The skin is the human body’s first line of de- fense and its uppermost protective barrier. As an unbroken layer, it prevents bacteria and other pathogens from penetrating through to deeper layers and doing damage there. As soon as the skin is damaged, the body initiates a pro- gram to repair it with perfectly coordinated steps. Sometimes this process takes a long time, or the wound doesn’t heal at all and becomes chronic. Natural substances extracted from the birch tree have served for centuries as a traditional means of getting wounds to close more quickly. As early as the Middle Ages, the scholar and ab- bess Hildegard of Bingen recommended using birch bark and other parts of the tree to treat wounds, pimples, and other aches and pains. Prof. Dr. Irmgard Merfort from the Institute of Pharmaceutical Sciences of the University of Freiburg and her research team put these meth- ods to the test to determine whether they are ac- tually useful. “Our aim was to find the scientific basis for this centuries-old tradition,” says Mer- fort. Together with several cooperation partners, the team investigated how birch bark extract and the substances it contains take effect on the mo- lecular level during the various phases of wound healing. In a clinical study on patients who had sus- tained second-degree burns, a cream with birch bark extract sped up the healing process. In an- other study, doctors treated two damaged patch- es of skin directly adjacent to one another differently, and here as well the skin treated with natural substances from the birch showed their rapid therapeutic effects. The extract the team used is obtained from the outer, white layer of the tree, a waste product of the timber industry. Its effect is based among other things on the chemical substances betulin, lupeol, betulinic acid, erythrodiol, and oleanolic acid. “The main component is betulin at 87 percent. The other substances are present in lower concentrations. Only around three percent of the extract con- sists of substances we are not familiar with,” explains Merfort. In all of their studies, the Medicines that grow in the forest: The healing properties of the birch have been appreciated for centuries. Photo: jordano/Fotolia From bark to powder: Birch bark extract is produced from the external, white layer of the trunk. Photos: Armin Scheffler “An inflammation is nothing other than a defensive reaction of the body and is an integral part of the healing process” 25