title: Presence of calcium antagonist activity explains the use of Syzygium samarangense in diarrhoea.
abstract: Syzygium samarangense (Family; Myrtaceae) or 'makopa', as it is commonly known, is native to Malaysia, some islands of Indonesia and to Far East in general. This study was undertaken to rationalize the use of this plant in hypermotility states of the gut. The hexane extract of S. samarangense (Ss.Hex) was found to dose-dependently (10-3000 microg/mL) relax the spontaneously contracting isolated rabbit jejunum. When tested for a possible calcium channel blocking (CCB) activity, the extract (10-1000 microg/mL) relaxed the high K+-induced contractions and also decreased the Ca++ dose-response curves in a dose-dependent manner (30-100 microg/mL), confirming the CCB activity. Four flavonoids isolated from the hexane extract were tested for a possible spasmolytic activity. All flavonoids, identified as: 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (SS1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (SS2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (SS3) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (SS4), showed dose-dependent (10-1000 microg/mL) spasmolytic activity with SS2 being the most potent. These results indicate that the presence of compounds with spasmolytic and calcium antagonist activity may be responsible for the medicinal use of the plant in diarrhoea.
authors.affiliation: Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi 74800, Pakistan.
authors.forename: M N
authors.initials: MN
authors.lastname: Ghayur
authors.forename: A H
authors.initials: AH
authors.lastname: Gilani
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: E C
authors.initials: EC
authors.lastname: Amor
authors.forename: I M
authors.initials: IM
authors.lastname: Villaseñor
authors.forename: M I
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D003967:Diarrhea / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D018515:Plant Leaves / Q000737:chemistry; D011817:Rabbits; D027842:Syzygium / Q000737:chemistry*
chemical_list: D002121:Calcium Channel Blockers; D010936:Plant Extracts