1999 Fiscal Year Final Research Report Summary
Inhibitory effects of apple pectin on experimental hepatic metastasis and portal free radical
| Project/Area Number |
10671106
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General surgery
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| Research Institution | Toyama Medical and Pharmaceutical University |
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Principal Investigator |
TAZAWA Kenji Faculty of Medicine, Toyama Medical and Pharmaceutical University Professor, 医学部, 教授 (80018887)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEMORI Shigeru Hospital, Toyama Medical and Pharmaceutical University Assistant Professor, 附属病院, 講師 (30227061)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Apple pectin / superoxide anion / hydroxyl radical / oligosaccharide / Fenton reaction / Azoxymethane / dietary fiber / free radical |
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| Research Abstract |
Among the various kinds of pectin, apple pectin exerts a bacteriostatic action and therefore may change the composition of the intestinal flora. We examined here, the inhibitory effects of apple pectin in colon carcinogenesis using water-soluble methoxylated pectin from apples. Supplementation of the diet with 20% apple pectin significantly decreased the number and incidence of Azoxymethane-induced colonic tumors. Prostaglandin E2 levels in distal colonic mucosa or portal blood from 20% apple pectin fed rats were lower than those in basal diet fed rats. Furthermore, 20 % apple pectin fed rats demonstrated a significantly reduced incidence of experimental portal bacteremia induced by methotrexate. The incidence of hepatic metastasis was significantly reduced with a 20% apple pectin diet.
We investigated the action of apple pectin on anticarcinogenesis focusing on the antioxidant activity evaluated by an electron spin trapping technique (ESR) in which the superoxide anion radicals and hyd
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roxyl radicals were generated by hypoxanthin-xanthin oxidase (HPX-XOD) and ferrous sulfate-hydrogen peroxide (Fenton reaction systems), respectively. Apple pectin is a partially methoxylated polymer of galacturonic acid obtained from apple. In the apple pectic oligosaccharide-containing assay system, trapping-signals for both radicals became significantly lower compared with phosphate buffered saline-containing one, indicating that apple pectic oligosaccharide actually exhibited scavenging activity. When apple pectic oligosaccharide was divided into five fractions based on the degree of polymerization, a fraction with a lower polymerization (pos-S) showed a stronger scavenging activity than those with a higher one. Moreover, this activity was enhanced after heating of pos-S (121℃ for 30min ).
In conclusion, apple pectin may exert an antitumor effect and prevent cancer metastasis and portal bacteremia by modifying the hosts immune function and/or by altering the intestinal flora. Dietary fibers such as pectin have an important function in the intestinal tract as anti-inflammatory materials. The effect of apple pectin supplementation on anti-metastatic action was evaluated. Pectic oligosaccharides with small molecular weights showed highly inhibitory effects on HPX-XOD and Fenton reaction systems. The scavenging activity of pectic oligosaccharide was suitable and accelerated at high temperatures. Apple pectin has a scavenger effect in the intestinal digestion and portal circulation system as an anti-inflammatory food. Dietary fibers like pectin have very important function in intestinal tract as ant-inflammatory foods. Less
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