E Joubert

Summary

Affiliation: Onderstepoort Veterinary Institute
Country: South Africa

Publications

  1. ncbi request reprint Phenolic metabolites from honeybush tea (Cyclopia subternata)
    B Irene Kamara
    Department of Chemistry, University of the Free State, P O Box 339, Bloemfontein, 9300 South Africa
    J Agric Food Chem 52:5391-5. 2004
  2. ncbi request reprint Phenolic contribution of South African herbal teas to a healthy diet
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council, Private Bag X5026, Stellenbosch, South Africa 7599
    Nat Prod Commun 4:701-18. 2009
  3. doi request reprint Effect of pre-drying treatments and storage on color and phenolic composition of green honeybush (Cyclopia subternata) herbal tea
    Elizabeth Joubert
    Agricultural Research Council ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 58:338-44. 2010
  4. doi request reprint Occurrence and sensory perception of Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid in rooibos (Aspalathus linearis)
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    Food Chem 136:1078-85. 2013
  5. doi request reprint Variation in phenolic content and antioxidant activity of fermented rooibos herbal tea infusions: role of production season and quality grade
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council ARC, Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 60:9171-9. 2012
  6. ncbi request reprint Evaluation of spectrophotometric methods for screening of green rooibos (Aspalathus linearis) and green honeybush (Cyclopia genistoides) extracts for high levels of Bio-active compounds
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    Phytochem Anal 19:169-78. 2008
  7. doi request reprint South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides--a review
    E Joubert
    Post Harvest and Wine Technology Division, ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Ethnopharmacol 119:376-412. 2008
  8. ncbi request reprint Use of NIRS for quantification of mangiferin and hesperidin contents of dried green honeybush (Cyclopia genistoides) plant material
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    J Agric Food Chem 54:5279-83. 2006
  9. doi request reprint Effect of species variation and processing on phenolic composition and in vitro antioxidant activity of aqueous extracts of Cyclopia spp. (Honeybush Tea)
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    J Agric Food Chem 56:954-63. 2008
  10. ncbi request reprint Antioxidant and pro-oxidant activities of aqueous extracts and crude polyphenolic fractions of rooibos (Aspalathus linearis)
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 53:10260-7. 2005

Collaborators

Detail Information

Publications25

  1. ncbi request reprint Phenolic metabolites from honeybush tea (Cyclopia subternata)
    B Irene Kamara
    Department of Chemistry, University of the Free State, P O Box 339, Bloemfontein, 9300 South Africa
    J Agric Food Chem 52:5391-5. 2004
    ..The structures were elucidated by spectroscopic and spectrometric analysis...
  2. ncbi request reprint Phenolic contribution of South African herbal teas to a healthy diet
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council, Private Bag X5026, Stellenbosch, South Africa 7599
    Nat Prod Commun 4:701-18. 2009
    ..Modulation of drug metabolising enzymes is indicated which not only could affect the therapeutic window of drugs, but also the bioavailability of other dietary flavonoids...
  3. doi request reprint Effect of pre-drying treatments and storage on color and phenolic composition of green honeybush (Cyclopia subternata) herbal tea
    Elizabeth Joubert
    Agricultural Research Council ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 58:338-44. 2010
    ..Storage at 30 degrees C resulted in detrimental color changes, leading to the loss of the green leaf color irrespective of the pre-drying treatment...
  4. doi request reprint Occurrence and sensory perception of Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid in rooibos (Aspalathus linearis)
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    Food Chem 136:1078-85. 2013
    ..This leads to large variation in the fermented plant material, infusions and food-grade extracts. PPAG was shown to have a slightly bitter to astringent taste and a detection threshold of 0.4 mg/l in water...
  5. doi request reprint Variation in phenolic content and antioxidant activity of fermented rooibos herbal tea infusions: role of production season and quality grade
    Elizabeth Joubert
    Post Harvest and Wine Technology Division, Agricultural Research Council ARC, Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 60:9171-9. 2012
    ..Substantial variation was observed in the individual content values of the phenolic compounds and total antioxidant capacity within production seasons and quality grades...
  6. ncbi request reprint Evaluation of spectrophotometric methods for screening of green rooibos (Aspalathus linearis) and green honeybush (Cyclopia genistoides) extracts for high levels of Bio-active compounds
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    Phytochem Anal 19:169-78. 2008
    ..27). The aspalathin content of rooibos extracts correlated with their TAA (r = 0.96), but the mangiferin content of honeybush water extracts only gave a moderate correlation with their TAA (r = 0.75)...
  7. doi request reprint South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides--a review
    E Joubert
    Post Harvest and Wine Technology Division, ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Ethnopharmacol 119:376-412. 2008
    ....
  8. ncbi request reprint Use of NIRS for quantification of mangiferin and hesperidin contents of dried green honeybush (Cyclopia genistoides) plant material
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    J Agric Food Chem 54:5279-83. 2006
    ..46 g/100 g; R2=0.74; and RPD=1.96) and hesperidin (SEP=0.38 g/100 g; R2=0.72; and RDP=1.90) contents of the dried plant material are adequate for screening purposes, based on RPD values...
  9. doi request reprint Effect of species variation and processing on phenolic composition and in vitro antioxidant activity of aqueous extracts of Cyclopia spp. (Honeybush Tea)
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
    J Agric Food Chem 56:954-63. 2008
    ..However, the presence of high levels of mangiferin merits the use of Cyclopia spp. and, in particular, C. genistoides, as an alternative herbal tea and potential dietary supplement...
  10. ncbi request reprint Antioxidant and pro-oxidant activities of aqueous extracts and crude polyphenolic fractions of rooibos (Aspalathus linearis)
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 53:10260-7. 2005
    ..The in vitro pro-oxidant activity displayed by flavonoid-enriched fractions of rooibos demonstrates that one must be aware of the potential adverse biological properties of potent antioxidant extracts utilized as dietary supplements...
  11. doi request reprint Effect of heat on aspalathin, iso-orientin, and orientin contents and color of fermented rooibos (Aspalathus linearis) iced tea
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 57:4204-11. 2009
    ..This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation...
  12. ncbi request reprint A comparative study on the antimutagenic properties of aqueous extracts of Aspalathus linearis (rooibos), different Cyclopia spp. (honeybush) and Camellia sinensis teas
    J D van der Merwe
    Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa
    Mutat Res 611:42-53. 2006
    ..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...
  13. doi request reprint Isolation of isomangiferin from honeybush (Cyclopia subternata) using high-speed counter-current chromatography and high-performance liquid chromatography
    Dalene De Beer
    ARC Infruitec Nietvoorbij, Stellenbosch, South Africa
    J Chromatogr A 1216:4282-9. 2009
    ..The chemical structure of isomangiferin was confirmed by LC-high-resolution electrospray ionization MS, as well as one- and two-dimensional NMR spectroscopy...
  14. doi request reprint Selective extraction of Cyclopia for enhanced in vitro phytoestrogenicity and benchmarking against commercial phytoestrogen extracts
    Ciko Mfenyana
    Department of Biochemistry, University of Stellenbosch, Stellenbosch, South Africa
    J Steroid Biochem Mol Biol 112:74-86. 2008
    ....
  15. ncbi request reprint Microbial content of commercial South African high-moisture dried fruits
    R C Witthuhn
    Department of Food Science, Stellenbosch University, Matieland, South Africa
    J Appl Microbiol 98:722-6. 2005
    ..The aim was to evaluate commercially available South African high-moisture dried fruits (HMDF) for the microbial, moisture and SO2 contents, as well as aw and pH...
  16. ncbi request reprint Unravelling the total antioxidant capacity of pinotage wines: contribution of phenolic compounds
    Dalene De Beer
    Department of Food Science, Stellenbosch University, Private Bag X1, 7602 Matieland, Stellenbosch, South Africa
    J Agric Food Chem 54:2897-905. 2006
    ..This suggests that synergy between phenolic compounds does play a role in the wine TAC but that it does not explain the large discrepancy between measured and calculated TAC values...
  17. ncbi request reprint Rapid measurement and evaluation of the effect of drying conditions on harpagoside content in Harpagophytum procumbens (devil's claw) root
    Elizabeth Joubert
    ARC Infruitec Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
    J Agric Food Chem 53:3493-502. 2005
    ..236%, r = 0.64; for 8rhoCHG: SEP = 0.048%, r = 0.73)...
  18. doi request reprint Enhancement of Rooibos (Aspalathus linearis) aqueous extract and antioxidant yield with fungal enzymes
    Mia Pengilly
    Department of Microbiology, Stellenbosch University, Private Bag XI, Matieland 7602, South Africa
    J Agric Food Chem 56:4047-53. 2008
    ..edodes (cultured in yeast peptone-wheat straw medium) enhanced the release of soluble solids as well as color formation, leading to semifermented rooibos with a relatively high aspalathin content, compared to fermented rooibos...
  19. ncbi request reprint Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols
    Nicolette J D Verhoog
    Department of Biochemistry, Stellenbosch University, Stellenbosch 7600, South Africa
    J Agric Food Chem 55:4371-81. 2007
    ..HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species...
  20. ncbi request reprint In situ flavonoid analysis by FT-Raman spectroscopy: identification, distribution, and quantification of aspalathin in green rooibos (Aspalathus linearis)
    Malgorzata Baranska
    Federal Centre for Breeding Research on Cultivated Plants, Institute of Plant Analysis, Neuer Weg 22 23, D 06484 Quedlinburg, Germany
    Anal Chem 78:7716-21. 2006
    ..Based on the spectral data and reference HPLC values, reliable multivariate calibration models were developed for quantification of aspalathin, nothofagin, and the combined dihydrochalcone contents of dried, green rooibos...
  21. ncbi request reprint Inhibition of tumour promotion in mouse skin by extracts of rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia), unique South African herbal teas
    Jeanine Marnewick
    PROMEC Unit, Medical Research Council, P O Box 19070, Tygerberg 7505, South Africa
    Cancer Lett 224:193-202. 2005
    ....
  22. ncbi request reprint 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
    Jeanine L Marnewick
    PROMEC Unit, Medical Research Council, P O Box 19070, Tygerberg, 7505 South Africa
    J Agric Food Chem 51:8113-9. 2003
    ..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...
  23. ncbi request reprint Polyphenols from Honeybush tea (Cyclopia intermedia)
    B Irene Kamara
    Department of Chemistry, University of the Free State, P O Box 339, Bloemfontein, 9300 South Africa
    J Agric Food Chem 51:3874-9. 2003
    ..intermedia...
  24. ncbi request reprint The antimutagenic activity of the major flavonoids of rooibos (Aspalathus linearis): some dose-response effects on mutagen activation-flavonoid interactions
    Petra W Snijman
    Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
    Mutat Res 631:111-23. 2007
    ..The C ring does not appear to be a prerequisite when comparing for the antimutagenic activity of the dihydrochalcones when compared of the dihydrochalcones with the structural flavone analogues...
  25. ncbi request reprint Antioxidant activity of South African red and white cultivar wines: free radical scavenging
    Dalene De Beer
    Department of Food Science, University of Stellenbosch, Private Bag X1, 7602 Matieland Stellenbosch, South Africa
    J Agric Food Chem 51:902-9. 2003
    ..866) and tartaric acid ester content of white wines (r = 0.767). Canonical discriminant analysis using phenolic composition and antioxidant activity was applied to differentiate between red and white cultivar wines...