Studying the polyphenols of grapevine leaves according to age and insertion level under controlled conditions

Grapevine (Vitis vinifera L.) leaf samples of three defined age groups were investigated for concentration of selected sixteen polyphenols implementing the developmental stage of leaves. All in all, twelve polyphenols were detected above the limit of quantification with caftaric acid showing the highest concentrations. By studying differences in concentrations levels of individual polyphenols between the leaves’ position on the shoot (insertion levels) trans- and cis-resveratrol-3-O-glucoside, (+)-catechin, caftaric acid, quercetin-3-O-glucoside and quercetin-3-O-glucuronide were identified as key markers with different concentrations on at least three of four sampling dates and analysed by LC–MS/MS.For future applications, the detected temporal polyphenolic pattern needs to be validated using additional cultivars of grapevine to establish a ‘polyphenolic fingerprint’ of grapevine leaves of different insertion levels.

► Grapevine leaf samples were tested for their concentration of polyphenols.
► Polyphenols showed to differ between defined age groups and insertion levels.
► Six polyphenols were detected as key markers for the age of grapevine leaves.
► These six polyphenols are combined to a polyphenolic marker set.
► The developed marker set is a useful tool to collect sources for polyphenols.