gingerol and Hypothermia

The aim of this study is to enhance the antihypothermic action of ginger extract (GE) employing a solid dispersion (SD) approach. The prepared SD of GE (GE/SD) was characterized in terms of physicochemical and pharmacokinetic properties. The antihypothermic action of GE samples was evaluated in a rat model of hypothermia. GE/SD exhibited improved dissolution behavior of the major active ingredients in GE, 6-gingerol (6G) and 8-gingerol (8G), with levels of dissolution 12- and 31-fold higher than that of GE, respectively. Even after storage under accelerated conditions, limited degradations of 6G and 8G were observed in GE/SD, although 6G and 8G were slightly degraded in GE. After oral administration of GE (300 mg/kg) and GE/SD (100 mg of GE/kg), the relative bioavailabilities of 6G and 8G in GE/SD were 5.0- and 5.8-fold higher than those in GE, respectively. Orally administered GE/SD (30 mg of GE/kg) inhibited ethanol-evoked hypothermia because of improved oral absorption of 6G and 8G. From these observations, the SD approach might be efficacious for enhancing the nutraceutical potentials of GE.

Topics: Animals; Biological Availability; Body Temperature; Catechols; Chemistry, Pharmaceutical; Drug Stability; Fatty Alcohols; Humans; Hypothermia; Male; Plant Extracts; Rats; Solubility; Zingiber officinale

We investigated the effects of systemic administrations of ginger (Zingiber officinale Roscoe, Zingiberaceae) or its pungent constituent, [6]-gingerol, on resting body temperature in rats. Rats given ginger-containing rat chow for 5 days showed no changes in their day-night cycle of body temperature or physical activity. However, a single intraperitoneal (i.p.) injection of [6]-gingerol (2.5 or 25 mg/kg) induced a rapid, marked drop in body temperature in a dose-related manner, with no change in physical activity. A significant decrease in metabolic rate was observed immediately after an i.p. injection of [6]-gingerol (25 mg/kg), although heat-loss responses underwent no alteration (versus vehicle). These results suggest that in rats: (a) a decrease in metabolic rate is responsible for the [6]-gingerol-induced hypothermia, and (b) [6]-gingerol modulates or interferes with the mechanisms underlying body temperature regulation, while other bioactive constituents of ginger may counteract the hypothermic effect of [6]-gingerol.

Topics: Administration, Oral; Animals; Basal Metabolism; Body Temperature; Body Temperature Regulation; Catechols; Circadian Rhythm; Dose-Response Relationship, Drug; Fatty Alcohols; Hypothermia; Injections, Intraperitoneal; Male; Motor Activity; Rats; Rats, Wistar; Thermogenesis; Zingiber officinale

One of the important medicinal properties of ginger is known to remove chills caused by common cold and to warm body. In the present study, acetone extract of ginger at 100 mg/kg p.o. significantly inhibited serotonin (5-HT) induced hypothermia. Therefore, the active constituents of ginger were further examined. The acetone extract was functioned into 4 fractions by column chromatography. Fractions 1 and 2 showed significant activity. Fraction 2 was further purified and [6]-shogaol which was obtained from fraction 2-2, at 10 mg/kg p.o. was shown to inhibit 5-HT induced hypothermia. Anticathartic activity is known to be one of the medicinal effects of ginger. In the present study, acetone extract of ginger at 75 mg/kg p.o., significantly inhibited 5-HT induced diarrhea. In order to clarify the active constituents, the acetone extract was fractionated into 4 fractions by silica gel chromatography. Fractions 2 and 3, which was especially effective, were further purified and [6]-shogoal, [6]-dehydrogingerdione, [8]- and [10]-gingerol were found to have an anticathartic action. [6]-Shogaol was more potent than [6]-dehydrogingerdione, [8]- and [10]-gingerol.

Topics: Acetone; Animals; Catechols; Diarrhea; Fatty Alcohols; Hypothermia; Ketanserin; Mice; Pindolol; Plant Extracts; Plants, Medicinal; Serotonin