Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5224412 | Tetrahedron | 2009 | 7 Pages |
Proanthocyanidins, known as condensed tannins or oligomeric flavonoids, exist in many edible plants and show various interesting biological activities. We have developed a simple and versatile method of synthesizing procyanidin oligomers consisting of (â)-epicatechin and (+)-catechin. This method is applicable to the synthesis of various 3-O-substituted oligomers. We report here the stereoselective and length controlled synthesis of [4-8]-condensed (â)-epicatechin series procyanidin oligomers. We described the details of the synthesis of an two tetramers, (â)-epicatechin-(â)-epicatechin-(â)-epicatechin-(â)-epicatechin and (â)-epicatechin-(â)-epicatechin-(â)-epicatechin-(+)-catechin (arecatannin A1), (â)-epicatechin pentamer and two 3,3â³,3â-tri-O-galloyl trimers, (â)-epicatechin-(â)-epicatechin-(â)-epicatechin-3,3â³,3â-tri-O-gallate and (â)-epicatechin-(â)-epicatechin-(+)-catechin-3,3â³,3â-tri-O-gallate with the condensation method using TMSOTf as a catalyst. The ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity of these oligomeric compounds were investigated.
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