Current nutraceuticals in the management of osteoarthritis: a review.

Osteoarthritis (OA) is a progressive degenerative joint disease that has a major impact on joint function and quality of life. Nutraceuticals and dietary supplements derived from herbs have long been used in traditional medicine and there is considerable evidence that nutraceuticals may play an important role in inflammation and joint destruction in OA. We review the biological effects of some medicinal fruits and herbs - pomegranate, green tea, cat's claw, devil's claw, ginger, Indian olibaum, turmeric and ananas - in an attempt to understand the pivotal molecular targets involved in inflammation and the joint destruction process and to summarize their toxicities and efficacy for OA management. So far there is insufficient reliable evidence on the effectiveness of ginger, turmeric and ananas. Pomegranate and green tea only have preclinical evidence of efficacy due to the lack of clinical data. In vivo and clinical studies are required to understand their targets and efficacy in OA. Limited in vitro and in vivo evidence is available for cat's claw and Indian olibaum. More extensive studies are required before long-term controlled trials of whole cat's claw and Indian olibaum extracts, or isolated active compounds, are carried out in patients with OA to determine their long-term efficacy and safety. Devil's claw has not been rigorously tested to determine its antiarthritic potential in in vitro and in vivo models. There is strong clinical evidence of the effectiveness of devil's claw in pain reduction. However, high-quality clinical trials are needed to determine its effectiveness. No serious side effects have been reported for any fruits and herbs. Overall, these studies identify and support the use of nutraceuticals to provide symptomatic relief to patients with OA and to be used as adjunct therapy for OA management. More high-quality trials are needed to provide definitive answers to questions related to their efficacy and safety for OA prevention and/or treatment.