Synthesis of Cotinine and Cotinine N-oxide: Evaluation of their Interaction with Nicotine in the Insecticidal Activity

Abstract To evaluate the nature of nicotine interaction with its derivatives, cotinine and N-oxide cotinine were synthesized. In both Lucilia caesar (L. c.) and Calliphora vomitoria (C. v.) flies, nicotine is found more insecticidal than all its derivatives studied. The relative insecticidal activity, determined by the method of Wadley, of nornicotine is ≤ 73%, that of cotinine ≤ 3% and that of cotinine N-oxide ≤ 0.4%. The nature of nicotine interactions with its derivatives was studied by Wadley and Steel and Peckham methods. The two methods indicate that nicotine and nornicotine act at common levels, while nicotine and cotinine act at distinct levels. We concluded that nicotine oxidization is an efficient natural mechanism to nicotine detoxification and that nicotine and cotinine act at distinct molecular levels.