Comparative pharmacokinetics study of five alkaloids in rat plasma and related compound-herb interactions mechanism after oral administration of Shuanghua Baihe tablets.

Shuanghua Baihe tablet is a traditional Chinese patent medicine which showed special advantages in the treatment of recurrent aphthous stomatitis. Scientists have improved and implemented the LC-MS/MS method, which is specific and sensitive, for comparative pharmacokinetics study of five alkaloids, including palmatine, berberine, epiberberine, jatrorrhizine and coptisine in rat plasma after oral administration of Rhizoma Coptidis extract and Shuanghua Baihe tablets. The results showed that Shuanghua Baihe tablets could promote the absorption of these five alkaloids and improved their bioavailability compared with R. Coptidis extract. To further investigate the related mechanism, everted intestinal sac model in vitro was used to indicate that alteration of in vivo pharmacokinetics of five alkaloids could be attributed to, at least in part, the absorption changes by coadministration of other herbs. These discoveries served as a theoretical basis for clinical use of Shuanghua Baihe tables.

Catechol-O-Methyltransferase and UDP-Glucuronosyltransferases in the Metabolism of Baicalein in Different Species.

BACKGROUND: Baicalein is the major bioactive flavonoid in some herb medicines and dietary plants; however, the detailed metabolism pathway of its major metabolite oroxylin A-7-O-ß-D-glucuronide in human was not clear. It was important to illustrate the major metabolic enzymes that participate in its elimination for the clinic use of baicalein. OBJECTIVES: We first revealed a two-step metabolism profile for baicalein and illustrated the combination of catechol-O-methyltransferase (COMT) and uridine diphosphate-glucuronosyltransferases (UGTs) in drug metabolism, further evaluated its bioactivity variation during drug metabolism. METHODS: The metabolism profiles were systematically characterized in different human biology preparations; after then, the anti-inflammatory activities of metabolites were evaluated in LPS-induced RAW264.7 cell. RESULTS: The first-step metabolite of baicalein was isolated and identified as oroxylin A; soluble-bound COMT (S-COMT) was the major enzyme responsible for its biotransformation. Specially, position 108 mutation of S-COMT significantly decreases the elimination. Meantime, oroxylin A was rapidly metabolized by UGTs, UGT1A1, -1A3, -1A6, -1A7, -1A8, -1A9, and -1A10 which were involved in the glucuronidation. Considerable species differences were observed with 1060-fold K m (3.05 ± 1.86-3234 ± 475 µM) and 330-fold CLint (5.93-1973 µL/min/mg) variations for baicalein metabolism. Finally, the middle metabolite oroxylin A exhibited a potent anti-inflammatory activity with the IC50 value of 28 µM. CONCLUSION: The detailed kinetic parameters indicated that COMT provide convenience for the next glucuronidation; monkey would be a preferred animal model for the preclinical investigation of baicalein. Importantly, oroxylin A should be reconsidered in evaluating baicalein efficacy against inflammatory diseases.

Comparative pharmacokinetic study of baicalin and its metabolites after oral administration of baicalin and Chaiqin Qingning capsule in normal and febrile rats.

An accurate, precise, selective, and sensitive high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of baicalin and its metabolite, baicalein 6-O-glucopyranuronoside, in normal and febrile rats plasma. Two analytes, along with hesperidin as an internal standard, were determined by multiple reactions monitoring (MRM) operated in the positive electrospray ionization (ESI) mode. Chromatographic separation was performed on an Agilent ZORBAX Extend-C18 column (100mm×2.10mm, 3.5µm) with a mobile phase of 0.1% formic acid solution and acetonitrile at a flow rate of 0.6mL/min. The calibration curves showed good linearity (r≥0.9974) with the concentration ranges of 2.000-2000ngmL-1 for baicalin and baicalein 6-O-glucopyranuronoside. The inter- and intra-day accuracies (relative error, RE%) were between -6.62% and 6.75%, and the precisions (relative standard deviation, RSD%) were less than 9.09% for quality control samples (QCs). The method also possessed good selectivity, recovery and stability, and was successfully applied to a comparative pharmacokinetic study of baicalin and baicalein 6-O-glucopyranuronoside in normal and febrile rats after oral administration of baicalin and Chaiqin Qingning capsule.

HPLC-Q-TOF-MS/MS Analysis of the Constituents in the Rat Biological Fluids After Oral Administration of Qing Ru Xiao granules.

A high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry method was established to detect as many constituents in rat biological fluids as possible after oral administration of Qing Ru Xiao granules (QRX). An Agilent Poroshell 120 EC-C18 column was adopted to separate the sample constituents, and mass spectra were acquired in positive and negative ion modes. First, the fingerprints of QRX were established, resulting in 28 components being detected within 30 min. Among these compounds, 11 were tentatively identified by comparing the retention times and mass spectral data with those of reference standards and the reference literature; the other 17 components were tentatively assigned solely based on the mass spectrometry data. Furthermore, metabolites in rat plasma and urine after oral administration of QRX were also analyzed. A total of 15 compounds were identified, including 13 prototypes and 2 metabolites through metabolic pathways of oxidation. This is the first systematic study on the metabolic profiling of QRX.

Identification of chemical constituents and rat metabolites of Kangxianling granule by HPLC-Q-TOF-MS/MS.

A high-performance liquid chromatography coupled with quadrupole time-of-flight mass tandem mass spectrometry method was established to characterize the chemical constituents of Kangxianling granule (KXL), a traditional Chinese medicine formula, and the metabolic profile in rat urine and plasma after oral administration of KXL. A total of 27 compounds in KXL extract and 13 prototype compounds with 12 metabolites in rat urine and plasma were identified. Among the 27 detected compounds, 15 were identified by comparing the retention time and MS data with that of reference compounds and the other 12 compounds were tentatively assigned based on the MS data and reference literature. The main prototype components absorbed in rat were amygdalin, salvianolic acid B, tanshinones and anthraquinones. Hydroxylation, glucuronidation and sulfation were the principal metabolic pathways in rat. The results revealed that the 25 compounds identified in rat urine and plasma were the potential active ingredients of KXL, which provides helpful chemical information for further study of the pharmacology mechanism of KXL.

Characterization of chemical constituents and rats metabolites of Shuanghua Baihe tablets by HPLC-Q-TOF-MS/MS.

A high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry method was established to detect as many constituents in rat biological fluids as possible after oral administration of Shuanghua Baihe tablets (SBT). An Agilent Poroshell 120 EC-C18 column was adopted to separate the samples, and mass spectra were acquired in positive and negative modes. First, the fingerprints of SBT were established, resulting in 32 components being detected within 40 min. Among these compounds, 12 were tentatively identified by comparing the retention times and mass spectral data with those of reference standards and the reference literature; the other 20 components were tentatively assigned solely based on the MS data. Furthermore, metabolites in rat plasma and urine after oral administration of SBT were also analyzed. A total of 19 compounds were identified, including 13 prototypes and six metabolites through metabolic pathways of demethylation and glucuronide conjugation. Glucuronidated alkaloids were the main constituents in the plasma, and were then excreted from urine. This is the first systematic study on the metabolic profiling of SBT.

Terpenoid indole alkaloids from Mappianthus iodoides Hand.-Mazz.

Ten terpenoid indole alkaloids, mappiodines A-C and mappiodosides A-G, together with eight known compounds, were isolated from stems of Mappianthus iodoides Hand.-Mazz. Their structures were elucidated by spectroscopic analyses including 1D, 2D NMR, MS and CD methods. The ten compounds were evaluated for their cytotoxic activity, but were inactive.

Caesalminaxins A-L, cassane diterpenoids from the seeds of Caesalpinia minax.

Fourteen new cassane diterpenoids, caesalminaxins A-L (1-14), and three known compounds were isolated from the seeds of Caesalpinia minax. Among the new diterpenoids, compounds 3 and 4 possess a rare spiro C/D ring system. The C-16 epimeric mixture 1/2 has an unprecedented carbon skeleton, presumably derived from 3 by cleavage of the C-13-C-14 bond. Compound 5 is the first example of a cassane diterpenoid with a spiro A/B ring system. The structures of the compounds were elucidated on the basis of 1D and 2D NMR analysis, and the absolute configurations of 3, 4, 9, and 11 were determined by single-crystal X-ray crystallography. Biosynthesis pathways for 1/2, 3, and 5 are postulated. Compounds 4, 8, and the known bonducellpin D exhibited moderate activity against four tested human cancer cell lines, HepG-2, K562, HeLa, and Du145.

Guanidine alkaloids from Plumbago zeylanica.

Eleven new guanidine alkaloids, plumbagines A-G (2-8) and plumbagosides A-D (9-12), as well as two known analogues (1, 13), were isolated from the aerial parts of Plumbago zeylanica. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR, MS, IR, and CD methods. The absolute configuration of 1 was determined by single-crystal X-ray diffraction of its derivative (1a).