FIGURE 3.

Differential activations of different transcriptional responses by baicalin and baicalein. A, activation effects of baicalin and baicalein on different signaling pathways were tested using different representative reporter constructs. pERE-Luc (three repeats of estrogen-response element (ERE) placed upstream of a firefly luciferase gene) was used to test the effect on estrogen receptor signaling; pWRE-Luc (six repeats of the WRE) (TCF of 5′-GAT CAA A-3′) was used to test the effect on Wnt/β-catenin signaling; and a full-length human Runx2 promoter construct named pRunx2-Luc was used to test the effects on osteogenic differentiation. B, cultured osteoblasts were transiently transfected with three constructs for 24 h; different doses of baicalin and baicalein were applied for 48 h, and the cell lysates were collected for luciferase assay. C, cultured osteoblasts were transiently transfected with three constructs as in B and treated with baicalin and baicalein at different time points before collecting for luciferase assay. Values are expressed as the fold of increase to basal reading (control culture treated with 0.02% DMSO) and are means ± S.E., where n = 5, each with triplicate samples.