American Society of Hirudotherapy

Bdellin A

Trypsin-plasmin inhibitor of Kazal-type family — sister to Bdellin B3.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Bdellin A 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 kDaBdellin A5.3 kDa
Molecular weight (kilodaltons) of Bdellin A (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
Trypsin-plasmin inhibitor of Kazal-type family — sister to Bdellin B3.
Evidence level
In vitro
Drug vs leech
Purified natural compound

Clinical translation limit

Bdellin A's in vitro inhibition of trypsin and plasmin does not establish clinical efficacy. No FDA-approved derivative exists. Mechanism is preclinical/biochemical only.

Molecular Profile

Category
Proteinase Inhibitor
Evidence tier
Preclinical
Molecular weight
5,300 Da
Source species
Hirudo medicinalis
Bdellin A molecular structure

Biological Targets

  • → trypsin
  • → plasmin

Key Citations

  1. Fink E et al. (1986), Biol Chem Hoppe-Seyler

External Resources

    Related Proteinase Inhibitor Compounds

    Hirustasin

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

    Eglin C

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

    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.

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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.