Sulfation Of 6-Gingerol By The Human Cytosolic Sulfotransferases

Objective: Previous studies have demonstrated the presence of sulfated form of 6-gingerol, a major pharmacologically-active component of ginger, in plasma samples of normal human subjects administered with 6-gingerol. The current study was designed to systematically identify the major human cytosolic sulfotransferase(SULT) enzyme(s) capable of mediating the sulfation of 6-gingerol. Here, we report a systematic analysis of the sulfating activity of the 13 known human SULTs towards 6-gingerol. The kinetic parameters of the sulfation of 6-gingerol by relevant SULTs were determined. The sulfation of 6-gingerol under metabolic conditions was investigated using cultured HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells. Cytosols of major human organs were also examined to verify the presence of 6-gingerol-sulfating activity in vivo. Moreover, to make sure the accurate chemical structure of sulfated-6-gingerol by Mass spectrometry analysis.Method: Thirteen human SULTs(SULT1A1, SULT1A2, SULT1A3, SULT1B1, SULT1C2, SULT1C3, SULT1C4, SULT1E1, SULT2A1, SULT2B1 a, SULT2B1 b, SULT4A1, SULT6B1), previously cloned, expressed, and purified, were analyzed for sulfating activity toward 6-Gingerol using an established sulfotransferase assay, as well as cytosols of human lung, liver, kidney, and small intestine. Kinetic parameters were determined by using different concentrations of 6-Gingerol. Cultured HepG2 and Caco-2 cells were labeled with [35S]sulfate in the presence of different concentrations of 6-Gingerol. Mass spectrometry was used to analysis the structure of sulfated-6-gingerol.Result: Of the 13 known human SULTs examined, six of them(SULT1A1, SULT1A2, SULT1A3, SULT1B1, SULT1C4, SULT1E1) displayed significant sulfating activity toward 6-gingerol. Kinetic parameters of four SULTs, SULT1A1, SULT1A3, SULT1C4 and SULT1E1 that showed stronger 6-gingerol-sulfating activity were determined. SULT1A1, the most important SULT enzyme to sulfate of 6-gingerol, was certificated. Of the four human organ samples tested, small intestine and liver cytosols displayed considerably higher 6-gingerol-sulfating activity than those of lung and kidney. Sulfation of 6-gingerol was shown to occur in HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells under the metabolic setting. Moreover, sulfated 6-gingerol was present in a mono-sulfated form and that the sulfated 6-gingerol was sulfated at its phenolic hydroxyl group.Conclusion: These results provided useful information relevant to the metabolism of 6-gingerol through sulfation both in vitro and in vivo.