Efficacy of Spearmint Tea in Relieving Osteoarthritis of the Knee

• Self-reported ratings of pain and physical function [ Time Frame: Four months ] [ Designated as safety issue: No ]
  Data collection of self-reported ratings of pain and physical function (WOMAC), self-reported ratings of overall physical and mental health (SF-36), and self-reported changes in the use of concomitant pain and inflammation medications (study diary) will occur at baseline (week 0), mid-treatment (week 8), post-treatment (week 16), and follow-up (week 20).
  
  
• Use of concomitant pain/inflammatory medications for the management of osteoarthritis symptoms [ Time Frame: Four months ] [ Designated as safety issue: No ]
  

• Performance-based measures of physical function [ Time Frame: Four months ] [ Designated as safety issue: No ]
  Data for performance-based assessment of physical function (6-minute walk, stair climb task) will be collected at baseline (week 0), mid-treatment (week 8), post-treatment (week 16), and follow-up (week 20).
  
  
• Change in synovial fluid biomarkers of cartilage degradation [ Time Frame: Four months ] [ Designated as safety issue: No ]
  In a sub-set of participants, a synovial fluid sample will be drawn (i.e. arthocentesis) for the analyses of cartilage degradation biomarkers (GAG, COMP, PGE2, NO) at baseline (week 0) and post-treatment (week 16).
  
  

Healthy adults with a clinical diagnosis of osteoarthritis of the knee will be recruited and will undergo a brief phone screening interview, followed by a detailed in-person screening process, to determine study eligibility.

Eligible participants will be matched according to sex, baseline pain according to the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and duration of osteoarthritis. Participants will then be randomly assigned to receive either the investigative high rosmarinic acid spearmint tea or a comparable placebo mint tea.

During the 4-month treatment period, participants will consume two cups (300 mL in the morning and 300 mL in the evening) of either the high rosmarinic acid spearmint tea (approximately 300 mg rosmarinic acid per day) or the commercial spearmint tea (approximately 20 mg of rosmarinic acid per day) daily.

Data collection will occur at baseline (week 0), mid-treatment (week 8), post-treatment (week 16), and follow-up (week 20). Outcome measures include WOMAC and SF-36 scores, physical function (6-minute walk, stair climb task), inflammatory markers (serum C-reactive protein), and self-reported changes in pain medication use. In a sub-set of consenting participants deemed eligible by the study physician, a synovial fluid sample will be drawn from the knee for the analyses of cartilage degradation biomarkers (GAG, COMP, PGE2, NO) at baseline (week 0) and post-treatment (week 16).