Pharmacological studies on ginger. I. Pharmacological actions of pungent constitutents, (6)-gingerol and (6)-shogaol.
General pharmacological studies were performed on (6)-gingerol and (6)-shogaol which are the pungent constituents of ginger (Zingiber officinale Roscoe). Intravenous (i.v.) administration of (6)-gingerol (at 1.75-3.5 mg/kg) or (6)-shogaol (at 1.75-3.5 mg/kg) and oral administration of them (at 70-140 mg/kg) produced an inhibition of spontaneous motor activity, an antipyretic and analgesic effects, prolonged hexobarbital-induced sleeping time, and these effects of (6)-shogaol were mostly more intensive than that of (6)-gingerol. (6)-Shogaol showed an intense antitussive effect in comparison with dihydrocodeine phosphate. In the electro-encephalogram of cortex, the low amplitude fast wave pattern was observed for 5 min after i.v. administration of (6)-shogaol, and then changed to the drowsy pattern, which was restored after 60 min. In the gastro-intestinal system, (6)-shogaol intensively inhibited the traverse of charcoal meal through the intestine in contrast with (6)-gingerol after i.v. administration of 3.5 mg/kg, but (6)-shogaol facilitated such an intestinal function after oral administration of 35 mg/kg. Both (6)-shogaol and (6)-gingerol suppressed gastric contraction in situ, and the suppression by the former was more intensive than that by the latter. In the cardiovascular system, both (6)-shogaol and (6)-gingerol produced depressor response at lower doses on the blood pressure. At high doses, both drugs produced three phase pattern.