Wikipedia
Velleral
Velleral (2,2,8-trimethyl-3,3a,8,8a-tetrahydro-1H-azulene-5,6-dicarbaldehyde) is a sesquiterpene dialdehyde found in certain mushrooms, like Lactarius torminosus and Lactarius vellereus, after which it was named. The compound is thought to be part of a chemical defense system that protects the mushrooms against predation. First isolated in 1969, and characterized structurally in 1973, velleral has antimicrobial activity. Several syntheses have been devised.