Inhibition of Na~+,K~+-ATPase in Housefly (Musca domestica L.) by Terpinen-4-ol and Its Ester Deriva

To reveal the insecticidal mechanism of terpinen-4-ol,the activity of Na+,K+-ATPase in insects tested were determined in vivo and in vitro.The results showed that terpinen-4-ol and its ester derivatives had strong contact activity to housefly and the contact toxicities of its derivatives except Z3 were all superior or equivalent to terpinen-4-ol.All the 7 compounds had strong inhibition towards activity of Na+,K+-ATPase.With poisoning symptom exacerbating,the inhibition rates were gradually increased.In vitro,the IC50 of terpinen-4-ol,Z1,Z2,Z4,Z5,and Z6 was 155.89,197.98,96.02,121.36,124.85,and 153.74 μg mL-1,respectively.There was well correlation between the LD50 of terpinen-4-ol derivatives to housefly and the IC50 of terpinen-4-ol derivatives to Na+,K+-ATPase in housefly.In conclusion,Na+,K+-ATPase was likely the target of terpinen-4-ol against insects.