Daphnetin (7,8-dihydroxycoumarin), one coumarin derivative isolated from plants of the Genus Daphne, is a protein kinase inhibitor, with IC50s of 7.67 μM, 9.33 μM and 25.01 μM for EGFR, PKA and PKC in vitro, respectively[1][2]. Daphnetin (7,8-dihydroxycoumarin) is a secondary metabolite of plants used in folk medicine to counter inflammatory and allergic diseases, also has been clinically used in the treatment of coagulation disorders, rheumatoid arthritis with anti-malarian and anti-pyretic properties[3].
References:
[1]. Yang EB, et al. Daphnetin, one of coumarin derivatives, is a protein kinase inhibitor. Biochem Biophys Res Commun. 1999 Jul 14;260(3):682-5.
[2]. Lv H, et al. Daphnetin-mediated Nrf2 antioxidant signaling pathways ameliorate tert-butyl hydroperoxide (t-BHP)-induced mitochondrial dysfunction and cell death. Free Radic Biol Med. 2017 May;106:38-52.
[3]. Jiménez-Orozco FA, et al. Differential effects of esculetin and daphnetin on in vitro cell proliferation and in vivo estrogenicity. Eur J Pharmacol. 2011 Oct 1;668(1-2):35-41.