title: Bioassay-guided isolation of anti-inflammatory and antinociceptive principles from a folk remedy, Rhododendron ponticum L. leaves.
abstract: BACKGROUND
  Rhododendron ponticum L. (Ericaceae) is used for the treatment of inflammatory diseases and to alleviate rheumatic pain and against toothache in Turkish traditional medicine.
  
  
  OBJECTIVE
  To evaluate the anti-inflammatory and antinociceptive effects of Rhododendron ponticum leaves using in vivo models, and isolation and chemical characterization of the biologically active constituents through bioassay-guided fractionation procedures.
  
  
  METHODS
  Carrageenan-induced hind paw edema model was used for anti-inflammatory activity and p-benzoquinone induced abdominal contractions model for the antinociceptive activity assessment.
  
  
  RESULTS
  The ethylacetate fraction displayed marked anti-inflammatory (28.4-40.7% inhibition) and antinociceptive (50.7% inhibition) effects as compared to reference compounds. Through bioassay-guided fractionation and isolation procedures flavonol glycosides [a mixture of hyperoside and isoquercitrin (1) and quercitrin (2)] along with one flavanone glycoside [6-C-glycosylnaringenin (3)] were isolated as the active ingredients of ethylacetate extract against carrageenan-induced edema and p-benzoquinone-induced writhes and their structures were elucidated by spectral techniques. 1 and 2 also showed a significant anti-inflammatory activity against 12-O-tetradecanoyl-13-acetate (TPA)- induced mouse ear edema model.
  
  
  CONCLUSIONS
  Results of the present study supported the utilization of the plant in Turkish folk medicine and revealed that flavones are the major anti-inflammatory and antinociceptive principles of the leaves.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, Etiler 06330, Ankara, Turkey.
authors.forename: Nurgun
authors.initials: N
authors.lastname: Erdemoglu
authors.forename: Esra Küpeli
authors.initials: EK
authors.lastname: Akkol
authors.forename: Erdem
authors.initials: E
authors.lastname: Yesilada
authors.forename: Ihsan
authors.initials: I
authors.lastname: Caliş
mesh_terms: D000700:Analgesics / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001681:Biological Assay; D004195:Disease Models, Animal; D004487:Edema / Q000188:drug therapy; D047309:Flavones / Q000302:isolation & purification / Q000494:pharmacology; D007249:Inflammation / Q000188:drug therapy; D008297:Male; D008519:Medicine, Traditional; D051379:Mice; D010146:Pain / Q000188:drug therapy; D010147:Pain Measurement; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D029793:Rhododendron / Q000737:chemistry*; D014421:Turkey
chemical_list: D000700:Analgesics; D000893:Anti-Inflammatory Agents; D047309:Flavones; D010936:Plant Extracts