Yokukansan, a Herbal Medicine in Japan, Buffers Social Crowding Stress via Ameliorating Glucocorticoid Secretion Response to Vasopressin.

On the basis of the data that yokukansan (YKS), a herbal medicine, ameliorates aggressive behavior and abnormal glucocorticoid secretion of socially isolated mice under zinc deficiency, we tested whether YKS preventively buffers crowding stress-induced attenuations of glucocorticoid secretion response and long-term potentiation (LTP), an index of cognition. YKS-containing water was administered during the period of exposure to social crowding stress for 3 weeks. Serum corticosterone level was not significantly modified by administration of YKS-containing water and was also not increased after social-crowding stress. When vasopressin was injected into crowding-stressed rats to assess corticosterone secretion via pituitary-adorenocortical axis activation, vasopressin-induced increase in serum corticosterone was significantly attenuated compared to non-stressed control rats, indicating that the pituitary-adrenocortical response to vasopressin is affected after exposure to crowding stress. Interestingly, administration of YKS-containing water rescued attenuation of vasopressin-induced increase in serum corticosterone. LTP at Schaffer collateral-CA1 pyramidal cells synapses was attenuated in the hippocampal slices from crowding-stressed rats, while administration of YKS-containing water rescued the attenuation. The present study demonstrates that intake of YKS rescues crowding stress-induced impairments of glucocorticoid secretion response to vasopressin and hippocampal LTP. The intake of YKS may be benefit to buffering chronic stress.

Protective effects of tranilast on experimental colitis in rats.

The present study aimed to verify the efficacy of tranilast (TL) for treating inflammatory bowel disease (IBD) with the use of an experimental colitis model. The experimental colitis model was prepared by intrarectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS; 40mg/kg) dissolved in water containing 25% ethanol. The pharmacological effects of TL after repeated oral administration were evaluated by biomarker and histological analyses, and the pharmacokinetic behavior of TL was also examined after single oral administration. The intrarectal instillation of TNBS solution caused colitis, as evidenced by ca. 2.2-, 5-, and 3-fold increases in myeloperoxidase (MPO) activity, infiltrated cell numbers, and the thickness of the submucosa in the colon, respectively. However, orally-taken TL (10mg/kg, twice a day for 9days) led to a 92% reduction in the increase of the MPO level by TNBS enema, and cellular infiltration and thickened submucosa in the experimental colitis model tended to also be suppressed by repeated oral administration of TL. The oral bioavailability of TL in TNBS-treated rats was calculated to be as low as ca. 6.5%, and the poor oral absorption of TL may be a limitation of the treatment for IBD. TL could attenuate TNBS-induced colitis on the basis of the obtained results, and the anti-inflammatory effects would have clinical relevance to the therapeutic outcomes of TL in IBD patients. Although further improvement in the oral bioavailability of TL might be required for better pharmacological outcomes, TL would be an efficacious agent for treating IBD.

Ginger Extract-Loaded Solid Dispersion System with Enhanced Oral Absorption and Antihypothermic Action.

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.