Oral intake of purple passion fruit peel extract reduces pain and stiffness and improves physical function in adult patients with knee osteoarthritis

Knee osteoarthritis (OA) is a common degenerative joint disorder and a major cause of pain and disability. The hypothesis tested in this study was that the passion fruit peel extract (PFP), a flavonoid-rich dietary supplement, would reduce symptoms due to knee OA. Thirty-three OA patients were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design. Patients received either placebo or PFP pills (150 mg, daily) in a double-blinded fashion for 2 months. The OA clinical symptoms were evaluated monthly with Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index. In the PFP group, there was a significant improvement in total WOMAC score and WOMAC subscale score of physical function after 30 days and pain after 60 days. At 60 days, reductions of 18.6%, 18%, 19.6%, and 19.2% in pain, stiffness, physical function, and composite WOMAC score, respectively, were self-reported in the PFP group. Whereas, in the placebo group, the self-reported WOMAC scores increased in every category. The results of this study show that PFP substantially alleviated osteoarthritis symptoms. This beneficial effect of PFP may be due to its antioxidant and antiinflammatory properties. (C) 2010 Elsevier Inc. All rights reserved.