Relationships between structure and molting hormonal activity of tebufenozide, methoxyfenozide, and their analogs in cultured integument system of Chilo suppressalis Walker.
The molting hormonal activity of methoxyfenozide (RH-2485), tebufenozide (RH-5992), five analogs with various alkyl groups, and 18 acyl analogs was measured by using cultured integument of rice stem borers, Chilo suppressalis Walker. The hormonal activity of methoxyfenozide was remarkably high (EC(50) = 1.1 x 10(-9) M), being equivalent to that of tebufenozide (RH-5992). The hormonal activity of several tebufenozide analogs with varying alkyl groups such as CH(3), n-C(3)H(7), i-C(3)H(7), n-C(4)H(9) and n-C(5)H(11) at the para-position of the benzene ring furthest from the tert-butyl group was lower than that of tebufenozide (alkyl group is C(2)H(5)). The activity decreased to varying degrees as a result of replacement of the 3,5-dimethylphenyl moiety of tebufenozide with either a phenyl, naphthyl, or cyclohexyl group. Both 1- and 2-naphthyl derivatives were very active (EC(50) = 4.3 x 10(-8) M and 3.2 x 10(-8) M, respectively) without any significant difference between them. The activity of the 1-cyclohexenyl analog (EC(50) = 1.0 x 10(-7) M) was about 40x that of the corresponding 3-cyclohexenyl analog (EC(50) = 4.4 x 10(-6) M), but 1/100 that of tebufenozide. The activity varied parabolically with respect to the molecular hydrophobicity, and decreased with longer acyl moieties.
Nakagawa
Y
Y
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan. naka@kais.kyoto-u.ac.jp
Hattori
K
K
Minakuchi
C
C
Kugimiya
S
S
Ueno
T
T
D000818:Animals; D046508:Culture Techniques / Q000379:methods; D006834:Hydrazines / Q000737:chemistry / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000187:drug effects* / Q000254:growth & development; D013329:Structure-Activity Relationship
D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; C406712:methoxyfenozide; C082026:tebufenozide