Anxiolytic-like effect of Shigyakusan extract with low side effects in mice.

Shigyakusan is a traditional Japanese herbal (Kampo) medicine used to treat inflammatory conditions such as cholecystitis and gastritis as well as psychiatric disorders. This study examined the anxiolytic-like effect of Shigyakusan extract (SS), and evaluated the activity of the main compound. Three behavioral tests in mice were used to evaluate the activity of SS. Samples were administered orally over a 10-day period. A light and dark box (LDB) test was performed on the 8th day, while an open field (OF) test was done on the 9th day, and an elevated plus maze (EPM) test was performed on the 10th day. Diazepam (DZ), a typical anxiolytic drug, was used as the positive control. Administration of 10 mg/kg DZ resulted in a significant anxiolytic-like effect in the LDB and EPM tests, while administration of 0.3 g/kg SS resulted in a weak anxiolytic-like effect. In the OF test, while DZ caused a significant reduction of locomotor activity, SS did not cause any changes compared to the water controls. This suggests that locomotor activity may be a side effect of DZ, and thus SS, which lacks this response, may be a more useful treatment. Quantitative analysis performed to clarify the activity of the main compound also determined that SS contained 51.4 mg/g naringin, which also has been reported to have anxiolytic-like activity. Since these results suggested that this compound might be responsible for the activity of SS, we subsequently examined the oral administration of a similar dose of naringin. Although we observed a tendency for a weak anxiolytic-like effect, this effect was not greater than that seen for SS.

Production and accumulation of xylooligosaccharides with long chains by growing culture and xylanase of a mutant strain of Bacillus pumilus X-6-19.

Bacillus pumilus X-6-9 isolated from soil and subsequently identified, produced xylooligosaccharides with long chains from xylan and accumulated them in the culture. By improving the culture conditions and mutating the bacterium, a 3.2-fold increase in the production of the xylooligosaccharides was established, when compared to the original culture conditions of B. pumilus X-6-19. The addition of D-glucose to the culture of the mutant strain U-3 of B. pumilus X-6-9 repressed the synthesis of beta-xylosidase, but not xylanase. Thus, it was revealed that strain U-3 was a good organism for the production and accumulation of xylooligosaccharides with long chains from xylan by a microbial culture. Xylanase produced by strain U-3 was purified to homogeneity and characterized. The hydrolyzates generated by the purified xylanase contained xylobiose, xylotriose, xylotetraose, and xylopentaose, but not xylose.

The suppressive effects of dietary protein restriction on the progression of renal impairment in OLETF rats.

BACKGROUND: The suppressive effect of dietary protein restriction on the progression of diabetic nephropathy remains controversial. We investigated the effects of protein and energy restrictions on both albuminuria and morphology using diabetic-prone Otsuka Long-Evans Tokushima fatty (OLETF) rats. METHODS: In this study, male OLETF rats were divided into two groups according to their energy intake. They were then further divided into three subgroups based on their amount of dietary protein, which ranged between 10% and 30% of their total intake. Urinary albumin excretion (UAE) was used as a marker of renal impairment, and body weight fasting (F) and postchallenge (P), blood glucose (BG) levels, and systolic blood pressure (SBP) were all measured during various experimental periods up to 28 weeks of age. RESULTS: The OLETF rats fed with the high-calorie diet started to gain weight at 12 weeks, and their FBG and PBG were elevated at 22 weeks, while SBP did not differ between the two groups. In addition, UAE increased significantly in the rats fed with the high-calorie diet. However, the increasing rates of UAE with age were higher in the rats with a higher protein diet within the same energy groups. UAE correlated well with the amounts of dietary energy and protein at 16 and 28 weeks of age, while it correlated with both the FBG and PBG at only 28 weeks of age. A linear regression analysis, using the data obtained at 28 weeks, showed that the amount of protein intake and FBG explained 63.4% and 23.9% of the variation in UAE, respectively. Histological studies revealed that protein and energy restriction markedly reduced the sclerotic changes of the glomeruli. CONCLUSION: Dietary protein restriction starting very early in the life of OLETF rats, in combination with energy restriction, clearly suppressed UAE and the typical morphological changes that otherwise occurred at around 16 weeks of age. This method also seemed to be more effective than energy restriction alone in slowing down any increase in UAE. The influence of BG levels on UAE was lower at an early age, while it became an increasingly important factor at later ages in the experimental rat model.