Beta-hydroxyisovalerylshikonin is a natural product isolated from Lithospermum erythrorhizon, acts as a potent inhibitor of protein tyrosine kinases (PTK), with IC50s of 0.7μM and 1μM for EGFR and v-Src receptor, respectively. Beta-hydroxyisovalerylshikonin is effective against a wide variety of tumor cell lines, and most efficiently induces cell-death in NCI-H522 and DMS114 cells.IC50 & Target:IC50: 0.7 μM (EGFR), 1 μM (v-Src)