Effects of blackcurrant extract on indole and ammonia productions in an in vitro human fecal culture model.

Blackcurrant is available as a traditional medicine in Europe. However, the detailed effects of blackcurrant on the human gut microbiota remain unknown. In this study, we investigated the prebiotic effects of a blackcurrant extract using a human fecal culture model in six healthy subjects. Feces were individually inoculated into a medium with or without the blackcurrant extract and then fermented for 48 hr under anaerobic conditions. The results obtained from analysis of samples from the fermented medium demonstrated that after 48 hr of fermentation, the pH of the medium with the blackcurrant extract was significantly decreased (control, 6.62 ± 0.20; blackcurrant extract, 6.41 ± 0.33; p=0.0312). A 16S rRNA gene sequencing analysis of the microbiota of the fermented medium showed a significant increase in the relative abundance of Bifidobacteriaceae. In measuring the concentrations of putrefactive components in the fermented medium, we found that the blackcurrant extract significantly reduced ammonia levels and displayed a tendency toward reduced indole levels. Our results suggest that blackcurrant extract could be a potential ingredient for relief of putrefactive components in the gut.

Inhibitory effect of trans-tiliroside on very low-density lipoprotein secretion in HepG2 cells and mouse liver.

An acylated flavonol glycoside, trans-tiliroside (1), is found in certain parts of different herbs, including the seeds of Rosa canina (Rosaceae). Previous studies on compound 1 have focused on triglyceride (TG) metabolism, including its anti-obesity and intracellular TG reduction effects. In the present study, the effects of compound 1 on cholesterol (CHO) metabolism were investigated using human hepatocellular carcinoma-derived HepG2 cells and mice. Compound 1 decreased CHO secretion in HepG2 cells, which was enhanced by mevalonate in a concentration-dependent manner and decreased the secretion of apoprotein B (apoB)-100, a marker of very low-density lipoprotein (VLDL). Compound 1 also inhibited the activity of microsomal triglyceride transfer proteins, which mediate VLDL formation from cholesterol and triglycerides in the liver. In vivo, compound 1 inhibited the accumulation of Triton WR-1339-induced TG in the blood of fasted mice and maintained low levels of apoB-100. These results suggest that compound 1 inhibits the secretion of CHO as VLDL from the liver and has the potential for use for the prevention of dyslipidemia.

Effect of a Bifidobacterium-Containing Acid-Resistant Microcapsule Formulation on Gut Microbiota: A Pilot Study.

Approximately 10 Bifidobacterium species are known to inhabit the human intestinal tract. Bifidobacteria have been reported to possess a variety of probiotic benefits. However, when bifidobacteria are consumed internally as probiotics, the bacteria are killed by gastric acid. Therefore, we developed acid-resistant microcapsules containing Bifidobacterium breve M-16V and B. longum BB536, which are unaffected by gastric acid, and evaluated whether the microcapsule formulation increased the amount of bifidobacteria in the stool after administration compared with the powder formulation. The results revealed no significant difference in the percentage or number of B. longum between before and after administration of the powder or microcapsule formulation in children. By contrast, the bacterial count of B. breve was significantly increased after microcapsule formulation administration (1.5 × 105 copies/g after administration versus 2.8 × 104 copies/g before administration, p = 0.013). In addition, the increase in the bacterial count of B. breve in stools after administration of microcapsule formulation was approximately 1000-fold higher than that after powder formulation administration (p = 0.018). In conclusion, the results indicate that the microcapsule formulation is efficiently transferred to the large intestine without the adverse effects of gastric acidity in children.