title: Biological activity of ellagitannins: Effects as anti-oxidants, pro-oxidants and metal chelators.
abstract: Ellagitannins are a subclass of hydrolysable tannins that have been suggested to function as defensive compounds of plants against herbivores. However, it is known that the conditions in the digestive tracts of different herbivores are variable, so it seems reasonable to anticipate that the reactivities and modes of actions of these ingested defensive compounds would also be different. A previous study on a few ellagitannins has shown that these polyphenolic compounds are highly oxidizable at high pH and that their bioactivity can be attributed to certain structural features. Herein, the activities of 13 ellagitannins using the deoxyribose assay were measured. The results provided information about the anti-oxidant, pro-oxidant and metal chelating properties of ellagitannins. Surprisingly, many of the tested ellagitannins exhibited pro-oxidant activities even at neutral pH and only moderate to low radical scavenging activities, although the metal chelating capacities of all tested ellagitannins were relatively high.
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland. Electronic address: johanna.m.moilanen@gmail.com.
authors.forename: Johanna
authors.initials: J
authors.lastname: Moilanen
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: Maarit
authors.initials: M
authors.lastname: Karonen
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: Petri
authors.initials: P
authors.lastname: Tähtinen
authors.affiliation: Université de Bordeaux, Institut des Sciences Moléculaires (CNRS-UMR 5255), Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac Cedex, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Jacquet
authors.affiliation: Université de Bordeaux, Institut des Sciences Moléculaires (CNRS-UMR 5255), Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac Cedex, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Quideau
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Salminen
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000378:metabolism*; D016877:Oxidants / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D000975:Antioxidants; D047348:Hydrolyzable Tannins; D016877:Oxidants; D017382:Reactive Oxygen Species
keywords: Anti-oxidation; Deoxyribose assay; Hydrolysable tannins; Metal ion chelation; Pro-oxidation; Radical scavenging