Antioxidant Effects of Protocatechuic Acid and Protocatechuic Aldehyde: Old Wine in a New Bottle

Table 2

Summary of the effects on antioxidants of PCA and PAL in vitro.

Disease model	PCA/PAL dosages	Model used	Oxidative stress mechanisms	References
Neurodegenerative diseases	PCA (50, 100, 150, and 200 μg/ml)	H2O2-treated PC12 cells	Downregulation of lipid peroxidation and upregulation of glutathione peroxidase and superoxide dismutase activity	[118]
PD	PAL (20 μM)	H2O2-treated SH-SY5Y cells	Activation of the Akt pathway and suppression of excessive DJ-1 oxidation	[95]
PD	PCA (1 mM)	6-OHDA-treated PC12 cells	Activation of Nrf2/HO-1 and suppression of NF-κB signaling	[102]
PD	PCA (10 μM)	MPP-treated SH-SY5Y cells	Mitigation of oxidative damage and mitochondrial dysfunction through PLK2/p-GSK3β/Nrf2 pathway	[101]
PD	PAL (1, 10, and 100 μM/0.1, 1, and 10 μM)	H2O2/6-OHDA-treated PC12 cells	Induction of DJ-1 and reduction of a-synuclein expression	[100]
Diabetic cataract	PAL (20 and 50 μg/ml)	High glucose- or S100b-treated human lens epithelial cells	Inhibition of TGF-β1 expression and pSmad2/3 nuclear accumulation	[135]
Cerebral I/R injury	PAL (80 μM)	Differentiated SH-SY5Y cells	Induction of Nrf2 nuclear translocation and HO-1 upregulation	[104]
CVD	PCA (10, 50, and 100 μM)	Palmitic acid- (PA-) treated HUVECs.	Suppression of Ac-CoA or Sirt1 and Sirt3 activation through CD36/AMPK signaling	[146]
CVD	PAL (100 μM)	Thoracic aortic smooth muscle cells	Inhibition of PDGF and other cytokines cascade signaling	[15]
CVD	PCA (10–100 μM)	PA-treated HUVECs	Induction of HO-1 and increasing SOD and GPx-1 activity through LKB1-AMPK-Nrf2 pathway	[145]
Atherosclerosis	PAL (10, 50, or 100 μM)	HUVECS	Reduction of ROS activity and inflammation, increase of cAMP and GPER-1	[143]
Ischemic injury	PCA (10, 20, and 40 μM)	H2O2 treat H9C2 cells	Reduction of ROS and elevation of GSH	[148]
Liver injury	PCA (2.5, 5, and 10 μM)	PA-treated AML-12 cells	Activation of SIRT3 and suppression of ACSF3-mediated fatty acid metabolism disorder	[150]
Liver injury	PCA (10 μM)	Primary hepatocytes, AML-12 cells	Upregulation of miR-219a-5p expression and suppression of p66shc-mediated ROS formation	[149]
Liver injury	PCA 20 ug/ml, PAL 20 ug/ml	Ccl4 treatment isolated rat hepatocytes	Inhibit MDA production in liver microsomes and peroxidative damage to the surfaces of rat hepatocytes.	[156]
Cancer	PCA (500 ppm)	N-nitroso-methyl benzylamine- (NMBA-) induced esophageal tumorigenesis	Inhibition of tumorigenesis and inflammatory signaling	[160]
Cancer	PCA (100 μM)	HepG2 hepatocellular carcinoma cells	Induction of JNK-dependent hepatocellular carcinoma cell death	[159]
Cancer	PAL (0.25, 0.5, and 1 μM)	Cisplatin-treated HK2 cells	Suppression of cisplatin-induced death through inhibition of Nox4	[164]
Pulmonary injury	PCA (25 μM)	Fluoride-treated A549 cells	Inhibition of fluoride toxicity through regulation of intracellular calcium level, bioavailability, redox signaling, and mitochondrial membrane integrity	[174]