Table 1.

Effect of protocatechuic acid on the inhibition of nitric oxide production in RAW 264.7 macrophages

Protocatechuic (μM)	Inhibition of NO production (%)
	LPS 1 μg/mL	LPS 1 μg/mL + IFN-γ 1,000 U/mL
25	16.2 ± 3.3*	4.3 ± 1.3*
50	21.3 ± 3.4*	6.1 ± 0.3*
100	27.4 ± 5.7*	12.7 ± 3.3*

Cells were pre-treated with protocatechuic acid for 3 h and then stimulated for 24 h with LPS (1 μg/mL) or LPS (1 μg/mL) + INF-γ (1,000 U/mL). Data were compared to activated controls treated with LPS 1 μg/mL (62.9 ± 20.2 nmol/mg protein) or LPS 1 μg/mL + IFN-γ 1,000 U/mL (101.1 ± 9.0 nmol/mg protein). Data derived from at least three independent experiments performed in triplicate and are expressed as means ± SD

* Statistical significance: P < 0.05 comparing the value with control