NOVEL ANTIFEEDANT AND INSECTICIDAL COMPOUNDS FROM AVOCADO IDIOBLAST CELL OIL

Several insecticidal compounds have been identified by bioassay-driven fractionation of avocado, Persea americana Mill, idioblast cell oil. A flash chromatography fraction of the oil showed substantial toxicity to early instars of the generalist insect herbivore, Spodoptera exigu a (Hubner) (100% mortality after seven days). Following further fracti onation, five biologically active compounds, 2-(pentadecyl)furan, 2-(h eptadecyl)furan, 2-(1E-penta-decenyl)furan, 2-(8Z,11Z-heptadecadienyl) furan, and the triglyceride triolein, were identified. Several minor c omponents were also tentatively identified, including 2-(1Z-pentadecen yl)furan, 2-(1E-heptadecenyl)furan, and 2-(1E,8Z,11Z-heptadecatrienyl) furan. Several 2-alkylfurans of this type have been reported previousl y from avocado (Persea spp.) and have received the common name of avoc adofurans. The major compounds were tested individually for toxic and growth inhibitory effects. Individually, the compounds had low to mode rate toxicity. Of these, 2-(pentadecyl)furan had the greatest effects, with an LC50 value of 1031 mu g/g. At concentrations of 600 mu g/g or higher in diets, larval growth was inhibited by >70% compared to cont rols. The analogous 2-(heptadecyl)furan had an LC50 value of 1206 mu g /g, and also significantly reduced larval growth (>75% versus controls ) at concentrations of > 600 mu g/g. The unsaturated analogs 2-(1E-pen tadecenyl)furan and 2-(8Z, 11Z-heptadecadienyl)furan were less toxic. Triolein was only weakly toxic, with an LC50 value of 10,364 mu g/g di et. Larval growth was inhibited only at concentrations of 7000 mu g/g or higher. The potential of avocadofurans in insect control is discuss ed.