Compound Monograph
Mentofuran
Mentofuran is a furan-containing monoterpene found in peppermint oil and a metabolite linked to pennyroyal toxicity.
Classification
Mentofuran is a monoterpene (furanoterpene), part of the terpenoids class. The largest class of plant compounds, built from five-carbon isoprene units — the essential-oil aromatics, resins, bitter principles, saponins, and plant sterols.
Where Does It Come From? (3)
Mentofuran is a naturally occurring monoterpene (furanoterpene), found in Peppermint, Pennyroyal and 1 other source. It is flagged as moderately toxic.
Research & Evidence
Mentofuran is a furan-bearing monoterpene found in peppermint and pennyroyal oils. It is best known as a reactive metabolite of pulegone: in the body pulegone is converted to mentofuran, which is implicated in the hepatotoxicity associated with pennyroyal oil. (The source record’s “furanocoumarin” tag is not accurate — mentofuran is a furanoterpene, not a coumarin.)
Toxicity & Safety
Mentofuran is a bioactivation product associated with liver injury from pennyroyal oil and is best regarded as a compound of toxicological concern rather than a benign flavour constituent. Pennyroyal oil itself can cause severe, sometimes fatal, hepatotoxicity and should not be ingested.