Wang Mingan

Insecticidal sesquiterpene pyridine alkaloids from Euonymus species

Three insecticidal sesquiterpene pyridine alkaloids with a beta-dihydroagarofuran sesquiterpene skeleton, euoverrine A (1), B (2), and euophelline (3), and a known compound, euojaponine C (4), were isolated from the root bark of Euonymus verrucosides, E. fortunei and E. phellomana by bioassay-guided fractionation. Their chemical structures were elucidated mainly by analyses NMR and MS spectral data.

Insecticidal sesquiterpene polyol esters from Celastrus angulatus

Three insecticidal sesquiterpene polyol esters were isolated from the root bark of Celastrus angulatus by bioassay-guided fractionation. Their chemical structures were elucidated as 1 alpha,2 alpha-diacetoxy-8 beta-isobutanoyloxy- 9 alpha-benzoyloxy-13-(alpha-methyl)butanoyloxy-4 beta, 6 beta-dihydroxy-beta-dihydroagarofuran (1), 1 alpha,2 alpha-diacetoxy-8 beta-(beta- furancarbonyloxy)-9 alpha-benzoyloxy-13-isobutanoyloxy-4 beta, 6 beta-dihydroxy-beta-dihydroagarofuran (2) and 1 alpha, 6 beta, 8 alpha,13-tetraacetoxy-9 alpha-benzoyloxy-2 alpha-hydroxy-beta-dihydroagarofuran (3) mainly by analyses NMR and MS spectral data.

Four novel insecticidal sesquiterpene esters from Celastrus angulatus

Four new insecticidal sesquiterpene polyol esters with a β-dihydroagarofuran sesquiterpene skeleton, celangulatin C (1), celangulatin D (2), celangulatin E (3), and celangulatin F (4), and five known compounds 5–9 were isolated from the low-polar toluene extracts of the root bark of Celastrus angulatus by bioassay-guided fractionation. Their chemical structures were elucidated mainly by analyses of MS and NMR spectral data. Celangulatin C, E and F showed LD50 against Mythimna separata were 280.4, 1656.4 and 210.5 µg mL−1, respectively.

Three new insecticidal sesquiterpene pyridine alkaloids from Celastrus angulatus

Three new sesquiterpene pyridine alkaloids with a β-dihydroagarofuran sesquiterpene skeleton, celangulatin G(1), H(2) and I(3), and one known alkaloid 4 were isolated from the middle-polar extracts of the root bark of Celastrus angulatus by bioassay-guided separation. Their chemical structures were elucidated mainly by the analyses of the MS and NMR spectral data. Celangulatin G(1), H(2), I(3) and 4 showed KD50 against Mythimna separata were 849.61, 80.24, 96.29 and 50.98 µg g−1, respectively.

Two new insecticidal sesquiterpene polyol esters from Celastrus angulatus

Two new insecticidal sesquiterpene polyol esters with a β-dihydroagarofuran sesquiterpene skeleton, celangulatin A (1), B (2), and two known compounds, celangulin IV (3) and V (4), were isolated from the leaves of Celastrus angulatus by bioassay-guided fractionation. Their chemical structures were elucidated mainly by analyses of the NMR and MS spectral data. Their insecticidal activities against Mythimna separate were demonstrated with the KD50 value of 68.5 and 215.8 μg g−1, respectively.

Synthesis, photostability and bioactivity of 2,3-cyclopropanated abscisic acid.

The plant hormone abscisic acid (ABA) plays a central role in the regulation of plant development and adaptation to environmental stress. The isomerization of ABA to the biologically inactive 2E-isomer by light considerably limits its applications in agricultural fields. To overcome this shortcoming, an ABA analogue, cis-2,3-cyclopropanated ABA, was synthesized, and its photostability and biological activities were investigated. This compound showed high photostability under UV light exposure, which was 4-fold higher than that of (±)-ABA. cis-2,3-cyclopropanated ABA exhibited high ABA-like activity, including the ability to effectively inhibit seed germination, seedling growth and stomatal movements of Arabidopsis. In some cases, its bioactivity approaches that of (±)-ABA. trans-2,3-cyclopropanated abscisic acid was also prepared, an isomer that was more photostable but which showed weak ABA-like activity.

A new aromatic triterpene from Euonymus japonicus

A new aromatic triterpene was isolated from the root bark EtOAc extract of Euonymus japonicus Thunb, and its chemical structure was elucidated mainly by analysis of MS and NMR spectra.A new aromatic triterpene was isolated from the root bark EtOAc extract of Euonymus japonicus Thunb, and its chemical structure was elucidated mainly by analysis of MS and NMR spectra.