<i>Senna alata</i> leaves are a good source of propelargonidins

<p>Proanthocyanidins (PA) in <i>Senna alata</i> leaves were investigated by thiolysis with benzyl mercaptan, LC–MS and NMR and consisted of almost pure propelargonidins with <6% procyanidins, had B-type linkages and a mean degree of polymerisation of three. Epiafzelechin was the major flavan-3-ol subunit (>94%) and epicatechin a minor constituent (6.4%) in residual PA and mainly detected as an extension unit.