Aflatoxin B1 (AFB1), a potent hepatotoxic and hepatocarcinogenic mycotoxin synthesised by
toxigenic fungi (Aspergillus flavus and Aspergillus parasiticus), is a common contaminant of
many cereal commodities consequently posing a major threat to human and animal health.
Sutherlandia frutescens (SF), a traditional medicinal plant endemic to Southern Africa, is
commonly used by many cultures as a tonic for various health-related conditions. Incidentally,
the present study aimed at investigating the potential hepatoprotective capacity of SF and L-canavanine
(L-can, a major constituent of SF) against AFB1-induced cytotoxicity in human
HepG2 cells and used a standard treatment procedure of 24 h. Cell viability was evaluated
using the methyl thiazol tetrazolium (MIT) assay, which effectively demonstrated the ability
of SF, when administered individually and in combination with AFB1, to be significantly
cytotoxic to HepG2 cells in a dose-dependant manner. Reactive oxygen species (ROS) and
consequent peroxidative damage caused by AFB1 are considered to be the main mechanisms
leading to hepatotoxicity and was confirmed by the thiobarbituric acid reactive substances
(TBARS) assay which revealed that AFB1 mediated a significant increase in lipid peroxidation.
Additionally, comet assay analysis demonstrated the most pronounced effect to be observed
following administration of AFB1. In contrast, AFB1-mediated genotoxicity was significantly
reduced by SF and L-can. Such amelioration can be attributed to the marked increases in
glutathione (OSH) levels observed after the co-administration of SF and L-can with AFB1.
Cytoprotection by SF and L-can against AFB1-induced toxicity was further substantiated by
the significant increases in heat shock protein 70 expression. Moreover, when SF and L-can
were co-administered along with AFB1, analysis by flow cytometry revealed that AFB1 induced
increases in apoptosis and necrosis were reduced. The findings of this study propose
that SF and L-can may be selectively effective in alleviating AFB1-induced cytotoxicity and
lends pharmacological credibility to the suggested ethnomedical uses of SF. However, the
exact mechanism of action and the extracts efficacy in humans requires further authentication. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2008.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/8620 |
| Date | January 2008 |
| Creators | Pillay, Evashin. |
| Contributors | Chuturgoon, Anil A. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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