Lindow man, Tollund man and other peat-bog bodies: the preservative and antimicrobial action of sphagnan, a reactive glycuronoglycan with tanning and sequestering properties
Key Findings
- Identifies sphagnan as the key antimicrobial polysaccharide in sphagnum moss
- Explains the preservative properties of peat bogs through sphagnan's tanning and sequestering activity
- Links sphagnum's wound dressing history to specific biochemical mechanisms
With 242 citations, one of the most-referenced papers in sphagnum science. Published in Carbohydrate Polymers, Painter’s review makes an elegant argument: the extraordinary preservation of bog bodies (Lindow Man, Tollund Man, and dozens of others across Northern Europe) is direct physical evidence for sphagnum moss’s antimicrobial power — the same preserved bodies that demonstrate this property also happen to be thousands of years old, confirming the durability of the effect.
The Compound: Sphagnan
The active agent responsible for both preservation and antimicrobial activity is sphagnan — a reactive glycuronoglycan (a type of polysaccharide with carboxyl-bearing sugar units) unique to sphagnum moss. Sphagnan acts through two mechanisms:
Tanning — sphagnan reacts with and cross-links proteins, altering their structure and making them resistant to microbial degradation. This is the same chemistry that tanning uses to preserve animal hides into leather. Applied to tissue, it prevents the enzymatic breakdown that would normally produce decomposition.
Metal sequestration — sphagnan binds divalent cations (Ca²⁺, Mg²⁺, Fe²⁺, etc.) with high affinity, sequestering them from the bog environment. Since many bacterial enzymes require metal cofactors to function, removing those metals effectively disables microbial metabolism. The bog becomes hostile to microbial life at the chemical level.
Why It Matters for Peat
Sphagnan is present in sphagnum-derived peat, particularly in higher-moor (ombrotrophic, sphagnum-dominated) peat. It is distinct from the humic substances that dominate the peat therapy literature, representing an additional antimicrobial mechanism. The historical wound dressing use of sphagnum (documented in WWI and before) is now explained by sphagnan’s tanning and sequestering activity — not empirical folklore but biochemistry that preceded formal identification of the compound.