الفهرس 
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Abstract
The present investigation was conducted to study the toxic action of
the extracts of different parts of Melia azedarach plant on Culex pipiens
larvae which infesting ahumanbing. In this respect, different parts of
Melia azedarach plant extracted with two methods of extraction, the first
were extracted successively with 6 solvent systems and the second was
extracted with one solvent only.
Summarized results show the following:
PART I
Studies on the toxic action of Melia azedarach plant extracts
The different parts of Melia azedarach plant extracted namely:
Green seeds, yellow seeds, yellow leaves with stems, green leaves
and green leaves with stems were extracted with two methods of extraction,
the first method namely successive extraction which each part of Melia
azedarach plant extracted successively with petroleum ether, diethyl ether,
chloroform, acetone, ethyl alcohol and H2O & the second method of
extraction namely isolation of compound which each part of Melia
azedarach plant extracted with petroleum ether only.
The 35 extracts resulted from extraction of different parts of Melia
azedarach plant by two methods of extraction were tested as insecticide
against Culex pipiens larvae.
Conventional insecticides (Sumithrin, Malathion) and IGR (Altosid)
was tested against Culex pipiens larvae.
Also, the joint action of mixtures of these extracts with conventional
insecticides and IGR were tested against Culex pipiens larvae.
Chemical analysis for separation and identification of the
biologically active compound of the most toxic extract tested against Culex
pipiens larvae were also achieved.
A. Insecticidal activity to extracts of Melia azedarach plant:
1-Toxicity of successive extraction:
According to the Lc50 values after 24&48 hrs (exposure periods).
The toxicity and insecticidal activity of each part of different parts of Melia
azedarach plant, extracted by different solvent tested against Culex pipiens
larvae differ according to the solvent used in its successive extraction. The
summarized results show the following:
Green seeds records highest toxicity and insecticidal activity on
Culex pipiens larvae when extracted with petroleum ether at 13 ppm (after
24 hrs) and at 4.2 ppm (after 48 hrs).
Yellow seeds records highest toxicity and insecticidal activity on
Culex pipiens larvae when extracted with H2o at 35 ppm (after 24 hrs) and
at 29 ppm (after 48 hrs).
Yellow leaves with stems records highest toxicity and insecticidal
activity on Culex pipiens larvae when extracted with ethyl alcohol at 25
ppm (after 24 hrs) and at 20 ppm (after 48 hrs).
Green leaves records highest toxicity and insecticidal activity on
Culex pipiens larvae when extracted with ethyl alcohol at 4.1 ppm (after 24
hrs) and at 3.4 ppm (after 48 hrs).
Green leaves with stems records highest toxicity and insecticidal
activity on Culex pipiens larvae when extracted with chloroform at 3.6 ppm
(after 24 hrs) and at1.3 ppm (after 48 hrs).
Among 30 extracts resulted from the successive extraction using
different solvent to each part of different parts of Melia azedarach plant,
there’s one solvent to each part when extracted with it giving highest
toxicity and insecticidal activity when tested against Culex pipiens larvae.
So, the highest toxicity and insecticidal activity to each part of different
parts of Melia azedarach plant with its best solvent used through its
successive extraction could be arranged according to the last summarized
results as following:
Green leaves with stems when extracted with chloroform > green
leaves when extracted with ethyl alcohol > green seeds when extracted with
petroleum ether > yellow leaves with stems when extracted with ethyl
alcohol > yellow seeds when extracted with H2o.
2- Toxicity of Isolation of compound extraction:
According to the Lc50 values after 24 & 48 hrs (exposure-periods).
The toxicity and insecticidal activity of each part of different parts of Melia
azedarach plant, extracted by one solvent (petroleum ether) tested against
Culex pipiens larvae. The summarized results show the following:
Green leaves with stems extract records highest toxicity and
insecticidal activity on Culex pipiens larvae when used as insecticide at
0.52 ppm (after 24 hrs) and at 0.42 ppm (after 48 hrs).
Among five extracts resulted from isolation of compound extraction
using one solvent to each part of different parts of Melia azedarach plant.
The toxicity and insecticidal activity to each part of different parts of Melia
azedarach plant when tested against Culex pipiens larvae arranged
according to the last summarized results as following:
Green leaves with stems extract > green leaves extract > green seeds
extract >yellow leaves with stems extract > yellow seeds extract.
The toxicity and insecticidal activity to the extracts resulting from
second method of extraction are more than the extracts resulting from first
method of extraction according to Lc50 and Lc90 values after 24 & 48 hrs.
Among 35 extracts resulted from using two methods of extraction to
each part of different parts of Melia azedarach plant. Green leaves with
stems extract records highest toxicity and insecticidal activity in both two
methods of extraction used when tested against Culex pipiens larvae.
B. Insecticidal activity to conventional insecticides and IGR:
According to the Lc50 values after 24 & 48 hrs (exposure-periods).
The toxicity and insecticidal activity to conventional insecticides
(Sumithrin & Malathion) and IGR (Altosid) tested against Culex pipiens
larvae. The summarized results show the following:
Sumithrin records highest toxicity and insecticidal activity on Culex
pipiens larvae when used as insecticide at 50 ppm (after 24 hrs) and at 30
ppm (after 48 hrs).
The toxicity and insecticidal activity from using conventional
insecticides and IGR when tested against Culex pipiens larvae arranged
according to the last summarized results as following:
Sumithrin > Malathion > IGR (altosid).
The toxicity and insecticidal activity to the extracts resulting from
second method of extraction are more than the conventional insecticides
and IGR when tested against Cx. Pipiens larvae.
C. Joint action of mixtures of Melia azedarach plant extracts with
conventional insecticides and IGR:
According to the Lc50 values after 24 & 48 hrs (exposure-periods).
The toxicity and insecticidal activity to the joint action of mixture of each
part of different parts of Melia azedarach plant, extracted by second
method of extraction with conventional insecticides (Sumithrin &
Malathion) andIGR (Altosid) tested against Culex pipiens larvae. The
Summarized results show the following:
Green seeds extract records highest toxicity and insecticidal activity
on Culex pipiens larvae when mixed with sumithrin at 0.8 ppm (after 24
hrs) and at 0.48 ppm (after 48 hrs).
Yellow seeds extract records highest toxicity and insecticidal activity
on Culex pipiens larvae when mixed with sumithrin at 1.9 ppm (after 24
hrs) and at 1.1 ppm (after 48 hrs).
Yellow leaves with stems extract records highest toxicity and
insecticidal activity on Culex pipiens larvae when mixed with sumithrin at
0.9 ppm (after 24 hrs) and at 0.7 ppm (after 48 hrs).
Green leaves extract records highest toxicity and insecticidal activity
on Culex pipiens larvae when mixed with sumithrin at 0.74 ppm (after 24
hrs) and at 0.45 ppm (after 48 hrs).
Green leaves with stems extract records highest toxicity and
insecticidal activity on Culex pipiens larvae when mixed with sumithrin at
0.36 ppm (after 24hrs) and at 0.19 ppm (after 48 hrs).
Among 15 mixture resulted. The toxicity and insecticidal activity of
the joint action of mixture of each part of different parts of Melia
azedarach plant extracted by second method of extraction with
conventional insecticides (sumithrin & malathion) and IGR (Altosid) tested
against Culex pipiens larvae arranged according to the last Summarized
results as following:
Mixture of green leaves with stems extract and Sumithrin > mixture
of green leaves extract and Sumithrin > mixture of green seeds extract and
Sumithrin > mixture of yellow leaves with stems extract and Sumithrin >
mixture of yellow seeds extract and Sumithrin.
Addition ofinsecticides and IGR making rise the promotion of the
toxicity and insecticidal activity of Melia azedarach plant extracts when
tested against Culex pipiens larvae.
Part II
Separation and Identification of the biologically active
compound in active extract of Melia azedarach plant extracts
Phytochemical analysis carried out on the most active extracts which
resulted from using second method of extraction on different parts of Melia
azedarach plant indicates the presence of terpenes, condensed tannins and
alkaloids compounds and by applying it on green leaves with stems extract,
extracted by second method of extraction which proving highest toxicity
and insecticidal activity among 35 extracts resulted from two methods of
extraction indicates the presence of terpenes and tannins compounds.
For separation process accurred to green leaves with stems extract,
extracted by second method of extraction paper chromatography used,
using chloroform: methanol (85 : 15 V/V) as asolvent system which give
two spots indicates the presence of two compound separated.
For identification process occurred to green leaves with stems
extract, extracted by second method of extraction chemical analysis carried
out includes micro analysis for C, H and nitrogen elements which indicates
the following:-
C 43.725 H 6.101 N 0.835 and the determined m/z=698. And
spectroscopic analysis for UV, IR, mass and HNMR spectra which give the
molecular formula to active compound in active extract in Melia azedarach
plant is C46H65O5N2.
Therefore, this method is of value whenever green leaves with stems
extract, extracted by second method of extraction of Melia azedarach plant
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is to be using in pest control and reproducible results are desired.
Finally, the toxicity and insecticidal activity of each extract increase
with increasing the concentration.