Abstract
Insecticidal substances from dried seeds of Mammea siamensis Kost. extracted
with dichloromethane and fractionated by TLC were investigated. The bioassay was
done in laboratory to test for the insecticidal efficiency of those fractions to the egg,
maggot, pupae, and adult of the house fly, Musca domestica (Linn.). The crude extract
of M. siamensis was separated by TLC on a silica plate with toluene: ethylacetate
(80:20) as mobile phase into 8 fractions. The fractions with Rf ≅ 0.61 and Rf ≅ 0.96
tended to express insecticidal affects to the egg of the insect. A total of 61.11% of the
eggs did not develop into maggots. However, there was no significant difference
among these studied fractions. The Rf= 0.96 fractions showed the best average
number of 30 % of pupae which did not develop to adults. The Rf ≅ 0.96 and Rf ≅0.14
showed 51.67 % and 45.00 % mortality in to the adult after 4 h. The Rf= 0.14 and Rf=
0.96 were re-purified by TLC using mobile phase of toluene: ethylacetate (93:7) and
tested for insecticidal efficiency on the adult. The Rf= 0.32 ( from Rf= 0.14) and the
Rf= 0.52 ( from Rf= 0.96) expressed the average number of 90 % and 95 % mortality,
respectively, in 4 h.