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Elizabeth Joubert - One of the best experts on this subject based on the ideXlab platform.
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Effect of fermented and green Aspalathus linearis extract loaded hydrogel on surgical wound healing in Sprague Dawley rats
2020Co-Authors: Rukayat D Elegbede, Elizabeth Joubert, Dalene De Beer, T Koekemoer, Margaret O. Ilomuanya, Abimbola Sowemimo, Amarachi Nneji, Maryna Van De VenterAbstract:Abstract Background Aspalathus linearis (Rooibos) has been reported to have a high content of phenolic compounds which elicit antioxidant and anti-inflammatory activity in biological systems. In the present study, we evaluated the effects of “fermented” (oxidised) and green Rooibos extracts embedded in gentamicin loaded acrylate copolymer based hydrogels on inflammatory response in surgical wounds in vivo. Method The major phenolic compounds and a phenolic precursor present in the Rooibos extracts were quantified by HPLC. Acute toxicity of the extracts in Swiss albino mice was evaluated up to 1 g/kg body weight. A modification of free radical initial polymerisation of the alkyl acrylate polymer was utilised to formulate hydrogels loaded with different concentrations of the extracts. The hydrogels were evaluated for swelling, skin irritancy, gel index and pH. Surgical wounds were inflicted on 40 healthy male Sprague Dawley rats, randomly designated to groups treated with the extract loaded hydrogels, hydrogel (without extract; control) and 1% framycetin sulphate containing gauze (positive control). In vivo wound healing test post-surgical intervention was carried out following histomorphometric studies. Results All extract loaded hydrogels shortened the time taken for complete wound closure compared to the control. Hydrogels loaded with fermented Rooibos extract performed better than those loaded with green Rooibos extract or the positive control by significantly (p Conclusion Therapeutic properties of green and fermented Rooibos extract loaded hydrogels have been established in vivo, with the best wound healing indices shown by the hydrogels containing fermented Rooibos extract. This is possibly a result of a shorter inflammatory phase resulting in quicker wound closure and reduced fibrosis.
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Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea
2019Co-Authors: Elisabetta Damiani, Elizabeth Joubert, Dalene De Beer, Patricia Carloni, Gabriele Rocchetti, Biancamaria Senizza, Luca Tiano, Luigi LuciniAbstract:Consumption of Rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the (poly) phenolic profile and in vitro antioxidant capacity of infusions prepared from red (‘fermented’, oxidized) and green (‘unfermented’, unoxidized) Rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both Rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green Rooibos and boiled-brewed red Rooibos. However, boiling green and red Rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of Rooibos tea.
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revisiting the caffeine free status of Rooibos and honeybush herbal teas using specific mrm and high resolution lc ms methods
2019Co-Authors: Maria A. Stander, Elizabeth Joubert, Dalene De BeerAbstract:Abstract Two endemic South African herbal teas, namely Rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.), are especially valued for their caffeine-free status. No recent evidence based on state-of-the-art analytical methodology with low limits of detection (e.g. below 1 μg/L) is available. The current study provides such evidence. Randomly selected samples of fermented Rooibos (n = 10) and honeybush herbal teas from four species (n = 10 each), namely C. intermedia, C. subternata, C. genistoides and C. longifolia, were analysed and no caffeine detected. Similarly, no caffeine was detected in green Rooibos and C. genistoides herbal teas (n = 10 each) indicating that it is absent in the plant. Method specificity was shown to be important since peaks with molecular ion [M+H]+ and product ions resembling those of caffeine were detected, although the retention time and accurate mass did not match those of an authentic reference standard for caffeine.
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Aspalathin from Rooibos (Aspalathus linearis): A Bioactive C-glucosyl Dihydrochalcone with Potential to Target the Metabolic Syndrome.
2018Co-Authors: Rabia Johnson, Daneel Ferreira, Dalene De Beer, Christo J. F. Muller, Phiwayinkosi V. Dludla, Elizabeth JoubertAbstract:Aspalathin is a C-glucosyl dihydrochalcone that is abundantly present in Aspalathus linearis. This endemic South African plant, belonging to the Cape Floristic region, is normally used for production of Rooibos, a herbal tea. Aspalathin was valued initially only as precursor in the formation of the characteristic red-brown colour of “fermented” Rooibos, but the hype about the potential role of natural antioxidants to alleviate oxidative stress, shifted interest in aspalathin to its antioxidant properties and subsequently, its potential role to improve metabolic syndrome, a disease condition interrelated with oxidative stress. The potential use of aspalathin or aspalathin-rich Rooibos extracts as a condition-specific nutraceutical is hampered by the limited supply of green Rooibos (i.e., “unfermented” plant material) and low levels in “fermented” Rooibos, providing incentive for its synthesis. In vitro and in vivo studies relating to the metabolic activity of aspalathin are discussed and cellular mechanisms by which aspalathin improves glucose and lipid metabolism are proposed. Other aspects covered in this review, which are relevant in view of the potential use of aspalathin as an adjunctive therapy, include its poor stability and bioavailability, as well as potential adverse herb-drug interactions, in particular interference with the metabolism of certain commonly prescribed chronic medications for hyperglycaemia and dyslipidaemia.
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potential of Rooibos its major c glucosyl flavonoids and z 2 β d glucopyranosyloxy 3 phenylpropenoic acid in prevention of metabolic syndrome
2018Co-Authors: Christo J. F. Muller, Christiaan J. Malherbe, Yutaka Miura, Kazumi Yagasaki, Nireshni Chellan, Elizabeth JoubertAbstract:Risk factors of type 2 diabetes mellitus (T2D) and cardiovascular disease (CVD) cluster together and are termed the metabolic syndrome. Key factors driving the metabolic syndrome are inflammation, oxidative stress, insulin resistance (IR), and obesity. IR is defined as the impairment of insulin to achieve its physiological effects, resulting in glucose and lipid metabolic dysfunction in tissues such as muscle, fat, kidney, liver, and pancreatic β-cells. The potential of Rooibos extract and its major C-glucosyl flavonoids, in particular aspalathin, a C-glucoside dihydrochalcone, as well as the phenolic precursor, Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid, to prevent the metabolic syndrome, will be highlighted. The mechanisms whereby these phenolic compounds elicit positive effects on inflammation, cellular oxidative stress and transcription factors that regulate the expression of genes involved in glucose and lipid metabolism will be discussed in terms of their potential in ameliorating features of the metabolic syndrome and the development of serious metabolic disease. An overview of the phenolic composition of Rooibos and the changes during processing will provide relevant background on this herbal tea, while a discussion of the bioavailability of the major Rooibos C-glucosyl flavonoids will give insight into a key aspect of the bioefficacy of Rooibos.
Jeanine L. Marnewick - One of the best experts on this subject based on the ideXlab platform.
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The efficacy of Rooibos Aspalathus linearis as an ergogenic aid during exercise
2019Co-Authors: Simeon E.h. Davies, Jeanine L. Marnewick, Fanie Rautenbach, Sacha West, Mogammad Sharhidd Taliep, Raeeq GamieldienAbstract:This study investigated whether Rooibos herbal tea Aspalathus linearis has an ergogenic effect during a fatiguing arm strength test to exhaustion. Thirty-two male participants were randomised in a single blinded, cross-over placebo controlled study in which they ingested standardised Rooibos or placebo capsules for four weeks prior to a fatiguing elbow flexion/extension exercise test entailing five sets/bouts of 15 repetitions of maximum voluntary contractions separated by 10-second rest intervals on a Biodex System 3 at a speed of 60° per second. Peak torque flexion (Nm) was consistently higher in the Rooibos experimental (Re) compared to the placebo control (Pc) across the five exercise bouts, and this performance trend during flexion was also seen in the total work (joules) completed, although not significant (P > 0.05). It appears that the antioxidant properties of Rooibos, may have contributed to an improvement in physical performance during a maximal isokinetic arm exercise protocol to induce fatigue.
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Visualization of Aspalathin in Rooibos (Aspalathus linearis) Plant and Herbal Tea Extracts Using Thin-Layer Chromatography
2019Co-Authors: Emily Amor Stander, Jeanine L. Marnewick, Wesley Williams, Yamkela Mgwatyu, Fanie Rautenbach, Marilize Le Roes-hill, Uljana HesseAbstract:Aspalathin, the main polyphenol of Rooibos (Aspalathus linearis), is associated with diverse health promoting properties of the tea. During fermentation, aspalathin is oxidized and concentrations are significantly reduced. Standardized methods for quality control of Rooibos products do not investigate aspalathin, since current techniques of aspalathin detection require expensive equipment and expertise. Here, we describe a simple and fast thin-layer chromatography (TLC) method that can reproducibly visualize aspalathin in Rooibos herbal tea and plant extracts at a limit of detection (LOD) equal to 178.7 ng and a limit of quantification (LOQ) equal to 541.6 ng. Aspalathin is a rare compound, so far only found in A. linearis and its (rare) sister species A. pendula. Therefore, aspalathin could serve as a marker compound for authentication and quality control of Rooibos products, and the described TLC method represents a cost-effective approach for high-throughput screening of plant and herbal tea extracts.
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Rooibos herbal tea: An optimal cup and its consumers
2019Co-Authors: Hannelise Piek, Fanie Rautenbach, Irma Venter, Jeanine L. MarnewickAbstract:Background: Rooibos types and forms and how prepared and flavoured influence the total polyphenol content and total antioxidant capacity (TAC). Aim: To denote an optimal Rooibos cup as having the highest total polyphenol content and TAC, considering the different types, forms, preparation methods and flavourings and amounts (Phase 1), and determine the demographic, lifestyle and Rooibos consumption characteristics of adult Rooibos consumers, and the association of these characteristics with drinking the optimal cup (Phase 2). Setting: Assays: Oxidative Stress Research Centre, Cape Peninsula University of Technology; Consumer survey: George area, South Africa. Method: Phase 1 entailed determining the total polyphenol content (Folin–Ciocalteau method) and TAC (Trolox equivalent antioxidant capacity and ferric-reducing antioxidant power assay) of the prepared Rooibos samples. For Phase 2, a developed, pilot tested questionnaire was used to profile adult Rooibos consumers. Results: Phase 1: the following samples delivered higher total polyphenol content and TAC: green (type), green leaves and powdered extract (forms), and sample steeped for 10 min or longer (preparation method). The identified optimal cup was sample steeped for 10 min or longer. Phase 2: a total of 308 respondents completed the questionnaire. Few consumed more than one Rooibos cup per day (25.3%; n = 78) and the optimal cup (15.9%; n = 49). These latter respondents comprised those who steeped Rooibos in a teapot (not a cup or mug) (p < 0.05). Conclusions: The optimal cup was identified as sample steeped for 10 min or longer. The Rooibos consumers did not consume it sufficiently, nor steeped it long enough
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the combination of red palm oil and Rooibos show anti inflammatory effects in rats
2014Co-Authors: Emma Katenguathamahane, Jeanine L. Marnewick, Olawale Razaq Ajuwon, Novel N Chegou, Gergő Szűcs, Peter Ferdinandy, Tamas Csont, Csaba Csonka, Jacques Van RooyenAbstract:Red palm oil (RPO) and Rooibos have been shown to exhibit cardioprotective properties. RPO is rich in essential fatty acids and fat soluble antioxidants while Rooibos contains polyphenolic compounds with a unique composition of flavonoids. They exert their biological effects in different cellular compartments. Therefore the combination of these two natural food compounds has the potential to enhance the spectrum of available dietary antioxidants in different cellular compartments, which could result in an enhanced protection against certain pathological conditions such as inflammation. Male Wistar rats weighing 150-200 g were supplemented with RPO, Rooibos or their combination for 28 days. The Langendorff system and the lipoposaccharide (LPS)-induced inflammatory model were used to establish if RPO and Rooibos, when supplemented alone or in combination, will reverse the negative effects of LPS on cardiac function at baseline. The effect of dietary intervention was also investigated on modulation of pro-inflammatory and anti-inflammatory cytokines in plasma and myocardial tissue. The LPS resulted in induction of systemic inflammation as evidenced by increased levels of IL-1β in plasma of LPS-treated rats compared to their non-treated control counterparts. Dietary supplementation and LPS treatment did not have an effect on baseline cardiac functional parameters. However, the elevation of IL-1β levels in plasma of LPS-induced rats consuming either RPO or Rooibos alone were paralleled with increased levels of the anti-inflammatory cytokine, IL-10. The combination of Rooibos and RPO was associated with enhanced endogenous production of myocardial IL-10 in LPS-induced rats. The results of this study indicate that RPO and Rooibos when supplemented individually showed anti-inflammatory effect at systemic level while their combination exhibited an enhanced anti-inflammatory effect in the myocardial tissue. Therefore, the findings in the current study argue that the combination of these two natural food substances could be beneficial in clinically relevant conditions where inflammation plays a role.
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amelioration of lipopolysaccharide induced liver injury by aqueous Rooibos aspalathus linearis extract via inhibition of pro inflammatory cytokines and oxidative stress
2014Co-Authors: Oluwafemi Omoniyi Oguntibeju, Olawale Razaq Ajuwon, Jeanine L. MarnewickAbstract:Acute liver injury occur after intraperitoneal administration of lipopolysaccharide (LPS). Oxidative stress and release of pro-inflammatory cytokines are both implicated in the pathogenesis of LPS-induced acute liver injury. This study investigated the ameliorative effect of fermented Rooibos (Aspalathus linearis) extract on LPS-induced acute liver injury. Major phenolic compounds in the fermented Rooibos extract by HPLC-DAD, as well as the in vitro antioxidant capacity were quantified before the start of the experiment. Male Wistar rats were randomized into 4 groups (n = 10 per group) and given either water or fermented Rooibos extract for 4 weeks before LPS injection. Hepatic function markers, including aminotransferases and lactate dehydrogenase, lipid peroxidation markers, antioxidant enzymes, glutathione redox status, as well as cytokine levels were monitored in the rats. Injection of LPS significantly increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH). Oxidative stress, evidenced by increased thiobarbituric acid reactive substances (TBARS) measured as malondialdehyde (MDA) in plasma and liver, and decreased glutathione redox status (GSH: GSSG ratio) in whole blood and liver was induced in LPS-challenged rats. Furthermore, hepatic levels of pro-inflammatory response markers TNF-α, IL-1β and IL-6 were increased significantly. Pre-feeding the fermented Rooibos extract for 4 weeks decreased LPS-induced elevated levels of serum AST and LDH (significantly, p < 0.05) as well as ALT marginally. Consuming Rooibos caused an attenuation of the observed increase in plasma and hepatic MDA, decrease in whole blood and liver GSH:GSSG ratio, as well as the changes noted in various antioxidant enzymes. The elevation in TNF-α and IL-6 was significantly suppressed, indicating an inhibition of the induced inflammatory response by Rooibos. Overall, our data showed that aqueous Rooibos extract attenuated LPS-induced liver injury possibly by modulating oxidative stress and suppressing pro-inflammatory cytokines formation.
Dalene De Beer - One of the best experts on this subject based on the ideXlab platform.
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Effect of fermented and green Aspalathus linearis extract loaded hydrogel on surgical wound healing in Sprague Dawley rats
2020Co-Authors: Rukayat D Elegbede, Elizabeth Joubert, Dalene De Beer, T Koekemoer, Margaret O. Ilomuanya, Abimbola Sowemimo, Amarachi Nneji, Maryna Van De VenterAbstract:Abstract Background Aspalathus linearis (Rooibos) has been reported to have a high content of phenolic compounds which elicit antioxidant and anti-inflammatory activity in biological systems. In the present study, we evaluated the effects of “fermented” (oxidised) and green Rooibos extracts embedded in gentamicin loaded acrylate copolymer based hydrogels on inflammatory response in surgical wounds in vivo. Method The major phenolic compounds and a phenolic precursor present in the Rooibos extracts were quantified by HPLC. Acute toxicity of the extracts in Swiss albino mice was evaluated up to 1 g/kg body weight. A modification of free radical initial polymerisation of the alkyl acrylate polymer was utilised to formulate hydrogels loaded with different concentrations of the extracts. The hydrogels were evaluated for swelling, skin irritancy, gel index and pH. Surgical wounds were inflicted on 40 healthy male Sprague Dawley rats, randomly designated to groups treated with the extract loaded hydrogels, hydrogel (without extract; control) and 1% framycetin sulphate containing gauze (positive control). In vivo wound healing test post-surgical intervention was carried out following histomorphometric studies. Results All extract loaded hydrogels shortened the time taken for complete wound closure compared to the control. Hydrogels loaded with fermented Rooibos extract performed better than those loaded with green Rooibos extract or the positive control by significantly (p Conclusion Therapeutic properties of green and fermented Rooibos extract loaded hydrogels have been established in vivo, with the best wound healing indices shown by the hydrogels containing fermented Rooibos extract. This is possibly a result of a shorter inflammatory phase resulting in quicker wound closure and reduced fibrosis.
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Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea
2019Co-Authors: Elisabetta Damiani, Elizabeth Joubert, Dalene De Beer, Patricia Carloni, Gabriele Rocchetti, Biancamaria Senizza, Luca Tiano, Luigi LuciniAbstract:Consumption of Rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the (poly) phenolic profile and in vitro antioxidant capacity of infusions prepared from red (‘fermented’, oxidized) and green (‘unfermented’, unoxidized) Rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both Rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green Rooibos and boiled-brewed red Rooibos. However, boiling green and red Rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of Rooibos tea.
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revisiting the caffeine free status of Rooibos and honeybush herbal teas using specific mrm and high resolution lc ms methods
2019Co-Authors: Maria A. Stander, Elizabeth Joubert, Dalene De BeerAbstract:Abstract Two endemic South African herbal teas, namely Rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.), are especially valued for their caffeine-free status. No recent evidence based on state-of-the-art analytical methodology with low limits of detection (e.g. below 1 μg/L) is available. The current study provides such evidence. Randomly selected samples of fermented Rooibos (n = 10) and honeybush herbal teas from four species (n = 10 each), namely C. intermedia, C. subternata, C. genistoides and C. longifolia, were analysed and no caffeine detected. Similarly, no caffeine was detected in green Rooibos and C. genistoides herbal teas (n = 10 each) indicating that it is absent in the plant. Method specificity was shown to be important since peaks with molecular ion [M+H]+ and product ions resembling those of caffeine were detected, although the retention time and accurate mass did not match those of an authentic reference standard for caffeine.
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Aspalathin from Rooibos (Aspalathus linearis): A Bioactive C-glucosyl Dihydrochalcone with Potential to Target the Metabolic Syndrome.
2018Co-Authors: Rabia Johnson, Daneel Ferreira, Dalene De Beer, Christo J. F. Muller, Phiwayinkosi V. Dludla, Elizabeth JoubertAbstract:Aspalathin is a C-glucosyl dihydrochalcone that is abundantly present in Aspalathus linearis. This endemic South African plant, belonging to the Cape Floristic region, is normally used for production of Rooibos, a herbal tea. Aspalathin was valued initially only as precursor in the formation of the characteristic red-brown colour of “fermented” Rooibos, but the hype about the potential role of natural antioxidants to alleviate oxidative stress, shifted interest in aspalathin to its antioxidant properties and subsequently, its potential role to improve metabolic syndrome, a disease condition interrelated with oxidative stress. The potential use of aspalathin or aspalathin-rich Rooibos extracts as a condition-specific nutraceutical is hampered by the limited supply of green Rooibos (i.e., “unfermented” plant material) and low levels in “fermented” Rooibos, providing incentive for its synthesis. In vitro and in vivo studies relating to the metabolic activity of aspalathin are discussed and cellular mechanisms by which aspalathin improves glucose and lipid metabolism are proposed. Other aspects covered in this review, which are relevant in view of the potential use of aspalathin as an adjunctive therapy, include its poor stability and bioavailability, as well as potential adverse herb-drug interactions, in particular interference with the metabolism of certain commonly prescribed chronic medications for hyperglycaemia and dyslipidaemia.
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production of dihydrochalcone rich green Rooibos aspalathus linearis extract taking into account seasonal and batch to batch variation in phenolic composition of plant material
2017Co-Authors: Dalene De Beer, Neil Miller, Elizabeth JoubertAbstract:Abstract Randomly selected Rooibos plants from three plantations were harvested (a few branches per plant) at intervals from early summer to late spring. The aspalathin and nothofagin content of the plant material was highest at the first harvest date (3.76% and 0.54%, respectively) in summer whereafter their content decreased gradually to the lowest levels in winter and increased to 3.31% and 0.36%, respectively in mid-spring. Commercial green Rooibos production batches ( n = 47), produced over a period of 49 days (end of January until mid-March) from plant material harvested from one plantation were analysed to provide further insight into expected batch-to-batch variation in aspalathin, nothofagin, orientin and iso-orientin content. The aspalathin content of green Rooibos varied between 2.50% and 4.49%, even though the plant material was harvested from the same plantation. The other compounds were present in the plant material in much lower quantities (
W C A Gelderblom - One of the best experts on this subject based on the ideXlab platform.
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Rooibos aspalathus linearis honeybush cyclopia intermedia and cancer bush sutherlandia frutescens subsp microphylla protect against tobacco specific mutagenesis in vitro
2017Co-Authors: Elizabeth Joubert, Christiaan J. Malherbe, W C A Gelderblom, K Gamieldien, L Sissing, G MaritzAbstract:Abstract Antimutagenesis studies against the tobacco-specific mutagens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-oxide, 4 (methyl-nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), were conducted using hot water aqueous extracts of Rooibos ( Aspalathus linearis ), honeybush ( Cyclopia intermedia ), and cancer bush ( Sutherlandia frutescens ). Aqueous extracts of both “fermented” and “unfermented” (green) Rooibos and honeybush were included, while extracts of green and black teas ( Camellia sinensis ) served as benchmarks. A polyphenol-enriched methanol extract of unfermented Rooibos (RgM) was included to further elucidate the possible role of Rooibos polyphenols. Studies were performed in the presence of the metabolic activation against Salmonella typhimurium tester strain TA1535, using the standard plate incorporation and micro-suspension, pre-incubation assays. The mutagenic effects of NNK against the strain TA1535 was best demonstrated using the standard plate incorporation assay, while a higher mutagenicity was demonstrated for NNAL using the micro-suspension, pre-incubation method. Black tea and RgM exhibited the highest protection against NNK-induced mutagenesis followed by the aqueous extracts of Rooibos ≥ green tea ≥ honeybush ≥ cancer bush. Black tea, green tea, RgM and unfermented Rooibos were the most effective against NNAL-induced mutagenesis, followed by fermented Rooibos. The two honeybush extracts exhibited similar, but the weakest protective response. When considering the amount of total polyphenols (TPP) incorporated in the plate incorporation assay, cancer bush exhibited similar protection to that of fermented and unfermented honeybush against NNK mutagenesis. The involvement of specific polyphenol-cytochrome P450 (CYP450) interactions is likely to be involved in the protection against tobacco-related mutagenesis. Polyphenol constituents of Rooibos, honeybush and cancer bush could play an important role in the protection against mutagenesis induced by the major tobacco-specific carcinogens.
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the influence of aspalathus linearis Rooibos and dihydrochalcones on adrenal steroidogenesis quantification of steroid intermediates and end products in h295r cells
2012Co-Authors: Lindie Schloms, Pieter Swart, W C A Gelderblom, Karl-heinz Storbeck, Amanda C. SwartAbstract:Abstract The steroid hormone output of the adrenal gland is crucial in the maintenance of hormonal homeostasis, with hormonal imbalances being associated with numerous clinical conditions which include, amongst others, hypertension, metabolic syndrome, cardiovascular disease, insulin resistance and type 2 diabetes. Aspalathus linearis (Rooibos), which has been reported to aid stress-related symptoms linked to metabolic diseases, contains a wide spectrum of bioactive phenolic compounds of which aspalathin is unique. In this study the inhibitory effects of Rooibos and the dihydrochalcones, aspalathin and nothofagin, were investigated on adrenal steroidogenesis. The activities of both cytochrome P450 17α-hydroxylase/17,20 lyase and cytochrome P450 21-hydroxylase were significantly inhibited in COS-1 cells. In order to study the effect of these compounds in H295R cells, a human adrenal carcinoma cell line, a novel UPLC–MS/MS method was developed for the detection and quantification of twenty-one steroid metabolites using a single chromatographic separation. Under both basal and forskolin-stimulated conditions, the total amount of steroids produced in H295R cells significantly decreased in the presence of Rooibos, aspalathin and nothofagin. Under stimulated conditions, Rooibos decreased the total steroid output 4-fold and resulted in a significant reduction of aldosterone and cortisol precursors. Dehydroepiandrosterone-sulfate levels were unchanged, while the levels of androstenedione (A4) and 11β-hydroxyandrostenedione (11βOH-A4) were inhibited 5.5 and 2.3-fold, respectively. Quantification of 11βOH-A4 showed this metabolite to be a major product of steroidogenesis in H295R cells and we confirm, for the first time, that this steroid metabolite is the product of the hydroxylation of A4 by human cytochrome P450 11β-hydroxylase. Taken together our results demonstrate that Rooibos, aspalathin and nothofagin influence steroid hormone biosynthesis and the flux through the mineralocorticoid, glucocorticoid and androgen pathways, thus possibly contributing to the alleviation of negative effects arising from elevated glucocorticoid levels.
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a comparative study on the antimutagenic properties of aqueous extracts of aspalathus linearis Rooibos different cyclopia spp honeybush and camellia sinensis teas
2006Co-Authors: J D Van Der Merwe, Elizabeth Joubert, Jeanine L. Marnewick, Marena Manley, E S Richards, Petra W Snijman, W C A GelderblomAbstract:Antimutagenic activity of aqueous extracts of the South African herbal teas, Aspalathus linearis (Rooibos) and Cyclopia spp. (honeybush) was compared with that of Camellia sinensis (black, oolong and green) teas in the Salmonella mutagenicity assay using aflatoxin B(1) (AFB(1)) and 2-acetylaminofluorene (2-AAF) as mutagens. The present study presents the first investigation on antimutagenic properties of C. subternata, C. genistoides and C. sessiliflora. The herbal teas demonstrated protection against both mutagens in the presence of metabolic activation, with the exception of "unfermented" (green/unoxidised) C. genistoides against 2-AAF, which either protected or enhanced mutagenesis depending on the concentration. Antimutagenic activity of "fermented" (oxidised) Rooibos was significantly (P 0.05) to that of oolong and green teas. Antimutagenic activity of unfermented C. intermedia and C. subternata exhibited a similar protection as fermented Rooibos against AFB(1). Against 2-AAF, fermented Rooibos exhibited similar protective properties than unfermented C. intermedia and C. sessiliflora. Unfermented Rooibos was less effective than the C. sinensis teas and fermented Rooibos, but had similar (P>0.05) antimutagenicity to that of fermented C. sessiliflora against AFB(1) and fermented C. subternata against 2-AAF. Fermented C. intermedia and C. genistoides exhibited the lowest protective effect against 2-AAF, while fermented C. intermedia exhibited the lowest protection when utilising AFB(1) as mutagen. Aspalathin and mangiferin, major polyphenols in Rooibos and Cyclopia spp., respectively, exhibited weak to moderate protective effects when compared to the major green tea catechin, (-)epigallocatechin gallate (EGCG). Antimutagenic activity of selected herbal tea phenolic compounds indicated that they contribute towards (i) observed antimutagenic activity of the aqueous extracts against both mutagens and (ii) enhancement of the mutagenicity of 2-AAF by unfermented C. genistoides. Antimutagenic activity of the South African herbal teas was mutagen-specific, affected by fermentation and plant material, presumably due to changes and variation in phenolic composition.
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modulation of hepatic drug metabolizing enzymes and oxidative status by Rooibos aspalathus linearis and honeybush cyclopia intermedia green and black camellia sinensis teas in rats
2003Co-Authors: Jeanine L. Marnewick, Elizabeth Joubert, Pieter Swart, Francois H Van Der Westhuizen, W C A GelderblomAbstract:Rooibos and honeybush teas significantly (P < 0.05) enhanced the activity of cytosolic glutathione S-transferase alpha. A significant (P < 0.05) to marginal (P < 0.1) increase in the activity of the microsomal UDP-glucuronosyl transferase was obtained with unprocessed Rooibos and honeybush teas, respectively. Oxidized glutathione (GSSG) levels were significantly (P < 0.05) reduced in the liver of all tea treated rats while reduced glutathione (GSH) was markedly increased in the liver of the herbal tea treated rats. These changes resulted in a significant (P < 0.05) increase in the GSH/ GSSG ratio by the unprocessed, processed Rooibos and unprocessed honeybush teas. Green and black teas markedly to significantly decreased the oxygen radical absorbance capacity in liver homogenates, respectively. Modulation of phase II drug metabolizing enzymes and oxidative status in the liver may be important events in the protection against adverse effects related to mutagenesis and oxidative damage.
Pieter Swart - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Chemopreventive Properties of Green Tea, Rooibos and Honeybush Extracts in Skin Cells
2016Co-Authors: Tandeka U. Magcwebeba, Elizabeth Joubert, Sonja Swanevelder, Pieter Swart, Wentzel C. A. GelderblomAbstract:The chemopreventive properties of the herbal teas Rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) have been demonstrated on mouse skin in vivo but the underlying mechanisms are not clear. The aim of the current study was to determine the anti-proliferative and pro-apoptotic activity of methanol and aqueous extracts of Rooibos and two Cyclopia species in different skin cells, using green tea (Camellia sinensis) as a benchmark. Extracts were also characterised for their major individual polyphenols by high performance liquid chromatography and spectroscopically for the total polyphenol (TP) groups. The methanol extract of Rooibos, containing higher levels of polyphenols than its aqueous extract, displayed similar activity to green tea as it selectively targeted premalignant cells by inhibiting cell proliferation at lower concentrations whilst inducing apoptosis via membrane depolarisation at higher concentrations. Specific roles of the major Rooibos dihydrochalcones and flavanol/proanthocyanidin-type (FLAVA) compounds are likely to be involved. The aqueous extracts of the Cyclopia species were more active against cell proliferation and at inducing apoptosis which was associated with a higher FLAVA content and a reduced TP/FLAVA ratio. In contrast, their methanol extracts exhibited a cytoprotective effect against apoptosis which was related to their monomeric xanthone and flavanone content. The underlying chemopreventive properties of green tea and the herbal teas appear to be associated with diverse and complex monomeric/polymeric polyphenolic cell interactions
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Rooibos influences glucocorticoid levels and steroid ratios in vivo and in vitro a natural approach in the management of stress and metabolic disorders
2014Co-Authors: Lindie Schloms, Jeanine L. Marnewick, Pieter Swart, Carine Smith, Karl-heinz Storbeck, Amanda C. SwartAbstract:cope To determine the effect of Rooibos (Aspalathus linearis) on glucocorticoid biosynthesis and inactivation in vivo and in vitro. Methods and results Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analyses of in vivo studies showed that human Rooibos consumption increased cortisone plasma levels in males (p = 0.0465) and reduced cortisol:cortisone ratios in males and females (p = 0.0486) at risk for cardiovascular disease. In rats, corticosterone (CORT) (p = 0.0275) and deoxycorticosterone (p = 0.0298) levels as well as the CORT:testosterone ratio (p = 0.0009) decreased following Rooibos consumption. The inactivation of cortisol was investigated in vitro by expressing 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) and type 2 (11βHSD2) in CHO-K1 cells. Rooibos inhibited 11βHSD1, which resulted in a significant reduction in the cortisol:cortisone ratio (p < 0.01). No significant effect was detected on 11βHSD2. In vitro studies in adrenal H295R cells showed that Rooibos and rutin, one of the more stable flavonoid compounds present in Rooibos, significantly reduced the levels of cortisol and CORT in cells stimulated with forskolin to mimic a stress response. Conclusion In vivo studies demonstrate that Rooibos significantly decreased glucocorticoid levels in rats and steroid metabolite ratios linked to metabolic disorders—cortisol:cortisone in humans and CORT:testosterone in rats. Results obtained at cellular level elucidate possible mechanisms by which these effects were achieved.
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the influence of aspalathus linearis Rooibos and dihydrochalcones on adrenal steroidogenesis quantification of steroid intermediates and end products in h295r cells
2012Co-Authors: Lindie Schloms, Pieter Swart, W C A Gelderblom, Karl-heinz Storbeck, Amanda C. SwartAbstract:Abstract The steroid hormone output of the adrenal gland is crucial in the maintenance of hormonal homeostasis, with hormonal imbalances being associated with numerous clinical conditions which include, amongst others, hypertension, metabolic syndrome, cardiovascular disease, insulin resistance and type 2 diabetes. Aspalathus linearis (Rooibos), which has been reported to aid stress-related symptoms linked to metabolic diseases, contains a wide spectrum of bioactive phenolic compounds of which aspalathin is unique. In this study the inhibitory effects of Rooibos and the dihydrochalcones, aspalathin and nothofagin, were investigated on adrenal steroidogenesis. The activities of both cytochrome P450 17α-hydroxylase/17,20 lyase and cytochrome P450 21-hydroxylase were significantly inhibited in COS-1 cells. In order to study the effect of these compounds in H295R cells, a human adrenal carcinoma cell line, a novel UPLC–MS/MS method was developed for the detection and quantification of twenty-one steroid metabolites using a single chromatographic separation. Under both basal and forskolin-stimulated conditions, the total amount of steroids produced in H295R cells significantly decreased in the presence of Rooibos, aspalathin and nothofagin. Under stimulated conditions, Rooibos decreased the total steroid output 4-fold and resulted in a significant reduction of aldosterone and cortisol precursors. Dehydroepiandrosterone-sulfate levels were unchanged, while the levels of androstenedione (A4) and 11β-hydroxyandrostenedione (11βOH-A4) were inhibited 5.5 and 2.3-fold, respectively. Quantification of 11βOH-A4 showed this metabolite to be a major product of steroidogenesis in H295R cells and we confirm, for the first time, that this steroid metabolite is the product of the hydroxylation of A4 by human cytochrome P450 11β-hydroxylase. Taken together our results demonstrate that Rooibos, aspalathin and nothofagin influence steroid hormone biosynthesis and the flux through the mineralocorticoid, glucocorticoid and androgen pathways, thus possibly contributing to the alleviation of negative effects arising from elevated glucocorticoid levels.
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inhibition of tumour promotion in mouse skin by extracts of Rooibos aspalathus linearis and honeybush cyclopia intermedia unique south african herbal teas
2005Co-Authors: Jeanine L. Marnewick, Elizabeth Joubert, Shamiel Joseph, Sonja Swanevelder, Pieter SwartAbstract:The modulating effect of ethanol/acetone (E/A) soluble fractions, prepared from methanolic extracts of processed and unprocessed Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) as well as green (Camellia sinensis) teas was established in a two-stage mouse skin carcinogenesis assay. Topical application of the tea fractions prior to the tumour promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), on ICR mouse skin initiated with 7,12-dimethylbenz[a]anthracene (DMBA) suppressed skin tumorigenesis significantly (P<0.001) with the green tea E/A fraction exhibiting a 100% inhibition, unprocessed honeybush 90%, processed honeybush 84.2%, processed Rooibos 75% and unprocessed Rooibos 60%. The green tea fraction, with the highest flavanol/proanthocyanidin content, also exhibited the highest protective activity (99%) against hepatic microsomal lipid peroxidation, and completely inhibited skin tumour formation. Differences in the flavanol/proanthocyanidin and flavonol/flavone composition and/or non polyphenolic constituents are likely to be important determinants in the inhibition of tumour promotion by the herbal tea E/A fractions in mouse skin.
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modulation of hepatic drug metabolizing enzymes and oxidative status by Rooibos aspalathus linearis and honeybush cyclopia intermedia green and black camellia sinensis teas in rats
2003Co-Authors: Jeanine L. Marnewick, Elizabeth Joubert, Pieter Swart, Francois H Van Der Westhuizen, W C A GelderblomAbstract:Rooibos and honeybush teas significantly (P < 0.05) enhanced the activity of cytosolic glutathione S-transferase alpha. A significant (P < 0.05) to marginal (P < 0.1) increase in the activity of the microsomal UDP-glucuronosyl transferase was obtained with unprocessed Rooibos and honeybush teas, respectively. Oxidized glutathione (GSSG) levels were significantly (P < 0.05) reduced in the liver of all tea treated rats while reduced glutathione (GSH) was markedly increased in the liver of the herbal tea treated rats. These changes resulted in a significant (P < 0.05) increase in the GSH/ GSSG ratio by the unprocessed, processed Rooibos and unprocessed honeybush teas. Green and black teas markedly to significantly decreased the oxygen radical absorbance capacity in liver homogenates, respectively. Modulation of phase II drug metabolizing enzymes and oxidative status in the liver may be important events in the protection against adverse effects related to mutagenesis and oxidative damage.
