title: Rare excitatory amino acid from flowers of zonal geranium responsible for paralyzing the Japanese beetle.
abstract: The Japanese beetle (JB), Popillia japonica, exhibits rapid paralysis after consuming flower petals of zonal geranium, Pelargonium x hortorum. Activity-guided fractionations were conducted with polar flower petal extracts from P. x hortorum cv. Nittany Lion Red, which led to the isolation of a paralysis-inducing compound. High-resolution-MS and NMR ((1)H, (13)C, COSY, heteronuclear sequential quantum correlation, heteronuclear multiple bond correlation) analysis identified the paralytic compound as quisqualic acid (C(5)H(7)N(3)O(5)), a known but rare agonist of excitatory amino acid receptors. Optical rotation measurements and chiral HPLC analysis determined an L-configuration. Geranium-derived and synthetic L-quisqualic acid demonstrated the same positive paralytic dose-response. Isolation of a neurotoxic, excitatory amino acid from zonal geranium establishes the phytochemical basis for induced paralysis of the JB, which had remained uncharacterized since the phenomenon was first described in 1920.
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Application Technology Research Unit, Wooster, OH 44691, USA. christopher.ranger@ars.usda.gov
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Ranger
authors.forename: Rudolph E
authors.initials: RE
authors.lastname: Winter
authors.forename: Ajay P
authors.initials: AP
authors.lastname: Singh
authors.forename: Michael E
authors.initials: ME
authors.lastname: Reding
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Frantz
authors.forename: James C
authors.initials: JC
authors.lastname: Locke
authors.forename: Charles R
authors.initials: CR
authors.lastname: Krause
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D001517:Coleoptera / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000737:chemistry / Q000633:toxicity; D018846:Excitatory Amino Acids / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D035264:Flowers / Q000737:chemistry*; D031315:Geranium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D016318:Quisqualic Acid / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D013237:Stereoisomerism
chemical_list: D018690:Excitatory Amino Acid Agonists; D018846:Excitatory Amino Acids; D016318:Quisqualic Acid