Discovery of bioactive polycyclic polyprenylated acylphloroglucinol from Hypericum patulum that protects against hepatic ischemia/reperfusion injury

Hepatic ischemia/reperfusion injury (IRI) remains a critical complication contributing to graft dysfunction following liver surgery. As part of an ongoing search for hepatoprotective natural products, five previously unreported homoadamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), named hyperhomanoons A–E (1−5), and one known analog, hypersampsone O (6), were isolated from Hypericum patulum. Among these, compound 6 demonstrated potent protective effects against CoCl₂-induced hypoxic injury in hepatocytes. Furthermore, in a murine model of hepatic IRI induced by vascular occlusion, pretreatment with 6 markedly alleviated liver damage and reduced hepatocyte apoptosis. This study is the first to identify PPAPs as promising scaffolds for the development of therapeutic agents targeting hepatic IRI, underscoring their potential as lead compounds in drug discovery efforts for ischemic liver diseases.