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PHYSICAL
AND CHEMICAL CHARACTERIZATION OF Melia azedarach L. FRUIT
AND LEAF FOR USE AS BOTANICAL INSECTICIDE
Italo Chiffelle G.1,
Amanda Huerta F.*,
and Diego Lizana R.2
ABSTRACT
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.
Key words: Chinaberry
tree, Meliaceae, phenolic compounds.
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