Insecticidal and Attractant Activities of Magnolia citrata Leaf Essential Oil against Two Major Pests from Diptera: Aedes aegypti (Culicidae) and Ceratitis capitata (Tephritidae).

In this study, Magnolia citrata Noot and Chalermglin (Magnoliaceae) essential oil (MCEO) was evaluated for insecticidal activity against the yellow fever mosquito Aedes aegypti and attractant activity for the Mediterranean fruit fly Ceratitis capitata. The leaves of Magnolia citrata (Gioi chanh) were collected from northwestern Vietnam, and the water-distilled MCEO was analyzed by gas-chromatography and mass spectrometry (GC-MS). The major constituents of MCEO were identified as linalool 19%, geranial 16%, citronellal 14%, neral 14%, and sabinene 12%. MCEO showed 100% mortality at 1 µg/µL against 1st instar larvae of Ae. aegypti (Orlando strain, ORL), and the oil exhibited 54% (ORL) and 68% (Puerto Rico strain) mortality at 5 µg/mosquito against Ae. aegypti adult females. Initial screens showed that MCEO had weak insecticidal activity compared to the positive control permethrin. In bioassays with sterile male C. capitata, MCEO exhibited moderately strong attraction, comparable to that observed with a positive control, Tetradenia riparia essential oil (TREO). Herein, the insecticidal and attractant activities of MCEO are reported for the first time.

Chemical Characterization and Biological Activity of the Mastic Gum Essential Oils of Pistacia lentiscus Var. Chia from Turkey.

The essential oils (EOs) were isolated by hydrodistillation from wild and cultivated Pistacia lentiscus L. var. chia-mastic gum tree (Anacardiaceae) from two natural habitats, namely from Cesme-Uzunkoy (1) and Mordogan (2), and one cultivated source, Cesme-Germiyan (3), in Izmir, Turkey. This comparative study evaluated the chemical composition and biological activity of mastic gum essential oils (MGEOs). For this purpose, MGEOs 1-3 were analyzed by gas chromatography-flame ionization detection (GC-FID), gas chromatography-mass spectrometry (GC-MS), and chiral GC for α-pinene. Laboratory assays were conducted to assess for potential in vitro cytotoxicity (multiple in vitro cancer cell lines), antimicrobial properties (five bacterial species and yeast), anti-inflammatory activity (inhibition of inducible nitric oxide synthase, iNOS), and the attraction of Ceratitis capitata (Mediterranean fruit fly, medfly), respectively. Chemical analysis indicated that MGEOs 1 and 2 were rich in α-pinene (56.2% and 51.9%), myrcene (20.1% and 18.6%), and ß-pinene (2.7% and 3.1%), respectively; whereas MGEO-3 was characterized by a high level of α-pinene (70.8%), followed by ß-pinene (5.7%) and myrcene (2.5%). Chiral GC analyses showed that concentration ratios between (-)/(+)-α-pinene and (-)-α-pinene/myrcene allowed for differentiation between wild and cultivated MGEO sources. In biological assays, MGEOs 1-3 did not exhibit significant antimicrobial effects against the pathogens evaluated and were not strong attractants of male medflies; however, all three MGEOs displayed a dose-dependent inhibition of iNOS, and MGEOs 1 and 2 exhibited selective in vitro cytotoxicity against human cancer cells. These results suggest that wild-type mastic gum oils from Cesme and Mordogan (MGEOs 1 and 2) are potential sources of beneficial products and warrant further investigation.

TLC-Based Bioassay to Isolate Kairomones from Tea Tree Essential Oil That Attract Male Mediterranean Fruit Flies, Ceratitis capitata (Wiedemann).

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) poses a major threat to fruit and vegetable production in the United States and throughout the world. New attractants and detection methods could improve control strategies for this invasive pest. In this study, we developed a method that combined thin-layer chromatography (TLC) of tea tree essential oil (TTO) (Melaleuca alternifolia) with short-range bioassays to isolate attractive kairomones for male C. capitata. After development, the TLC chromatogram indicated that TTO separated into five major spots, designated as zones 1 to 5. When the TLC plate was exposed to flies, zones 1 and 3 were strongly attractive to male C. capitata. To confirm activity, the developed TLC plate was cut into five zones which were then tested in short-range bioassays. Again, flies were observed to aggregate around zones 1 and 3, which corresponded with Rf values of 0.93 and 0.59. In addition, zones 1 to 5 were separated using preparative-TLC, and olfactory responses to volatile emissions from the five fractions were quantified by electroantennography (EAG). Highest amplitude EAG responses were recorded with fractions 1 and 3, further supporting the bioactivity of these samples. In conclusion, a TLC-based bioassay system can provide an effective, rapid screening protocol for initial isolation of insect kairomones from complex mixtures such as essential oils or plant extracts. Further analysis of TTO fractions 1 and 3 is needed to identify the specific constituents attractive to male C. capitata.

Chemical composition of the essential oil and n-hexane extract of Stachys tmolea subsp. Tmolea Boiss., an endemic species of Turkey, and their mosquitocidal activity against dengue vector Aesdes aegypti.

Stachys tmolea subsp. tmolea Boiss. is endemic to Turkey and is a species of the genus Stachys L. which is one of the largest genera of the family Lamiaceae with about 300 species. The aims of this study were to examine the chemical composition of the essential oil and n-hexane extract of S. tmolea subsp. tmolea as natural sources of insecticidal activity against the dengue vector, Aedes aegypti. Analysis of the essential oil by GC-FID and gas chromatography-mass spectrometry (GC-MS) systems identified hexahydrofarnesyl acetone (15%), viridiflorol (10%), hexadecanoic acid (7%) and 9-geranyl-p-cymene (6%) as major components. The volatile components of the n-hexane extract were extracted using headspace solid-phase microextraction (HS-SPME) and were analyzed using GC-MS. The principal constituents were 3,4-dimethyl decane (16%), 3-methyl-3-pentanol (15%), 2-methyl-2-pentanol (12%), 1,4-bis (1,1-dimethylethyl) benzene (12%), heptanal (10%), acetic acid (6%) and decane (4%). Bioassay of the n-hexane extract, at 5 µg/mosquito, produced 90% mortality against adult Ae. aegypti while the S. tmolea essential oil demonstrated 13% mortality. No larvicidal activity was observed both in essential oil and n-hexane extract. Further studies are needed to assess the adulticidal activity of the responsible compounds in the crude extract.

Rhanterium epapposum Oliv. essential oil: Chemical composition and antimicrobial, insect-repellent and anticholinesterase activities.

The essential oil (EO) of the aerial parts of Rhanterium epapposum Oliv. (Asteraceae), was obtained by hydrodistillation. The oil was subsequently analyzed by both GC-FID and GC-MS, simultaneously. Forty-five components representing 99.2% of the oil composition were identified. The most abundant compounds were camphene (38.5%), myrcene (17.5%), limonene (10.1%) and α-pinene (8.7%). Referring to the ethnobotanical utilization, an insecticidal assay was performed, where the oil repelled the yellow fever mosquito Aedes aegypti L. at a minimum effective dose (MED of 0.035 ± 0.010 mg/cm2) compared to the positive control DEET (MED of 0.015 ± 0.004 mg/cm2). Additionally, the in vitro antimicrobial activity against a panel of pathogens was determined using a microdilution method. The acetyl- and butyrylcholine esterase inhibitory activities were measured using the colorimetric Ellman method. The bioassay results showed that the oil was rather moderate in antimicrobial and cholinesterase inhibitions when compared to the standard compounds.

Assessing the anticancer effects associated with food products and/or nutraceuticals using in vitro and in vivo preclinical development-related pharmacological tests.

This review is part of a special issue entitled "Role of dietary pattern, foods, nutrients and nutraceuticals in supporting cancer prevention and treatment" and describes a pharmacological strategy to determine the potential contribution of food-related components as anticancer agents against established cancer. Therefore, this review does not relate to chemoprevention, which is analysed in several other reviews in the current special issue, but rather focuses on the following: i) the biological events that currently represent barriers against the treatment of certain types of cancers, primarily metastatic cancers; ii) the in vitro and in vivo pharmacological pre-clinical tests that can be used to analyse the potential anticancer effects of food-related components; and iii) several examples of food-related components with anticancer effects. This review does not represent a catalogue-based listing of food-related components with more or less anticancer activity. By contrast, this review proposes an original pharmacological strategy that researchers can use to analyse the potential anticancer activity of any food-related component-e.g., by considering the crucial characteristics of cancer biological aggressiveness. This review also highlights that cancer patients undergoing chemotherapy should restrict the use of "food complements" without supervision by a medical nutritionist. By contrast, an equilibrated diet that includes the food-related components listed herein would be beneficial for cancer patients who are not undergoing chemotherapy.

Repellency of the Origanum onites L. essential oil and constituents to the lone star tick and yellow fever mosquito.

The oregano, Origanum onites L., essential oil (EO) was tested in laboratory behavioural bioassays for repellent activity against Amblyomma americanum (L.) and Aedes aegypti (L.). The O. onites EO was characterised using GC-FID and GC-MS. Carvacrol (75.70%), linalool (9.0%), p-cymene (4.33%) and thymol (1.9%) were the most abundant compounds. At a concentration of 0.413 mg oil/cm2 of filter paper, O. onites EO repelled 100% of the ticks tested and at 0.103 mg oil/cm2 of filter paper, 66.7% of the ticks were repelled. At 0.075 mg oil/cm2 filter paper, thymol repelled 66.7% of the ticks compared to 28.7% by carvacrol at that same concentration. Against Ae. aegypti, O. onites EO was repellent at the minimum effective dosage (MED) of 0.011 (±0.00) mg/cm2 in the cloth patch assay compared to the reference control, N,N-dimethyl-3-methylbenzamide (DEET) with a MED = 0.007 ± (0.003) mg/cm2.

Lantana montevidensis Essential Oil: Chemical Composition and Mosquito Repellent Activity against Aedes aegypti.

The essential oil (EO) of Lantana montevidensis (Spreng.) Briq. (L. sellowiana Link & Otto) was investigated for its chemical composition and mosquito repellent activity. The essential oil obtained by hydrodistillation of aerial plant parts was analyzed by GC-FID and GC-MS. The major constituents were p-elemene (22.0%), ß-caryophyllene (20.1%), and germacrene D (9.4%). Sesquiterpene hydrocarbons were present.in considerable quantities (78.9%) in the L. montevidensis EO, followed by oxygenated sesquiterpenes (8.9%), monoterpene hydrocarbons (7.7%), oxygenated monoterpenes (1.9%), diterpenes (1.2%) and other compounds (0.2%). The oil of L. montevidensis was repellent with a minimum effective dosage (MED) of 0.021 ± 0.013 mg/cm(2) as compared with that of the positive control N,N-diethyl-3-methylbenzamide (DEET) with a MED of 0.006 : 0.001 mg/cm(2)) against Aedes aegypti L. The major compound ß-elemene was tested individually for its repellency and had a MED value of 0.23 ? 0.14 mg/cm2 (DEET was 0.008 ? 0.001 mg/cm2). This is the first report on the repellent activity of L. montevidensis EO and P-elemene using human-based in vivo assays against Ae. aegypti.

Chemical Composition, Antioxidant, Antimicrobial and Insecticidal Activities of Essential Oil from a Moroccan Endemic Plant: Bubonium imbricatum.

The chemical composition, antioxidant, antimicrobial and insecticidal properties of essential oil obtained by hydro-distillation from Bubonium imbricatum Cav. have been investigated. The essential oil of aerial parts was analyzed by GC-FID and GC-MS. A total of 63 compounds were identified representing more than 82% of the oil. The major components were cis-chrysanthenyl acetate (31.2%) and thymol isobutyrate (3.4%). The antioxidant activity was evaluated by the DPPH and reducing power test. The data showed moderate activity compared with the reference compounds. Our results showed strong activity of the investigated oil against all tested microorganisms. The highest antibacterial activity was observed against Bacillus subtilis (inhibition zone= 18 ± 0.21, MIC= 0.18 mg/mL). In general, Gram-positive bacteria were more susceptible than Gram-negative ones. Candida parapsilosis was the most sensitive among the Candida strains tested. LD50 and LD90 values were 33.1 and 53.1 ppm against 1-d-old larvae of Aedes aegypti L.

11-Hydroxy-2,4-cycloeudesmane from the Leaf Oil of Juglans regia and Evaluation of its Larvicidal Activity.

Leaves of Juglans regia L. collected from two different locations [Adana (A) and Ankara (B)] from Turkey were subjected to hydrodistillation in a Clevenger type apparatus to yield the essential oils (EOs). GC/MS and GC-FID analyses revealed that the A EO was rich in thymol (23.1%), while caryophyllene oxide (33.8%) was found as the main constituent of B EO. Both contained P-eudesmol (1.4% - 9.5 %), (E)-geranyl acetone (3.7% - 5.8%) and the eudesmane type constituent juglaterpene A (3.1% - 11.0%). Using a HP Innowax preparative capillary column connected to a preparative fraction collector, an unknown constituent, juglaterpene A (1, 1 l-hydroxy-2,4-cycloeudesmane), was isolated in a rapid one-step manner with > 94.0% purity. Structure determination was accomplished from ID- and 2D-NMR spectroscopic data. Oil B demonstrated significant larvicidal activity against 1st instar Aedes aegypti L.

Chemical Composition of Fruit Essential Oil of Endemic Malabaila pastinacifolia.

The water distilled essential oil (EO) from the fruits of Malabaila pastinacifolia Boiss & Balansa (Apiaceae), an endemic species from Turkey, was analyzed using GC-FID and GC-MS systems. The analysis revealed 38 compounds accounting for 97.6% of the EO. Hexyl butyrate (47.2 %), hexyl hexanoate (22.7%) and a-terpinyl acetate (11.1 %) were found as the main constitutes. This is the first report on the EO composition of M pastinacifolia.

Essential Oil Composition of Pimpinella cypria and its Insecticidal, Cytotoxic, and Antimicrobial Activity.

A water-distilled essential oil (E) from the aerial parts of Pimpinella cypria Boiss. (Apiaceae), an endemic species in northern Cyprus, was analyzed by GC- FID and GC-MS. Forty-five compounds were identified in the oil, which comprised 81.7% of the total composition. The compound classes in the oil were oxygenated sesquiterpenes (33.9%), sesquiterpenes (22.0%), monoterpenes (11.4%), oxygenated monoterpenes (2.6%), and phenylpropanoids (7.5%). The main components of the oil were (Z)-ß-farnesene (6.0%), spathulenol (5.9%), ar-curcumene (4.3%), and 1,5-epoxy-salvial(4)14-ene (3.8%). The P. cypria EO deterred yellow fever mosquitoes (Aedes aegypti) from biting at a concentration of 10 µg/cm2 in in vitro bioassays. The oil was tested for repellency in assays using human volunteers. The oil had a minimum effective dosage (MED) for repellency of 47 ± 41 µg/cm² against Ae. aegypti, which was less efficacious than the positive control NN-diethyl-3-methylbenzamide (DEET). In larval bioassays, P. cypria EO showed an LC50 value of 28.3 ppm against 1st instar Ae. aegypti larvae. P. cypria EO demonstrated dose dependent repellency against nymphs of the lone star tick, Amblyomma americanum. Between 45.0% and 85.0% repellency was observed at concentrations ranging from 26 to 208 µg/cm². However, P. cypria EO was less effective compared with DEET in the tick bioassays. Cytotoxicity assays showed that the P. cypria EO did not exhibit significant effects up to the maximum treatment concentration of 50 µg/mL on HEK293, PC3, U87MG, and MCF cells. P. cypria EO also demonstrated moderate antimicrobial activity against Gram-negative and -positive bacteria with MICs ranging from 15.6 to 62.5 µg/mL, except for Candida albicans, which showed the same MIC value of 7.8 µg/mL as the positive control, flucytosine. This is the first report on the chemical composition of P. cypria EO and its insecticidal, toxicant, cytotoxic, and antimicrobial activity.

Chemical Composition and Biting Deterrent Activity of Essential Oil of Tagetes patula (Marigold) against Aedes aegypti.

The hydrodistilled leaf essential oil (EO) of Tagetes patula L. was analyzed by GC-FID and GC-MS. The main components of the oil were characterized as caryophyllene oxide (18.4%), p-caryophyllene (18.0%) and spathulenol (9.1%). The EO was screened for its biting deterrent activity against Aedes aegypti L. using the in vitro K&D module system. T. patula EO exhibited good biting deterrent activity. The results suggest that these sesquiterpenes may contribute to biting deterrent activity, but the role of minor components cannot be excluded. T. patula EO also showed 100, 90 and 10% mortality at dosages of 125, 62.5 and 31.25 ppm, respectively, in I-day-old larvae of Ae. aegypt.

Phoenix dactylifera L. spathe essential oil: chemical composition and repellent activity against the yellow fever mosquito.

Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dactylifera was obtained by hydrodistillation from the spathe, a specialized leaf structure that surrounds the pollinating organs of the palm. The oil was subsequently analyzed by GC-FID and GC-MS. The oil showed promising repellent activity against yellow fever mosquito - Aedes aegypti. Sixteen components were characterized, constituting 99% of the oil. The main components were 3,4-dimethoxytoluene (73.5%), 2,4-dimethoxytoluene (9.5%), ß-caryophyllene (5.5%), p-cresyl methyl ether (3.8%), and caryophyllene oxide (2.4%). The minimum effective dosage (MED) for repellency for the P. dactylifera oil was 0.051mg/cm(2), which had moderately lower potency compared to reference standard N,N-diethyl-3-methylbenzamide, DEET (0.018mg/cm(2)) in the "cloth patch assay". The five major compounds were individually assayed for repellency to determine to what extent each is responsible for repellency from the oil. 3,4-Dimethoxytoluene and 2,4-dimethoxytoluene showed the best repellent activity with the same MED value of 0.063mg/cm(2), respectively. The results indicate that these two constituents which comprise a large proportion of the P. dactylifera oil (83%) are likely responsible for the observed repellent activity. In this aspect, the P. dactylifera spathe oil is a sustainable, promising new source of natural repellents.

Synthesis and biological activity of substituted urea and thiourea derivatives containing 1,2,4-triazole moieties.

A series of novel thiourea and urea derivatives containing 1,2,4-triazole moieties were synthesized and evaluated for their antifungal and larvicidal activity. Triazole derivatives 3a-e and 4a-e were synthesized by reacting thiocarbohydrazide with thiourea and urea compounds 1a-e and 2a-e, respectively, in a 130-140 °C oil bath. The proposed structures of all the synthesized compounds were confirmed using elemental analysis, UV, IR, 1H-NMR and mass spectroscopy. All compounds were evaluated for antifungal activity against plant pathogens, larvicidal and biting deterrent activity against the mosquito Aedes aegypti L. and in vitro cytotoxicity and anti-inflammatory activity against some human cell lines. Phomopis species were the most sensitive fungi to these compounds. Compounds 1b, 1c, 3a and 4e demonstrated selectively good activity against Phomopis obscurans and only 1b and 4e showed a similar level of activity against P. viticola. Compound 3d, with a LD50 value of 67.9 ppm, followed by 1c (LD50 = 118.8 ppm) and 3e (LD50 = 165.6 ppm), showed the highest toxicity against Aedes aegypti larvae. Four of these compounds showed biting deterrent activity greater than solvent control, with the highest activity being seen for 1c, with a proportion not biting (PNB) value of 0.75, followed by 1e, 2b and 1a. No cytotoxicity was observed against the tested human cancer cell lines. No anti-inflammatory activity was observed against NF-kB dependent transcription induced by phorbol myristate acetate (PMA) in human chondrosarcoma cells.

Biting deterrence, repellency, and larvicidal activity of Ruta chalepensis (Sapindales: Rutaceae) essential oil and its major individual constituents against mosquitoes.

The essential oil from aerial parts of Ruta chalepensis L. (Sapindales: Rutaceae) was obtained by hydrodistillation, and its chemical profile was identified using gas chromatography and gas chromatography-mass spectrometry. Compounds, 2-undecanone (43.2%), 2-nonanone (27.9%), and 2-nonyl acetate (10.6%) were the major constituents of the oil. Biting deterrent activity of R. chalepensis essential oil at 10 and 50 microg/cm2, 2-undecanone at 8.5 microg/cm2, 2-nonanone at 9 microg/cm2, and 2-nonyl acetate at 9.3 microg/cm2 was similar to DEET (N, N-diethyl-meta-toluamide) at 4.8 microg/cm2, against Aedes aegypti L. Biting deterrent activity of R. chalepensis oil at 50 microg/cm2 against Anopheles quadrimaculatus Say was statistically similar to DEET at 4.8 microg/cm2, whereas the activity was lower in the other compounds tested. In cloth patch assay, R. chalepensis essential oil was effective at 187 microg/cm2, whereas 2-undecanone was effective at 108.9 microg/cm2 against Ae. aegypti. In larval bioassays, 2-undecanone showed similar toxicity whereas toxicity of R. chalepensis essential oil and 2-nonanone was higher at 24-h posttreatment at the LD50 in An. quadrimaculatus than Ae. aegypti. This study revealed that R. chalepensis essential oil and its major compounds were active biting deterrents against Ae. aegypti at higher application rates whereas only the essential oil showed activity similar to DEET against An. quadrimaculatus. 2-undecanone was the most active compound in in vivo repellency bioassay against Ae. aegypti. Chemical composition of R. chalepensis essential oil varies because of plant production and harvest practices, and the activity level of the essential oil may depend on the source of the sample.

One-step multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak by preparative capillary gas chromatography with characterization by spectroscopic and spectrometric techniques and evaluation of biological activity.

Gas chromatographic analysis revealed that the oil of Crinitaria tatarica was rich in sabinene (32.1%), ß-pinene (8.8%), and two unknown (M+200) compounds (I) and (II) (21.4% and 3.4%). One-step multiple fractionation of the oil and separation of two unknown constituents were performed using preparative capillary gas chromatography connected to preparative fraction collector system. This combination allowed separation and recover of sufficient quantities of two unknown compounds with high purity from complex oil matrix. Separation conditions (column temperature, cooling temperature, flow rate, injection volume, cut time) were optimized to achieve the best isolation and successful collection. The target compounds were separated from the oil using a HP Innowax (Walt & Jennings Scientific, Wilmington, DE, USA) preparative capillary column in rapid one-step manner with 95.0% purity. Trapping of the isolated compounds in collector system was facilitated by cooling with liquid nitrogen. Structure determination was accomplished by spectral analysis including ultraviolet, nuclear magnetic rezonance, and high-resolution electrospray ionization mass spectrometry. Z- (I) and E-artemidin (II) were isolated for the first time from this species. Crinitaria tatarica oil and Z- (I) and E-artemidin (II) were evaluated for biological activity.

Essential oil composition of five collections of Achillea biebersteinii from central Turkey and their antifungal and insecticidal activity.

The composition of the essential oils hydrodistilled from the aerial parts of five Achillea biebersteinii Afan samples, collected in central Turkey from Konya, Isparta and Ankara, were analyzed both by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Eighty-four components were identified, representing 87 to 99% of the total oil composition. The identified major components were 1,8-cineole (9-37%), camphor (16-30%) and p-cymene (1-27%). Two samples differed in piperitone (11%) and ascaridol (4%) content. The five A. biebersteinii essential oils were subsequently evaluated for their antifungal activity against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides using the direct overlay bioautography assay. The essential oils showed no antifungal activity at 80 and 160 microg/spot. In addition, A. biebersteinii oils and their major compounds were subsequently investigated against Aedes aegypti first instar larvae in a high throughput bioassay. Among the oils, only one sample from Ankara showed a notable larvacidal effect on Ae. aegypti larvae. The major compounds, 1,8-cineole, camphor and p-cymene, exhibited low mosquito larval activity, and thus the minor compounds are probably responsible for the observed activity against Ae. aegypti larvae. The oils showed weak activity against adult Ae. aegypti.

Biological activity of peanut (Arachis hypogaea) phytoalexins and selected natural and synthetic Stilbenoids.

The peanut plant (Arachis hypogaea L.), when infected by a microbial pathogen, is capable of producing stilbene-derived compounds that are considered antifungal phytoalexins. In addition, the potential health benefits of other stilbenoids from peanuts, including resveratrol and pterostilbene, have been acknowledged by several investigators. Despite considerable progress in peanut research, relatively little is known about the biological activity of the stilbenoid phytoalexins. This study investigated the activities of some of these compounds in a broad spectrum of biological assays. Since peanut stilbenoids appear to play roles in plant defense mechanisms, they were evaluated for their effects on economically important plant pathogenic fungi of the genera Colletotrichum, Botrytis, Fusarium, and Phomopsis. We further investigated these peanut phytoalexins, together with some related natural and synthetic stilbenoids (a total of 24 compounds) in a panel of bioassays to determine their anti-inflammatory, cytotoxic, and antioxidant activities in mammalian cells. Several of these compounds were also evaluated as mammalian opioid receptor competitive antagonists. Assays for adult mosquito and larvae toxicity were also performed. The results of these studies reveal that peanut stilbenoids, as well as related natural and synthetic stilbene derivatives, display a diverse range of biological activities.

Eupatorium capillifolium essential oil: chemical composition, antifungal activity, and insecticidal activity.

Natural plant extracts often contain compounds that are useful in pest management applications. The essential oil of Eupatorium capillifolium (dog-fennel) was investigated for antifungal and insecticidal activities. Essential oil obtained by hydrodistillation of aerial parts was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The major components were determined to be thymol methyl ether (=methyl thymol) (36.3%), 2,5-dimethoxy-p-cymene (20.8%) and myrcene (15.7%). Antifungal activity of the essential oil was weak against the plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides in direct bioautography assay. The E. capillifolium oil showed promising repellent activity against the yellow fever mosquito Aedes aegypti, whereas the oil exhibited moderate activity against the mosquito's first instar larvae in a high throughput bioassay. Topical applications of the oil showed no activity against the blood-feeding female adults of A. aegypti. Eupatorium capillifolium essential oil showed a linear dose response between adult lace bug (Stephanitis pyrioides) mortality and increasing oil concentration in an adulticidal activity bioassay. The dog-fennel oil was more potent than the conventional insecticide malathion. In conclusion, these combined results showed Eupatorium capillifolium oil is a promising novel source of a biological insecticide with multiple modes of action.