Novel neuroprotective effects of the aqueous extracts from Verbena officinalis Linn

Verbena officinialis Linn. (Verbenaceae) is a perennial plant which has been used as herbal medicine or health supplement in both Western and Eastern countries for centuries. It has been used to treat acute dysentery, enteritis, amenorrhea and depression. In view of its wide array of biological effects. we hypothesized that V. officinalis can exert cytoprotective effects on cells of the central nervous system. Pre-treatment of aqueous extracts of V. officinalis significantly attenuated the toxicity of (beta-amyloid (A beta) peptide and reducing agent dithiothreitol in primary cultures of cortical neurons. As extracellular accumulation of A beta peptide is an important cytotoxic factor involved in Alzheimer's disease (AD), we have further explored its neuroprotective effect against A beta. Treatment of V. officinalis attenuated A beta-triggered DEVD- and VDVAD-cleavaee activities in a dose-dependent manner. Further studies elucidated that phosphorylation of both interferon-inducing protein kinase (PKR) and c-Jun N-terminal kinase (JNK) was attenuated in A beta-treated neurons. Taken together, we have proved our hypothesis by showing the novel neuroprotective effects of V. officinalis. As V. officinalis has long been used for many years to be a folk medicine, our study may provide a lead for its potential to be a neuroprotective agent against neuronal loss in AD. (c) 2005 Elsevier Ltd. All rights reserved.