title: Bioassay-guided fractionation of lemon balm (Melissa officinalis L.) using an in vitro measure of GABA transaminase activity.
abstract: A novel pharmacological mechanism of action for the anxiolytic botanical Melissa officinalis L. (lemon balm) is reported. The methanol extract was identified as a potent in vitro inhibitor of rat brain GABA transaminase (GABA-T), an enzyme target in the therapy of anxiety, epilepsy and related neurological disorders. Bioassay-guided fractionation led to the identification and isolation of rosmarinic acid (RA) and the triterpenoids, ursolic acid (UA) and oleanolic acid (OA) as active principles. Phytochemical characterization of the crude extract determined RA as the major compound responsible for activity (40% inhibition at 100 microg/mL) since it represented approximately 1.5% of the dry mass of the leaves. Synergistic effects may also play a role.
authors.affiliation: Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Rosalie
authors.initials: R
authors.lastname: Awad
authors.forename: Asim
authors.initials: A
authors.lastname: Muhammad
authors.forename: Tony
authors.initials: T
authors.lastname: Durst
authors.forename: Vance L
authors.initials: VL
authors.lastname: Trudeau
authors.forename: John T
authors.initials: JT
authors.lastname: Arnason
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors*; D000818:Animals; D002934:Cinnamates / Q000302:isolation & purification / Q000494:pharmacology*; D053630:Depsides / Q000302:isolation & purification / Q000494:pharmacology*; D031334:Melissa / Q000737:chemistry*; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D014315:Triterpenes / Q000302:isolation & purification / Q000494:pharmacology; D000097123:Rosmarinic Acid; D000097245:Ursolic Acid
chemical_list: D000612:4-Aminobutyrate Transaminase; D002934:Cinnamates; D053630:Depsides; D009828:Oleanolic Acid; D010936:Plant Extracts; D014315:Triterpenes; D000097123:Rosmarinic Acid; D000097245:Ursolic Acid