Sesquiterpenes from Onopordum illyricum and their antifeedant activity

Abstract

Phytochemical investigation of the acetone extract of the aerial parts of Onopordum illyricum L. afforded five known sesquiterpenoids: compounds 3 and 4 already isolated from O. illirycum, and 8α-[4′- hydroxymethacryloyloxy]-sonchucarpolide (1), 8α-[4′- hydroxymethacryloyloxy]-4-epi-sonchucarpolide (2) and 8-(4′- hydroxymethacryloyl)-dehydromelitensin (5), not previously detected in this species. Compounds 4 and 5 showed moderate antifeedant activity against larvae of Spodoptera littoralis.