A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.I M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43...A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.I M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion ex- change chromatography on DEAE-Sephadex As0. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60~C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 ~tM. The inhibitoi- was found to be susceptible to varying concentrations of reducing agents like DTT and 2- mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth ofPieris brassi- cae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.展开更多
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 ...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.展开更多
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 ...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.展开更多
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 ...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.展开更多
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 insectic...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.展开更多
文摘A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.I M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion ex- change chromatography on DEAE-Sephadex As0. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60~C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 ~tM. The inhibitoi- was found to be susceptible to varying concentrations of reducing agents like DTT and 2- mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth ofPieris brassi- cae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.
文摘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.
基金Project supported by the National Natural Science Foundation of China (Nos. 29672083, 20072043), the Chinese Academy of Sciences, the Ministry of Science and Technology of China (No. G2000077502), and the Shanghai Commission of Science and Technology.
文摘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.
基金the National Natural Science Foundation of China (Grant Nos. 29672083, 20072043), Chinese Academy of Sciences, the State Ministry of Science and Technology (No. G2000077502), Shanghai Committee of Science and Technology and the
文摘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.
基金the National Natural Science Foundation of China (Nos. 29672083, 20072043), the Chinese Academy of Sciences, the State Ministry of Science and Technology (No. 2000077502), the Shanghai Committee of Science and Technology.
文摘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.