The phytonutrient called sulphoraphane, the compound has already been shown to fight cancer cell growth. But new experiments on human cells show that a diet rich in sulphoraphane might also be good for arthritic joints, or for sportspeople putting their joints under a lot of pressure.

 A team from Johns Hopkins university added the broccoli compound to a dish containing chondrocyte cells from human joints. After 24 hours, the cells were subjected to a stress test designed to mimic aspects of strenuous exercise on a joint.

 Heavy exertion can cause the joints to increase the levels of COX-2 enzyme in joints, which triggers inflammation and pain, and suppresses the activity of phase 2 enzymes. This ultimately kills chondrocytic cells, and when chondrocytes stop functioning properly, arthritis can develop.

  But sulphoraphane has previously been found to boost the activity of helpful phase 2 enzymes, and the laboratory test confirmed this effect.

  "The beneficial phase 2 enzymes somehow seemed to prevent the activation of the inflammatory COX-2 enzyme," said graduate student Zachary Healy, lead author of the paper published in the 27 September edition of Proceedings of the National Academy of Sciences (vol 102, no 39, 14010-14015).

   "The phase 2 enzymes inhibited the inflammation and the apoptosis - the cellular suicide we'd observed."

 Healy suggests that supplements of the natural compounds could be used prior to sport. Further, prescription drugs like Vioxx keep COX-2 enzyme at bay by temporarily blocking its ability to send the biochemical signals that set off pain and inflammation. When the medication is stopped, the stockpiled COX-2 enzyme can resume its damaging ways.But the phase 2 enzyme inducers seemed to stop the increasing activity of COX-2 enzyme.

 "This has the potential for stopping pain and inflammation before they start," said Healy.

 The findings prove timely as the withdrawal of Cox-2 inhibitor drugs last year encourages consumers to look at natural substances to relieve joint pain.

   At the same time, incidence of osteoarthritis is rapidly rising around the world due both to ageing populations and increasing levels of obesity.

 "The results need to be tested in an animal model and then because these compounds are readily available in foods, we could probably move quickly to testing them in a clinical trial,".