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The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants
Dissertation (MSc (Medicinal Plant Sciences))--University of Pretoria, 2018.
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| Language: | English |
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University of Pretoria
2026
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| _version_ | 1869484041673113600 |
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| access_status_str | Open Access |
| author2 | Lall, Namrita |
| author_browse | Lall, Namrita |
| author_facet | Lall, Namrita |
| collection | Thesis |
| dc_rights_str_mv | © 2025 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Medicinal Plant Sciences))--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110797 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-07-01T04:08:35.474Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110797 The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants Lall, Namrita kaykays@gmail.com Szuman, Karina Mariam UCTD Wetland plants Aquatic plants Therapeutic and medicinal potential Medicinal Plant Sciences South African aquatic and wetland plants Dissertation (MSc (Medicinal Plant Sciences))--University of Pretoria, 2018. Freshwater aquatic and wetland plants have for a large respect been understudied in terms of their medicinal value. Although terrestrial ecosystems are abundant and rich in species diversity, the lack of ethnobotanical studies carried out on freshwater aquatic and wetland ecosystems has impacted the vast potential of natural resources which South Africans could be utilising for therapeutic purposes. From an in-depth literature review on fifty indigenous South African wetland plants, twenty plants were evaluated for their antibacterial (against Propionibacterium acnes, Prevotella intermedia, Streptococcus mutans) and enzymatic inhibitory (against tyrosinase) potential. All these components are associated with common human ailments affecting people across the globe. P. acnes is involved in the pathogenesis of acne vulgaris while P. intermedia and S. mutans are oral pathogens involved in the onset of periodontitis and dental caries, respectively. Tyrosinase is the rate limiting enzyme involved in melanin production and may cause skin hyperpigmentation when overproduced. Ethanolic extracts of the selected plants were investigated for their antibacterial and anti-tyrosinase activity. Antibacterial activities were evaluated on P. acnes (ATCC 6919) and oral pathogens (S. mutans ATCC 25175 and P. intermedia ATCC 25611) using the PestoBlue colorimetric assays and compared with the positive controls tetracycline (an antibiotic) and chlorohexidine (an antibacterial agent), respectively. Anti-tyrosinase assays were performed and the concentration at which fifty percent of the enzyme is inhibited (IC50) of each species was determined by analysing the photometric results using Graph Pad Prism 4. Out of twenty plants, six (Juncus lomatophyllus, Cyperus sexangularis, Carex austro-africana, Elegia tectorum, Gunnera perpensa, Persicaria senegalensis and Cyperus marginatus) exhibited IC50 values ranging between 32.22 – 71.59 μg/ml for tyrosinase inhibition. Combinational studies of these anti-tyrosinase samples were performed to identify potential interactive properties. Results suggested that four combinations could potentially be synergistic if combined in different ratios due to the 0.6 times increase in efficacy of the combined samples. The identification of chemical compounds in the extract of one of the anti-tyrosinase plants, Persicaria senegalensis, indicated the presence of a steroidal compound, (24S)-Stigmast-5,22(E)-dien-3-β –ol. The chemical constituents present in two bioactive major fractions of intermediate polarity (hexane: dichloromethane) (F14 and F15) against tyrosinase were identified using GC-MS based methods. GC-MS analysis of the fractions revealed the presence of thirty-two and thirty-seven constituents in F14 and F15, respectively, of which twelve were present in both. Previous literature suggests that the constituents responsible for the anti-tyrosinase activity of the intermediate polarity fractions were, (9Z)-9-Octadecenamide or 2,4,5-trimethoxybenzaldehyde for F14 and a Benzenepropanol, à-methyl-á-nitro-, (R*,R*)-(.+.)- (suggested to be 4-(4-Nitrophenyl)-2-butanol) for F15, due to the similarity in their structures and known inhibitors of tyrosinase. The molecular docking was performed using the GOLD program which analyses the interaction between substrate (tyrosinase) flexibility and the conformational flexibility of the ligands (inhibitors) using a genetic algorithm. Results from the docking, expressed as Gold fitness scores, indicated that all previously isolated flavonoid molecules and those identified through GC-MS from P. senegalensis, have the ability to enter and interact with the active site of tyrosinase. Larger molecules are more likely to protrude into the enzyme, therefore exhibited lower inhibitory potential (gentisic acid-5-O-(2′-O-glucopyranosyl)-rhamnoside; myricetin-3-O-rhamnoside; quercetin-3-O-glucopyranoside and quercetin-3-O-rhamnoside) while, smaller molecules (3,7,4′-trimethoxy-kaempferol; 5-hydroxy-7-methoxy-isoflavone; apigenin and quercetin) exhibited a similar binding pose to that of kojic acid. Only the suggested Benzenepropanol, à-methyl-á-nitro-, (R*,R*)-(.+.)- (4-(4-Nitrophenyl)-2-butanol) (identified through GC-MS analysis of both intermediate polarity fractions) showed significant molecular docking results through obtaining a high fitness score in addition to close interactions with both the copper ions. Suggesting that this compound could be the compound responsible for the in vitro inhibition of tyrosinase observed in the initial evaluation of the plant. This study highlights new opportunities for the collection of medicinal plants worldwide, expanding the search for resources not only in terrestrial ecosystems, but freshwater aquatic and wetlands too. Plant Science MSc (Medicinal Plant Sciences) Unrestricted Faculty of Natural and Agricultural Sciences SDG-15: Life on land SDG-14: Life below water 2026-06-29T08:28:38Z 2026-06-29T08:28:38Z 2018-04 2018-01 Dissertation A2018 http://hdl.handle.net/2263/110797 en © 2025 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Wetland plants Aquatic plants Therapeutic and medicinal potential Medicinal Plant Sciences South African aquatic and wetland plants The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title | The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title_full | The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title_fullStr | The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title_full_unstemmed | The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title_short | The therapeutic and medicinal potential of South African freshwater aquatic and wetland plants |
| title_sort | therapeutic and medicinal potential of south african freshwater aquatic and wetland plants |
| topic | UCTD Wetland plants Aquatic plants Therapeutic and medicinal potential Medicinal Plant Sciences South African aquatic and wetland plants |
| url | http://hdl.handle.net/2263/110797 |