TDP1 and cancer: Because of the plant's historic significance and documented chemical variety, several biological actions of plant extracts and/or metabolites involving anti-cancer activity have been reported6–8,10,11 and the inhibition of DNA topoisomerase IB (TOP1) and tyrosyl-DNA phosphodiesterase 1 (TDP1).8,9 Longikaurin A from I. ternifolius exerted anticancer activity against several cancer cell lines, specifically hepatocellular carcinoma cells.10