By Pat Anson, Editor

A creepy looking parasitic mushroom that lives on caterpillars could help British researchers develop a new class of painkillers to treat osteoarthritis and other chronic pain conditions.

Scientists at the University of Nottingham are exploring the painkilling potential of cordycepin, a compound found in cordyceps mushrooms, which have been used in traditional Chinese medicine for thousands of years.

The mushroom acts as a parasite in the larvae of ghost moths – growing inside the caterpillar until it eventually kills it. The stalk-like mushroom then grows out of the caterpillar’s mummified body.

Food pellets containing the compound were given to rats and mice to see if cordycepin could relieve pain from a joint injury. The results, according to researchers, were startling.

"When we first started investigating this compound it was frankly a bit of a long-shot and there was much skepticism from the scientific community," said Dr. Cornelia de Moor. "But we were stunned by the response from the pilot study, which showed that it was as effective as conventional painkillers in rats.

"This study is the first step in a potential drug development for a new class of drugs for osteoarthritis, although there are a number of hurdles we have to go through - necessarily so - before it gets nearer patients. To the best of our knowledge, cordycepin has never been tested as a lead compound for osteoarthritis pain."

Native Tibetan healers have used cordyceps mushrooms as a tonic to treat a wide variety of conditions. They claim it improves energy, appetite, stamina, libido, endurance, and sleeping.

Researchers believe cordycepin blocks the inflammatory process that cause pain in osteoarthritis, but does so in a way that is completely different than painkillers like corticosteroids and non-steroidal-anti-inflammatory drugs (NSAIDs) such as ibuprofen.  Still unclear is whether cordycepin acts on the knee joint or on the nerves that send pain signals from the knee to the spinal cord.

Until clinical trials can be held to test the safety and effectiveness of cordycepin – which could take years – de Moor warns against people experimenting with herbal products containing the cordyceps mushroom.

"The lack of quality control means that cordyceps preparations for sale in Europe rarely contain much cordycepin, and may contain other harmful compounds," said de Moor, who is also investigating cordycepin as a possible treatment for cancer.

"Dr de Moor's research is certainly novel, and we believe may hold promise as a future source of pain relief for people with osteoarthritis. There is currently a massive gap in available, effective, side-effect-free painkillers for the millions of people with arthritis who have to live with their pain every day, so new approaches are very much-needed,"  said Dr. Stephen Simpson, director of research at Arthritis Research UK, which is helping to fund de Moor’s research.

Osteoarthritis is a progressive joint disorder caused by painful inflammation of soft tissue, which leads to thinning of cartilage and joint damage in the knees, hips, fingers and spine. The World Health Organization estimates that about 10% of men and 18% of women over age 60 have osteoarthritis.