The Effects of Anabasine and the Alkaloid Extract of Nicotiana glauca on Lepidopterous Larvae

For several decades, Nicotiana glauca has been known for its content of the pyridine alkaloid, anabasine. The toxicological effects of this metabolite have been extensively studied, as opposed to its potential insecticidal activity. The anabasine content of leaves of N. glauca, collected from Malta, was 0.258 ± 0.0042% as determined by High Performance Liquid Chromatography. In the Pieris rapae larval bioassay, the median effective concentrations of anabasine and the alkaloid extract were 0.572 and 1.202 mg per larva, respectively. The presence of other interfering metabolites may have resulted in this elevated EC50 for the crude extract. Anabasine is quoted to be a very toxic alkaloid not solely to insects, but also to other animals, and its use in minute concentrations in insect traps may well prove it to be an effective natural insecticide.