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Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans
Dissertation (MSc (Medicinal Plant Science))--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613501324787712 |
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| access_status_str | Open Access |
| author2 | Lall, Namrita |
| author_browse | Lall, Namrita |
| author_facet | Lall, Namrita |
| collection | Thesis |
| description | Dissertation (MSc (Medicinal Plant Science))--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110144 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:09.154Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110144 Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans Lall, Namrita dikonketsobodiba@gmail.com Crampton, Bridget Genevieve Bodiba, Dikonketso Heteropyxis Gene expression Synergism Antioxidants Dissertation (MSc (Medicinal Plant Science))--University of Pretoria, 2016. The successful establishment of diseases such as dental caries is highly dependent on the unique ability of the main causative agent, Streptococcus mutans to directly bind itself onto the enamel of the tooth. S.mutans is able to synthesise membrane bound enzymes such as AntigenI/II (encoded for by the spaP gene) and Glucotranferases (Gtf) (encoded for by the gtf genes) which use components found in the saliva as well as carbohydrates from food, to produce extracellular polysaccharides that aid in the attachment of the bacteria. There are currently no plants that have been reported to have a mechanism that specifically targets the expression of the virulence genes that encode for the above mentioned enzymes. Also, there are very few reports on compounds that have been shown to target these genes. The Heteropyxidaceae family has been reported in literature for their traditional use in the treatment of toothache. Thus the current study focused on determining the antibacterial activity of Heteropyxis canescens (H.c) and Heteropyxis dehniae (H.d) against Streptococcus mutans (ATCC 25175). Furthermore, the effect of the Heteropyxis canescens on the expression of the virulence genes spaP and gtfB was determined. The leaves and twigs were used to make ethanol extracts and a calorimetric micro-dilution method was used to determine the minimum inhibitory concentrations (MICs) of the plant samples. Heteropyxis dehniae had an MIC of 1.56 mg/ml while Heteropyxis canescens had an MIC of 0.29 mg/ml. A combination of H.d and H.c resulted in a four-fold reduction of the MIC value for both H.c and H.d. The plant samples showed moderate toxicity against Vero cells. The antioxidant potential was also determined and found to be comparative to all the positive controls. This indicated an indirect mechanism of the plants against the bacteria that involved reducing the oxidative damage that is inflicted on host cells by the bacteria. Total RNA was extracted from untreated and H.c extract treated cells. H.c was chosen for this part of the study because it had the best antibacterial activity. cDNA was synthesized from cells treated with 0.5 mg/ml extract and was used to conduct RT-PCR. The plant sample not only showed a mechanism of action through antioxidant activity, but mRNA inhibition as well. The expression levels of the spaP gene were significantly reduced in treated cells (p0.01; relative to the reference gene glnA. The results from the current study suggest a mechanism of action that specifically targets attachment of S.mutans through AntigenI/II, at a transcription level. The leaves and twigs of Heteropyxis canescens were also used to conduct column chromatography for possible isolation of novel compounds. The study did not produce any pure compounds, however there were two sub-fractions that showed promising results and will be a target for further isolations in the future. Plant Science MSc (Medicinal Plant Science) 2026-05-15T17:26:26Z 2026-05-15T17:26:26Z 17/02/06 2016 Dissertation http://hdl.handle.net/2263/110144 en application/pdf |
| spellingShingle | Heteropyxis Gene expression Synergism Antioxidants Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title | Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title_full | Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title_fullStr | Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title_full_unstemmed | Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title_short | Biological activity of Heteropyxis and its mechanisms against Streptococcus mutans |
| title_sort | biological activity of heteropyxis and its mechanisms against streptococcus mutans |
| topic | Heteropyxis Gene expression Synergism Antioxidants |
| url | http://hdl.handle.net/2263/110144 |