American Society of Hirudotherapy

Eglin C

Potent inhibitor of human leukocyte elastase and cathepsin G — anti-inflammatory protein widely used as research tool.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Eglin C 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 kDaEglin C8.1 kDa
Molecular weight (kilodaltons) of Eglin C (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
Potent inhibitor of human leukocyte elastase and cathepsin G — anti-inflammatory protein widely used as research tool.
Evidence level
In vitro
Drug vs leech
Purified natural compound

Clinical translation limit

Eglin C is a research-grade biochemical tool; its in vitro inhibition of human leukocyte elastase does not establish clinical anti-inflammatory efficacy. No FDA-approved derivative exists.

Molecular Profile

Category
Proteinase Inhibitor
Evidence tier
Preclinical
Molecular weight
8,100 Da
Source species
Hirudo medicinalis
Discovered
1980 · Seemüller et al.
PDB structures
1ACB1EAI
Eglin C molecular structure

Biological Targets

  • → leukocyte elastase
  • → cathepsin G
  • → chymotrypsin

Key Citations

  1. Seemüller U et al. (1980), FEBS Lett
  2. Heinz et al. (1992), Biochemistry

External Resources

Related Proteinase Inhibitor Compounds

Hirustasin

Serine proteinase inhibitor targeting tissue kallikrein — anti-inflammatory pathway.

Bdellin B3

Kazal-type proteinase inhibitor targeting trypsin and plasmin — modulates inflammatory cascade.

LDTI (Leech-Derived Tryptase Inhibitor)

Selective inhibitor of human mast cell tryptase — anti-inflammatory pathway.

LCI (Leech Carboxypeptidase Inhibitor)

Inhibitor of TAFI (thrombin-activatable fibrinolysis inhibitor) — synergizes with hirudin's anticoagulant action.

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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.