The phenols and prodelphinidins of white clover flowers

White clover flowers (Trifolium repens L.) contain an abundance of phenolics, namely cis- and trans-p-coumaric acid 4-O-beta-D-glucopyranoside, the 3-O-beta-D-galactopyranosides of myricetin, quercetin and kaempferol together with two new derivatives namely myricetin 3-O-(6 -acetyl)-beta-D-galactopyranoside and kaempferol 3-O-(6 -acetyl)-beta-D-galactopyranoside. Gallocatechin, epigallocatechin, gallocatechin-(4 alpha-8)-epigallocatechin and their corresponding prodelphinidin polymers were also present. The C-13-NMR spectra showed that the polymers consisted of only gallocatechin and epigallocatechin monomeric units with the latter being about twice as abundant in the extenders but only slightly more than that in the terminating units. The average degree of polymerization was estimated by C-13-NMR and ES-MS, which gave a remarkably consistent result of about 5.8 flavanol units. (C) 2000 Elsevier Science Ltd. All rights reserved.