title: Insecticidal Properties of a Highly Potent Wax Isolated from Dolichandra cynanchoides Cham.
abstract: Bioassay-guided fractionation of an ethanolic extract of the aerial parts of Dolichandra cynanchoides Cham. (Bignoniaceae) led to the isolation of a natural wax with anti-insect activity against Spodoptera frugiperda (Noctuidae) and Epilachna paenulata (Coleptera). The compound was identified spectroscopically as an ester of a C27 fatty acid and a C25 alcohol, pentacosyl heptacosanoate (1). The effective doses of 1 for 50% feeding inhibition (ED50) of S. frugiperda and E. paenulata were 0.82 and 8.53 µg/cm², respectively, in a choice test, while azadirachtin showed ED50 of 0.10 and 0.59 µg/cm², respectively. In a no-choice test, both insects refused to feed on leaves treated with 1 at doses of 0.1 µg/cm² or greater inhibiting larval growth and dramatically reducing survival. The lethal doses 50 (LD50) of 1 were 0.39 and 0.68 µg/cm² for S. frugiperda and E. paenulata, respectively. These results indicate that 1 has potential for development as botanical insecticides. Similar esters might be obtainable in large quantities as many edible crops produce wax esters that are discarded during food processing. Research on these materials could lead to the detection of similar waxes with insecticidal activity.
authors.affiliation: Unidad Asociada Area Cs. Agr. Ing. Bio. y S.-CONICET-Universidad Católica de Córdoba, Armada Argentina 3555, 5016 Córdoba, Argentina. georgidnapal@hotmail.com.
authors.forename: Georgina
authors.initials: G
authors.lastname: Díaz Napal
authors.affiliation: Unidad Asociada Area Cs. Agr. Ing. Bio. y S.-CONICET-Universidad Católica de Córdoba, Armada Argentina 3555, 5016 Córdoba, Argentina. ceciliacarpinella@ucc.edu.ar.
authors.forename: María C
authors.initials: MC
authors.lastname: Carpinella
authors.affiliation: Unidad Asociada Area Cs. Agr. Ing. Bio. y S.-CONICET-Universidad Católica de Córdoba, Armada Argentina 3555, 5016 Córdoba, Argentina. sarapalacios@ucc.edu.ar.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Palacios
mesh_terms: D000818:Animals; D029402:Bignoniaceae / Q000737:chemistry*; D001517:Coleoptera / Q000187:drug effects; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D015394:Molecular Structure; D035261:Plant Components, Aerial / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018411:Spodoptera / Q000187:drug effects; D014885:Waxes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D007306:Insecticides; D010936:Plant Extracts; D014885:Waxes
keywords: Dolichandra cynanchoides; Epilachna paenulata; Spodoptera frugiperda; antifeedant; wax