This invention relates to methods of inducing dephosphorylation of a hyperphosphorylated cell cycle regulatory protein in a tumor cell in which hyperphosphorylation of said protein contributed to cell transformation, the method comprising contacting the tumor cell with a procyanidin oligomer of five monomeric units connected via a C-4.fwdarw.C-8 linkage. Examples of such compounds are [EC-(4.beta..fwdarw.8)].sub.4-EC, and [EC-(4.beta..fwdarw.8)].sub.3-EC-(4.beta..fwdarw.8)-C, wherein EC is epicatcchin and C is catechin.

Mars, Incorporated

Methods and compositions for treating cancer

Various processes are disclosed for preparing procyanidin oligomers having (4,8)-interflavan linkages. In an improved process, a tetra-O-protected-epicatechin or -catechin monomer or oligomer is coupled with a protected, C-4 alkoxy-activated-epicatechin or -catechin monomer in the presence of an acidic clay instead of a Lewis acid. In a second process, a 5,7,3',4'-tetra-O-protected or preferably penta-O-protected-epicatechin or -catechin monomer or oligomer is reacted with a tetra-O-protected or preferably penta-O-protected-epicatechin or -catechin monomer having a thio activating group at the C-4 position; the coupling is carried out in the presence of silver tetrafluoroborate. In third process, two molecules of a penta-O-protected-epicatechin or -catechin monomer activated with a 2-(benzothiazolyl)thio group at the C-4 position are self-condensed in the presence of silver tetrafluoroborate. An improved two-step process for preparing a C-4 alkoxy activated tetra-O-benzyl-protected, 8-bromo-blocked-epicatechin or -catechin monomer is also provided. The use of naturally-derived and synthetically-prepared procyanidin (4.beta.,8).sub.4-pentamers to treat cancer is also disclosed.

procyanidin oligomer/zhubný nádor

Methods and compositions for treating cancer

Synthesis of oligomeric epicatechin and catechin-derived procyanidins

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