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The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes
Thesis (MSc)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613780575256576 |
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| access_status_str | Open Access |
| author | Abrahams, Claudia Cathrine |
| author2 | Lilly, M. |
| author_browse | Abrahams, Claudia Cathrine Lilly, M. |
| author_facet | Lilly, M. Abrahams, Claudia Cathrine |
| author_sort | Abrahams, Claudia Cathrine |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131996 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:41:35.119Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131996 The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes Abrahams, Claudia Cathrine Lilly, M. Patterton, H. G. Stellenbosch University. Faculty of Science. Dept. of Biochemistry. Rooibos tea -- Therapeutic use Aspalathus -- Therapeutic use Keratinocytes -- Differentiation Inflammation -- Immunological aspects Skin -- Inflammation-- Chemotherapy Polyphenols -- Mechanism of action UCTD Thesis (MSc)--Stellenbosch University, 2025. Abrahams, C.C. 2025. The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes. Unpublished masters thesis. Stellenbosch: Stellenbosch Univeristy [online]. Available: https://scholar.sun.ac.za/items/1f9590b8-768b-4573-8cff-b8b8af4b2ead ENGLISH ABSTRACT: The skin serves as the body's first line of defense, providing a barrier against environmental stressors and invading pathogens, and actively participates in the immune response. Keratinocytes play an integral part in immune surveillance by initiating and modulating the immune response in the epidermis. Skin inflammation is a physical response that safeguards the body against various insults, including physical injury, exposure to toxic chemicals, UV irradiation, and microbial agents. Disruption to the skin's barrier integrity can increase the risk of microbial invasion and subsequent infection. Aspalathus linearis (rooibos) is an herbal plant indigenous to South Africa. It is rich in polyphenolic compounds which have been shown to possess potent antioxidant and antiinflammatory properties. Various studies have highlighted the potential of rooibos in mitigating skin inflammation. This study aimed to elucidate the immunomodulatory properties of rooibos, given the interplay between inflammation, oxidative stress, and cytokine regulation. The goal of this study is to improve early detection and treatment of prevalent skin diseases by gaining a deeper understanding of the underlying physiological and pathological mechanisms. Aqueous extracts of both unfermented (RU) and fermented (RF) rooibos were prepared, and chemical characterization and antioxidant properties were evaluated. The RU extract contains higher levels of dihydrochalcones, such as aspalathin and nothofagin, compared to the RF extract the modulation of cell growth indices, including cell viability and proliferation, was critically assessed in human skin keratinocyte (HaCaT) cells. Both extracts decreased cell viability and proliferation in a dosedependent manner. Cell viability, interleukin-8 (IL-8) and caspase production was used to determine the optimal concentration of lipopolysaccharide (LPS) and tumour necrosis factor alpha (TNF- to establish the inflammatory model. Based on these results, 10 ug/mL LPS and 25 ng/mL TNF- were selected. HaCaT cells were pre-treated with various concentrations of RU or RF extracts and exposed to LPS/TNF- for 4 or 24 hours. Cell viability, caspase production, gene (qPCR) and protein expression (ELISA) of pro-inflammatory cytokines and the expression of antioxidant genes were investigated to determine the anti-inflammatory and antioxidant potential of the extracts. Both extracts displayed anti-inflammatory properties by decreasing the gene expression of COX-2, IL-8, and IL-6. Pre-treatment with the extracts resulted in modulation of the NF- B and Nrf2 signalling pathway as well as the regulation of the antioxidant genes GPx and SOD1. To our knowledge, no studies have investigated the effects of rooibos on the skin proteome to date. Proteomic studies can help elucidate the molecular mechanisms underlying the effects of teas and their bioactive compounds. A label-free quantitative proteomic approach was employed to detect changes in protein expression and to examine the effect of rooibos extracts on HaCaT cells in vitro. Comparative proteomic analysis was performed to investigate the molecular mechanisms and pathways affected by unfermented and fermented rooibos extracts. HaCaT cells were exposed to RU and RF, both at concentrations of 0.1 and 0.2 mg/mL, respectively. Liquid chromatographytandem mass spectrometry (LC-MS/MS) was performed to quantify intracellular proteins of RU and RF treated groups and untreated control groups. Differentially abundant proteins (DAPs) were then identified by bioinformatic analyses and visualised using volcano plots. Gene Ontology analysis, using human databases, functionally annotated the DAPs. A total of 59 significant DAPs were identified between RU and RF treated groups compared to the untreated control groups. The identified upregulated DAPs play a significant role in the regulation of keratinocyte differentiation and proliferation. Thus, contributing to the maintenance of the skin barrier, and facilitating cell migration, all critical processes for skin health and wound healing. Collectively, the signalling pathway and proteomic analyses indicate that rooibos exerts protective effects against inflammation in skin keratinocytes. Consequently, these findings support the therapeutic potential of rooibos for inflammatory skin disorders and provide a foundation for further research. AFRIKAANSE OPSOMMING: Die vel dien as die liggaam se eerste verdedingsmeganisme, en bied 'n beskermende laag teen eksterne stres faktore en indringende patogene. Dit speel respons. Keratinosiete speel 'n integrale rol in immuunstelsel deur die immuun respons in die epidermis te inisieer en te moduleer. Vel inflammasie is 'n fisiese reaksie wat die liggaam beskerm teen verskeie aanvalle, insluitend fisiese beserings, blootstelling aan giftige chemikalieë, UV-bestraling en mikrobiese agente. Verstoring van die vel se versperringintegriteit kan die risiko van mikrobiese inval en daaropvolgende infeksie verhoog. Aspalathus linearis (rooibos) is 'n kruieplant inheems aan Suid-Afrika. Dit is ryk aan polifenoliese verbindings wat toon dat dit kragtige antioksidant- en anti- inflammatoriese eienskappe besit. Verskeie studies het die potensiaal van rooibos in die versagting van velontsteking beklemtoon. Hierdie studie het ten doel gehad om die immunomodulerende eienskappe van rooibos te ondersoek, gegewe die wisselwerking tussen inflammasie, oksidatiewe stres en sitokienregulering. Die doel van hierdie studie is om vroeë opsporing en behandeling van algemene velsiektes te verbeter deur 'n dieper begrip van die onderliggende fisiologiese en patologiese meganismes te verkry. Water ekstrakte van beide ongefermenteerde (RU) en gefermenteerde (RF) rooibos is voorberei, en chemiese karakterisering en antioksidant-eienskappe is geëvalueer. Die RU-ekstrak bevat hoër vlakke van dihidrochalcone, soos aspalatien en nothofagien, in vergelyking met die RF-ekstrak. Die modulasie van selgroeiparameters, insluitend sellewensvatbaarheid en -proliferasie, is krities geëvalueer in menslike velkeratinosiet (HaCaT) selle. Beide ekstrakte het sellewensvatbaarheid en -proliferasie op 'n dosisafhanklike wyse verminder. Sellewensvatbaarheid, interleukien-8 (IL-8) en kaspase-produksie is gebruik om die optimale konsentrasie van lipopolisakkaried (LPS) en tumornekrosefaktor alfa (TNF- inflammatoriese model te vestig. Gebaseer op hierdie resultate is 10 µg/mL LPS en 25 ng/mL TNF- gekies. HaCaT-selle is vooraf behandel met verskeie konsentrasies van RU- of RF-ekstrakte en blootgestel aan LPS/TNF- uur. Sellewensvatbaarheid, kaspase-produksie, geen (qPCR) en proteïenuitdrukking (ELISA) van pro-inflammatoriese sitokiene en die uitdrukking van antioksidantgene is ondersoek om die anti-inflammatoriese en antioksidant-potensiaal van die ekstrakte te bepaal. Beide ekstrakte het anti-inflammatoriese eienskappe getoon deur die geenuitdrukking van COX-2, IL-8 en IL-6 te verminder. Voorbehandeling met die ekstrakte het gelei tot modulasie van die NF- Nrf2 seintransduksiebaan, asook die regulering van die antioksidantgene GPx en SOD1. Na ons wete het geen studies totop hede die effekte van rooibos op die velproteoom ondersoek nie. Proteomiese studies kan help om die molekulêre meganismes onderliggend aan die effekte van tee en hul bioaktiewe verbindings te ontrafel. 'n kwantitatiewe proteomiese benadering is gebruik om veranderinge in proteïenuitdrukking op te spoor en die effek van rooibosekstrakte op HaCaT-selle in vitro te ondersoek. Vergelykende proteomiese analise is uitgevoer om die molekulêre meganismes en seintransduksiepaaie wat deur ongefermenteerde en gefermenteerde rooibosekstrakte beïnvloed word, te ondersoek. HaCaT-selle is blootgestel aan RU en RF, beide teen konsentrasies van onderskeidelik 0.1 en 0.2 mg/mL. Vloeistofchromatografie- tandemmassaspektrometrie (LC-MS/MS) is uitgevoer om intrasellulêre proteïene van RU- en RF- behandelde groepe en onbehandelde kontrolegroepe te kwantifiseer. Differensieël oorvloedige proteïene (DAPs) is toe deur bioinformatiese analise geïdentifiseer en met behulp van vulkaangrafieke gevisualiseer. Geenontologie-analise, met behulp van menslike databasisse, het die DAPs funksioneel geannoteer. 'n Totaal van 59 beduidende DAPs is geïdentifiseer tussen RU- en RF- behandelde groepe in vergelyking met die onbehandelde kontrolegroepe. Die geïdentifiseerde opgereguleerde DAPs speel 'n beduidende rol in die regulering van keratinosietdifferensiasie en - proliferasie. Dus dra dit by tot die instandhouding van die vel, en fasiliteer selmigrasie, alle kritieke prosesse vir velgesondheid en wondgenesing. Gesamentlik dui die seintransduksiepaaie- en proteomiese analise aan dat rooibos beskermende effekte teen ontsteking in velkeratinosiete uitoefen. Gevolglik ondersteun hierdie bevindinge die terapeutiese potensiaal van rooibos vir inflammatoriese velsiektes en bied 'n grondslag vir verdere navorsing. Masters 2025-05-12T09:01:02Z 2025-05-12T09:01:02Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/131996 Stellenbosch University 149 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Rooibos tea -- Therapeutic use Aspalathus -- Therapeutic use Keratinocytes -- Differentiation Inflammation -- Immunological aspects Skin -- Inflammation-- Chemotherapy Polyphenols -- Mechanism of action UCTD Abrahams, Claudia Cathrine The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title | The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title_full | The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title_fullStr | The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title_full_unstemmed | The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title_short | The protective effects of Aspalathus linearis (Rooibos) extracts against LPS/TNF-α induced inflammation in keratinocytes |
| title_sort | protective effects of aspalathus linearis rooibos extracts against lps tnf α induced inflammation in keratinocytes |
| topic | Rooibos tea -- Therapeutic use Aspalathus -- Therapeutic use Keratinocytes -- Differentiation Inflammation -- Immunological aspects Skin -- Inflammation-- Chemotherapy Polyphenols -- Mechanism of action UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131996 |
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