Antimicrobial activity of the bark extracts of Entada abyssinica

345 Pages·2017·7.91 MB·English

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Antimicrobial activity of the
bark extracts of Entada
abyssinica (omwoolola)
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• A doctoral thesis submitted in partial fulfilment of the requirements for
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ANTIMICROBIAL ACTIVITY OF THE BARK
EXTRACTS OF ENTADA ABYSSINICA
(OMWOOLOLA)
by
Mary Grace Nambatya, Bsc. Msc. Dip Educ.
A Doctoral Thesis
Submitted in Partial Fulfilment of the
Requirements for the Aw ard of the Degree of
Doctor of Philosophy
of
Loughborough University of Technology
August 1993
Supervisor; Dr. W. G. Salt, B Pharm, PhD, MPS, CBiol, MIBiol.
© by Nambatya M. G. 1993.
Loughborough University ,
of Technology Library
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ACKNOWLEDGEMENTS
I would like to extend special thanks to my supervisor, Dr. W. G. Salt for the
supervision of this project and helpful advice in the writing up of this manuscript. To
Prof. B. Marples, for his help and guidance, and to the technical staff with whom I've
been involved, including Jill Thorley, John Brennan, John Kershaw and John
Greenfield
r
m very grateful to the Kulika Charitable Tmst for funding this project and supporting
me financially throughout my studies in this country. To Bishop Matthias
Ssekamaanya, Bishop Joseph Mukwaaya, My Boss, Mr. Nathan Mubiru of the Natural
Chemotherapeutics research centre in Uganda, and Mr and Mrs Cullingford for their
support. To my grandfather, Mr. B. Mayanja and Br./Fr. Anatoli for all their
information concerning the Ugandan medicinal plants, and my parents and relatives for
encouragement.
I'm grateful to friends who have given me invaluable help throughout this project
especially; Dr. Ernest Attafuah for additionally sacrificing his precious time to proof
read part of this manuscript. To John Bikangaga, for his encouragement and help with
the computing work. Special thanks to Mr Charles Mutumba and Mr James Ssekaayi
and their families, for always trying against the odds to send me the required bark
samples for research. To Mr. Robert Mudima and family, for encouragement, and
support without which life during the last half of my project would have been very
difficult. To Mr. B. L. Ogunsola and Dr. Catherine Karekezi for their encouragement. I
also say thank you to my colleagues in the laboratory, for making the atmosphere a
comfortable one to work in.
In a special way, I'm thankful to my boy friend, Eugene Larbi for his love, support,
encouragement and patience. Special thanks to the staff of the Centre for Scientific
Research into plant medicine, Mampong-Akwapim. Ghana, West Africa, for their
valuable information concerning medicinal plant analysis protocols. To friends in
Loughborough and London, including Mr and Mrs Katungi, Josephine and Regina
Kiwanuka for their prayers and encouragement. To crown it all, I thank the Almighty
God who has channelled his help through all people acknowledged or not
acknowledged for the realisation of this project.
ii
ORIGINALITY
I This is to certify that I am responsible for the work submitted in this thesis, that the
original work is my own except as specified in acknowledgements or in footnotes, and
that neither the thesis nor the original work contained therein has been submitted to
this or any other institution for a higher degree.
MARY GRACE NAMBATYA
August 1993
iii
ABSTRACf
Various extracts of Entada abyssinica stem/root bark have been shown to have
antimicrobial activity using organisms : Staphylococcus aureus, S. epidennidis,
Escherichia coli, Pseudomonas aeruginosa, Bacillus megateriwn, Candida albicans,
Aspergillus niger and Tricophyton mentagrophytes on solid media. Chromatographic
analysis of the bark extracts of different trees (according to age), showed them to
contain in common the components responsible for the observed antimicrobial activity
with differences observed in minor bands not of antimicrobial importance.
Procedures for biological activity guided extraction and purification of active
components from the biological matrix, were developed leading in particular to two
compounds of interest: C-l and C-2, which showed good antibacterial activity. Other
active compounds isolated in the process were: B3 and B4 with both antibacterial and
antifungal properties. B2 (with no antimicrobial value) was also isolated
Spectroscopic studies of C-2 and B3 involving; UV, JR, IH NMR, MS and FAB-MS,
indicated C-2 to contain an unsaturated lactone structure as found in cardenolides,
which was confirmed by comparing results with those of ouabain (g-strophanthin),
used as a cardenolide standard. B3 was characterised as oxalic acid. The spectroscopic
results (C-2) were a confirmation offmdings with the chromogenic spray reagents used
in 1LC analyses, which were suggestive of presence of steroid and lactone moieties in
C-2. A steroid structure was also indicated in C-l by chromogenic reagent 1LC spray
results, but the sample was in very low amounts for any meaningful spectroscopic
studies to be carried out.
Properties for example, physical and antimicrobial were studied for all the isolates
while chemical property studies were carried out for C-2. A justification for use of
Entada abyssinica and ways in which the crude extracts could be rendered more useful
are discussed. Some comments on the structure activity relationship of C-2 are
included
iv