C1 has no negative effect on brain cells.

a) The metabolic activity of primary cultured neonatal microglia, primary cultured neonatal astrocytes and the oligodendrocyte cell line OLN-93 was evaluated under physiological condition (unstimulated). The cells were treated for 48 hours with 2.5 μM C1 (in blue), or its corresponding concentration of DMSO (125x10-5 v/v, in grey) or plain medium (in white). DMSO (p = 0.0439) and C1 (p = 0.0402) showed a significant increase in metabolic activity on microglia compared to plain medium. Comparing DMSO and C1 showed no significant difference. DMSO and C1 showed no influence on astrocytes. C1 increased the metabolic activity in oligodendrocytes compared to DMSO (p = 0.0431) but not compared to plain medium (p = 0.2140). b) Using the same experimental setup as in Fig 3, the proliferation and cell death was measured using a propidium iodide based assy. C1 increased the proliferation in microglia significantly compared to plain medium (p = 0.0154) and DMSO (p c) DMSO increased the percentage of dead cells in microglia significantly compared to plain medium (p = 0.0096). Treatment with C1 kept the percentage of dead cells similar to plain medium (C1: 8.49%, plain medium: 8.26%) with no significant difference. However, it showed a significant reduction from the elevated DMSO level (p = 0.0201). ** p### p## p# p (PNG)