Antifeedant Activities of Secondary Metabolites from Hyssopus cuspidatus Against Plutella xylostella

A new sesquiterpene hyssopusin A ( 1 ), together with four known compounds 2–5 , was isolated from Hyssopus cuspidatus . The structure of hyssopusin A ( 1 ) was elucidated by physical and spectroscopic data analysis, including 1D NMR, 2D NMR, and HR-ESI-MS. Compounds 1–4 showed antifeedant effects against the third instar larvae of Plutella xylostella (Lepidoptera: Plutellidae) in a concentration-dependent manner with 50% antifeedant concentrations (AFC 50 ) of 32.17, 38.33, 25.47, and 36.22 μg/cm 2 , respectively.