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Modulation of high glucose-induced oxidative stress using cannabis sativa plant extracts in HEPG2 cells
Author(s)
Africa, Anevay Anbren
Date Issued
2026
Type
master thesis
Publisher
Cape Peninsula University of Technology
Abstract
Diabetes mellitus (DM) has become a major concern globally within the healthcare community, due to its prevalence and related complications. Type 2 diabetes mellitus (T2DM) is a metabolic disorder mainly characterised by hyperglycaemia. Hyperglycaemia can lead to oxidative stress (OS), caused by excessive generation of reactive oxygen species (ROS), which may result in the impairment of the antioxidant (AO) defense system. OS is known as one of the points of origin of diabetic complications. Cannabis sativa is a medicinal plant known to contain a variety of secondary metabolites such as phytocannabinoids and have become increasingly popular among patients who self-medicate. C. sativa is used traditionally in many parts of the world to alleviate the symptoms of various chronic illnesses. One of the cannabinoids, cannabidiol (CBD), has been known to exhibit antioxidant, anti-inflammatory and hepatoprotective properties. The number of patients using cannabis as a treatment for various health conditions is growing worldwide, it is imperative for further scientific research to be done which focuses on the selection, identification, and characterisation of the bioactive compounds. Current knowledge on extraction methods is insufficient and studies focusing on this field have been neglected. The hepatoprotective role of acetone, ethanolic and aqueous C. sativa extracts were evaluated in this study using an in vitro glucotoxic model, to address the limited knowledge on the effectiveness of different cannabinoid extraction methods against oxidative stress. The phytochemical composition of the extracts used in this study were determined by the liquid chromatography/mass spectrometry (LC/MS) method. The resulting phytochemical fingerprint revealed compounds typical of cannabis, including well characterised phytocannabinoids: cannabidiol (CBD), and tetrahydrocannabinol (THC), which were identified as the primary constituents in the isolates. The total antioxidant (AO) content of C. sativa extracts showed an increase that was dependent on the dosage. The antioxidant capacity was evaluated in cellfree systems using three methods: total polyphenol content (TPC), the 2,2-diphenyl-1picrylhydrazyl (DPPH) assay, and the ferric ion reducing antioxidant power (FRAP) assay. The biological effects of Cannabis sativa extracts on cell viability, metabolic activity, oxidative damage, and cellular death under hyperglycaemic (HG) conditions were assessed. After treating HepG2 cells for 24 hours, cell viability and metabolic activity were assessed using the MTT ([3-4,5-Dimethylthiazol-2-yl)-2.5-Diphenyltetrazolium Bromide]) and intracellular adenosine triphosphate (ATP) assays. Oxidative damage was measured through the thiobarbituric acid reactive substance (TBARS) assay, while redox status was evaluated using the reduced glutathione (GSH) assay. Cellular death was assessed via lactate dehydrogenase (LDH), caspase-8, and caspase-9 assays. Results indicated that treatment with the C. sativa aqueous extract significantly elevated ATP levels (p < 0.0001) at a concentration of 200 µg/mL compared to the HG control, demonstrating its protective effect. While the aqueous extract preserved cell viability at lower concentrations (0-600 µg/mL), the acetone and ethanolic extracts demonstrated a dose-dependent decrease in cell viability. Additionally, both the ethanol and aqueous extracts significantly (p < 0.0001) increased GSH concentrations compared to the HG control, with notable increase observed at 35 and 50 µg/mL for the ethanol extract and at 200 and 370 µg/mL for the aqueous extract. A significant decrease in caspase-8 activity was noted at 100 µg/mL of the acetone extract, while the highest concentration (600 µg/mL) of the aqueous extract significantly reduced caspase-8 activity. Moreover, both the acetone and ethanolic extracts showed a significant decrease in caspase-9 activity at their respective high concentrations (100 µg/mL and 50 µg/mL). The current study demonstrates that Cannabis sativa, a well-known and widely used medicinal plant, at certain concentrations, may enhance the endogenous antioxidant defence system in The human liver cell line (HepG2) cells experiencing HG-induced oxidative stress. This enhancement is not true for all extracts and concentrations tested in this model, leading to the conclusion that different C. sativa extracts can potentially exhibit pro-oxidant (toxic) properties at certain concentrations. However, the findings of this study suggest the prospective use of C. sativa extracts in preventative and therapeutic strategies against metabolic disorders such as hyperglycaemia and DM. The results obtained in this study indicate that the aqueous C. sativa extract performed the best at the concentration of 200 µg/mL in the assays and showed to be less toxic to the HepG2 cells when compared to the acetone and ethanolic extracts. Further investigation into the mechanisms involved in the protective effects of the aqueous C. sativa extract need to be conducted.
Additional information
Thesis (MSc (Biomedical Technology))--Cape Peninsula University of Technology, 2026
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