Table 1.

Showing cell signalling pathways targeted by different flavonoids. Shows the effect of flavonoids observed in various cell signalling pathways. The activation of ERK, Akt/PKB, PI3K, and PKC is important to improve the cell survival, and the down-regulation of P38 and JNK is preventing the apoptosis. The activation of signalling pathways is shown as up arrow (↑) and down-regulation of signalling pathways by flavonoids is shown in down arrow (↓)

S. no.	Flavonoids	Activation (↑), deactivation (↓)	Signalling pathways	Cell line	Response	References
01	ECG	↓	P38	HaCaT keratinocytes, endothelial, rat primary hepatocytes, Chinese hamster lung fibroblast (V79-4) cells, BV2 microglial cells, neuronal cells	Prevent apoptosis, oxidative stress, and endothelial barrier dysfunction, as neuroprotective, for treatment of chronic pain and neuroinflammatory diseases, improve cognitive function, and mitochondrial functions	Choi et al. (2005), Huang et al. (2007), Yang et al. (2010), Hwang and Yen (2009), Huang et al. (2013), Meottia et al. (2007), Park et al. (2011), Liu et al. (2012)
	EGCG	↓
	Quercetin	↓
	Hesperetin	↓
	Luteolin	↓
	Myricitrin	↓
	Myricetin	↓
	Kaempferol	↓
	Pinocembrin	↓
	Narirutin	↓
02	ECG	↓	JNK	HaCaT keratinocytes, endothelial, neuronal, Chinese hamster lung fibroblast (V79-4) cells, BV2 microglial cells	Prevent oxidative stress and apoptosis, neuroprotective, for treatment of neuroinflammatory diseases	Huang et al. (2007), Choi et al. (2005), Hwang and Yen (2009), Park et al. (2011)
	EGCG	↓
	Quercetin	↓
	Hesperetin	↓
	Myricetin	↓
	Kaempferol	↓
03	EC	↑	ERK1/2	Neuronal, HaCaT keratinocytes, endothelial cells	Improve brain function, prevent oxidative stress, apoptosis	Schroeter et al. (2007), Huang et al. (2007), Choi et al. (2005)
	ECG	↑
	EGCG	↑
04	EC	↑	Akt/PKB	Neuronal, epithelial, (MCF10A, pancreatic, Chinese hamster lung fibroblast (V79-4) cells PAECs, MC3T3-E1	Improve brain function, antioxidant defence, neuroprotective, prevent oxidative stress-induced apoptosis, stimulate eNOS activity, antidiabetic, regulate mitochondrial function	Schroeter et al. (2007), Na et al. (2008), Hwang and Yen (2009), Fu et al. (2010), Vauzour et al. (2007), Yang et al. (2010), Zhanga and Liu (2011), Choi (2011)
	EGCG	↑
	Hesperetin	↑
	Myricetin	↑
	Genistein	↑
	Kaempferol	↑
05	EGCG	↑	PKC	Brain cell	Neuroprotective	Levites et al. (2002)
06	EGCG	↑	PI3K	Brain cell, Chinese hamster lung fibroblast (V79-4) cells, PC12, endothelial, PAECs	Neuroprotective, prevents oxidative stress-induced apoptosis, protect oxidative damage, stimulate eNOS activity, promote the activity of eNOS	Levites et al. (2002), Luo et al. (2012), Xi et al. (2012), Yang et al. (2010), Zheng et al. (2012)
	Quercetin	↑
	Myricetin	↑
	Genistein	↑
	Kaempferol	↑
	Naringenin	↑

MAPK mitogen-activated protein kinase, Akt/PKB protein kinase B, ERK extracellular signal-regulated protein kinase, JNK c-Jun N-terminal kinase, PI3K phosphatidylinositol-3 kinase, PKC protein kinase C, EC (−)epicatechin, ECG (−)-epicatechin-3-gallate, EGCG (−)-epigallocatechin-3-gallate, PAECs porcine aortic endothelial cells, Nrf2 nuclear factor erythroid 2-related factor 2