scholarly journals Activity of terpenes derived from essential oils against Sarcoptes scabiei eggs

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Meilin Li ◽  
Shunlong Liu ◽  
Zhijuan Yin ◽  
Charlotte Bernigaud ◽  
Jacques Guillot ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Essential Oils ◽  
Exposure Period ◽  
Sarcoptes Scabiei ◽  
Effective Concentration ◽  
Ovicidal Activity ◽  
Developmental Arrest ◽  
Paraffin Oil ◽  
Significant Obstacle ◽  
Median Effective Concentration

Abstract Background The limited ovicidal activity of currently available acaricides is a significant obstacle to efficacious scabies treatment. Several essential oils or their respective components have proved to be active against the eggs of arthropods, mainly lice and ticks. Information on the activity of these oils and/or components against the eggs of mites remains very limited. The aim of this study was to assess the activity of six terpenes (carvacrol, eugenol, geraniol, citral, terpinen-4-ol and linalool) commonly found in essential oils against the eggs of Sarcoptes scabiei. Methods Sarcoptes eggs were exposed to paraffin oil containing 1, 2.5, or 5% of each terpene tested. After a 12-h exposure period, the eggs were washed and placed in paraffin oil for hatching. Embryonic development following treatment was assessed every day to determine the stage of developmental arrest. Results The median effective concentration to obtain 50% egg mortality (EC50) was 0.5, 0.9, 2.0, 4.8, 5.1 and 9.8% for carvacrol, eugenol, geraniol, citral, terpinen-4-ol and linalool, respectively. The microscopic images of eggs after each treatment indicated that these six terpenes may act by penetrating through the aeropyles on the egg surface. Conclusions In conclusion, carvacrol, eugenol and geraniol possess significant ovicidal activities, which should be considered as promising ovicidal agents for the treatment of scabies. Graphical Abstract

scholarly journals Ovicidal Activity of Essential Oils against Red Flour Beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

1970 ◽  
Vol 17 ◽  
pp. 57-62 ◽  
Author(s):  
Mina Mondal ◽  
M Khalequzzaman
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Tribolium Castaneum ◽  
Exposure Period ◽  
Red Flour Beetle ◽  
Mortality Data ◽  
Fumigant Toxicity ◽  
Ovicidal Activity ◽  
Flour Beetle ◽  
Ovicidal Effect

Context: The essential oils are being tried as potential candidates for pest and disease management. Several essential oils of botanical origin have been reported for their repellant, toxic and developmental inhibitory activities. The ovicidal effect of essential oil is probably the major factor in the suppression of the development of adults from treated eggs.Objectives: To investigate the ovicidal effect of vapours of five essential oils viz., cardamom (Elletaria cardamomum L.), cinnamon (Cinnamomum zeylanicum Blume), clove (Sygium aromaticum L. Merrill. et. Perry), Eucalyptus spp. and neem (Azadirectica indica A. juss) against the eggs of red flour beetle, Tribolium castaneum (Herbst).Materials and Methods: Ten eggs (24 h old) of T. castaneum were placed in each petridish with wheat flour as food medium and without flour medium and then the petridish were kept inside 650 ml jars with screwed lids. Aliquots of 0.5 ml of each dose of essential oils were applied on filter paper attached to the lower side of the lids. The exposure periods were 24, 48, 72 and 96 h, respectively. After treatment periods, petridishes were taken out of the jars and the final mortality counts were made after 11 days. Mortality data were subjected to probit analysis. Results: The oils had high-fumigant activity against eggs and toxicity progressively increased with increase in exposure time and concentration. At the highest concentration of 5.769 mg/l air and exposure period of 24 h, cinnamon oil achieved 100% mortality in flour and without flour media. The vapours of essential oils from cardamom and clove resulted in 100% mortality of the eggs. Neem oil achieved mortalities as high as 51.66 and 50% mortality at the highest concentration and exposure period in with-flour and without flour medium respectively. At a concentration of 5.769 mg/ l air cardamom oil, the LT90 values were 50.80 and 62.78 h for with-flour and without flour medium respectively.Conclusion: The essential oils of cinnamon and clove, proved to be promising as control agents against stored-product insects, especially T. castaneum.Key words: Essential oil; Fumigant toxicity; Ovicidal activity; Tribolium castaneumDOI: 10.3329/jbs.v17i0.7102J. bio-sci. 17: 57-62, 2009

scholarly journals Small Molecule Inhibitors of White Spot Syndrome Virus: Promise in Shrimp Seedling Culture

2021 ◽  
Vol 22 (7) ◽  
pp. 3450
Author(s):  
Lei Liu ◽  
Li-Peng Shan ◽  
Yan Zhou ◽  
Jiong Chen
Keyword(s):  
Litopenaeus Vannamei ◽  
White Spot Syndrome Virus ◽  
Environmental Issues ◽  
Therapeutic Strategies ◽  
Effective Concentration ◽  
White Spot ◽  
Rapid Production ◽  
White Spot Syndrome ◽  
Median Effective Concentration ◽  
Artificial Pressure

Rapid production of prawn (Litopenaeus vannamei) under artificial pressure can result in a series of obvious challenges and is vulnerable to serious losses related to aquatic environmental issues and the unrestrained outbreak of white spot syndrome (WSS). However, to date, there are no therapeutic strategies to contain the spread of the virus. Here, we synthesized 27 coumarin deriv-atives and evaluated their anti-white spot syndrome virus (WSSV) activity in L. vannamei larvae. We demonstrated that electron-withdrawing and electron-giving substituent groups play an im-portant role in reducing toxicity and WSSV replication, respectively. Two coumarin C2 (2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) and C7 (2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) were regarded as the most promising anti-WSSV compounds with maximum antiviral response <5% and median effective concentration <10 mg/L. The mortality of WSSV-infected larvae decreased by more than 60% after exposure to C2 and C7. With continuous immersion of C2 and C7 exchange, the mortality further decreased to 40% at 120 h.Additionally, C2 and C7 are the relatively stable in aquacultural water, making these agents

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

scholarly journals Andean Plants Essential Oils: A Scented Alternative to Synthetic Insecticides for the Control of Blowflies

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 894
Author(s):  
Priscilla Farina ◽  
Francesca Venturi ◽  
Roberta Ascrizzi ◽  
Guido Flamini ◽  
Rodrigo Daniel Chiriboga Ortega ◽  
...  
Keyword(s):  
Essential Oils ◽  
Allium Sativum ◽  
Toxicity Tests ◽  
Ovicidal Activity ◽  
Human Pathogens ◽  
Fish Products ◽  
Behavioural Test ◽  
Andean Plants ◽  
Pleasant Odour ◽  
Topical Applications

Blowflies are vectors of microorganisms and human pathogens, and their maggots cause myiasis in vertebrates and infest and spoil meat and fish products. Essential oils (EOs) from spices were proven to be a safer and more sustainable alternative to synthetic insecticides for the control of blowflies and are suitable for protecting food from such pests. However, some EOs are not acceptable for environmental or topical applications due to their strong, unpleasant odour. In this study, we measured the acute toxicity and the repellence of two EOs extracted from the Andean plants Aloysia citrodora Palau and Bursera graveolens (Kunth) Triana and Planch., both known for their pleasant odour, against the blue blowfly Calliphora vomitoria (L.) (Diptera: Calliphoridae). We also compared their bioactivity with that of the Allium sativum L. EO, which is very effective but bad-smelling. The A. citrodora EO was mainly rich in oxygenated monoterpenes, the most abundant of which were geranial (26.8%) and neral (21.0%). The B. graveolens EO was chiefly composed of monoterpene hydrocarbons, mostly represented by limonene (46.2%). According to the sensory description, the best odour profile was associated with the A. citrodora EO, while the olfactory expression of the EO from B. graveolens was negatively affected by a strong odour of “mouldy lemon”. The behavioural test showed that the A. citrodora EO was more repellent than that of A. sativum and, on the contrary, that the B. graveolens EO was attractive. The toxicity tests showed that the EOs of both Andean plants have a clear toxic effect on the C. vomitoria eggs and adults. In terms of ovicidal activity, there were no significant differences among the effects of the three tested EOs. On the adult flies, the toxicity of the two EOs of the Andean plants was much lower than that of A. sativum (LC50 fumigation = 1.86 μL EO L−1 air; LC50 ingestion = 8.10 μL EO mL−1 gel) both by fumigation (LC50 = 23.66 and 25.30 μL EO L−1 air for A. citrodora and B. graveolens, respectively) and ingestion (LC50 = 36.65 and 44.97 μL EO mL−1 gel for A. citrodora and B. graveolens, respectively), while, by contact, the A. citrodora EO (LD50 = 0.27 μL EO insect−1) was more toxic than the A. sativum EO (LD50 = 0.46 μL EO insect−1).

scholarly journals ADULTICIDAL ACTIVITY OF BOTANICAL OILS BY IMPREGNATED PAPER ASSAY AGAINST CULEX QUINQUEFASCIATUS SAY

2017 ◽  
Vol 9 (5) ◽  
pp. 156
Author(s):  
M. Ramar ◽  
S. Ignacimuthu ◽  
P. Manonmani ◽  
K. Murugan
Keyword(s):  
Essential Oils ◽  
Culex Quinquefasciatus ◽  
Mosquito Control ◽  
Exposure Period ◽  
Adult Mortality ◽  
Clove Oil ◽  
Chemical Insecticide ◽  
Plant Essential Oils ◽  
Knock Down ◽  
Indigenous Plant

Objective: The present study was undertaken with the aim of finding out the efficacy of essential oils (EOs) as anti-mosquito agents for commercial purposes. Plant source insecticides as an alternative to chemical insecticide, this study were evaluated to assess the knock-down and adulticidal prospective of the essential oils against Culex quinquefasciatus. The plant essential oil is largely cultivated throughout India and in all Tropical countries.Methods: The selected botanical essential oils were procured from commercial producers of plant essential oils and aromatic substances were used in this study. Knock-down and Adulticidal bioassay was performed according to WHO protocol. A single dose of the essential oils was used in the preliminary screening. 20 adult mosquitoes (3-5 d old glucose fed mosquitoes) were exposed on treated paper for one hour and knocked down and live mosquitoes were counted at 5 minute intervals.Results: Among the twenty three oils tested, 100% knock-down and adult mortality was recorded at 10%/cm2dose of calamus, camphor, cinnamon, citronella, clove, eucalyptus, lemongrass, pine, thyme and tulsi oils respectively. At 10 % concentration, clove oil (KT50 =1.8 and KT90 = 2.03 min) was found to be the most potential treatment. After 15 min exposure period clove oil registered the lowest knock-down dosewhich was calculated as (KD50 =1.8 %/cm2and KD90 =11.2 %/cm2). The lower and upper 95 % confidence limits for clove oil were calculated as 0.2 and 4.2 min respectively.Conclusion: From the results it can be concluded that the adult of the Cx. quinquefasciatus were susceptible to the essential oils. Such findings would be useful in promoting research aiming at the development of new agent for mosquito control on basis of chemical compounds from indigenous plant sources as an alternative to chemicals.

Early Developmental Arrest During Immersion of Eggs of a Tropical Fresh-Water Turtle, Chelodina-Rugosa (Testudinata, Chelidae), From Northern Australia

1993 ◽  
Vol 41 (1) ◽  
pp. 37 ◽  
Author(s):  
R Kennett ◽  
A Georges ◽  
M Palmerallen
Keyword(s):  
Embryonic Development ◽  
Experimental Evidence ◽  
Fresh Water ◽  
Water Levels ◽  
Northern Australia ◽  
Developmental Arrest ◽  
Hypoxic Conditions ◽  
Oxygen Tensions ◽  
Early Developmental ◽  
Monsoonal Season

Freshly laid. eggs of Chelodina rugosa survived for up to 12 weeks when immersed in water and subsequently underwent successful incubation and normal hatching. Embryonic development was arrested during immersion, remained arrested in an atmosphere of nitrogen, and recommenced when eggs were exposed to air. The hypoxic conditions during immersion appear to extend the arrest typical of turtle embryos during their period in the oviducts. Freshly laid eggs of the temperate-zone C. longicollis died when immersed for longer than one week and eggs of both species died when immersed after post-laying embryonic development had commenced. These results, supported by anecdoctal and experimental evidence, suggest that C. rugosa lays its eggs in saturated or flooded ground in the late wet or early dry monsoonal season. Embryonic development presumably remains arrested until water levels drop and oxygen tensions in the nest rise by diffusion through the drying soil. Partly developed embryos in nests that are flooded after laying would perish. In contrast, C. longicollis of temperate Australia nests only in relatively dry substrates, and its eggs appear not be have evolved the capacity to withstand immersion.

Using certain commercially available glass-bottomed dish with paraffin oil impacts the embryonic development of oocytes

2007 ◽  
Vol 88 ◽  
pp. S310-S311
Author(s):  
H.-C. Chang ◽  
J. Grifo ◽  
C. McCaffrey ◽  
L.C. Krey ◽  
N. Noyes
Keyword(s):  
Embryonic Development ◽  
Paraffin Oil

Median Effective Concentration

2016 ◽  
Author(s):  
John H. Duffus ◽  
Monica Nordberg ◽  
Douglas M. Templeton
Keyword(s):  
Effective Concentration ◽  
Median Effective Concentration
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