Understanding the molecular mechanisms of cancer prevention by dietary phytochemicals: From experimental models to clinical trials

Table 2 Chemopreventive efficacy of dietary phytochemicals in experimental studies

Compounds	Chemopreventive agent administered (before + during + after carcinogen treatment) route-range of dose	Prevention of carcinogen induced tumors			Pathways modulated		No. of studies reporting protection	Selected ref.
		Target organs	Tumor multiplicity/tumor incidence (#)	Latency period	Cell proliferation/apoptosis	Detoxication pathways
Tocopherols	Diet: 0.3%, 100-4000 mg/kg	Lung, Vagina, Prostate, Colon, Mammary gland	↓(3)/NR	NR	↓(3)/↑(2)	↑(2)	8	[76,77]
Indoles	Diet: 0.25%, 500- 4000 ppm, 0.014 mmol/g, 112 μmol/g, Gavage 50-250 mg/kg BW	Endometrium, Liver, Mammary gland, Lung	↓(5)/↓(2)	↑	↓(4)/↑(3)	↑(3)	14	[31]
Genistein	s.c.: 100-400 mg/mL (100 μL), Gavage: 1-500 mg/kg BW	Mammary gland, Prostate, Seminal vesicles, Buccal pouch, Uterous, Colon, Lung	↓(5)/↓(2)	NR	↓(5)/↑(3)	↑(3)	20	[78]
	Diet: 100-300 mg/kg
Curcumin	Diet: 0.05%-2%, 500-2000 ppm, Topical: 1-100, 3000 nmol	Skin, Digestive system, Intestine1, Mammary gland, Liver, Kidney, Cheek pouch, Esophagus	↓(14)/↓(8)	NR	↓(12)/↑(8)	↑(9)	23	[79-82]
Dially sulphide	i.g.: 150-200 mg/kg BW, Topical: 0.5%-1% (100 μL)	Colon, Kidney, Forestomach, Urinary bladder, Thymus, Lung, Esophagus, Buccal pouch, Skin, Liver, Colon, Kidney	↓(6)/↓(2)	NR	↓(5)/↑(3)	↑(2)	17	[83,84]
Resveratrol	Diet: 60-200 mg/kg	Urinary bladder, Skin, Mammary gland1, Buccal pouch, Tounge, Prostate, Lung, Salivary gland	↓(5)/↓(1)	↑	↓(7)/↑(6)	↑(4)	24	[85-88]
Retinoids	Topical (Oral): 0.5-1.0 mmol/kg BW	Urinary bladder, Skin, Mammary glands1, Buccal puch, Tounge, Prostate, Lung, Salivary gland	↓(6)/↓(1)	↑	-/-	NR	16	[89-91]
	Diet: 150-200 mg/kg
Capsaicin	Diet: 1% capsaicinoids (64.5% capsaicin), Topical (Oral): 10-102 mg/kg BW	Lung, Skin, Tongue, Colon	↓(4)/NR	-	↓(4)/↑(3)	NR	10	[92,93]
Phenethy isothiocyanate	Diet: 5-25 μmol/g, 0.01%-0.1%	Lung, Esophagus, Urinary bladder, Colon	↓(3)/↓(1)	NR	-/-	NR	9	[94-96]
Lycopene	Drinking water: 17 ppm	Prostate, Lung, Colon, Mammary gland1, Buccal pouch, Liver	↓(5)/↓(2)	↑	↓(4)/↑(5)	↑(5)	18	[97]
	Diet: 10-300 mg/kg Gavage: 15-20 mg/kg BW
Green, Black tea polyphenols	Drinking water: 1%-5%, 200-1000 ppm	Liver, Skin, Mammary gland, Lung, Buccal pouch, Colon, Esophagus, Prostate gland	↓(15)/↓(6)	↑	↓(9)/↑(10)	↑(8)	24	[98-104]
	Diet: 0.05%, Topical: 1-200 mg/animal

¹Spontaneous tumors. NR: Not reported; #: No. of studies reported.