Plasma pharmacokinetics and tissue distribution of [6]-gingerol in rats.
[6]-Gingerol is one of the pungent components in ginger which has been found to possess various pharmacological effects. However, there is insufficient information on the properties of [6]-gingerol based on controlled pharmacokinetic studies. The aim of this study was to clarify distribution profiles of [6]-gingerol in blood and biological tissues of experimental rats. Rats were administered a 240 mg/kg dose of Gs (a ginger extract, containing 53% [6]-gingerol) by oral ingestion. Plasma samples were collected at 2.5, 5, 7.5, 10, 15, 20, 30, 45 min, and 1, 1.5, 2, 3, 4 h after dosing (eight samples per time point), and brain, heart, lung, spleen, liver, kidney, stomach and small intestine tissues were collected at 5, 15, 30 min and 1, 2, 4 h after dosing (five animals per time point). Samples were prepared by a liquid-liquid extraction procedure and the extracts were assayed by HPLC-UV. After per oral application, [6]-gingerol was absorbed rapidly into the plasma, and the maximal concentration (4.23 microg/ml) was reached after 10 min post dosing. [6]-Gingerol plasma concentrations declined with time in a biexponential pattern. The elimination half-time at the terminal phase was 1.77 h and the apparent total body clearance was 40.8 l/h. When administered orally, [6]-gingerol was well distributed to the tissues examined, with the highest concentrations found in the gastrointestinal tract. Maximal concentrations of [6]-gingerol were reached in most tissues at 0.5 h post-dosing. The concentrations of [6]-gingerol in tissues all were higher than in plasma with corresponding tissue to plasma ratios greater than 1 after 0.25 h post-dose, showing high tissue partitioning and extensive distribution.