Table 1.

The inhibitory effect of norfloxacin and moxifloxacin on mushroom tyrosinase activity

Analyzed drug	Inhibition ± S.E.Ma (%)	ICb50 (mM)
Norfloxacin 0.005 mM	77.3 ± 3.4	0.70
Norfloxacin 0.05 mM	67.7 ± 2.1
Norfloxacin 0.5 mM	53.4 ± 2.3
Norfloxacin 1.0 mM	44.7 ± 3.6
Moxifloxacin 0.005 mM	76.6 ± 1.3	1.20
Moxifloxacin 0.05 mM	70.9 ± 1.7
Moxifloxacin 0.5 mM	61.8 ± 3.1
Moxifloxacin 1.0 mM	56.1 ± 2.5

^aSamples-contained phosphate buffer with different norfloxacin or moxifloxacin concentrations, mushroom tyrosinase (1,000 units), and L-DOPA solution (2 mg/ml). Tyrosinase activity was measured as described in “Materials and methods” section

^b50 % inhibitory concentration