The flavonoids of leek, Allium porrum

A phytochemical investigation of the extracts obtained from bulbs of leek, Allium porrum L. has led to the isolation of five flavonoid glycosides base d on the kaempferol aglycone. Two of them are new compounds and have been i dentified as kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinnamoyl)-beta -D-flucopyranoside, and kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinna moyl)-beta -D-glucopyranosyl]-(1 -->4)-O-beta -D-glucopyranoside on the bas is of spectroscopic methods. including 2D NMR. The isolated compounds have been evaluated for their human platelet anti-aggregation activity. (C) 2001 Elsevier Science Ltd. All rights reserved.