PHYTOCHEMICAL, ANTIOXIDANT AND ANTISNAKE VENOM STUDIES OF THE METHANOL EXTRACT OF THE ROOT BARK OF PHYLLANTHUS MUELLERIANUS (KUNTZE) EXCELL
PHYTOCHEMICAL, ANTIOXIDANT AND ANTISNAKE VENOM STUDIES OF THE METHANOL EXTRACT OF THE ROOT BARK OF PHYLLANTHUS MUELLERIANUS (KUNTZE) EXCELL
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Date
2014-09
Authors
OKOLO, Ephraim Ayegba
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Abstract
Phyllanthus muellerianus is distributed in secondary forests from Guinea-Bissau, Mali,
West Cameroons and other parts of tropical Africa. It is a shrub or climber deciduous
and occasionally arborescent. The root bark of this plant was extracted by maceration
using methanol. The preliminary phytochemical screening of the methanol extract
indicates the presence of terpenoids, flavonoids, tannins, saponins, alkaloids and
carbohydrates. The methanol extract was then dissolved in water and partitioned with nhexane,
ethyl acetate and n-butanol. The partitioned n-butanol fraction was subjected to
column chromatography, gel filtration chromatography and then preparative thin layer
chromatography to yield a brown pentasaccharide PA - α-D-Glcp-(2 6)-[ α-D-Fruf(1
2)]α-D-Fruf-(1 4)β-D-Glcp-(2 2)β-D-Fruf and sucrose PX - α-D-Glcp-(1 2)α-D-Fruf
which is whitish in colour. The structures of the compounds were resolved using UV,
IR, 1D- and 2D-NMR spectral results. n-Butanol was also added to the dry methanol
extract. The n-butanol fraction of the dry crude extract was also subjected to gel
filtration chromatography and preparative thin layer chromatography to give a brown
amino alcohol glycoside CP1 – (2S, 3S, 4S, 5R)-2-((E)-3,10-diaminoicos-5-enyloxy)-
tetrahydro-6-(hydroxymethyl)-2H-pyran-3,4,5-triol. The LD50 and LD99 in mice of the
methanol extract and the venom of Naja nigricollis were determined to be 400mg/kg
and 9.55mg/kg using Lorke’s method and probit analysis respectively. Different doses
of the methanol extract and the LD99 of the venom were used for in vitro and in vivo
detoxification studies in mice. The extract exhibited 67% protection against lethality at
an administered dose of 20mg/kg, 83% at 40mg/kg and 33% at 80mg/kg of the extract
in vitro while there was 50% protection against lethality at an administered dose of
10mg/kg in vivo. The isolated pentasaccharide exhibited a free radical scavenging
activity comparable to that of vitamin C at 95% confidence level using DPPH as the standard free radical and methanol as solvent. Conclusively, the root bark of the plant is
rich in saccharides and the ethnomedicinal claim as to the antivenin properties of the
root bark of Phyllanthus muellerianus has been scientifically validated.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE
IN PHARMACEUTICAL AND MEDICINAL CHEMISTRY
DEPARTMENT OF PHARMACEUTICAL AND MEDICINAL CHEMISTRY,
FACVULTY OF PHARMACEUTICAL SCIENCE,
AHMADU BELLO UNIVERSITY,
ZARIA-NIGERIA
Keywords
PHYTOCHEMICAL,, ANTIOXIDANT,, ANTISNAKE VENOM STUDIES,, METHANOL EXTRACT,, ROOT BARK,, PHYLLANTHUS MUELLERIANUS,, EXCELL.