Prevention of N-methylnitrosourea-induced colon carcinogenesis in rats by oxygenated carotenoid capsanthin and capsanthin-rich paprika juice.
Epidemiological and animal studies have provided evidence that dietary carotenoids may reduce the risk of certain types of cancer. An inhibitory activity of oxygenated carotenoid capsanthin, a potent antioxidant, and paprika juice rich in capsanthin (3.54 mg/100 ml) against colon carcinogenesis was investigated in F344 rats. In Experiment I (short-term assay), six rats each were given a gavage of 5 mg, 0.2 mg, or 0.008 mg capsanthin six times a week for Weeks 2-6 after receiving three intrarectal doses of 4 mg N-methylnitrosourea in Week 1. The number of colonic aberrant crypt foci, preneoplastic lesions, at Week 6 was significantly fewer (by 42%) in the 0.2 mg capsanthin group, but not in other groups, than the control group. In Experiment II (long-term assay), five groups of 30 or 25 rats each received an intrarectal dose of 2 mg N-methylnitrosourea three times a week for Weeks 1-3, and had either of 10 p.p.m. or 2 p.p.m. capsanthin solutions, 1:2.5 and 1:16.7 diluted solution of paprika juice (containing 10 p.p.m. or 2 p.p.m. capsanthin), and tap water (control fluid) as drinking fluid throughout the experiment. The experimental groups were fed 0.2 mg or 0.04 mg capsanthin/day/rat. The colon cancer incidence at Week 30 was significantly lower in the highly diluted paprika juice group (40%), but not in the moderately diluted paprika juice group (60%) and the capsanthin solution groups (68% and 68%) than the control group (83%). The results suggested that paprika juice may affect colon carcinogenesis. However, capsanthin alone failed to inhibit colon tumorigenesis, in spite of suppression of aberrant crypt foci formation in the short-term assay. Further studies are needed to explain this discrepancy.
Narisawa
T
T
Akita University College of Allied Medical Sciences, Akita 010-8543, Japan. tomio7na@ams.akita-u.ac.jp
Fukaura
Y
Y
Hasebe
M
M
Nomura
S
S
Oshima
S
S
Inakuma
T
T
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002212:Capsicum; D002273:Carcinogens / Q000009:adverse effects*; D002338:Carotenoids / Q000031:analogs & derivatives* / Q000494:pharmacology; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D005260:Female; D008770:Methylnitrosourea / Q000009:adverse effects*; D010100:Oxygen; D010936:Plant Extracts; D010946:Plants, Medicinal; D051381:Rats; D011916:Rats, Inbred F344; D024341:Xanthophylls
D000975:Antioxidants; D002273:Carcinogens; D010936:Plant Extracts; D024341:Xanthophylls; D002338:Carotenoids; C006889:capsanthin; D008770:Methylnitrosourea; D010100:Oxygen