Damnacanthal is a potent and inhibitor of p56lck tyrosine kinase and inhibits autophosphorylation with IC50 of 17 nM and phosphorylation of exogenous substrates with IC50 of 620 nM in cell free assays. Damnacanthal Displays 7- to 20-fold selectivity over p59fyn and p60src tyrosine kinases, > 40-fold selectivity over c-ErbB2, EGF- and insulin-receptor tyrosine kinases, and > 100-fold selectivity over PKA and PKC. Mobilizes intracellular Ca2+ in dermal fibroblasts and inhibits Ras function. Also inhibits LIMK1/2, as well as migration and invasion of breast cancer cells in vitro. MW: 282.25. Purity ≥98% by HPLC