Studies on Insecticidal Activities and Active Ingredients of Stephania kwangsiensis Lo.

Insecticidal activities and active ingredients of Stephania kwangsiensis Lo. were studied for the first time. The results showed that all parts of S. kwangsiensis Lo. had contact activity against brown planthoppers, Nilaparvata lugens Stal, and the contact activity of methanol extract from root tubers was the highest, with a LD50 value being 1.5794 lag/female. l-roemerine was isolated from root tubers of S. kwangsiensis Lo. and identified, and it was the main active ingredient. l-roemerine had high contact toxicity to brown planthoppers, with a LD50 value being 0.0443 lag/female. Contact toxicity of l-roemerine to brown planthoppers was 7.48 times that of malathion, the convientional chemical insecticide used for controlling brown planthoppers.l-roemerine also had stomach poison activity against brown planthoppers.

Study on Active Oxygen Quantum Yield,Insecticidal Activities and Stability of Diphenylthiophene

Active oxygen quantum yield, insecticidal activities and stability of diphenylthiophene were studied for the first time. The results showed that maximum diphenylthiophene absorbency variety was 0.438 after irradiation for 280 min and that of α- terthienyl （α-T） was 0.480 after irradiation for 200 min with UV. LCs0 values ofdiphenylthiophene and α-T against 3rd instar larvae ofAedes albopictus were 9.18 × 10^-3 and 9.69× 10^-4 μg mL^-1 when treated for 24 h, respectively. LC50 values of the two chemicals against the 3rd instar larvae of Plutella xylostella were 267.87 and 222.22 μg mL^-1 when treated for 24 h, respectively. The half lives of diphenylthiophene and α-T in methanol were 113.62 and 10.65 h. Difference between quantum yield of diphenylthiophene and α-T was not significant and they all possessed high toxicity to Aedes albopictus and Plutella xylostella, but diphenylthiophene was more stable than α-T. It could be concluded that diphenylthiophene has overcome the deficiency of photoactivated insecticides which degraded quickly in the environment and could not be applied on the field. Diphenylthiophene could kill the insects and accelerate the degradation rate of triazophos. The benefits of diphenylthiophene can be further exploited and applied on the field.

Synthesis and Antifeeding Activity of Acetylene-Containing Tonghaosu Analogs

During our continuous efforts towards the search for environmental benign insect antifeedant, we established a concise method for the synthesis of Tonghaosu, a naturally occurring antifeedant.[1] Herein, we report the synthesis and antifeeding activity of 22 new tonghaosu analogs, which contain varied B ring as well as one or two acetylene functionalities. Preliminary bioassay indicates that two acetylene groups containing tonghaosu analogs have better antifeedant activity against large white butterfly (Pieris brassicae L.) than those with one acetylene group. More interestingly,Z-isomers are much more active than their corresponding E-isomers.……

Synthesis and Insecticidal Structure-Activity Relationships of Novel Tonghaosu Analogs

Twenty-one tonghaosu analogs were synthesized via hydroamination or selective reduction of the endocyclic double bond of the corresponding dienol spiroketals. Structures of all the new compounds were confirmed by ^1H NMR, IR, MS, HREIMS or elemental analysis. Their antifeedant activity against large white butterfly （Pieris brassicae L） and larvicidal activity toward mosquito （Culex quinquefasciatus Say） were examined. Some of them exhibited antifeeding activities comparable to or stronger than tonghaosu Z-1. Based on the activity data, the preliminary structure-activity relationship was also discussed, which might be instructive for finding out lead compounds with better bioactivities in the future.

Synthesis and Bio-activities of Pyrazolyl or Pyridinyl Substituted Tonghaosu Analogs

11 pyrazolyl or pyridinyl substituted tonghaosu analogs were synthesized. Structures of all the new compounds were confirmed by ^1H NMR, IR, MS, HREIMS or elemental analysis. Their antifeedant activity against larvae of large white butterfly （Pieris brassicae L.）, larvicidal activity toward mosquito （Culex quinquefasciatus Say） and growth control activity toward larvae of Spodoptera litura Fab were examined. Some of them exhibited antifeeding activities comparable to or stronger than tonghaosu Z-1. Based on the activity data, the preliminary structure-activity relationship was also discussed, which might be instructive for finding out lead compounds with better bioactivities in the future.

Study on Tonghaosu and Its Analogs:Isolation,Structure Identification and Synthesis of Antifeedant B-ring-homo-tonghaosu

The methanolic extract from a Chinese endemic Chrysanthemum plant, Dendranthema indicum var. aromaticum, was found to show high antifeeding activity against Pieris brassicae L., and by bioassay-guided separation, the ac-tive component, B-ring-homo-tonghaosu, 2-(2',4'-hexadiynylidene)-1,6-dioxaspiro-[4,5]-dec-3-ene (2) was isolated. Its structure was elucidated by comparing its spectroscopic data with those of 2 reported in the literatures. Further-more new convenient total synthesis methods of B-ring-homo-tonghaosu were also developed to confirm its struc-ture and make its further application in crop protection available. In addition, extensive comparison of spectroscopic data showed that the structure of compound 21 reported in literature should be revised to 2.

Synthesis and Biological Activity of Tonghaosu Analogs Containing Phenoxy-phenyl Moiety

A new series of phenoxy-phenyl moieties containing tonghaosu analogs with varied B-ring 9 were synthesized and characterized by spectral studies. Their insect antifeedant activity against Pieris brassicae and insecticidal ac-tivity against Culex quinquefasciatus were investigated. Compound 9e exhibited excellent antifeeding activity.

Bioluminescent nanopaper for rapid screening of toxic substances

Environmental pollution is threatening human health and ecosystems as a result of modern agricultural techniques and industrial progress. A simple nanopaper-based platform coupled with luminescent bacteria Aliivibrio Jischeri （A. Jischeri） as a bio-indicator is presented here, for rapid and sensitive evaluation of contaminant toxicity. When exposed to toxicants, the luminescence inhibition of A. Jischeri-decorated bioluminescent nanopaper （BLN） can be quantified and analyzed to classify the toxicity level of a pollutant. The BLN composite was characterized in terms of morphology and functionality. Given the outstanding biocompatibility of nanocellulose for bacterial proliferation, BLN achieved high sensitivity with a low cost and simplified procedure compared to conventional instruments for laboratory use only. The broad applicability of BLN devices to environmental samples was studied in spiked real matrices （lake and sea water）, and their potential for direct and in situ toxicity screening was demonstrated. The BLN architecture not only survives but also maintains its function during freezing and recycling processes, endowing the BLN system with competitive advantages as a deliverable, ready-to-use device for large-scale manufacturing. The novel luminescent bacteria-immobilized, nanocelullose-based device shows outstanding abilities for toxicity bioassays of hazardous compounds, bringing new possibilities for cheap and efficient environmental monitoring of potential contamination.