Structure-antifeedant activity relationship of clerodane diterpenoids. Comparative study with withanolides and azadirachtin.
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 alpha,beta-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.
Enriz
R D
RD
Departamento de Química, Cátedra de Entomología, and Laboratorio de Alimentos, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina. denriz@unsl.edu.ar
Baldoni
H A
HA
Zamora
M A
MA
Jáuregui
E A
EA
Sosa
M E
ME
Tonn
C E
CE
Luco
J M
JM
Gordaliza
M
M
D000818:Animals; D004224:Diterpenes / Q000737:chemistry / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects; D007306:Insecticides / Q000494:pharmacology*; D036701:Limonins; D008958:Models, Molecular; D008968:Molecular Conformation; D010944:Plants / Q000737:chemistry; D013329:Structure-Activity Relationship; D013712:Tenebrio; D014315:Triterpenes / Q000737:chemistry / Q000494:pharmacology*
D004224:Diterpenes; D007306:Insecticides; D036701:Limonins; D014315:Triterpenes; C010329:azadirachtin