title: Structural elucidation of a tadalafil analogue found as an adulterant of a herbal product.
abstract: A tadalafil analogue and hydroxyhomosildenafil were isolated from a herbal product marketed for erectile dysfunction. The structure of the tadalafil analogue was elucidated using LC-UV, high resolution MS, ESI-MS/MS, IR, and NMR. The compound was determined to be (6R,12aR)-2-amino-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6] pyrido[3,4-b]indole-1,4-dione. This compound should be included as a target compound when screening for adulterants in herbal products. This is the first published paper on a tadalafil analogue and hydroxyhomosildenafil found as adulterants of a herbal product.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Science Drive 4, Singapore 117543.
authors.forename: Peng
authors.initials: P
authors.lastname: Zou
authors.forename: Peiling
authors.initials: P
authors.lastname: Hou
authors.forename: Min-Yong
authors.initials: MY
authors.lastname: Low
authors.forename: Hwee-Ling
authors.initials: HL
authors.lastname: Koh
mesh_terms: D002243:Carbolines / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D019587:Dietary Supplements / Q000032:analysis*; D007172:Erectile Dysfunction / Q000178:diet therapy; D005506:Food Contamination; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D000068581:Tadalafil
chemical_list: C513595:(6R,12aR)-2-amino-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydropyrazino(1',2'-1,6)pyrido(3,4-b)indole-1,4-dione; D002243:Carbolines; D010726:Phosphodiesterase Inhibitors; D010936:Plant Extracts; D000068581:Tadalafil