Structural diversity and defensive properties of norditerpenoid alkaloids.
We have tested the insect antifeedant and toxic activity of 43 norditerpenoid alkaloids on Spodoptera littoralis and Leptinotarsa decemlineata including eserine (physostigmine), anabasine, and atropine. Antifeedant effects of the test compounds were structure- and species-dependent. The most active antifeedants to L. decemlineata were 1,14-diacetylcardiopetaline (9) and 18-hydroxy- 14-O-methylgadesine (33), followed by 8-O-methylconsolarine (12), 14-O-acetyldelectinine (27), karakoline (7), cardiopetaline (8), 18-O-demethylpubescenine (13), 14-O-acetyldeltatsine (18), takaosamine (21), ajadine (24), and 8-O-methylcolumbianine (6) (EC50 < 1 microg/cm2). This insect showed a moderate response to atropine. S. littoralis had the strongest antifeedant response to 24, 18, 14-O-acetyldelcosine (19), and delphatine (29) (EC50 < 3 microg/cm2). None of the model substances affected the feeding behavior of this insect. The most toxic compound to L. decemlineata was aconitine (1), followed by cardiopetalidine (10) (% mortality > 60), 14-deacetylpubescenine (14), 18-O-benzoyl-18-O-demethyl-14-O-deacetylpubescenine (17), 14-O-acetyldelcosine (19), 14-deacetylajadine (25) and methyllycaconitine (30) (% mortality > 45). Orally injected S. littoralis larvae were negatively affected by 1, cardiopetaline (8), 10, 1,14-O-acetylcardiopetalidina (11), 12, 14, 1,18-O-diacetyl-19-oxo-gigactonine (41), olivimine (43), and eserine in varying degrees. Their antifeedant or insecticidal potencies did not parallel their reported nAChR binding activity, but did correlate with the agonist/antagonist insecticidal/antifeedant model proposed for nicotininc insecticides. A few compounds [14, tuguaconitine (38), 14-demethyldelboxine (40), 19, dehydrodelsoline (36), 18-O-demethylpubescenine (13), 41, 9, and delcosine (23)] had selective cytotoxic effects to ward insect-derived Sf9 cells. None were cytotoxic to mammalian CHO cells and none increased Trypanosoma cruzi mortality. The selective cytotoxic effects of some structures indicate that they can act on biological targets other than neuroreceptors.
González-Coloma
Azucena
A
Centro de Ciencias Medioambientales, CSIC, Serrano 115-dpdo, 28006 Madrid, Spain. azu@ccma.csic.es
Reina
Matías
M
Medinaveitia
Alberto
A
Guadaño
Ana
A
Santana
Omar
O
Martínez-Díaz
Rafael
R
Ruiz-Mesía
Lastenia
L
Alva
Allenger
A
Grandez
Maritza
M
Díaz
Rafael
R
Gavín
José A
JA
De la Fuente
Gabriel
G
D000470:Alkaloids / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000633:toxicity; D000691:Anabasine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D016466:CHO Cells; D002460:Cell Line; D001517:Coleoptera / Q000187:drug effects* / Q000502:physiology; D006224:Cricetinae; D004224:Diterpenes / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000633:toxicity; D005247:Feeding Behavior / Q000187:drug effects*; D007300:Insect Control / Q000379:methods; D007306:Insecticides / Q000494:pharmacology* / Q000633:toxicity; D007814:Larva / Q000187:drug effects / Q000502:physiology; D010830:Physostigmine / Q000494:pharmacology; D018411:Spodoptera / Q000187:drug effects* / Q000502:physiology; D013329:Structure-Activity Relationship; D018675:Toxicity Tests
D000470:Alkaloids; D004224:Diterpenes; D007306:Insecticides; D001285:Atropine; D010830:Physostigmine; D000691:Anabasine