title: Floral procyanidins of the forage legume red clover (Trifolium pratense L.).
abstract: The chemical characteristics of the purified procyanidin polymers of the flowers of the forage legume red clover (Trifolium pratense L.) were studied by (13)C NMR, acid-catalyzed degradation with benzyl mercaptan, and electrospray ionization mass spectrometry (ESI-MS). The (13)C NMR showed that the fraction consisted of predominantly procyanidin polymers. The thiolysis reaction products indicated a mean degree of polymerization (mDP) of 9.3 with epicatechin (81%) as the abundant flavan-3-ol extension unit and the terminating units dominated by catechin (95%). ESI-MS showed a range of oligomeric procyanidin ions (DP of 2-11). The white clover floral prodelphinidins consist of terminal units with nearly equal proportions of epigallocatechin (52%) and gallocatechin (48%) and extender units showing epigallocatechin (56%) and gallocatechin (39%). The dramatic difference in the stereochemistry of the terminal and extender units observed for the red clover floral procyanidins contrasts with the mixture of cis and trans stereochemistry observed for white clover floral prodelphinidins.
authors.affiliation: Nutrition and Behavior and Plant Breeding and Genomics, AgResearch Ltd., Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand.
authors.forename: Subathira
authors.initials: S
authors.lastname: Sivakumaran
authors.forename: Lucy P
authors.initials: LP
authors.lastname: Meagher
authors.forename: Lai Yeap
authors.initials: LY
authors.lastname: Foo
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Lane
authors.forename: Karl
authors.initials: K
authors.lastname: Fraser
authors.forename: William
authors.initials: W
authors.lastname: Rumball
mesh_terms: D044946:Biflavonoids; D002392:Catechin / Q000032:analysis*; D035264:Flowers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000032:analysis; D044945:Proanthocyanidins; D021241:Spectrometry, Mass, Electrospray Ionization; D013438:Sulfhydryl Compounds / Q000378:metabolism; D029921:Trifolium / Q000737:chemistry*
chemical_list: D044946:Biflavonoids; D011108:Polymers; D044945:Proanthocyanidins; D013438:Sulfhydryl Compounds; C017674:procyanidin; D002392:Catechin