Zeitschrift für Naturfosrchung

6 pages, figures, and tables statistics.Natural products have attracted considerable attention as insect antifeedant (Gonzalez-Coloma et al., 2002a, b; Marimoto and Komai, 2006) and phytotoxic (Duke et al., 2000; Hiromasa, 2006) compounds. In recent years, natural quinones and derivatives have been isolated as insecticidal and antifeedant agents (Marimoto et al., 2002; Xu et al., 2003; Wellsow et al., 2006). Furthermore, quinones such as juglone and sorgoleone are well known for their phytotoxic activity (Barbosa et al., 2001; Lim et al., 1996; Lima et al., 2003; Hejl and Kosten, 2004a, b; Topal et al., 2007; Willis, 2000). Hydroxyperezone (1) is a sesquiterpene quinone isolated mainly from Perezia hebeclada roots (Joseph-Nathan et al., 1974) which has been the subject of detailed chemical studies including intramolecular Lewis acid-catalyzed cycloadditions (Joseph-Nathan et al., 1987, 1993) and pioneering 13C NMR studies (Joseph-Nathan et al., 1971) that revealed a tautomeric interconversion of two energetically equivalent forms and 13C NMR quinone ring sustituent chemical shifts (Joseph-Nathan 0939Ð5075/2008/0300Ð0221 $ 06.00 ” 2008 Verlag der Zeitschrift für Naturforschung, Tübingen · http://www.znaturforsch.com ·D et al., 1981; Burguen˜ o-Tapia and Joseph-Nathan, 2000). As part of our program focusing on the study of the chemical and biological properties of natural products and their derivatives (Gonzalez-Coloma et al., 2005; Reina et al., 2006; Burguen˜ o-Tapia et al., 2007), we have been looking into the antifeedant and toxic effects of hydroxyperezone (1) and its derivatives 2Ð9, along with 3-hydroxy- (10) and 6-hydroxythymoquinone (11) against Spodoptera littoralis, Leptinotarsa decemlineata, and Myzus persicae. The phytotoxic activity of compounds 1Ð11 against Lactuca sativa was likewise evaluated.Peer reviewe