LARVICIDAL POTENTIAL OF THE LEAF EXTRACT OF Datura stramonium AND Occimum gratissimum AGAINST Culex quinquefasciatus MOSQUITO SPECIES
LARVICIDAL POTENTIAL OF THE LEAF EXTRACT OF Datura stramonium AND Occimum gratissimum AGAINST Culex quinquefasciatus MOSQUITO SPECIES
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Date
2013-10
Authors
D.G, CHINTEM Williams
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Abstract
The study evaluated the Larvicidal effect of Aqueous, Ethanol, Ethylacetate, n-Hexane and partially purified fraction of two indigenous medicinal plant; Datura stramonium and Occimum gratissimum. Different concentrations of 6.25, 12.50, 25.00, 50.00, 100.00 and 1,000ppm were prepared from the stock solution of the samples. Third and forth instar larva of Culex quinquefasciatus where exposed to these different graded concentrations and mortalities were observed at time intervals. The presence of alkaloid, Tannins and Terpenoids detected in D. stramonium Ethanol extract while Sterols, flavonoids, Alkaloids and saponins where present in O. gratissimum n-Hexane extract. The effective larval mortality was observed in ethanol extract of Datura stramonium and Occimum gratissimum n-hexane extract against Culex. Quinquefasciatus mosquito larvae (percentage mortality = 96% and 100% at 1000ppm after 24hr whereas LD50=2.565 and 2.515ppm; LD90=17.724 and 30.511ppm, respectively) whereas ethylacetate and aqueous recorded poor mortality. There are strong correlation between mortalities observed in larvae and extract concentration; R2 = 0.161 and 0.152. On purification using column chromatographic methods, fractions from the crude extracts with the highest larval mortality was found in the DSEE-F1 and OGnHE-F3 displayed high larvicidal activity with percentage mortality of 99% at 100ppm and 100% at 50ppm against C. quinquefasciatus respectively, after 24hr respectively. Lethal concentrations were (LC50 = 4.390, and 1.485ppm respectively. The GCMS result for the larvicidal active fraction revealed the following compounds for DSEE-F1; Glycerin (22.19%), 6-Pentyl-5,6-dihydro-2H-pyran-2-one, 2,2-Dimethylpropanoic acid (26.49%), tridec-2-ynyl ester (12.21%), Hexadecanoic acid (19.16%), Heneicosane (7.59%) and Di-n-octyl phthalate (12.36%) while OGnHE revealed (7) compounds; Thymol (24.34%), Caryophyllene oxide (10.91%), Hexahydrofarnesyl acetone (7.67%), Stearic acid-methyl ester (4.88%), DELTA.8-Tetrahydrocannabinol (6.56%), 2-Ethylhexyl chloroformate (4.28%) and Di-n-octyl phthalate (41.36%). Further purification step of the fraction by pre-TLC showed a single band while the GCMS of revealed presence of Heneicosane and Caryophyllene oxide in fraction one of D. stramonium ethanollic extract and O. gratissimum n-hexane extract respectively. In conclusion the fractions from the leaf of ethanol extract of D. stramonium and O. gratissimum n-hexane extract showed potent toxicity against Cx. quinquefasciatus larvae. The present work revealed that these compounds could be used as environmentally sound larvicidal agent for mosquito control. Keywords:Larvicidal activity, Datura stramonium, Occimum gratissimum, Culex quinquefasciatus, Chromotographic, GCMS
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LARVICIDAL POTENTIAL OF THE LEAF EXTRACT OF Datura stramonium AND Occimum gratissimum AGAINST Culex quinquefasciatus MOSQUITO SPECIES
BY CHINTEM Williams D.G (B. Tech. (Hons) Biochemistry FUTY, 2009) M.Sc./SCIE/1043/2011-2012 A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY ZARIA NIGERIA IN PARTIAL FULFILMENT FOR THE AWARD OF MASTERS OF SCIENCE IN BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY ZARIA
OCTOBER, 2013
Keywords
LARVICIDAL, LEAF EXTRACT, Datura stramonium, Occimum gratissimum