I want to test curcumin and sulforaphane in cell viability assays. I am planning to use tetrahydrofuran (THF) as vehicle for two reasons: 1) I have verified that these compounds are well dissolved in this solvent, 2) it has been reported in several cell lines (including one that I am using) that concentrations of 0.5% can be used per well in 96-well plates, which suggests it is less cytotoxic than other commonly used solvents, such as DMSO (maximum concentration per well = 0.1%) and ethanol (maximum concentration per well = 0.2%). But, despite this advantage, THF is less frequently used than DMSO and ethanol, not only for these compounds but in general in cell viability assays. Why is this? Are there major issues with using THF that I should know about?