Pungent Alkamides from Spilanthes acmella L. var. oleracea Clarke

A main pungent amide, spilanthol (1), and three alkamides, (2E)-N-(2-methylbutyl)-2-undecene-8,10-diynamide (2), (2E,7Z)-N-isobutyl-2,7-tridecadiene-10,12-diynamide (3), and (7Z)-N-isobutyl-7-tridecene-10,12-diynamide (4) were isolated from the flower heads of Spilanthes acmella L. var. oleracea Clarke. Their structures were established by spectroscopic methods. Compounds 2 and 4 were new and 3 was found for the first time in Spilanthes species. Chemotaxonomic aspects are discussed.     

Patterns in Volatile Emission of Different Aerial Parts of Caper (Capparis spinosa L.)

We analyzed the spontaneous volatile emission of different aerial parts of the caper (Capparis spinosa L.) by HS‐SPME‐GC/MS. We identified 178 different compounds of which, in different proportions based on the sample type, the main ones were (E)‐β‐ocimene, methyl benzoate, linalool, β‐caryophyllene, α‐guaiene, germacrene D, bicyclogermacrene, germacrene B, (E)‐nerolidol, isopropyl tetradecanoate, and hexahydrofarnesyl acetone. The multivariate statistical analyses seem to point out that the parameter leading the emission patterns is the function of the analyzed sample; the flower samples showed differences in the emission profile between their fertile and sterile portions and between the other parts of the plant. The green parts emission profiles group together in a cluster and are different from those of seeds and fruits. We also hydrodistilled fully bloomed caper flowers, whose volatile oil showed significant differences in the composition from those of other parts of the plant reported.     

Volatiles released from cotton plants in response to<Emphasis Type="Italic"> Helicoverpa zea</Emphasis> feeding damage on cotton flower buds

Feeding of Helicoverpa zea larvae on cotton (Gossypium hirsutum L.) flower buds (squares) for 24 or 48 h induced the release of a number of terpenes [(E)--ocimene, linalool, (E)--farnesene, (E,E)--farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene], isomeric hexenyl butyrates, 2-methylbutyrates, indole and (Z)-3-hexenyl acetate. These compounds are not released in significant amounts from undamaged squares and freshly damaged squares. The release of inducible compounds was not limited to the damaged squares themselves. The compounds were also released systemically from the upper undamaged leaves of the same plant after 72 h. However, the composition of the blend of systemically released volatiles differed from the blend released by damaged squares. The compounds that were systemically released from undamaged leaves in response to feeding on the squares were (Z)-3-hexenyl acetate, (E)--ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, (E)--farnesene, (E,E)--farnesene, and indole. This study shows that insect damage inflicted to the reproductive parts of a plant causes a systemic emission of volatiles from its vegetative parts.     

Diversity in the composition of monoterpenoids of Origanum microphyllum (Labiatae)

The variability in the composition of the volatile compounds of Origanum microphyllum, a species endemic to Crete, was examined. Headspace analysis was carried out on leaves from five natural populations and subsequently from the same plants from uniform cultivation. Plants were rich in cis-sabinene-hydrate (3–68%), sabinene (3–45%) and trans-sabinene-hydrate (0.5–34%). Four chemical profiles were distinguished, the extremes being either rich in sabinene and trans-sabinene-hydrate, or rich in cis-sabinene-hydrate. Furthermore, different chemical profiles were present in all populations to varying proportions, which explains the high variation observed within each population and the apparent small variation between them. The pattern of distribution of the different profiles among populations suggested a possible closer relation between neighbouring populations. There is a strong evidence of genetic control in the composition of the volatiles of O. microphyllum since it remained nearly unchanged in cultivation when the same plants were examined a year later.     

武夷山不同龄级香果树开花物候及其生殖特性

该研究采用固定样地观测研究了不同龄级香果树的开花物候和生殖特性,分析了物候指数与生殖构件之间的相关性。结果表明：香果树单花花期一般为5~9 d,平均为6.79 d,随着树龄增大,其单花花期呈幂函数增长趋势;不同树龄香果树的始花期不同,但终花期基本一致;随着树龄的增大,始花期逐渐提前,花期持续时间延长。20~50 a树龄的香果树始花期约为8月9日,花期持续时间最短,仅为36 d。110~140 a树龄的香果树始花期约为7月15日,花期持续时间为61 d;对于单株母树来讲,香果树的花枝数,花朵总数以及果实总数随着树龄的增大均显著增加;单花枝产花量随着树龄的增加呈上升趋势,单花枝产果实数量呈先上升后下降的趋势;香果树花枝和单花枝产花量在树冠方位上的分布由大到小依次为南>东/西>北、上>中>下,但单花枝果实数量则表现出不同规律,即东>南>西>北、中>下>上。香果树具有花多果少现象,开花物候指数与生殖构件数量间的相关性分析表明,其花期持续时间与花枝数、花数和果实数均存在极显著正相关关系,始花期与生殖构件数量呈极显著负相关关系,而物候指数与香果树树龄亦存在显著相关关系。     

Antennal response of codling moth males, Cydia pomonella L. (Lepidoptera: Tortricidae), to the geometric isomers of codlemone and codlemone acetate

Single sensillum recordings from Cydia pomonella male antennae showed three different types of receptor neurons. The most abundant type was most sensitive to the main pheromone compound (E,E)-8,10-dodecadienol, while its response to the geometric isomers E,Z, Z,E and Z,Z was comparable to a tenfold lower dose of (E,E)-8,10-dodecadienol. This neuron type also responded to the four behaviorally antagonistic isomers of (Δ,Δ)-8,10-dodecadienyl acetate, among which it was most sensitive to the E,E isomer. Cross-adaptation studies showed that these compounds were all detected by the same receptor neuron type. Receptor neurons specifically tuned to (E,Z) or (Z,Z)-8,10-dodecadienol were not found, although these two compounds are behaviorally active. A second type of receptor neuron responded to all isomers of (Δ,Δ)-8,10-dodecadienyl acetate and was most sensitive to the E,E isomer. This neuron type did not respond to any of the isomers of (Δ,Δ)-8,10-dodecadienol. A third receptor neuron type was highly sensitive to the plant compound α-farnesene. The finding that the receptor neuron type tuned to the main pheromone compound responded even to strong behavioral antagonists aids the interpretation of ongoing behavioral studies for the development of the mating disruption technique in codling moth. Accepted: 3 March 2000     

Ionylideneacetic Acids and Abscisic Acid Biosynthesis by Cercospora rosicola

Several compounds having the basic α-ionylideneacetic acid structure were tested in Cercospora rosicola resuspensions. At 100 μm, all the compounds inhibited abscisic acid (ABA) biosynthesis. Time studies with unlabelled and deuterated (2Z,4E)- and (2E,4E)-α-ionylideneacetic acids showed rapid conversions into both (2Z,4E)- and (2E,4E)-4′-keto-α-ionylideneacetic acids as major products. Incorporation of the label into ABA was specific for the 2Z,4E-isomer. Minor products, identified by GC-MS, were (2Z,4E)- and (2E,4E)-4′-hydroxy-α-ionylideneacetic acids and (2Z,4E)-1′-hydroxy-α-ionylideneacetic acid. The conversion to (2Z,4E)-l′-hydroxy-α-ionylideneacetic acid has not been previously reported and was specific for the 2Z,4E-isomer. A time study for the conversion of methyl esters of [²H₃]-(2Z,4E)- and [²H₃]-(2E,4E)-4′-keto-α-ionylideneacetates showed a slow introduction of the l′-hydroxyl group and specificity for 2Z,4E-isomer. Conversion of the ethyl esters of (2Z,4E)- and (2E,4E)-l′-hydroxy-α-ionylideneacetates into the ethyl esters of both ABA and (2E,4E)-ABA demonstrated that ABA can be formed by oxidation of the 4′-position after the insertion of the 1′-hydroxy group. The ethyl 1′-hydroxy acids were also isomerized to the corresponding ethyl (2Z,4E)- and ethyl (2E,4E)-3′-hydroxy-β-ionylideneacetates. Ethyl (2Z,4E)-1′-hydroxy acid also gave small amounts of ethyl l′,4′-trans-diol of ABA. These results suggest that ABA may be formed through a (2Z,4E)-1′-hydroxy-α-ionylidene-type intermediate in addition to the previously proposed route through (2Z,4E)-4′-keto-α-ionylideneacetic acid.     

Aroma Profile of Rubus ulmifolius Flowers and Fruits During Different Ontogenetic Phases

The chemical composition of spontaneous volatile emission from Rubus ulmifolius flowers and fruits during different stages of development was evaluated by HS‐SPME‐GC/MS. In total, 155 chemical compounds were identified accounting 84.6 – 99.4% of whole aroma profile of flowers samples and 92.4 – 96.6% for fruit samples. The main constituents were α‐copaene, β‐caryophyllene, germacrene D, (E,E)‐α‐farnesene, 1,7‐octadien‐3‐one,2‐methyl‐6‐methylene, tridecane, (E)‐2‐hexenol acetate, (E)‐3‐hexenol acetate and cyperene. The results give a chemotaxonomic contribution to the characterization of the VOCs emitted from flowers and fruits during their ontogenic development.     

Male bumble bee pheromonal components in the scent of deceit pollinated orchids; unrecognized pollinator cues?

The pollination of the non-rewarding Orchis pauciflora was studied. The most abundant visitors of O. pauciflora were B. terrestris queens. The fragrance of O. pauciflora inflorescence was dominated by a sesquiterpene (E)-β-farnesene. (E,E)-α-Farnesene, (E)-2,3-dihydrofarnesol, geranylcitronellol, and the monoterpenes limonene and 1,8-cineol were found among less abundant constituents. The sesqui- and diterpenes detected in O. pauciflora fragrance are frequent constituents of male marking pheromones of many bumble bee species. Enantioselective analysis of O. pauciflora scent and B. terrestris male marking pheromone revealed the presence of the (S)-isomer of (E)-2,3-dihydrofarnesol in both samples, and electrophysiological experiments showed that mainly the (S)-isomer activated the antennal receptors. In field experiments, O. pauciflora inflorescences were enriched with the main compound (E)-β-farnesene resulting in significantly increased pollinia export. We here discuss the chemical similarities between orchid and bumble bees and whether the presence of bumble bee male pheromone components in O. pauciflora fragrance increases its fitness. Dedicated to the late Professor Emeritus Bertil Kullenberg for his fundamental contribution to the research in the field of chemical ecology     

A computational study of the mechanism of the unimolecular elimination of <Emphasis Type="Italic">α</Emphasis>,<Emphasis Type="Italic">β</Emphasis>-unsaturated aldehydes in the gas phase

The mechanism for the decarbonylation of (E)-2-butenal and (E)-2-methyl-3-pheny-2-propenal was studied with different levels of ab initio and DFT methods. Reactants, products and transition structures were optimized for two kinds of reaction channel: a one-step reaction which involves a three-membered cyclic transition state, and a two-step reaction which involves an initial four-membered cyclic transition state. According to our calculations, these two possible mechanisms entail similar energetic costs, and there are only small differences depending on the reactant. The elimination of (E)-2-methyl-3-pheny-2-propenal yields different products depending on the channel followed. Only one of the three possible one-step mechanisms leads directly to (E)-β-methylstyrene (the main product according to experiment). This fact is reasonably well reproduced by our results, since the corresponding transition state gave rise to the lowest activation Gibbs free energy.     

Attraction of codling moth males to apple volatiles

The attraction of the codling moth, Cydia pomonella, to apple volatile compounds known to elicit an antennal response was tested both in the field and in a wind tunnel. In the field, (E)‐β‐farnesene captured male moths. The addition of other apple volatiles, including (E,E)‐α‐farnesene, linalool, or (E,E)‐farnesol to (E)‐β‐farnesene did not significantly augment trap catch. Few females were caught in traps which also caught male moths, but female captures were not significantly different from blank traps. In the wind tunnel, males were attracted to (E,E)‐farnesol, but not to (E)‐β‐farnesene. The addition of (E,E)‐α‐farnesene to (E)‐β‐farnesene had a synergistic effect on male attraction. The male behavioural sequence elicited by plant volatiles, including upwind flight behaviour, was indistinguishable from the behaviour elicited by sex pheromone.     

Characterization of the Photoperiodic Response of Post-flowering Development in Maturity Isolines of Soyabean [Glycine max(L.) Merrill] 'Clark'

Plants of all eight isolines of three maturity genes (all combinationsof two alleles at the three lociE₁/e₁,E₂/e₂,E₃/e₃) of soyabean[Glycine max(L.) Merrill] were grown in four different photoperiods(12, 13, 14 or 15 h d^-1) at 30/24 °C from first flower openingto harvest maturity. Photoperiod, isoline, and their interaction,affected significantly (P<0.01) the duration between firstand last flowering, and reproductive duration. The interactionsbetween genotype and photoperiod were sufficiently strong thatconsiderable differences in these durations were detected amongisolines in the least-inductive environment (15 h d^-1) whereasdifferences were negligible in the most-inductive regime (12h d^-1). There was a negative linear relation between photoperiodand both rate of progress from the appearance of the first tothe last flower, and rate of progress from first flowering toharvest maturity; sensitivity to photoperiod varied (P<0.05)six- and five-fold, respectively, among the extreme isolines(e₁e₂e₃andE₁E₂E₃). The three dominant allelesE₁,E₂andE₃, singly,had comparatively little effect on post-flowering traits, butconsiderable epistasis (particularly betweenE₁andE₂) was detectedfor sensitivity to photoperiod in respect of rates of progressfrom the appearance of the first to the last flower, and fromfirst flower to harvest maturity. Thus the large variationsdetected for these traits are the consequence of genexgene (xgene)xenvironmentinteractions.Copyright 1998 Annals of Botany Company. Glycine max(L.) Merrill, soyabean, maturity genes, flowering, photoperiod.     

Design, synthesis and in vitro evaluation of novel chroman-4-one, chroman, and 2H-chromene derivatives as human rhinovirus capsid-binding inhibitors

As part of an effort to generate broad-spectrum inhibitors of rhinovirus replication, novel series of (E)-3-[(E)-3-phenylallylidene]chroman-4-ones 1a–e, (E)-3-(3-phenylprop-2-yn-1-ylidene)chroman-4-ones 2a and 2b, (Z)-3-[(E)-3-phenylallylidene]chromans 3a–e, and (E)-3-(3-phenylprop-1-en-1-yl)-2H-chromenes 4a–d were designed and synthesized. All the compounds were tested in vitro for their efficacy against infection by human rhinovirus (HRV) 1B and 14, two representative serotypes for rhinovirus group B and A, respectively. Most of the analogues were found to be potent and selective inhibitors of both HRVs, although HRV 1B was generally more susceptible than HRV 14. Mechanism of action studies of (E)-6-chloro-3-(3-phenylprop-1-en-1-yl)-2H-chromene 4b, the most potent compound on HRV 1B infection, suggested that 4b behaves as a capsid-binder probably acting at the uncoating level.     

Volatiles released from bean plants in response to agromyzid flies

Liriomyza sativae Blanchard and Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) are two invasive flies in China that have caused economical damage on vegetables and ornamental plants. In this article, we report the profiles of emitted volatiles from healthy, mechanically damaged, and leafminer-damaged bean, Phaseolus vulgaris L., plants. Among 25 emitted volatiles identified, (E)-2-hexen-1-al, (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, (syn)- and (anti)-2-methylpropanal oxime, (syn)-2-methylbutanal oxime, linalool, and (E,E)-α-farnesene were consistently released from damaged bean plants. Combined amounts of these nine compounds made up more than 70% of the total volatiles emitted from each treatment. No qualitative differences in volatile emission were found between bean plants damaged by the two fly species; however, amounts of several major compounds induced by L. huidobrensis damage were significantly higher than those from plants damaged by L. sativae. The mechanically damaged plants released a higher proportion of green leaf volatiles than plants in the other treatments, whereas leafminer-damaged plants produced more terpenoids and oximes. Furthermore, the volatile profiles emitted from plants, damaged by adult leafminers, by second instar larvae, and even the plants with empty mines left by leafminer larvae (the pupal stage) were significantly different. The identification of volatile oximes released from damaged plants was confirmed and is discussed in a behavioral and biological control context.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Synthesis of (S)-13-Hydroxy (2E,4E,8E)- and (2E,4E,8Z)-Tetradecatrienoic Acids

The syntheses of (S)-13-hydroxy-(2E,4E,8E)-tetradecatrienoic acid (1) and (2E,4E,8Z)-tetradecatrienoic acid (2) were carried out by using the Wittig reaction as the key step. The asymmetric center at C-13 and the double bond between C-8 and C-9 for natural compound 1 were reconfirmed as being of (S) configuration and E, respectively.

The relationship between the structure of the unsaturated hydroxy fatty acids and their inhibitory effect on the growth of lettuce was investigated.     

Farnesyl and α-Ionylideneethyl Tertiary and Quaternary Amines: Their Influence on Abscisic Acid Biosynthesis by Cercospora rosicola

Farnesyl and α-ionylideneethyl compounds with tertiary and quaternary amine functional groups were synthesized and their effects on abscisic acid (ABA) biosynthesis of Cercospora rosicola observed. The trimethylammonium compounds were lethal at 10 μm and inhibitory at 10 μm, but lesser amounts of α-ionylideneethyltrimethylammonium iodide enhanced ABA biosynthesis. N,N-Dimethylfarnesylamine had little effect on ABA biosynthesis. N,N-Dimethyl (2Z,4E)- and (2E,4E)-α-ionylideneethylamines inhibited ABA biosynthesis at 100 μm but had no or little effect at lower concentrations. Farnesol and farnesylpyrophosphate (FPP) enhanced ABA biosynthesis. FPP appears to be both a precursor and an inducer and farnesol is an inducer of ABA biosynthesis. N,N-Dimethyl (2Z,4E)- and (2E,4E)-α-ionylideneethylamines were converted to N,N-dimethyl (2Z,4E)- and (2E,4E)-4′-keto-α-ionylideneethylamines, respectively. These conversions are analogous to those reported for α-ionone and α-ionylideneacetic acids and show that basic as well as acidic and neutral compounds with α-ionone type rings can undergo oxidation at the 4′-position. α-Ionylideneacetic acids inhibited growth of C. rosicola and the dimethylamines enhanced growth. Complete feedback inhibition was obtained with 400 μm of ABA.     

Synthesis and Biological Activities of Novel (Z)-/(E)-Anisaldehyde-Based Oxime Ester Compounds

In search of novel natural product-based bioactive molecules, twenty (ten pairs) novel (Z)-/(E)-anisaldehyde-based oxime ester compounds were designed and synthesized by using anisaldehyde as starting material. Structural characterization of the target compounds was carried out by NMR, FT-IR, ESI-MS, and elemental analysis. Their herbicidal and antifungal activities were preliminarily tested. As a result, at 50 μg/mL, compound (E)- 5b exhibited excellent to good inhibition rates of 92.3 %, 79.2 %, and 73.9 %, against Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, and Bipolaris maydis, respectively, better than or comparable to that of the positive control chlorothalonil. In addition, at 100 μg/mL, compounds (E)- 5b , (E)- 5f , (Z)- 5f and (E)- 5d exhibited excellent to good inhibition rates of 85.8 %, 82.9 %, 78.6 % and 64.2 %, respectively, against the root-growth of rape (B. campestris), much better than that of the positive control flumioxazin. The bioassay result also showed that the synthesized compounds had obvious differences in antifungal and herbicidal activities between (Z)- and (E)-isomers. Preliminary structure–activity relationship was also discussed by theoretical calculation.     

New semicarbazones as gorge-spanning ligands of acetylcholinesterase and potential new drugs against Alzheimer’s disease: Synthesis,molecular modeling,NMR, and biological evaluation

Two new compounds (E)-2-(5,7-dibromo-3,3-dimethyl-3,4-dihydroacridin-1(2H)-ylidene)hydrazinecarbothiomide (3) and (E)-2-(5,7-dibromo-3,3-dimethyl-3,4-dhihydroacridin-1(2H)-ylidene)hydrazinecarboxamide (4) were synthesized and evaluated for their anticholinesterase activities. In vitro tests performed by NMR and Ellman’s tests, pointed to a mixed kinetic mechanism for the inhibition of acetylcholinesterase (AChE). This result was corroborated through further docking and molecular dynamics studies, suggesting that the new compounds can work as gorge-spanning ligands by interacting with two different binding sites inside AChE. Also, in silico toxicity evaluation suggested that these new compounds can be less toxic than tacrine.     

Electrophysiological and behavioral responses of Helicoverpa assulta (Lepidoptera: Noctuidae) to tobacco volatiles

The Oriental tobacco budworm moth, Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae), is a serious pest on tobacco in China. The flowering stage of the host plant is one of the most attractive stages to H. assulta for feeding and oviposition. Nine electrophysiologically active compounds in tobacco headspace at flower stage were detected by gas chromatography?Celectroantennographic detection (GC?CEAD). These compounds were subsequently identified by gas chromatography-mass spectrometry (GC?CMS) as (E)-??-ocimene, octanal, (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, nonanal, (Z)-3-hexenyl-2-methyl butyrate, decanal, linalool, and (E)-??-caryophyllene. The synthetic blend containing nine of the above compounds attracted mated H. assulta females from a distance by upwind oriented flight. Selected subtraction assays showed that the 4-component mixture of (E)-??-ocimene, (Z)-3-hexenyl acetate, nonanal, and (E)-??-caryophyllene elicited equivalent levels of attraction as the 9-component mixture. The removal of any of the four compounds from the 4-component blend resulted in a significant decrease in female upwind flight behavior.     

Dual Antagonism of Aldehydes and Epiphytic Bacteria from Strawberry Leaf Surfaces against the Pathogenic Fungus Botrytis cinerea in vitro

Dual culture experiments were conducted in vitro to evaluate the potential combined biological effect of epiphytic bacteria and plant volatiles formed during fatty acids degradation on the pathogenic fungus Botrytis cinerea. The aliphatic aldehydes hexanal, (E)-2-hexenal, (Z)-3-hexenal and (E)-2-nonenal showed an enhancing effect on the antagonistic interaction between the epiphytic bacteria Pseudomonas lurida, Pseudomonas rhizosphaerae, Pseudomonas parafulva, and Bacillus megaterium against the pathogenic fungus. The unsaturated aldehydes were found to be the most potent with the minimum effective concentration being 1 ppm. Increasing volatile concentrations led to the inhibition of Botrytis cinerea growth with concomitant increase of colony diameters of epiphytic bacteria. Especially (E)-2-nonenal showed a stronger inhibitory effect on different strains of the plant pathogenic fungus Botrytis cinerea than on the epiphytic bacteria. These results suggest that co-application of antagonistic bacteria with natural plant volatiles can enhance the effectiveness of the biocontrol agents against B. cinerea.