Physical and Chemical Characterization of Melia azedarach L. Fruit and Leaf for Use as Botanical Insecticide

A study was undertaken of the physical and chemical characteristics and insecticide properties of melia (Melia azedarach L.) (Meliaceae) fruit and leaves; melia has been introduced in Chile for ornamental purposes. The physical and chemical properties were evaluated in two stages of fruit and leaf maturity, i.e., green /mature, and mature/juvenile, respectively. Laboratory bioassays were carried out on Drosophila melanogaster Meigen (Diptera: Drosophilidae) as an insect model. The diameter of M. azedarach fruit was in the lower limit in relation to other studies. The flour obtained from green fruit had an average dry weight inferior to that of mature fruit. The average dry leaf weights were similar in both juvenile and mature states. The green fruits had 50% initial humidity, similar to juvenile (60%) and mature (57%) leaves, but greater than the mature fruits (44%). The chemical analysis of the fruit maturity stages determined a slight increase in crude fiber content as maturity increased. There was a decrease in the lipid content of leaves close to 60% at maturity. Furthermore, an analysis of polyphenols was made using HPLC-DAD (High Performance Liquid Chromatography-Diode Array Detector), and 14 compounds were identified as causes of the insecticidal effect of the M. azedarach fruit, of which three would correspond to flavonoids: one catechin and two kaempherols. Finally, the aqueous fruit and leaf extracts of M. azedarach were effective insecticides on D. melanogaster, reaching 90% mortality (125 000 mg kg-1) with juvenile leaves and 73.3% (10 700 mg kg-1) with green fruit. Se estudiaron las características físicas, químicas y las propiedades insecticidas del fruto y hojas de melia (Melia azedarach L.) (Meliaceae), árbol introducido con fines ornamentales en Chile. Se evaluaron las propiedades físicas y químicas de dos estados de madurez del fruto, verde y maduro, y de las hojas, juveniles y maduras. Las propiedades insecticidas se evaluaron mediante bioensayos de laboratorio sobre Drosophila melanogaster Meigen (Diptera: Drosophilidae), como insecto modelo. El diámetro del fruto de M. azedarach se situó en el límite inferior con referencia a otros estudios. La harina obtenida del fruto verde tuvo un peso seco promedio inferior al maduro. Las hojas tuvieron pesos secos promedio similares, tanto en el estado juvenil como en el maduro. Los frutos verdes tuvieron un contenido de humedad de 50%, similar a las hojas juveniles (60%) y maduras (57%), pero may