A newly published study in Scientific Reports describes the identification and characterization of alternariol monomethyl ether (AME), a fungal secondary metabolite isolated from Alternaria alternata, with potent antiproliferative activity linked to inhibition of both DNA Topoisomerase I and II. Importantly, the investigators utilized TopoGEN’s plasmid relaxation and kDNA decatenation assay systems to quantify enzyme inhibition kinetics and demonstrate dual topoisomerase targeting activity. The study reported nanomolar inhibition of Topo II (IC50 10.2 nM) and Topo I (IC50 16.7 nM), accompanied by strong apoptosis induction and cell-cycle arrest in MCF-7 breast cancer cells. These findings further reinforce the value of robust biochemical topoisomerase assays in natural product drug discovery, mechanistic oncology research, and validation of emerging DNA damage-inducing compounds. We congratulate the authors on this elegant and comprehensive study.

El-Sayed, A.S.A., Aboelez, M.O., Ezelarab, H.A.A. et al. Characterization of Alternaria alternata alternariol monomethyl ether with a potential antiproliferative activity by topoisomerases inhibition; molecular docking and dynamic simulations. Sci Rep 16, 15352 (2026). https://doi.org/10.1038/s41598-026-51757-8