Effect of diets fortified with tomatoes or onions with variable quercetin-glycoside content on azoxymethane-induced aberrant crypt foci in the colon of rats

TY - JOUR

T1 - Effect of diets fortified with tomatoes or onions with variable quercetin-glycoside content on azoxymethane-induced aberrant crypt foci in the colon of rats

AU - Femia, A.P.

AU - Caderni, G.

AU - Ianni, M.

AU - Salvadori, M.

AU - Schijlen, E.G.W.M.

AU - Collins, G.

AU - Bovy, A.G.

AU - Dolara, P.

PY - 2003

Y1 - 2003

N2 - Background: Onion and tomato are vegetables widely consumed by humans and epidemiological studies show an inverse association between vegetable consumption and colon cancer risk; however, the effect on colon cancer of diets containing high levels of vegetables like onion and tomato are not clear. Aims of the study: To investigate whether tomatoes and onions,with low or high quercetin-glycoside content, could reduce azoxymethane (AOM)-induced Aberrant Crypt Foci (ACF), preneoplastic lesions in the colon of rats. Methods: Male Fisher 344 rats were fed the following diets: a) high fat (HF) diet (control diet); b) HF diet containing 20 % (w/w) tomatoes with a low quercetin-glycoside content (final concentration in the diet: 5 mg/kg of quercetin aglycone equivalents); c) HF diet containing 20% (w/w) high quercetin-glycoside tomatoes (100 mg/kg final concentration of quercetin aglycone equivalents); d) HF diet containing 20 % (w/w) low quercetin-glycoside onions (14 mg/kg of quercetin aglycone equivalents in the diet); e) HF diet containing 20 % (w/w) high quercetin-glycoside onions (360 mg/kg quercetin aglycone equivalents in the diet). After 2 wks of feeding, all rats were treated twice, 1 wk apart, with AOM (12 mg/kg, s. c.). The dietary treatments continued until sacrifice, 7 wks after the first injection with AOM. Results: ACF induction did not vary in animals fed low or high quercetin-glycoside tomatoes relative to controls. On the contrary, rats fed 20% (w/w) onion-based diets, with low or high quercetin-glycoside content, showed an increase in number, multiplicity and large ACF compared to the control group (number of ACF/colon 145 ± 15 (SE), 255 ± 11 and 218 ± 16 in controls, low and high-quercetin-glycoside groups, respectively; p <0.01). Proliferative activity of the colon did not vary between animals fed control and high quercetin-glycoside tomato diet. The height of the crypts in normal mucosa of rats fed high quercetinglycoside onions was significantly increased compared to control rats (cells/emicrypt 38.4 ± 1.2 (SE) and 41.3 ± 0.6 in controls and high quercetin-glycoside onions group, p <0.05). Conclusions: None of the diets supplemented with onion or tomato with variable quercetin-glycoside content demonstrated a potential chemopreventive effect on ACF-induction by AOM in rats

AB - Background: Onion and tomato are vegetables widely consumed by humans and epidemiological studies show an inverse association between vegetable consumption and colon cancer risk; however, the effect on colon cancer of diets containing high levels of vegetables like onion and tomato are not clear. Aims of the study: To investigate whether tomatoes and onions,with low or high quercetin-glycoside content, could reduce azoxymethane (AOM)-induced Aberrant Crypt Foci (ACF), preneoplastic lesions in the colon of rats. Methods: Male Fisher 344 rats were fed the following diets: a) high fat (HF) diet (control diet); b) HF diet containing 20 % (w/w) tomatoes with a low quercetin-glycoside content (final concentration in the diet: 5 mg/kg of quercetin aglycone equivalents); c) HF diet containing 20% (w/w) high quercetin-glycoside tomatoes (100 mg/kg final concentration of quercetin aglycone equivalents); d) HF diet containing 20 % (w/w) low quercetin-glycoside onions (14 mg/kg of quercetin aglycone equivalents in the diet); e) HF diet containing 20 % (w/w) high quercetin-glycoside onions (360 mg/kg quercetin aglycone equivalents in the diet). After 2 wks of feeding, all rats were treated twice, 1 wk apart, with AOM (12 mg/kg, s. c.). The dietary treatments continued until sacrifice, 7 wks after the first injection with AOM. Results: ACF induction did not vary in animals fed low or high quercetin-glycoside tomatoes relative to controls. On the contrary, rats fed 20% (w/w) onion-based diets, with low or high quercetin-glycoside content, showed an increase in number, multiplicity and large ACF compared to the control group (number of ACF/colon 145 ± 15 (SE), 255 ± 11 and 218 ± 16 in controls, low and high-quercetin-glycoside groups, respectively; p <0.01). Proliferative activity of the colon did not vary between animals fed control and high quercetin-glycoside tomato diet. The height of the crypts in normal mucosa of rats fed high quercetinglycoside onions was significantly increased compared to control rats (cells/emicrypt 38.4 ± 1.2 (SE) and 41.3 ± 0.6 in controls and high quercetin-glycoside onions group, p <0.05). Conclusions: None of the diets supplemented with onion or tomato with variable quercetin-glycoside content demonstrated a potential chemopreventive effect on ACF-induction by AOM in rats

KW - chemopreventive agents

KW - f344 rats

KW - cancer

KW - carcinogenesis

KW - consumption

KW - acid

KW - chalcone

KW - rectum

KW - fruit

KW - rutin

U2 - 10.1007/s00394-003-0431-5

DO - 10.1007/s00394-003-0431-5

M3 - Article

VL - 42

SP - 346

EP - 352

JO - European Journal of Nutrition

JF - European Journal of Nutrition

SN - 1436-6207

IS - 6

ER -