Table 1.

Fold differences of thiol concentrations in media between cells treated with highest, non-toxic concentrations of drugs and non-treated control cells.

Drugs	GSH	CysGly	Hcys	Ratio GSH:CysGlya
LA	1.4⁎⁎	1.2⁎	1.6	1.2
TBHQ	1.5⁎⁎	1.3⁎	0.9	1.2
SFN	2.4⁎⁎	1.7⁎⁎	1.0	1.4
PC-Res	1.6⁎⁎	1.3	1.0	1.2

Concentrations of lipoic acid (LA), tert-butylhydroquinone (TBHQ), sulforaphane (SFN) and Polygonum cuspidatum extract containing 50% resveratrol (PC-Res) used to treat cells were 50 µM, 10 µM, 10 µM and 3.9 µg/ml.

^aRatio represents fold change in glutathione (GSH) divided by fold change in cysteinylglycine (CysGly).

^⁎Designate significant differences (p<0.05) to the non-treated control.

^⁎⁎Designate significant differences (p<0.001) to the non-treated control.