Page 23 - 7-Windhoek MORNING SESSION e-BOOK (27 April 2023)

School of Science
FACULTY OF AGRICULTURE,
ENGINEERING & NATURAL SCIENCES

DOCTOR OF PHILOSOPHY IN SCIENCE
(APPLIED BIOLOGICAL SCIENCES)

CANDIDATE: SHATRI Albertina M

CANDIDATE’S DISSERTATION

DESIGNING AND CHARACTERIZING THE PLANT-
BASED CHITOSAN-MODIFIED POLY (LACTIC-CO-
GLYCOLIC ACID) NANOPARTICLES FOR SALMONELLA AND E. COLI-INDUCED
GASTROENTERITIS.

The doctoral study was undertaken and completed under the
supervision of Prof Davis R Mumbengegwi from the University of
Namibia and Co-Supervised by Dr. Yolandy Lemmer from the Council
of Scientific & Industrial Research (CSIR), South Africa.

The candidate documented and validated the ethnomedicinal
uses of medicinal plants in the Omusati region and developed 5
novel plant-based chitosan-modified poly (lactic-co-glycolic acid)
nanoparticles (CMPLGA) for treating multidrug-resistant Salmonella
and E. coli-induced gastroenteritis.
The study documented the use of 19 plant species used locally to
treat gastroenteritis in the Omusati region. This study also validated
the phytochemical composition, efficacy, and cytotoxicity of
the 4 commonly used plants in the region namely Grewia tenax
(Oshishegele), Terminalia sericea (Omugolo), Lantana camara (Iikulya
yaanahambo), and Corchorus tridens (Okaliipute). The study is also
the first of its kind to design CMPLGA nanoparticles (prototypes) for
stable plant-based alternative treatments for gastroenteritis. The study
revealed that the use of nanoparticles as carriers of plant-based
medicine does enhance the efficacy, safety, and physicochemical
as well as in vitro release properties of plant-based medicine. All
these properties help to overcome challenges associated with the
oral delivery of phytomedicine within the gastrointestinal tract by
improving the bioavailability, biocompatibility, payload, and retention
within the gastrointestinal tract while ensuring controlled release at the
targeted site. The study further validated the use of lyophilization as a
preservation method for plant-based nanoparticles to improve shelf
life and provides Namibian policymakers with useful information on the
potential of medicinal plants as sources of alternative /complementary
medicine for gastroenteritis.

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