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FACULTY OF SCIENCE

DOCTOR OF PHILOSOPHY (CHEMISTRY)

CANDIDATE: RAIDRON Celestine V

CURRICULUM VITAE

Celestine Raidron was born in the Khomas Region. She matriculated with
Exemption from the Holy Cross Convent, Windhoek. Her qualifications
include, Bachelor of Science; Post Graduate Diploma in Education, from
the University of Namibia; and Masters in Chemistry from Murdoch University,
Australia. Her professional career includes working as Technician and upgraded to Lecturer in the
Department of Chemistry at the University of Namibia, where she is currently employed. During a brief
interruption at UNAM, she worked as a teacher at the International School, EABJM, Lille, France, teaching
chemistry at the International Baccalaureate level. Her research interests include Organic and Natural
Product Chemistry.

CANDIDATE’S DISSERTATION

ANTITUBERCULAR AND ANTIMALARIAL ACTIVITY OF METABOLITES ISOLATED FROM CRUDE AND LEAD-LIKE
ENHANCED (LLE) EXTRACTS FROM SELECTED NAMIBIAN MEDICINAL PLANTS

The doctoral study was undertaken and completed under the supervision of Dr. Renate Hans of the
University of Namibia as Main-Supervisor and Dr. Suthananda Sunassee from the University of Cape Town
as Co-Supervisor.

Malaria and tuberculosis (TB) pose major health problems globally and of concern is the development of
resistance against clinically approved drugs. This increased the need to expeditiously find novel chemical
compounds and to enrich drug-discovery programs. Medicinal plants remain an important source of new
lead compounds and drugs, but the re-isolation of known compounds and the loss of bioactivity during
purification, when using classical methodologies, presents a major challenge for the discovery of novel
bioactive compounds. This study used a protocol developed by Camp and co-workers, which involved
enhancing the quality of plant extracts by frontloading them with metabolites that comply with drug-like
properties, that is, generating lead like enhanced (LLE) extracts. This study explored the antitubercular and
antimalarial activity of metabolites isolated from crude (organic and aqueous) and lead-like enhanced
(LLE) extracts from selected Namibian medicinal plants. The eight plant species selected for the study
are used traditionally by communities in Uis and Tsumkwe for the treatment of tuberculosis, malaria and
associated symptoms. The study found that Adansonia digitata, displayed the best antimycobacterial
and antiplasmodial activity. Correlation between the ethnobotanical uses with the biological results were
confirmed for all plants, except Sarcocaulon marlothii, an endemic, scientifically unexplored specie in
Namibia. It is used traditionally for treating TB, but the organic as well as aqueous extracts displayed good
antiplasmodial activity. In general, the LLE extracts displayed increased or equipotent antiplasmodial active
compared to the crude extracts, whereas none of the LLE extracts displayed antimycobacterial activity. This
study supports the enrichment of extracts to expedite antimalarial drug research and recommends further
purification of the crude and LLE extracts of S. marlothii, to unambiguously identify the active compound/s
which could serve as leads in antimalarial drug-discovery.

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