Cytochrome P450 3A4-Mediated Bioactivation and Its Role in Nomilin-Induced Hepatotoxicity.

Nomilin is a furan-containing triterpenoid isolated from the medicinal plants of citrus. The aim of this study was to investigate the in vitro and in vivo bioactivation of nomilin and the role in nomilin-induced hepatotoxicity. Microsomal incubations of nomilin supplemented with NADPH and GSH or NAL resulted in the detection of six conjugates (M1-M6). The structures of the metabolites were characterized based on LC-HRMS and NMR. Nomilin was bioactivated to a reactive cis-butene-dial (BDA) intermediate dependent on NADPH, and this intermediate suffered from the reaction with the nucleophiles (GSH and NAL) to form stable adducts. M1-M4 were identified as pyrrole derivatives, and M5 and M6 were pyrrolinone derivatives. M1 was further chemically synthesized and characterized by 13C NMR spectroscopy. M1 was the major metabolite detected in mice bile. Pretreatment with ketoconazole significantly reduced the formation of M1 in mice bile, while pretreatment with rifampicin significantly increased the formation of M1. Chemical inhibition together with recombinant human CYP450 phenotyping demonstrated that CYP3A4 was the major enzyme contributing to the bioactivation of nomilin. Toxicity study suggested that nomilin displayed dose-dependent liver injury in mice, while tetrahydro-nomilin was found to be nonhepatotoxic. Pretreatment with ketoconazole prevented mice from nomilin-induced liver injury. The liver injury induced by nomilin was deteriorated when the mice were pretreated with rifampicin. These findings provide evidence that CYP3A4-mediated bioactivation was indispensable in nomilin-induced hepatotoxicity.

Discovery of N-(4-(6-Acetamidopyrimidin-4-yloxy)phenyl)-2-(2-(trifluoromethyl)phenyl)acetamide (CHMFL-FLT3-335) as a Potent FMS-like Tyrosine Kinase 3 Internal Tandem Duplication (FLT3-ITD) Mutant Selective Inhibitor for Acute Myeloid Leukemia.

Most of the current FMS-like tyrosine kinase 3 (FLT3) inhibitors lack selectivity between FLT3 kinase and cKIT kinase as well as the FLT3 wt and internal tandem duplication (ITD) mutants. We report a new compound 27, which displays GI50 values of 30-80 nM against different ITD mutants and achieves selectivity over both FLT3 wt (8-fold) and cKIT kinase in the transformed BaF3 cells (>300-fold). 27 potently inhibits the proliferation of the FLT3-ITD-positive acute myeloid leukemia cancer lines through suppression of the phosphorylation of FLT3 kinase and downstream signaling pathways, induction of apoptosis, and arresting the cell cycle into the G0/G1 phase. 27 also displays potent antiproliferative effect against FLT3-ITD-positive patient primary cells, whereas it does not apparently affect FLT3 wt primary cells. In addition, it also exhibits a good therapeutic window to PBMC compared to PKC412. In the in vivo studies, 27 demonstrates favorable PK profiles and suppresses the tumor growth in the MV4-11 cell inoculated mouse xenograft model.

[Quality assessment and classification of persicae semen based on HPLC-UV fingerprint].

Persicae Semen (PS), a traditional Chinese medicine, has been widely used for the syndrome of blood stasis in China since the Eastern Han Dynasty. In the present study, we developed an HPLC-UV fingerprint analysis method for the quality control of PS. The HPLC fingerprint was performed on Shimadzu Inertsil C18 column (4.6 mm x 250 mm, 5 microm) at 35 degrees C. The mobile phases were composed of acetonitrile and water using a gradient elution. The flow rate was 1.0 mL x min(-1), and the detection wavelength was set at 210 nm. The fingerprint method was validated according to the Guidelines for Traditional Chinese Medicine Injection Fingerprint, and applied to determine 41 batches representative herbs collected from Xinjiang of China. The chromatographic peaks were characterized by UPLC-Q-TOF-MS, and nine of them were identified by comparison with the literature and/or reference standards. In order to classify and assess the samples, hierarchical clustering analysis and partial least square discriminant analysis were performed based on the common chromatographic peaks, and the samples were geographically classified into two classes, with six chemical compounds as classification markers which were significantly different between the two classes (P < 0.05).

Developmental toxicity and neurotoxicity of two matrine-type alkaloids, matrine and sophocarpine, in zebrafish (Danio rerio) embryos/larvae.

Matrine and sophocarpine are two major matrine-type alkaloids included in the traditional Chinese medicine (TCM) Kushen (the root of Sophora flavescens Ait.). They have been widely used clinically in China, however with few reports concerning their potential toxicities. This study investigated the developmental toxicity and neurotoxicity of matrine and sophocarpine on zebrafish embryos/larvae from 0 to 96/120h post fertilization (hpf). Both drugs displayed teratogenic and lethal effects with the EC50 and LC50 values at 145 and 240mg/L for matrine and 87.1 and 166mg/L for sophocarpine, respectively. Exposure of matrine and sophocarpine significantly altered spontaneous movement and inhibited swimming performance at concentrations below those causing lethality and malformations, indicating a neurotoxic potential of both drugs. The results are in agreement with most mammalian studies and clinical observations.

Effects of dietary factors on the pharmacokinetics of 58Fe-labeled hemin after oral administration in normal rats and the iron-deficient rats.

Hemin, iron (III) protoporphyrin chloride (IX), as a stable form of heme iron, has been used in iron absorption studies. The aim of the present study was to elucidate the influences of body iron status and three dietary factors (green tea extract, ascorbic acid, and calcium) on the pharmacokinetics of hemin using stable isotope labeling methods followed by ICP-MS measurement. In this study, a rapid, sensitive, and specific ICP-MS method for the determination of (58)Fe originating from hemin in rat plasma was developed and a rat model of iron deficiency anemia was established. It was found that hemin iron absorption increased significantly under iron deficiency anemia status, with AUC0-t and AUC0-∞ showing significant increase in anemic rats compared to normal ones. Green tea extract strongly inhibited hemin iron absorption in both normal rats and iron-deficient rats. In normal rats administered with green tea extract, C max resulted significantly reduced, whereas in anemic rats administered with green tea extract both AUC0-t and AUC0-∞ were reduced. On the other hand, ascorbic acid significantly affected hemin iron absorption only in iron-deficient rats, in which C max showed a significant increase. Interestingly, calcium slowed down the hemin iron absorption rate in normal rats, MRT0-t being significantly different in calcium-treated animals compared to untreated ones. This trend also appeared in the iron-deficient group but it did not reach statistical significance. Our data suggest that the mechanism of hemin iron absorption is regulated by body iron status and dietary factors can influence hemin iron absorption to varying degrees. Moreover, these results may also have general implication in the iron deficiency treatment with iron supplements and fortification of foods.

Determination of corosolic acid, a natural potential anti-diabetes compound, in rat plasma by high-performance liquid chromatography-mass spectrometry and its application to pharmacokinetic and bioavailability studies.

A simple, robust, and sensitive high-performance liquid chromatography/mass spectrometric method was developed for the determination of corosolic acid, a potential anti-diabetes substance, in rat plasma using glycyrrhetinic acid as the internal standard (IS). This method involved a liquid-liquid extraction with acetic ether and a subsequent analysis performed on an LC-MS system which contained an electrospray ionization interface. Chromatographic separation was performed using an ODS column, and the mobile phase was composed of methanol and 5 mmol/L ammonium acetate (88 : 12, v/v). Good linearity was observed over the concentration range of 20-10 ,000 ng/mL with a correlation coefficient (r² ≥ 0.995. The method was proved to be accurate and reliable and was applied to a pharmacokinetic study in the rat following intragastric and intravenous administration of corosolic acid.

[Determination of twelve elements in ephedrine extraction by microwave digestion-AAS].

The sample digested by microwave are of some merits: simple, rapid, saving agents, nonpollution and being easily digested. Microwave-digested sample with HNO3-H2O2 and AAS method were established for the determination of Fe, Ca, Mg, Zn, Mn, Cu, Na, K, Ni, Cd, Pb and Cr in ephedrine extraction. In this paper, the selection of digestion conditions, including pressure, power, acids and time of digestion was evaluated. According to standard sample GBW08501 Tea-leaves, we checked the method accuracy and precision. The accuracy values are in the range of 91.1%-105%. The RSDs of flame atomic spectrometry and graphite furnace atomic spectrometry are in the range of 0.2%-2.3% and less than 7%, respectively. The results are very consistent with the the reference values. It proved that the method has satisfactory precision and accuracy. The proposed method is simple, rapid, of nonpollution and safe. It was has been applied to the determination of trace elements in ephedrine extraction and provided useful data for production in factory.