Toshiki Okubo

Antianxiety-like effects of Chimpi (dried citrus peels) in the elevated open-platform test.

Dried citrus peels (Chimpi) is one of the most common natural medicines with qi (energy flow) rectifying and shi (dampness) drying actions, which originates from Citrus unshiu, and/or C. reticulata according to the definition of the pharmacopoeiae of Japan and China. In this study, the pharmacological effects of their extracts and major chemical constituents hesperidin and its aglycone hesperetin on anxiety were examined with an anxiety model of elevated open-platform test using ICR male mice (6-week-old) and total duration of freezing was decreased in fluoxetine-treated mice, which is a simple and highly sensitive to the effects of serotonergic anxiolytics. Moreover, yokukansankachimpihange (YKH), a combination of yokukansan with Chimpi and Hange (Pinellia) was also examined because Chimpi is considered to play a crucial part in this formula against anxious symptoms in dementia patients. The results showed that Chimpi and YKH possess a significant anxiolytic-like effect similar to that of fluoxetine, suggesting that they might be similar to fluoxetine in their pharmacological actions through the serotonergic neurotransmission pathway. Moreover, it also suggested that the major chemical constituent, hesperidin could be an active principle attributed to the antianxiety-like effects with a direct and indirect role via its aglycone hesperetin.

A Kampo formula, saikokaryukotsuboreito, improves serum testosterone levels of castrated mice and its possible mechanism

Abstract The term “late-onset hypogonadism (LOH)” is recommended to express the symptoms in middle-aged males with decreased testosterone. Although androgen replacement therapy (ART) might be an effective way to manage LOH, the risk of testosterone supplementation in elderly men is still concerned. On the other hand, to avoid adverse effects of ART, Kampo medicine (traditional Chinese–Japanese medicine) is often a first choice to treat LOH in Japan. However, their pharmacological studies are few. In this study, castrated mice was used as an LOH animal model for examining the pharmacological effects of a Kampo formula, saikokaryukotsuboreito (shortly SKRBT) on serum testosterone levels and seminal vesicles weights. Furthermore, an attempt to elucidate its pharmacological mechanism, inhibition of SKRBT and its components against aromatase were also examined with the enzyme-based assay. As a result, SKRBT improved significantly both the decline of serum testosterone levels and decrease of seminal vesicles weight of castrated mice at a dose of 125 mg/kg with a non dose-dependent manner. SKRBT and two components Scutellariae radix and Rhei rhizoma exhibited inhibitory activities with the IC50 values of 145, 29.2 and 29.7 µg/ml, respectively. These results suggested that the aromatase inhibitory activity of SKRBT may contribute, to a different extent, to the improvement of serum testosterone levels.