American Society of Hirudotherapy

Hirudin-Like Factors (HLFs)

Hirudin-paralog family lacking some structural hirudin features — Müller 2016 phylogenetic characterization across Hirudo and Hirudinaria genera.

Preclinical / mechanisticLast updated: 2026-05-27 · Reviewed by ASH Editorial Board
Molecular weight of Hirudin-Like Factors (HLFs) 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 kDaHirudin-Like Factors (HLFs)7 kDa
Molecular weight (kilodaltons) of Hirudin-Like Factors (HLFs) (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
Hirudin-paralog family lacking some structural hirudin features — Müller 2016 phylogenetic characterization across Hirudo and Hirudinaria genera.
Evidence level
Mechanistic discussion
Drug vs leech
Purified natural compound

Clinical translation limit

HLFs are characterized phylogenetically; their molecular targets are not yet established. No FDA-approved derivative exists; do not extrapolate hirudin clinical activity to HLFs.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
7,000 Da
Source species
Hirudo medicinalis / Hirudo verbana / Hirudinaria manillensis
Discovered
2016 · Müller C et al.
Hirudin-Like Factors (HLFs) molecular structure

Biological Targets

  • → unknown / putative thrombin or other coagulation factors

Key Citations

  1. Müller C et al. (2016), Parasitol Res · PMID 27785600

External Resources

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    Hirudin

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    Antistasin

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    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.