title: Stability of [6]-gingerol and [6]-shogaol in simulated gastric and intestinal fluids.
abstract: The degradation kinetics of [6]-gingerol and [6]-shogaol were investigated in simulated gastric (pH 1) and intestinal (pH 7.4) fluids at 37 degrees C. Degradation products were quantitatively determined by HPLC (Lichrospher 60 RP select B column, 5 microm, 125 mm x 4 mm; mobile phase: methanol-water-acetic acid (60:39:1 v/v); flow rate: 0.6 ml/min; detection UV: 280 nm). In simulated gastric fluid (SGF) [6]-gingerol and [6]-shogaol underwent first-order reversible dehydration and hydration reactions to form [6]-shogaol and [6]-gingerol, respectively. The degradation was catalyzed by hydrogen ions and reached equilibrium at approximately 200 h. In simulated intestinal fluid (SIF) both [6]-gingerol and [6]-shogaol showed insignificant interconversion between one another. Addition of amino acids glycine, 3-amino propionic acid (beta-alanine) and gamma-amino butyric acid (GABA), and ammonium acetate at a range of concentrations of 0.05-0.5mM had no effect on the rate of degradation of [6]-shogaol in SGF and 0.1M HCl solution. However, at exceedingly high concentration (0.5M) of ammonium acetate and glycine, significant amounts of [6]-shogaol ammonia and glycine adducts were detected. The degradation profile of [6]-gingerol and [6]-shogaol under simulated physiological conditions reported in this study will provide insight into the stability of these compounds when administered orally.
authors: Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
authors: Sushila
authors: S
authors: Bhattarai
authors: Van H
authors: VH
authors: Tran
authors: Colin C
authors: CC
authors: Duke
mesh_terms: D001711:Biotransformation; D002396:Catechols / Q000737:chemistry* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D005233:Fatty Alcohols / Q000737:chemistry* / Q000493:pharmacokinetics; D005750:Gastric Juice / Q000737:chemistry / Q000378:metabolism; D020939:Zingiber officinale / Q000737:chemistry; D006801:Humans; D007419:Intestinal Secretions / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D012996:Solutions
chemical_list: D002396:Catechols; D005233:Fatty Alcohols; D010936:Plant Extracts; D012996:Solutions; C040115:shogaol; C007845:gingerol