Oviposition-altering and ovicidal potentials of five essential oils against female adults of the dengue vector, <Emphasis Type="BoldItalic">Aedes aegypti</Emphasis> L.

The oviposition deterrence and ovicidal potential of five different essential oils, peppermint oil (Mentha piperita), basil oil (Ocimum basilicum), rosemary oil (Rosemarinus officinalis), citronella oil (Cymbopogon nardus), and celery seed oil (Apium graveolens), were assessed against female adults of the dengue vector, Aedes aegypti L. Multiple concentration tests were carried out where cups containing 1 mL of different concentrations (100%, 10%, 1%, 0.1%) of the oils and 199 mL of water were used for oviposition. The number of eggs laid and the larvae hatched in each cup were scored to evaluate the oviposition deterrent and ovicidal potentials of the oils. Our investigations revealed that the addition of 100% oil (pure oil) caused complete oviposition deterrence except in A. graveolens which resulted in 75% effective repellency. The use of 10% oil resulted in the maximum deterrence of 97.5% as shown by the M. piperita oil while other oils caused 36–97% oviposition deterrence as against the control. The oviposition medium with 1% oil showed decreased deterrent potential with 30–64% effective repellency, the M. piperita oil being exceptional. However, as the concentrations of the oil were reduced further to 0.1%, the least effective oil observed was A. graveolens (25% ER). Also, the M. piperita oil showed much reduced activity (40%) as compared to the control, while the other oils exhibited 51–58% repellency to oviposition. The studies on the ovicidal effects of these oils revealed that the eggs laid in the water with 100% essential oils did not hatch at all, whereas when 10% oils were used, only the R. officinalis oil resulted in 28% egg hatch. At lower concentrations (1%), the oils of M. piperita, O. basilicum, and C. nardus showed complete egg mortality while those of A. graveolens and R. officinalis resulted in 71% and 34% egg hatches, respectively. When used at 0.1%, the O. basilicum oil was found to be the only effective oil with 100% egg mortality, whereas other oils resulted in 16–76% egg mortality, the least mortality caused by the A. graveolens oil. These results suggest that these essential oils can be employed in a resistance-management program against A. aegypti. Further detailed research is needed to identify the active ingredient in the extracts and implement the effective mosquito management program.     

Housefly (Musca domestica L.) control potential of Cymbopogon citratus Stapf. (Poales: Poaceae) essential oil and monoterpenes (citral and 1,8-cineole)

In spite of being a major vector for several domestic, medical, and veterinary pests, the control aspect of the common housefly, Musca domestica L. (Diptera: Muscidae) is often neglected. In the present study, the essential oil of Cymbopogon citratus and its major components were evaluated for control of housefly. The chemical composition analysis of C. citratus oil by gas chromatographic mass spectrometry (GC–MS) revealed citral (47 %) and 1,8-cineole (7.5 %) as principal components. The analysis of oil vapor by solid phase microextraction (SPME/GC–MS) showed increase in citral (74.9 %) and 1,8-cineole (8.6 %) content. Assay of oil against housefly larvae and pupae through contact toxicity assay showed lethal concentration (LC)₅₀ value of 0.41 μl/cm² and of percentage inhibition rate (PIR) of 77.3 %, respectively. Fumigation assay was comparatively more effective with LC₅₀ of 48.6 μl/L against housefly larvae, and a PIR value of 100 % against housefly pupae. The monoterpenes, citral, and 1,8-cineole, when assessed for their insecticidal activity against housefly larvae, showed LC₅₀ of 0.002 and 0.01 μl/cm² (contact toxicity assay) and LC₅₀ of 3.3 and 2.4 μl/L (fumigation assay). For pupicidal assay, both citral and 1,8-cineole had a PIR value of 100 %. High efficacy of citral and 1,8-cineole against housefly, established them to be an active insecticidal agent of C. citratus oil. The study demonstrates potentiality of C. citratus oil as an excellent insecticide for housefly control, and the results open up the opportunity of oil/monoterpenes being developed into an eco-friendly, economical, and acceptable product.     

Chemical composition,antioxidant activity and antifungal effects of five Iranian essential oils against Candida strains isolated from urine samples

Systemic candidiasis has become an emerging fungal infection in recent years. Anti-Candida resistance to conventional antifungal agents has subsequently increased. This study reported the chemical composition, antioxidant and anti-Candida activity of Origanum majorana, Artemisia dracunculus, Cymbopogon citrate, Cinnamomum verum and Caryophyllus aromaticus essential oils. Different Candida species, from urine tracts of hospitalized patients, were included to be challenged with understudied essential oils. Chemical compositions were determined using gas chromatography/mass spectroscopy (GC/MS) analysis and antioxidant activity was measured using DDPH assay. MIC of these essential oils was evaluated using broth micro-dilution test. Caryophyllus aromaticus had the highest antioxidant activity while the lowest antioxidant activity was for Artemisia dracunculus. MICs of Cinnamomum verum, Caryophillium aromaticus, Artemisia dracunculus, Origanum vulgare and Cymbopogon citratus essential oils ranged from 125 to 175 μg/mL (mean value: 147.7 ± 25.5 μg/mL), 700 to 1000 μg/mL (mean value: 740.9 ± 105.4 μg/mL), 1000 to 2000 μg/mL (mean value: 1454.5 ± 509.6 μg/mL), 173 to 350 μg/mL (mean value: 208 ± 55.8 μg/mL) and 125 to 175 μg/mL (mean value: 156.8 ± 24.6 μg/mL) for different Candida species, respectively. In general, natural compounds are suitable to be used as anti-Candida and antioxidant agents. However in this stage, these compounds could be applied as supplementary agents along with conventional antifungal drugs.     

Effect of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L.

The present study aimed to evaluate the essential oil and an isolated compound from the leaves of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L. The plant material was macerated and steam distilled using clavenger apparatus for oil extraction. The essential oil was tested at different concentrations of 100, 50, 25, 12.5 and 6.25 ppm concentrations against the larvae of Ae. albopictus. The isolated compound was tested for larvicidal, ovicidal, repellent, oviposition deterrent and adulticidal activities at 10, 5, 2.5, 1.25 and 0.625 ppm concentrations. The essential oil exhibited LC₅₀ values of 194.63 and 199.65 and confertifolin exhibited LC₅₀ values of 2.02 and 3.16 against the second and fourth instar larvae of Ae. albopictus, respectively. The ovicidal activity of 100 % on 0- to 6-h-old eggs, repellent activity of 320.6 min, oviposition deterrent activity of 98.51 % and adulticidal activity of 100 % at 10 ppm concentration of confertifolin were recorded. No mortality of was observed in negative control. To the best of our knowledge, this is the first report on the potential mosquitocidal activities of confertifolin against Ae. albopictus.     

Repellency of essential oils extracted from Thai native plants against Aedes aegypti (Linn.) and Culex quinquefasciatus (Say)

Repellent activity of essential oils derived from 10 Thai native plants, belonging to three families were evaluated against female Aedes aegypti and Culex quinquefasciatus and to compare them with a commercial chemical repellents (DEET; N,N-diethyl-3-methylbenzamide 20 % w/w; Sketolene Shield®). Each test repellent was applied at 1, 5, and 10 % concentrations for testing by arm in cage method. The results showed significant differences in repellency among the repellents by mosquito species. The protection time of the essential oils against Ae. aegypti ranged from 3 to 30 min. According to the Culex mosquito, it showed the protection time ranged from 3 to 260 min. 10 % Boesenbergia rotunda essential oil provided the best efficiency, in which protection time was 4.3 h as equal as DEET. The essential oils which exhibited protection time more than 2 h were those of 10 % Zingiber zerumbet, Litsea petiolata, Curcuma zedoaria, and Zingiber cassumunar essential oils (3.1, 2.8, 2.6, and 2.3 h, respectively). The biting percentage ranged from 0.9 to 18.0 % and 0.8 to 3.6 % against Ae. aegypti and Cx. quinquefasciatus, respectively. The results revealed that the potential of essential oil extracted from B. rotunda, Z. zerumbet, L. petiolata, C. zedoaria, and Z. cassumunar had attributes of good repellent and deterred biting. We recommend the five essential oils for further study to develop as commercial repellents.     

Therapeutic efficacy of Broadline® against notoedric mange in cats

The efficacy of a novel topical combination of fipronil 8.3 % w/v, (S)-methoprene 10 % w/v, eprinomectin 0.4 % w/v, and praziquantel 8.3 % w/v (Broadline®, Merial) was evaluated in 18 cats naturally infested by Notoedres cati in a controlled, blinded clinical efficacy study. Cats were blocked on pretreatment bodyweight and randomly allocated to two groups of nine cats each. One group served as control (untreated) and one group was treated once topically with Broadline® according to the label instructions. Skin scrapings (three scrapings per animal per occasion) were collected prior to treatment and every other week for 8 weeks thereafter and examined for live N. cati mites. In addition, lesions were evaluated at each sampling to monitor the clinical recovery. Based on live mite counts, efficacy against N. cati of a single topical administration with Broadline® was >99 %, and all treated cats recovered from clinical signs of notoedric mange. No treatment-related adverse events were observed.     

Bioactivity of Dianthus caryophyllus, Lepidium sativum, Pimpinella anisum, and Illicium verum essential oils and their major components against the West Nile vector Culex pipiens

Mosquitoes constitute a severe health problem in many areas all over the world. There are many regions of the tropics and subtropics where mosquitoes are one of the main reasons for inhibiting the economic upgrade. Except nuisance, their medical importance is another matter of attention since mosquitoes are vectors for a wide variety of vector-borne diseases. Due to disadvantages of currently used chemical control methods, it is unavoidable to search for eco-friendly new molecules. We report herein the evaluation of the larvicidal effect exhibited by essential oils of Dianthus caryophyllus, Lepidium sativum, Pimpinella anisum, and Illicium verum against late third to early fourth instar mosquito larvae of Culex pipiens. Furthermore, phytochemical analysis of plant samples revealed their major compounds to be β-caryophyllene, eugenol, eucalyptol, α-terpinyl acetate, and (E)-anethole which were also tested for their potential larvicidal activity. For D. caryophyllus and L. sativum, this was the first report on the chemical composition of their essential oils. The essential oils of I. verum and P. anisum demonstrated high larvicidal activity with a LC₅₀ <18 mgL^?1. The other two essential oils of D. caryophyllus and L. sativum revealed moderate larvicidal activity, displaying a LC₅₀ value above 50 mgL^?1. Among the pure components, the most toxic were eugenol, (E)-anethole, and α-terpinyl acetate, with LC₅₀ values 18.28, 16.56, and 23.03 mgL^?1, respectively. Eucalyptol (1,8 cineole) and β-caryophyllene were inactive at concentrations even as high as 100 mgL^?1, showing the least significant activity against mosquito larvae. Results allow some rationalization on the relative importance of the major compounds regarding the larvicidal activity of selected essential oils and their potential use as vector control agents.     

Further insecticidal activities of essential oils from Lippia sidoides and Croton species against Aedes aegypti L.

This study assessed new insecticidal activities of essential oils from Lippia sidoides and Croton species (Croton zehntneri, Croton nepetaefolius, Croton argyrophylloides, and Croton sonderianus) against Aedes aegypti mosquito. In addition, the acute toxicity upon mice was determined. All essential oils showed inhibition of egg hatching, with IC₅₀ values ranging from 66.4 to 143.2 μg?mL^?1, larvicidal activity with LC₅₀ ranging from 25.5 to 94.6 μg?mL^?1, and pupicidal action with PC₅₀ ranging from 276.8 to over 500 μg?mL^?1. Only L. sidoides, C. zehntneri, and C. argyrophylloides essential oils were able to inhibit the oviposition of female gravid mosquitoes with OD₅₀ values of 35.3, 45.3, and 45.8 μg?mL^?1, respectively. Oral acute toxicity in mice showed that C. sonderianus and C. argyrophylloides oils are nontoxic (LD₅₀?>?6,000 mg.kg^?1) while C. nepetaefolius, C. zehntneri, and L. sidoides oils are moderately toxic (LD₅₀ 3,840; 3,464, and 2,624 mg.kg^?1, respectively). The results indicate that these oils are promising sources of bioactive compounds, showing low or no toxicity to mammals.     

Efficacy of botanical extracts against Japanese encephalitis vector, Culex tritaeniorhynchus

The purpose of the present study was to assess the effect of leaf hexane and chloroform extracts of Aegle marmelos, Andrographis lineata, Andrographis paniculata, Cocculus hirsutus, Eclipta prostrata, and Tagetes erecta on repellent, ovicidal, and oviposition-deterrent activities against Culex tritaeniorhynchus Giles (Diptera: Culicidae). The repellent action of the plant extracts tested varied depending on the plant species, part, solvent used in extraction, and the extract dose. The hexane extract of A. paniculata was more effective in exhibiting the repellent action against the mosquito as compared with A. lineata extract. Complete protections for 150 min were found in hexane extract of A. paniculata at 500 ppm against mosquito bites. Mean percent hatchability of the ovicidal activity was observed 24 h after treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. No hatchability was observed with hexane, and chloroform extracts of A. lineata, A. paniculata, and hexane extract of T. erecta were exerted at 1,000 ppm. The percentage of effective oviposition repellency were 95.90, 94.75, 95.04, 90.58, 87.93, 87.14, 94.82, 95.71, 92.26, 90.58, 83.35, and 78.16 at 500 ppm, and the lowest repellency was 69.93, 53.06, 64.81, 70.06, 51.82, 54.54, 48.31, 66.71, 68.82, 61.85, 34.84, and 39.53 at 31.25 ppm in hexane and chloroform extracts of A. marmelos, A. lineata, A. paniculata, C. hirsutus, E. prostrata, and T. erecta, respectively. The oviposition activity index values revealed that the solvent plant extracts have deterrent effect, and they caused a remarkable negative response resulting in oviposition of very few eggs. These results clearly reveal that the hexane extracts of A. marmelos and A. paniculata served as a potential repellent, ovicidal, and oviposition deterrent against Japanese encephalitis vector, C. tritaeniorhynchus.     

Larvicidal, oviposition, and ovicidal effects of Artemisia annua (Asterales: Asteraceae) against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus (Diptera: Culicidae)

This study focuses on the larvicidal, oviposition, and ovicidal effects of a crude extract of Artemisia annua against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus. Dried cells of Artemisia annua from cell suspension cultures were extracted using hexane. The extract showed moderate larvicidal effects against mosquitoes. At 24-h post treatment, the LC₅₀ values for Anopheles sinensis, Aedes aegypti, and Culex quinquefasciatus were recorded as 244.55, 276.14, and 374.99 ppm, respectively. The percentage mortality of larvae was directly proportional to the tested concentration. Anopheles sinensis was found to be the most susceptible species, whereas Culex quinquefasciatus was the most tolerant to the Artemisia annua extract. The results indicated that the Artemisia annua extract showed concentration-dependent oviposition deterrent activity and had a strong deterrent effect. At 500 ppm, the percentage effective repellency was more than 85 % compared with the control group for all the species, with oviposition activity index values of ?0.94, ?0.95, and ?0.78 for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. In the ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of Artemisia annua extract was significantly lower than the control, with values of 48.84?±?4.08, 38.42?±?3.67, and 79.35?±?2.09 % for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. Artemisia annua was found to be more effective against Aedes aegypti and Anopheles sinensis compared with Culex quinquefasciatus. This study indicated that crude extract of A. annua could be a potential alternative for use in vector management programs.     

Efficacy of herbal shampoo base on native plant against head lice (Pediculus humanus capitis De Geer,Pediculidae: Phthiraptera) in vitro and in vivo in Thailand

Head lice infestation (or pediculosis) is an important public health problem in Thailand, especially in children between the ages 5 and 11 years. Head lice resistance is increasing, chemical pediculicides have lost their efficacy, and, therefore, alternative pediculicides such as herbal shampoos have been proposed to treat head lice infestation. Thus, the present study investigated the efficacy of three herbal shampoos based on native plants in Thailand (Acorus calamus Linn., Phyllanthus emblica Linn., and Zanthoxylum limonella Alston) against head lice and compared them with carbaryl shampoo (Hafif shampoo®, 0.6 %?w/v carbaryl), malathion shampoo (A-Lice shampoo®, 1.0 %?w/v malathion), and commercial shampoos (Babi Mild Natural’ N Mild® and Johnson’s baby shampoo®) in order to assess their in vitro and in vivo efficacy. For in vitro study, doses of 0.12 and 0.25 ml/cm² of each herbal shampoo were applied to filter paper, then 10 head lice were place on the filter paper. The mortalities of head lice were recorded at 5, 15, 30, and 60 min. The results revealed that all herbal shampoo were more effective on pediculicidal activity than chemical and commercial shampoos with 100 % mortality at 15 min; LT₅₀ values ranged from 0.25 to 1.90 min. Meanwhile, chemical shampoos caused 20–80 % mortality, and LT₅₀ values ranged from 6.50 to 85.43 min. On the other side, commercial shampoos showed 4.0 % mortality. The most effective pediculicide was Z. limonella shampoo, followed by A. calamus shampoo, P. emblica shampoo, carbaryl shampoo, malathion shampoo, and commercial shampoo, respectively. In vivo results showed that all herbal shampoos were also more effective for head lice treatment than chemical and commercial shampoos with 94.67–97.68 % of cure rate after the first treatment; the second treatment, 7 days later, revealed that the cure rate was 100 %. Meanwhile, chemical shampoo showed 71.67–93.0 % of cure rate and, unfortunately, commercial shampoos were nontoxic to head lice and showed 0 % of cure rate after the first and the second treatments. Our data showed that three herbal shampoos of native plants in Thailand in this study are suitable to be used as pediculicides for Thai children since it is safe for children and there is no side-effect after application.     

Oviposition deterrent activity of three mosquito repellents diethyl phenyl acetamide (DEPA), diethyl m toluamide (DEET), and diethyl benzamide (DEB) on Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus

Oviposition deterrent activity of three mosquito repellents namely diethyl phenyl acetamide (DEPA), diethyl benzamide (DEB) along with diethyl toluamide (DEET) was studied in the laboratory against Aedes aegypti, A. albopictus, and Culex quinquefasciatus mosquitoes. All the repellents evaluated at three log concentrations 0.1, 0.01, and 0.001 % in comparison with control by dual choice method. The oviposition response and oviposition activity index (OAI) was estimated by counting number of eggs laid in both the treatment and control. Mean OAI determined for A. aegypti was in the range of ?0.23 to +0.22, ?0.3 to +0.27, and +0.04 to +0.33 for DEPA, DEET, and DEB, respectively, whereas it was ?0.77 to ?0.035, ?0.92 to +0.001, and ?0.77 to ?0.07 for A. albopictus and ?0.927 to ?0.251, ?1 to ?0.41, and ?0.94 to ?0.17 for C. quinquefasciatus. The oviposition deterrent activity was observed in the order of DEET > DEPA > DEB. Similarly, the response of species toward the repellents as oviposition deterrent was in the trend of C. quinquefasciatus > A. albopictus > A. aegypti. The finding suggests potential role of mosquito repellents as oviposition deterrent.     

Acaricidal activity of petroleum ether extracts from Eupatorium adenophorum against the ectoparasitic cattle mite,Chorioptes texanus

In this study, we evaluated the acaricidal efficacy of extracts obtained from the plant Eupatorium adenophorum against the common cattle mite Chorioptes texanus. The results showed that 95 % ethanol extracts at concentrations of 1.0, 0.5, and 0.25 g/mL (w/v) were highly toxic to C. texanus in vitro, killing 100 % of mites in 4 h. Similarly, petroleum ether extracts of E. adenophorum resulted in between 80 and 100 % mortality of mites in vitro at concentrations of 0.1, 0.05, and 0.025 mL/mL (v/v) within 4 h. In clinical trials, all infected individuals completely recovered after two treatments administered at 7-day intervals and remained disease-free at 60 days posttreatment. The clinical effect of treatment with E. adenophorum petroleum ether extracts was similar to that of treatment with the acaricide fenvalerate. These results indicated that E. adenophorum contains novel potential acaricidal compounds that can effectively control mites in livestock.     

Bioefficacy of essential oils of medicinal plants against housefly, Musca domestica L

The housefly Musca domestica L. is recognized as a public health pest causing a serious threat to human and livestock by vectoring many infectious diseases. Chemical control method commonly used against this pest, though effective, has some major disadvantages, such as development of insect resistance and bioaccumulation. Pest management strategies for populations of houseflies are needed. Presently, bioinsecticides, especially those derived from plant origin, have been increasingly evaluated in controlling insects of medical importance. In order to search for effective and ecofriendly control agents, the essential oils of Mentha piperita, Zingiber officinalis, Emblica officinalis, and Cinnamomum verum were evaluated for their larvicidal, attractant/repellent, and oviposition attractant/deterrent activity against M. domestica. The highest larvicidal activity, i.e., C(50)?=?104?ppm was shown by M. piperita. This oil also exhibited 96.8?% repellency at the concentration of 1?%. The highest oviposition deterrence activity of 98.1?% was also exhibited by M. piperita oil at the concentration of 1?%. Among the remaining plants, the essential oil of Z. officinalis exhibited significant bioactivities against M. domestica with larvicidal activity, i.e., lethal concentration (LC)(50)?=?137?ppm, repellency of 84.9 and 98.1?% oviposition deterrence both at 1?% concentration. The other two plant oils, viz., C. verum and E. officinalis, showed relatively moderate bioefficacy with larvicidal activity, i.e., LC(50)?=?159 and 259?ppm, repellency of 77.9 and 63.0?% while oviposition deterrence of 60.0 and 42.6?%, respectively. The result revealed that the essential oils of M. piperita have control potential against M. domestica and should be further explored as a component of integrated vector management program.     

Bilateral deficit and EMG activity during explosive lower limb contractions against different overloads

We investigated whether bilateral deficit (BLD): (1) is observed during explosive lower limb contractions; (2) can be attributed to a reduction of neural drive and/or (3) to a different muscle coordination, and/or (4) to changes of the muscle force–velocity (F–v) relationship. Ten volunteers performed maximal explosive efforts of ~450 ms on a sledge ergometer, with both lower limbs (BL), with the right and left limb separately (ML), against different overloads. Peak-force (F, N), peak-power (w, W), sledge peak-velocity (v, m/s) and electromyography (EMG) of vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF) and gastrocnemius medialis (GM) were recorded. Average values over the six overloads of F and w, developed by right or left limb during BL, were significantly lower (883 ± 200 and 918 ± 141 N; 1089 ± 407 and 1099 ± 325 W) than those developed during ML contractions (1285 ± 177 and 1306 ± 147 N; 1536 ± 408 and 1497 ± 392 W). VL and RF iEMGs were lower in BL than in ML (74 ± 28 vs. 91 ± 21% MVC and 39 ± 21 vs. 56 ± 28% MVC). The coordination among the four muscles, as determined from an analysis of the time course of iEMG, expressed as percentage of that attained at the end of the push, was poorer in BL, as compared to ML. BL F–v curves were different as compared to the ML ones, the force and power developed, at a given v, being significantly larger in ML. It is concluded that BLD occurs also during explosive pushes with the lower limbs, and that it is mainly due to different muscle coordination.     

Bioactivities of some essential oils against the camel nasal botfly,Cephalopina titillator

Nasopharyngeal myiasis of camels is caused by the larvae of Cephalopina titillator. We determined the efficacy of essential oils (EOs) of pumpkin, Cucurbita maxima; lupinus, Lupinus luteus; garlic oil, Allium sativum; and peppermint, Mentha piperita, against the third larval stage of C. titillator using larval immersion tests. The positive control group was treated with ivermectin and the negative control one was treated with distilled water and few drops of Tween 80. Larvae were reared until adult emergence. The data indicated that complete larval mortalities were reached 24 h post treatment (PT) with 2 % pumpkin, 7.5 % garlic and peppermint, 30 % lupinus, and 0.15 % ivermectin. The lethal values, LC50s, were 0.20, 0.44, 0.42, 0.47, and 0.03 %, respectively. Pumpkin and ivermectin were 2 and 17 times, respectively, more effective than the other EOs. Ivermectin was seven times more intoxicating than pumpkin oil. Formation of pupae had been stopped after treatment of larvae with 2 % pumpkin, 7.5 % garlic and peppermint, 30 % lupines, and 0.04 % ivermectin. Adult emergence had been completely ceased following treatment of larvae with 0.5 % EOs and 0.04 % ivermectin. Morphological abnormalities were pronounced after treatments, and peppermint oil was the foremost cause of deformation in larvae (44 % PT with 7.5 %) and pupae (40 % PT with 2 %). Pumpkin oil (6 %) was selected to be the drug of choice for controlling C. titillator. Besides their insecticidal effects, EOs are much safer than ivermectin regarding health and environmental issues. Consequently, EOs described herein merit further study as potential nasal drench for C. titillator control.     

Scolicidal effectiveness of essential oil from Zataria multiflora and Ferula assafoetida: disparity between phenolic monoterpenes and disulphide compounds

Hydatidosis in humans and animals is a substantial cause of deaths in many parts of the world. Surgery and the chemotherapeutic agents are the main treatments for hydatid disease; however, most of them are accompanied by adverse side effects. In this study, the scolicidal effect of essential oils from Zataria multiflora and Ferula assafoetida against Echinococcus granulosus protoscolices was investigated. Essential oils from Z. multiflora and F. assafoetida were prepared by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Carvacrol (29.2 %), thymol (25.4 %), p-cymene (11.2 %), linalool (9.6 %), and γ-terpinene (8 %) were detected as the main components of the Z. multiflora, while the main components of F. assafoetida were E-1-propenyl-sec-butyl disulfide (62.7 %), β-ocimene (21.7 %) and β-pinene (5 %). Scolicidal activities of the essential oils against protoscolices for Z. multiflora and F. assafoetida were obtained at concentrations more than 17 and 60 μg/mL, respectively. Accordingly, it was concluded that both essential oils can selectively reduce protoscolices viability, and Z. multiflora, which contains phenolic monoterpenes, is more cytotoxic rather than F. assafoetida which contains disulfide compounds. Therefore, Z. multiflora and F. assafoetida could be recommended as a treatment against hydatid cyst.     

Essential oil composition, adult repellency and larvicidal activity of eight Cupressaceae species from Greece against Aedes albopictus (Diptera: Culicidae)

The present study evaluated leaf essential oils from eight Cupresaceae species; Cupressus arizonica, Cupressus benthamii, Cupressus macrocarpa, Cupressus sempervirens, Cupressus torulosa, Chamaecyparis lawsoniana, Juniperus phoenicea, and Tetraclinis articulata for their larvicidal and repellent properties against Aedes albopictus, a mosquito of great ecological and medical importance. Based on the LC₅₀ values, C. benthamii essential oil was the most active (LC₅₀?=?37.5 mg/L) while the other tested Cupressaceae essential oils provided rather moderate toxicity against larvae (LC₅₀?=?47.9 to 70.6 mg/L). Under the used laboratory conditions, three of the essential oils (C. benthamii, C. lawsoniana, and C. macrocarpa) provided sufficient protection against mosquito adults, equivalent to the standard repellent “Deet” in the 0.2 mg/cm² dose, while C. macrocarpa assigned as the superior repellent oil in the 0.08 mg/cm² dose. Chemical analysis of the essential oils using gas chromatography and gas chromatography–mass spectrometry revealed the presence of 125 components.     

Effects of essential oils from Cymbopogon citratus (DC) Stapf., Lippia sidoides Cham., and Ocimum gratissimum L. on growth and ultrastructure of Leishmania chagasi promastigotes

The current therapy for leishmaniasis, which affects annually about 2 million people, is far from satisfactory. All available drugs require parenteral administration and are potentially toxic. Plant essential oils have been traditionally used in folk medicine and appear as valuable alternative source for chemotherapeutic compounds. In this study, we demonstrated the effect of essential oils from Cymbopogon citratus, Lippia sidoides, and Ocimum gratissimum on growth and ultrastructure of Leishmania chagasi promastigote forms. Steam distillation was used to isolate the essential oils, and their constituents were characterized by gas chromatography coupled to mass spectrometry and nuclear magnetic resonance. All essential oils showed in vitro inhibitory action on L. chagasi promastigotes growth in a dose-dependent way, with IC₅₀/72 h of 45, 89, and 75 μg/mL for C. citratus, L. sidoides, and O. gratissimum, respectively. Drastic morphological alterations were observed in all essential oil-treated parasites, including cell swelling, accumulation of lipid droplets in the cytoplasm, and increase of acidocalcisome volume. Furthermore, aberrant-shaped cells with multi-septate body were observed by scanning electron microscopy, suggesting an additional effect on cytokinesis. Taken together, our data show that these essential oils affect the parasite viability being the C. citratus essential oil the most effective against L. chagasi.     

Acaricidal activity of essential oils from five endemic conifers of New Caledonia on the cattle tick Rhipicephalus (Boophilus) microplus

The aim of the present study was to demonstrate acaricidal activity on the cattle tick Rhipicephalus (Boophilus) microplus of essential oils from endemic conifers of New Caledonia in the context of the development of natural alternatives. Acaricidal activity of essential oils extracted from resin and heartwood of five endemic conifers of New Caledonia (Araucaria columnaris, Agathis moorei, Agathis ovata, Callitris sulcata, and Neocallitropsis pancheri) was evaluated on 14- to 21-day-old Rhipicephalus microplus tick larvae using the Larval Packal Test bioassay. A first screening with 5 % dilute solution was carried out and the oils with 100 % of mortality at this rate were diluted until no activity was shown. The heartwood oils of the two Cupressaceae were the most active with LC₅₀ value of 0.65 % for C. sulcata and 0.55 % for N. pancheri while resin oil of A. columnaris (LC₅₀?=?1.62 %) was the most active of the Araucariaceae family. Negative control (ethanol) was not toxic to the larvae. The chemical composition of essential oil from resin of A. columnaris was analyzed by gas chromatography–mass spectrometry. The essential oil was characterized by high level of sesquiterpene hydrocarbons and oxygenated sesquiterpenes and was composed mainly of aromadendrene (23.1 %) and bicyclogermacrene (16.0 %). In order to compare different plant resources in a sustainable program of natural acaricide, an “essential oil efficiency EOE” can be measured as the ratio between the yield of extraction and LC₅₀ value. This study shows that A. columnaris (EOE?=?2.36) and N. pancheri (EOE?=?3.51) could provide valuable and effective natural acaricides for control of the cattle tick R. microplus.