title: Spasmolytic flavonoids from Syzygium samarangense (Blume) Merr. & L.M. Perry.
abstract: The hexane extract of Syzygium samarangense (Ss.Hex) dose-dependently (10-1000 microg/ ml) relaxed the spontaneously contracting isolated rabbit jejunum. Four rare C-methylated flavonoids with a chalcone and a flavanone skeleton were isolated from Ss.Hex and were subsequently tested for spasmolytic activity. All flavonoids, identified as 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (3), and 7-hydroxy-5-methoxy-6,8-dimethyl-flavanone (4), showed dose-dependent spasmolytic activity in the rabbit jejunum with IC50 values of 148.3 +/- 69.4, 77.2 +/- 43.5, 142.4 +/- 58.6 and 178.5 +/- 37.5 microg/ml (mean +/- SEM), respectively. The dihydrochalcone derivative of compound 1, 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (5), when tested for spasmolytic activity, did not significantly relax the smooth muscle relative to the other compounds. Verapamil, a standard spasmolytic, has an IC50 value of 0.16 +/- 0.04 microg/ml. This is the first report of the relaxant activity of chalcones, specifically of compounds 1-3.
authors.affiliation: Institute of Chemistry, College of Science, University of the Philippines, Diliman 1101, Quezon City, Philippines. evangeline.amor@up.edu.ph
authors.forename: Evangeline C
authors.initials: EC
authors.lastname: Amor
authors.forename: Irene M
authors.initials: IM
authors.lastname: Villaseñor
authors.forename: M Nabeel
authors.initials: MN
authors.lastname: Ghayur
authors.forename: Anwar H
authors.initials: AH
authors.lastname: Gilani
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D000818:Animals; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D066298:In Vitro Techniques; D007583:Jejunum / Q000187:drug effects / Q000502:physiology*; D008958:Models, Molecular; D008968:Molecular Conformation; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D027822:Myrtaceae / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011817:Rabbits; D013329:Structure-Activity Relationship
chemical_list: D005419:Flavonoids; D010936:Plant Extracts