American Society of Hirudotherapy

Haemadin

Picomolar-affinity thrombin inhibitor from Indian buffalo leech — distinct mechanism from hirudin.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Haemadin compared with other characterized leech-derived compoundsHementerin80 kDaHementin80 kDaHementin-Like Protein (HLP-1)80 kDaLeech Collagenase70 kDaHaemadipsa yanyuanensis Progr…70 kDaLeech Apyrase67 kDaCalin65 kDaHyaluronidase60 kDaAntithrombin III binding prot…58 kDaCollagenolytic Fibrinolysin55 kDaLeech Thrombospondin-Like Pro…50 kDaHaemadin5.2 kDa
Molecular weight (kilodaltons) of Haemadin (highlighted) alongside other characterized leech salivary compounds. Smaller proteins/peptides generally diffuse and act faster.

Mechanistic Evidence Box

Preclinical / mechanistic
Page type
Compound profile
Evidence type
Picomolar-affinity thrombin inhibitor from Indian buffalo leech — distinct mechanism from hirudin.
Evidence level
In vitro
Drug vs leech
Purified natural compound
Safety domains
Bleeding

Clinical translation limit

Haemadin's in vitro thrombin inhibition does not establish clinical efficacy. No FDA-approved derivative exists. Mechanism is preclinical/biochemical only.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
5,183 Da
Source species
Haemadipsa sylvestris
Discovered
1991 · Strube KH et al.
PDB structures
1E0F
Haemadin molecular structure

Biological Targets

  • → thrombin (exosite I, non-exosite II)

Key Citations

  1. Strube KH et al. (1993), J Biol Chem · PMID 8473305

External Resources

Related Anticoagulant Compounds

Hirudin

The most potent natural thrombin inhibitor — and the molecular template for three FDA-approved direct thrombin inhibitor drugs.

Antistasin

Factor Xa inhibitor — prototype molecule that inspired the entire DOAC drug class (rivaroxaban, apixaban).

Ghilanten

Factor Xa inhibitor with anti-metastatic activity in animal cancer models — translational dual-use compound.

Lefaxin

Factor Xa inhibitor with anti-inflammatory properties.

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This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.