Latest ArticlesL-Proline-m-bis (2-chloroethyl) amino-L-phenylalanyl-L-norvaline ethyl ester hydrochloride (MF13) is a new anticancer tripeptide. Our previous study in vitro and in vivo showed that MF13 had anti-proliferative activities in a panel of human hepatocellular carcinoma (HCC) cell lines from different origin. In the present study, we focused on the inhibition effect on HCC of MF13 combined with other anti-cancer drugs. The results of combination chemotherapy in vitro indicated that the combination of MF13 with mitomycin C (MMC) at appropriate concentrations led to a synergistic effect; however, the combination of MF13 with vincristine (VCR) showed no synergistic effect. In the Bel-7402 tumor bearing nude mice, the antitumor effect of the groups of 2 mg·kg-1 MF13 + 2 mg·kg-1 MMC or 2 mg·kg-1 MF13 + 50 mg·kg-1 cyclophosphamide (CTX) exhibited synergistic anticancer efficacies while the group of 2 mg·kg-1 MF13 + 0.3 mg·kg-1 VCR did not have the same effect. Based on our data, we believe that MF13 can be considered as a potential agent against human hepatocellular carcinoma no matter how treated, alone or combined with other drugs.
IG-105, N-(2, 6-dimethoxypyridine-3-yl)-9-methylcarbazole-3-sulfonamide, a novel antimicrotubule agent, showed potent anticancer activity in a variety of human tumor cells in vitro and in vivo. In order to characterize the metabolism and the possible drug-drug interaction of IG-105, we carried out a series of experiments. Drug metabolizing enzymes involved in IG-105 metabolism were investigated by using pooled human liver microsomes (HLMs) and recombinant cytochrome P450 isoforms (rP450s) respectively. The possible metabolites were analyzed by liquid chromatography-orbitrap-mass spectrometry (LC-Orbitrap-MS). The inhibitory effect of IG-105 on main P450 enzymes was also evaluated. The results showed that IG-105 can be metabolized by a series of rP450s, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5, with the major contribution enzymes being CYP1A2, CYP2B6, CYP2C19, and CYP3A. Three metabolites (M1-M3) were identified and demethylation was the major phase I metabolic reaction for IG-105. IG-105 moderately inhibited CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A enzyme activities with IC50 values of 6.42, 23.64, 0.39, 1.4, and 3.14 μmol·L-1, respectively. Since the biotransformation of IG-105 involves multiple enzymatic pathways, the compound is less likely to be a victim of a concomitantly used medicine which inhibits activity of one of the CYPs. However, as IG-105 showed medium to strong inhibition on CYP1A2, CYP2D6, CYP3A, and CYP2C19, caution is particularly needed when IG-105 is co-administrated with other anticancer drugs which are mainly metabolized by the above enzymes.
Studies have shown that acetylcholinesterase inhibitors donepezil and galantamine have effects of reducing neuronal damage caused by glucose deprivation and reducing the cerebral infarction volume of cerebral ischemic animals, but their effects may not be entirely dependent on its inhibition of cholinesterase activity. In order to study the effects of donepezil and galantamine on neuronal injury of cerebral ischemia, the rat neuron-astrocyte co-culture model was successfully established in this study. In this model, we studied the effects of donepezil and galantamine on neuron apoptosis induced by oxygen-glucose deprivation/reoxygenation (OGD/R) and investigated the mechanism. The results showed that donepezil and galantamine significantly reduced the neuron apoptosis, and promoted the synthesis and secretion of BDNF and NGF in astrocytes in the co-culture system. Donepezil and galantamine activated the PI3K/Akt pathway and ERK pathway, and promoted the phosphorylation of the nuclear transcription factor CREB. These results suggest that donepezil and galantamine exhibit protective effects on neuronal damage induced by OGD/R. The mechanism may be related to activation of PI3K/Akt pathway and ERK pathway in astrocytes and promote phosphorylation of CREB, which lead to the synthesis and secretion of BDNF and NGF from astrocytes.
Cathepsin K (CTSK) is considered a critical pharmaceutical target in the treatment of osteoporosis. CTSK exerts proteolytic activities against regulatory proteins besides its collagenase function, which may account for some of the adverse reactions when blocked by active site-directed inhibitors. Exosite inhibitors that can discriminate between the therapeutic collagenase and other biological activities of CTSK specifically inhibit the collagenase activity of CTSK without interfering with the other proteolytic activities of the protease. Active recombinant CTSK was expressed in Pichia pastoris, and purified by n-butyl sepharose and SP sepharose column chromatography. Herba Ecliptae is a common traditional Chinese medicine in the treatment of bone diseases. Collagenase assay and benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin (Z-FR-MCA) substrate assay based on CTSK are applied to verify the exosite inhibitors. n-Butanol extract of Herba Ecliptae are the most active fraction and eclalbasaponin Ⅸ isolated from n-butanol fraction is the potential exosite inhibitor of CTSK.
This study was designed to investigate the chemical constituents of the anti-osteoporotic part of Lepidium meyenii Walp. (maca) produced in Heqing, Yunnan. Seven compounds were isolated from the n-BuOH extract of maca using combination of column chromatographies on MCI resin, silica gel, C18 bonded silica gel, and Sephadex LH-20, followed by semi-preparative HPLC and recrystallization. The purified compounds were identified on the basis of their physicochemical properties and spectral data as macaolidine (1), tryptophan (2), daucosterol (3), (3S)-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylicacid (4), chlorogenic acid (5), luteolin (6), and hyperoside (7). Compound 1 is a new phenylacetamide alkaloid, and compounds 4-7 were isolated from Lepidium meyenii for the first time.
Two flavanone glucosides were isolated from the 80% ethanol extract of Glycyrrhiza uralensis using various chromatographic techniques, including macroporous adsorbent resin, RP-C18, Sephadex LH-20, MCI and preparative HPLC. On the basis of chemical properties and spectra data, these compounds were identified as (2S)-liquiritigenin-4´-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranoside (1), (2R)-liquiritigenin-4´-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranoside (2), respectively. Compounds 1 and 2 are new compounds, and their aglycones are enantiomers.
Xanthine oxidase (XO) is a key enzyme in the synthesis of uric acid. Therefore, XO inhibitors play an important role in the antihyperuricemic therapy. Based on the template structures of febuxostat and topiroxostat, 18 amide derivatives were designed and synthesized. Among them, six showed apparent inhibitory activity against XO under the concentration of 10 μmol·L-1. Molecular docking revealed the possible interaction mode of this compound class, which may provide a clue for further molecular design.
This study was designed to establish a high performance liquid chromatography (diode array detector, DAD)-tandem mass chromatography (HPLC-DAD-MS/MS) method for the simultaneously screening 12 kinds of cough-relieving chemical drugs illegally added in anti-cough and antiasthmatic traditional Chinese medicines. This method involved liquid chromatography-tandem mass spectrometry. The separation was conducted by Kromasil100-5C18 (250 mm × 4.6 mm, 5 μm) and the mobile phase was consisted of 0.3% ammonium formate (pH 2.97) and methanol. After separated by HPLC, the suspected components were analyzed by MS/MS and DAD and ultra scan was used to identify these illegally added drugs. A fast and sensitive HPLC-DAD-MS/MS method for the simultaneously screening for illegal chemical compositions was established. The LOD of these substances were below 50 ng. The method was sufficiently selective and sensitive to detect illegal chemical compositions in anti-cough and antiasthmatic traditional Chinese medicines.
This study was designed to establish an ultra-liquid chromatography-mass spectrometry method for the reliable identification the multiple chemical components in Huangqi Jianzhong Tang (HQJZ). The ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry method was applied to identify the chemical constituents in the HQJZ rapidly. A total of 71 compounds including two major categories of saponins and flavonoids were identified or tentatively deduced on the basis of their retention behaviors, fragments of multistage mass spectrometry or by comparing with reference substances and literatures. Among them, 20 compounds were from Astragali Radix, 14 were from Paeoniae Radix Alba, 37 were from Glycyrrhizae Radix et Rhizoma Praeparata cum Melle, 3 were from Rhizoma Zingiberis Recens, 2 were from Cinnamomi Ramulus and Jujubae Fructus, respectively. The LC-MS method was used to qualitatively analyze the chemical constituents of HQJZ, which provides a scientific basis for the quality control of HQJZ.
A method of ultra flow liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed to elucidate the impurity of linezolid tablets. Linezolid was subjected to forced degradation under hydrolytic (acid, base and neutral), oxidative, photolytic and thermal. The structure identification of the degradation products and the fragmentation patterns for the related impurities were analyzed. A total of four degradation impurities were characterized, impurity 1 is (S)-1-amino-3-((3-fluoro-4-morpholinophenyl)amino)propan-2-ol, impurity 2 is (S)-4-(4-(5-(acetamidomethyl)-2-oxo-oxazolidin-3-yl)-2-fluorophenyl)morpholine 4-oxide, impurity 3 is (S)-5-(aminomethyl)-3-(3-fluoro-4-morpholinophenyl)oxazolidin-2-one, impurity 4 is (R)-N-(3-((3-fluoro-4-morpholinophenyl)amino)-2-hydroxypropyl)acetamide. Acid degradation induced impurity 3 and impurity 4, base degradation induced impurity 1 and impurity 4, oxidation degradation induced impurity 2, hydrolysis degradation induced impurity 4. The study also determined calibration factor using impurity references, and the calibration factors were found to be 1.3, 1.4, 0.9 and 1.1, respectively. The toxicity of the degradation impurities was predicted by web-based prediction system. The results from this study provide an important reference in quality control and evaluation of linezolid.
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