title: Effect of a dietary supplement containing glucosamine hydrochloride, chondroitin sulfate and quercetin glycosides on symptomatic knee osteoarthritis: a randomized, double-blind, placebo-controlled study.
abstract: BACKGROUND
  Oral glucosamine and chondroitin sulfate, alone and in combination, have been used worldwide for the treatment of osteoarthritis (OA), but their efficacy is controversial. This clinical study was aimed at investigating the potential of a dietary supplement containing glucosamine and chondroitin sulfate in combination with derivatives of quercetin, a naturally occurring flavonoid, (GCQ supplement) for knee OA care.
  
  
  RESULTS
  A randomized, double-blind, placebo-controlled study was conducted in 40 Japanese subjects with symptomatic knee OA. Subjects were randomly assigned to GCQ supplement (1200 mg glucosamine hydrochloride, 60 mg chondroitin sulfate and 45 mg quercetin glycosides per day) or placebo and the treatment and follow-up were continued for 16 weeks. The results of symptomatic efficacy assessment based on Japanese Orthopaedic Association criteria showed that scores for two of the four symptom/function subscales, as well as the aggregate scores, were significantly improved at week 16 or earlier in the GCQ group compared to the placebo group. Moreover, analyses of cartilage metabolism biomarkers showed a trend of improvement in type II collagen synthesis/degradation balance in the GCQ group during follow-up.
  
  
  CONCLUSIONS
  GCQ supplement was thought to be more effective than placebo in decreasing the intensity of knee OA-associated clinical symptoms.
authors.affiliation: Institute for Health Care Science, Suntory Wellness Ltd, Mishima-gun, Osaka, Japan. Noriyuki_Kanzaki@suntory.co.jp
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kanzaki
authors.forename: Kayo
authors.initials: K
authors.lastname: Saito
authors.forename: Akifumi
authors.initials: A
authors.lastname: Maeda
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kiso
authors.forename: Keita
authors.initials: K
authors.lastname: Watanabe
authors.forename: Akihito
authors.initials: A
authors.lastname: Tomonaga
authors.forename: Isao
authors.initials: I
authors.lastname: Nagaoka
authors.forename: Hideyo
authors.initials: H
authors.lastname: Yamaguchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use; D018771:Arthralgia / Q000209:etiology / Q000517:prevention & control; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002809:Chondroitin Sulfates / Q000009:adverse effects / Q000627:therapeutic use*; D024043:Collagen Type II / Q000097:blood / Q000652:urine; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D005944:Glucosamine / Q000009:adverse effects / Q000627:therapeutic use*; D006027:Glycosides / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood / Q000178:diet therapy* / Q000503:physiopathology / Q000652:urine; D010446:Peptide Fragments / Q000097:blood / Q000652:urine; D011794:Quercetin / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use*; D012720:Severity of Illness Index
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D024043:Collagen Type II; D006027:Glycosides; D010446:Peptide Fragments; D002809:Chondroitin Sulfates; D011794:Quercetin; D005944:Glucosamine