title: Biosynthesis of cyanohydrin glucosides from unnatural nitriles in intact tissue of Passiflora morifolia and Turnera angustifolia.
abstract: Passiflora morifolia, which under natural conditions contains cyanohydrin glucosides linamarin, lotaustralin and epilotaustralin, converted cyclopentanecarbonitrile, 2-cyclopentenecarbonitrile and 3-methylbutanenitrile into the corresponding cyanohydrin glucosides. Turnera angustifolia, which normally produces glucosides of cyclopentenone cyanohydrin, converted cyclopentanecarbonitrile, 2-methylpropanenitrile and 2-methylbutanenitrile, but not 3-methylbutanenitrile, into the corresponding cyanohydrin glucosides. Mixtures of epimers were produced when these glucosides contained chiral cyanohydrin carbon atoms. Feeding with cyclopentanecarbonitrile resulted in formation of 1-(beta-D-glucopyranosyloxy)cyclopentanecarbonitrile, a saturated analogue of deidaclin and tetraphyllin A. Neither plant utilized cyclopropanecarbonitrile as substrate. The experiments demonstrate broad substrate specificity of nitrile hydroxylases present in these plants. A novel glycoside, 2-[6-O-(beta-D-xylopyranosyl)-beta-D-glucopyranosyloxy]propane (isopropyl primeveroside), was isolated from P. morifolia. The compound represents a rare example of natural isopropyl glycoside; its characterization included assignment of all 1H and 13C NMR signals of the primeverosyl group using two-dimensional NMR methods. Biosynthesis of the isopropyl moiety of the primeveroside is unclear, but the formation of alcohols corresponding to natural cyanohydrins may be a previously unrecognized extension of the cyanohydrin biosynthesis pathway in higher plants.
authors.affiliation: Department of Medicinal Chemistry, Royal Danish School of Pharmacy, Copenhagen, Denmark.
authors.forename: J W
authors.initials: JW
authors.lastname: Jaroszewski
authors.forename: A B
authors.initials: AB
authors.lastname: Rasmussen
authors.forename: H B
authors.initials: HB
authors.lastname: Rasmussen
authors.forename: C E
authors.initials: CE
authors.lastname: Olsen
authors.forename: L B
authors.initials: LB
authors.lastname: Jørgensen
mesh_terms: D001711:Biotransformation; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005960:Glucosides / Q000096:biosynthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009570:Nitriles / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D005960:Glucosides; D009570:Nitriles