| Co-Investigator(Kenkyū-buntansha) |
FUJIKI Hirota National Cancer Center Research, Cancer Prevention Division, Head, がん予防研究部長, 部長 (60124426)
YAZAKI Kazufumi Okayama University, Faculty of Pharmaceutical Sciences, Instructor, 薬学部, 助手 (00191099)
HATANO Tsutomu Okayama University, Faculty of Pharmaceutical Sciences, Instructor, 薬学部, 助手 (50127578)
MORI Kazuko Okayama University, Faculty of Pharmaceutical Sciences, Instructor, 薬学部, 助手 (20032823)
YOSHIDA Takashi Okayama University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (20025696)
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| Research Abstract |
In a search of anti-tumor promoter in nature, over a hundred polyphenolic compounds have been isolated from medicinal plants of various origin. Each species of these plants mostly provided upon this investigation several new polyphenolic compounds, accompanied by other compounds. These plants include species of Artemisia, Bredia, Camellia, Cornus, Corylus, Davidia, Euphorbia, Geranium, Glycyrrhiza, Melastoma, Oenothera, Phyllanihus, Platycarya, Psidium, Rosa, Trapa, Woodfordia and others.
Some hydrolyzable tannin oligomers among these polyphenols were found to have unique macro-ring structures, and several polyphenols of large molecule showed host-mediated anti-tumor activity.
Upon the experiments of inhibition of tumor promotion induced with teleocidin on mouse skin, pentagalloylglucose and (-)- epigallocatechin gallate (EGCG) markedly inhibited this tumor promotion. Oral administration of EGCG, the main polyphenolic component in green tea, was also found to inhibit strongly tumor promotion in the gastrointestinal tract in a model system of mouse duodenal carcinogenesis with ENNG.
Inhibition of active oxygen, which can be regarded as correlated with tumor promotion, was significantly inhibited by several polyphenolic compounds isolated from plants in the present study. Evidence for the mechanism, of this inhibition which is attributable to their radical-scavenging activity, was obtained.
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