Preparation of a Major Metabolite of Iguratimod and Simultaneous Assay of Iguratimod and Its Metabolite by HPLC in Rat Plasma.

Iguratimod is a new synthetic disease-modifying antirheumatic drug intended to treat patients with rheumatoid arthritis. A new method using recombinant human CYP450s yeast cells containing c-DNA expressed P450s was applied to identify the metabolic pathways of iguratimod and to prepare its metabolite. The metabolite was isolated, and its structure was identified by quadrupole time-of-flight-mass spectrometry and nuclear magnetic resonance. Furthermore, a selective and sensitive high performance liquid chromatography (HPLC) method was developed for the simultaneous quantification of iguratimod and its major metabolite in rat plasma for the first time. The results indicated that iguratimod was mainly metabolized to a metabolite by CYP2C9 and CYP2C19 in in-vitro study. The structure of the metabolite was identified as M2 (N-[3-(acetamido)-4-oxo-6-phenoxy-4H-chromen-7-yl]methanesulfonamide). HPLC assay was achieved on a C18 column using methanol-water containing 0.1% trifluoroacetic acid (55:45 v/v) at a flow rate of 1 mL/min with UV detection at 257 nm. Standard calibration curves were obtained in the concentration range of 0.5-20 µg/mL for iguratimod and its metabolite M2. The lower limits of detection of iguratimod and M2 in rat plasma were 0.1 and 0.25 µg/mL, respectively. The intra- and inter-day precision (RSD%) were within 5% for the two analytes. The average recoveries of the analytes were greater than 90%. In conclusion, recombinant human CYP450s whole-yeast transformation system could be successfully used to identify and prepare the major metabolite of iguratimod. The HPLC method we developed could be successfully applied to evaluate pharmacokinetics of iguratimod and its metabolite M2 in rats.

Research progress on chemical constituents and pharmacological effects of Glechomae Herba and prediction of its Q-markers / 中国中药杂志

Glechomae Herba, the dried aerial part of Glechoma longituba(Labiatae), has the effects of promoting urination, draining dampness, and relieving stranguria. It has received wide attention in recent years owing to the satisfactory efficacy on lithiasis. Amid the in-depth chemical and pharmacological research, it has been found that Glechomae Herba has antibacterial, anti-inflammatory, antioxidant, antithrombotic, hepatoprotective, cholagogic, antitumor, hypoglycemic, and lipid-lowering effects. The main chemical constituents are volatile oils, flavonoids, terpenoids, phenylpropanoids, and organic acids. This paper summarized the chemical constituents and pharmacological effects of Glechomae Herba. Based on genetic relationship of plants, the characteristics, efficacy, and pharmacokinetics of the chemical constituents, and the potential of these constituents as quality markers(Q-markers), it was summed up that ursolic acid, caffeic acid, rosmarinic acid, luteolin-7-O-diglucuronide, apigenin, apigenin-7-O-diglucuronide, apigetrin, and glechone can be the candidate Q-markers of Glechomae Herba.

Characteristic identification of Sophorae Flavescentis Radix and Sophorae Tonkinensis Radix et Rhizoma based on HPTLC-ESI-MS / 药学学报

Sophorae Flavescentis Radix is the dried root of Sophora flavescens Ait. and Sophorae Tonkinensis Radix et Rhizoma is the dried root and rhizome of Sophora tonkinensis Gagnep. The two drugs are both from the same genus Sophora, having similar and different compositions and efficacies, however, their differences are not fully demonstrated in current standard. In this study, the high-performance thin-layer chromatography with multi-dimensional and multi-level features combined with electric spray mass spectrometry (HPTLC-ESI-MS) was used to discover and identify the characteristic zones in extracts of Sophorae Flavescentis Radix and Sophorae Tonkinensis Radix et Rhizoma, after optimizing the preparation method of the test solution and chromatographic parameters. As a result, 17 main characteristic zones were found on HPTLC chromatograms of Sophorae Flavescentis Radix and Sophorae Tonkinensis Radix et Rhizoma, among them, besides 3 known chemicals, another 12 unknown components were identified by HPTLC-ESI-MS, they are 1 alkaloid and 11 flavonoids. The identification results were verified by the reference standards partially and nuclear magnetic resonance spectra after guided-isolation. Finally, a unified HPTLC specific identification method with different markers was established to identify Sophorae Flavescentis Radix and Sophorae Tonkinensis Radix et Rhizoma simultaneously. Thanks to abundant chemical information provided when using diverse polarity mobile phases and derivatization reagents, the HPTLC technology offers a convenient strategy for discovery, quality evaluation, and identification of target chemicals when connecting with mass spectrometry.

Chemical constituents from hypoglycemic active part of Plantaginis Semen / 中国中药杂志

The chemical constituents of Plantaginis Semen with hypoglycemic effect was investigated in this paper. The previous results of the in vivo hypoglycemic effect showed that 60% ethanol extract of Plantaginis Semen decreased the levels of FBG and improved the glucose tolerance in high fat diet(HFD)-induced diabetic C57BL/6 mice. Then, in the present study, the above potential bioactive extract was separated and purified by silica gel, ODS, Sephadex LH-20 column chromatography, medium pressure liquid chromatography(MPLC)and preparative HPLC. The structures of isolated compounds were identified by physicochemical properties and spectral analyses. Eight compounds were obtained and identified as 4, 4a, 5, 7a-tetrahydro-7-(hydroxymethyl)cyclopenta[c]pyran-3(1H)-one(1), iridolactone(2), pedicularislacton(3), rehmaglutin C(4), geniposidic acid(5), p-hydroxylphenylglycerol(6), 1, 2-benzenediol-4-(2-hydroxyethyl)(7), and 3-buten-2-one-4-[3-(β-D-glucopyranosyloxy)-4-hydroxyphenyl](8). Among them, compounds 1-5 were iridoids, and 6-8 were phenolic acids. Compound 1 was a new natural product, and compounds 2-4, 6 and 8 were isolated from the Plantaginaceae family for the first time.