PHYTOCHEMICAL SCREENING AND LARVICIDAL EFFECTS OF BORRERIA VERTICILLATA(LINNAEUS) AND STRIGA ASIATICA(LINNAEUS) AGAINST CULEX QUINQUEFASCIATUS (SAY)
PHYTOCHEMICAL SCREENING AND LARVICIDAL EFFECTS OF BORRERIA VERTICILLATA(LINNAEUS) AND STRIGA ASIATICA(LINNAEUS) AGAINST CULEX QUINQUEFASCIATUS (SAY)
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Date
2017-01
Authors
KONTAGORA, FATIMA GARBA
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Abstract
The phytochemicals solvent-derived extracts of Borreriaverticillata(Linnaeus) and
Strigaasiatica(Linnaeus) and their larvicidal effects against Culexquinquefasciatus(Say)
were examined. Each of the two pulverized plant materials were initially subjected to
soxhlet extraction method using N-hexane, chloroform, ethyl-acetate and methanol in
that order of increasing polarity of the solvents. The various solvent extracts were
subjected to preliminary phytochemical screening ofcompounds.Bioassay of plants
extracts on late third larval instars of Culexquinquefasciatus was tested in the laboratory
using2.00 mg/l, 4.00 mg/l, 6.00 mg/l and 8.00 mg/l concentrations.Twenty-five (25) late
third instars larvae of Cx. quinquefasciatus in triplicates for each concentration and the
control devoid of extractswere isolated from the culture media into a test bowl using a
dropping pipette. The preliminary phytochemical screeningof the plant extracts revealed
the following compounds of insecticidal importance in different proportions: alkaloids,
flavonoids, saponins, unsaturated steroid and triterpenes,tannins and cardiac glycosides
while anthraquinone was absent in all the plantextracts.Larvicidal effects of theplant
extracts ofBorreria verticillata and Striga asiatica were dose-dependent,except the
chloroform plant extractof Borreria verticillata,which increased and subsequently
decreased with further increase in the concentration of the plant extract. The median
lethal concentration (LC50) values ofmethanolic, ethyl-acetate, n-hexane and chloroform
solvent extracts were 17.49 mg/l, 8.67mg/l, 1.60 mg/l and 1.184×1030 mg/l respectively
for Borreriaverticillata. The LC50 values ofStrigaasciatica for solvent extracts
ofmethanol, ethyl-acetate, n-hexane and chloroform were found to be 12.91mg/l, 3.01
mg/l, 1.45 mg/l and 3.03 mg/lrespectively. The results of the phytochemical screening of
the solvent extracts of B.verticillata and S.asiatica have shown that both weeds with the
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later being a parasitic weed, have a beneficial side, and part of their benefits was
demonstrated in the larval mortality exhibited by the plant extracts. The larval mortality
observed wasattributed to the presence of polar compounds such as
alkaloids,flavonoids,tannins,saponins,cardiac glycosides and the polar
compound,triterpenein the methanolethyl-acetate and n-hexane solvent of B.verticillata
and S.asiatica.It was concluded that,Borreriaverticillataand Strigaasciaticamay be used
in the management of noxious mosquito species and serve as alternatives to synthetic
insecticides that have many health implications and environmental problems. It
isrecommended that, the use of B.verticillata and S.asiatica extracts need to be tested in
the field to ascertain their full potentials.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES, AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF
MASTER DEGREE IN BIOLOGY.
DEPARTMENT OF BIOLOGY,
FACULTY OF LIFE SCIENCES,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
Keywords
PHYTOCHEMICAL SCREENING,, D LARVICIDAL EFFECTS,, BORRERIA VERTICILLATA(LINNAEUS), STRIGA ASIATICA(LINNAEUS) ,, CULEX QUINQUEFASCIATUS (SAY)