A natural classic with a big future

At Merck, developing the drugs of the future involves not only a search for new active ingredients; it also requires continuous assessment of tried and tested products. Recent clinical tests of Kytta-Salbe® led to impressive results. Although it had been known for years that the pain-relief ointment containing natural ingredients from comfrey root extract is just as effective as synthetic drugs for treating muscle and joint pain, this fact has now been proven by the new clinical study.

In a double-blind study involving 143 patients suffering from ankle joint distortions, Kytta-Salbe® was shown to be at least as effective as a gel containing the synthetically produced active ingredient Diclofenac. The comfrey root ointment was even superior in several respects, including the main target criterion. The impressive results of the comparative study were presented at a press conference held at Harvard University in Cambridge, Massachusetts. “We are continuing with the clinical tests, which we expect will provide us with much more good news in the future,” says Julia Wehner, Product Manager for Kytta products.

Merck has had the pain-relief ointment with comfrey root extract in its product lineup for many years. The basic recipe was developed in the Black Forest back in 1931. But even in ancient times physicians knew of the analgesic and healing effect of the roots of comfrey (Symphytum officinale L.). Among them was the Greek medical expert and pharmacist Dioscurides, who practiced in Rome in the first century AD. The plant’s effects, which Dioscurides described in his five-volume work De Materia Medica, is also reflected in its German name, Beinwell. The word consists of the elements “bein” (“bone”) and “well” (from Wallen, meaning “growing together”).

Comfrey found its way into folk medicine — and the recipe books of illustrious figures in medical history, including Paracelsus and Hildegard of Bingen. And the plant’s use wasn’t confined to Europe; Christian missionaries taught North American Indians how to use comfrey to treat muscle and joint pains, sprains, rheumatism, and gout, thus helping to make comfrey’s use as a medicinal plant widespread on the continent. Merck Selbstmedikation GmbH once highlighted this early case of medical information exchange between cultures by using the slogan “An Indian knows no pain”.

Even people who are not aware of the historic roots of comfrey use will quickly be convinced of the ointment’s effectiveness by the new studies. In the past several years, research with this ointment has focused on knee joint arthritis and ankle joint distortions. Merck uses the same precision in producing the extract as it does in clinically studying the ointment. That’s because the natural ingredient has to meet the same quality standards as synthetic ones. Merck partner companies let the comfrey plants grow for at least three years before they are harvested and the roots are processed into the ointment. At this age, the plants have a sufficient concentration of active ingredients in their roots for them to be harvested in fall or winter, depending on the region of cultivation. A special process is used to produce a liquid extract from the plant, which is then incorporated into the ointment. When applied to the skin on the painful area, the active ingredient can get to work quickly and effectively.