Structures and biological significance of lactarane sesquiterpenes from the European mushroom Russula nobilis

The results of the first investigation on secondary metabolites occurring in intact and damaged fruiting bodies of Russula nobilis growing in Europe, are reported. Intact mushrooms contain fatty acid esters of velutinal, while three new sesquiterpenoids, russulanobilines A–C, along with eight known ones were isolated from extracts of injured fruiting bodies. The structures of the new compounds were elucidated on the basis of spectral data, molecular modeling, and 13C NMR spectra calculation. This pattern of sesquiterpenes constitutes a new variant of a chemical defense machinery which protects mushrooms against predators, parasites, and microorganisms.