Please use this identifier to cite or link to this item: http://hdl.handle.net/11189/6452
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dc.contributor.authorVan der Merwe, JDen_US
dc.contributor.authorDe Beer, Den_US
dc.contributor.authorSwanevelder, Sen_US
dc.contributor.authorJoubert, Een_US
dc.contributor.authorGelderblom, Wentzelen_US
dc.date.accessioned2018-07-12T07:05:16Z-
dc.date.available2018-07-12T07:05:16Z-
dc.date.issued2017-
dc.identifier.citationVan der Merwe, J.D., De Beer, D., Swanevelder, S., Joubert, E. and Gelderblom, W.C.A. 2017. Dietary exposure to honeybush (Cyclopia) polyphenol-enriched extracts altered redox status and expression of oxidative stress and antioxidant defense-related genes in rat liver. South African Journal of Botany, 110: 230-239.en_US
dc.identifier.issn0254-6299-
dc.identifier.urihttp://hdl.handle.net/11189/6452-
dc.description.abstractInterest in Cyclopia spp. (honeybush) as a source material for production of polyphenol-enriched extracts (PEEs) for the food ingredient and nutraceutical markets requires investigation of their safety. PEEs of Cyclopia subternata (PECsub) and Cyclopia genistoides (PECgen) were fed (2.5 g/kg feed) to male Fischer rats for 28 days, while PECsub, having the highest total polyphenol content and antioxidant activity, was also fed for 90 days. Their dietary intake did not significantly (P ≥ 0.05) affect body weight gain or relative liver and kidney weight. PECsub resulted in a significant (P < 0.05) increase in the total serum bilirubin after 28 days, while serum alkaline phosphatase levels were only significantly (P < 0.05) increased after 90 days, suggesting alterations in the biliary system. No effect on serum iron levels was noticed after 28 days, but PECsub significantly (P < 0.05) reduced serum iron after 90 days. Both PECsub and PECgen increased glutathione reductase activity in the liver significantly (P < 0.05) after 28 days. Reduced glutathione (GSH) content was significantly (P < 0.05) decreased after 90 days by PECsub resulting in a marked, but not significant (P ≥ 0.05) decrease in the GSH/GSSG ratio. Considering the expression of oxidative stress and antioxidant defense-related genes after 28 days, the expression of eleven genes was altered by PECsub and PECgen. Seven genes, mutually affected by PECsub and PECgen, included (i) antioxidant-related genes, prostaglandin-endoperoxide synthase 1 (Ptgs1), kinesin family member 9 (Kif9) and serine (or cysteine) peptidase inhibitor clade B member 1b (Serpinb1b); (ii) genes involved in reactive oxygen species (ROS) metabolism, xeroderma pigmentosum complementation group A (Xpa) and thioredoxin interacting protein (Txnip) as well as (iii) oxygen transporter-related genes, Fanconi anemia complementation group C (Fancc) and vimentin (Vim). The expression of NADPH oxidase organiser 1 (Noxo1) increased 19.97-fold by PECsub and the thyroid peroxidase (Tpo) 372-fold by PECgen. Changes in the expression of the oxidative stress and antioxidant defense-related genes could be indicative of an underlying stress effected by the honeybush PEEs in the liver. Differential gene expression could likely be attributed to the differences in phenolic composition of the extracts. The daily dietary intake of total polyphenol and individual phenolic constituents, recalculated to a human equivalent dose, was much higher, especially for C. subternata, than normally consumed when habitually drinking “fermented” honeybush herbal tea. Subsequent studies verifying the protein-associated changes governing the oxidative status in the liver is required.en_US
dc.language.isoenen_US
dc.publisherElsevieren_US
dc.relation.ispartofSouth African Journal of Botanyen_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/3.0/za/-
dc.subjectHoneybushen_US
dc.subjectPolyphenolsen_US
dc.subjectXanthonesen_US
dc.subjectBenzophenonesen_US
dc.subjectRat liveren_US
dc.subjectRedox statusen_US
dc.subjectGene expressionen_US
dc.titleDietary exposure to honeybush (Cyclopia) polyphenol-enriched extracts altered redox status and expression of oxidative stress and antioxidant defense-related genes in rat liveren_US
dc.type.patentArticleen_US
dc.identifier.doihttps://doi.org/10.1016/j.sajb.2016.08.004-
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