Le rooibos est une tisane produite à partir d'une plante sud-africaine endémique (Aspalathus linaris), typique de la formation végétale fynbos. Il s'agit d'une production localisée ou « produit de terroir » au sens où elle est inscrite dans le temps et que les savoir-faire de production et la ressource sont liés à une région, le sud-ouest du pays. Cette production combine tous les caractères constitutifs d'un patrimoine : elle est produite collectivement, ancrée dans le temps et dans l'espace, transmise ou conservée. Le rooibos se situe donc dans le champ des études sur la patrimonialisation des productions localisées. Il fait actuellement l'objet d'un projet de valorisation par une indication géographique (IG) et présente à ce titre un caractère emblématique pour ces recherches dans les pays du Sud. Afin d'éclairer le processus de valorisation, notre recherche a consisté à étudier les dynamiques à l'origine de sa dimension patrimoniale. Nous montrons que cette production est indissociable des contextes et des enjeux (politiques, sociaux, identitaires) qui ont traversé la société sud-africaine à différentes époques. La filière du rooibos s'est révélée être un objet d'étude privilégié pour observer les tensions nationales dans l'Afrique du Sud post-apartheid. Nous observons une volonté de promouvoir une nation multiculturelle qui tranche avec celle de conserver la structure hiérarchique à l'origine des inégalités socio-économiques. L'imaginaire du rooibos associe l'ingénierie des producteurs afrikaners, le savoir-faire des ouvriers métis et l'utilisation de figures patrimoniale comme celle des Khoesan ; mais d'un autre côté, l'organisation actuelle de la filière reproduit les disparités au sein des acteurs locaux de la production, d'une part entre producteurs et ouvriers agricoles et d'autre part entre producteurs afrikaners et métis. Nos résultats suggèrent que la construction des nouveaux patrimoines sud-africains n'est pas nécessairement un facteur d'intégration et de réconciliation nationales.

Thesis (MSc Food Sc) (Food Science)--University of Stellenbosch, 2005. / Near infrared spectroscopy (NIRS) and UV/Vis spectrophotometric methods were investigated as rapid and/or more economical methods to quantify the major monomeric phenolic compounds, soluble solid content (SSC), total polyphenol content (TPC) and total antioxidant activity (TAA) of green rooibos and Cyclopia genistoides.

Thesis (MSc Food Sc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Rooibos tea, produced from the endemic South African fynbos plant Aspalathus linearis, has various healthpromoting benefits which can largely be attributed to its phenolic composition. In this study, the reversedphase liquid chromatographic (RP-LC) separation of the principal phenolic constituents of aqueous rooibos infusions was optimised on conventional high-performance liquid chromatography (HPLC) instrumentation. The phenolic constituents comprised dihydrochalcones (aspalathin and nothofagin), flavones (orientin, isorientin, vitexin, isovitexin, luteolin, luteolin-7-O-glucoside and chrysoeriol), flavonols (quercetin, isoquercitrin, hyperoside and rutin), a hydroxycinnamic acid (ferulic acid) and a phenylpropanoid (phenylpyruvic acid glucoside, PPAG). A systematic approach towards method development was adopted: resolution was optimised by simultaneous optimisation of gradient conditions and temperature on a sub-2 6m phase to exploit the benefits of this phase for fast routine analyses. The developed HPLC method, utilising photodiode-array (PDA) detection, yielded complete separation of the 15 target analytes on the 1.8 µm C18 column, thermostatted to 37°C, within 37 min (total analysis time: 50 min). The method was successfully validated and demonstrated its suitability for the fast, quantitative analysis of aqueous infusions of unfermented and fermented rooibos. Mass spectrometric (MS) and tandem MS detection confirmed peak purity and permitted the tentative identification of 13 additional phenolic compounds, including a flavonol Odiglycoside (quercetin-3-O-robinobioside), a luteolin-6-C-pentoside-8-C-hexoside and a novel C-8-hexosyl derivative of aspalathin reported here for the first time. The HPLC-PDA method was subsequently applied to a large number of fermented rooibos samples representative of different production seasons (2009, 2010 and 2011) and quality grades (grades A, B, C and D) to capture as much potential variation in the phenolic composition as possible. Production season had no clear effect on the levels of the individual phenolic compounds in ‘cup-of-tea’ rooibos infusions, whilst high quality tea (grades A and B) was associated with higher levels of phenolic compounds and soluble solids than low quality tea (grades C and D). Steam-pasteurisation of the plant material, required to obtain a product of high microbiological quality, induced significant reductions in the mean values of most of the phenolic compounds in rooibos infusions. The major phenolic constituents of steam-pasteurised, fermented rooibos were isoorientin and orientin, whilst quercetin-3-O-robinobioside, PPAG and aspalathin were also present in high concentrations. Representative content values of the major phenolic compounds present in a typical ‘cup-of-tea’ rooibos infusion were thus obtained and the generated data are suitable for inclusion in food composition databases. The application of comprehensive two-dimensional liquid chromatography (LCxLC) was investigated as an alternative approach for the detailed investigation of rooibos phenolics. The combination of hydrophilic interaction chromatography (HILIC) in the first dimension and RP-LC in the second dimension offered different separation selectivities and hence a high degree of orthogonality. HILICxRP-LC provided a significant improvement in resolution, as is evident from practical peak capacities in excess of 2000 and 800 for the off-line and on-line methods, respectively. Further optimisation, particularly of the first dimension separation, is however required to improve the LCxLC separation of complex rooibos phenolic fractions. / AFRIKAANSE OPSOMMING: Gebruik van rooibostee, berei vanaf die eg Suid-Afrikaanse fynbosplant Aspalathus linearis, hou verskeie gesondheidsvoordele in wat grootliks toegeskryf kan word aan sy fenoliese samestelling. Die skeiding van die hoof fenoliese verbindings van ’n koppie rooibos is in hierdie studie deur middel van omgekeerde-fase vloeistof chromatografie (RP-LC) op konvensionele hoë-druk vloeistof chromatografiese (HPLC) toerusting geoptimiseer. Die fenoliese verbindings was verteenwoordigend van dihidrogalkone (aspalatien en notofagien), flavone (orientien, isoorientien, viteksien, isoviteksien, luteolien, luteolien-7-O-glukosied en krisoeriol), flavonole (kwersetien, isokwersetrien, hiperosied en rutien), ‘n hidroksiekaneulsuur (ferulasuur) en ‘n fenielpropanoied (fenielpirodruiwesuurglukosied, PPAG). Die ontwikkeling van die metode was sistematies benader: resolusie is op ‘n geselekteerde 1.8 6m stationêre fase met welombekende kinetiese voordele geoptimiseer deur die gradiëntkondisies en kolomtemperatuur gelyktydig te optimiseer. Die ontwikkelde HPLC metode, gekoppel aan ultraviolet-fotodiode deteksie (PDA), het binne 37 min (totale analiese tyd: 50 min) volledige skeiding van die 15 standaard verbindings op die 1.8 µm C18 kolom teen 37°C bewerkstellig. Die metode is suksesvol gevalideer en het sy toepaslikheid vir vinnige, kwantitatiewe analiese van ongefermenteerde en gefermenteerde rooibos gedemonstreer. Piek suiwerheid is deur middel van massa spektrometrie (MS) en tandem MS bevestig, wat ook die identifikasie van 13 addisionele verbindings toegelaat het, insluitende ‘n flavonol O-diglukosied (kwersetien-3-O-robinobiosied), ‘n luteolien-6-Cpentosied- 8-C-heksosied en ‘n unieke C-8-heksosiel afgeleide van aspalatien wat vir die eerste keer hier gemeld is. Die geoptimiseerde HPLC-PDA metode is gevolglik toegepas vir die analiese van ‘n groot aantal gefermenteerde rooibos monsters, verteenwoordigend van verskillende produksie seisoene (2009, 2010 en 2011) en kwaliteitsgrade (A, B, C en D). Hierdie lukraak-geselekteerde monsters het soveel as moontlik potensiële variasie in die fenoliese samestelling verseker. Produksie seisoen het geen definitiewe effek op die vlakke van die individuele fenoliese verbindings in ’n koppie rooibos gehad nie, terwyl hoë kwaliteit rooibos (grade A en B) geassosieër was met hoër vlakke van die individuele fenoliese verbindings en oplosbare vastestowwe in vergelyking met lae kwaliteit rooibos (grade C en D). Stoompasteurisasie van rooibos plantmateriaal, noodsaaklik om ‘n produk van hoë mikrobiologiese gehalte te verseker, het gelei tot ‘n betekenisvolle afname in meeste fenoliese verbindings in ’n koppie rooibos. Die hoof fenoliese verbindings van ‘n koppie stoom-gepasteuriseerde, gefermenteerde rooibos was orientien en isoorientien, terwyl kwersetien-3-O-robinobiosied, PPAG en aspalatien ook in noemenswaardige hoeveelhede aanwesig was. Verteenwoordigende waardes van die hoof fenoliese verbindings aanwesig in ‘n tipiese koppie rooibos is derhalwe verkry en die data is geskik vir insluiting in voedsel-samestelling databasisse. Die analiese van rooibos fenole met omvattende twee-dimensionele vloeistof chromatografie (LCxLC) is bestudeer as ‘n alternatiewe metode om verdere insig tot hierdie komplekse fenoliese fraksie te verkry. Die kombinasie van hidrofiliese interaksie chromatografie (HILIC) in die eerste dimensie en RP-LC in die tweede dimensie het ‘n uiters gesogte lae graad van korrelasie verskaf. HILICxRP-LC het ‘n besonderse toename in resolusie teweeg gebring, gekenmerk deur praktiese piek kapasiteite hoër as 2000 en 800 vir die af-lyn en aan-lyn metodes, onderskeidelik. Verdere optimisering, veral van die eerste dimensie skeiding, is egter nodig om die LCxLC skeiding van rooibos fenole te verbeter.

Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2005. / Antimutagenic activity of aqueous extracts of fermented and unfermented Cyclopia spp., i.e. C. intermedia, C. subternata, C. genistoides and C. sessiliflora against metabolically activated aflatoxin B1 (AFB1) in the Salmonella mutagenicity assay with tester strain TA100, was compared to that of fermented and unfermented Aspalathus linearis (rooibos) and Camellia sinensis (black, oolong and green) teas. Possible mechanisms involved in in vitro antimutagenic activity of these teas were investigated, i.e. the stabilising effect of the unfermented Cyclopia spp., unfermented rooibos and green tea on rat liver cytochrome P450 in the S9 fraction from Aroclor 1254 treated rats and their modulation of aniline-induced Type II difference spectra in the microsomal fraction. Inhibition of lipid peroxidation in rat liver S9, by the teas, was assessed to determine whether protection against lipid peroxidation may play a role in cytochrome P450 stability in vitro. Correlation of the antimutagenic activity of the teas with their stabilising effect on cytochrome P450 and inhibition of lipid peroxidation, provided insight into possibly related mechanisms. Antimutagenic activity correlated weakly with a decreased stabilising effect of the teas on cytochrome P450 (r = 0.411, P = 0.013) and the inhibition of lipid peroxidation (r = 0.475, P = 0.003). Decreased stability of cytochrome P450 was associated with substantial lipid peroxidation occurring in rat liver S9. Effective inhibition of lipid peroxidation and stabilising of cytochrome P450 in S9 was evident in the presence of the teas, but no correlation (r = 0.018, P = 0.915) existed for the effect of unfermented teas on cytochrome P450 stability with inhibition of lipid peroxidation. Black tea exhibited the highest protection against AFB1-induced mutagenesis and fermented C. intermedia offered the least protection. “Fermentation” resulted in increased antimutagenic activity of Camellia sinensis and rooibos teas, while the antimutagenic activity of Cyclopia spp. decreased with fermentation except for C. genistoides. Unfermented teas significantly (P < 0.05) stabilised cytochrome P450, with rooibos more effective (P < 0.05) than green tea, but similar (P < 0.05) to Cyclopia spp. Green tea demonstrated the highest inhibition of lipid peroxidation, while the inhibition exerted by rooibos was similar (P > 0.05) to unfermented Cyclopia spp., except for C. genistoides exhibiting the least inhibition. Total polyphenol, flavanol and flavonol/flavone contents of the respective teas were correlated with activity in terms of antimutagenicity, stabilising of cytochrome P450 and inhibition of lipid peroxidation. Antimutagenic activity of Cyclopia spp. correlated with its total polyphenol (r = 0.805, P < 0.0001) and flavanol (r = 0.653, P < 0.0001) contents, while a weak negative correlation (r = -0.456, P = 0.026) was observed for the inhibition of lipid peroxidation by unfermented Cyclopia spp. with the flavonol/flavone content. Antimutagenicity of Cyclopia spp. correlated weakly (r = 0.363, P = 0.012) with its hesperidin content. Antimutagenic activity of rooibos tea correlated moderately (r = 0.751, P < 0.005) with its flavonol/flavone content and specifically the flavones orientin (r = 0.674, P < 0.023) and iso-orientin (r = 0.728, P < 0.011). A strong negative correlation (r = -0.918, P < 0.0001) of antimutagenicity of rooibos with its aspalathin content was observed. Antimutagenic activity of Camellia sinensis teas did not correlate with their total polyphenol, flavanol or flavonol/flavone contents. The flavanol content of green tea showed a good, but marginal (P < 0.1) correlation (r = 0.824, P = 0.086) with decreased cytochrome P450 stability. The modulation of aniline-induced Type II binding to microsomal cytochrome P450 by green tea differed significantly (P < 0.05) from the modulation exhibited by rooibos and Cyclopia spp. Flavonoid glycosylation appeared to influence antimutagenic activity, stabilising of cytochrome P450 and modulation of substrate binding of selected phenolic compounds. The present study indicates that rooibos and Cyclopia spp. have in vitro antimutagenic activity against AFB1, suggesting that consumption of these two herbal teas may have beneficial health effects. It is also suggested that stabilising of cytochrome P450 by tea, and interaction of tea constituents with cytochrome P450, may influence their in vitro antimutagenic activity.

Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The sensory characteristics and chemical composition of rooibos infusions were analysed to establish the extent of variation in sensory attributes and compositional parameters, and investigate whether correlations exist between the sensory characteristics and the phenolic composition. To capture as much potential variation as possible, 69 rooibos samples were collected throughout the 2009 harvesting season from different production areas. The samples were also representative of the different quality grades (A, B, C or D) which are based on the appearance of the leaves, and the colour and flavour of the infusion. Quantitative descriptive analysis was used to develop sensory profiles for each of the rooibos infusions. Considerable variation in the sensory characteristics was observed, highlighting the need for standardised terminology that can be used to describe what is often referred to as “characteristic” rooibos flavour. Aroma, flavour, taste, and mouthfeel descriptors were generated and assembled into a rooibos sensory wheel. The most recurring attributes were selected to compile a rooibos sensory lexicon which provides a definition and a reference standard for clarification of each term. A combination of “honey”, “woody” and “fynbos-floral” notes with a slightly sweet taste and subtle astringency may be regarded as “characteristic” rooibos attributes indicative of good quality tea. Pleasant “caramel” and “fruity-sweet” notes were also observed in a number of infusions, whereas negative descriptors, associated with poor quality rooibos, included “green” and “hay” flavours. Large variation in the composition of rooibos infusions was revealed through the quantification of soluble solids (SS), total polyphenols (TP), tannins and 14 monomeric phenolic compounds, as well as spectrophotometric colour measurements. High quality rooibos was associated with higher levels of SS, TP, tannins and phenolic compounds than low quality rooibos. Correlations between the compositional parameters and sensory attributes of the infusions indicated that several non-volatile compounds, including enolphenylpyruvic acid-2-glucoside, quercetin-3-glucoside, and iso-orientin, were associated with the characteristic sweet taste of rooibos, while bitterness was related to certain flavonoids such as luteolin, quercetin and aspalathin. The only compound significantly correlated to astringency was rutin, although it is likely that aspalathin and several other monomeric flavonoids also contribute to astringency. The tannin content was not associated with astringency possibly because of the limitations associated with the tannin quantification method. To determine whether compositional changes resulting from steam pasteurisation of rooibos leaves influence the sensory quality of rooibos infusions, differences in the phenolic composition and sensory attributes of infusions, prepared from unpasteurised and pasteurised rooibos, were analysed. Steam pasteurisation significantly reduced the SS, TP and aspalathin content of rooibos infusions, as well as the absorbance, especially at a wavelength of 450 nm. It also resulted in significant reductions in the intensities of most of the aroma and flavour attributes, especially the “green” notes associated with low quality rooibos. After steam pasteurisation the prominent “green” flavour of certain samples was frequently replaced by a “hay” flavour. The taste attributes, sweetness and bitterness, remained unchanged, whereas the astringency of rooibos infusions decreased significantly. / AFRIKAANSE OPSOMMING: Die sensoriese eienskappe en chemiese samestelling van rooibostee is geanaliseer ten einde die mate van variasie van die sensoriese sowel as die chemiese profiel te bepaal, asook om vas te stel of korrelasies bestaan tussen die sensoriese eienskappe en die fenoliese samestelling van rooibostee. Om soveel as moontlik potensiële variasie in te sluit, is 69 rooibos monsters tydens die 2009 oesseisoen van verskillende produksiegebiede versamel. Die monsters is ook verteenwoordigend van die verskillende kwaliteitgrade (A, B, C en D), wat op grond van die voorkoms van die teeblare, en die kleur en geur van die tee toegeken is. Kwantitatiewe beskrywende analise is gebruik om ‘n sensoriese profiel vir elke rooibostee op te stel. Aansienlike variasie in die sensoriese eienskappe is waargeneem. Dit het die behoefte aan gestandaardiseerde terminologie onderskryf, wat gebruik kan word om die term “karakteristieke” rooibos geur in meer detail te omskryf. Spesifieke terme vir aroma, geur, smaak en mondgevoel is geformuleer, en gebruik om ‘n sensoriese wiel vir rooibostee saam te stel. Terme wat die meeste voorgekom het, is gekies om in ‘n sensoriese leksikon vervat te word wat ‘n definisie en ‘n verwysingstandaard vir elke term voorstel. Die “karakteristieke” sensoriese eienskappe van goeie kwaliteit rooibostee kan soos volg gedefinieer word: ’n kombinasie van “heuning”, “houtagtige” en “fynbos-blom” geure met ‘n effense soet smaak en ‘n sagte vrankheid. Aangename “karamel” en “vrugtige-soet” geure is ook waargeneem, terwyl terme soos “groen” en “hooi” met swak kwaliteit rooibostee geassosieer is. Groot variasie in die samestelling van rooibostee is verkry deur kwantifisering van die inhoud van oplosbare vastestowwe (SS), totale polifenole (TP), tanniene, en 14 monomeriese fenoliese verbindings, asook spektrofotometriese kleurmetings. Hoë kwaliteit rooibostee is geassosieer met hoër vlakke van SS, TP, tanniene en fenoliese verbindings in vergelyking met lae kwaliteit rooibos. Korrelasies tussen laasgenoemde parameters en die sensoriese eienskappe het aangedui dat sekere nie-vlugtige verbindings, bv. fenielpirodruiwesuurglukosied, kwersetien-3-glukosied en iso-orientien, geassosieer is met die kenmerkende soet smaak van rooibos, terwyl ‘n bitter smaak geassosieer is met spesifieke flavonoïede soos luteolien, kwersetien and aspalatien. Die enigste verbinding wat betekenisvol gekorreleer het met vrankheid was rutien, maar dit is waarskynlik dat aspalatien en ander monomeriese flavonoïede ook bygedra het tot vrankheid. Die tannieninhoud het nie verband gehou met vrankheid nie, vermoedelik as gevolg van die beperkinge van die chemiese metode vir tannienbepaling. Om te bepaal of stoompasteurisasie van rooibos die sensoriese kwaliteit en chemiese samestelling van rooibostee beïnvloed, is die verskille in fenoliese samestelling en sensoriese eienskappe van die tee, berei van ongepasteuriseerde en gepasteuriseerde rooibos, ondersoek. Stoompasteurisasie het ‘n betekenisvolle verlaging teweegebring van die SS, TP en aspalatien inhoud, sowel as van die absorbansie van die tee, veral by ‘n golflengte van 450 nm. Dit het ook gelei tot ‘n statisties betekenisvolle vermindering van die intensiteit van die meeste aroma en geur eienskappe, veral die sogenaamde “groen” eienskap wat met swak kwaliteit rooibos verbind word. As gevolg van stoompasteurisasie is die opmerklike “groen” geur van sekere ongepasteuriseerde monsters herhaaldelik vervang deur ‘n “hooi” geur. Die smaakeienskappe, soet en bitter, was onveranderd, terwyl vrankheid statisties betekenisvol afgeneem het as gevolg van pasteurisasie.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Stroke is the third leading cause of death in South Africa, killing about 240 people a day and leaving survivors with residual disabilities. There is no clinically approved neuroprotective agent for stroke at the moment but the consumption of plant polyphenols has been suggested to offer neuroprotection against stroke and other neurodegenerative diseases. In this study, we investigated the effects of long term consumption of fermented rooibos herbal tea (FRHT) on ischemia reperfusion brain injury (I-RBI) in rats. Male adult Wistar rats were fed FRHT ad libitum for 7 weeks prior to the induction of ischemic injury by the transient bilateral occlusion of the common carotid arteries (BCCAO) for 20 minutes followed by 24 hours, 4 and 7 days of reperfusion respectively. Rats were then evaluated for neurologic deficits before sacrifice and brains harvested for assessment of brain oedema, blood-brain-barrier (BBB) integrity through Evans blue extravasation (EBE), immunohistochemical studies of apoptosis and lipid peroxidation. Oxygen radical antioxidant capacity and ferric reducing antioxidant power assays were also conducted to assess total antioxidant capacity after ischemia-reperfusion injury. Notably, the long term consumption of fermented rooibos herbal tea prevented brain oedema by reducing cerebral swelling induced by I-RBI. We also observed that fermented rooibos herbal tea offered neuroprotection against damage to the BBB and delayed neuronal death associated with BCCAO as fewer apoptotic cells were identified 7 days post BCCAO reperfusion. Significantly reduced levels of lipid peroxidation and increased levels of total antioxidant capacity were also observed in brain specimens of rats treated with FRHT. Rats treated with FRHT also showed improved neurologic outcomes when compared with the untreated animals. Our results show that FRHT has potent antioxidant and anti-inflammatory properties which can provide neuroprotective effects against neuronal cell loss, cerebral swelling, BBB disruption, lipid peroxidation and neurologic deficits following I-RBI. The use of FRHT is therefore highly recommended for patients with conditions that predispose them to stroke.

Thesis (PhD(FoodSc))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Potential beneficial and/or adverse modulatory effects of polyphenol-enriched extracts of rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) on the antioxidant homeostasis in the liver were investigated. Phase II metabolism of aspalathin and mangiferin, the major polyphenols of rooibos and honeybush respectively, was assessed for potential glucuronidation and sulphation. Glucuronidation resulted in a loss of antioxidant activity for aspalathin and mangiferin in post-column HPLC-DAD-DPPH• and HPLC-DAD-ABTS•+ assays and also a decreased activity of iron chelating properties of mangiferin in the FRAP assay. Two independent studies for 28 and 90 days with polyphenol-enriched extracts (PEEs) of unfermented rooibos [Aspalathus linearis (PER)] and honeybush [Cyclopia. subternata (PECsub) and C. genistoides (PECgen)] in male Fischer rats were conducted to assess possible beneficial and/or adverse biological effects. PECgen was only included in the 28 day study. PEEs were characterised by in vitro antioxidant assays and HPLC analysis. The importance of detailed chemical characterization of rooibos and honeybush when investigating biological effects in vivo is clear as distinctive biological effects and major differences in compositions were evident. Biological parameters included were serum chemical parameters, activities of selected antioxidant enzymes, levels of glutathione and the modulation of expression of oxidative stress and antioxidant defense related genes in the liver. Sub-chronic (90 days) exposure of rats to PER and PECsub both adversely affected iron absorption significantly (P<0.05) and significantly (P<0.05) and markedly lowered levels of reduced glutathione (GSH) in the liver. The high levels of polyphenol intake were implicated and interaction with glutathione was postulated to occur via catechol o-quinone conjugations with GSH. This was also implicated in the significantly (P<0.05) increased activity of glutathione reductase (GR) following 28 days. These findings suggest that PEEs from rooibos and honeybush have the potential to alter the glutathione homeostasis, which could contribute to oxidative status in the liver. PECsub resulted in alterations in the liver biliary system which was manifested as significantly (P<0.05) increased serum total bilirubin (Tbili) and alkaline phosphatase (ALP), depending on the age of the rats, level of total polyphenols and duration of exposure. The expression of a number of oxidative stress and antioxidant defense related genes were differentially altered by the PEEs of rooibos and honeybush in rat liver and further indicated potential oxidative stress. Modulatory effects of PEEs on expression of 84 of these genes in rat liver were assessed with a quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) array and provided additional insights into the possible adverse and protective effects of rooibos and honeybush. Further investigation on total polyphenol dose levels and time of exposure in the application of PEEs of rooibos and honeybush as dietary supplements and functional foods is recommended and will also be of value in anticipated regulatory requirements for future substantiation of safety and efficacy. / AFRIKAANSE OPSOMMING: Die moontlike voordelige en/of nadelige modulerende effekte van polifenol-verrykde ekstrakte van rooibos (Aspalathus linearis) en heuningbos (Cyclopia spp.) op die antioksidant homeostasis in die lewer is ondersoek. Die fase II metaboliete van aspalatien en mangiferin, die hoof verbindings in rooibos en heuningbos onderskeidelik, is ondersoek t.o.v. glukuronidering en sulfonering. Glukuronidasie het gelei tot n verlies in antioksidant aktiwiteit van aspalatien en mangiferin soos bepaal in post-kolom HPLC-DAD-DPPH• en HPLC-DADABTS•+ toetse, asook verminderde interaksie met yster van mangiferin in die FRAP toets. Twee onafhanklike studies van 28 en 90 dae is onderneem met polifenol-verrykde ekstrakte (PVEs) van ongefermenteerde rooibos [Aspalathus linearis (PVR)] en heuningbos [Cyclopia. subternata (PVCsub) and C. genistoides (PVCgen)] in manlike Fisher rotte om die moontlike voordelige en/of nadelige biologiese effekte te ondersoek. PECgen was slegs in die 28 dae studie ingesluit. PVEs is gekarrakteriseer deur in vitro antioksidant en HPLC analises. Die belang van chemiese karaktirisering van rooibos en heuningbos tydens ondersoeke na biologiese aktiwiteit is duidelik aangesien verskeie en variërende biologiese aktiwiteite en verskille in die komposisie in die huidige studie gesien is. Die biologiese parameters wat ondersoek is om die effek van die PVEs te bepaal het serum kliniese parameters, aktiwiteit van geselekteerde ensieme, glutatioon en evaluering van die ekspressie van oksidatiewe en antioksidant verwante gene in die lewer, ingesluit. Sub-kroniese (90 dae) blootstelling van rotte aan PVR en PVCgen het yster absorpsie negatief beïnvloed. Die beduidende (P<0.05) verlaagde vlak van gereduseerde glutatioon in die lewer was toegeskryf aan die hoë vlakke van polifenole ingeneem tydens die studie en word moontlik veroorsaak deur n spesifieke katekol o-konjugasie van GSH. Hierdie interaksie was ook moontlik die oorsaak van n beduidende (P<0.05) toename in die aktiwiteit van glutatioon reduktase. Dié bevindinge het moontlike implikasies t.o.v die glutatioon homeostase en is n moontlike indikase dat PVEs van rooibos kan bydra tot oksidatiewe stres. PVCsub het veranderinge in die lewer gal-sisteem tot gevolg gehad aangesien daar n beduidende (P<0.05) verhoging in die serum totale bilirubin en alkalien fosfaat was. Hierdie veranderinge is beïnvloed deur die ouderdom, vlakke van die totale polifenole en die periode van blootstelling. Die uitdrukking van oksidatiewe en antioksidant verwante gene is op verskillende maniere beïnvloed deur die PVEs van rooibos en heuningbos in rot lewer and dien as n verdere indikasie van onderliggende oksidatiewe stres. Die modulerende effekte van PVEs op geenuitdrukking het gelei tot additionele insig aangaande die moontlike skadelike of beskermende eienskappe van PVEs vir gebruik as kruie produkte of dieet aanvullings. Die indikasies van moontlike oksidatiewe stres was duidelik van biologiese parameters en modulering van geenuitdrukking in die lewer, en vereis verdere ondersoek na die polifenool dosis en periode van toediening voordat PVEs van rooibos en heuningbos as funksionele voedsel produkte gebruik word. Hierdie ondersoek sowel as toekomstige ondersoeke in hierdie verband sal van waarde wees vir regulatoriese vereistes omtrent die veiligheid en effektiwiteit van rooibos en heuningbos kruie produkte.

Dissertation (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This thesis provides the first scientific evidence on the cancer modulating properties of two unique South African herbal teas, rooibos (Aspalathus Iinearis) and honeybush (Cyclopia intermedia) utilizing in vitro as well as in vivo carcinogenesis assays by: • Demonstrating the in vitro antimutagenic activity of aqueous extracts of the herbal teas against the metabolic activated mutagens, 2-acetylaminofluorene (2- AAF) and the mycotoxin, aflatoxin B1 (AFB,) as well as, to a certain extent, against the direct acting mutagen, hydrogen peroxide, utilizing the Salmonella typhimurium mutagenicity assay. • Increasing the activity of hepatic drug metabolizing enzymes, glutathione Stransferase alpha and UPD-glucuronosyl transferase, and reduced the oxidative stress by stabilizing the level of reduced glutathione (GSH) resulting in an increased hepatic reduced to oxidized glutathione ratio (GSG:GSSG). No toxic effects were noticed in rats consuming the herbal teas for 10 weeks as their sole source of drinking fluid. • Demonstrating the ex vivo modulation of 2-AAF- and AFB1-induced mutagenesis by sub- cellular hepatic fractions of rats consuming the herbal teas in the Salmonella mutagenicity assay. Hepatic cytosolic fractions protected against mutagenesis of both mutagens, while the microsomal fractions exhibited a reduced capacity to metabolize AFB1 to its active mutagenic metabolite. • Providing evidence for the in vivo modulation of tumour promotion using the liver as well as the two-stage skin carcinogenesis animal models. The unprocessed herbal teas arrested proliferation of the placental form of glutathione-Stransferase (GSTP+) altered cells as well as reduced the total number of enzyme altered foci in the liver of rats. Topical application of polyphenolic fractions of the various herbal teas prior to 12-0-tetra-decanoylphorbol-13-acetate (TPA) tumour promotion, reduced tumour formation in mouse skin initiated with 7,12-dimethylbenz[ ajanthracene (DMBA). The protective effect was illustrated by a decreased tumour incidence, a reduction in tumour volume as well as a delayed onset of tumour development. The f1avanol/proanthocyanidin content of the fractions could playa major role in the protection against skin tumour promotion. • Proposing possible mechanisms whereby rooibos and honeybush herbal teas could exert their cancer modulating properties with respect to in vitro and ex vivo antimutagenicity, in vivo oxidative status and reduced tumour promotion. • Providing evidence that the herbal teas mimic the cancer modulating properties of green and black teas although differences exist, presumably due to differences in the polyphenolic constituents. • Suggesting that rooibos and honeybush herbal teas may play an important role as chemopreventive agents in the modulation of cancer. / AFRIKAANSE OPSOMMING: Hierdie tesis bevat die eerste ondersoek na die effek van waterige en polifenoliese ekstrakte van rooibos (Aspalathus Iinearis) en heuningbos (Cyclopia intermedia) op verskeie aspekte van kankerontwikkeling. Die twee kruietees is uniek aan Suid-Afrika en kan 'n belangrike rol speel in die voorkoming van kanker. Verskillende in vitro so wei as in vivo studies het die volgende getoon: • Antimutageniese aktiwiteite teen die metabolies-geaktiveerde mutagene, 2- asetielaminofluoreen (2-AAF) en die mikotoksien, aflatoksien B1 (AFB1) in die Salmonella fyphimurium mutagenisiteitstoets. 'n Beperkte mate van beskerming is ook verleen teen die oksidatiewe mutageen, waterstofperoksied, sonder metaboliese aktivering. • Verhoogde aktiwiteite van die fase II ensieme, glutatioon S-tranferase alfa en UDP-glukuronidase, wat liggaamsvreemde verbindings metaboliseer. Die kruietees verlaag die oksidasietoestand soos weerspieel word deur 'n toename van gereduseerde glutatioon tot die geoksideerde vorm in die lewer van rotte wat 10 weke hierdie kruietees gedrink he!. Die kruietees het geen toksiese uitwerking op die rotte gehad nie. • Antimutageniese aktiwiteite van subselluiE~re fraksies van die lewer teenoor 2- AAF en AFB1 in die Salmonella toets. Die sitosolfraksie van die rotlewer bied beskerming teen die ge"induseerde mutagenese van beide mutagene, terwyl die mikrosomale fraksie ook die metaboliese aktivering van AFB1 na die aktiewe mutageniese metaboliet verminder. • In vivo modulering van kankerpromosie met behulp van bekende rotlewer en muisvel kankerontwikkelingsmodelle. In die lewermodel het die ongeprosesseerde kruietees beide die ontwikkeling en getal van GSTP+ fokusse onderskeidelik vertraag en verminder. In die geval van die velkankermodel het aanwending van polifenoliese fraksies van die kruietees beskerming gebied teen die ontwikkeling van velkankers by muise. Die aantal en grootte van die tumors het afgeneem terwyl die verskyning daarvan ook vertraag is. • Verskeie meganismes waardeur rooibos- en heuningboslee moonllik kanker kan moduleer word voorgeslel. Verskille in die polifenoliese sameslelling asook hul onderskeie konsenlrasies kan 'n belangrike rol speel in die kankerveranderende effekle van die lees. • Oal gereelde inname van rooibos- en/of heuningboslee moonllik 'n belangrike rol kan speel in die voorkoming van dieel- en omgewings-geYnduseerde kankers.

Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2004.

Background: Clinical studies have shown that tea consumption leads to decreased iron absorption. This finding is however, not supported by epidemiological studies, where no relationship between an increased tea consumption and a lower iron status in a population at risk of iron depletion has been found. Objectives: The main aim of this study was to compare the effects of black tea and Rooibos consumption on the iron status of primary school children in a rural setting in Potchefstroom, South Africa. Methods: One hundred and seventy five children, aged six to fifteen years, participated in this single blind, randomised, parallel intervention trial. Subjects were randomly allocated to receive two 200ml servings of either black tea or Rooibos with milk and sugar. These beverages were consumed during breaks and at the same time as the food h m the school-feeding scheme. The trial proceeded for sixteen weeks. The children received antihelminthic treatment (500mg mebendazole) at baseline. Haemoglobii haematocrit, serum iron, ferritin and transferfin were measured and total iron binding capacity and transferrin saturation were calculated. Trained fieldworkers measured dietary intakes by means of 24-hour dietary recalls and anthropometrists took anthropometric measurements. All the above mentioned data were gathered at the beginning and at the end of the intervention period. Results: Measurements indicated a study population that is malnourished in terms of anthropometrical indices and nutrient intakes. Biochemical markers of iron status also indicated that the population could be at risk of iron depletion. Changes in red blood cell count, haemoglobin, haematocrit, mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), serum iron, transferrin, transferrin saturation, ferritin and total iron binding capacity (TIBC) did not differ significantly between the two groups. Mean red blood cell count, haematocrit, MCV, transferrin and TIBC increased significantly h m baseline to end in both groups (all p<0.0001) and MCH decreased significantly (p<.0001). Mean haemoglobin increased significantly with black tea consumption (p=0.002), although not with the consumption of Rooibos (p=0.073). Conclusion: Black tea or Rooibos consumption has similar effects on the iron status of primary school children. Iron status was not compromised by black tea in comparison with Rooibos. This questions the proposed limitation of black tea consumption as a public health strategy in order to combat iron deficiency in a population with marginal iron status. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2004.