Devil's Claw
An in depth look at a popular anti-inflammatory.
Devil’s Claw (Harpagophytum procumbens) is established as one of the highest selling herbs and is often known as the herbal bute. It has a well deserved reputation as an effective musculo skeletal anti-inflammatory, but it also has wider uses and is helping a broad range of horses over many disciplines.
Devil's Claw grows in Namibia, South Africa and Botswana. The part of the plant that we use medicinally is the secondary tuber. These are grouped around the main roots and serve as water storage to help the plant survive in the desert. With careful harvesting these can be removed without harming the plant, but unfortunately harvesting practices are not always as they might be. The good news is that it is a plant which responds well to cultivation.
The traditional uses for the plant are to treat rheumatism, arthritis, digestive complaints, anorexia, labour pains, fever, kidney and bladder ailments. These uses compare closely to the principal current uses for musculo-skeletal inflammation, degenerative joint disease, and lack of appetite.
Pain and inflammation control through the use of chemically derived anti-inflammatory agents has been one of the greatest contributions of modern medicine. However despite the sophistication of drug design, major complications are still associated with virtually all medications used for pain reduction. On the other hand, plant-derived anti-inflammatories have been successfully used for hundreds or even thousands of years. This is reflected in the growing popularity of herbal medicine principally because of the relatively few side effects. Their evaluation with appropriately designed controlled studies has exploded in recent years, and the findings can be viewed with confidence due to the study designs and quality of the investigators.
Inflammation.
Inflammation is an immune response, which is a dynamic process consisting of complex changes, cellular infiltration, and mediator release that occurs in response to any type of injury or infection. The sequence of events which occur during an inflammatory response can vary, depending on the type or cause of injury, the site of the injury, and the state of the body. The reactions maybe localized or throughout the body. During the inflammation process a cascade of chemical reactions occurs in the affected area. Blood is attracted to the area, blood vessels become more permeable, and white blood cells move from the bloodstream into the injured area. This contributes to the characteristics of inflammation; redness, swelling, heat and pain.
Inflammation is often a major cause of discomfort when your horse is ill or injured, and although we often regard all inflammation as bad it is in fact an important part of the healing process. Inflammation sets the scene for healing. Its role is to quarantine the affected area, remove damaged tissue or pathogens and initiate repair. The healing process should then continue to restoration of function.
If the inflammation phase becomes excessive or prolonged, damage can occur through the resultant tissue changes. In joints, the tissue changes can lead to structural changes which may affect their usefulness through reducing mechanical function, range of movement and the life of a joint. In other tissue hypersensitivity reactions can cause inflammatory diseases which are characterized by activation of the immune system to sustained abnormal levels, which may lead to disease.
The conventional approach to inflammation control has been to use a group of drugs known as Non Steroidal Anti-inflammatories (NSAIDs). These include phenylbutazone (typically called "bute"), flunixin meglumine (Banamine), ketoprofen (Ketofen), meclofenamic acid (Arquel) and acetylsalicylic acid (Aspirin), which can all play a useful role but sometimes come at an unacceptable price in terms of the side effects that may occur.
The well documented side effects that overdose or prolonged NSAID use can cause include gastrointestinal ulcers, kidney damage, oral lesions and internal haemorrhage . These problems are especially pronounced in young, ill, or stressed horses. Recent studies are also showing that the use of NSAIDs prolongs healing time and that if used during exercise can lead to abnormal build up of lactic acid in muscle tissue. This is cause for alarm because this increase in lactic acid can result in further muscle damage.
Devil's Claw and a number of other plant derived anti-inflammatories all work at a variety of levels in a similar way to NSAIDs but generally without the side effects. The full mode of action has yet to be established. However, harpagoside, the principal marker compound found in Devil’s Claw has been shown to interfere with the mechanisms that regulate calcium influx into cells. Calcium influx is required for activation of the enzyme (phospholipase A2) that triggers the cascade of reactions which produce inflammatory eicosanoids. This action is a common property of many anti-inflammatory and analgesic agents and partially explains Devil’s Claw’s anti-inflammatory effect.
The plant has been shown to inhibit the production of leukotrienes and tumour necrosis factor alpha (TNFα). This is significant because TNFα stimulates tissue degeneration and depresses the synthesis of protein. Unlike NSAIDs Devil’s Claw does not alter the activity of cyclooxygenase 1 - an enzyme involved in the production of prostaglandins. This also suggests that it will not have the same irritant effects on the stomach. Although because of its bitterness which stimulates acid production it may aggravate conditions of gastric ulceration.
There have been several studies to demonstrate its effectiveness, but only one comparing herbs to phenylbutazone. Unfortunately it included others herbs as well as Devil's Claw in a mix including Horsetail, Black Currant and Willow, all of which have some anti-inflammatory action. The results of the study showed that the herbal group of horses had significantly less lameness than the phenylbutazone group. There have also been several studies on humans which show that Devil's Claw is as effective as the now withdrawn COX-2 inhibitors and better than placebo.
Where to Use Devil's Claw.
As a safe anti-inflammatory Devil's Claw can be used on a wide range of conditions and in some situations where prolonged use of NSAIDs would be inappropriate. The following list of successful applications shows its versatility.
* Arthritis and rheumatism are common degenerative diseases that affect older horses. Devil’s Claw can definitely help in these situations as it can be used daily for long periods. Similarly it can be used as a chrontroprotective agent for those horses that are in heavy work. It will help to preserve the integrity of the joint and delay the inevitable onset of degenerative joint disease.
* In foals and yearlings epiphysitis can be problematic. Epiphysitis is the inflammation of the growth plates at the bone endings and most often affects the pastern or knee, more commonly in the front legs. This inflammation causes swelling and may result in malformation in the final growth of the leg. Devil’s Claw can be used as part of the treatment and avoids the need to use NSAIDs.
* OCD (osteochondritis dissecans) can result from normal stresses or an injury to a joint resulting in cracks and fissures developing in the cartilage. This causes inflammation in the joint and to the underlying bone and separation of a flap of cartilage. Later osteoarthritis (also called degenerative joint disease) develops in the joint. OCD related inflammation in young warmbloods can be controlled and the swelling resolved.
* Acute conditions that respond well include jarring up from working on hard ground, stone bruises, sprained joints and inflammation associated with cuts and lacerations. Devil's Claw has been used successfully to aid with the healing of quite severe wire cuts, traumatic eye injuries and post operative recovery.
* Acute allergic conditions can also be helped. One such episode involved a severe reaction to a strangles vaccine. The acute anaphylaxis was treated with steroids but the horse became dependent on the steroids until it was treated with Devil's Claw. The steroids were replaced with Devil's Claw which was then withdrawn and the horse made a full recovery.
Complimentary activity.
Devil's Claw is often seen as an alternative to nutriceuticals like chondroitin and glucosamine but it works well in conjunction with these products. Chondroitin and glucosamine both provide the precursors to cartilage repair. There is still some doubt however about how well the large Chondroitin molecules are absorbed in the equine gut. We already understand that cartilage repair produces better results if the level of inflammation is controlled. It seems logical therefore to suggest that these nutriceutical products will work better in the presence of a benign anti-inflammatory like Devil's Claw.
What should I buy ?
Devil's Claw is offered on the market as a dried herb or liquid extract. The dry herb is normally sold as a coarse powder or fine chop product. Under certain circumstances this may be effective but there is good evidence from a range of herbs that an ethanolic extract is more effective.
You may also find liquid Devil's Claw products presented as vinegar extracts, but extracts made using ethyl alcohol achieve better results.
The other important quality issue is the strength of the extract. Most products do not indicate the strength of the extracts, which means that there is no way of knowing what you are buying. It's a bit like buying a horse without knowing whether to expect a Clydesdale or a Shetland pony to come off the truck.
This is a serious issue for consumers and all manufacturers should be encouraged to declare the strength of their products.
One of the criticisms that mainstream medicine makes of natural therapies is that there is no measure of quality, consistency or reliability between manufacturers. Many make their extracts to a strength of 1:5, others to a strength of 1:2. The latter being two and half times as strong as the former. Regrettably some companies don't even know the strength of their own products!
When you buy Devil's Claw make sure you know how strong they are. If the shop can't tell you ring the manufacturer. If they can't tell you, don't buy it.
|
