[Induction of NAD(P)H: quinone reductase by anticarcinogenic ingredients of tea].
By assaying the activity of NAD(P)H: quinone reductase (QR) in Hep G2 cells exposed to inducing agents, a variety of ingredients in tea, we compared their abilities on inducing QR and preventing cancer. The results showed that tea polyphenols, tea pigments and mixed tea were all able to induce the activity of QR significantly. The single-component ingredients of tea polyphenols and tea pigments, including thearubigens, EGCG and ECG, also enhanced the activity of QR. But EGC, EC, theaflavins, tea polysaccharide and tea caffeine, showed no apparent induction of QR. We found that among those tea ingredients studied, the multi-component ingredients were more effective than the single-component ones. So we thought that the abilities of antioxidation and cancer prevention of tea depended on the combined effects of several kinds of active ingredients, which mainly include tea polyphenols and tea pigments.
Qi
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Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, Beijing 100050, China.
Han
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C
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D005419:Flavonoids; D008113:Liver Neoplasms / Q000473:pathology*; D051379:Mice; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology*; D010860:Pigments, Biological / Q000302:isolation & purification / Q000494:pharmacology; D011108:Polymers / Q000302:isolation & purification / Q000494:pharmacology*; D059808:Polyphenols; D013662:Tea / Q000737:chemistry*; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D005419:Flavonoids; D010636:Phenols; D010860:Pigments, Biological; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D016660:NAD(P)H Dehydrogenase (Quinone)