| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Shoko Okayama University, Fac.Pharm.Sci., Res.Assoc., 薬学部, 助手 (20243488)
ITO Hideyuki Okayama University, Fac.Pharm.Sci., Res.Assoc., 薬学部, 助手 (70253002)
HATANO Tsutomu Okayama University, Fac.Pharm.Sci., Assoc.Prof., 薬学部, 助教授 (50127578)
HIRAI Yoshikazu Jichi Med.University, Medical School, Professor, 医学部, 教授 (00127581)
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| Research Abstract |
Based on the fact that polyphenolics such as green tea catechins and polyphenols in cocoa are known to show anti-Helicobacter pylori (HP) activity, polyphenolic components of various species of Leguminosae, Geraniaceae, Euphorbiaceae, Betulaceae and Iridaceae were examined in order to discover effective anti-HP agents. This study led to the isolation of 27 new antioxidative polyphenolics, which include flavonoids, hydrolysable tannin monomers and oligomers, and 7 new iridal-type triterpenoids with piscicidal activity. Their structures were elucidated on the basis of spectral and chemical evidence. Among these compounds, hydrolysable tannins exhibited potent anti-HP activity with MIC 3.13〜12.5μg/ml, whereas procyanidins and EGCG had MIC 12.5〜100μg/ml. The most potent anti-HP activity was exhibited by tellimagrandin I, corilagin and strictinin. This activity was bactericidal, but not statistical. These active polyphenols were not sensitive to ordinary pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, Batilus subtilis and Pseudomonus aeruginosa, indicating their specific action to HP.Tellimagrandin I and corilagin were also found to have synergestic action with β-lactam on methicillin-resistant Staphylococcus aureus (MRSA). The MIC of oxacillin against MRSA was reduced to 1/100〜1/500 upon addition of these tannins (50μg/ml), suggesting a promising strategy to overcome the MRSA.
In addition, the hydrolyzable tannins showed inhibitory effects on histamine-release from rat mast cells, which was induced by superoxide anion and/or compound 48/80.
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