Identification of Licopyranocoumarin and Glycyrurol from Herbal Medicines as Neuroprotective Compounds for Parkinson's Disease

Abstract

<div><p>In the course of screening for the anti-Parkinsonian drugs from a library of traditional herbal medicines, we found that the extracts of <i>choi-joki-to</i> and <i>daio-kanzo-to</i> protected cells from MPP⁺-induced cell death. Because <i>choi-joki-to</i> and <i>daio-kanzo-to</i> commonly contain the genus <i>Glycyrrhiza</i>, we isolated licopyranocoumarin (LPC) and glycyrurol (GCR) as potent neuroprotective principals from <i>Glycyrrhiza</i>. LPC and GCR markedly blocked MPP⁺-induced neuronal PC12D cell death and disappearance of mitochondrial membrane potential, which were mediated by JNK. LPC and GCR inhibited MPP⁺-induced JNK activation through the suppression of reactive oxygen species (ROS) generation, thereby inhibiting MPP⁺-induced neuronal PC12D cell death. These results indicated that LPC and GCR derived from <i>choi-joki-to</i> and <i>daio-kanzo-to</i> would be promising drug leads for PD treatment in the future.</p></div