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Inhibition of acetylcholinesterases by pulegone-1,2-epoxide
Abstract
Toxicological observations indicate that pulegone-1,2-epoxide, isolated from the medicinal plant, poleo (Lippia stoechadifolia), is an insect neurotoxin. These observations prompted studies of the action of pulegone-1,2-epoxide on acetylcholinesterase activity. Kinetic analyses of the hydrolysis of acetylthiocholine by eel acetylcholinesterase in the presence of pulegone-1,2-epoxide shows an irreversible inhibition of the enzyme in a manner similar to that shown for carbamates. Five other monoterpenoids were similarly tested for their effects on acetylcholinesterase, and comparison of the inhibitions suggests that both the epoxy and keto groups are required for irreversible inhibition. Although pulegone-1,2-epoxide inhibits both house fly and Madagascar roach (Gromphadorhina portentosa) acetylcholinesterases in vitro, no correlation between inhibition of roach acetylcholinesterases in vivo and the onset of symptoms preceding death was shown.
... K i value (representing dissociation constant of EI complex in enzyme -inhibitor reaction) is independent of substrate and enzyme concentration but depends on the type of the enzyme and the inhibitor. It is more suitable for comparison between the assays, and thus is given in Tables 3-6, but it is scarcely reported [3,[58][59][60][61][62][63][64][65][66][67][68]. ...
... K i value was determined in several cases for monoterpenes and monoterpenoids where kinetic features of these compounds were studied for electric eel AChE. The following K i values were reported for: 1,8-cineole (0.0007, 0.025 and 0.03 mM) [65][66][67]; pulegone (0.011, 0.39 and 0.85 mM) [62,65,66]; camphor (0.05 mM) [64]; geraniol (0.10 mM) [64]; γ-terpinene (0.20 mM) [64]; linalool (0.22 and 0.30 mM) [64,65]; (S)-(+)-carvone (0.30 and 0.68 mM) [62,64]; citral (0.39 mM) [65]; fenchone (0.40 mM) [64]; (-)bornyl acetate (0.48 mM) [65]; (R)-(-)-carvone (0.82 mM) [62]; piperitenone oxide (2.19 mM) [62]; (+)-limonene (3.48 mM) [62]; (+)-limonene oxide (3.64 mM) [62]; terpinene-4ol (4.70 mM) [67]. ...
... K i value was determined in several cases for monoterpenes and monoterpenoids where kinetic features of these compounds were studied for electric eel AChE. The following K i values were reported for: 1,8-cineole (0.0007, 0.025 and 0.03 mM) [65][66][67]; pulegone (0.011, 0.39 and 0.85 mM) [62,65,66]; camphor (0.05 mM) [64]; geraniol (0.10 mM) [64]; γ-terpinene (0.20 mM) [64]; linalool (0.22 and 0.30 mM) [64,65]; (S)-(+)-carvone (0.30 and 0.68 mM) [62,64]; citral (0.39 mM) [65]; fenchone (0.40 mM) [64]; (-)bornyl acetate (0.48 mM) [65]; (R)-(-)-carvone (0.82 mM) [62]; piperitenone oxide (2.19 mM) [62]; (+)-limonene (3.48 mM) [62]; (+)-limonene oxide (3.64 mM) [62]; terpinene-4ol (4.70 mM) [67]. ...
Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).
Compounds that act as cholinesterase inhibitors still represent the only pharmacological treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds, found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene, δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc.
Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).
... The mechanism of the larvicidal action of the fatty acids elaidic acid and arachidic acid may involve interfering with the octopaminergic system, whereas linoleic acid and linolenic acid might act on both AChE and octopaminergic receptors 42 . Certain terpenoids inhibit AChE from houseflies, Madagascar roaches 55 , and head lice 56 . A relationship between insect toxicity and electric eel AChE inhibition by terpenoids has been reported 57 , whereas no direct correlation between the insecticidal and AChE inhibitory activities of terpenoids has been reported 42,55,56 . ...
... Certain terpenoids inhibit AChE from houseflies, Madagascar roaches 55 , and head lice 56 . A relationship between insect toxicity and electric eel AChE inhibition by terpenoids has been reported 57 , whereas no direct correlation between the insecticidal and AChE inhibitory activities of terpenoids has been reported 42,55,56 . In addition, the major mechanisms of resistance to insecticides currently used to control mosquitoes include target site insensitivity, which reduces the sensitivity of sodium channels of the nervous system to pyrethroid insecticides, or sensitivity of the key enzyme AChE to OP and carbamate insecticides, as well as enhanced metabolic detoxification in various groups of insecticides 58 . ...
This study was performed to determine the toxicity and possible mechanism of the larvicidal action of honokiol, extracted from Magnolia denudata seeds, and its 10 related compounds against third-instar larvae of insecticide-susceptible Culex pipiens pallens, Aedes aegypti, and Aedes albopictus and Anopheles sinensis resistant to deltamethrin and temephos. Honokiol (LC50, 6.13–7.37 mg/L) was highly effective against larvae of all of the four mosquito species, although the toxicity of the compound was lower than that of the synthetic larvicide temephos. Structure–activity relationship analyses indicated that electron donor and/or bulky groups at the ortho or para positions of the phenol were required for toxicity. Honokiol moderately inhibited acetylcholinesterase and caused a considerable increase in cyclic AMP levels, indicating that it might act on both acetylcholinesterase and octopaminergic receptors. Microscopy analysis clearly indicated that honokiol was mainly targeted to the midgut epithelium and anal gills, resulting in variably dramatic degenerative responses of the midgut through sequential epithelial disorganization. Honokiol did not affect the AeCS1 mRNA expression level in Ae. aegypti larvae, but did enhance expression of the genes encoding vacuolar-type H+-ATPase and aquaporin 4, indicating that it may disturb the Na+, Cl− and K+ co-transport systems. These results demonstrate that honokiol merits further study as a potential larvicide, with a specific target site, and as a lead molecule for the control of mosquito populations.
... For examples, they are neuro-toxicants against different insect species (Coats et al., 1991 andEnan, 1998). They have been shown to inhibit both the GABA receptor in marine algae (Coats, 1990), and inhibit acetylcholinesterase (AChE) isolated from different insect species (Grundy andStill, 1985 andRyan andByrne, 1988). Monoterpenes blocked the octopamine receptor binding activity of American cockroaches under in vitro treatment (Enan, 2001). ...
... For examples, they are neuro-toxicants against different insect species (Coats et al., 1991 andEnan, 1998). They have been shown to inhibit both the GABA receptor in marine algae (Coats, 1990), and inhibit acetylcholinesterase (AChE) isolated from different insect species (Grundy andStill, 1985 andRyan andByrne, 1988). Monoterpenes blocked the octopamine receptor binding activity of American cockroaches under in vitro treatment (Enan, 2001). ...
Two essential oils have been isolated from air-dried leaves of Mentha microphylla and Lantana camara using hydrodistillation method. Chemical profile of the essential oils was examined by gas chromatography-mass spectrometry (GC-MS) analysis. The chemical analysis showed that both oils contained hydrocarbons such as monoterpenes, sesquiterpenes and diterpenes, and oxygenated hydrocarbons such as monoterpeniods, sesquiterpenoids, diterpenoids and others. The isolated oils were tested for their insecticidal activity against the adults of the three stored product insects; Sitophilus oryzae, Tribolium castaneum and Rhyzopertha dominica, and mosquito larvae of Culex pipiens. In addition, the antifungal activity of both oils have been evaluated against three plant pathogenic fungi; Rhizoctonia solani, Botrytis fabae and Pythium debaryanum. In contact toxicity test, the M. microphylla oil showed a strong insecticidal activity against the three tested stored product insects. Values of LC 50 of the oil were 0.0075, 0.0089 and 0.028 mg/cm 2 on S. oryzae, T. castaneum and R. dominica, respectively. On the other hand, Lantana camara oil was less potent than M. microphylla oil on the three tested insects. Moreover, M. microphylla oil revealed insecticidal activity comparable with a reference insecticide, malathion against R. dominica and T. castaneum. This oil also displayed a very promising insecticidal activity against S. oryzae and T. castaneum in fumigation assay. The two essential oils exhibited pronounced larvicidal activity against C. pipiens. However, L. camara oil (LC 50 = 18.08 µg/ml) was more toxic than M. microphylla oil (LC 50 = 42.76 µg/ml). When tested for antifungal activity, M. microphylla oil showed higher activity than L. camara oil against the three tested fungi; R. solani, B. fabae and P. debaryanum, with EC 50 values of 70.79, 88.78 and 82.36 µg/ml, respectively.
... GC-MS of the E. cladocalyx essential oil revealed a significant presence of monoterpenes known for their antimicrobial activities. This finding is in agreement with Grundy & Still (1985), who reported that cyclic monoterpenes could integrate into cell membrane, Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas/ 533 leading to membrane expansion and increased fluidity, ultimately facilitating the efflux of intracellular components and causing microbial death. Additionally, minority compounds may interact in a synergistic, additive, or antagonistic manner (Bakkali et al., 2008;Wang et al., 2008). ...
This study aimed to evaluate the phytochemical composition, antioxidant properties, and antibacterial activities of the essential oil and extracts from Eucalyptus cladocalyx using leaves collected from the Baïnem forest. Essential oil was extracted via hydrodistillation with a Clevenger apparatus, and the methanolic extract was prepared using a rotary evaporator. Prior to analysis, 0.1 µL of the essential oil was diluted in 1:10 hexane solution for GC-MS analysis, which identified 30 constituents, with 1,8-cineole and p-cymene as the primary components. The antioxidant activity assessment demonstrated that the methanolic extract effectively neutralized DPPH, achieving 55% inhibition at a concentration of 500 µg/mL. Furthermore, the essential oil exhibited excellent antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Klebsiella oxytoca as tested using the aromatogram method, while the methanolic extract showed notable antibacterial activity specifically against Klebsiella oxytoca. These findings suggest that the essential oil of E. cladocalyx has potential applications as a disinfectant in the pharmaceutical industry, while the extracts may serve as a food additive.
... was studied by Kinetic analyses , when showed an inhibition of the enzyme .A group of monoterponoides have tested their toxicity effects on acetylcholinesterase, including ; limonene oxide ,pulegone , d-carvone , and limonene. Although pulegone-1,2-epoxide inhibits both Madagascar roach (Gromphadorhina portentosa) acetylcholinesterases and house fly and in vitro, no correlation was found between roach acetylcholinesterase inhibition and the onset of symptoms preceding death in vivo (Grundy and Still, 1985). ...
... Plant oils blocked spiracles disrupting gaseous exchange [123]. For example, Grundy and Still [124] stressed that, Pulegone −1, 2, epoxide [a menoterpenoid] isolated from Lippia steochadifelia is an insect neurotoxin that inhibits the production of a neurochemical transmitter responsible for stimulating the secretion of enzyme, acetylcholinesterase in Musca domestica [125] and T. granarium. Some botanical extracts, therefore, deterred oviposition, egg hatchability, postembryonic development and progeny production [126]. ...
Wheat grains as one of the world’s most nutritious crops are threatened by several insect pests damaging their quality thereby imparting economic losses worth millions of dollars annually. Strategies have been devised to protect the stored grains from insect pests’ attacks. One of the most widely used control measures was the application of synthetic chemical insecticides that posed negative consequences ranging from toxicity to non-target organisms (man inclusive), expensive and non-biodegradable. Botanical pesticides have proved more effective alternatives as they are specific in action, cheaper and eco-friendly. This chapter, therefore, reviewed and analysed different methods employed in controlling insect pests of stored wheat grains giving more emphasis to botanicals.
... In our study, the Ki value for carvone (270 µg/mL or 1.79 mM) was the lowest suggesting its strong binding to the enzyme. Previously, a lower K i value (0.68 mM) was reported for carvone by Grundy et al. [51]. ...
Neurodegeneration diseases (NDs) are a group of complex diseases primarily characterized by progressive loss of neurons affecting mental function and movement. Oxidative stress is one of the factors contributing to the pathogenesis of NDs, including Alzheimer’s disease (AD). These reactive species disturb mitochondrial function and accelerate other undesirable conditions including tau phosphorylation, inflammation, and cell death. Therefore, preventing oxidative stress is one of the imperative methods in the treatment of NDs. To accomplish this, we prepared hexane and ethyl acetate extracts of Anethum graveolens (dill) and identified the major phyto-components (apiol, carvone, and dihydrocarvone) by GC-MS. The extracts and major bioactives were assessed for neuroprotective potential and mechanism in hydrogen peroxide-induced oxidative stress in the SH-SY5Y neuroblastoma cell model and other biochemical assays. The dill (extracts and bioactives) provided statistically significant neuroprotection from 0.1 to 30 µg/mL by mitigating ROS levels, restoring mitochondrial membrane potential, reducing lipid peroxidation, and reviving the glutathione ratio. They moderately inhibited acetylcholine esterase (IC50 dill extracts 400–500 µg/mL; carvone 275.7 µg/mL; apiole 388.3 µg/mL), displayed mild anti-Aβ1–42 fibrilization (DHC 26.6%) and good anti-oligomerization activity (>40% by dill-EA, carvone, and apiole). Such multifactorial neuroprotective displayed by dill and bioactives would help develop a safe, low-cost, and small-molecule drug for NDs.
... Other compounds are being studied with a neurophysiological focus, such as sylphines, a rare class of tricyclic sesquiterpenes extracted from the leaves of Senecio palmensis that act as antagonists of the ɤ-aminobutyric system (GABA), acting more specifically in chloride receptor channels (Bloomquise et al., 2008). Another active ingredient with neurotoxic activity is the monoterpenoid pulegone-1,2-epoxide isolated from the plant Lippia steochadifolia (Grundy et al., 1985). The authors found that this compound acts as a carbamate, with an irreversible effect on the inhibition of the enzyme acetylcholinesterase. ...
The leaf-cutting ant Atta sexdens stands out as a pest of several crops of economic importance. The main control method for this species is the application of ant baits. However, one of the most used active ingredients in the ant baits, sulfluramid, was classified as an organic pollutant, highlighting the urgent need to seek new active ingredients with greater ecological and environmental safety. The present goal is to evaluate the bioactivity of botanical extracts in workers of the leaf-cutting ant A. sexdens by ingestion, aiming to select extracts with essential characteristics for use in toxic baits for the subsequent isolation of substances and prospection of insecticides. Insect survival in the first evaluation (24 h) was high in all treatments with extracts. Survival time varied between treatments, with mortality reaching maximum values between 10 and 20 days for most of the treatments. At 21 days, live ants were observed only in treatments T3 (M. maracasana-stem) and T4 (C. mastigophorus-bark), with survival of 10% and 3.3%, respectively, not significantly differing between them. The extracts of Metrodorea maracasana, Conchocarpus mastigophorus, Erythoxylum macrocalyx, and Erythoxylum plowmanii showed insecticidal activity against A. sexdens workers. The insecticidal activity of the species Erythoxylum macrocalyx, E. plowmanii, Metrodorea maracasana, and Conchocarpus mastigophorus against A. sexdens workers is shown for the first time. The studied extracts have potential for the fractionation and selection of substances responsible for insecticidal activity, allowing for the prospection of toxic baits.
... These compounds can be the basis of the anticholinesterase activity examined in this study. In vitro, several monoterpenes from essential oils are potent inhibitors of AChE [55]. Camphor, o-cymene, cineole, trans-geraniol, and trans-citral have all been found in the aerial portions of F. cretica in prior research [56]. ...
This is the first study aimed to investigate the anti-cholinesterase (anti-Alzheimer), anti-lipase, antioxidant and photoprotective effects of various organic extracts prepared from the aerial parts of Fagonia bruguieri DC species endemic to southern Algeria. The research was also aimed to determine the total phenolics and flavonoid contents and evaluate in vitro pharmacological activities of these extracts by means of spectrophoto-metric analysis. The in vitro antioxidant properties of F. bruguieri were examined by DPPH radical scaveng-ing, b-carotene bleaching, ferric reducing power, cupric reducing antioxidant capacity (CUPRAC), free galvinoxyl radical (GOR), and O-phenanthroline assays. The anti-Alzheimer action was characterized by inhibiting of the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The anti-lipase test was used to evaluate the inhibitory capacity against pancreatic lipase. In addition, the photoprotective effect was estimated by determining in vitro sun protection factor (SPF) of F. bruguieri extracts. The results showed that polar extracts exhibited excellent antioxidant activity in various systems, with the best performance of butanol extract. The butanol extract contains a significant amount of phenolics and flavonoids (444.49 ± 0.84 mg GAE/mg and 266.45 ± 0.44 mg QE/mg, respectively). The petroleum ether extract shows a potent AChE and BChE activity with IC 50 = 27.41 ± 1.03 mg/mL and 46.14 ± 0.78 mg/mL, respectively. Concerning the anti-lipase effect, dichloromethane extract showed a strong inhibition against the lipase enzyme. In addition, F. bruguieri exhibited high photoprotective activity for absorbing UV radiations with SPF index ranging from 11.25 ± 0.1 to 43.86 ± 0.12. These findings suggest that F. bruguieri extracts provide a valuable source of antioxidants that can be explored in multiple therapeutic remedies and can be used for the prevention of Alzheimer's disease and as anti-obesity agent. Extracts of F. bruguieri DC can also be used to treat skin conditions as cosmetic formulations and in the pharmaceutical industry.
... stephensi, however, it could not efficiently inhibit AChE [141,164]. In contrast, the epoxide form of pulegone, the pulegone-1,2-epoxide isolated from the Lippia steochadifolia EO, has be reported to be an insect neurotoxin, acting as an irreversible inhibitor of AChE [191]. In addition, the Citrus limon EO and it major EOC, limonene (99%) both possess weak AChE inhibition properties; whilst both are potent larvicides against An. ...
The insect nervous system is critical for its functional integrity. The cholinergic system, of which acetylcholinesterase (AChE) is a key enzyme, is essential to the Anopheles (consisting of major malaria vector species) nervous system. Furthermore, the nervous system is also the primary target site for insecticides used in malaria vector control programs. Insecticides, incorporated in insecticide-treated nets and used for indoor residual spraying, are a core intervention employed in malaria vector control. However, Anopheles resistance against these insecticides has grown rapidly. Due to this major setback, novel agents with potential activity against resistant Anopheles and/or capacity to overcome resistance against current WHO-approved insecticides are urgently needed. The essential oils have the potential to be natural sources of novel insecticides with potential to inhibit the Anopheles AChE target. In the current review, the scientific evidence highlights the ability of essential oils and specific essential oil constituents to serve as anticholinesterase insecticides. For this reason, the published data from scientific databases on the essential oils and essential oil constituents on anticholinesterase, ovicidal, larvicidal, pupicidal and adulticidal activities were analyzed. The identification of major constituents in active essential oils and their possible influence on the biological activity have also been critically evaluated. Furthermore, the toxicity to mammals as well as potential activity against the mammalian AChE target has also been reviewed. The importance of identifying novel potent insecticides from essential oils has been discussed, in relation to human safety and cost-effectiveness. Finally, the critical insights from this review can be used to inform future researchers towards potent and safe anticholinesterase insecticides for the management of Anopheles malaria vectors.
... Mode of action of the major insecticides involve mainly in the nervous system, especially inhibition of acetylcholinesterase, an enzyme of critical importance in the transmission of nerve impulse [26]. The measurement of the activity of acetylcholinesterase in red cotton bugs exposed with bioinsecticide was carried out in this perspective. ...
Cotton, the most important fiber crop of India plays a dominant role in its agrarian and industrial
economy. Pest management approach of varying degrees of sophistication has been applied for insect control in all
cotton-producing areas of our country. During the coevolution of plants and insects, plants have biosynthesized a number
of secondary metabolites to serve as defense chemicals against insect attack. Plants appear to produce a wide variety of
secondary metabolites as defensive weapons. Such defensive chemicals are far superior to the synthetic pesticides. It
concludes that the isolated polyphenolic biopesticide from Streblus asper (PBSA) was found to have noteworthy
insecticidal activity to Dysdercus cingulatus (red cotton bug) with an LD50 of 0.894 µg/insect by residual film technique
and 0.595 µg/insect by topical application. Significant inhibition in activities of acetylcholine esterase (AChE) lead to the fact that
Dysdercus cingulatus become more susceptible to the tested biopesticides. The present study has provided some basic
information on the mechanism of insecticidal action of polyphenolic compound that will be useful to the development
better management strategies. This may provide a useful beginning for the development of eco- friendly biopesticides.
... Furthermore, several studies have established that essential oils from aromatic plants inhibit acetylcholinesterase (AChE) in different insect species [55][56][57]. AChE plays a role in cholinergic synapses that are essential for insects and higher animals [58]. Inhibition of AChE leads to a high deposit of acetylcholine at the synapses. ...
Simple Summary
Mosquitoes are vectors of many severe diseases, notably malaria, yellow as well as dengue fever, and lymphatic filariasis. Vector control with synthetic chemical insecticides has been associated with resistance development and undesirable human and ecological effects. Ocimum kilimandscharicum oil formulation was evaluated for larvicidal activity against third instar mosquito larvae in the laboratory. The formulation was then compared with Bacillus thuringiensis subsp. israelensis (Bti) granules on An. gambiae larvae under field-simulated field trials. The LC50 for O. kilimandscharicum oil after 24 h against third instar larvae of An. gambiae was 0.74 ppm while for the emulsified O. kilimandscharicum oil formulation against third instar larvae of An. gambiae and An. arabiensis was 0.07 and 0.31 ppm, respectively. The high bioactivity and sublethal toxic effects to offspring of treated mosquito larvae in terms of the disruption of larval morphological aspects suggest its high potential as a botanical larvicide for the control of disease vectors. The bioactive formulation had the advantage of high solubility in aqueous media; it is also easily produced, ecofriendly, and low-cost. Moreover, because O. kilimandscharicum can easily be widely cultivated and has high EO yields, it may provide a valuable alternative for the effective and eco-friendly control of disease vectors among developing and developed communities.
Abstract
Mosquitoes are vectors of many severe diseases, including malaria, yellow as well as dengue fever, and lymphatic filariasis. The use of synthetic chemical insecticides for mosquito control has been associated with resistance development and detrimental human, and ecological effects. For a safer alternative, the emulsified Ocimum kilimandscharicum oil formulation was evaluated for its larvicidal activity. The oil was analyzed by GC and GC/MS. The formulations were evaluated against third instar mosquito larvae in the laboratory and later compared with Bacillus thuringiensis subsp. israelensis against An. gambiae under field-simulated conditions. Thirty-nine compounds were identified in the oil, the main ones being D-camphor (36.6%) and limonene (18.6%). The formulation showed significant larval mortalities against An. gambiae and An. arabiensis larvae with LC50 of 0.07 and 0.31 ppm, respectively, at 24 h. Under the field-simulated trial, within 24 h, the formulation showed 98% mortality while Bti had achieved 54%. On day three, it caused 100% mortality while Bti achieved 76.5%. The high bioactivity and sublethal toxic effects to offspring of treated mosquito larvae, in terms of disruption of larval morphological aspects, suggest the high potential of the formulation as a botanical larvicide. The formulation, thus, may provide a valuable alternative for the effective and eco-friendly control of disease vectors.
... Therefore, hypotheses suggested for the mechanisms of EOs components' nematicidal activity were generally based on pharmacological effects observed in insects [6]. Several EOs monoterpenes were demonstrated as competitive inhibitors of acetylcholinesterase isolated from different insect species [41,42], while other studies also documented a functional disruption of detoxifying systems in insects by EOs' compounds such as thymol, eugenol, pulegone, terpineol, and citronellal [43,44]. The octopaminergic system, as playing a key role as a neurotransmitter, neurohormone, and neuromodulator in invertebrate systems, was also indicated as a target of the action of EOs constituents in insects [45,46]. ...
Essential oils (EOs) from lavandin are known for a large spectrum of biological properties but poorly and contrastingly documented for their activity against phytoparasitic nematodes. This study investigated the toxicity of EOs from three different lavandin cultivars, Abrialis, Rinaldi Cerioni, and Sumiens, either to juveniles (J2) and eggs of the root-knot nematode Meloidogyne incognita and to infective stages of the lesion nematode Pratylenchus vulnus. The suppressive activity of treatments with EOs from the three lavandin cultivars in soil infested by M. incognita was also investigated in a greenhouse experiment on potted tomato. The compositional profiles of tested EOs were also analyzed by GC-FID and GC-MS. Linalool was the major component of all the three EOs, as accounting for about 66%, 48%, and 40% of total EO from cv Rinaldi Cerioni, Sumiens, and Abrialis, respectively. Linalool acetate was the second most abundant compound in the EOs from cv Abrialis (18.3%) and Sumiens (14.9%), while significant amounts of camphor (11.5%) and 1,8-cineole (12.1%) were detected in cv Rinaldi Cerioni and Sumiens EOs, respectively. The mortality of M. incognita J2 peaked 82.0%, 95.8%, and 89.8% after a 24 h treatment with 100 mg·mL⁻¹ solutions of cv Abrialis, Rinaldi Cerioni, and Sumiens EOs, respectively. Infective specimens of P. vulnus were largely more sensitive than M. incognita J2, as there were peak mortality rates of 65.5%, 67.7%, and 75.7% after 4 h of exposure to Abrialis, Rinaldi Cerioni, and Sumiens EO, respectively. All three lavandin EOs significantly affected also M. incognita egg hatchability, which reduced to 43.6% after a 48 h egg mass exposure to a 100 µg·mL⁻¹ solution of cv Rinaldi Cerioni EO. Soil treatments with the three lavandin EOs strongly reduced, according to a dose–effect relationship, density of M. incognita eggs, and J2 both on tomato roots and in soil, as well as significantly reduced gall formation on tomato roots. Finally, almost all soil treatments with the lavandin EOs also resulted in a positive impact on tomato plant growth.
... Acetylcholinesterase (AchE, EC 3.1.1.7) is a key enzyme for catalyzing the hydrolysis of acetylcholine, a neurotransmitter, in the nervous system (Grundy and Still, 1985;Wang et al., 2004;Zibaee, 2011). AchE is primarily responsible for the termination of cholinergic neurotransmission at synapses in both insects and human (Fournier and Mutero, 1994;Carlier et al., 2008). ...
... A common structural feature of terpenoids is their hydrocarbon skeleton, which in turn renders them hydrophobic. (Grundy and Still 1985). Five other monoterpenoids were similarly tested for their effects on AChE, and comparative results suggested that both the epoxy and keto groups are required for irreversible inhibition. ...
The contact toxicity, fumigant and oviposition deterrent activities of the essential oils from four plant species, geranium (Pelargonium graveolens), aniseed (Pimpinella anisum), German chamomile (Matricaria chamomilla) and Bitter orange bigarade (Citrus aurantium) were evaluated against Callosobruchus maculatus adults. Residue contact toxicity assayed by exposure of insect adults to thin film of oil in Petri dish showed that, at 24 h of treatment, P. graveolens oil was the most effective (LC50 = 3.5 mg/L) followed by P. anisum oil (LC50 = 4.9 mg/L). However, in the fumigation assay, after 24 h exposure, the LC50 values demonstrated that the most effective essential oils were P. graveolens (29.4 mg/L air) followed by P. anisum (50.0 mg/L air), and C. aurantium 79.38 mg/L air. The fumigant toxicity increased with increasing in exposure periods. The time needed for the essential oil to cause LT50 (median lethal time) was also estimated at the highest concentration used (2000 mg oil per kg cowpea seeds). Based on LT50 values, it was shown that C. aurantium oil was the most toxic material against insect LT50 = 10.24 hrs) followed by oils of P. anisum and M. chamomilla (LT50s were 19.5 h and 16.2 h, respectively). In addition, oviposition potency of C. maculatus was reduced significantly when insect adults were exposed to cowpea seeds mixed with sublethal concentrations of test oils. At the lowest concentration used (250 mg/kg), C. aurantium and Pimpinella anisum oils appeared to be the most effective in reducing oviposition rates compared to the control. With respect to the number of F1- progeny produced, the C. aurantium, P. anisum and M. chamomilla oils significantly reduced F1-progeny emergence compared to the control treatment. The chemical constituents of essential oils extracted from the four plant species used were also determined. The results suggested that these essential oils can be used as appropriate alternative to control of cowpea seed beetle.
... Asian varieties of A. calamus contain varying amounts of betaasarone and cause sedative effects when ingested, and also possess anti-gonadal activity against some insect species [12,13] . Monoterpene hydrocarbons, also an active component of sweet flag, are competitive inhibitors of acetylcholinesterases, which are neurotoxic to insects and plant diseases like Rice Blast [14,15] . A similar result was also proposed by Panthee (1997) and suggested that A. calamus treated maize seed produce lower weevil population compared with other treatments such as neem, Malabar nut tree, mugwort treated seeds [16,17] . ...
... Cet effet neurotoxique serait lié aux composés monoterpéniques contenus dans les deux huiles essentielles testées. Cet argument a été évoqué par plusieurs autres auteurs pour expliquer l'effet des huiles essentielles à travers leurs composés terpéniques qui agiraient sur les insectes comme des neurotoxines Huignard et al., 2002 ;Enan, 2001 ;Keane et Ryan, 1999 ;Karr et al., 1990 ;Ryan et Byrne, 1988 ;Grundy et Still, 1985). Selon Keane et Ryan (1999) (Smith et Salked, 1966 ;Michaelides et Wright, 1997). ...
Diplôme : Dr. d'Université
... Monoterpenes act as neurotoxicants against different insect species (Coats et al., 1991;Enan, 1998). Monoterpenes have been shown to inhibit both GABA receptor (Coats, 1990) and acetylcholinesterase (AChE) (Grundy and Still, 1985;Ryan and Byrne, 1988). It was also reported that monoterpenes may inhibit cytochrome P450-dependent monooxygenases (De-Oliveira et al., 1997). ...
... However, previously similar signs have been described by insects upon exposure to pure monoterpenes ( Coats et al., 1991). Some monoterpenes alter the physiological functions by competitive inhibition of acetylcholine esterase in houseflies and cockroaches (Grundy & Still, 1985;Ryan & Byrne, 1988). The toxic effects exerted by EO of L. nobilis could be attributed to the toxic constituent like eugenol, linalool, myrcene and other phenolic compounds present therein. ...
Background
The synanthropic housefly, Musca domestica , augments the transmission of several detrimental diseases like cholera and avian flu. Consequently, during the last century, many physico-chemical methods including synthetic compounds have been applied for its control. But these methods have proven to be prohibitive due to their side effects and serious issues like resistance development, environmental contamination, and detrimental effects on non-target fauna. Therefore, in view of these objectives, we investigated the effects of bay essential oil (EO) against M. domestica .
Methods
The attractant/repellent assays were conducted by double choice technique. Different enzyme assays evaluating the effect of LC 50 concentration of the tested essential oil on larval gut were taken into consideration. To determine the composition, the tested oil was subjected to GC-MS/MS analysis. Further, the morphological alterations caused by EO treatment to third instar larvae were observed in a Nova Nano SEM machine. Data was statistically analyzed by one-way ANOVA using Tukey’s test ( p < 0.001). The LC 50 and LC 90 values were calculated by probit analysis.
Results
The adulticidal bioassay revealed significant effects with LC 50 concentration as 43.03 mg/dm ³ against the newly emerged adult flies while in larvicidal assay mortality was dose dependent showing maximum effect at LC 50 0.0629 μg/cm ² . The pupicidal activity was more effective at a dose of LD 50 64.09 μl/0.25 L of air which either killed the pupae or caused deformity in the emerged adults. Likewise total sugar, protein, glycogen, and lipid contents of larvae were reduced after treatment with EO when compared with the normal larvae along with some gut enzymes. The EO reduced the acetylcholinesterase activity from 0.013 U/mg protein in normal larvae to 0.0093 U/mg protein after EO treatment. The GC-MS/MS analysis of the bay EO showed the abundance of myrcene, linalool, eugenol, chavicol, and anethole along with diterpenoid, geranylgeraniol. However, the insecticidal activity of tested EO might be majorly imparted by eugenol content. The FESEM analysis showed shrinkage of integument and distortion to intersegmental regions caused by the tested compound.
Conclusion
The present study concludes the significant efficacy of bay EO against M. domestica which could be employed to breakdown its population below threshold levels to prevent the menace of vector-borne diseases.
... This tricyclic sesquiterpene acts as an antagonist of the ɤ-aminobutyricacid (GABA) system, more specifically on chloride receptor channels (Bloomquist et al., 2008). Another compound with neurotoxic activity is the monoterpenoid pulegone-1, 2-epoxide, isolated from Lippiasteochadifolia (Grundy & Still, 1985). The authors demonstrated that this compound acts like carbamates, irreversibly inhibiting the enzyme acetylcholinesterase. ...
Chemical control of leaf-cutting ants is widely used, but alternative control with toxic plant extracts is promising. Substances with insecticidal potential extracted from plants have numerous ecological advantages. This study evaluated the insecticidal and/or fungicidal potential of the plants Asclepias curassavica (tropical milkweed), Rosmarinus officinalis L. (Lamiaceae) (rosemary) and Equisetum spp. (horsetail) for control of the leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae). Forty laboratory-reared colonies of Atta sexdens rubropilosa were used. The plants were collected, dried out in a circulating air oven for 48 hours, ground, and macerated in 96o ethanol until exhaustion. After filtration, the products were evaporated under reduced pressure to obtain the ethanolic extracts. Acceptance of the reagent, topical application of the extracts, and application of baits containing 4% of the plant extracts were tested. The results showed that all plant extracts tested negatively influenced the development of the fungus garden. Baits produced with Asclepias curassavica caused the highest mortality of the colonies within 7 days. In conclusion, the ethanolic extracts of Asclepias curassavica, Rosmarinus officinalis and Equisetum spp. exhibit insecticidal (contact and ingestion) and fungicidal activity in colonies of the leaf-cutting ant Atta sexdens rubropilosa.
... Consequently, we postulated that several metabolites in Mexican oregano oil had a synergic effect. Monoterpene compounds are neurotoxic against different insect species and inhibit activity of acetylcholinesterase (Grundy and Still 1985). Oils might cause insecticidal activity by one or more modes of action (El-Aziz and El-Sayed 2009). ...
... and insecticidal effects (Pavela 2005). This plant contains chemical substances like alkaloids, monoterpenes, glycosides, saponins, tannins, flavonoids and phenolic compounds (Jain et al. 2012), and especially pulegone and menthone (Grundy and Still 1985), conferring it a wide range of biological properties including antifeedant, insecticidal. Oviposition deterrent, contact toxicity and insect growth regulation (Raja et al. 2005;Khanna and Kannabiran 2007;Baskar et al. 2010). ...
This study investigates the insecticidal effect of the essential oil of Mentha pulegium L. on the second and third instar larvae of Helicoverpa armigera (Hübner). Antifeedant, contact toxicity and systemic toxicity of M. pulegium essential oil were evaluated using four concentrations and an untreated control under laboratory conditions. M. pulegium essential oil showed high level of antifeedant activity at 74.15%, and 61.72% when applied on the second instar larva and third instar larvae, respectively. The second instar larva was also more susceptible to systemic toxicity than the third instar larva LC50 1.80% and 3.80% at 24 h, respectively. Contact toxicity induced with LC50 values of 1.31% and 1.085% after 3 and 6 h on the second instar larva, respectively, and with LC50 values of 2.39% and 2.33% after 3 and 6 h on the third instar larva, respectively. This study showed that there is potential for using M. pulegium essential oil to formulate a biopesticide for the control of H. armigera larvae on chickpea.
... In vivo inhibitory effects of δ-3-carene were less evident than in vitro results. Other authors (Grundy and Still, 1985) reported that increasing exposure times of roaches to pulegone (a potent AChE in vitro inhibitor) lead to progressive development of symptons and insect death but this was not correlated with a decrease in AChE activity in vivo. This is maybe a consequence of the monoterpene being metabolized before it reaches the insect brain or that the insect synthesizes more enzyme after the treatment (Perry et al., 2000). ...
... α-Terpeneol and terpinene-4-ol have fumigant toxicity to S. oryzae [19]. The essential oils and their constituent monoterpenoids might act as neurotoxins [36]. Although the toxic effects of oil constituents used in the study have not been thoroughly investigated against humans and other mammals, available data for the use of plant materials containing monoterpenoids as pharmaceuticals and flavourings indicated no health side effects of their use. ...
Introduction: Potato ( Solanum tuberosum L.) is an important vegetable crop in Syria. Potato tuber moth Phthorimaea operculella is the main damaging pest of this crop. Many approaches were tried to control it.
Objectives : This study evaluates the insecticidal activity of Juniperus foetidissima essential oil and two monoterpenes against potato tuber moth using fumigation bioassays.
Methods: Essential oil was extracted from new plant branches of Juniperus foetidissima using Clevenger-type apparatus. Potato tuber moth Phthorimaea operculella , (adults, eggs, larvae, and pupae) were exposed to different concentrations of the essential oil of Juniperus foetidissima for various periods. The significance of differences between treatments at p <0.05 were evaluated by one-way analysis of variance using the mortality percentages data. The LC 50 and LC 90 were calculated by Probit analysis.
Results : Essential oil vapor with LC 50 : 0.3 μ l/l air was very effective against potato tuber moth at the adult stage. However; adults sensitivity to monoterpenes varied: Nerol caused a 100% mortality at 0.025 μ l/l air after 6 h, while the same concentration of citronellol caused 98% mortality. The 0.125 µ l/l air concentration of the two compounds caused 100% mortality after 6 h.
Conclusion: Results suggest the possibility of using Juniperus foetidissima essential oil as a fumigant to control potato tuber moth infestation in stores.
... Several reports indicate that monoterpenoids cause insect mortality by inhibiting acetylcholinesterase enzyme (AChE) activity (Houghton et al., 2006). However, with some monoterpenes, inhibition was noted in in vitro tests but not in vivo in insects (Grundy and Still, 1985). In a comparative study on the fumigant action of terpenes (ZP51 and SEM76) from Labiatae plants and (+)limonene, a component of plant essential oil, on AChE activity as well as octopamine systems in R. dominica adults, Kostyukovsky et al. (2002) noted that AChE inhibition was highest (65%) for highly toxic ZP51 but moderate for SEM76 (27%) and it was very low for (+)limonene (2%) that was least toxic. ...
... Previously, Coats et al. 57 reported hyperactivity and leg tremors as common poisoning symptoms associated with essential oil constituents. In the Madagascar cockroach (Gromphadorhina portentosa), pulegone-1,2-epoxide (an essential oil component) caused hyperactivity and muscular spasms before eventual paralysis and death 58 . In general, neuroinhibitory insecticides (e.g., oxadiazines and avermectins) are known to cause flaccid paralysis, wherein the muscles become limp and are unable to contract due to reduction or loss of nerve activity 40,59 . ...
Bed bugs (Cimex lectularius L.) are globally important human parasites. Integrated pest management (IpM) approaches, which include the use of essential oil-based insecticidal compounds, have been proposed for their control. This study aimed to define insecticidal activity and neurophysiological impacts of plant essential oil constituents. The topical and fumigant toxicity of 15 compounds was evaluated against adult male bed bugs. Neurological effects of the 6 most toxicologically active compounds were also determined. In both topical and fumigant bioassays, carvacrol and thymol were the most active compounds. the potency of bifenthrin (a pyrethroid insecticide) in topical bioassays was 72,000 times higher than carvacrol, while vapors of dichlorvos (an organophosphate insecticide) were 445 times more potent than thymol. Spontaneous electrical activity measurements of the bed bug nervous system demonstrated neuroinhibitory effects of carvacrol, thymol and eugenol, whereas linalool produced an excitatory effect. Although citronellic acid and (±)-camphor increased baseline activity of the nervous system their effects were not statistically significant. Bifenthrin also caused neuroexcitation, which is consistent with its known mode of action. these comparative toxicity and neurological impact findings provide new information for formulating effective essential oil-based insecticides for bed bug IpM and conducting mode-of-action studies on individual essential oil components.
... Indeed, geraniol has been shown to have remarkable insecticidal and repellent activities against Sitophilus zeamais, is a genus of weevils (Reis et al. 2016). Certain essential oil monoterpenes may exert an in vitro competitive inhibitor effect on esterase enzyme family (Grundy andStill 1985, Miyazawa et al. 1997), but this action may not be correlated with in vivo toxicity to insects (Isman MB 2000). Enan (2001) suggested that using the octopaminergic nervous system is main target of a number of essential oil constituents as the site-of-action in insects. ...
In this study, the effect of geraniol (50 mg/kg for 30 d), a natural antioxidant and repellent/antifeedant monoterpene, in a rat model of lead acetate-induced (500 ppm for 30 d) liver damage was evaluated. Hepatic malondialdehyde increased in the lead acetate group. Reduced glutathione unchanged, but glutathione S-transferase, glutathione reductase, as well as carboxylesterase activities decreased in geraniol, lead acetate and geraniol + lead acetate groups. 8-OhDG immunoreactivity, mononuclear cell infiltrations and hepatic lead concentration were lower in the geraniol + lead acetate group than the lead acetate group. Serum aspartate aminotransferase and alanine aminotransferase activities increased in the Pb acetate group. In conclusion, lead acetate causes oxidative and toxic damage in the liver and this effect can reduce with geraniol treatment. However, we first observed that lead acetate, as well as geraniol, can affect liver carboxylesterase activity.
... Essential , 2000). Certain essential oil monoterpens are competitive inhibitors of acetylcholinesterase enzyme (AChE) activity (Grundy and Still., 1985;Miyazawa et al., 1997 This Cotton worm is one of the most destructive agricultural lepidopteron pests within its subtropical and tropical range. It is attacking plants belonging to a large range of families including grasses, legumes, crucifers and deciduous fruit trees all containing species of highly economic importance. ...
Chemical pesticides are still the most effective means for the protection against pests. However, repeated use of those pesticides for decades has disrupted biological control by natural enemies and cause enormous damage for consumers and environment. As part of an effort aimed to the development of reduced risk of chemical pesticides, essential oil of Euginia carpophyllata (Myrtaceae) was found to prossess strong insecticidal activity against the mediterrannean climbing cutworm; Spodoptera littoralis. Essential oil of E. carpophyllata was obtained from hydrodistillation and was analyzed by GC-MS in order to identify their chemical composition. The main components of essential oil were; a propenylphenolique compound Eugenol (52.82%) and other terpene compounds such as β-Caryophyllene (30.26%), α-Humulene (6.11%) and Eugenyl acetate (2.51%). Different concentrations of the oil were tested and the observed larvae mortality showed high fumigant toxicity against the third instar of S. littoralis larvae with a DL 50 value of 7.81µl/l air and DL 90 value of 17.97µl/l air. RÉSUMÉ Les insecticides chimiques sont généralement les plus utilisés pour la lutte contre les ravageurs des denrées stockées. Néanmoins, ils peuvent provoquer d'énormes dégâts pour le consommateur et l'environnement, ce qui a favorisé l'essor rapide des solutions alternatives. C'est dans ce contexte que s'inscrit le présent travail qui vise à déterminer la composition chimique des huiles essentielles de girofle et à étudier ses activités bio-insecticide. Les huiles essentielles de girofle ont été extraites par hydrodistillation. Ensuite, elles ont été analysées par CG-SM afin de déterminer leur composition chimique. Finalement, un test de fumigation a été réaliser contre Spodoptera littoralis afin d'étudier leur pouvoir bio-insecticide. Les résultats trouvés montrent que les huiles essentielles sont composées majoritairement d'un composé propénylphénolique : l'Eugénol à 52.82%, ainsi que d'autres composés terpéniques tels que ß-Caryophyllene (30.26%), α-Humulene (6.11%) et Eugenyl acétate (2.51%). Le test de fumigation a montré la mort des larves de 3 ème stade de Spodoptera littoralis. Les mortalités sont toutefois proportionnelles aux doses. Le calcul des concentrations létales par la méthode Probit a montré que la CL 50 = 7.81 µl/l d'air et la CL 90 =17.97µl/l d'air. Grâce à leurs compositions, les huiles essentielles d'Eugenia caryophyllata, présentent un fort potentiel bio-insecticide à l'égard de S.littoralis. D'où la possibilité de leurs implication dans des formulations phytopharmaceutiques utilisées comme alternatives aux pesticides chimiques.
... This valuable natural compound and its derivatives have considerable antihistaminic, antioxidant, hepatotoxic, antimicrobial, and avian repellent properties (Moorthy et al., 1989;Mason, 1990;Urbina et al., 1990;Tabatabaei-Anaraki et al., 2007). These compounds also possess significant inhibitory potential against acetylcholinesterases (Grundy and Still, 1985). ...
This review was undertaken because of the lack of a comprehensive review on the compositions of secondary metabolites, extracts and volatiles of Ziziphora species and of the biological activities of these materials. The Lamiaceae or Labiatae family comprises a large number of flowering plants of widespread distribution, which have been classified into some 236 genera and 6900–7200 species. The genus Ziziphora is one of the well-known genera of this large family of plants and its species are of prime importance in different fields of pharmaceutical, chemical, medicinal, traditional and folk medicines. This review is concerned with characterization of chemical profiles of essential oils, extracts and volatiles, along with relevant biological and phytochemical properties of a wide spectrum of plants in this genus over the 46-year period, 1970–2016. These reports demonstrate the significant impact of these herbal and medicinal plants for the treatment of a variety of diseases and as effective alternative options for chemical drugs which sometimes have unpleasant side effects.
... An enzyme extract containing acetylcholinesterase (AChE) was obtained per the method of Grundy and Still (1985). About 100 adults of the insect S. frugiperda were frozen at À20 C for 7 days. ...
... Plant essential oils may be an alternative source of new compounds for mite control in greenhouses because they are volatile chemicals mostly non toxic to mammals, birds and fish, and are commonly used as &agrances and flavoring agents for food and beverages. Furthermore, they act against insects and mites via neuro-toxic effects by which they affect octopamine pathways and GABA' Gated chloride ion channels ( Grundy& Still, 1985;Enan,200l). The lack of octopamin receptors in vertebrates likely accounts for the profound mammalian selectivity of essential oils as insecticides (Kostyukovskyet,al., 2002). ...
... Silwett surfactant at concentrations of 0.1 to 0.5% increased the mortality of Tetranychus pacificus eggs in laboratory studies by more than 99% [26] . It is possible that as monoterpenoids act against insects as neurotoxins [27,28,29] , ovicidal activity is only apparent when the target system (the nervous system in this case), begins to develop [30,31] . ...
An ionic liquid 3-(2-((3,7-dimethyloct-6-en-1-yl)oxy)-2-oxoethyl)-1-methyl-1H-imidazol-3-ium chloride was synthesized by simple esterification of citronellol with chloroacetic acid and tested for its insecticidal properties. The present work also includes the comparative account of insecticidal activities of citronellol, ionic surfactant and a nonionic surfactant. The ionic surfactant at concentrations of 5 and 10 µL showed 68 to 88% mortality in Callosobruchus analis F. and 63 to 76% in Sitophilus oryzae L. respectively after 24 hours of treatment. Both the surfactants significantly deterred the majority of females of C. analis from laying eggs on treated seeds than control. The ionic surfactant was most effective in reducing Fl progeny production by causing 96% progeny deterrence followed by 87% progeny deterrence in citronellol. The citronellol and ionic surfactant showed strong inhibition on egg hatchabilities of C. analis even at the lowest concentration. Antifeedant activity evaluated for S. oryzae adults by calculating relative growth rate (RGR), relative consumption rate (RCR), efficiency on conversion of ingested food (ECI) and feeding deterrence indices (FDI), showed increased antifeedant action with increasing doses of all the three compounds.
... Silwett surfactant at concentrations of 0.1 to 0.5% increased the mortality of Tetranychus pacificus eggs in laboratory studies by more than 99% [26] . It is possible that as monoterpenoids act against insects as neurotoxins [27,28,29] , ovicidal activity is only apparent when the target system (the nervous system in this case), begins to develop [30,31] . ...
Research article ..................................................
... Our results showed a richness of oxygenated monoterpenes in T. articulata and J. phonicea essential oils, which in our research appeared to possess a strong toxicity against A. citricola. Essential oils containing monoterpenes can inhibit acetylcholinesterase [31,32], Octopamine [33,34], or monooxygenases' cytochrome P450 [35]. Many of these essential oils act at the neurotransmitter Octopamine level, which is specific to invertebrates, and as such they are less toxic in general to mammals orally [36]. ...
Les pucerons provoquent des dégâts important sur les cultures dont les agrumes. Pour faire face à ces ravageurs, les agriculteurs utilisent des pesticides de synthèse. Toutefois, ces derniers ont des effets négatifs sur l’environnement. Afin de trouver de nouveaux composés efficaces contre les pucerons en particulier Aphis citricola et non nocifs à l'environnement, la toxicité des huiles essentielles des rameaux feuillés de Tetraclinis articulata et Juniperus phoenicea a été évaluée contre A. citricola. L’extraction des huiles essentielles a été réalisée par hydrodistillation et leur composition chimique analysée par la CPG/SM. Trente-six composés de l’huile essentielle de Tetraclinis Articulata, ont été identifiés; l’acétate de bornyle (30,74 %), l’α-pinène (23,54 %), le camphre (17,27 %) et le limonène (23,31 %) constituent les principaux composés de cette huile. pour l’huile essentielle de Juniperus phoenicea, quarante-sept composés ont été identifiés ; le composé majoritaire est α-pinène avec un pourcentage de 48.18%, vient par la suite ; δ- Cadinene (6.61 %). Les huiles essentielles testées se sont montrées toxiques vis-à-vis Aphis citricola. La toxicité de ces huiles s’amplifie avec la concentration et le temps et elle varie selon la plante. L’huile essentielle des rameaux feuillés de Juniperus phoenicea a été le plus toxique vis-à-vis d’A. citricola et ses composés peuvent être des nouveaux agents de contrôle biodégradables contre les pucerons qui peuvent être utilisé dans un système de gestion intégrée contre les ravageurs.
... I retention index, MS mass spectrum, Co-GC co-injection with authentic compound. Monoterpenes present in EOs were reported to act by a reversible competitive inhibition on acetylcholinesterase in house fly, cockroach (Grundy & Still 1985, Ryan & Byrne 1988, Miyazawa et al 1997), and stored product insects (Kostyukovsky et al 2002). In addition, visible symptoms, such as hyperactivity, convulsions, and tremors, followed by paralysis indicated a neurotoxic mode of action for these molecules (Coats et al 1991, Abdelgaleil et al 2009). ...
... 81 (1S)-Configured pulegone, menthone and isomenthone may serve as appropriate indicators in the authenticity control of buchu leaf oil as well as "cassis" type fruit aromas and fragrances. 82 Toxicological observations indicate that pulegone is an insect neurotoxin, 83 as well as an abortifacient in women and in animals. 84 (1S)-( − )-Pulegone is far less toxic in mice than (1R)-(+) pulegone (both hepatotoxic and pneumotoxic). ...
... Our results showed a richness of oxygenated monoterpenes in T. articulata and J. phonicea essential oils, which in our research appeared to possess a strong toxicity against A. citricola. Essential oils containing monoterpenes can inhibit acetylcholinesterase [31,32], Octopamine [33,34], or monooxygenases' cytochrome P450 [35]. Many of these essential oils act at the neurotransmitter Octopamine level, which is specific to invertebrates, and as such they are less toxic in general to mammals orally [36]. ...
Aphids cause significant damage tp crops, particularly citrus. To combat these pests, farmers typically use synthetic pesticides, yet these pesticides leave negative impacts on the environment. In an effort to find new efficient forms of control against aphids, especially Aphis citricola, without causing damage to the environment, we evaluated the toxicity of essential oil from the leafy twigs of Tetraclinis articulata and Juniperus phoenicea. Essential oil extraction was performed by steam distillation, and chemical composition was analyzed by gas chromatography–mass spectrometry (GC–MS). Thirty-six components were identified in the essential oil from T. articulata. Isobornyl acetate (58.32 %), α-pinene (9.31 %), and camphor (9.23 %) are the main components of this oil. For J. phoenicea, forty-seven compounds were identified; α-pinene was the major compound at 48.18 %, followed by δ-cadinene (6.61 %). Each of the essential oils we tested showed some degree of toxicity against A. citricola. This toxicity is amplified with concentration and time, and varies between plant species. Ultimately, the essential oil extracted from J. phoenicea’s leafy twigs was the most toxic (54.03 μL/L after 24 h) against A. citricola; its compounds may therefore be considered as new biodegradable agents to control aphids and viable for use in an integrated pest management program.
... Essential oils of botanical origin and their major components, often their various monoterpenoids have attracted attention in recent years as potential pest control agents. Due to their insecticidal, repellent and/or antifeedant properties (Amos et al., 1974;Grundy and Still, 1985;Shaaya et al., 1997;Lee et al., 2003;Ketoh et al., 2005, Rozman et al., 2007Cosimi, et al., 2009 andShehawy, 2010 ). Also, some natural plant compounds used in the control of insect pests are known to influence the enzymatic profiles (Nathan, et al., 2005). ...
In order to search for new chemotypes and to carry out a comparative study with the literature, the current study investigated the chemical composition of the essential oil of the flowers of Daucus carota (L.) ssp. carota using gas chromatography coupled with mass spectrometry (GC-MS). Moreover, the antimicrobial and insecticidal potentials of essential oil were studied. Hydrodistillation was used to extract the essential oil. Due to the immiscibility of essential oils in water and, therefore, in the culture medium, emulsification was carried out using a 0.2 % agar solution to promote germ/composite contact. Fumigation with the oil phase of the essential oil was carried out in airtight and transparent plastic boxes, with a capacity of 1 L as an exposure chamber to test the lightness of essential oils against adults of Sitophilus oryzae (L.). In each box, five Petri dishes were placed. Each replicate consisted of five adults of S. oryzae (L.). The essential oils were spread on Wathman filter paper and placed inside the exposure chamber. Mortality control was carried out by counting insect deaths from the first day of treatment until the death of all individuals. α-Pinene (22.2 %) was the major compound in the essential oil of the oil phase of D. carota (L.) ssp. carota followed by β-asarone (15.1 %), sabinene (12.4 %), and α-himachalene (10.1 %), as well as the crystallized phase containing β-asarone. In terms of antimicrobial activity, the essential oils showed significant inhibition of the six bacteria and seven molds studied at a concentration of 0.45 mg/mL. The essential oils were found to be highly effective against S. oryzae (L.). This approach can help reduce the amount of synthetic antibiotics applied and, therefore, decrease the negative impact of artificial agents, such as residues, resistance, and environmental pollution.
Calotropis procera has an important biological role in controlling pests and disease-spreading vectors. A search for biopesticide is a novel approach for reducing the risk and persistence of chemical and synthetic pesticides. Different parts of plants such as leaves, bark, roots, flowers, seeds, etc. are extensively studied by numerous authors for insecticidal properties; however, the outcomes are not available in compiled form. Efforts are done to compile the research done on its insecticidal properties in the past 20 years. The available data has been classified based on target insect taxonomical orders, plant part with details of different fractions of extract, their activity, insecticidal activity, dosage, and extent of lethality. Preliminary data on larvicidal, insecticidal, adulticidal, and LC50 were retrieved along with plant parts, solvent/solvent fraction detail, and insect details (taxonomical order, larva/adult, and stage of larva). Later the data was classified for each plant part extracted in each solvent/fraction with taxonomical order of insect, the dosage used, the lethality of the dosage, and author details.
En la mosca blanca Trialeurodes vaporariorum, plaga de importancia económica en hortalizas, su manejo con insecticidas sintéticos ha generado resistencia con efectos adversos para el ambiente. En la búsqueda de alternativas de manejo, se planteó esta investigación con el objetivo de cuantificar la repelencia de adultos con extractos crudos (metanol, etanol, diclorometano y hexano), aceites esenciales (AE) y compuestos mayoritarios de clavo y pimienta. En un vaso con 10 mL de agua, se colocó una hoja de tomate tratada a concentraciones de 1,0 a 0,000001 % y se introdujeron 20 adultos de 2 d de edad. Luego, de las 3 a las 72 h, se cuantificaron los adultos posados y por diferencia se determinó la repelencia. Los extractos crudos, AE y compuestos mayoritarios de clavo y pimienta repelieron entre 32,5 y 90,2 % la población de adultos de las 3 a las 72 h. Los AE de clavo y pimienta presentan mejor efecto repelente que los extractos crudos y compuestos secundarios, ya que lograron repeler de 46,2 a 100 %; el AE de clavo a la concentración de 1,0 % logró 100 % de repelencia a las 48 y 72 h y el AE de pimienta alcanza 97,5 % a las 72 h. En la práctica, se debe utilizar extracto crudo etanólico de ambas plantas a la concentración de 0,000001 % ya que logran repeler entre 38,7 y 87,5 % de adultos, de las 3 a las 72 h, y su efecto repelente persiste; además, es más fácil de conseguir, más seguro para el operador, distribuidor y consumidor; y está considerado en las normas de agricultura orgánica como solvente para la extracción de compuestos secundarios.
Most of the traditional strategies used for facing the management of insect pest and diseases have started to fail due to different toxicological issues such as the resistance of target organism and the impact on environment and human health. This has made mandatory to seek new effective strategies, which minimize the risks and hazards without compromising the effectiveness of the products. The use of essential oils, their components and semiochemicals (pheromones and allelochemicals) has become a promising safe and eco-sustainable alternative for controlling insect pest and pathogens. However, the practical applications of this type of molecules remain rather limited because their high volatility, poor solubility in water and low chemical stability. Therefore, it is required to design strategies enabling their use without any alteration of their biological and chemical properties. Oil-in-water nano/microemulsions are currently considered as promising tools for taking advantage of the bioactivity of essential oils and their components against insects and other pathogens. Furthermore, these colloidal systems also allows the encapsulation and controlled release of semiochemicals, which enables their use in traps for monitoring, trapping or mating disruption of insects, and in push-pull strategies for their behavioral manipulation. This has been possible because the use of nano/microemulsions allows combining the protection provided by the hydrophobic environment created within the droplets with the enhanced dispersion of the molecules in an aqueous environment, which favors the handling of the bioactive molecules, and limits their degradation, without any detrimental effect over their biological activity. This review analyzes some of the most recent advances on the use of emulsion-like dispersions as a tool for controlling insect pest and pathogens. It is worth noting that even though the current physico-chemical knowledge about these systems is relatively poor, a deeper study of the physico-chemical aspects of nanoemulsions/microemulsions containing essential oils, their components or semiochemicals, may help for developing most effective formulations, enabling the generalization of their use.
The human head louse, Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae) is an obligate ectoparasite of humans. The infestation with head lice is unpleasant and may cause itching, prurito and secondary skin infections due to scratching of irritated scalp. Chemical control of head lice has been based on a variety of insecticides, such as organoclorides (DDT and lindane), organophosphates (malathion), carbamaes (carbaryl), natural pyrethrins and pyrethroids (deltamethrin, permethrin, d-phenothrin). The overuse of these insecticides is limited due to the development of resistant head lice populations. Alternatives to conventional insecticides might be found in aromatic plants such as essential oils (EOs) and their monoterpenoids. Some of these natural products are repellents, adulticides and ovicidal against a wide variety of pests. The aims of the present thesis were: a) to establish the biological activity of the vapour phase of the essential oils and their main compounds obtained from aromatic plants of Argentina against eggs and adults of permethrin-resistant head lice; b) to analyzed the repellent activity of the essential oils; and c) to study the mechanisms involved in the mode of action and the role of the monooxygenases in the toxicity of the monoterpenoids against head lice.
Head lice were collected from from heads of infested children 3-13 yr old, using a fine toothed antilouse comb. Fourty nine essential oils were collected from in the spring season of 2003-2004 and 2006-2007 from different regions of Argentina. Twenty six monoterpenoids were purchased from Aldrich. Prior to the study of the insecticide effect of the essential oils, pediculosis percentage (evidence of at least one living head lice) was calculated, and the permethrin resistance levels of the studied populations. An enclosed chamber was employed to study the fumigant activity of EOs and their components against eggs and adults of head lice. This method allowed creating a saturated micro-atmosphere as a result of the evaporation of the essential or component. Adults and nymphs III were observed for evidence of knockdown every 5 min for 60 min. Then, time in minutes to knockdown of 50% of each unit’s subjects (KT50). With respect to the eggs, each set was exposed to the substances for 24 h and mortalitity data was recorded. Repellency of EOs and components was estimated in an experimental arena with two areas. The number of lice was recorded every 5 min and each experiment was completed within 1 h. Then, a repellency index (RI) was calculated. The inhibition of the acetylcholinesterase activity (AChE) was calculated by a spectrofotometric and kinetic method. First, the inhibition of the monoterpenoids against AChE from electric eel was measured. Then, the inhibition concentration at 50% (IC50) of the most effective monoterpenoid was recorded from either AChE from electric eel or homogenate of lice. Finally, head lice were exposed to the vapours of the most effective compound and to the organophosphate dichlorvos-DDVP-, a well known AChE inhibitor. To study the role of the monooxygenases in monoterpenoide degradation, adult insects were topicated at different piperonil butoxide (PBO) concentrations and then exposed to the vapours of the most effective monoterpenoide and DDVP.
The results showed that, in average, 29.7% of the anayzed children had lice, and with the girls being more infected than boys. The resistant ratios (RRs) of the studied populations of P.h.capitis varied from 28.57% to 71.42% (in comparison with the laboratory susceptible strain of P.h.humanus). There were no significant differences among the KT50 values of the different permethrin-resistant populations. These indicate that pyrethroid-resistance mechanisms were no affected by the toxicity of the EOs and monoterpenoids. About the fumigant activity of the EOs against postembryonic insects, 24 of the 49 studied (49%) oils were effective against permetrhin-resistant head lice. Of these EOs, the most effective were from the native aromatic plants like Cinnamomun porphyrium, Myrcianthes cisplatensis, Aloysia citriodora (chemotype 2), Myrcianthes pseudomato, KT50 values of 1.12, 1.29, 3.02 and 4.09 min; respectively. The mentioned oils were 9- to 20-fold more toxic than the studied EOs. The most effective monoterpenoids were 1,8-cineole and anisole, with values of 11.1 and 12.7m; respectively. They were followed by limonene, 1S-(-)-α-pinene, β-pinene, (+)-α-pinene, linalool, mentone, α-pinene, pulegone, β-myrcene and benzyl alcohol. The KT50 value of the positive control DDVP was 40.15 min, and was less effective than the three more toxic compounds like 1,8-cineole, anisole and limonene. A positive relationship was found between the KT50 values of the effective compounds and corresponding vapour pressures, suggesting that the more volatile the compounds, the more effective it was as a fumigant. With respect to the study of the genetically modified oils (eucalypt hybrids), it is important to show that fumigant activity of the hybrids Eucalyptus grandis X Eucalyptus camaldulensis and Eucalyptus grandis X Eucalyptus tereticornis was higher (KT50= 13.6 and 12.9 min; respectively) than that for pure species (KT50= 25.6, 31.3 and 35 min). Moreover, a significant correlation was found between KT50 data and % of 1,8-cineole in the essential oils. The toxicity of the eggs revealed that the most effective monoterpenoids were anisole, α-pinene, β-pinene, (+)-α-pinene, 1S-(-)- α-pinene, anethole, carvone, limonene, linalool and 1,8-cineole. It was in accordance with the pattern found in adult head lice.
The most repellent essential oil was from the exotic Mentha pulegium and it was not significantly more repellent than the positive control piperonal. The most repellent monoterpenoid was benzyl alcohol with a RI= 57.74%, followed by (-) menthol, mentone y (+)-menthol with RI values of 53.56, 39.23 and 36.45%; respectively. The studied lactones possessed similar repellent activity than the positive control.
Concerning the enzymatic activity of acetylcholinesterase from electric eel, there were significant differences among the 20 studied monoterpenoids, with the 1,8-cineole as the most inhibitor with a IC50=6x10-3M. Moreover, 1,8-cineole was an inhibitor of the AChE obtained from homogenate of head lice with a IC=7.7x10-2M. The study of the sintomatology of intoxication of the 1,8-cineole and DDVP, followed by the analyses of the inhibitory activity of AChE of lice revealed that 1,8-cineole inhibited 13% of the AChE while DDVP inhibited 80%. The analysis of OFM showed a relationship between the sublethal dose of PBO and the KT50 of the exposed head lice to the vapours of 1,8-cineole and DDVP.
Finally, it is important to note that it is the first study of toxicity and repellency of essential oils and their compounds obtained from aromatic plants of Argentina against permethrin-resistant head lice. Additionally, the results obtained in the present thesis bring new insight into the knowledge of the mode of action of the monoterpenoids over the acetylcholinesterase activity and the role of the monooxigenases in the degradation of the mentioned components.
The insecticidal action of Citrus sinensis essential oil (EO) (LC50 = 3.9 mg/dm3) against the house fly Musca domestica is reviewed with special emphasis on the process of detoxification and on the actual intoxication of the insect once it is fumigated with the EO. The first metabolic pathway of terpenes is the oxidation by P450, followed by a neurotoxic effect with characteristic features that make flies sensitive to these compounds. The same response was observed for the most abundant terpene of the C. sinensis EO, the (4R)(+)-limonene (LC50 = 6.2 mg/dm3). By comparing the activity of the EO with (4R)(+)-limonene, we propose an explanation of the enhanced activity of the first with respect to the compound. The toxicity of C. sinensis EO showed a second order response with the temperature, with a maximum at 26°C. The neurotoxic effect of C. sinensis and (4R)(+)-limonene was assayed on the enzyme acetylcholinesterase (AChE) activity and the biogenic amines levels were determined. (4R)(+)-Limonene showed a low activity against AChE, with an inhibitory percentage of 22.6% at 0.61 M (equivalent to 84 mg/mL). The levels of tyrosine, dopamine, tyramine and octopamine in M. domestica head after fumigation with the EO or (4R)(+)-limonene were analyzed by HPLC and compared with the corresponding levels of untreated flies. Fumigation with C. sinensis EO or (4R)(+)-limonene increased 8 times the levels of dopamine but they did not affect the concentration of octopamine compared with control flies. The level of tyrosine, the precursor molecule of dopamine, was enhanced 3.3 and 3.6 times when flies were submitted to both fumigants, respectively, indicating that terpenes affect the chemistry of the neurological system.
In the recent years multifunctional biocompatible materials based on poly-lactic acid (PLA) have gain great interest in biomedical applications for its biocompatibility in the human body. However, some PLA properties have to be enhanced such as its low crystallinity and its mechanical properties. The introduction of other materials to reinforce PLA matrix as well as the addition of active additives to reduce the microorganism growth on the final material has been also suggested to obtain a final material with active properties. The addition of 25 wt% of poly-3-hydroxybutyrate (PHB) into PLA matrix has shown a positive reinforcement effect by maintaining the biocompatibility of the final formulation. The use of natural terpene D-(+)-limonene (D- (+)-Lim) to improve the compatibility between two polymer matrixes has been also proposed. The introduction of citrus essential oil as a component in biocompatible polymeric matrices opens new perspectives for biomedical applications.
Acetylcholinesterase from an organophosphate-resistant strain of housefly exhibited a decrease in sensitivity to Rabon in vitro, to the extent of 206-fold for the soluble enzyme and 38-fold for the particulate. These effects upon the bimolecular reaction constant, ki, were due to a 573-fold decrease in affinity of the inhibitor for the soluble and 103-fold for the particulate enzyme, coupled with a small increase in reactivity.
Polyacrylamide gel electrophoresis of the 100,000g supernatant fraction of thoracic homogenates from the DDT S housefly strain separated five bands having acetylcholinesterase activity. Ferguson plots indicated that the three bands of slowest mobility constituted members of the heterologous-size isomer family described for the head enzyme. The two faster migrating bands appeared as electrophoretic artifacts of juxtaposition with a 3.6 S nonacetylcholinesterase component; in the absence of juxtaposition, a single form was characterized with identical molecular properties to the 5.3 S fundamental unit of head acetylcholinesterase. The kinetic properties of isolated forms were consonant with the molecular data and no major differences in Km values for acetylthiocholine were discovered between the thoracic and head enzymes. We suggest the preferential in vivo inhibition of thoracic acetylcholinesterase by organophosphate pesticides is unlikely the consequence of biochemical differences between the enzymes from the two regions.
A kinetic study was undertaken of housefly cholinesterase inhibition by two methyl- and two dimethylcarbamates. The constant determining the relative concentration of the reversible enzyme-inhibitor complex (K̄i) and the rate constants for carbamylation and decarbamylation were determined. Contrary to the situation described in the literature for electric eel cholinesterase, the decarbamylation constant is larger for the methylcarbamyl than for the dimethylcarbamyl enzyme. The fly-head cholinesterase appears to be more sensitive to the carbamates studied than bovine erythrocyte cholinesterase. The importance for the in vivo action of the constants determining inhibition and reactivation is discussed.
The metabolic fate of radiolabeled Diazinon, malathion, and methyl parathion was studied in three housefly strains, two of which were resistant to organophosphates. Rate differences between the strains in cuticle penetration, phosphorothionate oxidation, or phosphate hydrolysis did not appear to explain the resistance. The lesser in vivo cholinesterase inhibition in resistant than susceptible flies treated with the same dose of the organophosphate probably results from some other mechanism than detoxification. Flies treated with the organophosphate immediately after decapitation were similar to whole flies in the symptomology of poisoning and degree of resistance. Evidence is presented for a "factor" in the thorax and/or abdomen which contributes to resistance by reducing rate of cholinesterase inhibition without destroying active antiesterase organophosphate.
A photometric method for determining acetylcholinesterase activity of tissue extracts, homogenates, cell suspensions, etc., has been described. The enzyme activity is measured by following the increase of yellow color produced from thiocholine when it reacts with dithiobisnitrobenzoate ion. It is based on coupling of these reactions: The latter reaction is rapid and the assay is sensitive (i.e. a 10 μ1 sample of blood is adequate). The use of a recorder has been most helpful, but is not essential. The method has been used to study the enzyme in human erythrocytes and homogenates of rat brain, kidney, lungs, liver and muscle tissue. Kinetic constants determined by this system for erythrocyte eholinesterase are presented. The data obtained with acetylthiocholine as substrate are similar to those with acetylcholine.
A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.
Histochemical demonstration of cholinesterase (ChE) activity and inhibition in Musca domestica L. (Diptera: Museidae) central nervous system was observed using thiocholine substrates incubated with cryostat frozen sections. Topical application of organophosphorus (OP) and carbamate insecticides showed that the brain of the fly was a secondary site of action for the toxicants, while the peripheral regions of the thoracic ganglion were the primary areas of ChE inhibition. Inhibition with the OP compounds seemed to penetrate into the neuropile of the ganglia with time. No penetration further than the perineurium occurred with the carbamates. Reactivation of ChE was noted in dead flies with both the OP and carbamate compounds. The possible importance of the peripheral ChE of the thoracic ganglion is considered in conjunction with symptomology of poisoning.
Isolation and Identification of the major insecticidal compound of poleo (Lippia stoechadefolice)
- Grundy