Table 2.

Potential mechanisms of caffeine, caffeic acid, chlorogenic acids, and kahweol on antitumor activity.

Type of Cancer	Cell Line	Chemical Form of Substances	Effect	Mechanism	Reference
Human colorectal cancer	HT29	Caffeine	Decrease in proliferation and migration potential	↓ HIF-1α, VEGF	Merighi et al. [93]
				↓ ERK1/2, p38, Akt
Human colorectal cancer	HCT116	Caffeine	Induction of apoptosis	G2 phase arrest	Saito et al. [118]
	transduced with Ad-PTEN			↓ Akt kinase
Human colorectal cancer	RKO	Caffeine	Increase in radiosensitivity of tumor cells	↓ Radiation-induced activation of ATM kinase	Choi et al. [119]
				↓ Activation of Chk2 kinase
				↓ Accumulation of cells in G2 phase
Human colon carcinoma	HT-29	Caffeic acid	Decrease of proliferation and viability	↑ G0/G1 phase arrest	Murad et al. [133]
		Chlorogenic acid	Increase of apoptosis;
Mouse colorectal carcinoma	CT26	Caffeic acid conjugated with chitosan	increase in apoptosis and necrosis	Unknown	Lee et al. [139]
			Decrease in proliferation and invasion;
			decrease in viability
Human colorectal cancer	HCT116	Chlorogenic acid	Decrease in cell viability and proliferation	↑ S phase arrest	Hou et al. [164]
				↑ ROS production
	HT29			↑ p53 Phosphorylation
				↓ ERK Phosphorylation
				↓ Tyrosinase activity
Human colon cancer Human liver cancer	Caco-2	Chlorogenic acid	Decrease of proliferation	Unknown	Wang et al. [165]
	HepG2
Human colorectal cancer	HT-29	Kahweol	Decrease of viability	↑ Cleaved PARP	Choi et al. [177]
				↑ caspase-3
			Increase in apoptosis	↓ Bcl-2
				↓ Phosphorylated Akt
Human colorectal cancer	HCT116 SW480	Kahweol	Inhibition of cell growth and proliferation	↑ JNK Phosphorylation	Park et al. [181]
				↑ GSK3β Phosphorylation
				Phosphorylation
				↓ Cyclin D1protein level
Human colorectal cancer	HCT116	Kahweol	Increase of apoptosis	↑ ATF3 protein level	Park et al. [186]
	SW480
	LoVo
	HT-29