title: Structure elucidation of sildenafil analogues in herbal products.
abstract: The structure of unknown compounds present in herbal products was elucidated using liquid chromatography-electrospray ionization-mass spectrometry, direct-infusion electrospray ionization-mass spectrometry, and nuclear magnetic resonance. Compounds 1-3 were identified as sildenafil analogues, 1 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine, and an acetyl group instead of the sulfonyl group, named acetildenafil, 2 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine (homosildenafil), and 3 bearing an N-hydroxylethylpiperazine moiety instead of an N-methylpiperazine, named hydroxyhomosildenafil. When analysing products marketed for penile erectile dysfunction or marketed as aphrodisiacs, attention should be given to the possible presence of these components.
authors.affiliation: Centre for Quality of Chemical-Pharmaceutical Products, National Institute for Public Health and the Environment, PO Box 1, NL-3720 BA Bilthoven, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Blok-Tip
authors.forename: B
authors.initials: B
authors.lastname: Zomer
authors.forename: F
authors.initials: F
authors.lastname: Bakker
authors.forename: K D
authors.initials: KD
authors.lastname: Hartog
authors.forename: M
authors.initials: M
authors.lastname: Hamzink
authors.forename: J
authors.initials: J
authors.lastname: Ten Hove
authors.forename: M
authors.initials: M
authors.lastname: Vredenbregt
authors.forename: D
authors.initials: D
authors.lastname: De Kaste
mesh_terms: D002243:Carbolines / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods; D007093:Imidazoles / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry*; D028321:Plant Preparations / Q000737:chemistry*; D011687:Purines; D000068677:Sildenafil Citrate; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013450:Sulfones; D000068581:Tadalafil; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D014665:Vasodilator Agents / Q000737:chemistry*
chemical_list: D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D028321:Plant Preparations; D011687:Purines; D013450:Sulfones; D014227:Triazines; D014665:Vasodilator Agents; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate