Fig 3. Effect of crude extracts on cell viability.

Primary astrocytes (1×10⁵ cells/ml), were activated with LPS (10 μg/ml) and simultaneously treated with the sponge extract from T. aurantium (Ta), T. citrina (Tc), H. perlevis (Hp), I. variabilis (Iv), C. nucula (Cn), A. aerophoba (Aa) and S. spinosulus (Ss) at the indicated concentrations. After 24 h of incubation at 37°C, 5% CO₂ astrocytes were subjected to the MTT assay. The results are expressed as percentage of surviving cells over untreated cells. Data are presented as mean ± SD of three different experiments with independent cell populations. The horizontal dashed line, set at 60%, indicates the threshold of cell viability. Concentrations of the crude extracts that yielded cell viability values < 60% of control were considered as toxic doses.