Leech saliva

The saliva of the leech contains at least 120 different substances. Many of them are still unresearched, but it has been proven that the combined properties of the secretion from the leech's glands act synergistically and therapeutically. Ever since Hippocrates, it was believed that the most important factor in treatment was the bleeding. In 1903/04, J. B. Haycraft discovered and isolated an anticoagulant agent found in leech saliva and named it hirudin. Today we know that bleeding is of secondary importance in therapy; the most important factor is the leech’s saliva itself, with its active ingredients.

Hirudin: This is the best-known substance in leech saliva. It is made up of 65 amino-acid molecules. It prevents blood from clotting by binding selectively to platelets. When hirudin binds to platelets, a passive compound is formed. When platelets bind with other substances in the blood, however, they form solid polymers, which can block the vessels and bring circulation to a halt. Platelets are extremely important in the process of homeostasis, as they patch up blood vessels when these are damaged, and of course extremely dangerous when larger polymers end up in the bloodstream, as they can cause hypoxia, anoxia or a heart attack.

Calin: Prevents blood from clotting by blocking the binding of collagen via the von Willebrand factor. This means that the wound does not heal for several hours (the duration of the bleeding depends on the type of therapy, the site of application and the individual), which allows prolonged bleeding and the elimination of toxins from the body through the lymphatic fluid.

Destabilase: Causes rapid dissolution of blood clots, which helps to restore blood circulation.

Bdellins: Have anti-inflammatory effects and reduce tissue swelling.

Hyaluronidase: Increases viscosity and has antibiotic effects. Its dispersing factor allows the other substances in the leech's saliva to reach deeper tissues.

Eglins: A group of proteins that act as anti-inflammatories.

Histamine-like substances: Dilate the blood vessels and allow better blood flow at the site of the bite.

Anaesthetic substances: act with a local anaesthetic effect, so that for most people the application is only slightly noticeable or painless.

I. P. Baskova, together with the staff of Moscow State University, discovered that at least three substances in leech saliva have the properties of neurostimulators: destabilase, bdellastasin and bdellin.