Structure-antifeedant activity relationship of clerodane diterpenoids. Comparative study with withanolides and azadirachtin

ENRIZ, RICARDO D.; BALDONI, HÉCTOR A.; ZAMORA, MIGUEL A.; JÁUREGUI, ESTEBAN A.; SOSA, MARTA E.; TONN, CARLOS E.; LUCO, JUAN M.; GORDALIZA, MARINA

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

AMER CHEMICAL SOC

Año: 2000 vol. 48 p. 1384 - 1392

0021-8561

A structure-antifeedant activity relationship (SAR) study of clerodane diterpenoids was carried out. Attention was focused on the feeding-deterrent activities exhibited toward Tenebrio molitor by clerodane diterpenoids and withanolides. Azadirachtin was chosen as a reference compound. SAR studies on the clerodane compounds indicate that the stereoelectronic factors are more important than the hydrophobic aspects as determinants of antifeedant activity. A furan ring in the side chain and a carbonyl α,β-unsaturated (or spiro-epoxide) group appear to be indispensable for the biological response. A conformational study indicate that the optimum interatomic distance between these moieties is a range between 9.5 and 10.5 A. In addition, a similar stereoelectronic response was found among withanolides and azadirachtin. On the basis of these results it is reasonable to imagine a closely related chemical mechanism for these compounds.