Biopesticidal value of selected essential oils against pathogenic fungus, termites, and nematodes

The biopesticidal potential of six plant-derived essential oils (mint [Mentha arvensis], ajwain [Carum capticum], lemongrass [Cymbopogon citrates], clove [Eugenia caryophyllata], cedarwood [Cedrus deodara], and eucalyptus [Eucalyptus globulas]) was evaluated against Odontotermes obesus (termites), Fusarium oxysporum (plant pathogenic fungi), and Meloidogyne incognita (nematodes). In the case of termites, a “no-choice” bioassay revealed that the mint oil gave the best results (100% mortality in 30 min with 10% oil and in 10 h with 0.12% oil) followed by the lemongrass and ajwain oils. The disc diffusion method was adopted to test the anti-fungal activity of the essential oils and it was found that the clove oil gave the maximum inhibition measured in terms of the average inhibition zone diameter (5.3 ± 0.2 cm with 10% oil and 6.6 ± 0.9 cm with 20% oil), followed by the ajwain oil. To check the anti-nematicidal activity of the essential oil, in-vitro growth chamber experiments revealed that eucalyptus oil was the most efficient (100% mortality in 6 h with 1000 ??l l⁻¹ oil and in 30 h with 125 ??l l⁻¹ oil), followed by the ajwain oil. The use of the crude oils at low concentrations provided satisfactory results at the laboratory level against these pathogens, and needs further evaluation in field trials.     

Antifungal properties of essential oil and crude extracts of Hypericum linarioides Bosse

The chemical composition of the essential oil isolated from the aerial parts of Hypericum linarioides Bosse by hydrodistillation was analysed by GC–MS. It was determined that 74 compounds, which represent 84.1% of total oil, were present in the oil. The oil contains mainly δ-cadinene (6.9%), (Z)-β-farnesene (5.2%), γ-muurolene (5.5%), spathulenol (4.8%), hexahydrofarnesyl acetone (4.5%) and α-selinene (4.0%). The oil was also characterized by high content of sesquiterpenes (64.2% of total oil). The oil was tested for antifungal activity using mycelial growth inhibition assays (in vitro) against 11 agricultural pathogenic fungi, which consisted of six Fusarium species (Fusarium acuminatum, Fusarium culmorum, Fusarium equiseti, Fusarium oxysporum, Fusarium sambucinum and Fusarium solani) and three anastomosis groups of Rhizoctonia solani (AG-5, AG-9 and AG-11), Alternaria solani and Verticillium albo-atrum. The oil of H. linarioides showed antifungal activity against AG-9 and V. albo-atrum. In addition, petroleum ether, chloroform, acetone and methanol extracts of H. linarioides were tested against species of 11 fungi. The extracts showed moderate inhibition effects on the growth of A. solani, F. culmorum, F. equiseti and all anastomosis groups of R. solani.     

Dietary supplementation of pyrroloquinoline quinone disodium protects against oxidative stress and liver damage in laying hens fed an oxidized sunflower oil-added diet

The protective effects of dietary pyrroloquinoline quinone disodium (PQQ.Na₂) supplementation against oxidized sunflower oil-induced oxidative stress and liver injury in laying hens were examined. Three hundred and sixty 53-week-old Hy-Line Gray laying hens were randomly allocated into one of the five dietary treatments. The treatments included: (1) a diet containing 2% fresh sunflower oil; (2) a diet containing 2% thermally oxidized sunflower oil; (3) an oxidized sunflower oil diet with 100 mg/kg of added vitamin E; (4) an oxidized sunflower oil diet with 0.08 mg/kg of PQQ.Na₂; and (5) an oxidized sunflower oil diet with 0.12 mg/kg of PQQ.Na₂. Birds fed the oxidized sunflower oil diet showed a lower feed intake compared to birds fed the fresh oil diet or oxidized oil diet supplemented with vitamin E (P=0.009). Exposure to oxidized sunflower oil increased plasma malondialdehyde (P<0.001), hepatic reactive oxygen species (P<0.05) and carbonyl group levels (P<0.001), but decreased plasma glutathione levels (P=0.006) in laying hens. These unfavorable changes induced by the oxidized sunflower oil diet were modulated by dietary vitamin E or PQQ.Na₂ supplementation to levels comparable to the fresh oil group. Dietary supplementation with PQQ.Na₂ or vitamin E increased the activities of total superoxide dismutase and glutathione peroxidase in plasma and the liver, when compared with the oxidized sunflower oil group (P<0.05). PQQ.Na₂ or vitamin E diminished the oxidized sunflower oil diet induced elevation of liver weight (P=0.026), liver to BW ratio (P=0.001) and plasma activities of alanine aminotransferase (P=0.001) and aspartate aminotransferase (P<0.001) and maintained these indices at the similar levels to the fresh oil diet. Furthermore, oxidized sunflower oil increased hepatic DNA tail length (P<0.05) and tail moment (P<0.05) compared with the fresh oil group. Dietary supplementation of PQQ.Na₂ or vitamin E decreased the oxidized oil diet induced DNA tail length and tail moment to the basal levels in fresh oil diet. These results indicate that PQQ.Na₂ is a potential antioxidant and is as effective against oxidized oil-related liver injury in laying hens as vitamin E. The protective effects of PQQ.Na₂ against liver damage induced by oxidized oil may be partially due to its role in the scavenging of free radicals, inhibiting of lipid peroxidation and enhancing of antioxidant defense systems.     

Identification and Association Analysis of Castor Bean Orthologous Candidate Gene-Based Markers for High Oil Content in Jatropha curcas

Jatropha (Jatropha curcas) and castor bean (Ricinus communis) possess several taxonomic similarities, and their seeds contain a high proportion of oil (up to 40%) which has been used in various industrial products, including diesel oil. Thirty-two candidate genes responsible for fatty acid biosynthesis were identified in the castor bean genome sequence. Testing of 48 primer pairs from candidate gene regions, including 12 SSRs from castor bean on 54 genotypes of J. curcas, 65% amplified successfully on Jatropha out of which 20% showed polymorphisms. Jatropha genotypes, categorized for oil content, were used in association analysis of candidate gene regions with high oil content. One marker–trait association for the oil trait was identified. Stearoyl desaturase amplicon (700 bp) consisting of intron and exon (P?=?0.00013) showed association with high oil content in Jatropha genotypes. Sequencing of the 1.3-kb amplicon, including the 700-bp fragment of stearoyl desaturase, which had shown association with the high oil content, revealed SNPs in the exonic region. The SNPs resulted in substitution of leucine with glutamine in the open reading frame of stearoyl desaturase of low oil content genotypes. The molecular marker is expected to be useful in marker-assisted breeding of high oil content genotypes in Jatropha.     

The evolution and loss of oil-offering flowers: new insights from dated phylogenies for angiosperms and bees

The interactions between bees that depend on floral oil for their larvae and flowers that offer oil involve an intricate mix of obligate and facultative mutualisms. Using recent phylogenies, new data on oil-offering Cucurbitaceae, and molecular-dating, we ask when and how often oil-offering flowers and oil-foraging bees evolved, and how frequently these traits were lost in the cause of evolution. Local phylogenies and an angiosperm-wide tree show that oil flowers evolved at least 28 times and that floral oil was lost at least 36–40 times. The oldest oil flower systems evolved shortly after the K/T boundary independently in American Malpighiaceae, tropical African Cucurbitaceae and Laurasian Lysimachia (Myrsinaceae); the ages of the South African oil flower/oil bee systems are less clear. Youngest oil flower clades include Calceolaria (Calceolariaceae), Iridaceae, Krameria (Krameriaceae) and numerous Orchidaceae, many just a few million years old. In bees, oil foraging evolved minimally seven times and dates back to at least 56 Ma (Ctenoplectra) and 53 Ma (Macropis). The co-occurrence of older and younger oil-offering clades in three of the four geographical regions (but not the Holarctic) implies that oil-foraging bees acquired additional oil hosts over evolutionary time. Such niche-broadening probably started with exploratory visits to flowers resembling oil hosts in scent or colour, as suggested by several cases of Muellerian or Batesian mimicry involving oil flowers.     

Insecticidal activity and chemical composition of the essential oil of Artemisia vestita from China against Sitophilus zeamais

In our screening program for new agrochemicals from local wild plants, essential oil of Artemisia vestita Wall (Asteraceae) was found to possess strong insecticidal activity against maize weevil, Sitophilus zeamais Motsch. Essential oil of aerial parts of A. vestita was obtained from hydrodistillation and was investigated by GC and GC–MS. The main components of essential oil were grandisol (40.29%), 1,8-cineol (14.88%) and camphor (11.37%). The essential oil of A. vestita possessed strong fumigant toxicity against S. zeamais adults with a LC₅₀ value of 13.42 mg/L air. The essential oil of A. vestita also showed contact toxicity against S. zeamais adults with a LD₅₀ value of 50.62 mg/adult.     

GC/MS analysis and potential synergistic effect of mandarin and marjoram oils on Helicobacter pylori

Helicobacter pylori can cause chronic gastritis, peptic ulcer, and gastric carcinoma. This study compares chemical composition and anti-H. pylori activity of mandarin leaves and marjoram herb essential oils, and their combined oil. GC/MS analysis of mandarin oil revealed six compounds (100% identified), mainly methyl-N-methyl anthranilate (89.93%), and 13 compounds (93.52% identified) of marjoram oil, mainly trans-sabinene hydrate (36.11%), terpinen-4-ol (17.97%), linalyl acetate (9.18%), and caryophyllene oxide (8.25%)). Marjoram oil (MIC = 11.40 µg/mL) demonstrated higher activity than mandarin oil (MIC = 31.25 µg/mL). The combined oil showed a synergistic effect at MIC of 1.95 µg/mL (same as clarithromycin). In-silico molecular docking on H. pylori urease, CagA, pharmacokinetic and toxicity studies were performed on major compounds from both oils. The best scores were for caryophyllene oxide then linalyl acetate and methyl-N-methyl anthranilate. Compounds revealed high safety and desirable properties. The combined oil can be an excellent candidate to manage H. pylori.     

Mycoremediation of crude oil contaminated soil by specific fungi isolated from Dhahran in Saudi Arabia

Crude oil biodegrading microorganism considers the key role for environmental preserving. In this investigation, crude oil biodegrading fungal strains have been isolated in polluted soil of crude-oil at khurais oil ground in Kingdom of Saudi Arabia. Among of 22 fungal isolates, only three isolates reflected potential capability for oil degradation. These isolates were identified and submitted to GenBank as (A1) Aspergillus polyporicola (MT448790), (A2) Aspergillus spelaeus (MT448791) and (A3) Aspergillus niger (MT459302) through internal-transcribed spacer-regions (ITS1&ITS2) for sequencing in molecular marker. Comparing with controls, strain (A1) Aspergillus niger was superior for biodegradation ability (58%) comparing with Aspergillus polyporicola and Aspergillus spelaeus degrading were showed 47 and 51% respectively. Employed CO₂ evolution as indicator for petroleum oil biodegradation by the fungal isolates reflected that, Aspergillus niger emission highest CO2 (28.6%) comparing with Aspergillus spelaeus and Aspergillus polyporicola which showed 13% and 12.4% respectively. capability of Aspergillus sp. to tolerate and adapted oil pollutants with successful growth rate on them, indicated that it can be employed as mycoremediation agent for recovering restoring ecosystem when contaminated by crude oil.     

Insecticidal effects of Flourensia oolepis Blake (Asteraceae) essential oil

Flourensia oolepis Blake (Asteraceae) essential oil had a complex chemical composition with τ-muurolene (6.14%), santolinetriene (6.22%), 2-methylene-4,8,8-trimethyl-4-vinyl-bicyclo[5.2.0]nonane (10.15%), δ-cadinene (10.27%) and γ-gurjunene (20.69%) comprising more than 50% of the oil. This oil had repellent and toxic effects on Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) adults, acting as a contact toxin. Myzus persicae (Sulzer) (Homoptera: Aphididae) and Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) adults showed behavioral sensibility to this oil.     

Freeze-dried microalgae of Nannochloropsis oculata improve soybean oil's oxidative stability

Marine microalga Nannochloropsis oculata possesses nutrients valuable for human health. In this study, we added freeze-dried N. oculata powder to soybean oil and observed a remarkable inhibition in oil oxidation. The amount of microalgae powder added was positively correlated to the increase in oil stability. The addition of 5.0 % (w/w) microalgae powder increased the oil stability index (OSI) values of soybean oil more than twofold at the tested temperatures 120 and 130 °C. N. oculata contains high levels of both phenolic compounds and α-tocopherols that could be the contributors to such an increase of the OSI. Two methods were conducted to assay the active ingredients released from microalgae: one employed three solvent systems to extract the microalgae and the other was the soybean oil added with microalgae. Analyses of free radical scavenging and reducing power suggested that the phenolic compounds dominated the antioxidation activities in soybean oil when it was infused with the microalgae powder. Our results suggest that N. oculata could potentially be used as an additive in cooking oil to increase the shelf life and nutritional value of the oil and to reduce the production of free radicals from lipid oxidation when the oil is used at high-temperature cooking processes.     

Antifungal effects of citronella oil against Aspergillus niger ATCC 16404

Essential oils are aromatic oily liquids obtained from some aromatic plant materials. Certain essential oils such as citronella oil contain antifungal activity, but the antifungal effect is still unknown. In this study, we explored the antifungal effect of citronella oil with Aspergillus niger ATCC 16404. The antifungal activity of citronella oil on conidia of A. niger was determined by poisoned food technique, broth dilution method, and disc volatility method. Experimental results indicated that the citronella oil has strong antifungal activity: 0.125 (v/v) and 0.25 % (v/v) citronella oil inhibited the growth of 5?×?10⁵ spore/ml conidia separately for 7 and 28 days while 0.5 % (v/v) citronella oil could completely kill the conidia of 5?×?10⁵ spore/ml. Moreover, the fungicidal kinetic curves revealed that more than 90 % conidia (initial concentration is 5?×?10⁵ spore/ml) were killed in all the treatments with 0.125 to 2 % citronella oil after 24 h. Furthermore, with increase of citronella oil concentration and treatment time, the antifungal activity was increased correspondingly. The 0.5 % (v/v) concentration of citronella oil was a threshold to kill the conidia thoroughly. The surviving conidia treated with 0.5 to 2 % citronella oil decreased by an order of magnitude every day, and no fungus survived after 10 days. With light microscope, scanning electron microscope, and transmission electron microscope, we found that citronella oil could lead to irreversible alteration of the hyphae and conidia. Based on our observation, we hypothesized that the citronella oil destroyed the cell wall of the A. niger hyphae, passed through the cell membrane, penetrated into the cytoplasm, and acted on the main organelles. Subsequently, the hyphae was collapsed and squashed due to large cytoplasm loss, and the organelles were severely destroyed. Similarly, citronella oil could lead to the rupture of hard cell wall and then act on the sporoplasm to kill the conidia. Nevertheless, the citronella oil provides a potential of being a safe and environmentally friendly fungicide in the future.     

Sulphides and furanones from steam volatile oils of Allium fistulosum and Allium chinense

The constituents of the steam volatile oils from two kinds of Allium fistulosum, A. fistulosum var. caespitosum and A. chinense, have been investigated by GC and spectral techniques (IR, UV, GC/MS, ¹H NMR and ¹³C NMR). The compounds identified from the neutral fraction of each volatile oil included sulphides, thiolanes, alcohols, aldehydes, ketones, furanones and others. Among the sulphur compounds, dipropyl disulphide comprised ca 28% of A. fistulosum oil, ca 23% of A. fistulosum var. caespitosum oil and ca 30% of A. chinense oil. A. fistulosum oil was characterized by a large quantity of tridecan-2-one (ca 52%) and 2,3-dihydro-2-octyl-5-methylfuran-3-one (ca 16%). Also, a large amount of 2,3-dihydro-2-hexyl-5-methylfuran-3-one (ca 20%) was isolated from A. chinense oil.     

Absorption and translocation of lipidic substances by plants

Young seedlings ofZea mays L. andCucurbita pepo L. were grown in water culture with a layer of oil (linum or olive oil) or liquid paraffin. The seedlings transport oil and parafin into the top and in the young root.Cucurbita seedlings proved to be very sensitive and died within few days.Zea proved to be resistant. InZea this transport of oil was found to be related to the age of the seedlings and the zone of the root in contact with oil. The oil was localised in the cell walls of different tissues of root and top, in the intercellular spaces of cortex and pith and in the xylem vessels.     

Effect of Ferula assafoetida essential oil on some biological and behavioral traits of Trichogramma embryophagum and T. evanescens

Fumigant toxicity of the essential oil of Ferula assafoetida L. (Umbelliferae), a potent botanical insecticide against carob moth, was investigated under laboratory conditions on the fitness of two carob moth egg parasitoids, Trichogramma embryophagum (Hartig) and T. evanescens Westwood (Hymenoptera: Trichogrammatidae). The fertility life table parameters were assessed for both species at two different treatments, essential oil and ethanol as control. Although these two species were not affected similarly by the essential oil, exposure to 877 ppm (LC₀₁) in both species significantly reduced the longevity and fecundity of females, as well as the survival, developmental time, wing normality and sex ratio of their progeny. Effects of the essential oil on reproductive behavior of Trichogramma species were also investigated. Under oil treatment, despite that mate searching time increased, the percentage of mating occurrence, the duration of copulation, and sex ratio of F1 progeny declined. Given the negative effects of F. assafoetida essential oil on the two tested wasps, complementary studies are needed to develop the best management strategy for using the oil as environmentally friendly compound in combination with Trichogramma wasps against herbivorous insects.     

Laticiferous taxa as a source of energy and hydrocarbon

Twenty-nine laticiferous taxa of Apocynaceae, Asclepiadaceae, and Sapotaceae were screened for suitability as alternative sources of renewable energy, rubber, and phytochemicals and to select the most promising ones for large-scale cultivation. Of these,Allamanda violacea (14.9% protein, 13.8% polyphenol, 8.6% oil, 3.2% hydrocarbon),Catharanthus roseus (15.4% protein, 10.4% polyphenol, 11.5% oil, 1.9% hydrocarbon), andHolarrhena antidysenterica (14.2% protein, 16.4% polyphenol, 5.4% oil, 4.8% hydrocarbon) of Apocynaceae;Asclepias curassavica (19.3% protein, 6.5% polyphenol, 3.9% oil, 2.0% hydrocarbon), Calotropis gigantea (18.5% protein, 6.8% polyphenol, 7.0% oil, 2.8% hydrocarbon) of Asclepiadaceae;Mimusops elengi (11.3% protein, 9.7% polyphenol, 7.2% oil, 4.0% hydrocarbon) of Sapotaceae show promising potential for future petrochemical plantations; of all these taxa,Holarrhena antidysenterica yielded an unusually high percentage (4.8%) of hydrocarbon fraction followed byMimusops elengi (4.0%). NMR spectra confirmed the presence of cis-polyisoprene in all species studied exceptNerium indicum (white-flowered var.). These data indicate that the majority of the species under investigation may be considered for large-scale cultivation as an alternative source of rubber, intermediate energy, and other phytochemicals.     

Effects of Oil-Contaminated Sediments on Submerged Vegetation: An Experimental Assessment of Ruppia maritima

Oil spills threaten the productivity of ecosystems through the degradation of coastal flora and the ecosystem services these plants provide. While lab and field investigations have quantified the response of numerous species of emergent vegetation to oil, the effects on submerged vegetation remain uncertain. Here, we discuss the implications of oil exposure for Ruppia maritima, one of the most common species of submerged vegetation found in the region affected by the recent Deepwater Horizon oil spill. We grew R. maritima in a range of manipulated sediment oil concentrations: 0, 0.26, 0.53, and 1.05 mL oil /L tank volume, and tracked changes in growth (wet weight and shoot density/length), reproductive activity (inflorescence and seed production), root characteristics (mass, length, diameter, and area), and uprooting force of plants. While no statistical differences were detected in growth, plants exhibited significant changes to reproductive output, root morphology, and uprooting force. We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations. In addition, the roots growing in the high oil were shorter and wider. Plants in medium and high oil required less force to uproot. A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil. Given the importance of sexual reproduction for these plants, oil contamination may have substantial population-level effects. Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima.     

Chemical composition of essential oils of four Eucalyptus species and their phytotoxicity on silverleaf nightshade (Solanum elaeagnifolium Cav.) in Australia

Phytotoxicity and chemical composition of essential oils from four selected Eucalyptus species in Australia were investigated. Essential oils had stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.) when compared with a commercial eucalyptus oil and with 1,8-cineole. E. salubris oil had the highest inhibition index for silverleaf nightshade germination, root growth and shoot growth, while E. spathulata had the lowest inhibitory effect except root growth. Gas chromatography-mass spectrometry analysis revealed 56 compounds present in E. salubris oil, with 1,8-cineole (57.6?%), ??-pinene (10.9?%) and p-cymene (8.3?%) predominant. E. dundasii oil contained 55 identified compounds with 1,8-cineole (65.5?%) and ??-pinene (19.9?%) being the richest fractions. There were 56 compounds identified from E. brockwayii oil with ??-pinene (31.1?%), isopentyl isovalerate (20.2?%) and 1,8-cineole (16.9?%) as the most abundant components. E. spathulata oil contained 60 compounds, predominantly 1,8-cineole (52.9?%) and ??-pinene (31.0?%). Further study is required to determine the phytoxicity of the individual identified compounds on silverleaf nightshade and whether the observed phytotoxicity is attributable to a single compound or to the synergistic effects of several compounds.     

Chemical composition and antifungal effect of anise (Pimpinella anisum L.) fruit oil at ripening stage

The composition of the essential oil ofPimpinella anisum L fruit is determined by GC and GC-MS. The volatile oil content obtained by hydrodistillation was 1.91%. Ten compounds representing 98.3% of the oil was identified. The main constituents of he oil obtained from dried fruits were trans-a nethole (93.9%) and estragole (2.4%). The olfactorially valuable constituents that were found with concentration higher than 0.06% were (E)-methyeugenol, α-cuparene, α-himachalene, β-bisabolene, p-anisaldehyde and cis-anethole. Also, the different concentrations of anise oil exerted varying levels of inhibitory effects on the mycelial growth off/ternaria alternata, Aspergillus niger andAspergillus parasiticus used in experimental. The results showed that the most effected fungus from anise oil wasA. parasiticus, which is followed byA. niger andA. alternata. Individual of this plant oil may provide a useful to achive adequate shelf-life of foods.     

Influences of stearidonic acid-enriched soybean oil on the blood and organ biochemical parameters in rats

In this study, we administered various diets of stearidonic acid (SDA, 18:4n?3) soybean oil to rats and examined the subsequent blood and organ biochemical parameters. Male Wistar rats (seven rats/group, six groups total) were fed diets supplemented with a test oil for 4 weeks. Diets containing test oils were: FFC diet (fish-oil-free control diet), C diet (control group, assuming a Japanese diet), SDA25 diet (25% 18:4n?3 soybean oil in the C diet), SDA50 (50% 18:4n?3 soybean oil in the C diet), ALA diet (34% flaxseed oil in the C diet), and EPA+DHA diet (34% fish oil in the C diet). The intake of 18:4n?3 showed increased relative efficiency of 20:5n?3 accretions in serum and liver triacylglycerol and significantly decreased the serum triacylglycerol level in rats. The results suggested that the consumption of 18:4n?3 soybean oil may modify the lipid and fatty acid profiles of body fats, even when EPA and DHA derived from fish is consumed.