Development of Fecal Microbial Enzyme Mix for Mutagenicity Assay of Natural Products

Abstract

Orally administered herbal glycosides are metabolized to their hydrophobic compounds by intestinal microflora in the intestine of animals and human, not liver enzymes, and absorbed from the intestine to the blood. Of these metabolites, some, such as quercetin and kaempherol, are mutagenic. The fecal bacterial enzyme fraction (fecalase) of human or animals has been used for measuring the mutagenicity of dietary glycosides. However, the fecalase activity between individuals is significantly different and its preparation is laborious and odious. Therefore, we developed a fecal microbial enzyme mix (FM) usable in the Ames test to remediate the fluctuated reaction system activating natural glycosides to mutagens. We selected, cultured, and mixed 4 bacteria highly producing glycosidase activities based on a cell-free extract of feces (fecalase) from 100 healthy Korean volunteers. When the mutagenicities of rutin and methanol extract of the flos of Sophora japonica L. (SFME), of which the major constituent is rutin, towards Salmonella typhimurium strains TA 98, 100, 102, 1,535, and 1,537 were tested using FM and/or S9 mix, these agents were potently mutagenic. These mutagenicities using FM were not significantly different compared with those using Korean fecalase. SFME and rutin were potently mutagenic in the test when these were treated with fecalase or FM in the presence of S9 mix, followed by those treated with S9 mix alone and those with fecalase or FM. Freeze-dried FM was more stable in storage than fecalase. Based on these findings, FM could be usable instead of human fecalase in the Ames test.

Ophiopogon Polysaccharide Promotes the In Vitro Metabolism of Ophiopogonins by Human Gut Microbiota

“…is one of the most important gut bacteria that releasing all of the four glycosidases selected in the present study, e.g., β-D-glucosidase [35], β-D-xylosidase [36], α-L-rhamnosidase [37] and β-D-fucosidase [38]. Significant difference of the glycosidase activities were observed among the four glycosidases (i.e., β-D-glucosidase > β-D-xylosidase > β-D-fucosidase > α-L-rhamnosidase), these results were consistent with previous studies, and the differences were probably caused by the composition of gut microbiota [19,39,40]. Ophiopogon polysaccharide has been reported to possess modulation effects on gut microbiota, i.e., promoting the growth of some probiotics (e.g., Bifidobacterium and Lactobacillus ) and inhibiting the accumulation of pathogenic bacteria (e.g., Escherichia and Desulfovibrionaceae ) [15,16,17].…”

Gut Reactions: Breaking Down Xenobiotic–Microbiome Interactions

“…This has been applied in the study of lovastatin (Yoo et al, 2014) and amlodipine (Yoo et al, 2016) and to look at the effect of probiotics on the pharmacokinetics of acetaminophen (Kim et al, 2018). Concerns about the variability of the assay have seen the development of a fecal microbial enzyme mix (Yeo et al, 2012). Haiser et al (2014) have outlined how these approaches might be combined in a framework for studying microbial drug metabolism that includes functional metagenomics to gain mechanistic insights and bioinformatics to guide rational microbiome-targeted therapeutic interventions.…”

A New Approach to Produce Resveratrol by Enzymatic Bioconversion

“…Great efforts have been made to explore new resveratrol-containing plants, construct genetically modified resveratrol-producing plants and microorganisms, and cultivate plant tissue or cells [4,13,20]. Comparatively, enzymatic biosynthesis should be a desirable approach because of its high efficiency, mild reaction conditions, and independence from cell growth [17,24]. However, enzymatic biosynthesis of resveratrol has not yet been reported.…”