Terminalia ivorensis (TI) is a tree found in the tropical and sub-tropical zones of the world. It is used in ethnomedicine for the treatment of diuresis, body pains, malaria and wound healing. There are no data investigating the impact of TI on human liver cells and cancer. Cancer is a global health problem causing an estimated 10 million deaths worldwide in 2020. Chemotherapy and radiotherapy are the commonly used methods for the management of cancer but are associated with severe side effects such as anxiety, bleeding, depression, heart problems, perforated gut and secondary cancers. The aim of this study was to determine the influence of solvent, season and storage time on the phytochemical profile of TI, and to search for potential safer treatment options for cancer by determining the impact of TI on biomarkers of cyto- and genotoxicity in human colon and liver cells in vitro. Fresh TI samples were collected in the dry and rainy seasons from Asakakra Kwahu, Eastern region of Ghana, and a TI sample that had been stored at room temperature for 4 years was also used. The phytochemicals were isolated either by sequential Soxhlet extraction using petroleum ether, chloroform, ethyl acetate and ethanol, or by water extraction and were identified by liquid chromatography/mass spectroscopy. The study also measured the effect of TI extracts on human colon and liver cells. This was carried out using assays for drug metabolising enzymes (DME), such as cytochrome P450, catalase, glutathione peroxidase (GPx), glutathione reductase (GSR) and reduced glutathione (GSH) - an essential tripeptide for drug metabolism. Cell viability was measured by the methyl thiazol tetrazolium bromide assay, cell proliferation by cell counting, DNA damage and DNA repair by single cell gel electrophoresis, and cell migration using the radial migration assay. It was found that the chemical extraction procedure was consistent and robust for carrying out the study, as it yielded comparable and consistent phytochemicals from different batches of extractions. Moreover, the phytochemicals isolated and identified from TI were significantly dependent on the solvent, season and storage. It was also found that different extracts of TI showed differential activity on hepatic DME activities in human liver cells in vitro. Chloroform extract significantly (p < 0.05) inhibited the activities of cytochrome P450, GSH, GPx and GSR. In contrast, ethanol extract significantly (p < 0.05) induced the activities of cytochrome P450, catalase, GSH, GPx and GSR. TI was more toxic in human colon cells (either normal or cancerous) than in liver cells. It also showed potential anticancer effects by affecting some hallmarks of cancer, including cell viability and proliferation, DNA damage, DNA repair and cell migration. Ethyl acetate and ethanol extracts were selectively more toxic in human colon cancer cells than in non-malignant colon cells. The impact of TI on human liver cells and anticancer properties shown by TI extracts were possibly due to the different phytochemicals present in the extracts, therefore further work is required to isolate the active compounds and test for the potential anticancer effects.
MOOMIN, A. 2021. Terminalia ivorensis and human health: the impact of Terminalia ivorensis on biomarkers of cyto- and genotoxicity in human cells in vitro. Robert Gordon University, PhD thesis. Hosted on OpenAIR [online]. Available from: https://doi.org/10.48526/rgu-wt-1603185