Planta Med 2012; 78 - PI277
DOI: 10.1055/s-0032-1320964

New A-type Trimeric and tetrameric procyanidins from Peanuts skins

MK Jamróz 1, MH Davey 2, S Kaźmierski 3, W Danikiewicz 4, G Spólnik 4, JA Gliński 2
  • 1Dept. of Physical Chemistry, Medical University of Warsaw, Banacha 1, 02–042 Warsaw, Poland
  • 2Planta Analytica LLC, 39 Rose Street, Danbury, CT 06810, USA
  • 3The Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, Poland
  • 4Organic Chemistry Insitute PAS, Kasprzaka 44/52, 01–224 Warsaw, Poland

Peanut skins constitute up to 4% w/w of peanuts and are a unique source of A-type procyanidins. Methanol extract of the skins was purified by Centrifugal Partition Chromatography (FCPC Kromaton) and RP HPLC to afford pure procyanidins. They contain both epicatechin (EC) and catechin (C) subunits, which are joined through 4β-8 or 4α-6 bonds. The extract contains dimers A1 and A2 and certain tetramers > monomers > trimers. Two new tetrameric procyanidins containing two A-type bonds and one trimer, in addition to two known trimers, were isolated. The structures were established to be EC-(4β-8', 2β-O-7')-EC-(4α'-6")-EC-(4β"-8"', 2β"-O-7"')-EC (1), EC-(4β-8', 2β-O-7')-EC-(4α'-6'')-EC-(4β"-8"', 2β"-O-7"')-C (2), EC-(4β-6', 2β-O-7')-EC-(4β'-8", 2β'-O-7")-C (3), EC-(4β-8')-EC-(4β'-8'', 2β'-O-7")-C (4), EC-(4β-6')-EC-(4β'-8", 2β'-O-7")-C (5) by means of NMR and MS. Compounds (4) and (5) were previously isolated from Vaccinium vitis-idaea. Their structures differ only in the location of a linkage between upper and middle units. At 275K both 4 and 5 exist as two clearly distinguishable by NMR rotamers. The NOESY spectra at 275K with different mixing time were recorded, showing the NOESY correlations within one of the rotamers, when mixing time did not exceed 100ms and correlations between different rotamers with mixing time of 500ms.