David E. Wedge

Gas chromatographic-mass spectrometric analysis of volatiles obtained by four different techniques from Salvia rosifolia Sm., and evaluation for biological activity

Four different isolation techniques, conventional hydrodistillation (HD), microwave-assisted hydrodistillation (MWHD), microdistillation (MD) and micro-steam distillation-solid-phase microextraction (MSD-SPME), have been used to analyze the volatile constituents from the aerial parts of Salvia rosifolia Sm. by gas chromatography and gas chromatography coupled to mass spectrometry. HD and MWHD techniques produced quantitatively (yield, 0.39% and 0.40%) and qualitatively (aromatic profile) similar essential oils. alpha-Pinene (15.7-34.8%), 1,8-cineole (16.6-25.1%), beta-pinene (6.7-13.5%), beta-caryophyllene (1.4-5.0%) and caryophyllene oxide (1.4-4.4%) were identified as major constituents of this Turkish endemic species. Besides, the hydrodistilled oil of S. rosifolia was evaluated for antibacterial, antifungal, anticancer, antioxidant and cytotoxic activities. The hydrodistilled oil of S. rosifolia showed antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) with a MIC value of 125microg/mL. Other human pathogenic microorganisms (Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Salmonella typhimurium, Staphylococcus epidermidis, Candida albicans) were also inhibited within a moderate range (MIC=125-1000microg/mL). Antifungal activity of the oil was also observed against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides. No cytotoxicity was observed for S. rosifolia oil up to 25mg/mL against malignant melanoma, epidermal, ductal and ovary carcinoma.

Essential oils of Cupressus funebris, Juniperus communis, and J. chinensis (Cupressaceae) as repellents against ticks (Acari: Ixodidae) and mosquitoes (Diptera: Culicidae) and as toxicants against mosquitoes

ABSTRACT: Juniperus communis leaf oil, J. chinensis wood oil, and Cupressus funebris wood oil (Cupressaceae) from China were analyzed by gas chromatography and gas chromatography-mass spectrometry We identified 104 compounds, representing 66.8–95.5% of the oils. The major components were: &agr;-pinene (27.0%), &agr;-terpinene (14.0%), and linalool (10.9%) for J. communis; cuparene (11.3%) and &dgr;-cadinene (7.8%) for J. chinensis; and &agr;-cedrene (16.9%), cedrol (7.6%), and &bgr;-cedrene (5.7%) for C. funebris. The essential oils of C. funebris, J. chinensis, and J. communis were evaluated for repellency against adult yellow fever mosquitoes, Aedes aegypti (L.), host-seeking nymphs of the lone star tick, Amblyomma americanum (L.), and the blacklegged tick, Ixodes scapularis Say, and for toxicity against Ae. aegypti larvae and adults, all in laboratory bioassays. All the oils were repellent to both species of ticks. The EC95 values of C. funebris, J. communis, and J. chinensis against A. americanum were 0.426, 0.508, and 0.917 mg oil/cm2 filter paper, respectively, compared to 0.683 mg deet/cm2 filter paper. All I. scapularis nymphs were repelled by 0.103 mg oil/cm2 filter paper of C. funebris oil. At 4 h after application, 0.827 mg oil/cm2 filter paper, C. funebris and J. chinensis oils repelled ≥80% of A. americanum nymphs. The oils of C. funebris and J. chinensis did not prevent female Ae. aegypti from biting at the highest dosage tested (1.500 mg/cm2). However, the oil of J. communis had a Minimum Effective Dosage (estimate of ED99) for repellency of 0.029 ± 0.018 mg/cm2; this oil was nearly as potent as deet. The oil of J. chinensis showed a mild ability to kill Ae. aegypti larvae, at 80 and 100% at 125 and 250 ppm, respectively.

Biting Deterrence, Repellency, and Larvicidal Activity of Ruta chalepensis (Sapindales: Rutaceae) Essential Oil and Its Major Individual Constituents Against Mosquitoes

ABSTRACT 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 µg/cm2, 2-undecanone at 8.5 µg/cm2, 2-nonanone at 9 µg/cm2, and 2-nonyl acetate at 9.3 µg/cm2 was similar to DEET (N, N-diethyl-meta-toluamide) at 4.8 µg/cm2, against Aedes aegypti L. Biting deterrent activity of R. chalepensis oil at 50 µg/cm2 against Anopheles quadrimaculatus Say was statistically similar to DEET at 4.8 µg/cm2, whereas the activity was lower in the other compounds tested. In cloth patch assay, R. chalepensis essential oil was effective at 187 µg/cm2, whereas 2-undecanone was effective at 108.9 µg/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.

Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

The antimicrobial properties of essential oils have been documented, and their use as “biocides” is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and cultivars were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. The antifungal and insecticidal activities of these oils were tested against Colletotrichum acutatum, C. fragariae, and C. gloeosporioides, and three insects, the azalea lace bug (Stephanitis pyrioides), the yellow fever mosquito (Aedes aegypti), and the red imported fire ant (Solenopsis invicta). Hedychium oils were rich in monoterpenes and sesquiterpenes, especially 1,8-cineole (0.1%–42%), linalool (<0.1%–56%), α-pinene (3%–17%), β-pinene (4%–31%), and (E)-nerolidol (0.1%–20%). Hedychium oils had no antifungal effect on C. gloeosporioides, C. fragariae, and C. acutatum, but most Hedychium oils effectively killed azalea lace bugs. The oils also show promise as an adult mosquito repellent, but they would make rather poor larvicides or adulticides for mosquito control. Hedychium oils acted either as a fire ant repellent or attractant, depending on plant genotype and oil concentration.

Comparative effects of eight varieties of blackberry on mutagenesis

Abstract Diets containing large amounts of fruits and vegetables are known to decrease the probability of developing cancer. The chemical composition of fruits can vary with their genetic characteristics and the environmental conditions under which they are cultivated. Because of this variability, different varieties of the same fruit could be expected to have different effects on processes leading to carcinogenesis. Blackberries have been shown to have anti-carcinogenic potential. Since somatic mutations play a major role in the initiation and progression of cancer, we have compared eight varieties of blackberry grown under the same conditions for their abilities to inhibit carcinogen-induced mutagenesis. Using the Ames assay, we have measured the effects of each of the eight varieties on: 1) mutation induction by 2-amino anthracene (2AA), 2) mutation induction by methyl methanesulfonate (MMS) and 3) cell survival. All varieties were found to strongly suppress 2AA mutagenesis, but have minimal effect on MMS mutagenesis. Experiments were performed with berry juice and with homogenized berries. In addition, berries extracts were acidified to simulate changes which might be caused by the digestive process.

Antifungal properties of cyanobacteria and algae: ecological and agricultural implications

Scientific reports of fungi associated with marine algae date back to the late nineteenth century[1, 2]. Since then, many species of fungi have been identified from marine macroalgae [3]. As many as one-third of the described species of marine higher fungi and many species of lower fungi are associated with marine algae [4, 5]. Similarly, aquatic fungi are often found in association with freshwater algae and microscopic cyanobacteria [6]. While most reports are primarily taxonomic, the ecological nature of the interactions between these associations is diverse. Saprophytic fungi are common, and parasitic fungal species can seriously affect vast populations of macroalgae raised in commercial sea-farming enterprises [7].

DISCOVERY AND EVALUATION OF NATURAL PRODUCT-BASED FUNGICIDES FOR DISEASE CONTROL OF SMALL FRUITS

The continuing development of fungicide resistance in plant and human pathogens necessitates the discovery and development of new fungicides. Discovery and evaluation of natural product fungicides is largely dependent upon the availability of miniaturized antifungal bioassays. Essentials for natural product bioassays include sensitivity to microgram quantities, selectivity to determine optimum target pathogens, and adaptability assays should be relevant to potential pathogen target sites in the natural infection process of the host and applicable to the agrochemical industry. Bioassays should take advantage of current high-throughput technology available to evaluate dose-response relationships, commercial fungicides standards, modes of action, and structure activity studies. The focus of this chapter is the evaluation of natural product based fungicides for agriculture and we will provide a review of bioautography prescreens and microtiter assays (secondary assays). Also presented is more detailed information on newer techniques such as the detached leaf assays for evaluating fungicides against strawberry anthracnose (Colletotrichum spp.) and field plot trials for gray mold (Botrytis) and anthracnose control in strawberry. Since the early 1970s, agriculture worldwide has struggled with the evolution of pathogen resistance to disease control agents. Increased necessity for repeated chemical applications, development of pesticide cross-resistance, and disease resistance management strategies have characterized the use of agricultural chemicals to-date. As a consequence, producers are currently attempting to control agricultural pests with a decreasing arsenal of effective crop protection chemicals. In addition, the desire for safer pesticides with less environmental impact has become a major public concern. Particularly desirable is the discovery of novel pesticidal agents from new chemical classes that are able to operate using different modes of action and, consequently, against plant pathogens with resistance to currently used chemistries. In this regard, evaluating natural products and extracts as a source of new pesticides is one strategy for the discovery of new chemical moieties that have not previously been created by synthetic chemists. to complex mixtures. Experimental accuracy and precision must be stable between assays over time. These

Chemical Composition and Biological Activity of Haplophyllum tuberculatum Juss. Essential Oil

Abstract: The essential oil of Haplophyllum tuberculatumwas prepared by hydrodistillation of the fresh flowering aerial parts of the plant collected from Saudi Arabia. The oil was subsequently analyzed by GC and GC-MS. Thirty seven compounds, accounting for 96.4 % of the oil composition were identified. The major components were trans-p-menth-2-en-1-ol (19.2 %), cis-p-menth-2-en-1-ol (13.2 %), myrcene (10.1 %), δ-3- carene (8.8 %), β-phellandrene (6.9 %), limonene (6.6 %) and cis-piperitol (6.4 %). The antimicrobial activity of the essential oil was determined using the broth microdilution method against various human pathogens, where a relatively low inhibitory range was observed (MIC 1 mg/mL). Furthermore, the oil was evaluated for its 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 oil showed no antifungal activity at 80 and 160 µg/spot concentrations compared to commercial antifungal standards. The oil was also investigated for its insecticidal and repellent activity against Aedes aegypti. The oil was repellent to the yellow fever mosquito Ae. aegypti using the “cloth patch assay” down to a concentration of 0.074 mg/cm2; however, the oil had low toxicity against first instar larvae and adults of Ae. aegypti in a high throughput larval bioassay and adult topical assay. Additionally, enzyme activity was measured using the spectrophotometric Ellman method. The oil showed weakly acetylcholinesterase (AChE) inhibitory activity at the tested concentration, compared to standard substances, whereas no inhibition on butyrylcholinesterase (BuChE) activity was observed.

Preliminary investigation of Origanum onites essential oil by overpressured layer chromatography and BioArena

Origanum species are aromatic and fragrant plants which are well known for their use as a food spice. Since ancient times Origanum species have also been used in traditional medicine as herbal tea. Aromatic oregano water is consumed for gastrointestinal disorders, to reduce blood cholesterol and glucose levels, and to combat cancer [1]. The antibacterial effect of Origanum onites oil and its major components (carvacrol, thymol, and linalool) have been studied by use of the BioArena system [2, 3] combined with infusion OPLC separation [4, 5].

Fungicide Resistance Profiles for 13 Botrytis cinerea Isolates from Strawberry in Southeastern Louisiana

Fungicidal sprays are widely used for control of Botrytis fruit rot; however, the pathogen often develops resistance to frequently used fungicides. A 96-well plate micro-dilution broth bioassay developed for fungicide discovery was used to provide strawberry growers with a rapid assessment of the fungicide sensitivity of Botrytis isolates against 16 fungicides. Three sensitivity phenotypes were identified: benzimidazole and dicarboximide resistant, benzimidazole resistant and dicarboximide sensitive, and an intermediate response to both fungicides. Codon at position 198 in the β-tubulin gene confirmed benomyl resistance. This bioassay rapidly identifies fungicide resistance and allows growers to quickly adjust their disease management strategy.