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). STUDIES ON THE MEDICINALLY IMPORTANT RHYNCHOSIA (PHASEOLEAE, FABACEAE) SPECIES: TAXONOMY, ETHNOBOTANY, PHYTOCHEMISTRY AND ANTIMICROBIAL ACTIVITY BY MASHIANE SONNYBOY MOTHOGOANE 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.N. Moteetee April, 2019 DECLARATION I Mashiane Sonnyboy Mothogoane, declare that this dissertation submitted by me for the degree of Masters in Botany at the Department of Botany and Plant Biotechnology in the Faculty of Science at the University of Johannesburg is my own work in design and execution. It has not been submitted before for any degree or examination at this or any other academic institution and that all the sources that I have used or quoted have been indicated and acknowledged by means of complete references. 15/04/2019 ________________________ _____________________ SIGNATURE DATE (MR M S MOTHOGOANE) i DEDICATION I would like to dedicate this work to my family, parents, Sejeng Magdeline Mothogoane and Mmile William (late) for all the encouragement throughout my school years. I am also deeply grateful to wife, Lorraine Phumzile Mothogoane and my children, Dayan Uriah Mothogoane and Lemuela Amalia Mothogoane, for all their love, support and inspiration throughout this study project. ii ACKNOWLEDGEMENTS I wish to express my sincere thanks to the many persons and institutions who have offered encouragement, assistance and co-operation in the preparation of this dissertation, namely: Prof. A.N. Moteetee, my supervisor, for her guidance, advice and approval of the study project. The South African National Biodiversity Institute (SANBI), my employer, for financial support and allowing me to do my research in a professional and academic environment. The directors and curators of the herbaria that provided material for study and images of specimens, and image of type specimen that was not available on loan; Bolus Herbarium (BOL), Selmar Schonland Herbarium (GRA), Compton Herbarium (NBG), KwaZulu-Natal Herbarium (NH), Bews Herbarium (NU), National Herbarium (PRE), and National Herbarium Namibia (WIND). Dr Janine Victor (SANBI) for assistance with project proposal and editing. Mary Gunn Library (SANBI) for books, journals and assistance with literature searches. Messieurs Thabo Masupa and William Sepheka for assistance and good company in fieldwork. Mrs Phumzile Moerane and Prof. Sandy Van Vuuren for assistance with antimicrobial laboratory experiments at Wits University. iii CONFERENCE PRESENTATIONS Mothogoane, M.S., and Moteetee A.N., 2018. Studies on the medicinally important southern African Rhynchosia species (Phaseoleae, Fabaceae): their taxonomy, ethnobotany, phytochemistry and antimicrobial activity. Podium presentation at the 44th SAAB annual conference held at University of Pretoria, Pretoria, 09 -12 January, 2018. Mothogoane, M.S., and Moteetee A.N., 2017. Studies on the medicinally important southern African Rhynchosia species (Phaseoleae, Fabaceae): their taxonomy, ethnobotany, phytochemistry and antimicrobial activity. Podium presentation at the 43rd SAAB annual conference held at Lagoon Beach Hotel, Cape Town, 08 - 11 January, 2017. Mothogoane, M.S., and Moteetee A.N., 2017. Studies on the medicinally important southern African Rhynchosia species (Phaseoleae, Fabaceae): their taxonomy, ethnobotany, phytochemistry and antimicrobial activity. Oral presentation for the 7th Post Graduate Symposium. Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, 06 - 07 November 2017. Mothogoane, M.S., and Moteetee A.N., 2016. Studies on the medicinally important southern African Rhynchosia species (Phaseoleae, Fabaceae): their taxonomy, ethnobotany, phytochemistry and antimicrobial activity. Oral presentation for the Post Graduate Symposium. Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, 15-16 November 2016. iv ABSTRACT The genus Rhynchosia Lour. was first introduced by Loureiro, to accommodate the species Rhynchosia volubilis Lour. It derives its name from the Greek word “rhynchos” which means a beak, snout or horn, in reference to the shape of the keel petals. Rhynchosia is a relatively large genus with more than 230 species occurring throughout the tropics and subtropics, with about 77 species indigenous to southern Africa. Within the subtribe Cajaninae, Rhynchosia is closely related to the genus Eriosema (DC) Desv. However, it can be distinguished from the latter by the structure of the funicular attachment of the seed in relation to the hilum. In Rhynchosia the funicular attachment is in the centre of the hilum, while in Eriosema the attachment is at the end of the hilum. It also has affinities with the genus Bolusafra Kuntze, however, previous preliminary molecular studies have shown that Bolusafra is congeneric with Rhynchosia. This project is part of ongoing taxonomic studies in the type section Rhynchosia, and its main aim was to revise the R. minima complex and provide a synopsis of the ethnomedicinally important species. The secondary aim of the study was to screen these plants for their antimicrobial activities based on their traditional use. However, due to unavailability of some of the plants in the field, despite numerous attempts, not all species could be screened. The third aim was to conduct qualitative evaluation of the phytochemical properties of these plants. The morphological studies were conducted by examining herbarium specimens and during field surveys, while type specimens were studied online. Taxonomic studies revealed that there are five infraspecific taxa in the R. minima complex in southern Africa, these include two newly described varieties (R. minima (L.) DC. var. glandularis M.S. Mothogoane and Moteetee and R. minima (L.) DC. var. magniflora M.S. v Mothogoane and Moteetee). A taxonomic key to the infraspecific taxa of R. minima complex is provided, in addition, the correct nomenclature, typification, and distribution maps for all taxa studied are presented. Various literature sources and databases were consulted for the compilation of ethnomedicinal Rhynchosia species. The survey showed that in addition to R. minima, there are eight other ethomedicinally important species of Rhynchosia species in southern Africa, namely; R. adenodes Eckl. & Zeyh., R. albissima Gand., R. caribaea (Jacq.) DC., R. densiflora (Roth) DC., R. harveyi Eckl. & Zeyh., R. hirta (Schumach.) Meikle, R. resinosa (Hochst.ex A.Rich.) Meikle, and R. sublobata. These species are used for the treatment of various human infections, including gastrointestinal disorders, respiratory tract infections (RTIs), skin conditions, and sexually transmitted infections (STIs). However, only three of these species (R. adenodes, R. caribaea and R. harveyi) are used medicinally in southern Africa, while the others are used elsewhere across their wider geographical distribution ranges. Based on the microbial inhibitory concentrations (MIC) results, Rhynchosia hirta and R. sublobata showed noteworthy antibacterial activities against Escherichia coli and Staphylococcus aureus, which are the major causative pathogens for gastrointestinal problems such as diarrhoea (This explains the efficacy of these species in the treatment of stomach problems). The studied species (R.adenodes, R.albissima, R. caribaea, R.hirta, R.minima and R.sublobata) were found to contain a number of chemical constituents including, alkaloids, coumarins, flavonoids, phenols, saponins, tannins, and terpenoids, which might explain the ethnobotanical uses of these species in traditional medicine. vi Table of Contents DECLARATION ............................................................................................................... i DEDICATION ...................................................................................................................ii ACKNOWLEDGEMENTS ............................................................................................... iii CONFERENCE PRESENTATIONS ................................................................................iv ABSTRACT ..................................................................................................................... v LIST OF FIGURES ..........................................................................................................ix LIST OF TABLES .......................................................................................................... xii LIST OF ABBREVIATIONS, ACRONYMS AND SYMBOLS ........................................ xiii CHAPTER 1: INTRODUCTION....................................................................................... 1 1.1