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A: Signal at 108.4 ppm in the 13C-spectrum of the “regular” PAs indicating the presence of monomeric flavan-3-ols with trihydroxylated B-rings; B: 76–85 ppm of the 13C-NMR spectra of the “regular” (upper) and “unusual” (lower) PAs. The area of 76–78 ppm is representative for the C-2 of 2,3-cis configurated flavan-3-ol units. The signals of 2,3-trans configurated units would appear in between 82 and 84 ppm.
