Sesquiterpenoid spiro compounds from potato tubers infected with Phoma foveata and Fusarium spp.

Abstract

The main sesquiterpenoids found in potato tubers infected by the fungi Phoma foveata and Fusarium spp. were identified as the C-1′ epimers of (2 R,5 S,10 R)-2-(1′,2′-dihydroxy-1′-methylethyl)-6,10-dimethyl-spiro[4,5]dec-6-en-8-one and their 2′- O-β- d-glucopyranosides, by using NMR techniques, conformational analysis, CD measurements and chemical methods. The 1′ S epimers predominated. The pattern of post-infectional metabolites in the stress zone and mycelia as well as in healthy tuber tissue was monitored by HPLC.