Chemopreventive activity of isoquinoline alkaloids from Corydalis plants

Eighteen isoquinoline alkaloids including protoberberines (1-12), benzophen anthridines (13-16) and an aporphine (17) isolated from plants of Corydalis species (Fumariaceae) were tested for inhibitory effects on Epstein-Barr v irus early antigen activation induced by 12-O-tetradecanoylphorbol 13-aceta te in Raji cells. In a primary screening test, all of the isoquinoline alka loids showed inhibitory activity with the IC50 values being in the range of 140-410 mol ratio/32 pmol TPA. The data demonstrate that these isoquinolin e alkaloids might be valuable as anti-tumor promoters.