• the Korean Society for Brain and Neural Sciences


Original Article

Exp Neurobiol 2013; 22(2): 107-115

Published online June 30, 2013

© The Korean Society for Brain and Neural Sciences

Glycyrrhizin Attenuates Kainic Acid-Induced Neuronal Cell Death in the Mouse Hippocampus

Lidan Luo, Yinchuan Jin, Il-Doo Kim and Ja-Kyeong Lee*

Department of Anatomy, Inha University School of Medicine, Incheon 400-712, Korea

Correspondence to: *To whom correspondence should be addressed.
TEL: 82-32-890-0913, FAX: 82-32-884-2105


Glycyrrhizin (GL), a triterpene that is present in the roots and rhizomes of licorice (Glycyrrhiza glabra), has been reported to have anti-inflammatory and anti-viral effects. Recently, we demonstrated that GL produced the neuroprotective effects with the suppression of microglia activation and proinflammatory cytokine induction in the postischemic brain with middle cerebral artery occlusion (MCAO) in rats and improved motor impairment and neurological deficits. In the present study, we investigated whether GL has a beneficial effect in kainic acid (KA)-induced neuronal death model. Intracerebroventricular (i.c.v.) injection of 0.94 nmole (0.2 µg) of KA produced typical neuronal death in both CA1 and CA3 regions of the hippocampus. In contrast, administration of GL (10 mg/kg, i.p.) 30 min before KA administration significantly suppressed the neuronal death, and this protective effect was more stronger at 50 mg/kg. Moreover, the GL-mediated neuroprotection was accompanied with the suppression of gliosis and induction of proinflammatory markers (COX-2, iNOS, and TNF-α). The anti-inflammatory and anti-excitotoxic effects of GL were verified in LPS-treated primary microglial cultures and in NMDA- or KA-treated primary cortical cultures. Together these results suggest that GL confers the neuroprotection through the mechanism of anti-inflammatory and anti-excitotoxic effects in KA-treated brain.

Keywords: glycyrrhizinic acid, KA, neuroprotection, anti-inflammation