TOXICITY OF ALKALOID FRACTIONS FROM Psychotria spp. (RUBIACEAE) AGAINST Atta sexdens Forel, 1908 (HYMENOPTERA: FORMICIDAE)

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Dejane Santos Alves Pilar Canela Garcia Fernandez http://orcid.org/0000-0002-1673-7889 Alejandro Martin Martin http://orcid.org/0000-0003-2957-5548 Flor Budia http://orcid.org/0000-0002-9614-2219 Geraldo Andrade Carvalho http://orcid.org/0000-0002-8379-8008 Ronald Zanetti http://orcid.org/0000-0001-5698-1838 Denilson Ferreira de Oliveira http://orcid.org/0000-0001-9326-8716

Abstract

Leaf-cutting ants are the main pests in forest plantations. The most commonly used chemical control for the ants is toxic bait. However, the active ingredients in these baits have been restricted by forest certification organizations, justifying the search for new active compounds to control these insects. Thus, this work aimed to evaluate the formicidal activity of alkaloid fractions from the roots, stems, branches and leaves of Psychotria hastisepala and Psychotria leiocarpa against Atta sexdens. The alkaloid fractions were obtained from the crude methanolic extracts of P. hastisepala and P. leiocarpa by the acid-base extraction method employing liquid-liquid partitions. The fractions, previously solubilized in propanone, were applied topically to the pronotum of worker ants. Bioassays were conducted in a completely randomized design, with six replicates of each treatment and 10 ants per replicate. Insect survival was assessed daily for 21 days. The median lethal time was estimated by Weibull models. The root fractions from P. hastisepala presented the highest toxicity, followed by those from the branches, stems and leaves. Among fractions from P. hastisepala roots, the most toxic were a fraction that apparently is rich in lipophilic compounds and nonbasic alkaloids and a fraction that is likely rich in quaternary benzophenanthridine alkaloids, protopine alkaloids and tertiary bases. Psychotria leiocarpa fractions were not toxic to this insect. Psychotria hastisepala is potentially useful for the development of new products for A. sexdens control.

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How to Cite
ALVES, Dejane Santos et al. TOXICITY OF ALKALOID FRACTIONS FROM Psychotria spp. (RUBIACEAE) AGAINST Atta sexdens Forel, 1908 (HYMENOPTERA: FORMICIDAE). CERNE, [S.l.], v. 25, n. 2, p. 255-262, july 2019. ISSN 2317-6342. Available at: <http://cerne.ufla.br/site/index.php/CERNE/article/view/2112>. Date accessed: 10 dec. 2019.
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