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Water-distilled essential oil from Clinopodium chinense (Labiatae) aerial parts at the flowering stage was analyzed by gas chromatography-mass spectrometry. Thirty-five compounds, accounting for 99.18% of the total oil, were identified, and the main components of the essential oil of C. chinense were spathulenol (18.54%), piperitone (18.9%), caryophyllene (12.04%), and bornyl acetate (8.14%). Based on bioactivity-directed fractionation, bornyl acetate, caryophyllene, and piperitone were identified from the essential oil. The essential oil possessed fumigant toxicity against booklice (Liposcelis bostrychophila) with a 50% lethal concentration (LC50) value of 423.39 μg/liter, while the isolated constituents, bornyl acetate and piperitone, had LC50 values of 351.69 and 311.12 μg/liter against booklice, respectively. The essential oil also exhibited contact toxicity against L. bostrychophila with an LC50 value of 215.25 μg/cm(2). Bornyl acetate, caryophyllene, and piperitone exhibited acute toxicity against booklice with LC50 values of 321.42, 275.00, and 139.74 μg/cm(2), respectively. The results indicated that the essential oil and its isolated constituents have potential for development into natural insecticides or fumigants for control of insects in stored grains.

BACKGROUND In our screening programme for new agrochemicals from wild plants, the essential oil of Tetradium glabrifolium (Champ. ex Benth.) T.G. Hartley fruits was found to possess strong larvicidal activity against the Asian tiger mosquito, Aedes albopictus L. The essential oil was extracted via hydrodistillation, and the constituents were determined by GC-MS analysis. The active compounds were isolated and identified by bioassay-directed fractionation. RESULTS GC-MS analyses revealed the presence of 19 components with 2-tridecanone (43.38%), 2-undecanone (24.09%), D-limonene (13.01%), caryophyllene (5.04%) and β-elemene (4.07%) being the major constituents. Bioactivity-directed chromatographic separation of the oil led to the isolation of 2-tridecanone, 2-undecanone and D-limonene as active compounds. The essential oil of T. glabrifolium exhibited larvicidal activity against the early fourth-instar larvae of A. albopictus, with an LC50 value of 8.20 µg mL−1. The isolated constituent compounds, 2-tridecanone, 2-undecanone and D-limonene, possessed strong larvicidal activity against the early fourth-instar larvae of A. albopictus, with LC50 values of 2.86, 9.95 and 41.75 µg mL−1 respectively. CONCLUSION The findings indicated that the essential oil of T. glabrifolium fruits and the three constituents have an excellent potential for use in control of A. albopictus larvae and could be useful in the search for newer, safer and more effective natural compounds as larvicides. © 2014 Society of Chemical Industry

The starch/lactic acid grafting copolymer has been prepared by one-step reaction of corn starch with lactic acid catalyzed with sulfuric acid, and the structure of product was characterized by IR, XRD, SEM and1H-NMR. The experimental results showed that sulfuric acid could catalyze the graft copolymerization of starch with lactic acid, and the grafting degree of starch could reach 55.4%.

Purpose: To determine the insecticidal properties of essential oil from Mosla soochowensis aerial parts against two insect pests, Sitophilus zeamais and Tribolium castaneum . Methods: Hydro-distillation of M. soochowensis was used to extract the essential oil. Gas chromatography/mass spectrometry (GC/MS) analysis was performed, and the contact (topical application) and fumigant toxicity (sealed space) of the essential oil were evaluated. Results: Thirty-nine chemical compounds were identified by GC-MS analysis of M. soochowensis essential oil. The major components are β-caryophyllene (12.82 %), spatulenol (6.34 %), β-eudesmol (6.26 %), carvone (6.12 %), α-thujone (5.12 %), γ-eudesmol (4.86 %), α-cedrol (4.23 %), and α- caryophyllene (4.04 %). The plant essential oil exerted contact toxicity against adults of S. zeamais and T. castaneum (median lethal concentration (LC 50 ), 25.45 and 10.23 μg/adult, respectively). Moreover, the essential oil exhibited pronounced fumigant toxicity towards adults of both species (LC 50 12.19 and 10.26 mg/L air, respectively). Conclusion: These results show that M. soochowensis essential oil can be used in development of safer and more natural and effective fumigants/insecticides for stored products. Keywords: Mosla soochowensis , Contact toxicity, Sitophilus zeamais , Fumigant, Insecticide, Essential oil, Tribolium castaneum

Purpose: To investigate contact and fumigant toxicity of the essential oil of Bidens frondosa and its isolated constituents against booklice ( Liposcelis bostrychophila ). Methods: The essential oil of B. frondosa was obtained by hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) with HP-5MS column. The active constituents were purified from the oil by bioactivity-guided fractionation. Contact (impregnated filter paper method) and fumigant toxicity (sealed space) of the oil and its isolates were determined. Results: Thirty-two compounds, representing 98.88 % of the total oil, were determined and the major constituents of the essential oil were caryophyllene oxide (20.50 %), borneol (17.66 %), 4-terpineol (17.26 %), and β-cedrene (6.94 %). The essential oil displayed fumigant toxicity against booklice, with a median lethal concentration (LC 50 ) of 507.35 μg/L while the isolated constituents, borneol and 4-terpineol, had LC 50 values of 2.20 mg/L and 335.24 μg/L against booklice, respectively. The essential oil also exhibited contact toxicity against L. bostrychophila with an LC 50 value of 210.73 μg/cm 2 . Borneol, caryophyllene oxide, β-cedrene, and 4-terpineol showed acute toxicity against booklice with LC 50 of 98.04, 84.62, 458.79 and 211.35 μg/cm 2 , respectively. Conclusion: The results suggest that the essential oil and its isolates possess potential for cultivation into natural insecticides or fumigants, for control of insects in stored grains. Keywords: Bidens frondosa, Liposcelis bostrychophila , Contact toxicity, Essential oil, Boolice, Stored grains, Natural insecticides, Fumigants

The aim of this study was to evaluate the larvicidal activity of the essential oil of Youngia japonica aerial parts against the larvae of Aedes albopictus and to isolate any active compounds from the oil. Gas chromatography-mass spectrometry (GC-MS) analyses revealed the presence of 31 compounds, with menthol (23.53%), α-asarone (21.54%), 1,8-cineole (5.36%), and caryophyllene (4.45%) as the major constituents. Bioactivity-directed chromatographic separation of the oil led to the isolation of menthol and α-asarone as active compounds. The essential oil of Y. japonica exhibited larvicidal activity against the fourth instar larvae of A. albopictus with an LC50 value of 32.45 μg/mL. α-Asarone and menthol possessed larvicidal activity against the fourth instar larvae of A. albopictus with LC50 values of 24.56 μg/mL and 77.97 μg/mL, respectively. The results indicate that the essential oil of Y. japonica aerial parts and the two constituents can be potential sources of natural larvicides.

Purpose: To determine larvicidal activity of essential oil derived from Clinopodium gracile (Benth.) Matsum. (Labiatae) aerial parts against the larvae of Aedes albopictus Skuse． Methods: Essential oil of C. gracile aerial parts was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The activity of the essential oil was evaluated, using World Health Organization (WHO) procedures, against the fourth larvae of A. albopictus for 24 h and larval mortality recorded at a various essential oil concentrations ranging from 12.5 – 200.0 μg/mL. Results: A total of 34 components of the essential oil of C. gracile were identified. The essential oil has higher content of sesquiterpenoids (70.49 %) than monoterpenoids (12.21 %). The other principal compounds of the essential oil were germacrene D (20.59 %), nootkatone (8.22 %), morillol (7.74 %), βelemene (7.38 %), α-bergamotene (6.08 %), cis-β-farnesene (5.47 %) and caryophyllene (5.17 %). The essential oil exhibited larvicidal activity against A. albopictus with a median lethal concentration (LC50) of 42.56 μg/mL. Conclusion: The findings obtained indicate that the essential oil of C. gracile has potentials for use in the control of A. albopictus larvae and could be useful in the search for new, safer and more effective natural compounds as larvicides.