title: Kynurenic acid content in anti-rheumatic herbs.
abstract: BACKGROUND
  The use of herbal medicines is common among people living in rural areas and increasingly popular in urbanized countries. Kynurenic acid (KYNA) is a metabolite of kynurenine possessing anti-inflammatory, anti-oxidative and pain reliving properties. Previous data indicated that the content of KYNA in the synovial fluid of patients with rheumatoid arthritis is lower than in patients with osteoarthritis. Rheumatoid arthritis is a chronic, systemic inflammatory disorder affecting about 1% of the world's population.
  
  
  OBJECTIVE
  The aim of the presented study was to investigate the content of KYNA in 11 herbal preparations used in rheumatic diseases.
  
  
  METHODS
  The following herbs were studied: bean pericarp, birch leaf, dandelion root, elder flower, horsetail herb, nettle leaf, peppermint leaf and willow bark. An anti-rheumatic mixture of the herbs Reumatefix and Reumaflos tea were also investigated. The herbs were prepared according to producers' directions. In addition, the herbal supplement Devil's Claw containing root of Harpagophytum was used. KYNA content was measured using the high-performance liquid chromatography method, and KYNA was detected fluorometrically.
  
  
  RESULTS
  KYNA was found in all studied herbal preparations. The highest content of KYNA was found in peppermint, nettle, birch leaf and the horsetail herb. The lowest content of KYNA was found in willow bark, dandelion root and in the extract from the root of Harpagophytum.
  
  
  CONCLUSIONS
  These findings indicate that the use of herbal preparations containing a high level of KYNA can be considered as a supplementary measure in rheumatoid arthritis therapy, as well as in rheumatic diseases prevention.
authors.affiliation: Department of Toxicology, Institute of Rural Health, Lublin, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zgrajka
authors.affiliation: Department of Experimental and Clinical Pharmacology, Medical University, Lublin, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Turska
authors.affiliation: Department of Pharmacology, Medical University, Lublin, Poland.
authors.forename: Grażyna
authors.initials: G
authors.lastname: Rajtar
authors.affiliation: Department of Rheumatology and Connective Tissue Diseases, Medical University, Lublin, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Majdan
authors.affiliation: Department of Rheumatology and Connective Tissue Diseases, Medical University, Lublin, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Parada-Turska
mesh_terms: D006801:Humans; D007736:Kynurenic Acid / Q000737:chemistry*; D028321:Plant Preparations / Q000032:analysis* / Q000627:therapeutic use; D010946:Plants, Medicinal / Q000737:chemistry*; D012216:Rheumatic Diseases / Q000188:drug therapy*
chemical_list: D028321:Plant Preparations; D007736:Kynurenic Acid