Shui Zhi (Hirudo nipponica) (Hirudo nipponica)

Shui Zhi (Hirudo nipponica) is a medicinal leech with a protein-dominant composition. Crude protein content is approximately 60-70% of dry weight, comprising bioactive peptides and enzymes as primary constituents. The most characterized bioactive compound is Hirudin, a potent thrombin inhibitor present at approximately 0.1-1.0 mg per gram of dried material, responsible for anticoagulant activity. Destabilase (a glycosidase-amidase enzyme) is present and contributes to fibrinolytic activity. Hyaluronidase is present at measurable levels, facilitating tissue penetration of therapeutic compounds. Lipid content is low, approximately 5-10% of dry weight, with phospholipids as primary lipid fraction. Carbohydrate content is minimal, approximately 3-5% of dry weight, predominantly as glycoproteins. Mineral content includes iron (approximately 2-5 mg/100g dry weight), zinc (approximately 1-3 mg/100g), and calcium (approximately 50-100 mg/100g). Histamine and serotonin are present as biogenic amines at trace concentrations (0.01-0.05 mg/g). Calin, a platelet aggregation inhibitor, and bdellins (serine protease inhibitors) are present at microgram-per-gram concentrations. Bioavailability note: Hirudin is degraded by gastric proteases when orally administered, so traditional preparations often use dried powder or topical forms to preserve activity; bioavailability of intact hirudin via oral route is estimated below 5% without protective formulation.