ISOLATION AND PARTIAL PURIFICATION OF LECTINS FROM THE STEM BARK OF ORDEAL TREE (Erythrophleum suaveolens) AND THEIR POSSIBLE LARVICIDAL ACTIVITIES AGAINST Culex quinquefasciatus
ISOLATION AND PARTIAL PURIFICATION OF LECTINS FROM THE STEM BARK OF ORDEAL TREE (Erythrophleum suaveolens) AND THEIR POSSIBLE LARVICIDAL ACTIVITIES AGAINST Culex quinquefasciatus
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Date
2013-02
Authors
IHUOMA, NYEYIRICHI
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Abstract
ABSTRACT
Lectins from the saline extract of Erythrophleum suaveolens stem bark, were isolated,
partially purified, characterized and evaluated in terms of their larvicidal properties
against Culex quinquefasciatus. Purification was done by precipitation with ammonium
sulfate at 20% - 90% saturation. The ammonium sulfate precipitate was subjected to gel
filtration using Sephadex G-75 resin. The two fractions with the highest heamaglutinating
activity were further subjected separately to ion-exchange chromatography using Sp-
Sephadex C-50 resin. The lectins in the crude extract and the purified lectins appeared as
five bands at positions 38KDa, 28KDa, 26KDa, 11KDa and 9KDa on a SDS-PAGE
electrophoregram. The lectins were found to be stable at the temperature range of 30-
600C and pH range of 3-7. The carbohydrate content of the crude extract, Gel I, Gel II,
Ion I and Ion II peaks were 0.04%, 0.04%, 0.03%, 0.02%, and 0.01% respectively and
showed specificity to mannose and galactose. A series of nine concentrations of the
extracts ranging from 0.0001 mg/L, 0.001 mg/L, 0.01 mg/L, 0.1 mg/L, 1mg/L, 5mg/L, 10
mg/L, 50 mg/L and 100mg/L were tested against the third instar larvae of Culex
quinquefasciatus and their percentage mortalities and LC50 values were obtained. The
crude extract of Erythrophleum suaveolens show very high larvicidal activity with 96%
mortality achieved at a concentration of 100 mg/L and had an LC50 of 4.39 mg/L. The gel
peaks of Erythrophleum suaveolens showed larvicidal activities to Culex
quinquefasciatus larvae with 74.67% and 69.33% mortality achieved at a concentration
of 100 mg/L and had LC50 of 43.73mg/L and 43.65mg/L respectively. The ion exchange
purified extracts of Erythrophleum suaveolens showed low larvicidal activity to Culex
quinquefasciatus larvae with 10.67% and 9.33% mortality achieved at a concentration of
100 mg/L respectively. These results suggest that the saline stem bark extract of
Erythrophleum suaveolens is promising as a larvicide against mosquito larvae and can be
used directly in small volumes in aquatic habitats and in mosquito population
management programme.
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Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILMENT OF THE
REQUIREMENT FOR THE AWARD OF MASTER OF SCIENCE IN
BIOCHEMISTRY
Keywords
ISOLATION, PARTIAL PURIFICATION, LECTINS, STEM, BARK, ORDEAL TREE (Erythrophleum suaveolens), LARVICIDAL ACTIVITIES, AGAINST Culex quinquefasciatus