Additional file 10 .

Biosynthesis of terpenic moiety of secoiridoids. The biosynthetic steps for the production of the terpenic moiety of oleuropein in Olea europaea according to Obied et al.[1] is reported, with some modifications. Based on our data, we propose that in the olive fruits geraniol for the secoiridoid synthesis derives from the MEP pathway. Iridoidal is produced through a series of hydroxylation and oxidation reactions on geraniol followed by a cyclisation reaction. Further oxidation yields iridotrial and deoxyloganic acid aglycone. Deoxyloganic acid is converted to 7-epi-loganic acid through the hydroxylation of the cyclopentane ring, then the hydroxyl group is oxidised to form 7-ketologanic acid. An esterification reaction is required for the conversion of 7-ketologanic acid to 7-ketologanin, and subsequently, oleoside 11-methyl ester is produced through the oxidation of the ketonic group. In a reaction catalysed by glucosyl transferase, oleoside 11-methyl ester is converted to 7-β-1-D-glucopyranosyl 11-methyl oleoside, which is the precursor of ligstroside and oleuropein.

Format: PDF Size: 99KB Download file

This file can be viewed with: Adobe Acrobat Reader

Alagna et al. BMC Plant Biology 2012 12:162   doi:10.1186/1471-2229-12-162