Year: 2012
Type: dissertation
Abstract: Studies have shown that the traditional healers have used Tulbaghia violacea (TV) (also \nknown as ‘wild garlic’) for the treatment of a number of ailments including fever, \ntuberculosis, stomach problems, and oesophageal cancer. However, little is known with \nregards to the anticancer and antiproliferative properties of this plant. Therefore, this \nstudy investigated the effects of TV and domesticated garlic extracts on Jurkat cells, in \norder to determine whether or not these extracts possess anti-proliferative properties. \nCultured Jurkat cells were treated with IC50 concentrations of garlic (14μg/ml), TV leaf \n(256μg/ml), TV bulb (225μg/ml) and TV stalk (216μg/ml) extracts as determined by the \nmethylthiazol tetrazolium assay. Free radical production was measured using the \nthiobarbituric acid reactive substance (TBARS) and nitric oxide (NO) assays, while \nglutathione (GSH) concentration was measured using the GSH-Glo™ assay. The \napoptosis inducing properties of each extract were measured using flow cytometry \n(Annexin V- Fluos and JC-1 assays) and luminometry (caspases 3/7, 8, 9 and ATP). \nWestern blots were run to determine protein expression, while comet and DNA \nfragmentation assays were used to determine the level of DNA damage induced. Wild \nand domesticated garlic extracts induced a significant increase in malondialdehyde \nconcentration ([MDA]), with TV bulb extract inducing the highest concentration \n(p<0.0001). A significant increase in NO concentration was observed in the bulb \n(p<0.0001) and stalk (p<0.001) extracts, and leaf (p<0.05) and stalk (p<0.05) TV \nextracts significantly increasing GSH concentration. The longest comet tails were \nobserved in TV bulb extracts (p<0.0001) and comprised mainly of single strand breaks, \nwhile the comets induced following garlic exposure contained double strand breaks. All \nextracts, except TV leaf, increased the percentage of cells undergoing apoptosis. \nTulbaghia violacea leaf induced a significant (p<0.0001) increase in percentage of cells \nundergoing necrosis, whereas TV bulb resulted in a significant (p<0.0001) decrease. \nAll TV extracts induced caspase 3/7 and 9 activity, with the most significant increase in \ncaspase 9 activity observed for TV leaf and bulb. No significant change in caspase 3/7 \nactivity was evident for domesticated garlic. Cleavage of PARP and expression of \nNF B and HSP 70 occured for all extracts. However, HSP 70 was not differentially \nexpressed. Exposure to wild and domesticated garlic extracts induced peroxidative lipid \nand DNA damage within the cells, indicating oxidative stress. This damage occurred in \nconjunction with increased percentage of cells undergoing apoptosis and expression of \ncaspase 3/7. Therefore, these findings suggest that TV is inducing cell death through \napoptosis in Jurkat cells using a number of mechanisms, including the induction of \noxidative stress. This is of clinical significance, as cell death through apoptosis is the \npreferred method of action for anti-cancer drugs.
Author: Jared S. Mackenzie
Language: English
Topic: Garlic and Onion Studies
Subfield: Plant Science
Domain: Life Sciences
Open Access status: green
Funder: National Research Foundation
OpenAlex ID: W1554384531