BACKGROUND: Lannea schweinfurthii, Zanthoxylum capense, Scadoxus puniceus and Crinum bulbispermum are used
traditionally to treat neurological disorders. The aim of this study was to evaluate the cytoprotective potential of the
four plants, after induction of toxicity using rotenone, in SH-SY5Y neuroblastoma cells.
METHODS: Cytotoxicity of the plant extracts and rotenone was assessed using the sulforhodamine B (SRB) assay.
Fluorometry was used to measure intracellular redox state (reactive oxygen species (ROS) and intracellular glutathione
content), mitochondrial membrane potential (MMP) and caspase-3 activity, as a marker of apoptotic cell death.
RESULTS : Of the tested plants, the methanol extract of Z. capense was the least cytotoxic; LC50 121.3 ± 6.97 μg/ml, while
S. puniceus methanol extract was the most cytotoxic; LC50 20.75 ± 1.47 μg/ml. Rotenone reduced intracellular ROS levels
after 24 h exposure. Pre-treating cells with S. puniceus and C. bulbispermum extracts reversed the effects of rotenone on
intracellular ROS levels. Rotenone exposure also decreased intracellular glutathione levels, which was counteracted by
pre-treatment with any one of the extracts. MMP was reduced by rotenone, which was neutralized by pre-treatment
with C. bulbispermum ethyl acetate extract. All extracts inhibited rotenone-induced activation of caspase-3.
CONCLUSION : The studied plants demonstrated anti-apoptotic activity and restored intracellular glutathione content
following rotenone treatment, suggesting that they may possess neuroprotective properties.