title: Sweet Poisons: Honeys Contaminated with Glycosides of the Neurotoxin Tutin.
abstract: Poisonings due to consumption of honeys containing plant toxins have been reported widely. One cause is the neurotoxin tutin, an oxygenated sesquiterpene picrotoxane, traced back to honeybees (Apis mellifera) collecting honeydew produced by passionvine hoppers (Scolypopa australis) feeding on sap of the poisonous shrub tutu (Coriaria spp.). However, a pharmacokinetic study suggested that unidentified conjugates of tutin were also present in such honeys. We now report the discovery, using ion trap LC-MS, of two tutin glycosides and their purification and structure determination as 2-(β-d-glucopyranosyl)tutin (4) and 2-[6'-(α-d-glucopyranosyl)-β-d-glucopyranosyl]tutin (5). These compounds were used to develop a quantitative triple quadrupole LC-MS method for honey analysis, which showed the presence of tutin (3.6 ± 0.1 μg/g honey), hyenanchin (19.3 ± 0.5), tutin glycoside (4) (4.9 ± 0.4), and tutin diglycoside (5) (4.9 ± 0.1) in one toxic honey. The ratios of 4 and 5 to tutin varied widely in other tutin-containing honeys. The glycosidation of tutin may represent detoxification by one or both of the insects involved in the food chain from plant to honey.
authors.affiliation: †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Lesley
authors.initials: L
authors.lastname: Larsen
authors.affiliation: ‡The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch, New Zealand.
authors.forename: Nigel I
authors.initials: NI
authors.lastname: Joyce
authors.affiliation: †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Sansom
authors.affiliation: §The New Zealand Institute for Plant and Food Research Limited, Hamilton 3214, New Zealand.
authors.forename: Janine M
authors.initials: JM
authors.lastname: Cooney
authors.affiliation: §The New Zealand Institute for Plant and Food Research Limited, Hamilton 3214, New Zealand.
authors.forename: Dwayne J
authors.initials: DJ
authors.lastname: Jensen
authors.affiliation: †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Perry
mesh_terms: D005506:Food Contamination / Q000032:analysis; D006027:Glycosides / Q000032:analysis* / Q000737:chemistry / Q000506:poisoning; D006722:Honey / Q000032:analysis*; D015394:Molecular Structure; D009498:Neurotoxins / Q000097:blood / Q000493:pharmacokinetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D010852:Picrotoxin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D012717:Sesquiterpenes / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D006027:Glycosides; D009498:Neurotoxins; D010852:Picrotoxin; D012717:Sesquiterpenes; C009614:tutin