title: Relaxant effects of quercetin methyl ether derivatives in isolated guinea pig trachea and their structure-activity relationships.
abstract: In the present study, we attempted to compare quercetin methyl ethers and to look for the structure-activity relationships, which may be helpful for synthesizing more active compounds for the treatment of asthma. Four present and two previously studied quercetin methyl ethers concentration-dependently relaxed histamine (30 microM), carbachol (0.2 microM) and KCl (30 mM) induced precontraction. According to their IC25 values to histamine-induced precontraction, the potency order was quercetin 3,3',4,'5,7-pentamethyl ether (QPME), quercetin 3-methyl ether > quercetin, quercetin 3,4',7-trimethyl ether (ayanin) > quercetin 4'-methyl ether (tamarixetin), quercetin 3,3',4',7,-tetramethyl ether (QTME). Therefore, the methylation at 3, at 5, and at both 3 and 7 positions of the A or/and C ring of quercetin nucleus may increase their tracheal relaxant activity. However, the methylation at the 3' and at the 4' position of the B ring of quercetin nucleus may decrease their tracheal relaxant activity.
authors.forename: W C
authors.initials: WC
authors.lastname: Ko
authors.forename: S W
authors.initials: SW
authors.lastname: Kuo
authors.forename: J R
authors.initials: JR
authors.lastname: Sheu
authors.forename: C H
authors.initials: CH
authors.lastname: Lin
authors.forename: S H
authors.initials: SH
authors.lastname: Tzeng
authors.forename: C M
authors.initials: CM
authors.lastname: Chen
mesh_terms: D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
chemical_list: D011794:Quercetin