Insect Antifeedant Sesquiterpene Lactones from Schkuhria pinnata: The Direct Obtention of Pure Compounds Using Reverse-phase Preparative Liquid Chromatogrphy

Abstract

The structure of two qennacranolides isolated from the East and West African plant Schkuhria pinnata have been determined by spectroscopic and chemical methods to be 1 (schkuhrin-I) and 3 (schkuhrin-11).These 2, compounds were isolated in pure form directly from the crude aqueous methanol extract of whole plant in gramscale by reverse-phase prep-LC.They exhibit antifeedant activity against the African army worm (Spodoptera exempta) and the Mexican bean beetle, (Epilancha varivestes), antimicrobial activity against some Grampositive bacteria and in vivo cytotoxicity (KB test) at the level of 5.5 vq/ml.Dedicated to Professor Tetsuo Nozoe on the occasion of his seventy-seventh birthday.