title: Short-Term and Sub-Chronic Dietary Exposure to Aspalathin-Enriched Green Rooibos (Aspalathus linearis) Extract Affects Rat Liver Function and Antioxidant Status.
abstract: An aspalathin-enriched green rooibos (Aspalathus linearis) extract (GRE) was fed to male Fischer rats in two independent studies for 28 and 90 days. The average dietary total polyphenol (TP) intake was 756 and 627 mg Gallic acid equivalents (GAE)/kg body weight (bw)/day over 28 and 90 days, respectively, equaling human equivalent doses (HEDs) of 123 and 102 GAE mg/kg bw/day. Aspalathin intake of 295 mg/kg bw/day represents a HED of 48 mg/kg bw/day (90 day study). Consumption of GRE increased feed intake significantly (p < 0.05) compared to the control after 90 days, but no effect on body and organ weight parameters was observed. GRE significantly (p < 0.05) reduced serum total cholesterol and iron levels, whilst significantly (p < 0.05) increasing alkaline phosphatase enzyme activity after 90 days. Endogenous antioxidant enzyme activity in the liver, i.e., catalase and superoxide dismutase activity, was not adversely affected. Glutathione reductase activity significantly (p < 0.05) increased after 28 days, while glutathione (GSH) content was decreased after 90 days, suggesting an altered glutathione redox cycle. Quantitative Real Time polymerase chain reaction (PCR) analysis showed altered expression of certain antioxidant defense and oxidative stress related genes, indicative, among others, of an underlying oxidative stress related to changes in the GSH redox pathway and possible biliary dysfunction.
authors.affiliation: Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa. debora@factssa.com.
authors.forename: Johanna Debora
authors.initials: JD
authors.lastname: van der Merwe
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa. DBeerD@arc.agric.za.
authors.forename: Dalene
authors.initials: D
authors.lastname: de Beer
authors.affiliation: Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa. JoubertL@arc.agric.za.|Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa. JoubertL@arc.agric.za.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Joubert
authors.affiliation: Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of Technology, P. O. Box 1906, Bellville 7535, South Africa. gelderblomw@cput.ac.za.|Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa. gelderblomw@cput.ac.za.
authors.forename: Wentzel C A
authors.initials: WC
authors.lastname: Gelderblom
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D036903:Aspalathus / Q000737:chemistry*; D047188:Chalcones / Q000008:administration & dosage* / Q000737:chemistry; D019587:Dietary Supplements; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D011916:Rats, Inbred F344; D059467:Transcriptome / Q000187:drug effects
chemical_list: D000975:Antioxidants; D047188:Chalcones; D010936:Plant Extracts; C517016:aspalathin
keywords: biochemical parameters; endogenous antioxidant enzymes; gene expression; herbal tea; serum iron