Towards the optimization of botanical insecticides research: Aedes aegypti larvicidal natural products in French Guiana

Michaël Falkowski (1) , Arnaud Jahn-Oyac (1) , Guillaume Odonne (2) , Claudiane Flora (1) , Yannick Estevez (1) , Seindé Touré (1) , Isabelle Boulogne (3, 4, 1) , Jean-Charles Robinson (5) , Didier Béreau (5) , Philippe Petit (4) , Didier Azam (6) , Maïra Coke (6) , Jean Issaly (7) , Pascal Gaborit (7) , Didier Stien (8) , Véronique Eparvier (9) , Isabelle Dusfour (7, 10) , Emeline S Houël (1)

1 UMR ECOFOG - Ecologie des forêts de Guyane
2 LEEISA - Laboratoire Ecologie, Evolution, Interactions des Systèmes amazoniens
3 Glyco-MEV - Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale
4 Université des Antilles (Pôle Guadeloupe)
5 UMR Qualisud - Démarche intégrée pour l'obtention d'aliments de qualité
6 UEEA - Unité d'Ecologie et Ecotoxicologie Aquatiques
7 Institut Pasteur de la Guyane
8 LBBM - Laboratoire de Biodiversité et Biotechnologies Microbiennes
9 ICSN - Institut de Chimie des Substances Naturelles
10 INRS-IAF - Institut Armand Frappier

Natural products have proven to be an immeasurable source of bioactive compounds. The exceptional biodiversity encountered in Amazonia, alongside a rich entomofauna and frequent interactions with various herbivores is the crucible of a promising chemodiversity. This prompted us to search for novel botanical insecticides in French Guiana. As this French overseas department faces severe issues linked to insects, notably the strong incidence of vector-borne infectious diseases, we decided to focus our research on products able to control the mosquito Aedes aegypti. We tested 452 extracts obtained from 85 species originating from 36 botanical families and collected in contrasted environments against an Ae. aegypti laboratory strain susceptible to all insecticides, and a natural population resistant to both pyrethroid and organophosphate insecticides collected in Cayenne for the most active of them. Eight species (Maytenus oblongata Reissek, Celastraceae; Costus erythrothyrsus Loes., Costaceae; Humiria balsamifera Aubl., Humiriaceae; Sextonia rubra (Mez) van der Werff, Lauraceae; Piper hispidum Sw., Piperaceae; Laetia procera (Poepp.) Eichl., Salicaceae; Matayba arborescens (Aubl.) Radlk., Sapindaceae; and Cupania scrobitulata Rich., Sapindaceae) led to extracts exhibiting more than 50% larval mortality after 48 h of exposition at 100 µg/mL against the natural population and were considered active. Selectivity and phytochemistry of these extracts were therefore investigated and discussed, and some active compounds highlighted. Multivariate analysis highlighted that solvents, plant tissues, plant family and location had a significant effect on mortality while light, available resources and vegetation type did not. Through this case study we highlighted that plant defensive chemistry mechanisms are crucial while searching for novel insecticidal products.

Keywords: Amazonian chemodiversity; Chemical defense; Culicidae; Mosquito larvicides; Quasi-Poisson generalized linear model; Screening optimization

Domains: Chemical Sciences; Chemical Sciences; Organic chemistry; Life Sciences [q-bio]

Michaël Falkowski, Arnaud Jahn-Oyac, Guillaume Odonne, Claudiane Flora, Yannick Estevez, et al.. Towards the optimization of botanical insecticides research: Aedes aegypti larvicidal natural products in French Guiana. Acta Tropica, 2020, 201, pp.105179. ⟨10.1016/j.actatropica.2019.105179⟩. ⟨hal-02302317⟩