Antifeedant and Termiticidal Activities of 6-Alkoxycoumarins and Related Analogs Against <Emphasis Type="Italic">Coptotermes formosanus</Emphasis> Shiraki

We synthesized 23 6-alkoxycoumarin derivatives, 20 of which are novel compounds. The structures of all compounds were confirmed by NMR, MS, and elemental analysis, and their antifeedant and termiticidal activities against Coptotermes formosanus Shiraki were examined. In a no-choice test, 6-(2-pentynyloxy)coumarin (2v), 6-(2-butynyloxy)coumarin (2u), 6-(2-octynyloxy)coumarin (2w), and 6-methoxycoumarin (2a), demonstrated high termiticidal activity at a concentration of 10 μmol. At a concentration of 5 μmol, 6-(2-butynyloxy)coumarin (2u) produced the highest mortality among the compounds tested. On the other hand, all of the 6-alkoxycoumarins showed antifeedant activity at both concentrations, except 6-octadecyloxycoumarin (2j) that was inactive at 5 μmol. Among the 23 compounds and the control, 6-ethoxycoumarin (2b), 6-isopropoxycoumarin (2d), and 6-isobutoxycoumarin (2f) exhibited the highest antifeedant activity with no mass loss (0.00%) at a concentration of 10 μmol. Our findings indicate that the presence of alkenyloxy and alkynyloxy groups was important for the termiticidal activity, while the incorporation of alkoxy groups with longer alkyl chains tended to reduce both the termiticidal and antifeedant activities. Furthermore, short chain alkoxy and arylalkoxy-substituted analogs showed good antifeedant activity, but methoxy groups on the benzene ring had a negative effect.     

Antitermitic Activities of Abietane-type Diterpenes from <Emphasis Type="Italic">Taxodium distichum</Emphasis> Cones

Eight known abietane-type diterpenes were isolated from the weak acidic fraction of the n-hexane extract from cones of Taxodium distichum, one of the extant, living fossil conifers. They were identified as 6,7-dehydroroyleanone (1), taxodal (2), taxodione (3), salvinolone (4), 14-deoxycoleon U (5), 5,6-dehydrosugiol (6), sandaracopimaric acid (7), and xanthoperol (8). The structures of these compounds were determined by comparison of NMR spectral data with published data. The antitermitic (termicidal and antifeedant) activities of the compounds 1–8 against the subterranean termite, Reticulitermes speratus Kolbe, were evaluated. Compounds 1 and 3 showed potent termicidal activity, and 5 and 8 showed potent antifeedant activity. Compound 1 was found to be one of the representative bioactive compounds in the n-hexane extract of T. distichum cones. Compounds 1–8, with the exception of 7, were oxides of ferruginol (9). Therefore, the presence of various oxidation forms of the abietane-type structure reflects their various bioactivities.     

New Nortriterpenoid and Ceramides From Stems and Leaves of Cultivated <Emphasis Type="Italic">Triumfetta cordifolia</Emphasis> A Rich (Tiliaceae)

To highlight the role of plants in traditional healing, the leaves and the stems of cultivated Triumfetta cordifolia were phytochemically studied yielding a new nor-ursane type (1), a new ceramide (2) and a new piperidinic ceramide derivative (3) named, respectively, 2α,19α-dihydroxy-3-oxo-23-nor-urs-12-en-28-oic acid, (2R)-2-hydroxy-N-[(2S,3S,4R,26E)-1,3,4-trihydroxy-26-triaconten-2-yl] tetradecanamide and (2R,8Z)-2-hydroxy-{(2S,3R,5R,6S)-3,5-dihydroxy-6-[(1E,5Z)-hexadeca-1,5-dienyl]-2-(β-d-glucopyranosyloxy)methyl piperidine-1-yl} tetracos-8-enamide (3). These were obtained together with lupeol (4), stigmasterol (5), 3-O-β-d-glucopyranoside of β-sitosterol (6), tormentic acid (7) from stems and heptadecanoic acid (8), β-carotene (9), oleanolic acid (10), and 24-hydroxytormentic acid (11) from leaves. The structures were determined on the basis of NMR data (¹H-, ¹³C-, 2D-NMR analyses), mass spectrometry and confirmed by chemical transformations as well as comparison of spectral data with those reported in the literature. The FRAP method was used to evaluate the antioxidant activity of fractions collected from flash chromatography and isolated compounds. Among the fractions, four reduced Fe^III-TPTZ to Fe^II-TPTZ while isolated pure compounds showed no activity.     

Structure-related insect antifeedant and growth regulating activities of some limonoids

Insect antifeedant and growth-regulating activities of 22 limonoids (both natural and their derivatives) againstSpodoptera litura were studied to understand the structure-related bioactivities of the limonoids. The C-seco limonoids (azadirachtins A, B, D, H, and I) were the most effective compounds as a group, while the intact limonoids (cedrelone and its derivatives) were the least effective. The cyclohexenone A ring and the-hydroxy enone group in the B ring appear to be important for antifeedant activity. The presence of a cyclohexenone or 1,2-epoxide in the A ring coupled with an-hydroxy enone in the B ring correlated well with growth regulatory activity. An acetoxy at C-7 instead of-hydroxy enone and perhaps the carbonyl at C-16 increase growth regulatory activity. Absence of 14–15 epoxide may not drastically reduce antifeedant activity and growth regulatory activity.     

Two New Eicosanoids with a Unique Isovalerianic Acid Ester Moiety from the South China Sea Gorgonian <Emphasis Type="Italic">Dichotella gemmacea</Emphasis>

Two new eicosanoids with a unique isovalerianic acid ester group at C-12, named dichotellates A (1) and B (2), were isolated from the gorgonian Dichotella gemmacea collected from the South China Sea using bioassay-guided fractionation. Their structures were established on the basis of extensive spectroscopic analysis including one-dimensional (1D) and two-dimensional (2D) NMR as well as high-resolution ESI-MS experiments. These two compounds were evaluated for their lethal activity toward brine shrimp Artemia salina and both showed weak activity.     

Constituents of Amomum tsao-ko and their radical scavenging and antioxidant activities

Constituents of the fruit of Amomum tsao-ko were investigated following a preliminary screening of the antioxidant activity of several extracts of the fruit of this plant that showed that the dichloromethane extract and the ethyl acetatesoluble and water-soluble fractions of the 70% aqueous acetone extract had higher activity than α-tocopherol and butylated hydroxytoluene (BHT). Eleven compounds were isolated from the ethyl acetate-soluble fraction, and their structures were elucidated as (+)-hannokinol (1), meso-hannokinol (2), (+)-epicatechin (3), (−)-catechin (4), β-sitosterol (5), β-sitosterol 3-O-glucoside (6), 2,6-dimethoxyphenol (7), protocatechualdehyde (8), protocatechuic acid (9), vanillic acid (10), and p-hydroxybenzoic acid (11) based on mass and various nuclear magnetic resonance (NMR) spectroscopic techniques. This is the first isolation of epicatechin and catechin from the genus Amomum. The radical scavenging activity of the isolated compounds was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and colorimetric and electron spin resonance (ESR) analyses. The antioxidant activity of the compounds was also determined based on the oxidative stability index (OSI). The catechins and catechol derivatives showed strong activities in both the DPPH radical scavenging activity and antioxidant activity assays.     

Antifungal Abietane-Type Diterpenes from the Cones of <Emphasis Type="Italic">Taxodium distichum</Emphasis> Rich

The chemical composition of Taxodium distichum cones and the antifungal activities of twelve diterpenoids against two wood decay fungi, Trametes versicolor (white-rot) and Fomitopsis palustris (brown-rot) were examined. The chemical composition of the major extractive fraction, the n-C₆H₁₄ extract, was evaluated and its antifungal properties were identified. Twelve diterpenoids including ten abietane-type components were isolated from the n-C₆H₁₄ extract: 6,7-dehydroferruginol (1), ferruginol (2), 6,7-dehydroroyleanone (3), sandaracopimaric acid (4), taxodione (5), taxodal (6), taxodone (7), sugiol (8), xanthoperol (9), salvinolone (10), 5,6-dehydrosugiol (11), and 14-deoxycoleon U (12). Compounds 5 and 12 were highly active against both wood-decay fungi. In particular, the activities of these compounds against F. palustris were potent. The results suggest that the position and the number of hydroxyl groups on abietane-type structures may be related to antifungal activities against T. versicolor and F. palustris.     

Four New Fatty Acid Esters from the Feces of <Emphasis Type="Italic">Trogopterus xanthipes</Emphasis>

Four new fatty acid esters have been isolated from Feces Trogopterus. Their structures were determined by spectroscopic and chemical methods to be bis(7-hydroxyheptyl) icosanedioate (1), bis(7-hydroxyheptyl) heptadecanedioate (2), bis(7-hydroxyheptyl) decanedioate (3), and bis(7-hydroxyheptyl) octanedioate (4). In the anticoagulative assay, compounds 3 and 4 had significant antithrombin activity.     

Two New Fatty Acid Derivatives from the Stem Bark of <Emphasis Type="Italic">Alchornea laxiflora</Emphasis> (Euphorbiaceae)

Euphorbiaceae is a family of plants used in traditional remedies in central Africa to treat selected diseases. Some of the phytochemical components in the stem bark of Alchornea laxiflora that have biochemical activity were identified. A number of novel compounds were isolated, including a new fatty acid ester, (1) a new ceramide, (2) some triterpenoids, (3–5), ellagic acid (6) and its derivatives (7, 8) were isolated. The structures of these compounds were determined on the basis of spectroscopic methods as well as HR-ESI-TOF-MS analysis, chemical transformation and by comparison of their physical and spectral data with those reported in the literature. The cytotoxicity of some isolated compounds was investigated against human promyelocytic leukaemia (HL60) cell line by using the MTT method. Compounds 1, 4 and 5 showed a cytotoxic activity with IC₅₀ at 58.7, 6.6 and 6.8 μM, respectively.     

Antifeedants and Feeding Stimulants in Bark Extracts of Ten Woody Non-host Species of the Pine Weevil, Hylobius abietis

Bark of ten woody species, known to be rejected as a food source by the pine weevil, Hylobius abietis, were sequentially extracted by a Soxhlet apparatus with pentane followed by methanol. Species were alder (Alnus glutinosa), aspen (Populus tremula), beech (Fagus sylvatica), guelder rose (Viburnum opulus), holly (Ilex aquifolium), horse chestnut (Aesculus hippocastanum), lilac (Syringa vulgaris), spindle tree (Evonymus europaeus), walnut (Juglans regia), and yew (Taxus baccata). Bark of each species was collected in southern Scandinavia during the summer. Resulting extracts were tested for antifeedant activity against the pine weevil by a micro-feeding choice assay. At a dose corresponding to that in the bark, methanol extracts from Aesculus, Taxus, Ilex, and Populus were antifeedant active, while pentane extracts of Aesculus, Fagus, Syringa, and Viburnum were stimulatory. Four known antifeedants against H. abietis, the straight-chained carboxylic acids, hexanoic and nonanoic acid (C6 and C9), carvone, and carvacrol were identified by gas chromatography (GC)–mass spectrometry (MS) in several extracts. The major constituents were identified and tested for feeding deterrence. The aromatic compounds benzyl alcohol and 2-phenylethanol are new non-host plant-derived feeding deterrents for the pine weevil. Additionally, two feeding stimulants, β-sitosterol and 5-(hydroxymethyl)-2-furaldehyde, were identified. One active methanol extract of Aesculus bark was sequentially fractionated by liquid chromatography, and major compounds were tentatively identified as branched alcohols and esters of hexanoic acid. Five commercially available hexanoate esters and two commercially available branched alcohols were identified as new active antifeedants. Both stimulatory and inhibiting compounds were found in the same extracts and co-eluted in the same or adjacent fractions. The mix of semiochemicals of opposite activity in each extract or fraction could explain the stimulatory-, inhibitory-, or sometimes neutral activity. Generally, such co-occurrence confounds the isolation of antifeedants.     

Two Novel Ceramides with a Phytosphingolipid and a Tertiary Amide Structure from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two novel ceramides, Candidamide A (1) with a phytosphingolipid structure, and Candidamide B (2) with a tertiary amide structure, together with 12 known compounds (3–14) have been isolated from the bulbs of Zephyranthes candida, The structures of 1 and 2 have been elucidated to be 1,3,5,6-tetrahydroxy-2-(2′-hydroxytetracosanoyl amino)-8-(E)-octadecadiene (1) and (2S,3S,4R,8E,2′R)-2-[N-(2′-hydroxyoctadecanoyl)-N-(1′′,2′′-dihydroxyethyl)-amino]-8-hexacosene-1,3,4-triol (2) on the basis of spectroscopic evidence including IR, MS, NMR (¹H-NMR, ¹³C-NMR, DEPT, ¹H–¹H COSY, HSQC, HMBC). The known compounds were identified as (2S)-3′,7-dihydroxy-4′-methoxyflavan (3), (2S)-4′-hydroxy-7-methoxyflavan (4), (2S)-4′,7-dihydroxyflavan (5), 7-hydroxy-3′, 4′-methylenedioxyflavan (6), ambrettolide (7), β-sitostero1 (8), β-daucosterin (9), rutin (10), pancratistatin (11), lycorine (12), haemanthidine (13), and haemanthamine (14). In the antimicrobial assay, candidamide A (1) and candidamide B (2) displayed moderate activities against bacteria Staphylococcus aureus and Escherichia coli, and fungi Aspergillus niger, Candida albicans and Trichophyton rubrum.     

Sex Pheromone of the Spanish Population of the Beet Armyworm <Emphasis Type="Italic">Spodoptera exigua</Emphasis>

The pheromone composition of the Spanish population of the beet armyworm (BAW), Spodoptera exigua (Lepidoptera: Noctuidae), was identified. Analysis of female gland extracts showed the presence of compounds Z9,E12–14:Ac (1), Z9–14:Ac (2), Z11–16:Ac (3), Z9,E12–14:OH (4), Z9–14:OH (5), and Z11–16:OH (6) in a ratio of 26:11:1:22:31:9. The amount of compound per gland ranged from 2.08 ng for 5 to 0.09 ng for 3. However, analysis of female volatiles by SPME revealed only the presence of compounds, 1, 2, 3, and 5 in a 34:40:4:22 ratio. In electroantennogram assays, compound 1 elicited the highest response, and the C14 acetates evoked higher electrophysiological responses than the corresponding alcohols or C16 isomers. In a wind tunnel, no behavioral difference was observed between formulations based on the gland extracts and female volatiles. In both cases, males responded as when virgin females were used as the attractant source. Compound 1 alone elicited upwind flight by males, but required the presence of compound 5 in a 80:20 to 40:60 ratio for full activity. Ternary mixtures of 1, 5 and the minor components did not improve the performance of the 1+5 blend in a 60:40 ratio. In the field, the mixture 1+5+3 in a 56:37:7 ratio was the most attractive formulation, and is expected to be useful in future pest control strategies.     

Novel ceramides and a new glucoceramide from the roots of <Emphasis Type="Italic">Incarvillea arguta</Emphasis>

Novel ceramides, rel-(3S,4S,5S)-3-[(2R)-2-hydroxycosanoyl-hexacosanoylamino]-4-hydroxy-5-[(4Z)-tetradecane-4-ene]-2,3,4,5-tetrahydrofuran (1a-g), and a new glucoceramide, 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octodecanetriol-8-ene (2) were isolated from the aqueous ethanolic extract of the roots of Incarvillea arguta, together with eight known compounds: β-sitosterol (3), oleanolic acid (4), ursolic acid (5), piperin (6), maslinic acid (7), β-sitosterol 6′-O-acyl-β-d-glucopyranoside (8), 8-epideoxyloganic acid (9), and plantarenaloside (10). Their structures were elucidated on the basis of spectral data including IR, MS, NMR [¹H NMR, ¹³C NMR (distortionless enhancement by polarization transfer), ¹H−¹H COSY, heteronuclear multiplequantum coherence, and heteronuclear multiple-bond coherence correlations]. The relative configurations were established by nuclear Overhauser effect spectroscopy experiments and by comparison of the NMR spectral data and coupling constants with those already reported in the literature.     

Evaluation of Dimboa Analogs as Antifeedants and Antibiotics Towards the Aphid Sitobion avenae in Artificial Diets

A total of 25 compounds including benzoxazinones, benzoxazolinones, and N-glyoxylamide derivatives were tested as antifeedants and antibiotics towards the aphid Sitobion avenae in diet bioassays. The antifeedant and mortality indexes increased with the presence of electron-donating groups in the 7 position of the benzoxazinone moiety, the replacement of the oxygen atom by sulfur in the heterocyclic ring, the presence of a hemiacetal instead of an acetal at C-2 of the benzoxazine moiety (and hence the possibility of ring opening), and the presence of a hydroxyl group at C-4 of the benzoxazine moiety (hydroxamic acid) instead of a hydrogen atom (lactam). The results support earlier hypotheses on the chemical bases for the mode of action of these compounds.     

Contact Sex Pheromone Components of the Seed Beetle, <Emphasis Type="BoldItalic">Callosobruchus analis</Emphasis> (F.)

Callosobruchus analis (Coleoptera: Chrysomelidae: Bruchinae), found throughout tropical Asia and Africa, is a pest of stored legumes. Previous work has shown that females of this species produce a contact sex pheromone that elicits copulatory behavior in males. Comparisons of copulatory activity between any two of four congeneric species suggest that the contact sex pheromones are species specific. In laboratory bioassays, male C. analis exhibited copulatory behavior to a female dummy to which a crude extract of virgin females was applied. The extract had been collected by a filter paper method and was purified by acid–base partition and chromatographic techniques. Gas chromatography-mass spectrometry (GC-MS) analyses of active fractions revealed that the active compounds were 2,6-dimethyloctane-1,8-dioic acid (1) and callosobruchusic acid, (E)-3,7-dimethyl-2-octene-1,8-dioic acid (2), previously identified as contact sex pheromones of Callosobruchus maculatus (F.) and C. chinensis (L.), respectively. The stereoisomeric and chemical compositions were determined by the 2D-HPLC-Ohrui-Akasaka method as (2S,6R)-1:(S)-2 = 1.8:1, which meant that both compounds in C. analis were stereochemically pure, unlike the case of C. maculatus and C. chinensis. An examination of the influence of synthetic pheromone compounds on male copulatory activity revealed that (2S,6R)-1 is the main component, and that (S)-2 has an additive effect. In the examination of the stereochemistry-activity relationship, no copulatory behavior was elicited by (2R,6S)-1, and, furthermore, the enantiomer significantly masked the pheromonal activity of (2S,6R)-1. Glass rod dummy assays also suggested the presence of synergists. These results could elucidate the specificity of mate recognition in C. analis.     

New fatty acid derivatives from <Emphasis Type="Italic">Homaxinella</Emphasis> sp., a marine sponge

Fractionation of the MeOH extract of Homaxinella sp., a marine sponge, led to the isolation of a sodium salt of a new brominated FA (1), two new MG (2 and 4), and a new lysoPC (6). The geometry of the double bonds in 1 and 2 was defined by comparison of the NMR chemical shifts of the allylic carbons, nuclear Overhauser effect spectroscopy correlations of the allylic protons, and coupling constants of the vinylic protons with those reported. Evidence mainly from NMR and MS analyses established the planar structures of the compounds. Compounds 1, 2, 4, and 6 were evaluated for cytotoxicity against a panel of five human solid tumor cell lines. Only compound 1 showed moderate activity.     

<Emphasis Type="Italic">E</Emphasis>-2-Ethylhexenal, <Emphasis Type="Italic">E</Emphasis>-2-Ethyl-2-Hexenol,Mellein, and 4-Hydroxymellein in <Emphasis Type="Italic">Camponotus</Emphasis> Species from Brunei

E-2-ethyl-2-hexen-1-ol (1), mellein (4), and 4-hydroxymellein (5) were identified as the major volatile compounds in the head and/or thorax of Camponotus quadrisectus. Neither 1 nor 5 have been previously detected in insects. Also identified were small amounts of m-cresol (2) and 6-methyl salicylic acid (3). E-2-ethylhexenal (6) and small amounts of 3 were identified in heads of Camponotus irritibilis from Kuala Belalong, Brunei. Compounds 2–4 occur in other Bornean camponotines with hypertrophied mandibular glands, and 4 is widespread in the tribe. The possibility of semiochemical parsimony (multiple functions) for these mandibular gland compounds is reviewed in the context of existing data on mandibular gland products of other camponotines, reported biological activities of the compounds, and secondary loss of metapleural glands in this ant group.     

Patterns of Bioactivity and Herbivory on Nothofagus Species from Chile and New Zealand

Nothofagus species from Chile and New Zealand were surveyed in the field for invertebrate abundance and leaf feeding damage and in the laboratory for antifeedant activity against leafrollers (Ctenopsteustis obliquana, Epiphyas postvittana), deterrent activity against pea aphid (Acyrthosiphon pisum), insect growth regulatory activity (Oncopeltus fasciatus), nematicidal activity (Caenorhabditis elegans), antibiotic activity (Pseudomonas solanaciarium), and general toxicity. A data matrix indicated that N. alessandri and N. pumilio most likely have a chemical barrier to insect attack as leaves showed low faunal abundance, low herbivory, and activity in the leafroller antifeedant, aphid deterrent, and nematicidal assays. A chemical examination of N. alessandri that used the leafroller antifeedant test to guide the separation yielded an active fraction containing the flavonoid, galangin, and the stilbene, pinosylvin, which appear to act in concert to deter leafroller feeding. The discovery of the phytoalexin, pinosylvin, in the leaves, raises the possibility that Nothofagus in general, and N. alessandri in particular, may have induced chemical defense mechanisms.     

Antifeedants against <Emphasis Type="Italic">Hylobius abietis</Emphasis> Pine Weevils: An Active Compound In Extract of Bark of <Emphasis Type="Italic">Tilia cordata</Emphasis> Linden

Linden (Tilia cordata) bark was shown to contain an antifeedant effective against the large pine weevil, Hylobius abietis. Soxhlet extraction of inner and outer bark resulted in an extract that showed antifeedant activity in a microfeeding assay. The extract was fractionated by chromatography on silica gel using gradient elution with solvents of increasing polarity. The content of the fractions obtained was monitored by thin layer- and gas chromatography. Fractions of similar chemical composition were merged. Two of the 17 fractions showed antifeedant activity in the microfeeding assay. Nonanoic acid was identified in both of these fractions. Subsequent testing in the microfeeding assay showed that nonanoic acid possessed strong antifeedant activity against H. abietis adults.     

Bioactive compounds from the bark of Broussonetia papyrifera after solid fermentation with a white rot fungus Perenniporia tephropora

Abstract

In this study, potential bioactive compounds in the products of the solid fermentation of the paper mulberry tree bark (Broussonetia papyrifera) with a white rot fungus (Perenniporia tephropora) were investigated. Fractionation of methanolic extracts from the fermented products of the bark led to the isolation of 10 known compounds, namely broussonin B (1), broussonin A (2), 7,4'-dihydroxy-3'-prenylflavan (3), cathayanon H (4), broussoflavonol B (5), isoliquiritigenin (6), broussochalcone B (7), glyasperin A (8), marmesin (9), and vomifoliol (10). Their structures were determined by spectroscopic analysis (including considerations of MS, ¹H, ¹³C NMR, COSY, HMQC, and HMBC spectra) and compared with structures that had been published in the literature. Of these compounds identified, cathayanon H (4) and glyasperin A (8) were isolated for the first time from the paper mulberry tree. Vomifoliol (10) was produced from the bark only after fermentation with white rot fungi. It was observed that concentrations of marmesin (9) and vomifoliol (10) generally increased with an increase in fermentation time, whereas concentration of compounds 1?8 in the fermented products decreased during the same period. Biological tests showed that the tyrosinase inhibitory activity of marmesin (9) (IC₅₀ = 168.0?μM) was similar to that of arbutin, a well-known tyrosinase inhibitor, whereas vomifoliol (10) exhibited no tyrosinase inhibition activity at any concentration higher than 2?mM. Accordingly, both solids and the liquid broth left after fermentation of the paper mulberry tree bark with the aforementioned white rot fungus could be developed for potential use in industrial applications.