Pycnidione (CAS: 149064-34-6)

Pycnidione is a tropolone-containing meroterpenoid natural product originally isolated from fungal sources and biosynthetically formed via an intermolecular hetero Diels-Alder reaction between a tropolone polyketide and humulene. It exhibits potent antiproliferative activity in cancer cells, inducing G1 arrest and apoptosis through ROS generation, mitochondrial membrane depolarization, and caspase activation. Importantly, pycnidione abrogates DNA damage-induced G2 arrest by downregulating Chk1 and Chk2, thereby sensitizing cells to chemotherapeutic agents such as bleomycin. Recent synthetic and synthetic biology studies have clarified its stereochemistry and expanded the accessible tropolone sesquiterpenoid scaffold. Pycnidione therefore represents a valuable chemical probe for studying DNA damage checkpoints and redox-driven apoptosis.