Supplemental Figure 1. Representative HPLC–UV profiles for the standard solutions used to
determine stilbene derivatives in extracts from grape Vitis amurensis before (a) and after 2 hours
(b) sunlight exposure. The characteristic UV spectra of cis isomers detected in the extracts (and
those of trans isomers for comparison), recorded from the peak tops with a DAD detector, are
shown with the imposition. The peaks are numbered as shown in Fig. 1.
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Supplemental Figure 2. The typical MS/MS2 spectra of piceid and viniferin isomers obtained in
the negative ion mode using the ion trap mass spectrometer and recorded from the peak tops.
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Supplemental Figure 3. Segment of HPLC–UV profile, recorded at 310 nm, for the extract
from grape Vitis amurensis leaves collected in October, demonstrates the presence of three major
compounds: Q1, Q2 and Q3. The characteristic UV spectra of Q1, Q2 and Q3, recorded from the
peak tops with a DAD detector, are shown with the imposition.
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Supplemental Figure 4. The MS and MS2 spectra of Q1, Q2 and Q3 obtained in the negative
ion mode using the ion trap mass spectrometer and recorded from the peak tops.
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Analytical chromatography
All solvents were of high performance liquid chromatography (HPLC) grade. Analytical
standards: t-resveratrol, t-piceid, and pterostilbene were obtained from Sigma-Aldrich (St. Louis,
MO, USA); ε-viniferin was obtained from Panreac AppliChem (GmbH, Darmstadt, Germany).
Dried leaves, petioles, seeds, and berry skins of V. amurensis collected in June and October
2015 were analyzed for the presence of stilbenes at the Instrumental Centre of Biotechnology
and Gene Engineering of IBSS FEB RAS. HPLC with MS and UV detection (HPLC-MS-UV)
for identification and quantification of all components was performed using an 1260 Infinity
analytical HPLC system (Agilent Technologies, Santa Clara, California, USA), equipped with a
G1315D photodiode array detector, G1311C quaternary pump, G1316A column oven and
G1329B auto sampler. The HPLC system was connected with a Bruker HCT ultra PTM
Discovery System (Bruker Daltonik GmbH, Bremen, Germany), equipped with ion trap mass
spectrometer. The extracts were separated on Zorbax C18 column (150 mm, 2.1-mm i.d., 3.5-μm
part size, Agilent Technologies, USA); the column temperature was 40°C. The mobile phase
consisted of a gradient elution of 0.1% aqueous acetic acid (A) and acetonitrile (B). The gradient
profile with a flow rate of 0.2 mL/min was: 0 min 0% B; 35 min 40% B; 40 min 50% B. 50 min
100% B and then eluent B until 60 min. The injected volume was 1-5 μL. The MS analysis was
carried out with electrospray ionization (ESI) and negative ions detection. The following settings
were used: the range of m/z detection was 100-1,000, the drying gas (N2) flow rate was 8 L/min,
the nebulizer gas (N2) pressure was 175 kPa, the ion source potential was -4.0 kV and the drying
gas temperature was 325°C. Tandem mass spectra were acquired in Auto-MSn mode (smart
fragmentation) using a ramping of the collision energy. The fragmentation amplitude was set to 1
V. If necessary, MS2 experiments were performed only for the precursor ions of the monitoring
compounds. UV spectra were recorded in the 200 – 400 nm range and chromatograms for
quantification were acquired at 310 nm and 285 nm for trans- and cis- isomers respectively.
Each quantification measurement was performed in duplicate.
Identification and quantification
Cis isomers of each stilbene were obtained under sunlight exposure of the respective
standard solution containing the trans isomer as reported earlier (Romero-Pérez et al. 1999;
Pezet et al. 2003). Almost 90% isomerisation was obtained after 3 h of exposure. Cis isomers of
stilbenes are not available commercially. In order to define cis-piceid in our samples, the
standard solutions of it were prepared and determined by comparison of the UV and MS data
with information previously published (Vian et al. 2005; Huang and Mazza 2011). The MS2 and
MS3 fragmentation patterns of cis-piceid were identical with those of trans-isomer obtained
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under the same MS conditions. The concentrations of cis-piceid were calculated from the
difference between the concentrations before and after sunlight exposure of the trans-isomer.
In order to define cis-piceid and cis-ε-viniferin in our samples, the standard solutions of
them were prepared and cis isomers were determined by comparison of the UV and MS data
(Supplementary materials) with information previously published (Pezet et al. 2003; Vian et al.
2005; Mulinacci et al. 2010; Huang and Mazza 2011). Multistage MS analysis (MS2 and MS3, if
necessary) for all components of the resulting mixture were realized, target fragmentation spectra
were obtained in the negative ion mode using the ion trap mass spectrometer. The fragmentation
patterns of cis isomers were similar with those of trans isomers obtained under the same MS
conditions. The concentrations of cis isomers were calculated from the difference between the
concentrations before and after sunlight exposure of the trans-isomers.
All determined components of the extracts (Fig. 1) were identified as we described recently
(Aleynova et al. 2016) on the base of UV spectra, recorded with a DAD detector, mass spectral
data and chromatographic separation with reference to the values of their respective standards.
The contents of each component were determined using by external standard method using the
four-point regression calibration curves built with the reference standards.
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