MTT, a tetrazolium salt, is widely used tool in cell biology for measuring cell proliferation and cytotoxicity, first reported by T. Mosmann in 1983.¹⁾ With mammalian cells, fractionation studies indicate that the reduced pyridine nucleotide cofactor (NADH) in active mitochondria, is responsible for reduction of MTT to a blue color formazan product.²⁾ Therefore, the assay detects living, but not dead cells and the signal generated is dependent on the degree of activation of the cells.³⁾