Disposition and metabolism of dipropyl disulphide in vivo in rat

Abstract

The metabolism of dipropyl disulphide (DPDS), a sulphur compound from onion, was investigated in vivo in the rat. A single dose (200 mg kg⁻¹) was administered by gastric intubation and the time courses of DPDS and its metabolites were followed over 48 h by gas chromatography coupled with mass spectrometry in the stomach, intestine, liver, and blood. DPDS was detected in the stomach where it was transformed into propyl mercaptan, whereas the liver contained only traces of DPDS and none at all in the other examined organs. The metabolites methylpropyl sulphide, methylpropyl sulphoxide (MPSO), and methylpropyl sulphone (MPSO₂) were sequentially formed in the liver. The route of elimination from the liver seemed to be mainly via the blood. The bile also participated in the excretory process, but only for MPSO₂. The pharmacokinetic parameters were determined for all of the above compounds. Whereas the bioavailability of DPDS was very low (0.008 h mM), the areas under the curve were higher for the S-oxidized metabolites MPSO and MPSO₂, i.e. 9.64 and 24.15 h mM, respectively. The half-lives for DPDS and its metabolites varied between 2.0 and 8.25 h, except for MPSO₂, which had a half-life of 29.6 h. MPSO₂ was the most abundant and persistent of these metabolites.

Keywords :

• Allium
• onion
• metabolism
• dipropyl disulphide
• mercaptan
• sulphoxide
• sulphone