(-)-Epigallocatechin gallate derivatives for inhibiting proteasome

Abstract

(-)-EGCG, the most abundant catechin, was found to be chemopreventive and anticancer agent. However, (-)-EGCG has at least one limitation: it gives poor bioavailability. This invention provides compounds of generally formula 10, wherein R₁ is selected from the group of --H and C₁ to C[sub 6] acyl group; R₂, R₃, and R₄ are each independently selected from the group of --H, --OH, and C₁ to C[sub 6] acyloxyl group; and at least one of R₂, R₃, or R₄ is --H. The derivatives of (-)-EGCG that is at least as potent as (-)-EGCG. The carboxylate protected forms of (-)-EGCG and its derivatives are found to be more stable than the unprotected forms, which can be used as proteasome inhibitors to reduce tumor cell growth.