ABSTRACT
ObjectiveTo study the metabolism of chemical components from Citri Reticulatae Pericarpium（CRP）in different parts of rats by sequential metabolism and ultra performance liquid chromatography-high resolution mass spectrometry（UPLC-HRMS）. MethodSD male rats were employed as experimental subjects， and blood samples of intestinal metabolism and hepatic metabolism were prepared after administration of CRP ethanol extract by in situ intestinal perfusion， and comprehensive metabolic samples were collected after intragastric administration. UPLC-HRMS was used to analyze the samples with acetonitrile（A）-0.1% formic acid aqueous solution（B）as the mobile phase for gradient elution（0-10 min， 10%-30%A； 10-30 min， 30%-95%A； 30-31 min， 95%-10%A； 31-35 min， 10%A）at a flow rate of 0.35 mL·min-1， using a heated electrospray ionization with positive and negative ion mode scanning in the range of m/z 100-1 500. Under these conditions， the differences in the profiles of CRP ethanol extract， blank plasma and drug-containing plasma under different treatment groups were compared， and the chemical components of each sample were analyzed and identified based on the retention time， accurate relative molecular mass， primary and secondary ion fragments， and the information of reference substances. ResultA total of 44 chemical components were identified in the CRP ethanol extract， including flavone-O-glycosides， flavone-C-glycosides and polymethoxyflavonoids， etc. The results of sequential metabolism showed that 22 chemical components in CRP were detected in the intestinal metabolic sample， 18 chemical components were detected in the hepatic metabolic sample， and 9 identical chemical components（narirutin， hesperidin， meranzin， 5，7，8，3ʹ，4ʹ，5ʹ-hexamethoxy-flavone， isosinensetin， sinensetin， 3，5，6，7，8，3ʹ，4ʹ-heptamethoxyflavone， nobiletin and tangeretin）could be detected in all three metabolic samples， with a total of 22 compounds entering the blood in prototype form. ConclusionThe identified 21 components with well-defined structures entering the blood as prototypes may be potential active components of CRP， and differences in the components at different metabolic parts can provide an experimental basis for elucidating the in vivo biotransformation process of the metabolic components of CRP.
ABSTRACT
Flavonoid glycosides (FGs) are secondary metabolites of many plants widely found in nature, and exhibit significant biological activities, such as anticancer, antioxidant and antimicrobial. According to the glycosidic bonds, FGs are divided into flavonoid O-glycosides and flavonoid C-glycosides. The main metabolic processes of FGs in vivo were specific hydrolysis in the gastrointestinal tract and glucuronidation in liver. Glucose, xylose, rhamnose and other glycosyl groups were hydrolyzed to produce secondary glycosides or aglycones in the gastrointestinal tract that were absorbed into blood, and then further glucuronidation and methylation metabolites are mainly produced by phase II metabolism in liver. This article reviews the metabolism in vivo and biotransformation in vitro of some typical natural flavonoid glycosides exited in Chinese materia medica (CMMs), such as flavonoid O-glycosides in Epimedii Folium, Glycyrrhizae Radix et Rhizoma, Scutellariae Radix, Citri Reticulatae Pericarpium, and Cirsii Japonici Herba, and flavonoid C-glycosides in Anemarrhenae Rhizoma and Puerariae Lobatae Radix. The investigation of the metabolisms of FGs in vivo is helpful for the clarification of the effective ingredients in CMMs, which will provide the basis for new drugs development based on metabolites in vivo.
ABSTRACT
Objective: In order to obtain new glycosyltransferases with highly efficient catalysis, the glycosyltransferases from Carthamus tinctorius which contains diverse types of glycosides were mined. Methods: A new glycosyltransferase gene (UGT88B2) with full length was obtained by PCR and further transformed into Escherichia coli for heterologous expression. The catalytic activity of recombinant UGT88B2 was determined by HPLC-MSn. The structures of representative catalytic products were elucidated by MS and NMR. Results: UGT88B2 exhibited catalytic promiscuity and various patterns in glycosylation of flavonoids with high efficiency. Conclusion: A new glycosyltransferase named UGT88B2 was successfully mined and can be employed as enzymatic tools in glycosylation of flavonoids.
ABSTRACT
The aim of this study was to look for the chemical constituents from the rhizomes of Dryopteris sublaeta. The fresh plant was extracted twice with boiling water, the extract was concentrated to small volume under reduced pressure at 50 ℃. The concentrated material was partitioned with ether, ethyl acetate and n-butanol. The fraction of ethyl acetate was repeatedly chromatographied over silica gel and Sephadex LH-20 columns. Structures of pure compounds were established on the basis of their physiochemical and spectral data. Nine compounds were obtained and identified as sublaetentin A (1), sublaetentin B (2), sublaetentin C (3), sublaetentin D (4), matteuorienate A (5), matteuorienate C (6), arbutin (7), 3-methoxy-4-hydroxyphenyl-1-O-β-D-glucopyranoside (8) and 3,4-dimethoxyphenyl-1-O-β-D-glucopyranoside (9). Compounds 1-4 are new compounds, the others were isolated from this plant for the first time.