title: Amelioration of lipopolysaccharide-induced liver injury by aqueous rooibos (Aspalathus linearis) extract via inhibition of pro-inflammatory cytokines and oxidative stress.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Overall, our data showed that aqueous rooibos extract attenuated LPS-induced liver injury possibly by modulating oxidative stress and suppressing pro-inflammatory cytokines formation.
authors.forename: Olawale Razaq
authors.initials: OR
authors.lastname: Ajuwon
authors.forename: Oluwafemi Omoniyi
authors.initials: OO
authors.lastname: Oguntibeju
authors.affiliation: Oxidative Stress Research Centre, Institute of Biomedical and Microbial Biotechnology, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, PO Box 1906 Bellville 7535, South Africa. marnewickj@cput.ac.za.
authors.forename: Jeanine Lucasta
authors.initials: JL
authors.lastname: Marnewick
mesh_terms: D000818:Animals; D036903:Aspalathus / Q000737:chemistry*; D056486:Chemical and Drug Induced Liver Injury / Q000188:drug therapy*; D016207:Cytokines / Q000097:blood; D008070:Lipopolysaccharides / Q000633:toxicity; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D010936:Plant Extracts