Eudesmanes from Pluchea sagittalis. Their antifeedant activity on Spodoptera frugiperda

NANCY VERA; ROSANA MISICO; MANUEL GONZÁLEZ SIERRA; YOSHINORI ASAKAWA; ALICIA BARDÓN*

PHYTOCHEMISTRY

Elsevier

Lugar: Amsterdam; Año: 2008 vol. 69 p. 1689 - 1694

0031-9422

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Eudesmane-type sesquiterpenoids 3a-(2,3-epoxy-2-methylbutyryloxy)-4a-formoxy-11-hydroxy-6,7-dehydroeudesman-8-one (1) and 3a-(2,3-epoxy-2-methylbutyryloxy)-4a,7a,11-trihydroxyeudesman-8-one (2), together with 10 known structurally related eudesmanes were isolated from the CHCl3 extract of aerial parts of Pluchea sagittalis (Lamarck) Cabrera. Their structures were deduced by extensive application of 1 and 2D NMR spectroscopic techniques and high and low resolution CIMS. X-Ray crystallographic analysis of the known compound 3a -(2,3-epoxy-2-methylbutyryloxy)-4a-formoxycuauthemone (9) is reported here for the first time, and confirms the structural features for the series of the reported eudesmanes. All eudesmanes were tested for their antifeedant activity by incorporating them to an artificial diet of larvae of the polyphagous insect Spodoptera frugiperda at a concentration of 100 ppm. Our results, from feeding choice tests, indicated that most of the compounds deter larval feeding at the cited concentration.