The Experts below are selected from a list of 1080 Experts worldwide ranked by ideXlab platform
Elizabeth Joubert - One of the best experts on this subject based on the ideXlab platform.
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Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea
Antioxidants, 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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Aspalathin from Rooibos (Aspalathus linearis): A Bioactive C-glucosyl Dihydrochalcone with Potential to Target the Metabolic Syndrome.
Planta Medica, 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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effects of fermented rooibos Aspalathus linearis on adipocyte differentiation
Phytomedicine, 2014Co-Authors: Micheline Sanderson, Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Carmen Pheiffer, Johan Louw, Christo J. F. MullerAbstract:Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including flavonoids, considered to be largely responsible for its health promoting effects, including combatting obesity. The purpose of this study was to examine the effect of fermented rooibos hot water soluble solids on in vitro adipocyte differentiation by using differentiating 3T3-L1 adipocytes. Hot water soluble solids were obtained when preparing an infusion of fermented rooibos at "cup-of-tea" strength. The major phenolic compounds (>5 mg/g) were isoorientin, orientin, quercetin-3-O-robinobioside and enolic phenylpyruvic acid-2-O-β-D-glucoside. Treatment of 3T3-L1 adipocytes with 10 μg/ml and 100 μg/ml of the rooibos soluble solids inhibited intracellular lipid accumulation by 22% (p<0.01) and 15% (p<0.05), respectively. Inhibition of adipogenesis was accompanied by decreased messenger RNA (mRNA) expression of PPARγ, PPARα, SREBF1 and FASN. Western blot analysis exhibited decreased PPARα, SREBF1 and AMPK protein expression. Impeded glycerol release into the culture medium was observed after rooibos treatment. None of the concentrations of rooibos hot water soluble solids was cytotoxic, in terms of ATP content. Interestingly, the higher concentration of hot water soluble solids increased ATP concentrations which were associated with increased basal glucose uptake. Decreased leptin secretion was observed after rooibos treatment. Our data show that hot water soluble solids from fermented rooibos inhibit adipogenesis and affect adipocyte metabolism, suggesting its potential in preventing obesity.
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Effects of fermented rooibos (Aspalathus linearis) on adipocyte differentiation.
Phytomedicine, 2013Co-Authors: Micheline Sanderson, Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Carmen Pheiffer, Johan Louw, Christo J. F. MullerAbstract:Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including flavonoids, considered to be largely responsible for its health promoting effects, including combatting obesity. The purpose of this study was to examine the effect of fermented rooibos hot water soluble solids on in vitro adipocyte differentiation by using differentiating 3T3-L1 adipocytes. Hot water soluble solids were obtained when preparing an infusion of fermented rooibos at "cup-of-tea" strength. The major phenolic compounds (>5 mg/g) were isoorientin, orientin, quercetin-3-O-robinobioside and enolic phenylpyruvic acid-2-O-β-D-glucoside. Treatment of 3T3-L1 adipocytes with 10 μg/ml and 100 μg/ml of the rooibos soluble solids inhibited intracellular lipid accumulation by 22% (p
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amelioration of palmitate induced insulin resistance in c2c12 muscle cells by rooibos Aspalathus linearis
Phytomedicine, 2013Co-Authors: Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Christo J. F. Muller, Andy R Opoku, Johan LouwAbstract:Abstract Increased levels of free fatty acids (FFAs), specifically saturated free fatty acids such as palmitate are associated with insulin resistance of muscle, fat and liver. Skeletal muscle, responsible for up to 80% of the glucose disposal from the peripheral circulation, is particularly vulnerable to increased levels of saturated FFAs. Rooibos ( Aspalathus linearis ) and its unique dihydrochalcone C -glucoside, aspalathin, shown to reduce hyperglycemia in diabetic rats, could play a role in preventing or ameliorating the development of insulin resistance. This study aims to establish whether rooibos can ameliorate experimentally-induced insulin-resistance in C2C12 skeletal muscle cells. Palmitate-induced insulin resistant C2C12 cells were treated with an aspalathin-enriched green (unfermented) rooibos extract (GRE), previously shown for its blood glucose lowering effect in vitro and in vivo or an aqueous extract of fermented rooibos (FRE). Glucose uptake and mitochondrial activity were measured using 2-deoxy-[ 3 H]- d -glucose, MTT and ATP assays, respectively. Expression of proteins relevant to glucose metabolism was analysed by Western blot. GRE contained higher levels of all compounds, except the enolic phenylpyruvic acid-2 -O- glucoside and luteolin-7- O -glucoside. Both rooibos extracts increased glucose uptake, mitochondrial activity and ATP production. Compared to FRE, GRE was more effective at increasing glucose uptake and ATP production. At a mechanistic level both extracts down-regulated PKC θ activation, which is associated with palmitate-induced insulin resistance. Furthermore, the extracts increased activation of key regulatory proteins (AKT and AMPK) involved in insulin-dependent and non-insulin regulated signalling pathways. Protein levels of the glucose transporter (GLUT4) involved in glucose transport via these two pathways were also increased. This in vitro study therefore confirms that rooibos can ameliorate palmitate-induced insulin resistance in C2C12 skeletal muscle cells. Inhibition of PKC θ activation and increased activation of AMPK and AKT offer a plausible mechanistic explanation for this ameliorative effect.
Dalene De Beer - One of the best experts on this subject based on the ideXlab platform.
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Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea
Antioxidants, 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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Aspalathin from Rooibos (Aspalathus linearis): A Bioactive C-glucosyl Dihydrochalcone with Potential to Target the Metabolic Syndrome.
Planta Medica, 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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effects of fermented rooibos Aspalathus linearis on adipocyte differentiation
Phytomedicine, 2014Co-Authors: Micheline Sanderson, Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Carmen Pheiffer, Johan Louw, Christo J. F. MullerAbstract:Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including flavonoids, considered to be largely responsible for its health promoting effects, including combatting obesity. The purpose of this study was to examine the effect of fermented rooibos hot water soluble solids on in vitro adipocyte differentiation by using differentiating 3T3-L1 adipocytes. Hot water soluble solids were obtained when preparing an infusion of fermented rooibos at "cup-of-tea" strength. The major phenolic compounds (>5 mg/g) were isoorientin, orientin, quercetin-3-O-robinobioside and enolic phenylpyruvic acid-2-O-β-D-glucoside. Treatment of 3T3-L1 adipocytes with 10 μg/ml and 100 μg/ml of the rooibos soluble solids inhibited intracellular lipid accumulation by 22% (p<0.01) and 15% (p<0.05), respectively. Inhibition of adipogenesis was accompanied by decreased messenger RNA (mRNA) expression of PPARγ, PPARα, SREBF1 and FASN. Western blot analysis exhibited decreased PPARα, SREBF1 and AMPK protein expression. Impeded glycerol release into the culture medium was observed after rooibos treatment. None of the concentrations of rooibos hot water soluble solids was cytotoxic, in terms of ATP content. Interestingly, the higher concentration of hot water soluble solids increased ATP concentrations which were associated with increased basal glucose uptake. Decreased leptin secretion was observed after rooibos treatment. Our data show that hot water soluble solids from fermented rooibos inhibit adipogenesis and affect adipocyte metabolism, suggesting its potential in preventing obesity.
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Effects of fermented rooibos (Aspalathus linearis) on adipocyte differentiation.
Phytomedicine, 2013Co-Authors: Micheline Sanderson, Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Carmen Pheiffer, Johan Louw, Christo J. F. MullerAbstract:Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including flavonoids, considered to be largely responsible for its health promoting effects, including combatting obesity. The purpose of this study was to examine the effect of fermented rooibos hot water soluble solids on in vitro adipocyte differentiation by using differentiating 3T3-L1 adipocytes. Hot water soluble solids were obtained when preparing an infusion of fermented rooibos at "cup-of-tea" strength. The major phenolic compounds (>5 mg/g) were isoorientin, orientin, quercetin-3-O-robinobioside and enolic phenylpyruvic acid-2-O-β-D-glucoside. Treatment of 3T3-L1 adipocytes with 10 μg/ml and 100 μg/ml of the rooibos soluble solids inhibited intracellular lipid accumulation by 22% (p
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amelioration of palmitate induced insulin resistance in c2c12 muscle cells by rooibos Aspalathus linearis
Phytomedicine, 2013Co-Authors: Elizabeth Joubert, Sithandiwe E. Mazibuko, Dalene De Beer, Rabia Johnson, Christo J. F. Muller, Andy R Opoku, Johan LouwAbstract:Abstract Increased levels of free fatty acids (FFAs), specifically saturated free fatty acids such as palmitate are associated with insulin resistance of muscle, fat and liver. Skeletal muscle, responsible for up to 80% of the glucose disposal from the peripheral circulation, is particularly vulnerable to increased levels of saturated FFAs. Rooibos ( Aspalathus linearis ) and its unique dihydrochalcone C -glucoside, aspalathin, shown to reduce hyperglycemia in diabetic rats, could play a role in preventing or ameliorating the development of insulin resistance. This study aims to establish whether rooibos can ameliorate experimentally-induced insulin-resistance in C2C12 skeletal muscle cells. Palmitate-induced insulin resistant C2C12 cells were treated with an aspalathin-enriched green (unfermented) rooibos extract (GRE), previously shown for its blood glucose lowering effect in vitro and in vivo or an aqueous extract of fermented rooibos (FRE). Glucose uptake and mitochondrial activity were measured using 2-deoxy-[ 3 H]- d -glucose, MTT and ATP assays, respectively. Expression of proteins relevant to glucose metabolism was analysed by Western blot. GRE contained higher levels of all compounds, except the enolic phenylpyruvic acid-2 -O- glucoside and luteolin-7- O -glucoside. Both rooibos extracts increased glucose uptake, mitochondrial activity and ATP production. Compared to FRE, GRE was more effective at increasing glucose uptake and ATP production. At a mechanistic level both extracts down-regulated PKC θ activation, which is associated with palmitate-induced insulin resistance. Furthermore, the extracts increased activation of key regulatory proteins (AKT and AMPK) involved in insulin-dependent and non-insulin regulated signalling pathways. Protein levels of the glucose transporter (GLUT4) involved in glucose transport via these two pathways were also increased. This in vitro study therefore confirms that rooibos can ameliorate palmitate-induced insulin resistance in C2C12 skeletal muscle cells. Inhibition of PKC θ activation and increased activation of AMPK and AKT offer a plausible mechanistic explanation for this ameliorative effect.
W C A Gelderblom - One of the best experts on this subject based on the ideXlab platform.
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south african herbal teas Aspalathus linearis cyclopia spp and athrixia phylicoides a review
Journal of Ethnopharmacology, 2008Co-Authors: Elizabeth Joubert, Ann Louw, W C A Gelderblom, Dalene De BeerAbstract:Rooibos (Aspalathus linearis (Brum.f) Dahlg.) and honeybush (Cyclopia Vent. species) are popular indigenous South African herbal teas enjoyed for their taste and aroma. Traditional medicinal uses of rooibos in South Africa include alleviation of infantile colic, allergies, asthma and dermatological problems, while a decoction of honeybush was used as a restorative and as an expectorant in chronic catarrh and pulmonary tuberculosis. Traditional medicinal uses of Athrixia phylicoides DC., or bush tea, another indigenous South African plant with very limited localised use as herbal tea, include treatment of boils, acne, infected wounds and infected throats. Currently rooibos and honeybush are produced for the herbal tea market, while bush tea has potential for commercialisation. A summary of the historical and modern uses, botany, distribution, industry and chemical composition of these herbal teas is presented. A comprehensive discussion of in vitro, ex vivo and in vivo biological properties, required to expand their applications as nutraceutical and cosmeceutical products, is included, with the main emphasis on rooibos. Future research needs include more comprehensive chemical characterisation of extracts, identification of marker compounds for extract standardisation and quality control, bioavailability and identification of bio-markers of dietary exposure, investigation of possible herb-drug interactions and plant improvement with regards to composition and bioactivity.
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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
Cancer Letters, 2005Co-Authors: Jeanine L. Marnewick, Elizabeth Joubert, Shamiel Joseph, Sonja Swanevelder, Pieter Swart, W C A GelderblomAbstract: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.
M Maaza - One of the best experts on this subject based on the ideXlab platform.
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green synthesis of zin tin oxide znsno3 nanoparticles using Aspalathus linearis natural extracts structural morphological optical and electrochemistry study
Applied Surface Science, 2017Co-Authors: Noluthando Mayedwa, Nametso Mongwaketsi, S Khamlich, K Kaviyarasu, N Matinise, M MaazaAbstract:Abstract The biosynthesis of ZnSnO3 nanoparticles via Aspalathus linearis natural extracts is reported in this contribution. Crystallinity of orthorhombic perovskite ZnSnO3 nanoparticles at room temperature and annealed at 300 and 500 °C was investigated by X-ray diffraction. High resolution transmission electron microscope (HRTEM) and high resolution scanning electron microscope (HRSEM) were used for determination of morphology, confirmed the nanoclusters of ZnSnO3 annealed at 500 °C were polycrystalline with an average particle size of 18.5 nm. UV–vis diffused reflectance showed absorption edge at 354 nm and a band gap of 3.50 eV for ZnSnO3 nanoparticles. Raman modes at 482 and 636 cm−1 are distinctive Raman shifts of ZnSnO3 nanoparticles. The other complementary investigations by infrared, thermogravimetry and differential scanning calorimetry were done. Cyclic voltammetry of ZnSnO3 nanoparticles on glassy carbon electron (GCE) showed two redox peaks, oxidation peak at 3.8 V and reduction peak 2.7 V. The reaction was diffusion controlled with a diffusion coefficient of 1.93 × 10−7 cm2 s−1. Electrochemical impedance spectroscopy showed charge transfer resistance of 3.325 × 10−5 and 3.154 × 10−5 Ω showing slight improvements in ionic conductivity with the addition of K3Fe(CN)6 to the KOH electrolyte.
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green synthesis of nickel oxide palladium and palladium oxide synthesized via Aspalathus linearis natural extracts physical properties mechanism of formation
Applied Surface Science, 2017Co-Authors: Noluthando Mayedwa, Nametso Mongwaketsi, S Khamlich, K Kaviyarasu, N Matinise, M MaazaAbstract:Abstract The biosynthesis of PdO and NiO nanoparticles (NPs) via Aspalathus linearis natural extracts as reducing and capping agent and calcinated at 200 and 500 °C. High Resolution Electron Microscope (HRTEM) was used to determine the morphology of PdO NPs exhibited tetragonal and NiO NPs agglomerated quasi spherical shape. The average diameter for PdO NPs is (fparticle) ∼22.7 ± 4.3 nm and NiO NPs is ∼31.8 ± 5 nm. Selected Area Electron Diffraction (SAED) and X-ray diffraction confirmed both nanoparticles are polycrystalline. Mechanism of reaction is proposed and Infrared spectroscopy confirmed the chemical bonding of the natural extract to the NPs, at 451 and 683 cm−1 for Pd and PdO and 481 cm−1 NiO NPs. Cyclic voltammetry showed oxidation peak potential for PdO NPs was 0.5 and 0.64 V and reduction peak at 0.68 V. NiO NPs oxidation peak potential at 0.34, 0.51 and 0.67 V and reduction peak at 0.62 V. Nyquist plot showed the diameter of the semi-circular portion is proportional to the charge transfer resistance with PdO more conductive than NiO nanoparticles. Bode plot showed both NPs are semiconductors with phase angle value of 49.3° for PdO and 50.4° for NiO NPs.
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ruo 2 nanoparticles by a novel green process via Aspalathus linearis natural extract their water splitting response
Journal of Alloys and Compounds, 2016Co-Authors: E. Ismail, A. Diallo, M Maaza, Mohammed Khenfouch, Simon Mokhotjwa DhlaminiAbstract:Abstract This contribution reports on the biosynthesis of quasi-monodisperse rutile Ruthenium (IV) oxide nanoparticles with an average diameter of 2.15 nm using Aspalathus linearis natural extract as a chelating agent as well as a capping compound. Their morphological, structural and optical properties were investigated using various complementary surface/interface characterization techniques. This includes transmission electron microscopy, selective area electron diffraction. Their optical band gap was found to be about 2.1 eV. Loaded onto a p-type Cu 2 O thin film, the nano-scaled RuO 2 –Cu 2 O tandem exhibits an effective water photo-splitting response in the solar spectrum.
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green synthesis of zno nanoparticles by Aspalathus linearis structural optical properties
Journal of Alloys and Compounds, 2015Co-Authors: A. Diallo, Balla D. Ngom, E. Park, M MaazaAbstract:Abstract This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis 's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported.
Jeanine L. Marnewick - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomics of the Rooibos (Aspalathus linearis) Species Complex
BioTech, 2020Co-Authors: Emily Amor Stander, Jeanine L. Marnewick, Wesley Williams, Yamkela Mgwatyu, Peter Van Heusden, Fanie Rautenbach, Marilize Le Roes-hill, Uljana HesseAbstract:Rooibos (Aspalathus linearis), widely known as a herbal tea, is endemic to the Cape Floristic Region of South Africa (SA). It produces a wide range of phenolic compounds that have been associated with diverse health promoting properties of the plant. The species comprises several growth forms that differ in their morphology and biochemical composition, only one of which is cultivated and used commercially. Here, we established methodologies for non-invasive transcriptome research of wild-growing South African plant species, including (1) harvesting and transport of plant material suitable for RNA sequencing; (2) inexpensive, high-throughput biochemical sample screening; (3) extraction of high-quality RNA from recalcitrant, polysaccharide- and polyphenol rich plant material; and (4) biocomputational analysis of Illumina sequencing data, together with the evaluation of programs for transcriptome assembly (Trinity, IDBA-Trans, SOAPdenovo-Trans, CLC), protein prediction, as well as functional and taxonomic transcript annotation. In the process, we established a biochemically characterized sample pool from 44 distinct rooibos ecotypes (1–5 harvests) and generated four in-depth annotated transcriptomes (each comprising on average ≈86,000 transcripts) from rooibos plants that represent distinct growth forms and differ in their biochemical profiles. These resources will serve future rooibos research and plant breeding endeavours.
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Rooibos Aspalathus linearis – Can it reduce the incidence and severity of acute mountain sickness? A case study of Aconcagua (6962 m) climbing expedition, Argentina
Journal of Physical Activity and Health, 2019Co-Authors: Simeon E.h. Davies, Jeanine L. Marnewick, Sacha WestAbstract:Sport and leisure activities at altitude, including climbing, trekking and various snow sports, continue to grow in popularity. However, the increase of high altitude activities is associated with hypoxia and its consequences, namely acute mountain sickness (AMS), which can manifest in two life-threatening conditions, namely high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). The most common methods for dealing with the potential onset of AMS involve acclimatization strategies, such as ascending 500m or less a day, and ingesting prescribed prophylactic medication, which can have adverse side effects. The study focuses on the efficacy of the fynbos plant rooibos Aspalathus linearis to reduce and/or prevent AMS. Rooibos is a unique South African herbal product usually consumed as a tea and a dietary source of unique bio-active antioxidants. A case study was conducted involving eight climbers (mean age: 46.6± 11.2 years) who supplemented their diet with rooibos in capsule form containing ~ 400mg rooibos extract (standardized to include 130mg total polyphenols/capsule) taken 3 times per day during the ascent of Aconcagua (6962 m) in Argentina. The dosage is equivalent to about 6 cups of rooibos tea per day. Daily resting mean heart rate increased from 62 to 87 beats per minutes (bpm) and mean peripheral blood oxygen saturations levels declined from 98% to 79% SpO2. The Lake Louise (LLS) assessment reported negligible symptoms of AMS for seven climbers up to, and at 6000 m. It is tentatively asserted that the findings indicate the potential of the rooibos plant Aspalathus linearis to reduce the symptoms and/or onset of AMS for those persons ascending to high altitudes, whether for sport, leisure or for work.Keywords: Hypoxia, acute mountain sickness (AMS), Rooibos.
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The efficacy of rooibos Aspalathus linearis as an ergogenic aid during exercise
International Journal of Human Factors and Ergonomics, 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
Molecules, 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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Amelioration of lipopolysaccharide-induced liver injury by aqueous rooibos (Aspalathus linearis
BMC Complementary and Alternative Medicine, 2014Co-Authors: Olawale Razaq Ajuwon, Oluwafemi Omoniyi Oguntibeju, 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.