Acaricidal activity of Derris floribunda essential oil and its main constituent

Objective: To evaluate the acaricidal activity of the essential oil obtained from roots of Derris floribunda(D. floribunda)(Miq.) Benth, and its main constituent nerolidol against the Mexican mite Tetranychus mexicanus(T. mexicanus)(Mc Gregor).Methods: The essential oil from the roots of D. floribunda collected in the Amazon region(Brazil) was obtained by hydrodistillation. Its chemical composition was determined by GC–MS analysis. The acaricidal activities of this essential oil and nerolidol,were evaluated by recording the number of dead females(mortality) and eggs(fertility).Results: The essential oil showed sesquiterpenes as major volatile components. Nerolidol, the main component, represented 68.5% of the total composition of the essential oil. D. floribunda essential oil and nerolidol showed acaricidal activity, with LC_(50) of9.61 mg/m L air and 9.2 mg/m L air, respectively, over a 72 h period. In addition, both the essential oil and nerolidol significantly reduced the fecundity of T. mexicanus.Conclusions: Due to the economic importance of T. mexicanus and the lack of new pesticides, our data are very promising in the search for efficient and safer acaricidal products. Furthermore, this is the first report about the chemical composition and bioactivity of the essential oil of the Amazon plant species D. floribunda.

Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus cirri was tested in the laboratory. Four solvents were used to prepare crude extracts, petroleum ether, chloroform, ethyl acetate, and ethanol, among which ethanol was the most effective one. The results suggested that ethanol extracts of B. sessilicarpa had eminent acaricidal and ovicidal activities. Concentrated extracts were prepared using petroleum ether, chloroform, ethyl acetate, or distilled water as solvent. Mite mortality rates in the concentrated extracts by petroleum ether, chloroform, or distilled water were significantly lower than those by ethyl acetate. The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL^-1, respectively. After liquid chromatography and thin layer chromatography, the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted. Fraction 2 was found to possess higher acaricidal and ovicidal activities. The mortality of eggs and adult mites were 85.83 and 63.07%, respectively. Moreover, fraction 2 showed moderate oviposition inhibition effect （0.8795） against P. citri when the used dose was higher than 2.5 mg mL^-1

Synthesis,Structure and Acaricidal Activity of Tricyclohexyltin Benzoate

Tricyclohexyltin 4-amino-3-methyl-benzoate （1） and tricyclohexyltin 3,4-dime- thoxybenzoate （2） were synthesized and their crystal structures were determined by X-ray diffraction. Compound 1 belongs to the monoclinic system, space group P21/c with a = 14.0554（15）, b = 11.6947（13）, c = 16.2720（17）A, Z = 4, V= 2565.7（5） A3, Dc = 1.341 g.cm-3,μ（MoKa） = 1.016 mm-1, F（000） = 1080, R = 0.0833 and wR = 0.2964. Compound 2 is of monoclinic system, space group C2/c with a = 17.8712（6）, b = 8.4433（3）, c = 35.5783（13） A, Z = 8, V= 5366.8（3） A3, Dc = 1.360 g.cm-3,/1（MoKa） = 0.980 mm-1, F（000） = 2288, R = 0.0549, wR = 0.1279. In compounds 1 and 2, the central Sn atom is coordinated in a tetradentate manner to assume a distorted tetrahedral configuration. Preliminary biological tests showed that these two compounds have strong acaricidal activity.

The thiazoylmethoxy modification on pyrazole oximes: Synthesis and insecticidal biological evaluation beyond acaricidal activity

A series of new pyrazole oximes bearing substituted thiazole ring were designed and prepared. The structures of the title compounds were identified by spectral analyses, The results of primary bioassay indicated that some targeted compounds exhibited promising insecticidal activity besides acaricidal activity, particularly; compounds 8c and 8d were more potent against Tetranychus cinnabarinus and Plutella xylostella than other analogues.

Synthesis and acaricidal activity of strobilurin-pyrimidine derivatives

Pyriminostrobin, a new acaricide, was discovered in our previous studies. Because introducing fluorine into organic compounds can increase bioactivity, pyriminostrobin was modified as a series of strobilurin-pyrimidine derivatives for biological screening. The compounds were characterized by 1H NMR, MS and elemental analysis. Preliminary bioassays demonstrated that compounds 7e and 7i exhibited significant control against Tetranychus cinnabarinus （Boisd.） at 0.625 mg L^-1, and their acaricidal potencies were higher than pyriminostrobin in a greenhouse. The relationship between structure and acaricidal activity was also studied.

Green synthesis,characterization,acaricidal,larvacidal,and repellent activities of copper nanoparticles of Astragalus sinicus against Hyalomma anatolicum

Objective:To green synthesize and characterize copper nanoparticles(Cu NPs)using Astragalus sinicus,as well as evaluate the acaricidal,larvacidal,and repellent activities of Cu NPs against Hyalomma anatolicum(H.anatolicum),one of the most prevalent ticks infesting cattle in Saudi Arabia.Methods:Cu NPs were green synthesized by adding the Astragalus sinicus extract to a copper sulfate solution.The acaricidal,larvicidal,and repellent activities of Cu NPs against H.anatolicum were assessed via the adult immersion test,the larval packet test,and the vertical movement behavior of tick larvae,respectively.The effects of Cu NPs on acetylcholinesterase as well as oxidative enzyme activities were examined.Results:The green synthesized Cu NPs displayed a spherical form with a size range of 15-75 nm.After exposure of adult H.anatolicum to different concentrations of Cu NPs,the viability rate of adult H.anatolicum and the mean number,weight,and hatchability of eggs were noticeably reduced,in comparison to the control group(P<0.001).In addition,the viability rate of larvae considerably declined(P<0.001)with the LC_(50)and LC_(90)values of 11.30 and 20.34μg/m L,respectively.The maximum repellent activity of Cu NPs was observed at 50,100,and 200μg/m L with complete repellent activity after 60,120,and 180 min of exposure,respectively.Cu NPs,mainly at 1/2 LC_(50)and LC_(50)concentrations,markedly suppressed the acetylcholinesterase activity of the larval stage of H.anatolicum(P<0.001).Moreover,Cu NPs,mainly at LC_(50)dose,significantly elevated malondialdehyde level while declining glutathione-S-transferase level in H.anatolicum larvae(P<0.001).Conclusions:Cu NPs show potent acaricidal,larvicidal,and repellent activities against adults and larvae of H.anatolicum.However,further studies must be performed to clarify the precise mechanisms and the efficacy of Cu NPs in practical use.

Synthetic derivatives of spiromesifen and their bioactivity research

Sixteen new derivatives of spiromesifen were synthesized from 3-（2,4,6-trimethylphenyl）-4-hydroxy-△^3-dihydrofuran-2-one. Their bioactivities against diamondbackmoth （Plutella xylostella） and spider mites （Tetranychus cinnabarinus） were also evaluated. The structures of these derivatives were confirmed by ^1H NMR, MS.

Bioactivity and Kinetic Study of <i>Jatropha curcas</i>Essential Oil Extraction Using Supercritical CO₂

This study reports the extraction of Jatropha curcas leaves using supercritical CO2. Experiments were performed varying the pressure (13 and 20 MPa) and the temperature (50°C and 60°C). The model of Sovová for supercritical fluid extraction was fitted to the experimental kinetic extraction curves. Two cell sizes were used and scale up equations compared. GC analysis showed phytol, carvacrol, and hexahydrofarnesyl acetone as major compounds in all the experiments. A maximum yield of 0.95% dry-weight basis was obtained. It was observed a maximum yield (0.95% dry-weight basis) extract obtained at 20 MPa and 50°C. The results indicated that the mass yield increased with the increase of pressure. The bioassays showed that the extract of J. curcas possessed toxicity against Hyalomma lusitanicum.

Synthesis analogues of milbemycin and their bioactivity evaluation

Eight new 13-O-aminocarbonylivermectin aglycones and 4＇-O-aminocarbonylivermectin monosaccharide were synthesized from ivermectin agiycone and ivermectin monosaccharide by the selective protection of C5-OH group.Their bioactivities were evaluated against spider mites（Tetranychus cinnabarimts）,aphid（Aphis fabae） and oriental armyworm（Mytliimma sepatara）. Their structures were confirmed by ^1H NMR.MS.

Synthesis of New 13-O-Acylavermectin Bl Aglycones

Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae.

Synthesis of Trihydrocarbyltin Chloride Containing Silicon and Crystal Structure of (p-Cl-C_6H_4Me_2SiCH_2)_3SnCl

A series of trihydrocarbyltin chlorides containing silicon was synthesized. The acaricidal activity was determined and the structure activity relationship was tried to be found out with the hydrophobic parameter.

Synthesis and bioactivity of novel pyrazole oxime derivatives containing oxazole ring

A series of novel pyrazole oxime derivatives containing oxazole ring were designed and synthesized. The title compounds were structurally confirmed by 1H NMR, 13C NMR spectra and elemental analyses. Preliminary bioassay results showed that some of the title compounds displayed promising fungicidal activity besides insecticidal and acaricidal activity. Particularly, compound 8c exhibited potent fungicidal activity against cucumber Pseudoperonospora cubensis beyond good insecticidal activity against Aphis craccivora and Nilaparvata lugens.