Study on a Novel Analgesic Peptide from the Digestive Juice of Land Leeches

Chenxi Zeng

Haemadipsa, also known as land leeches, is a genus of annelids feeding on blood. Although the biology and reproductive ecology of the species have been studied, no previous research has shown the analgesic active ingredients in their bodies. In this work, the digestive tract secretions of Haemadipsa guangchuanensis have been investigated using chromatography, RP-HPLC (reversed-phase high performance liquid chromatography), and an in vivo study on mice. The result of the study proved the existence of an analgesic peptide, HGSN1, in the body of the leech. Furthermore, the result suggests that the active peptide HGSN1 is a key ingredient secreted by Haemadipsa guangchuanensis to avoid being noticed while sucking blood. As HGSN1 can potentially be adapted as a precursor compound to develop novel analgesic drugs, it would be of great importance to carry out further research on the structural analysis of the peptide.