Cyclo(L-Phe-trans-4-hydroxy-L-Pro) is a natural product from Phellinus igniarius.

JTK-109 is an inhibitor of hepatitis C virus NS5B RNA-dependent RNA polymerase inhibitor and inhibits G1b and G3a subgenomic replicons and recombinant enzymes.

Aristolochic acid B is one of the major components of the carcinogenic plant extract aristolochic acid, is known to be mutagenic and to form DNA adducts in vitro and in vivo.