assessment of bioactivity of selected plants against pests and microbes from agro-pastoral ...

150 Pages·2015·2.46 MB·English

ASSESSMENT OF BIOACTIVITY OF SELECTED PLANTS AGAINST
PESTS AND MICROBES FROM AGRO-PASTORAL COMMUNITIES IN
MBULU DISTRICT, TANZANIA

MICHAEL QWARSE

THESIS SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS
FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE IN
CHEMISTRY OF THE OPEN UNIVERSTY OF TANZANIA
2015
ii

CERTIFICATION
The undersigned certify that he has read and hereby recommend for acceptance by
the Open University of Tanzania, a thesis titled “Assessment of Bioactivity of Se-
lected Plants against Pests and Microbes from Agro-pastoral Communities in
Mbulu District, Tanzania” in fulfilments of the requirements for the degree of Mas-
ter of Science (Chemistry) by Thesis of the Open University of Tanzania.
____________________________
Dr. Matobola J. Mihale
(Supervisor)

____________________________
Date

____________________________
Dr. Joseph Sempombe
(Supervisor)

____________________________
Date
iii

COPYRIGHT
This dissertation is protected under the Berne Convention, the copyright Act of 1999
and other international and national enactments of intellectual property. No part of
this dissertation may be reproduced, stored in any retrieval system or transmitted in
any form by any means, electronic, mechanical, photocopying, recording or other-
wise without acknowledging the author or the Open University of Tanzania in that
behalf.
iv

DECLARATION
I, Michael Qwarse, do hereby declare that this thesis is my own original work and
that it has not been presented and will not be presented to any other University for a
similar or any other degree award.

____________________________
Signature

____________________________
Date
v

DEDICATION
This work is dedicated to my parents Xwatsal Margwet and Maria D. Deeng’w, my
wife Antonia Onna and my childrens Christopher Onna and Christopher M. Qwarse
for always being there for me all the time.
vi

ACKNOWLEDGEMENTS
I have no words to thanks God Almighty who bestow me this opportunity to com-
plete my study. I wish to express my profound gratitude to all who read the thesis
and in particular my supervisors, Dr. Matobola J. Mihale and Dr. Joseph Sempombe
for introducing me to this area and providing excellent scientific and personal advice,
guidance, critical comments, suggestions and encouragement in this study. They al-
ways supported me, had time for questions and discussions. I acknowledge the logi-
cal and critical criticism, comments, suggestions and encouragement provided by
Professor Veronica Mugoyela, Dr. Leonia Henry, and Dr. Fortunatus Sungwa.

I sincerely acknowledge the financial support I got from the Commission for Science
and Technology. I am highly indebted to the staff of Faculty of Science and Envi-
ronmental Studies, Open University of Tanzania (OUT), School of Pharmacy and
Institute of Traditional Medicine, Muhimbili University of Health and Allied Scienc-
es for their logistic and moral support.

I wish to express my sincere appreciation to beloved mum, Mrs Antonia Onna, My
children, Christopher Michael and Christopher Onna for their support and encour-
agements during my studies. I would like to express my gratitude to my colleagues at
MUHAS: Nelson Masota, Pius Ipagala and my friends all over Tanzania amongst
others: J. Siayi, Paschal P. Onna, Simon Vitalis, Reginald Barhe, Bahati Bryson,
Roger, and Zaituni Msegwa for their social and moral support.
vii

ABSTRACT
This study intended to have an ethnobotanical inventory of medicinal and pesticidal
plant species and their bioactivities and toxicity against selected bacteria, fungi and
storage pests. Bioactivities (antimicrobial and antioxidant activities) against disease
causing organisms, toxicity against brine shrmps, first filial generation (F1) progeny,
feeding deterrence and repellence against selected storage pests and quality grains
evaluation as well as phytochemicals profiles were determined using standard proce-
dures. A total of 66 dentifies plant species mainly from Minosoidaceae, Solanaceae,
and Euphobiaceae families were used for pesticidal and medicinal purposes with oral
route as the main route of administration and leaves as commonly used plant parts.
Antibacterial activities of selected plants were between 25% and 75% of the activity
of gentamycin sactivity. Antifungal activities of selected plant species varied from
0% to 55 % of the fluconazole activity. Antioxidant activity of Phytolacca dodecan-
dra roots measured by percent absorbance was 90% as compared to 98% of the Bu-
tylated Hydroxy Toluene (BHT) activity. Brine shrimp cytotoxicities ranges of P.
dodecandra, (LC = 4.6 – 34.7 µg/mL), Cynoglossum geometrium (LC = 71.09
50 50
µg/mL) and Ocimum filamentosum (LC = 28.08 µg/mL) are indicate potential cyto-
50
toxicity of plants. P. dodecandra leaf extracts killed 98% of Sitophilus zeamais and
99% of Tribollium castaneum at concentration of 150 mg/mL on day 3. Similarly, P.
dodecandra leaf extracts reduced grain damage to 0% and had moderate repellence
of 57% and 66% to Sitophilus zeamais and Tribollium castaneum, respectively. Little
effects of leaf extracts on the grain quality (seed damage, colour and odour) was ob-
served. Seed viability decreased to about 30% after 90 days. Isolation and structure
elucidation of bioactive ingredients in selected plant species is recommended.
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TABLE OF CONTENTS
CERTIFICATION .......................................................................................................... ii
COPYRIGHT ................................................................................................................. iii
DECLARATION ............................................................................................................ iv
DEDICATION ................................................................................................................. v
ACKNOWLEDGEMENTS ........................................................................................... vi
ABSTRACT ................................................................................................................... vii
TABLE OF CONTENTS ............................................................................................. viii
LIST OF TABLES ...................................................................................................... xvii
CHAPTER ONE ............................................................................................................. 1
GENERAL INTRODUCTION ...................................................................................... 1
1.1 Background of the Problem ................................................................................................ 1
1.2 Statement of the Problem .................................................................................................... 3
1.3 Objectives ................................................................................................................................ 5
1.3.1 General Objective ............................................................................................... 5
1.3.2 Specific Objectives ............................................................................................. 5
1.4 Research Questions ............................................................................................................... 5
1.5 Significance of the Study .................................................................................................... 6
CHAPTER TWO ............................................................................................................ 8
LITERATURE REVIEW ............................................................................................... 8
2.1 Plants as Sources of Bioactive Natural Products .......................................................... 8
2.2 Global Uses of Biomedicines and Biopesticides .......................................................... 9
2.2.1 Botanical Biomedicines in Tanzania ............................................................................. 10
2.2.2 Botanical Pesticides in Tanzania ...................................................................... 11
ix

2.3 Ethno-botanical Uses of Selected Plant Species ............................................... 14
2.3.1 Gymnema Sylverstre ......................................................................................... 14
2.3.1.1 Plant Description and Distribution.................................................................... 14
2.3.1.2 Traditional Uses of G. sylverstre ...................................................................... 15
2.3.2 Phytolacca dodecandra...................................................................................... 15
2.3.2.1 Plant Description and Distribution.................................................................... 15
2.3.2.2 Traditional Uses of P. dodecandra .................................................................... 16
2.3.3 Cynoglossum geometrium Bak and Wright ...................................................... 17
2.3.3.1 Plant Description and Distribution.................................................................... 17
2.3.3.2 Traditional Uses of C. geometrium ................................................................... 18
2.3.4 Leonotis Nepetifolia.......................................................................................... 18
2.3.4.1 Plant Description and Distribution.................................................................... 18
2.3.4.2 Traditional Uses of L. neptifolia ....................................................................... 19
2.3.5 Ocimum Filamentosum ..................................................................................... 19
2.3.5.1 Plant Description and Distribution.................................................................... 19
2.3.5.2 Traditional Uses of O. filamentosum ................................................................ 20
2.4 Biopesticidal Properties ..................................................................................................... 20
2.4.1 Antifeedants Properties ..................................................................................... 20
2.4.2 Pests Repellence Activity ................................................................................. 21
2.4.3 Toxicity Activity ............................................................................................... 21
2.5 Pharmacological Activities .............................................................................................. 22
2.5.1 Antioxidant Activities ....................................................................................... 22
2.5.2 Antimicrobial Activity ...................................................................................... 23
2.6 Phytochemical Profiling .................................................................................................... 24
2.6.1 Phenols .............................................................................................................. 24
x

2.6.2 Alkaloids ........................................................................................................... 25
2.6.4 Terpenoids (Isoprenoids) .................................................................................. 25
2.6.5 Saponins ............................................................................................................ 26
2.6.6 Tannins .............................................................................................................. 26
2.6.7 Glycosides ........................................................................................................ 26
CHAPTER THREE ...................................................................................................... 28
MATERIALS AND METHODS ................................................................................. 28
3.1 Study Area ............................................................................................................................. 28
3.2 Plant Materials .................................................................................................. 29
3.3 Research Approach ............................................................................................................. 30
3.4 Sample Collection and Botanical Identification ......................................................... 32
3.5 Sample Preparation ............................................................................................................. 32
3.6 Sample Extraction ............................................................................................................... 33
3.7 Antimicrobial Activities .................................................................................................... 33
3.7.1 Test Organisms ................................................................................................. 33
3.7.2 Preparation of Culture Media............................................................................ 34
3.7.3 Antibacterial Activity........................................................................................ 34
3.7.4 Antifungal Activities ......................................................................................... 34
3.7.5 Minimum Inhibitory Concentration, (MIC) ................................................................. 35
3.8 DPPH Free Radical Scavenging (Antioxidant) Activity .......................................... 36
3.8.1 DPPH Qualitative Assay ................................................................................... 36
3.8.2 DPPH Quantitative Assay ................................................................................. 36
3.9 Brine Shrimps Test .............................................................................................................. 37
3.10.1 Mass Rearing of the Pests ................................................................................. 38
3.10.2 Contact Toxicity and First fillial Generation (F1) Progeny Studies ................. 39