Figure 2.

Dose‐dependent cytotoxicity of eugenol (1 h exposure) to HMEC‐1 endothelial cells, HNDF fibroblasts and 153BR fibroblasts as determined by the NR assay. Following exposure to eugenol, the medium was replaced with NR‐containing medium for 3 h, which was then removed and the cells fixed with 1% CaCl₂−0.5% formaldehyde. Cells were then lysed with 1% v/v acetic acid – 50% v/v ethanol to extract the dye, incubated for 10 min at room temperature, and read at 540 nm. Error bars indicate the standard deviation (n > 16). (The concentrations of eugenol used were proportionate to that actually present in the oil).