Chemistry and potential of parthenin and its derivatives as stored grain protectants

Parthenin was isolated from shade dried and powdered leaves of Parthenium hysterophorus, a common weed. Extraction was done using Soxhlet extraction method followed by column chromatography. Different derivatives of parthenin were prepared by reaction with diazomethane, sodium borohydride, methanol and diethanolamine. The structures of all the compounds were elucidated by spectroscopic techniques. All the compounds along with parthenin were subjected to biological evaluation against adults of Tribolium castaneum by releasing them in wheat grains spiked with various concentrations of test compounds in the range of. 0.5 - 10.0 mg g⁻¹ of wheat. The corrected percent mortality was calculated using Abbott's formula. All the compounds exhibited complete mortality at the spiking level of 10.0 mg g⁻¹. Reduction product was found to be most potent followed by parthenin, diethanolamine adduct, methanol adduct and diazomethane adduct. The structure activity relationship of parthenin and its derivatives was established.