Asarinin, an urofuran lignan, is the epimer of sesamin. Asarinin is listed in Chinese Pharmacopoeia and used as a quality control (QC) index of crude herbs by the State Food and Drug Administration of China. Asarinin exhibits several biological activities such as decreasing cholesterol levels, exhibiting antihypertensive and antiangiogenic properties and providing immunosuppressive and hepatoprotective activities. Asarinin can also inhibit myocardial injury in metabolic syndrome of rats and decrease the possibility of acute heart transplant rejection. Sesamin was first isolated from sesame seed oil, while asarinin was first isolated from prickly ash bark. Both sesamin and asarinin have been shown to act as insecticidal synergists with pyrethrins.