American Society of Hirudotherapy

Bdellin-HM-2

Non-classical Kazal-type protease inhibitor from Hirudinaria manillensis — prolongs aPTT without inhibiting trypsin, thrombin, FXa, FXIIa, or kallikrein (Cheng 2019).

Preclinical / mechanisticLast updated: 2026-05-27 · Reviewed by ASH Editorial Board
Molecular weight of Bdellin-HM-2 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-HM-214 kDa
Molecular weight (kilodaltons) of Bdellin-HM-2 (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
Non-classical Kazal-type protease inhibitor from Hirudinaria manillensis — prolongs aPTT without inhibiting trypsin, thrombin, FXa, FXIIa, or kallikrein (Cheng 2019).
Evidence level
In vitro
Drug vs leech
Purified natural compound
Safety domains
Bleeding

Clinical translation limit

Bdellin-HM-2's in vitro aPTT-prolonging activity does NOT establish clinical anticoagulant efficacy. No FDA-approved derivative exists; H. manillensis is not the FDA-cleared K040187 medicinal leech species. The molecular target remains uncharacterized despite the demonstrated phenotypic anticoagulant effect.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
14,000 Da
Source species
Hirudinaria manillensis
Discovered
2019 · Cheng RM et al.
Bdellin-HM-2 molecular structure

Biological Targets

  • aPTT-prolonging anticoagulant mechanism (non-classical, target unidentified)

Key Citations

  1. Cheng RM et al. (2019), Zool Res · PMID 31011131

External Resources

    Related Anticoagulant Compounds

    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.