American Society of Hirudotherapy

Sylvestin

43-amino-acid contact-kinin pathway inhibitor from forest leech Haemadipsa sylvestris — plasma kallikrein + FXIIa dual blocker; preclinical stroke neuroprotection without bleeding tendency.

Preclinical / mechanisticLast updated: 2026-05-27 · Reviewed by ASH Editorial Board
Molecular weight of Sylvestin 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 kDaSylvestin4.8 kDa
Molecular weight (kilodaltons) of Sylvestin (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
43-amino-acid contact-kinin pathway inhibitor from forest leech Haemadipsa sylvestris — plasma kallikrein + FXIIa dual blocker; preclinical stroke neuroprotection without bleeding tendency.
Evidence level
Preclinical (animal)
Drug vs leech
Recombinant (genetically expressed)
Safety domains
Bleeding

Clinical translation limit

Sylvestin's neuroprotection in rodent ischemic stroke models does NOT establish clinical efficacy in humans. No FDA-approved sylvestin derivative exists. The reported 'no bleeding tendency' result is from animal models only; human bleeding-risk profiles cannot be inferred.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
4,790 Da
Source species
Haemadipsa sylvestris
Discovered
2022 · Zhang Z et al.
Sylvestin molecular structure

Biological Targets

  • plasma kallikrein
  • activated Factor XII (FXIIa)

Key Citations

  1. Zhang Z et al. (2022), Cell Mol Life Sci · PMID 35416530

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.