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COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. How to cite this thesis Surname, Initial(s). (2012). Title of the thesis or dissertation (Doctoral Thesis / Master’s Dissertation). Johannesburg: University of Johannesburg. Available from: http://hdl.handle.net/102000/0002 (Accessed: 22 August 2017). Ethnobotanical uses, anatomical features, phytochemical properties, antimicrobial activity, and cytotoxicity of the Sotho medicinal plant Searsia erosa (Anacardiaceae) BY Nhlamulo Nomsa Mashimbye Dissertation submitted in fulfilment of the requirements for the degree of Masters in Botany In Botany and Plant Biotechnology Faculty of Science University of Johannesburg Supervisor: Professor A Moteetee Co-supervisor: Dr A Oskolskii Co-supervisor: Professor S van Vuuren (University of the Witwatersrand) April, 2019 Dedication I dedicate this dissertation to my mothers, Mrs T. A Mashimbye and Mrs Maluleke for raising my child while I continued with my research project, my daughter R. T Maluleke for putting up with my absence, and God, without whom this would not have been possible. iii Acknowledgements I would like to express my deepest appreciation to the following people for their support and contribution toward the completion of this research project: • My supervisor, Prof, A. Moteetee, for guidance, support and assisting throughout the study. • Co- supervisor, Dr A. Oskolskii, for the unhesitating support and guidance in the anatomical study. • Co- supervisor, Professor Sandy F. Van Vuuren, guidance and assistance through the microbiological study. • Departments of Chemistry and Food Technology and Biotechnology at the University of Johannesburg in assistance with the phytochemistry study. • National Research Foundation and The University of Johannesburg for funding iv Presentations at conferences • Searsia erosa (Anacardiaceae): Its ethnobotany, chemical properties, and antimicrobial activity. January 2017. University of the Western Cape, Cape Town. South African Association of Botanists (SAAB) – poster presentation. • Ethnobotanical uses, anatomical features and phytochemical properties of the Sotho medicinal plant Searsia erosa (Thunb) Moffett (Anacardiaceae). November 2017. University of Johannesburg. Department of Botany Postgraduate Symposium – oral presentation. • Ethnobotanical uses, anatomical features and phytochemical properties of the Sotho medicinal plant Searsia erosa (Thunb) Moffett (Anacardiaceae). January 2018. University of Pretoria, Pretoria. South African Association of Botanists (SAAB) – oral presentation. v Table of Contents Dedication ............................................................................................................................. ii Acknowledgements ............................................................................................................... iii Presentations at conferences ................................................................................................ iv Table of contents ................................................................................................................... v Abstract ............................................................................................................................... viii List of tables .......................................................................................................................... x List of figures ......................................................................................................................... xi Chapter one: Introduction .................................................................................................. 1 1.1 Background .................................................................................................................. 1 1.1.1 African traditional medicine .................................................................................... 2 1.1.2 Basotho traditional medicine .................................................................................. 2 1.2 The genus Searsia F.A. Barkley................................................................................... 4 1.2.1 Ethnobotanical uses of Searsia specie .................................................................. 6 1.2.2 Anatomical features of Searsia ............................................................................. 6 1.2.2.1 Trichomes ...................................................................................................... 6 1.2.2.2 Secretary canals… ......................................................................................... 8 1.3 Secondary metabolites in the family Anacardiaceae .................................................... 8 1.3.1 Terpenes or terpenoids ........................................................................................ 10 1.3.1.1 Essential oils…... .......................................................................................... 11 1.3.1.2 Saponins … .................................................................................................. 11 1.3.2 Phenolics ............................................................................................................. 12 1.3.3 Alkaloids .............................................................................................................. 13 1.4 Antimicrobial properties of Searsia species ............................................................... 13 1.4.1 Gastrointestinal problems .................................................................................... 14 1.4.2 Respiratory tract infections ................................................................................. 15 1.5. Cytotoxicity in Searsia species .................................................................................. 16 1.6 Aims and objectives of the study ................................................................................ 16 1.7 References ................................................................................................................. 18 Chapter two: Materials and methods ............................................................................... 28 2.1 Plant collection ........................................................................................................... 28 2.2 Anatomical procedures .............................................................................................. 28 2.3 Histochemistry ........................................................................................................... 29 2.3.1 Tannins test ......................................................................................................... 29 2.3.2 Phenolics test ...................................................................................................... 29 vi 2.3.3 Terpenoid test ...................................................................................................... 29 2.3.4 Mucilage test ....................................................................................................... 30 2.3.5 Lipid test .............................................................................................................. 30 2.4 Distillatiom of essential oils ........................................................................................ 30 2.4.1 Percentage yields of essential oils ....................................................................... 31 2.4.2 GC/MS analysis of essential oils ......................................................................... 31 2.4.3 GC/MS instrument and operating settings for analysis of S. erosa essential oil .. 31 2.4.5 Identification of components ................................................................................ 31 2.5 RP-HPLC analysis of S. erosa extract ....................................................................... 32 2.5.1. Preparation of extract ......................................................................................... 32 2.5.1.1 Aqueous extract ............................................................................................ 32 2.5.1.2 Preparation of mobile phase ......................................................................... 32 2.5.1.3 Preparation of calibration curve of tannic acid (internal standard) ................ 33 2.5.1.4 Preparation of sample (analyte) .................................................................... 33 2.5.2. Identification and confirmation ........................................................................... 34 2.6 Antimicrobial activity ................................................................................................... 34 2.6.1 Preparation and extraction of plant materials....................................................... 34 2.6.2 Test micro-organisms and incubation conditions ................................................. 36 2.6.2.1 Gastrointestinal microorganisms .................................................................. 36 2.6.2.2 General pathogens responsible for systemic infection ................................