4-Aminoethylamino-emodin--a novel potent inhibitor of GSK-3beta--acts as an insulin-sensitizer avoiding downstream effects of activated beta-catenin.

Glycogen synthase kinase-3beta (GSK-3beta) is a key target and effector of downstream insulin signalling. Using comparative protein kinase assays and molecular docking studies we characterize the emodin-derivative 4-[N-2-(aminoethyl)-amino]-emodin (L4) as a sensitive and potent inhibitor of GSK-3beta with peculiar features. Compound L4 shows a low cytotoxic potential compared to other GSK-3beta inhibitors determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and cellular ATP levels.

Differential inhibition of matrix metalloproteinases-2, -9, and -13 activities by selected anthraquinones.

Matrix metalloproteinases (MMPs) play an important role in physiological and pathological matrix remodeling. Here, we report that the natural anthraquinones, emodin, emodic acid, chrysazin, physcion, and rhein differentially inhibit several members of this enzyme family, the gelatinases MMP-2 and -9, and the collagenase MMP-13. The IC50 values determined by measuring the activities of human recombinant catalytic domains of these enzymes varied in the micromolar range.