Microglia have multiple functions in regulating homeostasis of the central nervous system. Microglia cells have been implicated as active contributors to neuron damage in neurodegenerative disorders. In this study, medicinal plant extracts (MPEs) were used to evaluate the cell-death induction effect in microglia BV-2 cells. Among 35 MPEs tested in this study, 4 MPEs showed less than a 30% cell survival after 24 hours of incubation. These were Foeniculi Fructus, Forsythiae Fructus, Zingiberis Rhizoma and Hedera Rhombea. The concentration showed that 50% cell death (IC50) occurred with 33, 83, 67 Ed highlight: Please confirm wording, and 81 μ /ml, respectively. For further study, we chose Zingiberis Rhizoma (ZR) which showed a reasonably low IC50 value and an induction of cell death in a relatively narrow range. Western blot analysis showed that ZR-treated cells showed activation of caspase-3 and cleavage of PARP Ed highlight: When an acronym is first presented it needs to be spelled out in both dose- and time-dependent manners. However, the level of Bcl-2 and Bax were not changed by ZR-treatment in BV-2 cells. These results suggest that ZR-induced apoptosis in BV-2 cells occured through caspase-3 activation. The results also suggested that ZR may be useful in developing treatments for neurodegenerative diseases.

Inflammation in the brain has known to be associated with the development of a various neurologiacal diseases. The hallmark of neuro-inflammation is the activation of microglia, brain macrophage. Pro-inflammatory compounds including nitric oxide(NO) are the main cause of neuro-degenerative disease such as Alzheimer"s disease. In the study, we examined whether Harmonia axyridis extracts inhibit the NO production by a direct method using Griess reagent, western blotting and by RT-PCR(Reverse Transcription-Polymerase Chain Reactionin) the gene expression of inducible nitric oxide synthase(iNOS). Distilled water(H₂O) and methanol(MeOH) extracts of H. axyridis inhibited the protein expression of TNF-α(Tumor Necrosis Factor) and IL-6(Interleukin) in LPS (Lipo-polysaccharide) stimulated BV -2 cells at the concentration of 100 ng/㎖. Incubation of BV-2 cells with the extracts of H₂O of MeOH inhibited the LPS induced NO and iNOS protein. And this inhibition of iNOS protein is concordant with the inhibition of iNOS mRNA expression. These data suggested that H. axyridis extracts may play a crucial role in inhibiting the NO production.