title: Caffeic acid phenethyl ester (CAPE) analogues: potent nitric oxide inhibitors from the Netherlands propolis.
abstract: The MeOH and water extracts of the Netherlands propolis were tested for their inhibitory activity toward nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophage-like J774.1 cells. Both of the extract possessed significant NO inhibitory activity with IC(50) values of 23.8 and 51.5 microg/ml, respectively. Then 13 phenolic compounds obtained from the MeOH extract showing stronger NO inhibition were examined on their NO inhibitory activities. Caffeic acid phenethyl ester (CAPE) analogues, i.e., benzyl caffeate, CAPE and cinnamyl caffeate, possessed most potent NO inhibitory activities with IC(50) values of 13.8, 7.64 and 9.53 microM, respectively, which were two- to four-fold stronger than the positive control N(G)-monomethyl-L-arginine (L-NMMA; IC(50), 32.9 microM). Further study on the synthetic analogues of CAPE revealed that both of 3-phenylpropyl caffeate (18; IC(50), 7.34 microM) and 4-phenylbutyl caffeate (19; IC(50), 6.77 microM) possessed stronger NO inhibitory activity than CAPE (10) and that elongation of alkyl side chain of alcoholic parts of caffeic acid esters enhance the NO inhibitory activity. In addition, it was found that CAPE analogues having longer carbon chain (>C(5)) in alcoholic part showed toxic effects toward J774.1 cells. This NO inhibitory effect may directly correlate with antiinflammatory properties of the Netherlands propolis.
authors.affiliation: Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: Takema
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Arjun H
authors.initials: AH
authors.lastname: Banskota
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tezuka
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Midorikawa
authors.forename: Katsumichi
authors.initials: K
authors.lastname: Matsushige
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Kadota
mesh_terms: D000818:Animals; D002109:Caffeic Acids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009426:Netherlands; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D011429:Propolis / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: C000602374:3-phenylpropyl caffeate; D002109:Caffeic Acids; D009569:Nitric Oxide; D011429:Propolis; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol