The active compounds and AChE inhibitor of the methanol extract of Adonis coerulea maxim against Psoroptes cuniculi.

Adonis coerulea Maxim. presents acaricidal activity in vitro and in vivo, and inhibits AChE and other enzymes activities. However, the active compounds against Psoroptes cuniculi were still unclear. AChE, a common acaricidal and insecticidal target, plays a key role in neural conduction of mites. In this study, using surface plasmon resonance (SPR) technology, AChE was used as a target to capture the compounds from A. coerulea methanol extract (MEAC). After calculating the affinity with molecular docking, the inhibitory effect of compounds against AChE was studied. Results showed that 27 compounds were captured by AChE and identified from MEAC by LC-MS/MS. Among of these compounds, eight compounds presented the high affinity with AChE and high scores in molecular docking assay, especially for silibinin (-12.19 kcal/mol) and vitexin (-11.72 kcal/mol). Further studies showed that although these compounds have the weak cytotoxicity against C6/36 cells, silibinin, quercetin and corilagin could inhibit AChE activity with IC50 values of 40.11 µg/mL, 46.15 µg/mL and 50.98 µg/mL, respectively. These results indicated that silibinin, quercetin and corilagin may be responsible for AChE inhibition which contributes to the acaricidal properties of A coerulea. This study lays the foundation for developing sensitive and sustainability methods for active compound detection from plants.

Acaricidal activity of plant-derived essential oil components against Psoroptes ovis in vitro and in vivo.

BACKGROUND: Treatment of Psoroptes ovis in cattle is limited to topical acaricides or systemic treatment with macrocyclic lactones. Treatment failure of macrocyclic lactones has been reported. The aim of this study was to evaluate a potential alternative treatment against P. ovis. METHODS: The acaricidal activity against P. ovis of four plant-derived essential oil components, i.e. geraniol, eugenol, 1,8-cineol and carvacrol, was assessed in vitro and in vivo. In vitro contact, fumigation and residual bioassays were performed. In addition, 12 Belgium Blue cattle were artificially infested and treated topically once a week for three successive weeks with carvacrol in Tween-80 (treatment group) or with Tween-80 alone (control). The efficacy of carvacrol was determined by the reduction in lesion size and mite counts. Six additional animals were topically treated with carvacrol to assess local adverse reactions. RESULTS: Three components showed a concentration-dependent acaricidal activity in a contact assay, with LC50 of 0.56, 0.38 and 0.26% at 24 h for geraniol, eugenol, and carvacrol, respectively. However, 1,8-cineol showed no activity at any of the tested concentrations in a contact bioassay. In a fumigation bioassay, carvacrol killed all mites within 50 min after treatment, whereas geraniol, eugenol and 1,8-cineol needed 90 to 150 min. Following a 72 h incubation period in a residual bioassay, carvacrol killed all mites after 4 h of exposure to LC90, while geraniol and eugenol killed all mites only after 8 h exposure. Based on these results, carvacrol was further assessed in vivo. Mite counts in the treatment group were reduced by 98.5 ± 2.4% at 6 weeks post-treatment, while in the control group the mite population had increased. Topical application of carvacrol only caused mild and transient erythema 20 min after treatment. No other side effects were observed. CONCLUSIONS: Considering the strong acaricidal activity of carvacrol in vitro and in vivo and the mild and transient local side effects, carvacrol shows potential as an acaricidal agent in the treatment of P. ovis in cattle.

Acaricidal activity and enzyme inhibitory activity of active compounds of essential oils against Psoroptes cuniculi.

Plant essential oils and its chemical compositions are commonly applied in medicinal and other industries due to their broad advanced pharmacological activities. In the present study, we systematically evaluated the acaricidal activities of twelve compounds of essential oils against Psoroptes cuniculi in vitro and in vivo. In addition, to support the clinic uses, their toxicities against immortalized human keratinocytes (HaCaT) and human liver cells (HL-7702) and skin irritation were studied for evaluating the liver and skin safety. The possible mechanism of action of certain chemical were investigated by determining the inhibitory activities against cytochrome P450 (P450) acetylcholinesterase (AChE) and glutathione-S-transferase (GST). Among all tested compounds, eugenol exhibited the best acaricidal activity with LC50 value of 56.61 µg/ml in vitro. Meanwhile, after the treatment of eugenol for five times within 10 days, the P. cuniculi were eliminated in the naturally infested rabbits, no skin irritation was found in rabbits treated by eugenol. Moreover, eugenol presented no or weak cytotoxicity against HaCaT cells and HL-7702 cells with IC50 values of greater than 100 µg/ml. Furthermore, the moderate inhibitory activities of eugenol against mites P450 and AChE were demonstrated. Above results indicated that eugenol presented the promising acaricidal activity against P. cuniculi in vitro and in vivo, is safe for both humans and animals at the given doses. This work lays the foundation for the development of eugenol as an environmentally friendly acaricide agent.

The acaricidal activity and mechanism of eugenol on Psoroptes cuniculi.

In this study, the acaricidal effect of eugenol was measured and its mechanism of action investigated. The results showed that eugenol possessed the effect of killing Psoroptes cuniculi, and could regulate the mRNA expression of glutathione S-transferase (GST), catechinic acid (Ca) and thioredoxin (Trx). PPAR, NF-kappa B, TNF, Rap 1 and Ras signaling pathways might be the main pathways that involved into the process of killing mites. These findings suggested that eugenol could be developed into a new kind of acaricide, and further expand current knowledge on the mechanisms of eugenol for killing Psoroptes cuniculi of eugenol.

The toxicity and the acaricidal mechanism against Psoroptes cuniculi of the methanol extract of Adonis coerulea Maxim.

SCOPE: Adonis coerulea Maxim. is a perennial herbaceous plant that grows in scrub, grassy slope areas, and as traditional medicine it has been used to treat animal acariasis for thousands of years. In this paper, we aimed to study the acute toxicity and cytotoxicity of the methanol extract of A. coerulea (MEAC) in vivo and in vitro for supporting the clinic uses. The acaricidal activity and the mechanism of action against Psoroptes cuniculi were investigated. RESULTS: The results showed that isoorientin, luteolin and apigenin were the primary compounds in MEAC. The toxicity test showed that median lethal dose (LD50) and the 50% inhibitory concentration (IC50) of MEAC were estimated to be more than 5000mg/kg in mice in vivo and more than 50mg/ml against RAW 264.7 and GM00637 cells in the 3-(4, 5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) test. After culturing with MEAC, the activities of superoxide dismutase (SOD), catalase (CAT), malonyldialdehyde (MDA), glutathione-S-transferase (GST), acetylcholinesterase (AChE) and Na+-K+-ATPase of mites were evaluated. Compared with the control group, SOD activity of MEAC-treated group of mites was inhibited, and CAT activity was activated at the preliminary phase but was gradually inhibited over the period of incubation. MDA content reached a peak at 6h and then gradually decreased. However, GST activity in the mites was activated in a dose- and time-dependent manner. AChE and Na+-K+-ATPase activities related to neural conduction, vital functions and the transmembrane ion gradient of the mites were inhibited. CONCLUSION: MEAC is safe in the given doses in both the in vitro and the in vivo tests, can be applied in the clinic and it had good acaricidal activity. The extension of the incubation time in the mites led to dynamic disequilibrium between the production and clearing of superoxide anions, a disruption of the energy metabolism and the transmembrane ion gradient, and the inhibition of motor function. These factors may have resulted in mite death.

Sustained release ivermectin-loaded solid lipid dispersion for subcutaneous delivery: in vitro and in vivo evaluation.

This work aimed to develop a sustained release solid dispersion of ivermectin (IVM-SD) in a lipid matrix (hydrogenated castor oil, HCO) for subcutaneous delivery. Solvent-melting technology was employed to prepare IVM-SDs using HCO. The physicochemical properties of the IVM-SDs were evaluated by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). The release of IVM from IVM-SDs was evaluated with HPLC in vitro. Pharmacokinetics of IVM was studied in rabbits following a single subcutaneous administration of IVM-SD formulations. The efficacy of IVM-SD against the ear mange mite was evaluated in rabbits. IVM was completely dispersed in HCO in an amorphous state at a drug:carrier ratio lower than 1:3. No chemical interactions between drug and carrier were found besides hydrogen bonding for the amorphous IVM-SDs. The amorphous IVM-SDs formulations exhibited a sustained release of IVM versus physical mixtures (PMs) of IVM and HCO. The drug release decreased as the drug:carrier ratios decreased, and the release kinetics of IVM were controlled via diffusion. Cytotoxicity of IVM-SD to MDCK cells was lower than native IVM. The IVM plasma concentration of SD1:3 remained above 1 ng/mL for 49 d. Higher AUC, MRT, and Tmax values were obtained at a SD1:3 relative to the IVM group. The IVM-SD improved almost 1.1-fold bioavailability of drug compared with IVM in rabbits. IVM-SD could provide longer persistence against rabbit's ear mites than a commercial IVM injection. This study shows that these solid lipid dispersions are a promising approach for the development of subcutaneous IVM formulations.

Acaricidal activity of oregano oil and its major component, carvacrol, thymol and p-cymene against Psoroptes cuniculi in vitro and in vivo.

Oregano oil possesses marked antioxidant and antimicrobial activity and is widely applied in animal husbandry. In the present study, we aimed to investigate the acaricidal activities of oregano oil and its major component, carvacrol, thymol and p-cymene against Psoroptes cuniculi in vitro and in vivo. The results revealed that oregano oil exhibited significant acaricidal effects against P. cuniculi that were dose- and time-dependent response. In in vitro test, concentrations of 0.05% and 0.02% (v/v) killed all of the mites within 1h and 6h, respectively. Moreover, 0.1mg/ml (w/v) carvacrol, 0.2mg/ml (w/v) thymol and 1% p-cymene (v/v) also possessed marked acaricidal activities, and compared with the control group, elicited mean mortalities of 84.00%, 96.00% and 66% at 24h, respectively. The median lethal times (LT50) against P. cuniculi of the concentrations of 0.02%, 0.01% and 0.005% (v/v) of oregano oil, thymol, carvacrol and p-cymene were 2.171h, 11.396h, 26.102h, and 4.424h, 8.957h and 15.201h, respectively. Meanwhile, twenty naturaly infested rabbits were used to four homogeneity groups: negative control (without treatment), positive control (treated with ivermectin), group treated with 1% of oregano oil and other group with 5% of oregano oil. All the treatments were topically. After the treatment of 1% and 5% oregano oil, the P. cuniculi were completely eliminated in the rabbits, and at the end of the test (day 20), the rabbits of all treatment groups exhibited favorable mental and physical statuses. These results indicated that oregano oil could be widely applied as a potential acaricidal agent in the treatment of animal acariasis in the future.

Microwave-assisted extraction of three bioactive alkaloids from Peganum harmala L. and their acaricidal activity against Psoroptes cuniculi in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Peganum harmala L. is a perennial herbaceous, glabrous plant that grows in semi-arid conditions, steppe areas and sandy soils. It is used to treat fever, diarrhoea, subcutaneous tumours, arthralgia, rheumatism, cough, amnesia and parasitic diseases in folk medicines. In this paper, we aimed to develop a simpler and faster method for the extraction of three alkaloids from Peganum harmala L. than other conventional methods by optimizing the parameters of a microwave-assisted extraction (MAE) method, and to investigate the acaricidal activities of three compounds against Psoroptes cuniculi. MATERIALS AND METHODS: After optimizing the operating parameters with the single factor experiment and a Box-Behnken design combined with a response-surface methodology, a MAE method was developed for extracting the alkaloids from the seeds, and a high-performance liquid chromatography was used to quantify these compounds. An in vitro experiments were used to study the acaricidal activities. RESULTS: The optimal conditions of MAE method were as follows: liquid-to-solid ratio 31.3:1mL/g, ethanol concentration 75.5%, extraction time 10.1min, temperature 80.7°C, and microwave power 600W. Compared to the heat reflux extraction (HRE, 60min) and the ultrasonic-assisted extraction (UAE, 30min) methods, MAE method require the shortest time (10min) and obtain the highest yield of three compounds (61.9mg/g). Meanwhile, the LT50 values for the vasicine (1.25 and 2.5mg/mL), harmaline (1.25 and 2.5mg/mL), harmine (1.25 and 2.5mg/mL) and MAE extract (100mg/mL) against Psoroptes cuniculi were 12.188h, 9.791h, 11.994h, 10.095h, 11.293h, 9.273h and 17.322h, respectively. CONCLUSIONS: The MAE method developed exhibited the highest extraction yield within the shortest time and thus could be used to extract the active compounds from Peganum harmala L. on an industrial basis. As the active compounds of Peganum harmala L., vasicine, harmalin and harmine presented the marked acaricidal activities against Psoroptes cuniculi, and could be widely applied for the treatments of acariasis in animals.

Primary screen for potential sheep scab control agents.

The efficacy of potential acaricidal agents were assessed against the sheep scab mite Psoroptes ovis using a series of in vitro assays in modified test arenas designed initially to maintain P. ovis off-host. The mortality effects of 45 control agents, including essential oils, detergents, desiccants, growth regulators, lipid synthesis inhibitors, nerve action/energy metabolism disruptors and ecdysteroids were assessed against adults and nymphs. The most effective candidates were the desiccants (diatomaceous earth, nanoclay and sorex), the growth regulators (buprofezin, hexythiazox and teflubenzuron), the lipid synthesis inhibitors (spirodiclofen, spirotetramat and spiromesifen) and the nerve action and energy metabolism inhibitors (fenpyroximate, spinosad, tolfenpyrad, and chlorantraniliprole).

Clinical efficacy of 9-oxo-10, 11-dehydroageraphorone extracted from Eupatorium adenophorum against Psoroptes cuniculi in rabbits.

BACKGROUND: Animal acariasis is one of the important veterinary skin diseases. Chemical drugs have been widely used to treat and control this kind of disease. But many chemicals control could increase resistance in target species, toxicity and environmental hazards. We found that the 9-oxo-10, 11-dehydroageraphorone (euptox A) extracted from E. adenophorum has strong toxicity against P. cuniculi in vitro, but the in vivo acaricidal actions of euptox A have yet to be investigated. RESULTS: A 14-day experiment was performed using rabbits that were naturally infested with P. cuniculi on a farm. Rabbits were randomly divided into five groups; animals in groups A, B and C were treated in each ear topically with 4.0 ml of 2.0 and 1.0 g/L (w/v) euptox A, respectively. Animals in groups D and E were treated with ivermectin (by injection; positive controls) and glycerol with water only (by embrocation; negative controls), respectively. Each rabbit was treated twice with separate treatments on days 0 and 7. Rabbits were observed daily and detailed examinations were performed on days 0, 7 and 14, to inspect the presence or absence of mites and scabs/crusts. Seven days after the initial treatment, the mean clinical scores (presence of scabs/crusts) decreased from 3.48, 3.37, 3.43 and 3.45 to 0.37, 0.42, 0.78 and 0.38 in the ears of animals in groups A, B , C and D, respectively, which were similar to the observations recorded in the positive control rabbits. However, the clinical score for negative control rabbits did not increase significantly (P > 0.05) during the experiment, and this changed from 3.32 to 3.37 in the ears, and there were no significant differences in clinical efficacy between left and right ears. After two treatments (0 and 7 d), the rabbits in groups A, B, C and D had recovered completely 14 days after the last treatment and no recurrences of infection were observed. CONCLUSIONS: These results indicate that euptox A was potent compounds for the effective control of animal P. cuniculi in vivo.

Isolation and identification of acaricidal compounds in Eupatorium adenophorum petroleum ether extract and determination of their acaricidal activity against Psoroptes cuniculi.

We used multiple silica gel column chromatography and thin-layer chromatography coupled with (1)H nuclear magnetic resonance (NMR) and (13)C NMR to separate and identify the active acaricidal ingredients in Eupatorium adenophorum petroleum ether extract. The acaricidal activity of each compound was tested against Psoroptes cuniculi in vitro. Three compounds had strong acaricidal activity against P. cuniculi in vitro. The insecticidal effect of 0.5% compound 9ß-hydroxy-ageraphorone was better than the insecticidal effect of fenvalerate, and compounds 9-oxo-ageraphorone and 9-oxo-10,11-dehydro-ageraphorone exhibited higher insecticidal effects than 9ß-hydroxy-ageraphorone. Thus, the E. adenophorum petroleum ether extract contains an effective composition of acaricides that could potentially be developed as a promising plant-origin acaricide.

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.

Acaricidal activity of extracts from Adonis coerulea Maxim. against Psoroptes cuniculi in vitro and in vivo.

The acaricidal activity of Adonis coerulea extracts was investigated against Psoroptes cuniculi. The aqueous, methanol, acetic ether and petroleum ether extracts all showed marked acaricidal activity in vitro. Especially, the acetic ether extract possessed strong toxicity against mites in vitro with LT50 values 0.743 h, 2.730 h, 5.919 h and 22.536 h at concentrations of 500, 250, 125 and 62.5 mg/ml, respectively. At the same time, the acetic ether extract showed the best effectiveness topically to infested rabbits in vivo. After three times treatment, at the day 20, rabbits treated with A. coerulea extract were observed only small scabs or secretions in ear canal, but no mites. These findings suggested that as a potential insecticide, A. coerulea should be studied further to develop active components or a new acaricidal drug.

Clinical efficacy of botanical extracts from Eupatorium adenophorum against the scab mite, Psoroptes cuniculi.

This study evaluated the in vivo clinical efficacy of Crofton weed (Eupatorium adenophorum) extracts against the scab mite, Psoroptes cuniculi. A 30-day experiment was performed using New Zealand rabbits that were naturally infested with P. cuniculi on a farm. Rabbits were randomly divided into five groups (6 animals per group); animals in groups A, B and C were treated in each ear topically with 2 ml of 1.0, 0.5 and 0.25 g/ml (w/v) E. adenophorum ethanol extract, respectively. Animals in groups D and E were treated with ivermectin (by injection; positive controls) and glycerol with water only (by embrocation; negative controls), respectively. Each rabbit was treated twice with separate treatments on days 0 and 7. Rabbits were observed daily and detailed examinations were performed on days 0, 7, 14 and 30, to inspect the presence or absence of mites and scabs/crusts. Clinical infection and the degree of recovery were evaluated, and the rate of reduction in mites and clinical efficacy rate (%) were calculated. The clinical effect of treatment with E. adenophorum extracts was similar to treatment with ivermectin. Seven days after the initial treatment, the mean clinical scores (presence of scabs/crusts) decreased from 3.32, 3.08 and 3.17 to 0.37, 0.47 and 0.48 in the left ears of animals in groups A, B and C, respectively, and from 3.53, 3.73 and 3.67 to 0.40, 0.45 and 0.48 in the right ears of animals in groups A, B and C, respectively, which were similar to the observations recorded in the positive control rabbits. However, the clinical score for negative control rabbits did not decrease significantly (P>0.05) during the experiment, and this changed from 3.32 to 2.75 in the left ears and from 3.50 to 3.25 in the right ears, and there were no significant differences in clinical efficacy between left and right ears. After two treatments (7 days space), the rabbits in groups A, B, C and D had recovered completely 30 days after the last treatment and no recurrences of infection were observed. These results indicate that E. adenophorum contains potent compounds for the effective control of animal acariasis.

Efficacy of trans-cinnamaldehyde against Psoroptes cuniculi in vitro.

The acaricidal activity of trans-cinnamaldehyde was evaluated in vitro on Psoroptes cuniculi. In this study, different concentrations of trans-cinnamaldehyde were tested, and the observed mites mortality was compared with that observed in untreated and treated (Acacerulen R®) controls. The morphological changes in P. cuniculi treated with trans-cinnamaldehyde were examined with light microscopy. By the analysis of variance one-way test, up to 8 µg/ml of trans-cinnamaldehyde gave highly significant (P < 0.01) percentages of mite mortality compared with the untreated controls, but only up to 256 µg/ml, it showed the same efficacy of Acacerulen R®. At the same time, a bioassay was conducted by exposing mites to varying doses of trans-cinnamaldehyde in vitro cultures. The resulting data were analyzed by using a time-dose-mortality modeling technique, yielding the parameters for time and dose effects of P. cuniculi. The ß value was 2.01, indicating that trans-cinnamaldehyde had a good activity to kill P. cuniculi adults. Based on the time-dose-mortality relationships fitted and the virulence indices estimated, trans-cinnamaldehyde is a promising microbial agent for mites control.

Acaricidal activity of extract from Eupatorium adenophorum against the Psoroptes cuniculi and Sarcoptes scabiei in vitro.

The possible acaricidal activity of Eupatorium adenophorum was analyzed using extracts created by water decocting, ethanol thermal circumfluence, and steam distillation. The toxic effect of each extract was tested against Psoroptes cuniculi and Sarcoptes scabiei in vitro. Ethanol thermal circumfluence extract had strong toxicity against mites, killing all S. scabiei at 0.5 and 1.0 g/ml (w/v) concentration, while 1g/ml extract was also found to kill all P. cuniculi within a 4-h period. Similarly, 0.25, 0.5 and 1.0 g/ml concentration of extract had strong toxicity against S. scabiei, with median lethal time (LT(50)) values at 0.866, 0.785 and 0.517 h, respectively. 0.5 g/ml and 1g/ml showed strong acaricidal action against P. cuniculi; the LT(50) values were 0.93 h and 1.29 h, respectively. The median lethal concentration (LC(50)) values were 0.22 g/ml for Scabies mite and 0.64 g/ml for P. cuniculi in 1h. The results indicated that E. adenophorum contains potent acaricidal ingredients; as a first step in the potential development of novel drugs, it may provide new acaricidal compounds for the effective control of animal acariasis.

Psoroptes cuniculi induced oxidative imbalance in rabbits and its alleviation by using vitamins A, D3, E, and H as adjunctive remedial.

The oxidant/antioxidant balance of rabbits naturally infected with Psoroptes cuniculi and treated with ivermectin +/- vitamins A, D(3), E, and H supplementation was investigated. Two groups of seven mixed ♂ and ♀, 6-to-8 month-old New Zealand White rabbits, diagnosed Psoroptes mites-positive by skin scraping examination and seven clinically healthy control rabbits were examined. Blood samples were obtained on day 0 and at 28 days post-therapy to determine oxidative stress indices. On day 0, the levels of lipid peroxides were significantly higher (P ≤ 0.01) in the Psoroptes-infected rabbits compared with the healthy controls while those of reduced glutathione and the activities of the antioxidant enzymes glutathione peroxidase, glutathione-S-transferase, catalase, and superoxide dismutase were significantly lower (P ≤ 0.01). Vitamin supplementation of the ivermectin-treated rabbits revealed both faster clinical (14 days) and parasitological (10 days) recovery. It was concluded that significant alteration of oxidant/antioxidant balance is a factor in the pathogenesis of P. cuniculi infestation of rabbits, and recovery can be enhanced by combining ivermectin treatment with vitamin A, D(3,) E, and H supplementation.

Efficacy of an essential oil of Eugenia caryophyllata against Psoroptes cuniculi.

The acaricidal activity of Eugenia caryophyllata essential oil was evaluated in vitro and in vivo on Psoroptes cuniculi, a mange mite. In vitro, different concentrations of the oil were tested and the observed mites mortality was compared with that observed in untreated and treated (Acacerulen R) controls. In vivo, six P. cuniculi infected rabbits were topically treated with the oil diluted at 2.5% and compared with untreated and treated control groups of six rabbits each. In vitro, up to the concentration of 0.10% the oil gave highly significant (P<0.01) percentages of mite mortality respect to the untreated controls, but only up to 0.16% it showed the same efficacy of Acacerulen R. In vivo, the treatment with the essential oil cured all infested rabbits and no statistical differences were observed respect to the treated control group. The untreated rabbits remained infested.

Efficacy of an essential oil of Cinnamomum zeylanicum against Psoroptes cuniculi.

The aim of the present study was to investigate the in vitro and in vivo acaricidal effects of an essential oil of Cinnamomum zeylanicun leaves on Psoroptes cuniculi, a mange mite. In vitro, 2.5 ml of the essential oil diluted at different concentrations, from 10% to 0.03%, in paraffin oil were added to Petri dishes containing all motile stages of P. cuniculi. Mites mortality observed in these dishes was compared with that observed in untreated and treated (AcaCerulen R) control plates. In vivo, one group of six P. cuniculi infected rabbits was topically treated two times at seven days interval with two ml of the essential oil at the concentration of 2.5% in paraffin oil and compared with untreated and treated (AcaCerulen R) control groups of six rabbits each. After 24 h of contact, all concentrations of essential oil between 0.10 and 10% showed a good in vitro acaricidal efficacy if compared with the untreated controls (p<0.01), but only the concentrations between 0.16 and 10% turned out as active as the drug. In vivo, the treatment with the essential oil cured all infested rabbits and no statistical differences were observed with the treated control group.