Lipid of the Month

Each month we highlight a lipid of scientific interest. The LIPID MAPS® Lipid of the Month Archive lists lipids highlighted from 2015 - present.

May 2021

Lipid of the month 2-chloropalmitaldehyde

May’s Lipid of the Month is generated by one of the immune system’s many mechanisms used to protect the body from pathogens. 2-chlorohexadecanal is formed when the vinyl ether bond of plasmalogen lipids containing a 1Z-hexadecenyl chain (for example 1-(1Z-hexadecenyl)-2-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine) is attacked by endogenous hypochlorous acid (HOCl)1. The resulting 2-chloroaldehyde can subsequently oxidise to form a 2-chloro fatty acid.

HOCl is produced by neutrophils from hydrogen peroxide and chloride ions with the aid of the enzyme myeloperoxidase, located in the lysosome. This relatively strong oxidising agent will react with many compounds, essentially destroying anything within the lysosome. HOCl also dissociates to hypochlorite, the active constituent of bleach, but it should not be necessary to stress that attempting to augment the immune system by adding bleach is a very bad idea!!

2-chlorohexadecanal is not simply a lipid breakdown product but acts as a signalling molecule of infection itself. Its presence indicates a site of infection or inflammation and attracts other neutrophils to the site2. It can also induce expression of cyclooxygenase-23, the enzyme which forms prostaglandin H2, another part of the inflammation pathway.


  • Reactive chlorinating species produced by myeloperoxidase target the vinyl ether bond of plasmalogens: identification of 2-chlorohexadecanal
    J. Biol. Chem
    DOI 10.1074/jbc.M101447200
  • Reactive Chlorinating Species Produced during Neutrophil Activation Target Tissue Plasmalogens
    J. Biol. Chem
    DOI 10.1074/jbc.M109489200
  • 2-Chlorohexadecanal and 2-chlorohexadecanoic acid induce COX-2 expression in human coronary artery endothelial cells
    DOI 10.1007/s11745-008-3189-y

Lipid of the Month Archive