Biotransformation of naringin by human intestinal flora

Naringin （1）, the highest-content flavanone glycoside in sour oranges, was incubated with human intestinal flora, and four biotransforrnation products （2-5） were obtained from the incubated mixture by chromatographic methods. The chemical structures of the four products were elucidated as naringin-6＂acetate （2）, naringenin （3）, phloretic acid （4）, and phloroglucinol （5） on the basis of their spectroscopic data. Naringin-6＂-acetate was specifically formed by acetylation at C6-OH of glucosyl group of 1. The result obtained in the present research could account for the lower bioavailability of 1 after oral administration, suggesting that some biological properties of 1 in vivo may be mediated by its intestinal flora converted product 3. The biotransforrnation of 1 by intestinal flora leading to their systemic absorption deserves further attention and may provide valuable insights into pre-systemic drug metabolism, delivery or toxicity.

Transformation of trollioside and isoquercetin by human intestinal flora in vitro

The present study was designed to determine the intestinal bacterial metabolites of trollioside and isoquercetin and their antibacterial activities. A systematic in vitro biotransformation investigation on trollioside and isoquercetin, including metabolite identification, metabolic pathway deduction, and time course, was accomplished using a human intestinal bacterial model. The metabolites were analyzed and identified by HPLC and HPLC-MS. The antibacterial activities of trollioside, isoquercetin, and their metabolites were evaluated using the broth microdilution method with berberine as a positive control, and their potency was measured as minimal inhibitory concentration(MIC). Our results indicated that trollioside and isoquercetin were metabolized by human intestinal flora through O-deglycosylation, yielding aglycones proglobeflowery acid and quercetin, respectively The antibacterial activities of both metabolites were more potent than that of their parent compounds. In conclusion, trollioside and isoquercetin are totally and rapidly transformed by human intestinal bacteria in vitro and the transformation favors the improvement of the antibacterial activities of the parent compounds.

Anti-mutagenicity of Swertiamarin and Its Metabolite in Incubated System of Human Intestinal Flora

Objective To study the biotransformation regulation and pharmacological effect of swertiamarin and its metabolite in incubated system of human intestinal flora. Methods Incubated system of human intestinal flora was utilized to research the intestinal metabolism of swertiamarin. Furthermore, mutagenic test and anti-mutagenic test were carried out to research the activity relationship of swertiamarin and its metabolite. Results Gentianine was found in the metabolites of swertiamarin. The pharmacological experiment indicated that swertiamarin and its metabolite both had good anti-mutagenic effect. Conclusion Swertiamarin is partly metabolized to gentianine after oral administration. They show similar anti-mutagenicity effects.

UFLC-DAD-ESI-IT-TOFMSn Analysis on Biotransformation of Tongmai Formula Incubated with Human Intestinal Bacteria

Objective To investigate the biotransformation of Tongmai formula（TMF） in incubated system of human intestinal flora（HIF）. Methods The technique of ultra fast liquid chromatography with diode array detector and coupled with electrospray ionization ion trap time-of-flight multistage mass spectrometry（UFLC-DAD-ESIIT-TOFMSn） was adopted to determine the products of TMF biotransformed by HIF. Results Totally 66 constituents were detected and identified according to the accurate mass measurements（〈 5 ppm） and effective MSn fragment ions. Meanwhile, the potential biotransformational pathways of compounds in TMF transformed by HIF were firstly proposed. Desugarization, hydroxylation, and methylation were the major reactions in the biotransformation mechanism of TMF by HIF. Conclusion This study will be helpful to clarify the material basis of pharmacological activities from TMF in vivo.