RK22
Novel antimicrobial peptide from Hirudinaria manillensis salivary transcriptome — MIC 6.25 µg/mL against MRSA, no thrombogenic effect, in vivo efficacy in mice.
Mechanistic Evidence Box
Preclinical / mechanistic- Page type
- Compound profile
- Evidence type
- Novel antimicrobial peptide from Hirudinaria manillensis salivary transcriptome — MIC 6.25 µg/mL against MRSA, no thrombogenic effect, in vivo efficacy in mice.
- Evidence level
- Preclinical (animal)
- Drug vs leech
- Purified natural compound
- Safety domains
- Antibiotic stewardship
Clinical translation limit
RK22's in vitro and murine antibacterial activity does NOT establish clinical efficacy in humans. No FDA-approved derivative exists; H. manillensis is not the FDA-cleared K040187 medicinal leech species.
Molecular Profile
- Category
- Antimicrobial
- Evidence tier
- Preclinical
- Molecular weight
- 2,700 Da
- Source species
- Hirudinaria manillensis
- Discovered
- 2023 · Lu X et al.
Biological Targets
- → Methicillin-resistant Staphylococcus aureus (MRSA)
- → Staphylococcus biofilm
Key Citations
- Lu X et al. (2023), Int J Mol Sci · PMID 37686259
External Resources
Related Antimicrobial Compounds
Theromacin
Antimicrobial peptide active against Gram-negative bacteria — innate immunity of leech.
Theromyzin
Antimicrobial peptide; structural analogue of mammalian defensin family.
Macrostomin
Antimicrobial peptide active against Gram-positive bacteria — amphipathic alpha-helix.
Hirunipins
Newly-characterized antimicrobial peptide family (Kumar 2025) — candidate next-generation antibiotics against AMR pathogens.