Browsing by Author "Ekpo, Okobi"
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Item Antioxidant and apoptosis-inhibition potential of Carpobrotus edulis in a model of parkinson’s disease(African Association of Physiological Sciences, 2018) Enogieru, A.B.; Omoruyi, S.I.; Ekpo, OkobiBackground: Parkinson’s disease (PD) is a neurological disorder resulting from the progressive loss of dopaminergic neurons. There is currently no known cure for PD, thus the search for complementary and alternative medicines capable of halting the degeneration of dopaminergic neurons is plausible. Carpobrotus edulis (CE) is an indigenous plant used in South African traditional medicine used for the treatment of a number of disease conditions including tuberculosis, diabetes mellitus and constipation. It has been suggested that CE contains bioactive compounds which are responsible for its acclaimed medicinal potential. No studies have been reported on the potential benefit of CE to the nervous system. This study was therefore done to evaluate the protective effects of CE against 1-methyl-4-phenylpyridinium (MPP+)-induced toxicity in the dopaminergic SH-SY5Y cell line, as well as its underlying mechanism. Methods: In this study, SH-SY5Y cells were treated with varying concentrations of CE and MPP+ respectively to determine the optimal concentrations of MPP+ and CE for further experiments. Thereafter, SH-SY5Y cells were pre-treated with 30 μM of CE before exposure to 2 mM of MPP+ to induce cellular damage. Cell viability was evaluated using the MTT assay, intracellular reactive oxygen species (ROS) production was determined using flow cytometry and the Hoechst nuclear staining was used to visualize apoptosis. Caspases 3/7 and 9 activity was assessed using commercially available kits. Results: MPP+ treatment induced marked cell viability, increased the number of condensed nuclei and apoptotic cells, increased ROS production, initiated caspase 9 and activated caspase 3/7 in SH-SY5Y cells. The observed effects of MPP+-induced toxicity were attenuated by the pre-treatment of SH-SY5Y cells with 30 μM of CE. Conclusion: The protective effects of CE against MPP+-induced toxicity in SH-SY5Y cells may be attributed to its antioxidant and anti-apoptotic properties.Item The development of functionalized metallic nanoparticles for the treatment of brain cancer(University of the Western Cape, 2019) Fipaza, Vincent Lukhanyiso; Ekpo, OkobiCancers of the nervous system often result from abnormal and uncontrolled growth of cells in nervous tissue. Glioblastoma Multiforme (GBM) and neuroblastoma (NB) are among the most common nervous system-associated cancers known to be relatively difficult to treat. GBM is an aggressive cancer in adults while NB mostly develops in infants and children younger than five years old. Current chemotherapeutic treatment options for GBM and NB have a number of drawbacks, including non-specific toxicity, drug resistance and the inability to cross the blood-brain barrier (BBB). Therefore, there is a need to develop new treatment options that can cross the BBB with minimal or no side effects to normal neural tissues. Gold (Au) and platinum (Pt) nanoparticles (NPs) have been shown to play a role in drug delivery by crossing the BBB to selectively target cancer tissue. However, these metallic nanoparticles have a short life span in the circulatory system and often elicit immune reactions. The functionalization of nanoparticles with polyethylene glycol (PEG) helps to improve their stability and biocompatibility. The aim of this study was therefore to develop PEGylated metallic nanoparticles and investigate their potential in vitro cytotoxic effects on SH SY5Y (NB) and U87 (GBM) cell lines.Item Differential sensitivity of two endothelial cell lines to hydrogen peroxide toxicity: Relevance for in vitro studies of the blood–brain barrier(MPDI, 2020) Alamu, Olufemi; Rado, Mariam; Ekpo, OkobiOxidative stress (OS) has been linked to blood–brain barrier (BBB) dysfunction which in turn has been implicated in the initiation and propagation of some neurological diseases. In this study, we profiled, for the first time, two endothelioma cell lines of mouse brain origin, commonly used as in vitro models of the blood–brain barrier, for their resistance against oxidative stress using viability measures and glutathione contents as markers. OS was induced by exposing cultured cells to varying concentrations of hydrogen peroxide and fluorescence microscopy/spectrometry was used to detect and estimate cellular glutathione contents. A colorimetric viability assay was used to determine changes in the viability of OS-exposed cells. Both the b.End5 and bEnd.3 cell lines investigated showed demonstrable content of glutathione with a statistically insignificant difference in glutathione quantity per unit cell, but with a statistically significant higher capacity for the b.End5 cell line for de novo glutathione synthesis. Furthermore, the b.End5 cells demonstrated greater oxidant buffering capacity to higher concentrations of hydrogen peroxide than the bEnd.3 cells. We concluded that mouse brain endothelial cells, derived from different types of cell lines, differ enormously in their antioxidant characteristics. We hereby recommend caution in making comparisons across BBB models utilizing distinctly different cell lines and require further prerequisites to ensure that in vitro BBB models involving these cell lines are reliable and reproducible.Item Neuroprotective Activities of Crossyne flava Bulbs and Amaryllidaceae Alkaloids: Implications for Parkinson’s Disease(MDPI, 2021) Ibrakaw, Abobaker; Omoruyi, Sylvester; Ekpo, OkobiParkinson’s disease (PD) is one of the most common neurodegenerative diseases and affects approximately 6.3 million people worldwide. To date, the treatment of PD remains a challenge, as available treatment options are known to be associated with serious side effects; hence, the search for new treatment strategies is critical. Extracts from the Amaryllidaceae plant family as well as their alkaloids have been reported to have neuroprotective potentials. This study, therefore, investigated the biological activities of Crossyne flava and its isolated alkaloids in an in vitro MPP+(1-methyl-4- phenylpyridinium) PD model using SH-SY5Y cells. The effects of the total extract as well as the four compounds isolated from Crossyne flava (i.e., pancratinine B (1), bufanidrine (2), buphanisine (3), and epibuphanisine (4)) were evaluated for cell viability, neuroprotection, levels of reactive oxygen species (ROS), adenosine triphosphate activity (ATP), and caspase 3/7 activity in SH-SY5Y cells. The results obtained showed that pre-treatment with both the extract and the isolated compounds was effective in protecting the SH-SY5Y cells from MPP+ -induced neurotoxicity and inhibited ROS generation, ATP depletion as well as apoptosis induction in the SH-SY5Y cells. The results of this study show that the Amaryllidaceae plant family may be a source of novel compounds for the treatment of neurodegenerative diseases, which validates the reported traditional uses.Item Neuroprotective activities of crossyne flava bulbs and amaryllidaceae alkaloids: Implications for parkinson’s disease(Molecules, 2021) Omoruyi, Sylvester; Ibrakaw, Abobaker; Ekpo, Okobi; Boatwright, JamesParkinson’s disease (PD) is one of the most common neurodegenerative diseases and affects approximately 6.3 million people worldwide. To date, the treatment of PD remains a challenge, as available treatment options are known to be associated with serious side effects; hence, the search for new treatment strategies is critical. Extracts from the Amaryllidaceae plant family as well as their alkaloids have been reported to have neuroprotective potentials. This study, therefore, investigated the biological activities of Crossyne flava and its isolated alkaloids in an in vitro MPP+ (1-methyl-4- phenylpyridinium) PD model using SH-SY5Y cells. The effects of the total extract as well as the four compounds isolated from Crossyne flava (i.e., pancratinine B (1), bufanidrine (2), buphanisine (3), and epibuphanisine (4)) were evaluated for cell viability, neuroprotection, levels of reactive oxygen species (ROS), adenosine triphosphate activity (ATP), and caspase 3/7 activity in SH-SY5Y cells. The results obtained showed that pre-treatment with both the extract and the isolated compounds was effective in protecting the SH-SY5Y cells from MPP+-induced neurotoxicity and inhibited ROS generation, ATP depletion as well as apoptosis induction in the SH-SY5Y cells. The results of this study show that the Amaryllidaceae plant family may be a source of novel compounds for the treatment of neurodegenerative diseases, which validates the reported traditional uses.Item Sleep deprivation and neurological disorders(Hindawi, 2020) Ekpo, Okobi; Bishir, Muhammed; Bhat, AbidSleep plays an important role in maintaining neuronal circuitry, signalling and helps maintain overall health and wellbeing. Sleep deprivation (SD) disturbs the circadian physiology and exerts a negative impact on brain and behavioural functions. SD impairs the cellular clearance of misfolded neurotoxin proteins like α-synuclein, amyloid-β, and tau which are involved in major neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. In addition, SD is also shown to affect the glymphatic system, a glial-dependent metabolic waste clearance pathway, causing accumulation of misfolded faulty proteins in synaptic compartments resulting in cognitive decline. Also, SD affects the immunological and redox system resulting in neuroinflammation and oxidative stress. Hence, it is important to understand the molecular and biochemical alterations that are the causative factors leading to these pathophysiological effects on the neuronal system. This review is an attempt in this direction. It provides up-to-date information on the alterations in the key processes, pathways, and proteins that are negatively affected by SD and become reasons for neurological disorders over a prolonged period of time, if left unattended.Item Synthesis, characterization and anticancer effects of quantum dots in neuroblastoma and glioblastoma cell lines(University of the Western Cape, 2018) Lasher, Sashca Yosima; Ekpo, OkobiIntroduction: Nanoparticles (NPs) are gaining increased popularity for cancer treatment, especially the multifunctional nanoparticles like Quantum dots (QDs) which have a wide range of applications in nanotheranostics, cell imaging and targeted drug delivery to cancerous tissue. QDs comprise of very tiny crystals of a semiconductor material (diameter: 2-10 nm) capable of producing bright, intensive and size-tuneable near-infrared fluorescence emissions. In particular, 3-mercaptopropionic acid -capped Cadmium Telluride Quantum Dots with a zinc sulphide shell (MPA-capped CdTe/ZnS QDs), are known to be very stable, highly photoluminescent, less toxic with long-lasting “fluorophore” effects, thus making them the preferred QDs for this study. Aims: To synthesize and characterize biocompatible MPA-capped CdTe/ZnS QDs to determine size range, polydispersity index (PdI), zeta (ζ) potential, photoluminescence (PL) spectra, stability in various milieus as well as to evaluate the effects of the synthesized QDs on the viability and morphology of neuroblastoma (NB) and glioblastoma (GB) cell lines using the WST-1 cell viability assay, imaging and cell cycle analysis. Materials and methods: MPA-capped CdTe/ZnS QDs were synthesized and analysed with the Zetasizer to determine ζ-potential, hydrodynamic (hd) size and PdI, while high resolutiontransmission electron microscopy (HR-TEM) was used to validate the hd size and elemental composition using energy dispersive X-ray (EDX) spectra. Pl absorption and emission spectra were obtained with a fluorometer and stability studies were done using UV-Vis spectroscopy, permitting further biological evaluation. A concentration range of 5-20μg/ml QDs was exposed to U87 and SH-SY5Y cancer cell lines to determine biological effects at different time points, using the WST-1 assay. Confocal fluorescence microscopy was used to establish uptake and cellular localization of the QDs, cell morphology was visualized with an inverted microscope while cell cycle distribution analysis was done using the C6 flow cytometer.