Structure, Biology and Chemistry of Plumbago Auriculata (Plumbaginaceae)
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Structure, Biology and Chemistry of Plumbago auriculata (Plumbaginaceae) By Karishma Singh A dissertation submitted in partial fulfillment of the academic requirements for the degree of Doctor of Philosophy in Biolgical Sciences School of Life Sciences College of Agriculture, Engineering and Science University of Kwa-Zulu Natal Westville Durban South Africa 30 November 2017 i DEDICATION To my daughter Ardraya Naidoo, she has given me the strength and encouragement to excel and be a positive role model for her. “Laying Down the Footsteps She Can Be Proud To Follow” ii ABSTRACT Plumbago auriculata Lam. is endemic to South Africa and is often cultivated for its ornamental and medicinal uses throughout the world. Belonging to the family Plumbaginaceae this species contains specialized secretory structures on the leaves and calyces. This study focused on the micromorphological, chemical and biological aspects of the species. Micromorphological studies revealed the presence of salt glands on the adaxial and abaxial surface of leaves and two types of trichomes on the calyces. “Transefer cells” were reported for the first time in the genus. The secretory process of the salt glands was further enhanced by the presence of mitochondria, ribosomes, vacuoles, dictyosomes and rough endoplasmic reticulum cisternae. Histochemical and phytochemical studies revealed the presence of important secondary metabolites that possess many medicinal properties which were further analyzed by Gas chromatography-mass spectrometry (GC-MC) identifying the composition of compounds in the leaf and calyx extracts. A novel attempt at synthesizing silver nanoparticles proved leaf and calyx extracts to be efficient reducing and capping agents that further displayed good antibacterial activity against gram- positive and gram-negative bacteria. Biological studies revealed for the first time the presence of three variants of flower colour (white, pale blue and deep blue) and each colour had a characteristic sex-morph described as “Pin” or “Thrum.” Due to the “Pin” and “Thrum” scenario, plants are reported to be self-incompatible. However, the findings of this study suggested that plants were also self-compatibile. Graphical demonstration of calyx trichomes showed their involvement in insect entrapment often resulting in the death of the insect due to the struggle to free itself. This study concludes that P. auriculata is of good medicinal value and can contribute towards drug development and other medicinal uses in traditional markets as well as in the cosmetic and pharmacological industries. This species has striking morphological and biological features and possesses good value for future perspectives. iii PREFACE The experimental work described in this Thesis was carried out in the School of Life Sciences, University of Kwa-Zulu Natal, Westville Campus, Durban, from March 2015 to November 2017, under the supervision of Prof Yougasphree Naidoo and co-supervision of Prof Himansu Baijnath. These studies represent original work by the author and have not otherwise been submitted in any form for any degree or diploma to any tertiary institution. Where use has been made of the work of others it is duly acknowledged in the thesis. As the candidate’s supervisors we have approved this thesis for submission. Supervisor: Signed: ______________ Name: Prof Yougasphree Naidoo Date: ________ Co-Supervisor: Signed: ______________ Name: Prof Himansu Baijnath Date: _________ iv DECLARATION 1- PLAGIARISM I, Mrs Karishma Singh declare that: 1. The research reported in this Thesis, except where otherwise indicated, is my original research. 2. This Thesis has not been submitted for any degree or examination at any other tertiary institution. 3. This Thesis does not contain other person’s data, graphs, pictures or other information, unless specifically acknowledged as being sourced from other persons. 4. This Thesis does not contain other persons’ writing, unless specifically acknowledged as being sourced from other researchers. Where other written sourced have been quoted, then: a. Their words have been re-written but the general information attributed to them had been referenced. b. Where their exact words have been used, then their writing has been placed in italics and within quotation marks, and referenced. 5. This Thesis does not contain texts, tables, graphs, figures or graphics copied and pasted from the internet, unless specifically acknowledged and the source being detailed in the thesis and in the References sections. Signed……………………… v DECLARATION 2- PUBLICATIONS DETAILS TO CONTRIBUTION TO PUBLICATIONS that form part and/include research presented in this thesis (include publications in preparation, submitted, in press, and published and give details of the contributions of each author to the experimental work and writing of each publication). Publication 1 Karishma Singh, Yougasphree Naidoo, Himansu Baijnath. 2018. A comprehensive review on the genus Plumbago with focus on Plumbago auriculata (Plumbaginaceae). Submitted 1/06/2017 to African Journal of Traditional, Complimentary and Alternative Medicine. Accepted for publication 02/10/2017. Published Contributions: Karishma Singh collected data and wrote manuscript. Prof Naidoo and Prof Baijnath edited the manuscript. Publication 2 Karishma Singh, Yougasphree Naidoo, Vishal Bharuth, Himansu Baijnath. 2017. Micromorphology and histochemistry of the secretory apparatus of Plumbago auriculata Lam. Submitted to South African Journal of Botany. Awaiting comments. Contributions: Karishma Singh carried out experimental work, recorded data and wrote manuscript. Vishal Bharuth recorded the Transmission Electron Microscopy aspect of the study. Prof Naidoo and Prof Baijnath provided comments and edited the manuscript. vi Publication 3 Karishma Singh, Yougasphree Naidoo, Channangihalli Thimmegowda Sadashiva, Himansu Baijnath. 2017. Gas chromatography-mass spectrometry analysis and phytochemical screening of Plumbago auriculata Lam. leaf and calyx extracts. Submitted to Asian Pacific Journal of Tropical Medicine. Awaiting comments. Contributions: Karishma Singh carried out experimental work, recorded data and wrote manuscript. Dr Sadashiva assisted in writing the results section of the manuscript. Prof Naidoo and Prof Baijnath were supervisors and edited the manuscript. Publication 4 Karishma Singh, Yougasphree Naidoo, Chunderika Moktar, Himansu Baijnath. 2017. Biosynthesis of silver nanoparticles using Plumbago auriculata Lam. leaf and calyx extracts and evaluation of their antimicrobial activities. Submitted to Advances in Natural Science: Nanoscience and Nanotechnology. Article in Press Contributions: Karishma Singh carried out experimental work, recorded data and wrote manuscript. Prof Naidoo and Prof Baijnath were supervisors and provided comments. Dr Moktar edited the manuscript and allowed the use of her facilities. Publication 5 Karishma Singh, Yougasphree Naidoo, Himansu Baijnath. Floral biology of Plumbago auriculata (Plumbaginaceae) and associated plant- insect interactions. Submitted to Turkish Journal of Botany. Awaiting comments. Contributions: Karishma Singh carried out experimental work, recorded data and wrote manuscript. Prof Naidoo and Prof Baijnath were supervisors and provided comments and edited the manuscript. vii ACKNOWLEDGEMENTS It is a real honour to thank the many people that made this thesis possible Prof Yougasphree Naidoo, my supervisor, for her consistent support, guidance and advice as well as an NRF grantholder-linked bursary in the first year of study. Prof Himansu Baijnath, my co-supervisor, for his unconditional motivation. His persistent nature, constant guidance and support has empowered me to work hard. Dr Chunderika Mocktar for her advice, assistance and use of her laboratory facilities. The Microscopy and Microanalysis unit, The Department of Chemistry, The Department of Pharmaceutical Science, UKZN, has made their support available in a number of ways. The National Research Foundation (NRF) for funding this degree and International Conference Attendance. Dr Nishani Harinarain for assisting with editing the final thesis. I am deeply thankful to many of my colleagues for their support, advice and encouragement throughout this degree especially Dr Depika Dwarka, Dr Sadashiva, Ms Nelisha Murugan, Mr Vishal Bharuth, Mr Subashen Naidu, Dr Kogie Moodley, Dr Karmini Murduray, Ms Valentina Govender, Ms Unarine Rambau, Ms Nozipho Nxumalo, Fallon Kemp and Mr Ashlin Munsamy. My Husband, Laven, for his unlimited support and understanding. He has always been my pillar of strength. My babygirl Ardraya, my pride and joy, she has given me the strength to see this degree right to the end. Last, but not least my parents for raising me, educating me and always encouraging me to achieve my goals. Their unconditional love and support has made me the woman I am today. viii TABLE OF CONTENTS Page DEDICATION…………………………………………………………………………………...ii ABSTRACT……………………………………………………………………………………..iii PREFACE………………………………………………………………………………….........iv DECLARATIONS 1- PLAGARISM…………………………………………………………...v DECLARATIONS 2- PUBLICATIONS…………………………………………………........vi ACKNOWLEDGEMENTS…………………………………………………………………...viii TABLE OF CONTENTS……………………………………………………………………….ix Chapter 1: Introduction……………………………………………………………………........1 1.1 Rationale for the research……………………………………………………………………..1 1.2 Justification…………………………………………………………………………………....3 1.3 Aims and Objectives of this study………………………………………………………….....7 1.4 Tables and Figures……………………………………………………………………….........8