decorus asiaticus B.-Bienko and Angaracris barabensis Pall to 37 plant volatile compounds were recorded. The two species have sympatric distribution and synchronous seasonal activity in Inner Mongolia Grasslands. They have different host plant preference with Oedaleus decorus asiaticus graminivorous and A. barabensis forbivorous. The EAG response profiles to 37 compounds of the two species and their both sexes were similar. Most of the green leaf volatiles elicited higher EAG responses in both species and sexes than terpenic compounds and some aromatic compounds. Strong EAG responses were elicited by 6-carbon alcohols (1-hexanol, Z-hexen-2-ol-1, E-2-hexen-1-ol, E-hexen-3-ol-1), aldehyde (E-2-hexen-1-al), ester (Z-hexen-3-yl acetate), and 7-carbon alcohols (1-heptanol) in both species and sexes. Monoterpenes with functional groups of alcohols and aldehydes were more stimulating than other monoterpenes tested. The sesquiterpenes tested elicited relatively low responses. Benzaldehyde elicited the highest responses for both species among aromatic components. Oedaleus decorus asiaticus showed higher EAG responses than A. barabensis to the green leaf volatiles, 1-decanol, 1-nonanol, 1-pentanol, hexanal, Z-hexen-3-yl acetate and to the sesquiterpenes (-)-trans-caryophyllene. Males have higher responses than females in Oedaleus decorus asiaticus. No sexual difference was observed in A. barabensis. Dose-dependent responses to six selected chemicals were observed from females. In both species, all the chemicals tested elicit EAG responses at concentration between 10(-3) mol/L and 10(-2) mol/L, except that the responses of A. barabensis to terpineol had a threshold concentration of 10(-2) mol/L benzaldehyde and 1-hexanol had the highest slopes in dose curves, while 1-octen-3-ol showed the smallest slope in responses to the six chemicals tested. Comparative studies on the responses of two antennal sections and the whole antenna to six selected chemicals were carried out using females of both species. A significant EAG response was only recorded from the distal part of the antenna and not from the proximal seven segments.

Alcohols↗
PubMed2003

Bacteriorhodopsin analogs from diphenylpolyene chromophores.

Chromophore-modified bacteriorhodopsin (bR) analogs are prepared, to study the nature of chromophore-protein interaction as well as to develop new bR analogs that can find applications as photoactive element in molecular electronic devices. This article describes the preparation and characterization of hitherto unknown bR analogs based on diphenylpolyene chromophores. Diphenylpolyene compounds, namely, 4-[(E)-2-phenylvinyl]benzaldehyde (1), 3-methyl-5-[4-[(E)-2-phenylvinyl]phenyl]penta-2E,4E-dienal (2), 4-[4-phenylbuta-1E,3E-dienyl]benzaldehyde (3) and 3-methyl-5-[4-[4-phenylbuta-lE,3E-dienyl]phenyl]penta-2E,4E-dienal (4), have been synthesized, and their interaction with bacterioopsin (bOP) has been studied. Whereas aldehydes 2 and 4 interact with bOP and yield bR analogs bR-2 and bR-4, aldehydes 1 and 3 do not yield any pigment. Analogs bR-2 and bR-4 have been characterized for their opsin shift, competitive binding, photochemical properties and fluorescence spectral behavior.

Journal Article↗
PubMed2004

EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone.

Electroantennogram (EAG) evaluation of selected compounds from wilted leaves of black poplar, Populus nigra, showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol, phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%, 50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles should modify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

Animals↗
PubMed2001

Tyrosine and phenylalanine catabolism by Lactobacillus cheese flavor adjuncts.

Bacterial metabolism of Tyr and Phe has been associated with the formation of aromatic compounds that impart barny-utensil and floral off-flavors in cheese. In an effort to identify possible mechanisms for the origin of these compounds in Cheddar cheese, we investigated Tyr and Phe catabolism by Lactobacillus casei and Lactobacillus helveticus cheese flavor adjuncts under simulated Cheddar cheese-ripening (pH 5.2, 4% NaCl, 15 degrees C, no sugar) conditions. Enzyme assays of cell-free extracts indicated that L. casei strains catabolize Tyr and Phe by successive, constitutively expressed transamination and dehydrogenation reactions. Similar results were obtained with L. helveticus strains, except that the dehydrogenase enzymes were induced during incubation under cheese-ripening conditions. Micellar electrokinetic capillary chromatography of supernatants from L. casei and L. helveticus strains incubated under simulated cheese-ripening conditions confirmed that Tyr and Phe transamination and dehydrogenation pathways were active in both species and also showed these reactions were reversible. Major products of Tyr catabolism were phydroxy phenyl lactic acid and p-hydroxy phenyl acetic acid, while Phe degradation gave rise to phenyl lactic acid, phenyl acetic acid, and benzoic acid. However, some of these products were likely formed by nonenzymatic processes, since spontaneous chemical degradation of the Tyr intermediate p-hydroxy phenyl pyruvic acid produced p-hydroxy phenyl acetic acid, p-hydroxy phenyl propionic acid, and p-hydroxy benzaldehyde, while chemical degradation of the Phe intermediate phenyl pyruvic acid gave rise to phenyl acetic acid, benzoic acid, phenethanol, phenyl propionic acid, and benzaldehyde.

Cheese↗
PubMed2000

Synthesis, antimicrobial testing and QSAR study of new 2-phenylethenylbenzothiazolium salts substituted by cyclic amines.

A series of new 2-phenylethenylbenzothiazolium salts substituted by cyclic amines has been prepared by the condensation of 2-methyl benzothiazolium bromide with substituted benzaldehydes. The nucleophilic substitution of 4-fluorobenzaldehyde with appropriate cyclic amines has been used to obtain the starting benzaldehydes. The compounds with saturated cycloamino substituents have shown enhanced activity against Euglena and some derivatives with piperazine substituent were active against Gram positive bacteria.

Animals↗
PubMed2001

SPME/GC-MS characterization of volatiles associated with methamphetamine: toward the development of a pseudomethamphetamine training material.

The headspace profiles of eleven methamphetamine (MA) samples have been analyzed using solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). Nine of the eleven are illicit MA seizures from the Southwest U.S. border. One sample is methamphetamine base synthesized in the Drug Enforcement Administration (DEA) Southwest Laboratory, and the remaining sample is pharmaceutical-grade methamphetamine hydrochloride that is used to make training aids for drug detecting canines. In addition. volatiles associated with 1-phenyl-2-propanone (P2P), a methamphetamine precursor, have been identified for comparison with those found in methamphetamine seizure and the two reference samples. Eighty-seven different compounds were identified from all the samples, not including simple hydrocarbons and aldehydes. Only seven occur consistently in all seizure samples, and these are: acetic acid, benzaldehyde, acetophenone, P2P, 1-phenyl-1,2-propanedione (P12P), 3-phenyl-3-buten-2-one, 1-chloro-1-phenyl-2-propanone. Dimethyl sulfone, a common cutting agent in methamphetamine. was found in six of the nine seizure materials. When the reference methamphetamine and P2P samples are included, only two compounds are common to all twelve samples, and these are benzaldehyde and P2P. As such, these two compounds are likely candidates for use in a pseudomethamphetamine (PM) formulation, and their effectiveness in eliciting a canine response is being evaluated before actual deployment.

Animals↗
PubMed2004

[Attraction effect of main volatile components from tea shoots and flowers on Sphaerophoria menthastri (Diptera: Syrphidae) and Chrysopa septempunctata (Neuroptera: Chrysopidae)].

The Y-olfactometer bioassays showed that the volatiles from tea aphids and tea aphid-damaged tea shoots (PHC) strongly attracted Sphaerophoria menthastri and Chrysopa septempunctata. At the dosage of 10(-4) g x ml(-1), S. menthastri selected geraniol and methyl salicylate from PHC, n-octanol from intact tea shoots (ITS), nerol from tea flowers (P < 0.01), and (E)-2-hexen-1-ol, E-2-hexenal, 1,3,6-octatriene-3,7-dimethyl and linalool from PHC (P < 0.05), while C. septempunctata selected n-octanol and hexanal from ITS (P < 0.05). At the dosage of 10(-2) g x ml(-1), S. menthastri selected hexanal, nerol and benzaldehyde from PHC (P < 0.05), while C. septempunctata selected hexanal, benzaldehyde, geraniol and (E)-2-hexen-1-ol (P < 0.05). The experimental results showed that besides aldehydes and methyl salicylate, geraniol, n-octanol and (E)-2-hexen-1-ol were significantly attractive to the natural enemies. The selective responses of natural enemies were restricted by thresholds. Both dosages of hexanal significantly attracted C. septempunctata. Nerol might be an infochemicals seducing S. menthastri to orient to tea flowers.

1-Octanol↗