Protective activity of hamamelitannin on cell damage induced by superoxide anion radicals in murine dermal fibroblasts.
Previously we demonstrated that hamamelitannin (2',5-di-O-galloyl hamamelose) in Hamamelis virginiana L. exhibits potent superoxide-anion scavenging activity. We then examined the physiological and pharmacological activities of hamamelitannin as well as its functional homologues, gallic acid and syringic acid. The following results were obtained: (1) Hamamelitannin has a higher protective activity against cell damages induced by superoxide anions than gallic acid which is the functional moiety of hamamelitannin. The protective activity of hamamelitannin on murine fibroblast-damage induced by superoxide anions was found at a minimum concentration of 50 microM, while the corresponding figure for gallic acid was 100 microM. (2) Pre-treatment of fibroblasts with hamamelitannin enhances cell survival. (3) The superoxide-anion scavenging activity of the compound in terms of its IC50 value (50% inhibition concentration of superoxide anion radicals generated) was evaluated by ESR spin-trapping. Both hamamelitannin (IC50 = 1.31 +/- 0.06 microM) and gallic acid (IC50 = 1.01 +/- 0.03 microM) exhibited high superoxide-anion scavenging activity followed by syringic acid (IC50 = 13.90 +/- 2.38 microM). (4) When hamamelitannin was treated with superoxide anions generated by a KO2-crown ether system, HPLC analysis showed the disappearance of hamamelitannin and the concomitant formation of hamamelitannin-derived radicals (g = 2.005, delta H1 = 2.16 G, delta H2 = 4.69 G) was detected by ESR spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)
Masaki
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H
Shiga Central Laboratory, Noevir Co., Ltd., Youkaichi, Japan.
Atsumi
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T
Sakurai
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H
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D005419:Flavonoids; D016166:Free Radical Scavengers; D005707:Gallic Acid / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D010636:Phenols / Q000737:chemistry / Q000633:toxicity; D010936:Plant Extracts / Q000494:pharmacology; D010944:Plants / Q000737:chemistry; D011108:Polymers / Q000737:chemistry / Q000633:toxicity; D059808:Polyphenols; D012867:Skin / Q000166:cytology / Q000187:drug effects; D013481:Superoxides / Q000037:antagonists & inhibitors* / Q000633:toxicity
D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D011108:Polymers; D059808:Polyphenols; D013481:Superoxides; D005707:Gallic Acid