Sha Sha Chu

Chemical Composition and Insecticidal Activity against Sitophilus zeamais of the Essential Oils of Artemisia capillaris and Artemisia mongolica

In our screening program for new agrochemicals from local wild plants, Artemisia capillaris and A. mongolica were found to possess insecticidal activity against the maize weevil, Sitophilus zeamais. The essential oils of aerial parts of the two plants were obtained by hydrodistillation and were investigated by GC and GC-MS. The main components of A. capillaris essential oil were 1,8-cineole (13.75%), germacrene D (10.41%), and camphor (8.57%). The main constituents of A. mongolica essential oil were α-pinene (12.68%), germacrene D (8.36%), and γ-terpinene (8.17%). Essential oils of A. capillaris and A. mongolica possess fumigant toxicity against S. zeamais adults with LC50 values of 5.31 and 7.35 mg/L respectively. The essential oils also show contact toxicity against S. zeamais adults with LD50 values of 105.95 and 87.92 μg/adult, respectively.

Insecticidal Activity and Chemical Composition of the Essential Oils of Artemisia lavandulaefolia and Artemisia sieversiana from China

In our screening program for new agrochemicals from local wild plants, Artemisia lavandulaefolia and A. sieversiana were found to possess insecticidal activity against the maize weevil Sitophilus zeamais. The essential oils of the aerial parts of the two plants were obtained by hydrodistillation and analyzed by GC and GC/MS. The main components of A. lavandulaefolia oil were caryophyllene (15.5%), β‐thujone (13.8%), eucalyptol (13.1%), and β‐farnesene (12.3%), and the principal compounds identified in A. sieversiana oil were eucalyptol (9.2%), geranyl butyrate (9.2%), borneol (7.9%), and camphor (7.9%). The essential oils of A. lavandulaefolia and A. sieversiana possessed fumigant toxicity against S. zeamais adults with LC50 values of 11.2 and 15.0 mg/l air, respectively. Both essential oils also showed contact toxicity against S. zeamais adults with LD50 values of 55.2 and 112.7 μg/adult, respectively.

Toxicity of Schizonpeta multifida essential oil and its constituent compounds towards two grain storage insects

BACKGROUND The essential oil derived from the flowering aerial parts of Schizonpeta multifida was investigated for insecticidal activity against two grain storage insects, maize weevil (Sitophilus zeamais) and red flour beetle (Tribolium castaneum). RESULTS The main constituents of the essential oil were menthone (40.34%) and pulegone (26.87%), followed by D-limonene (5.81%) and isomenthone (5.14%). Bioactivity-directed chromatographic separation on repeated silica gel columns led to the isolation of menthone and pulegone. Pulegone showed pronounced contact toxicity against S. zeamais and T. castaneum adults (7 day LD(50)= 4.46 and 1.55 µg per adult respectively) and was more toxic than menthone (7 day LD(50)=33.47 and 2.67 µg per adult respectively), while the crude essential oil had 7 day LD(50) values of 30.17 and 2.75 µg per adult respectively. Pulegone also displayed strong fumigant toxicity against S. zeamais and T. castaneum adults (7 day LC(50)=3.47 and 11.56 mg cm(-3) respectively) and was again more toxic than menthone (7 day L(50) =10.32 and 31.25 mg cm(-3) respectively), while the crude essential oil had 7 day LC(50) values of 8.33 and 26.41 mg cm(-3) respectively. CONCLUSION The essential oil of S. multifida and its two main components may have potential to be developed as new natural fumigants/insecticides for the control of stored product insects.

Insecticidal compounds from the essential oil of Chinese medicinal herb Atractylodes chinensis

BACKGROUND In a screening programme for new agrochemicals from Chinese medicinal herbs, the essential oil of Atractylodes chinensis (DC.) Koidz was found to possess strong insecticidal activity against the common vinegar fly, Drosophila melanogaster L. The essential oil was extracted via hydrodistillation, and its constituents were determined by GC-MS analysis. RESULTS The main components of A. chinensis essential oil were β-eudesmol (21.05%), β-selinene (11.75%), γ-elemene (7.16%) and isopetasam (5.36%). Bioactivity-directed chromatographic separation on repeated silica gel columns led to the isolation of five compounds, namely atractylon, α-elemol, β-eudesmol, hinesol and β-selinene. β-Selinene, α-elemol and hinesol showed pronounced contact toxicity against D. melanogaster adults, with LD(50) values of 0.55, 0.65 and 0.71 µg adult(-1) respectively. Atractylon and β-eudesmol were also toxic to the fruit flies (LD(50) = 1.63 and 2.65 µg adult(-1) respectively), while the crude oil had an LD(50) value of 2.44 µg adult(-1) . CONCLUSION The findings suggested that the essential oil of Atractylodes chinensis and its active constituents may be explored as natural potential insecticides.

Feeding Deterrents from Zanthoxylum schinifolium against Two Stored-Product Insects

Screening for insecticidal principles from several Chinese medicinal herbs showed that the fruit pericarp of Zanthoxylum schinifolium possessed significant feeding deterrence against two stored-product insects (Tribolium castaneum and Sitophilus zeamais). From the methanol extract, two feeding deterrents were isolated by bioassay-guided fractionation. The compounds were identified as schinifoline and skimmianine from their spectroscopic data. Schinifoline has feeding deterrent activity against T. castaneum and S. zeamais adults with EC(50) values of 47.8 and 85.6 ppm respectively. Skimmianine possess feeding deterrent activity against T. castaneum and S. zeamais adults with EC(50) values of 75.7 and 129.7 ppm respectively.

Insecticidal Components from the Essential Oil of Chinese Medicinal Herb, Ligusticum chuanxiong Hort

Essential oil of Chinese medicinal herb, Ligusticum chuanxiong dried rhizome was found to possess insecticidal activity against maize weevils, Sitophilus zeamais. The main components of L. chuanxiong essential oil were Z-3-butylidenephthalide (20.56%), Z-ligustilide (19.61%), 4-terpinenol (8.82%), 4-vinylguaiacol (6.81%) and α-selinene (6.01%). Bioactivity-guided chromatographic separation of the essential oil on repeated silica gel columns led to isolate three compounds namely 3-butylidenephthalide, Z-ligustilide and 4-vinylguaiacol. Z-liqustilide and Z-3-butylidenephthalide showed pronounced toxicity against S. zeamais (LD50= 10.23 and 15.81 μg/adult respectively) and were more toxic than 4-vinylguaiacol (LD50 = 63.75 μg/adult). The crude essential oil also possessed contact toxicity against S. zeamais (LD50 = 13.09 μg/adult).

Insecticidal activity of the root bark essential oil of Periploca sepium Bunge and its main component

During our screening programme for agrochemicals from Chinese medicinal herbs, the root bark essential oil of Periploca sepium was found to possess strong contact toxicity against the fruit flies, Drosophila melanogaster with a LD50 value of 1.22 µg/adult. The main component of the essential oil was identified to be 2-hydroxy-4-methoxy-benzaldehyde (78.8%), followed by linalool (2.8%) and (−)-α-terpineol (2.7%). The 2-hydroxy-4-methoxy-benzaldehyde was further isolated and identified by bioassay-directed fractionation. The compound showed strong contact toxicity against D. melanogaster and the maize weevil (Sitophilus zeamais) with LD50 values of 1.47 and 6.99 µg/adult, respectively.

GC-MS analysis of insecticidal essential oil of flowering aerial parts of Saussurea nivea Turcz

BackgroundSeveral species from Saussurea have been used in the traditional medicine, such as S. lappa, S. involucrate, and S. obvallata. There is no report on medicinal use of S. nivea. The aim of this research was to determine chemical composition and insecticidal activity of the essential oil of S. nivea Turcz (Asteraceae) aerial parts against maize weevils (Sitophilus zeamais Motschulsky) for the first time.ResultsEssential oil of S. nivea flowering aerial parts was obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC-MS). A total of 43 components of the essential oil of S. nivea were identified. The principal compounds in the essential oil were (+)-limonene (15.46%), caryophyllene oxide (7.62%), linalool (7.20%), α-pinene (6.43%), β-pinene (5.66%) and spathulenol (5.02%) followed by β-eudesmoll (4.64%) and eudesma-4,11-dien-2-ol (3.76%). The essential oil of S. nivea exhibited strong contact toxicity against S. zeamais with an LD50 value of 10.56 μg/adult. The essential oil also possessed fumigant toxicity against S. zeamais with an LC50 value of 8.89 mg/L.ConclusionThe study indicates that the essential oil of S. nivea flowering aerial parts has a potential for development into a natural insecticide/fumigant for control of insects in stored grains.

Chemical composition and insecticidal activity of the essential oil of Amethystea caerulea L.

The essential oil of the aerial parts of Amethystea caerulea L. was obtained from steam distillation and investigated by GC and GC-MS. The main components of the essential oil were morrilol (25.1%), 4-vinylguaiacol (14.3%) and acetoanisole (14.3%), followed by linalool (6.6%), eugenol (5.8%) and α-caryophyllene (5.2%). The essential oil showed pronounced contact toxicity against Drosophila melanogaster L. and maize weevil, Sitophilus zeamais (Motsch.), with LD50 values of 5.18 and 50.45 µg per adult, respectively. The essential oil also possessed strong fumigant toxicity against the maize weevils with an LC50 value of 25.39 µg mL−1.