title: Relationship between antibacterial activity of (+)-catechin derivatives and their interaction with a model membrane.
abstract: (+)-Catechin derivatives with different alkyl chain lengths were synthesized from (+)-catechin and various straight chain alkylaldehydes in the presence of methyl mercaptan, and their antibacterial activities against Gram-positive bacteria were evaluated. The antibacterial activity increased markedly with elongation of the alkyl chain lengths of the derivatives and reached a maximum at a chain of four to seven carbons. Subsequently, interaction of the (+)-catechin derivatives with a model membrane using liposome was investigated. The derivatives with a chain of three carbons or more were found to have very strong affinity for the membrane. The injury action of the derivatives against the membrane was examined with liposome in which calcein was enclosed as a fluorescent indicator. The leakage was observed in the derivatives with chain lengths of four carbons or more. Particularly the derivatives with chains longer than five carbons are considered to destroy the liposome membrane judging from the degree of the fluorescent leakage. These results implied that the lipophilicity and disrupting ability of the (+)-catechin derivatives to the liposome membrane participate in their antibacterial activity.
authors.affiliation: Laboratory of Functional Food Science and COE Program in the 21st Century, Department of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
authors.forename: Katsuko
authors.initials: K
authors.lastname: Kajiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hojo
authors.forename: Masayuki
authors.initials: M
authors.lastname: Suzuki
authors.forename: Fumio
authors.initials: F
authors.lastname: Nanjo
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kumazawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D006094:Gram-Positive Bacteria / Q000187:drug effects; D008081:Liposomes / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D008081:Liposomes; D002392:Catechin