Essential oil extraction from onion using ethanol and CO2 as an extraction fluid mixture

Introduction: Essential oils are volatile chemical compounds, widely known by their fragrance, as well as by antimicrobial and antioxidant activities. These oils are generally extracted from aromatic plants in procedures using conventional solvents. Methods: In this study, essential oil was extracted from onion (previously chopped and dried) using a mixture of ethanol and CO2 as the extraction fluid. The essential oil obtained from the extraction was collected and purified and the mass was determined (by weighing) to evaluate the effect of CO2 flow on the yield. The essential oil extracted and purified was characterized to determine the acid and refraction indexes, viscosity, and specific mass. Results: The values obtained for refraction and acid indexes are within limits and similar to the average reported in literature. In all cases, when the CO2 was used, there was an increase the essential oil recovery. In terms of quality, the products from this process were characterized to determine the density, acid index and refraction index. The results obtained were similar to those published in the literature. Discussion: The proposed apparatus and CO2 methodology can be considered a good alternative to boost the extraction of essential oil aiming the obtaining of new products for use as raw materials in different industrial processes. Since this apparatus presents more than double extraction yield than Soxhlet experiment.

Identification of Chemicals Associated Gambusia affinis (Cyprinodontiformes: Poeciliidae), and Their Effect on Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) in the Laboratory

The western mosquitofish, Gambusia affinis (Baird & Girard), has been used worldwide for the control of larval mosquitoes for more than 100 yr. We found that the western encephalitis mosquito, Culex tarsalis Coquillett (Diptera: Culicidae), can detect the presence of G. affinis in oviposition sites based on associated chemicals, leading to a decrease in the number of egg rafts laid. Three volatile chemical compounds were identified in the headspace above the water where G. affinis had been held for 24 h. Oviposition bioassays conducted using standards of the volatile compounds identified (dimethyl disulfide [DMDS], dimethyl trisulfide [DMTS], and S-methyl methanethiosulphonate) found that females reduced oviposition only when low concentrations of DMTS were present, but this response was not consistent across all trials and concentrations tested. DMDS, DMTS, and S-methyl methanethiosulphonate are known bacterial metabolic waste products and may be the source of the compounds. Two nonvolatile compounds of interest were found to be present in the Gambusia-exudate water. After tasting Cx. tarsalis were deterred from ovipositing onto Gambusia-treated water from which the bacteria had been removed by filtration, indicating that the kairomone may consist of nonvolatile compound(s). One of the nonvolatile compounds isolated from the Gambusia-treated water has a benzene ring structure similar to that of cholesterol but the structure of the two nonvolatile deterrents remains to be fully characterized. Our research shows that three volatile compounds and two nonvolatile compounds are present in water associated with G. affinis (Poeciliidae: Gambusia) and affect the oviposition behavior of Cx. tarsalis in laboratory bioassays.

Antifungal efficacy of Moringa oleifera leaf and seed extracts against Botrytis cinerea causing gray mold disease of tomato (Solanum lycopersicum L.)

Drawbacks associated with the use of chemical fungicides to control plant pathogenic fungi such as Botrytis cinerea stimulate the need for alternatives. Therefore, the present study was carried out to determine the antifungal potentials of Moringa oleifera extracts against B. cinerea. Phytochemical analysis using qualitative chemical tests revealed the presence of huge amount of crucial phytochemicals compounds like phenolic compounds, alkaloids and saponins in the M. oleifera leaf extract. Antifungal bioassay of the crude extracts indicated better mycelial growth inhibition by methanol leaf extract (99%). The minimum inhibitory concentration (MIC) was 5 mg/ml with 100% spore germination inhibition and minimum fungicidal concentration (MFC) was 10 mg/ml with 98.10% mycelial growth inhibition using broth micro dilution and poisoned food techniques. Gas chromatography–mass spectrometry (GC-MS) analysis led to the identification of 67 volatile chemical compounds in the leaf extract with 6-decenoic acid (Z)- (19.87%) was the predominant compound. Further chemical elucidation of the crude extracts performed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) showed the presence of non-volatile chemical compounds, mostly flavones, flavonoids and phenolic acids (i.e. quercetin and kaempferol). Scanning electron microscopy and transmission electron microscopy analysis showed positive effect of M. oleifera leaf extract on the treated conidia and mycelium of B. cinerea. Findings revealed that irreversible surface and ultra-structural changes with severe detrimental effects on conidia and mycelium morphology compared to control treatment. Overall findings suggested that M. oleifera leaf extract is a promising candidate for biological control of fungal pathogens, thus limiting overdependence on chemical fungicides.

Investigation of body secretions as bioindicators in cattle estrus detection

The accurate determination of estrus has a fundamental role in cattle reproduction management. The determination of volatile chemical compounds (pheromones) secreted only during estrus in all body fluids can be used for determining accurate estrus time and artificial insemination time and have a potential role in technological animal reproduction control. In this study, Holstein cows were synchronized and their sudor, urine, feces, milk, saliva, vaginal secretions, and blood samples were taken in the preestrus, estrus, and postestrus periods and analyzed by gas chromatography-mass spectrometry for determination of volatile odor compounds. A total of 531 volatile compounds were detected in the preestrus period, 538 in the estrus period, and 494 in the postestrus period. Among these, 8 compounds were found to be common in all body fluids and the ratio of these compounds to those detected in all body fluids was 2.6%. Especially in the estrus, 3-methyl pentane, hexanal, 4-methylphenol (p-cresol), phenylacetaldehyde, 3-phenylpropiononitrile, 1 H-indole, cyclotetrasiloxane octamethyl and pentane 2-methyl were detected. Biotechnology devices such as artificial nose with sensors can be developed, recognizing estrus-specific volatile compounds detected from all body fluids only in estrus period.

Respostas quimiotáxicas de Orius insidiosus (Say) ao complexo Nicotiana tabacum L., Myzus persicae (Sulzer) e fitormônios

Resumo. Orius insidiosus (Say) (Hemiptera: Anthocoridae), conhecido como um dos principais predadores de pequenos artrópodes como tripes, pulgões, ácaros e pequenas lagartas sendo uma espécie polífaga, que pode ser encontrada em diferentes agroecossistemas. Este predador é mundialmente usado para controle de populações de pulgões, os quais podem ser vetores de diversas viroses que ocorrem em tabaco. A sobrevivência de predadores pode estar associada à sua capacidade de utilizar pistas químicas provenientes das presas ou das plantas em herbivoria para localizar sítios de alimentação. A emissão de voláteis de defesa indireta de plantas é um dos mecanismos utilizado para atrair inimigos naturais e também pode ser ativado na presença de fitormônios, como metil jasmonato e ácido salicílico. Este trabalho teve como objetivo avaliar as respostas quimiotáxicas de fêmeas de O. insidiosus frente a plantas Nicotiana tabacum L. (Solanaceae) infestadas ou não com Myzus persicae (Sulzer)(Hemiptera:Aphididae), ao odor do pulgão e a plantas aspergidas com ácido salicílico e metil jasmonato. As fêmeas foram avaliadas em olfatômetro de dupla escolha, expostas, individualmente, a cada um dos tratamentos contrastando com o controle em sala climatizada (25 ± 5 ºC, 60 ± 10% UR). As fêmeas somente foram atraídas para plantas quando estavam infestadas (p < 0,001), porém o odor de pulgões, isoladamente, não teve efeito atrativo (p = 0,4386). Plantas aspergidas com fitormônios não atraíram as fêmeas do predador (p > 0,05). Voláteis produzidos por plantas de tabaco sob a ação da herbivoria de M. persicae atraem O. insidiosus o que evidencia que esta espécie utiliza sinomônios como estratégia de busca e localização de presas.Responses of Orius insidiosus (Say) to Nicotiana tabacum L., Myzus persicae (Sulzer) complex and phytohormonesAbstract. Orius insidiosus (Say) (Hemiptera: Anthocoridae) is one of the major predators of small arthropods such as thrips, aphids, mite, eggs and small caterpillars. It is a polyphagous specie, and can be find in many agrosystems. This predator is used globally to control populations of aphids, which can be vectors of several viruses that occur in tobacco. The predator's survival may be associated with their ability for use chemical cues from the prey or plants damaged by herbivores to locate feeding sites. The emission of volatile chemical compounds is one of the defense mechanisms of plants to attract natural enemies. The emission of volatiles from plants associated with indirect defense is used to attract natural enemies and can also be activated in the presence of phytohormones such as methyl jasmonate and salicylic acid. This work aimed to evaluate the chemotactic responses of O. insidiosus females against plants Nicotiana tabacum L. (Solanaceae) infested and not infested with Myzus persicae (Sulzer) (Hemiptera: Aphididae), odor of aphid and plants sprayed with salicylic acid and methyl jasmonate. The females were evaluated in a double-choice olfactometer, individually, exposed to each of the treatments, contrasting with the control in a labor room (25 ± 5 ºC, 60 ± 10% RH). Females were only attracted to plants when they were infested (p <0.001), but the aphid odor alone had no attractive effect (p = 0.4386). None of the plants with phytohormones attracted females (p> 0.05). Volatile compounds produced by tobacco plants under the action of herbivory of M. persicae attract O. insidiosus indicating that this species uses synomones as search strategy and location of prey.

ANALYSIS OF VOLATILE AND QUALITY CONTROL IN NAIL POLISH

Nail polishes are one of the most widely used cosmetics in the world and have complex chemical composition. In this study, labels were evaluated and physicochemical and microbiological analysis were performed in order to evaluate the quality of the marketed nail polishes. The identification of volatile chemical compounds and toluene quantification were determined by GC-MS. The results showed that 62% of the nail polishes did not present one or more regulated items for labeling. Density analysis presented values close to those recommended. The free formaldehyde test indicated the possible presence of this compound in concentrations above 0.01% in 93% of the samples. Microbiological analysis evidenced microbial growth and the presence of the pathogens Staphylococcus aureus and/or Escherichia coli. The CG-MS analysis allowed the identification of 29 volatile compounds, such as ethyl acetate, butyl acetate, toluene, N-ethyl-2-methylbenzenesulfonamide, dibutyl phthalate and acetyl tributyl citrate. Toluene was identified in samples whose label does not mention its presence. Toluene was identified in samples whose labels did not mention its presence. The results showed the need of a better quality control of the nail polishes available to the consumer, since the lack of information on the labels and the presence of pathogens and harmful substances to health may compromise their use.

Host-seeking behavior of the Heterorhabditis amazonensis nematode in response to stimulant sources1

ABSTRACT Several species of entomopathogenic nematodes have different host-seeking methods, and could be considered as "ambusher" or "cruiser". These differences may depend on how the nematodes detect the volatile signals used as cues for foraging. This study aimed to evaluate the locomotor response of Heterorhabditis amazonensis RSC5 to the compounds from root exudates of different plants, as well as to stimulants produced by the presence of insects or to the feeding activity of insects on plants. Arenas with agar-water substrates, containing root exudates from corn, bean, soybean, cucumber, garlic and tomato seedlings, were assembled to determine the substrates possibly preferred by H. amazonensis.Arenas with sand were also constructed to include, besides the seedling root exudates, treatments containing Spodoptera frugiperda, garlic seedlings and S. frugiperda feeding on garlic seedlings. The H. amazonensis species was attracted to the volatile chemicals emitted by all the root exudates tested, especially the exudate from garlic seedlings. However, it showed the greatest attraction to the combination of garlic seedlings and S. frugiperda, indicating that the search of H. amazonensis for its host is enhanced by the association between the insect and the volatile chemical compounds produced by plants, when attacked by insects.