Fumigant toxicity of cassia and cinnamon oils and cinnamaldehyde and structurally related compounds to Dermanyssus gallinae (Acari: Dermanyssidae)

The toxicity of two cassia oils, four cinnamon oils and (E)-cinnamaldehyde and (E)-cinnamic acid and 34 structurally related compounds to adult Dermanyssus gallinae (De Geer) collected from a poultry house was examined using a vapour-phase mortality bioassay. Results were compared with those of dichlorvos, a conventional acaricide. The cassia and cinnamon oils (cinnamon technical, cinnamon #500, cassia especial, cassia true, cinnamon bark and cinnamon green leaf) exhibited good fumigant toxicity (LD(50), 11.79-26.40 μg cm(-3)). α-Methyl-(E)-cinnamaldehyde (LD(50), 0.45 μg cm(-3)) and (E)-cinnamaldehyde (0.54 μg cm(-3)) were the most toxic compounds and the toxicity of these compounds was comparable to that of dichlorvos (0.30 μg cm(-3)). Potent fumigant toxicity was also observed in allyl cinnamate, ethyl-α-cyanocinnamate, (E)-2-methoxylcinnamic acid and (Z)-2-methoxylcinnamic acid (LD(50), 0.81-0.92 μg cm(-3)). Structure-activity relationships indicate that structural characteristics, such as types of functional groups and carbon skeleton rather than vapour pressure parameter, appear to play a role in determining toxicity. The essential oils and compounds described merit further study as potential acaricides for the control of D. gallinae populations as fumigants with contact action due to global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment.     

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.     

In vitro investigation of the toxic effects of extracts of Allium sativum bulbs on adults of Hyalomma marginatum rufipes and Rhipicephalus pulchellus

The toxic effects of the extracts of Allium sativum (Garlic) were evaluated against adults of Hyalomma marginatum rufipes and Rhipicephalus pulchellus using three types (Types A, B and C) of contact toxicity bioassays. A. sativum bulbs were extracted with acetone, ethanol and dichloromethane (DCM) solvents. Among these three solvents, it is the DCM extract of A. sativum that appears to have anti-tick activity. In the Type A contact toxicity bioassay, DCM extracts of A. sativum demonstrated a high acaricidal bioactivity against H. m. rufipes with 100% of ticks killed in less than an hour, and toxicity persisted to the second day. A weak acaricidal activity of aqueous extracts of A. sativum was observed in the Type B contact toxicity bioassay. In the Type C contact toxicity bioassay, a concentration of 24% w/v of DCM extracts of garlic in sunflower oil (Helianthus annuus) had killed 100% of H. m. rufipes (LC50 = 5.9% w/v) and R. pulchellus (LC50 = 10.3% w/v) by 24 hours post-treatment of ticks. The results obtained from this study suggest that DCM extract of A. sativum is a potential source of novel acaricidal agents.     

In vitro acaricidal effect of tannin-rich plants against the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

The objectives of this study were to evaluate the in vitro acaricidal effects of lyophilized extracts of four tannin rich plants (Acacia pennatula, Piscidia piscipula, Leucaena leucocephala and Lysiloma latisiliquum) against diverse stages of Rhipicephalus (Boophilus) microplus, and to asses whether tannins were involved in the acaricidal effect using polyethylene glycol (PEG) to block tannins. Larval immersion (LIT) and adult immersion (AIT) tests were used to evaluate the acaricidal effect of each of the lyophilized extracts against larval and adult stages of R. microplus respectively. Larvae and adult ticks were exposed to increasing concentrations of each plant extract (0, 1200, 2400, 4800, 9600 and 19,200 μg ml(-1)) for 10 min. Larval mortality was recorded at 48 h post-incubation. Adult mortality was recorded daily over 14 days, at which point their reproductive efficiency was evaluated. PEG was added to the extracts to verify whether tannins were involved in the acaricidal effect. The effect on egg laying inhibition and larval mortality was analyzed using the GLM procedure in SAS. A Kruskal-Wallis test was used to assess the effect of PEG on LIT results. Calculation of the lethal concentration 50 (LC50) was performed using a probit analysis. All extracts reduced the viability of R. microplus larval stages (P<0.001), and viability was restored with the addition of PEG suggesting an important role of tannins in the acaricidal effect (P<0.001). The LC50 values of L. latisiliquum and P. piscipula plant extracts were 6.402 and 2.466 μg ml(-1). None of the tannin-rich plant extracts affected adult mortality (P>0.05). Lysiloma latisiliquum extract inhibited egg hatching of R. microplus (P<0.01). Tannin-rich plant extracts from A. pennatula, P. piscipula, L. leucocephala and L. latisiliquum showed potential acaricidal activity. Further in vivo studies are needed to confirm this finding.     

Toxicity of essential and non-essential oils against the chewing louse, Bovicola (Werneckiella) ocellatus

The toxicity of six plant essential oils to the chewing louse, Bovicola (Werneckiella) ocellatus collected from donkeys, was examined in laboratory bioassays. The oils examined were: tea-tree (Melaleuca alternifolia), lavender (Lavandula angustifolia), peppermint (Mentha piperita), eucalyptus (Eucalyptus globulus Labillardiere), clove bud (Eugenia caryophyllata) and camphor (Cinnamomum camphora). All except camphor oil showed high levels of toxicity, with significant dose-dependent mortality and an LC(50) at concentrations of below 2% (v/v). Hundred percent mortality was achieved at concentrations of 5-10% (v/v). Two essential oil components: eugenol and (+)-terpinen-4-ol showed similar levels of toxicity. The data suggest that these botanical products may offer environmentally and toxicologically safe, alternative veterinary pediculicides for the control of ectoparasitic lice.     

Acaricidal activity of Palicourea marcgravii, a species from the Amazon forest, on cattle tick Rhipicephalus (Boophilus) microplus

Leaves of Palicourea marcgravii were extracted successively with hexane, ethyl acetate and ethanol in order to evaluate their acaricidal activity on larvae and adult stages of the cattle tick Rhipicephalus (Boophilus) microplus. The ethyl acetate extract showed the highest bioactivity of the tested extracts, which contained 0.12% monofluoroacetic acid. On engorged female, the ethyl acetate extract showed a lethal concentration 50% - LC(50)=30.08 mg ml(-1), inhibitory concentration 50% - IC(50)=5.79 mg ml(-1) and lethal time 50% - LT(50)=4.72 days; 100% reproduction was controlled at concentrations of 50 mg ml(-1) and on larvae the ethyl acetate extract showed a LC(50)=2.46 mg ml(-1). No alkaloids were detected in any of the extracts. This is the first report on the acaricidal activity of P. marcgravii extracts against R. microplus as well as the acaricidal properties of a plant species containing monofluoroacetic acid.     

Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro

The acaricidal activity of the petroleum ether extract, the chloroform extract and the acetic ether extract of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests. The results showed that at all test time points, the petroleum ether extract demonstrated the highest activity against the larvae of S. scabiei var. cuniculi, while the activities of the chloroform extract and the acetic ether extract were similar. The activities of both the petroleum ether extract and the chloroform extract against the larvae showed the relation of time and concentration dependent. The median lethal concentration (LC(50)) of the petroleum ether extract (1.3muL/mL) was about three times that of the chloroform extract (4.1muL/mL) at 24h post-treatment. At the concentrations of 500.0muL/mL, the median lethal time (LT(50)) of the petroleum ether extract and the chloroform extract was 8.4 and 9.6h, respectively.     

藏兽药蓝花侧金盏对兔螨的抑杀作用研究

目的:探讨藏兽药蓝花侧金盏对兔螨的抑杀作用。方法:应用体外培养杀螨实验,比较了蓝花侧金盏水提取物、甲醇提取物、乙酸乙酯提取物及石油醚提取物的杀螨活性,并对活性较强的提取物的毒力和治疗兔螨病效果进行了评价。结果:4种提取物中,乙酸乙酯提取物具有较强的体外杀螨活性,高剂量(500 mg/mL)在体外培养6 h内全部杀死螨虫,4种浓度(500、250、125和62.5 mg/mL)的半数致死时间分别为0.743、2.73、5.919和22.536 h,并且其能有效治疗兔螨病,总有效率为90%。结论:蓝花侧金盏乙酸乙酯提取物具有良好的杀兔螨活性。     

黄帚橐吾乙醇提取物对小鼠的急性毒性试验

黄帚橐吾(Ligularia virgaurea)是一种在甘南草原上广泛分布的毒杂草,但同时其乙醇提取物有很强的生物农药活性,具备开发成为生物农药的潜力。本研究通过昆明小鼠(Mus musculus)的经皮、经口急性毒性试验对黄帚橐吾乙醇提取物的安全性进行评估。结果显示,黄帚橐吾乙醇提取物对小鼠的经皮急性毒性半致死剂量LD5030g·kg-1,经口急性毒性LD50为6.983 1g·kg-1,均符合低毒农药登记的毒性标准,可以按照低毒农药进行开发应用。     

Ovicidal and larvicidal activity of Melia azedarach extracts on Haemonchus contortus

Haemonchus contortus is responsible for severe economic losses in sheep and goat breeding in the Northeast of Brazil. However, the effectiveness of control is compromised due to anthelmintic resistance and misuse. In the search for natural anthelmintics, Melia azedarach L., a plant indigenous to India but now distributed throughout Brazil, was selected due to the reported anthelmintic properties of its seeds. The aim of this study was to evaluate the anthelmintic activity of the seed and leaf extracts of the Brazilian adapted plant and investigate the type of organic chemical compounds present in the most active extracts. The ovicidal and larvicidal activity of M. azedarach extracts on H. contortus was evaluated through egg hatching and larval development tests. Hexane and ethanol extracts of seeds and chloroform and ethanol extracts of leaves of M. azedarach were used in the tests. To perform the larval development test, feces of an animal free from parasites were mixed with third instar H. contortus larvae and extracts in several concentrations. The coprocultures were incubated for 7 days at 30 degrees C, then the larvae were recovered and counted. LC50 was calculated by probits using the SPSS 8.0 program. The seed ethanol extract was the most active on eggs (LC50=0.36mgmL(-1)) and the leaf ethanol extract showed the best inhibition of larval development (LC50=9.18mgmL(-1)). Phytochemical analysis of the most active extracts revealed the presence of condensed tannins, triterpenes and alkaloids.     

Anthelmintic and cytotoxic activities of extracts of Markhamia obtusifolia Sprague (Bignoniaceae)

The anthelmintic activity of Markhamia obtusifolia Sprague (Bignoniaceae) leaf extracts was evaluated against the ruminant gastrointestinal nematode parasite Trichostrongylus colubriformis (Nematoda: Strongylida) using the in vitro egg hatch test. Also, the cytotoxic activity of aqueous extracts of M. obtusifolia was evaluated in cell line cytotoxicity assays. The results indicated that the effective concentration (EC(50)) for the water extract of M. obtusifolia leaves (0.46 mg/mL; Confidence Interval [CI] 0.3-0.5mg/mL) was significantly lower than the EC(50) for the acetone extract of M. obtusifolia (0.8 mg/mL; CI 0.7-1mg/mL). Aqueous extracts were twice as potent as the acetone extracts. The EC(90) (0.2mg/mL; CI 0.1-0.02) for thiabendazole (positive control) was significantly lower than the EC(90) for the water extract of M. obtusifolia (10.7 mg/mL; CI 8.3-13.7 mg/mL). In the cytotoxicity bioassay, the lethal concentration (LC(50)) for the aqueous extract of M. obtusifolia was 0.476 mg/mL, which was relatively high (low toxicity) in comparison to the highly toxic berberine (LC(50)=9.80 μg/mL). The current study showed that M. obtusifolia plant extracts possess anthelmintic activity and are relatively non-cytotoxic, thus providing support for their use in traditional veterinary practices.     

The acute toxicity of the death camas (Zigadenus species) alkaloid zygacine in mice, including the effect of methyllycaconitine coadministration on zygacine toxicity

Death camas (Zigadenus spp.) is a common poisonous plant on foothill rangelands in western North America. The steroidal alkaloid zygacine is believed to be the primary toxic component in death camas. Poisonings on rangelands generally occur in the spring when death camas is abundant, whereas other more desirable forage species are limited in availability. In most cases where livestock are poisoned by plants in a range setting, there is more than one potential poisonous plant in that area. One common poisonous plant that is often found growing simultaneously in the same area as death camas is low larkspur (Delphinium nuttallianum). Consequently, the objectives of this study were to conduct acute toxicity studies in mice and to determine if coadministration of low larkspur will exacerbate the toxicity of death camas. We first characterized the acute toxicity of zygacine in mice. The LD(50) of zygacine administered intravenously (i.v.) and orally was 2.0 ± 0.2 and 132 ± 21 mg/kg, respectively. The rate of elimination of zygacine from whole blood was determined to be 0.06 ± 0.01/min, which corresponds to an elimination half-life of 13.0 ± 2.7 min. The i.v. LD(50) of total alkaloid extracts from a Utah and a Nevada collection were 2.8 ± 0.8 and 2.2 ± 0.3 mg/kg, respectively. The i.v. LD(50) of methyllycaconitine (MLA), a major toxic alkaloid in low larkspur, was 4.6 ± 0.5 mg/kg, whereas the i.v. LD(50) of a 1:1 mixture of MLA and zygacine was 2.9 ± 0.7 mg/kg. The clinical signs in mice treated with this mixture were very similar to those of mice treated with zygacine alone, including the time of onset and death. These results suggest that there is an additive effect of coadministering these 2 alkaloids i.v. in mice. The results from this study increase knowledge and understanding regarding the acute toxicity of death camas. As combined intoxications are most likely common, this information will be useful in further developing management recommendations for ranchers and in designing additional experiments to study the toxicity of death camas to livestock.     

秃疮花水溶性制剂的毒性试验

为了确定秃疮花水溶性制剂的临床应用剂量,用甘肃省畜牧兽医研究所研制的秃疮花水溶性制剂,以局部毒性法、Reed-Muensch法和寇氏Karber法,进行了动物皮肤刺激试验和犊牛睾丸细胞、鸡胚及小鼠的半数致死量( LD50)试验.试验表明,秃疮花水溶性制剂对动物皮肤无刺激;对犊牛睾丸细胞、鸡胚和小鼠的LD50分别为0.4...     

Efficacy of Strychnos spinosa (Lam.) and Solanum incanum L. aqueous fruit extracts against cattle ticks

The efficacy of Solanum incanum and Strychnos spinosa aqueous fruit extracts was evaluated against cattle ticks in on-station experiments and laboratory tick bioassays. In the on-station experiment using cattle, fruit extracts were applied at three concentrations 5, 10, and 20 % (w/v) and compared with a commercial acaricide, Tickbuster® (amitraz) spray (positive control) and no treatment (negative control). The treatments were applied at weekly intervals for 6 weeks as surface sprays on 32 Mashona cattle in a completely randomized design experiment. Ticks on individual cattle were identified, counted, and recorded daily. Peripheral blood samples were collected for parasite screening. In the laboratory, tick bioassays were conducted at four concentrations, 5, 10, 20, and 40 % (w/v) fruit extracts compared to Tickbuster® (amitraz) spray (positive control) and distilled water (negative control). The extracts were incubated with Rhipicephalus (Boophilus) decoloratus tick larvae and mortalities for each treatment level recorded after 24 and 48 h. The 5 % Solanum incanum treatment had higher efficacy ratio (P?<?0.05) than the other fruit extract concentrations of the same plant species. Efficacy ratio was higher (P?<?0.05) in the 5 % S. spinosa-treated cattle than in the untreated control but lower (P?<?0.05) than that for the amitraz treatment. The bioassays indicated that there was a high efficacy ratio for the lowest fruit extract concentrations when ticks were exposed to acaricidal treatments for 48 h compared to 24 h. Overall, the results indicate that Solanum incanum and Strychnos spinosa individually have some acaricidal effect.     

NAS制剂毒理学研究

为了评价NAS制剂的毒性,以小白鼠、雏鸡进行了毒理学试验研究。急性毒性试验结果表明,小鼠口服NAS中草药制剂的LD50为（9．0573±0.0309）g／kg。亚慢性毒性试验结果表明,3个剂量组（1．8g／kg,0．45s／ks,0．15s／ks）雏鸡连续口服NAS中草药制剂14d,1次／d,未出现中毒症状,而显示出有增重作用,且增重率与药物剂量成正比,即高剂量组〉中剂量组〉低剂量组。     

The effect of 7,8-methylenedioxylycoctonine-type diterpenoid alkaloids on the toxicity of methyllycaconitine in mice

Larkspur plants contain numerous norditerpenoid alkaloids, which include the 7,8-methylenedioxylycoctonine (MDL)-type alkaloids and the N-(methylsuccinimido)anthranoyllycoctonine (MSAL)-type alkaloids. The MSAL-type alkaloids are generally much more toxic (typically >20 times). Toxicity of many tall larkspurs, such as Delphinium barbeyi, has been attributed to its large concentration of MSAL-type alkaloids, including methyllycaconitine (MLA). However, the norditerpenoid alkaloids found in the greatest concentrations in most D. barbeyi populations are either deltaline or 14-O-acetyldictyocarpine (14-OAD), both less toxic MDL-type alkaloids. Although the individual toxicities of MLA, 14-OAD, and deltaline have been determined, the impact (additive or antagonistic) that large concentrations of deltaline or 14-OAD in the plant have on the toxicity of MLA is unknown. Consequently, the effect of MDL-type alkaloids on the toxicity of MLA was compared by using median lethal dose (LD(50)) and toxicokinetic profiles of the brainand muscle from mice receiving i.v. administration of these alkaloids, individually or in combination, at ratios of 1:1, 1:5, and 1:25 MLA to MDL-type alkaloids. The LD(50) for MLA alone was 4.4 +/- 0.7 mg/kg of BW, whereas the coadministration of MLA and deltaline at 1:1, 1:5, and 1:25 resulted in an LD(50) of 2.7, 2.5, and 1.9 mg/kg of BW, respectively. Similarly, the coadministration of MLA and 14-OAD at 1:1, 1:5, and 1:25 resulted in an LD(50) of 3.1, 2.2, and 1.5 mg/kg of BW, respectively. Coadministration of mixtures did not result in increased MLA bioavailability or alterations in clearance from the brain and muscle. Consequently, the increased toxicity of the mixtures was not a result of increased MLA bioavailability (based on the maximum concentrations observed) or alterations in MLA clearance from the brain and muscle, because these were unchanged. These results demonstrate that MDL-type alkaloids have an additive effect on MLA toxicity in mice and may also play a role in the overall toxicity of tall larkspur plants in cattle.     

4种中药单体物质的体外杀螨活性

以苦参碱、对叶百部碱、瑞香素、青蒿素为试验用药,采用浸杀方式测定中药单体对免疥螨幼虫的离体杀螨活性,并测定最强杀螨活性药物的半数致死浓度（Median lethal concentration,LC5。）和半数致死时间（Median lethal time,LT50）。结果显示,在药物质量浓度为10．00g／L时,苦参碱、对叶百部碱、瑞香素和青蒿素的起效时间分别为45．00、127．50、165．00、263．50min,全部死亡时间分别为1455．00、1890．00、2130．00、2280．00min。质量浓度为25．00g／L的苦参碱在试验24h时的LC50为2．86g／L;质量浓度为25．00、12．50、6．25g／L的苦参碱LT5。分别为7．54、9．85、14．55h。结果表明,4种中药单体都具有一定的体外杀螨活性,其中苦参碱的蒂螨活性最强,对叶百部碱和瑞香素次之,青蒿素杀螨活性最弱。     

In vitro anthelmintic, antibacterial and cytotoxic effects of extracts from plants used in South African ethnoveterinary medicine

Many plants are used for ethnoveterinary purposes in South Africa, particularly in rural areas. Extracts of 17 plant species employed to treat infectious diseases were prepared using three solvents and the antibacterial activity of the extracts was determined against two Gram-positive and two Gram-negative bacteria. Anthelmintic activity was evaluated against the free-living nematode Caenorhabditis elegans and toxicity was determined using the brine shrimp larval mortality test. Most of the plant extracts demonstrated antibacterial activity, with the best minimum inhibitory concentration (MIC) being 0.1 mg mL(-1). More than a third of the extracts displayed anthelmintic activity. Toxic effects against brine shrimp larvae were shown by 30% of extracts, with the lowest LC(50) recorded as 0.6 mg mL(-1). The promising biological activity displayed by a number of plant extracts supports the ethnoveterinary use of these plants but in vivo tests are required to ascertain fully their medicinal properties and potential toxicity.     

Toxicity of seeds of three Aesculus spp to chicks and hamsters

Seeds of horse chestnut (Aesculus hippocastanum), Ohio buckeye (A glabra), and yellow buckeye (A octandra) were tested for toxicity to 2-week-old Leghorn chicks and adult female Syrian hamsters. The LD50 of the water soluble portion of alcoholic extracts of horse-chestnut seeds (for hamsters and chicks) and of dried, powdered seeds (chicks only) was determined. The LD50 for a single dose of extract from horse-chestnut seeds was 10.6 mg/g of body weight for chicks and 10.7 mg/g of body weight for hamsters. The LD50 for chicks given 2 consecutive daily doses of horse-chestnut seed was 6.5 mg/g. Toxic signs included depression, muscular incoordination, paralysis, coma, and death. Extracts of seeds of Ohio buckeye were nontoxic to chicks and hamsters when fed at 80 mg/g. One of 5 hamsters died after dosing for 5 days with 80 mg/g of extract of seeds of yellow buckeye/g.     

Influence of light and darkness on the behaviour of Dermanyssus gallinae on layer farms

The behaviour of Dermanyssus gallinae was investigated on two layer farms where two different light programs were introduced in the 40th week of hen life. In layer house No. 1, light was applied continuously for 16 hours during the day, while layer house No. 2 was subjected to 4 hours of light and 2 hours of darkness applied alternately during the day. To monitor the level of red mite infestation, 30 tube traps were placed in every layer house corridor at a height of 1.5 m above the floor. In the first layer house, 280 Dermanyssus gallinae females, 50 nymph larvae and 198 eggs were found in 100 mg of tube trap material during 16 hours of the light phase, while during the 8-hour darkness phase, 1240 females, 70 nymph larvae and 110 eggs were collected. In the other layer house (with an alternating light phase of 4 hours and a darkness phase of 2 hours per day), 387 Dermanyssus gallinae females, 401 nymph larvae and 1060 eggs were found in trap tubes over the 8-hour dark phase, while 343 females, 202 nymph larvae and 1106 eggs were discovered over the 16-hour light phase.