2.6 In vitro cytotoxic concentration (CC50) against mammalian cells

The cytotoxicity of the compounds was determined using murine macrophages (2 × 10⁶ in 200 µL) of BALB/c mice incubated with various compound concentrations for 72 at 37°C and 5% CO₂. The effect on macrophage viability was assessed using the MTT assay. The concentration of extracts/compounds that caused 50% macrophage cytotoxicity (CC₅₀) was determined by linear regression analysis using GraphPad Prism software, version 5.0. The selectivity index (SI) of the extracts/compounds was determined using the following equation: SI = CC₅₀ against mammalian cells/IC₅₀ against L. amazonensis amastigotes.