American Society of Hirudotherapy

Leech C1 Inhibitor (LCi)

Complement system modulator targeting C1q activation — immunological homeostasis.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Leech C1 Inhibitor (LCi) 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 kDaLeech C1 Inhibitor (LCi)30 kDa
Molecular weight (kilodaltons) of Leech C1 Inhibitor (LCi) (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
Complement system modulator targeting C1q activation — immunological homeostasis.
Evidence level
In vitro
Drug vs leech
Purified natural compound

Clinical translation limit

Leech C1 inhibitor's reported complement-pathway modulation is preclinical/biochemical only. Not to be confused with the FDA-approved human C1-esterase inhibitor concentrates used in hereditary angioedema — those are unrelated human-plasma products. No leech-derived C1-inhibitor is FDA-approved.

Molecular Profile

Category
Anti-inflammatory
Evidence tier
Preclinical
Molecular weight
30,000 Da
Source species
Hirudo medicinalis
Leech C1 Inhibitor (LCi) molecular structure

Biological Targets

  • complement C1q, classical pathway

Key Citations

  1. Baskova IP, Zavalova LL (2001), Biochemistry (Mosc) · PMID 11563948

External Resources

    Related Anti-inflammatory 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.