Flavonoids are widely distributed in the nature, and have various biological activities. Flavonoids can be degraded by intestinal bacteria, so as to impact their bioavailability in vivo. Studies on metabolism of flavonoids by intestinal bacteria could provide basis for screening out biotransformation of flavonoids and interpreting their in vivo metabolic process. Being taken as the lead compounds, flavonoids can be modified by intestinal bacteria to achieve new compounds with high efficiency, bioavailability and solubility, which lays a foundation for the research and development of new drugs, selection of drug dosage forms and drug production. This article summarizes the main reaction types and impacting factors of intestinal bacteria on biotransformation of flavonoids, for reference of studies on biotransformation.
Animals ; Bacteria ; metabolism ; Biotransformation ; genetics ; physiology ; Flavonoids ; metabolism ; Humans ; Intestines ; microbiology

Phytochemicals, orally administered substances, are found to undergo presystemic metabolism mainly in the intestine. Although early researches confirmed the role of intestinal bacteria in phytochemical presystemic metabolism, along with the development of molecular biology in investigating intestinal metabolism, a breakthrough has been won in research into metabolizing enzymes and transporters in intestine, which demands more attention and further studies. Recently, Cytochrome P450 3A has been found to be the most effective enzyme in mediating both oxidative (PhaseI) and conjugative (PhaseII) metabolism in the intestine. The present review summarizes the current findings correlated with the effect of intestinal cytochrome P450 3A on phytochemical presystemic metabolism, which provides a good basis for further research on phytochemical pharmacokinetics.
ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Animals ; Biotransformation ; physiology ; Cytochrome P-450 CYP3A ; physiology ; Drug Interactions ; physiology ; Drugs, Chinese Herbal ; metabolism ; Herb-Drug Interactions ; physiology ; Humans ; Intestines ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism

Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.
Base Pair Mismatch/drug effects ; Biotransformation/physiology ; Bone Substitutes/*toxicity ; Calcium Carbonate/*toxicity ; Chromosome Aberrations ; Escherichia coli/genetics ; Hydroxyapatites/*toxicity ; *Materials Testing ; *Mutagenicity Tests ; Salmonella typhimurium/genetics

In previous study we isolated a gram-positive bacterial strain, designated Niu-O16, from bovine rumen gastric juice. The growing cells of bacterial strain Niu-O16 is capable of biotransforming isoflavone daidzein into dihydrodaidzein efficiently under anaerobic conditions. In this study we investigated the optimal bioconversion conditions for the resting cells of bacterial strain Niu-O16 to convert daidzein into dihydrodaidzein. Single factor test showed that the optimal conditions for the initial pH of phosphate buffer, the concentration of the resting cell and the concentration of the substrate daidzein were 6.0-8.0, 32-64 mg/mL (wet weight) and 0.8-1.2 mmol/L, respectively. Orthogonal experiments were used to determine the optimal combination of the resting cell concentration, substrate concentration and biotransformation time. The results showed that the optimal combination included resting cell concentration 32 mg/mL, substrate concentration 0.8 mmol/L and the biotransformation time 24 h. Furthermore, the biotransformation kinetics under optimal conditions were studied, under which conditions the highest bioconversion rate was 63.9% in the resting cell system. The results might provide information for resting cell biotransforming of anaerobes as well as its industrial application.
Anaerobiosis ; Animals ; Biotransformation ; Cattle ; Culture Techniques ; methods ; Gastric Juice ; microbiology ; Gram-Positive Bacteria ; growth & development ; isolation & purification ; physiology ; Isoflavones ; biosynthesis ; chemistry ; metabolism ; Kinetics ; Rumen ; microbiology

Panax notoginseng saponins (PNS) are the major components of Panax notoginseng, with multiple pharmacological activities but poor oral bioavailability. PNS could be metabolized by gut microbiota in vitro, while the exact role of gut microbiota of PNS metabolism in vivo remains poorly understood. In this study, pseudo germ-free rat models were constructed by using broad-spectrum antibiotics to validate the gut microbiota-mediated transformation of PNS in vivo. Moreover, a high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was developed for quantitative analysis of four metabolites of PNS, including ginsenoside F1 (GF1), ginsenoside Rh2 (GRh2), ginsenoside compound K (GCK) and protopanaxatriol (PPT). The results showed that the four metabolites could be detected in the control rat plasma, while they could not be determined in pseudo germ-free rat plasma. The results implied that PNS could not be biotransformed effectively when gut microbiota was disrupted. In conclusion, gut microbiota plays an important role in biotransformation of PNS into metabolites in vivo.
Animals ; Anti-Bacterial Agents ; pharmacology ; Biotransformation ; Chromatography, High Pressure Liquid ; Feces ; microbiology ; Gastrointestinal Microbiome ; drug effects ; physiology ; Ginsenosides ; blood ; Male ; Panax notoginseng ; chemistry ; Rats, Sprague-Dawley ; Sapogenins ; blood ; Saponins ; administration & dosage ; metabolism ; Tandem Mass Spectrometry