Plants belonging to the family Annonaceae have been commonly described in traditional medicine as remedies against head lice, and for their insecticidal properties. Characteristic constituents from a few genera of these plants are the annonaceous acetogenins. Fourteen annonaceous acetogenins have been isolated from our Argentine collection of the seeds of A. cherimolia. We report herein the antifeedant and insecticidal eVects of nine of those acetogenins on Spodoptera frugiperda (J. E. Smith). The acetogenin squamocin, one of the major constituents of the extract, displayed toxic eVects on early larval instars when incorporated to the larval diet at a dose of 50 g per g of diet. The remaining annonaceous acetogenins tested, itrabin, asimicin, neoanonin, cherimolin-1, cherimolin-2, almuñequin, motrilin, and tucumanin produced pupal mortality and adult malformations leading to death, when incorporated to the larval diet at the same dose. The evaluation of indices of food consumption, growth, and food utilization indicated that squamocin was the only tested acetogenin to produce signiWcant decrease in the growth rate and to reduce the eYciency with which larvae converted ingested food into biomass. All the acetogenins produced more than 80% pupal mortality with no dependence on the position of the THF rings or the number and location of the OH groups.

Two new norditerpenoids, 4beta-hydroxy-19-normanoyl oxide (1) and 4alpha-hydroxy-18-normanoyl oxide (2), the new 18-O-alpha-l-arabinopyranosylmanoyl oxide (3a), and the known diterpenoids jhanol (4) and 18-hydroxy-13-epi-manoyl oxide (5) were isolated, together with other common plant constituents from an Argentine collection of Grindelia scorzonerifolia. The structures of the new compounds were established by extensive 1D and 2D NMR techniques and chemical transformations. Structural features of compounds 2 and 4 were verified by X-ray crystallographic analyses. The insecticidal effect of compound 3a was evaluated against the polyphagous pest Spodoptera frugiperda. Pupal and adult malformations leading to death occurred when 3a was incorporated in a larval diet at a concentration of 100 ppm.

Several species of the large family of tropical plants Annonaceae have been intensely investigated over the last 20 years, mainly because of the discovery of annonaceous acetogenins. These compounds are powerful cytotoxics, with potential applications as insecticides, antiparasitics, acaricides, fungicides, and antitumor drugs. Annona montana Macfad. (Annonaceae) grows in Santa Cruz de la Sierra, Bolivia, where an infusion of leaves is used for the treatment of lice, influenza, and insomnia. The major acetogenins from a Bolivian collection of A. montana, annonacin (1), cis-annonacin-10-one (2), densicomacin-1 (3), gigantetronenin (4), murihexocin-B (5), and tucupentol (6), were evaluated for their antifeedant and toxic effects on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), a serious pest affecting corn crops in Argentina. All the acetogenins produced 100% mortality during the larval or pupal stages at 100 lg of treatment per gram of diet. In addition, compounds 2, 3, and 4 deterred more than 80% feeding at the same dose. Relative toxicity values of LD 50 for the strongest larvicidal compounds 1, 2, and 4 were determined, indicating that the three compounds are effective natural insecticides. This is the first report on the antifeedant and toxic effects produced by the particular type of acetogenins, the mono-THF acetogenins, on the lepidopteran S. frugiperda. No correlation was detected between the toxicity of the mentioned compounds to larvae and the known capacity of the acetogenins 1, 2, and 4 to inhibit the NADH oxidase, indicating that the inhibition of the mitochondrial complex I is not the only cause for larval mortality of S. frugiperda.

From an Argentine collection of the tropical tree Rollinia emarginata (Annonaceae), vomifoliol, dehydrovomifoliol, blumenol C, loliolide, 7-epiloliolide, vanillin, dihydroactinolide, as well as other common plant constituents were obtained, and identified by their NMR and MS features compared with authentic samples. Antifeedant and toxic actions were exerted to the polyphagous moth Spodoptera frugiperda by the ethanol extract of the plant, at 250 ppm in the larval diet. Additionally, in greenhouse studies, a 200 ppm aqueous solution of the extract produced a post-emergency herbicidal effect on the annual weed common lambsquarter (Chenopodium album).