OBJECTIVETo study the transport mechanism of honokiol in Caco-2 cell model.

METHODThe analysis was performed on a Kromasil 100-5 C18 column (4.5 mm x 250 mm, 5 microm) eluted with acetonitrile-water (70: 30) as mobile phase. The detection wavelength was set at 203 nm. Two-way transport of honokiol was studied by using Caco-2 cell model, and the effects of time, drug concentration, inhibitor, pH, temperature on the transport of honokiol was investigated. The drug concentrations were determined by high performance liquid chromatography(HPLC) and used to calculate the apparent permeability coefficient.

RESULTThe standard curve of honokiol was Y = 24 044X - 3 763.6 (r = 0.999 8), and the detection limit was 0.04 micromol x L(-1). In Caco-2 cell model, the transport amounts from the top side to the base side of were more than that from the base side to the top side under the same concentration. The transport amounts increased with time both in AP --> BL and BL --> AP directions. Verapamil could improve the transport amounts of AP --> BL. There were no effects of pH on the transport of AP --> BL. Both in AP --> BL and BL --> AP directions, the transport showed temperature dependence.

CONCLUSIONHonokiol is transported through the intestinal mucosa via a passive diffusion mechanism primarily, coexisting with a carrier-mediated transport, at the same time effected by P-gp.