The natural product chemistry research group focuses on adding value to South Africa's wealth of biological resources and indigenous knowledge through scientific innovation. This includes identifying potential new pharmaceutical, food ingredients and cosmeceutical ingredients biodiversity and Indigenous Knowledge based on the use of medicinal plants. The research groups build on the three important pillars of Bioprospecting which is Biodiversity, Traditional Knowledge and scientific innovation.
The key focus of the group is to scientifically research and identify natural compounds and herbal extracts based on traditional medicines aimed at the discovery of early-stage leads for the pharmaceutical, food and cosmetic industries and their further development to Proof of Concept.
The Bioprospecting group manages a comprehensive bioprospecting science and technology value chain to include gathering of indigenous knowledge and biodiversity samples, extraction and biological evaluation of samples, bioassay-guided isolation, characterization of new biologically active molecules, research and development of minimally processed herbal remedies (botanical extracts) and their production in compliance. A major emphasis is placed on the development of lead compounds and herbal treatments in search for solutions to some of Africa's major diseases: HIV/Aids, malaria and TB.
Due to the wide scope of the science and technology platforms required to undertake bioprospecting, access to certain platforms is managed through consortium based research e.g. plant taxonomy (S A National Biodiversity Institute and University of Pretoria Herbarium); biological assays relevant to malaria (UP Department of Biochemistry), HIV (University of Basel, Switzerland and CSIR), diabetes (SA Medical Research Council), cancer (CSIR and University of Pretoria), Alzheimer’s disease (Korean Institute for Science and Technology) and inflammation (JSS University, India and Zhejiang University, China) and high end natural product chemistry structure elucidation (University of Wuerzburg, Germany) using hyphenated HPLC MS SPE NMR.
Much of this group's research involves collaboration between a multidisciplinary team of scientists of discovery biologists for drug and target identification and validation, a systems biology approach to elucidate the mechanism(s) of action of traditional medicines, elucidation of new molecular scaffolds and lead molecule optimization with discovery chemists within the chemistry department research groups. Results from this group have contributed towards the establishment of poverty alleviation initiatives where communities are offered an opportunity to participate in the production of biomass through community-based cultivation and processing of indigenous plants.
Natural anti-malarial lead discovery
This project investigates the tropical lianas of the Ancistrocladaceae family for their potential anti-malarial alkaloids. It aims at isolating bioactive naphthylisoquinoline alkaloids targeting the asexual parasites, early and late gametocyte stages of Plasmodium falciparum.
Figure 1: A recently collected Ancistrocladus plant (private photo).
Collaborator: Prof G. Bringmann, University of Wuerzburg, Germany.
Students: Félix Katele Zongwe (PhD), Sephora Mianda Mutombo (MSc).
Natural lead compounds for Alzheimer’s disease
The project focuses on identifying, characterizing and developing new natural ingredients from the South African traditional plants for the treatment of Alzheimer’s disease. The aim is to isolate bioactive molecules targeting the amyloid plaques, the hallmark of Alzheimer’s disease by the reduction of Aβ42.
Collaborator: Korea Institute of Science and Technology (KIST)
Student: Anuradha (PhD)
Anti HIV lead discovery
The anti-HIV project studies South African medicinal plants used by local traditional healers as cure in the treatment of HIV. The objective is to isolate lead compounds and monitor their potential as inhibitors in the stages of the replication cycle of HIV.
Figure 2: One of the plant under investigation.
Collaborators: Prof. T. Klimkait (University of Basel, Switzerland) and the CSIR.
Students: Babalwa Tembeni (PhD) and Phindiwe Felicia Chawuke (PhD)
The aim is to develop nutraceuticals from local plants using green technologies. The project includes isolation of active ingredients, their validation for potential health benefits and micro-encapsulation in cyclodextrins towards improving their physicochemical properties.
Collaborators: Nomusa Dlamini, Biosciences, CSIR, Brummeria Philip Labuschagne, Materials and Manufacturing, CSIR.
Student: Buntubonke Mzondo (PhD)
Natural anti-aging ingredients
The project aims to develop new anti-aging ingredients from indigenous plants, targeting inhibition of the elastase and collagenase enzymes, and growth promotion of elastin and collagen. The study bio-assays plant extracts for their anti-aging activity, the most active extracts are fractionated and active fractions are targeted for purification of their active metabolites. The objective is to formulate the bioactive extracts, fractions and pure compounds into anti-aging cosmeceuticals, such as day cream and a night cream for extensive clinical trials.
Student: Tinotenda Shoko (PhD)
Natural ingredients as anti-inflammatory agents
Monsonia plants are studied as a potential source of anti-inflammatory natural products, using Nrf2 and in-vitro scratch healing assays. The investigation, which involves a bio-guided fractionation, consists in identifying the most active fractions of the plant extracts, followed by the isolation of active ingredients and elucidation of their molecular structures. The overall goal is to develop stable herbal formulations from the active extracts and/or fractions.
Collaborators: Dr. Dashnie Naidoo and Dr. Sieglinde Bauermeister, Department of Chemistry, University of Pretoria. Dr Rajesh Kumar JSS University, India
Student: Séverin Muyisa Kavatsurwa (PhD)
Anti-inflammatory properties of African ginger
Siphonochilus aethiopicus (African ginger) is widely used by traditional healers to treat colds, flu, coughs, sinus problems, asthma, etc. The project focuses on African ginger to produce a stable form of the volatile components of the rhizomes and roots and to scientifically evaluate its traditional use so that it can be formulated as an inhalant for commercial purposes.
Student: Leylene Kruger (MSc)
Natural anti-cancer lead compounds
The project aims at identifying potential antineoplastic agents from South African medicinal plants. Cytotoxicity of extracts and isolated compounds is evaluated on various cancer cell lines and modes of action determined.
Collaborators: Dr André Stander, University of Pretoria
Student names: Tshifhiwa Ramabulana (PhD)
Bioactive Phenolic Compounds as Anti-microbial, Anti-oxidant and Anti-cancer agents (PhD)
Phenolic compounds are common in many plants and exhibit a wide range of physiological properties, such as anti-oxidant, anti-microbial, anticancer. This project aims to validate the properties of three medicinal plants used in folk medicine which demonstrate biological activities for the treatment of microbial and oxidative stress diseases. Phytochemical investigation and biological evaluation of the crude material, fractions and pure isolated compounds will allow us to obtain molecules which could be used as lead compounds in order to obtain novel potential antimicrobial, antioxidant and anticancer drugs candidates.
Collaborators: Dr N October, Department of Chemistry, University of Pretoria; Prof D E Pegnyemb, Department of Organic Chemistry, University of Yaoundé I, Cameroon
Student: Marius Missi Balemaken (PhD)
Prof VJ Maharaj
Dr Natasha October
Dr Mamoalosi Selepe
Dr Bongiwe Mshengu