In this study, we developed a new liquid chromatography-mass spectrometry (LC-MS) method for analysis of the protoberberine alkaloid palmatine and its metabolites with separation performed on a cyanopropyl-modified stationary phase. Palmatine (10 μM) was metabolized using suspensions of human hepatocytes and human recombinant cytochrome P450 (CYP) enzymes. Our analyses using electrospray ionization-quadrupole time-of-flight mass spectrometry revealed that palmatine was relatively resistant to the metabolic activity of human hepatocytes and recombinant CYP enzymes. However, we found that the biotransformation of palmatine in human hepatocytes included O-demethylation or hydroxylation, and that the product of palmatine demethylation was conjugated by glucuronidation or sulfation. Moreover, we found that human recombinant CYP2D6 and, to a lesser extent, CYP1A2 can mediate O-demethylation of palmatine. These results provide fundamental insights into the biotransformation of palmatine in human in vitro models and, together with the LC-MS method, can be applied for further studies on the biotransformation of palmatine and other protoberberine alkaloids.

• Klíčová slova
• CYP2D6, Cytochrome P450, Mass spectrometry, Metabolism, Palmatine,
• MeSH
• berberinové alkaloidy metabolismus   MeSH
• biotransformace MeSH
• dospělí MeSH
• hepatocyty metabolismus   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• rekombinantní proteiny metabolismus   MeSH
• systém (enzymů) cytochromů P-450 fyziologie   MeSH
• tandemová hmotnostní spektrometrie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• berberinové alkaloidy MeSH
• palmatine MeSH Prohlížeč
• rekombinantní proteiny MeSH
• systém (enzymů) cytochromů P-450 MeSH

Some 8-substituted derivatives of the protoberberine alkaloids palmatine (1a) and berberine (1b) have been prepared and investigated by 1D and 2D NMR spectroscopy (H-1, C-13, N-15). Complete NMR data for the 8-hydroxy (2), 8-methoxy (3), 8-ethoxy (4), and 8-trichloromethyl (5) 7,8-dihydro derivatives of 1a and 1b, as well as X-ray data for 8-methoxydihydroberberine (3b), 8-trichloromethyldihydropalmatine (5a), and 8-trichloromethyldihydroberberine (5b), are presented. The physicochemical data for all of these compounds are reviewed and compared with previously published values.

• MeSH
• alkaloidy chemická syntéza   chemie   MeSH
• berberin chemická syntéza   chemie   MeSH
• berberinové alkaloidy chemická syntéza   chemie   MeSH
• Berberis chemie   MeSH
• krystalografie rentgenová MeSH
• léčivé rostliny chemie   MeSH
• molekulární konformace MeSH
• molekulární struktura MeSH
• nukleární magnetická rezonance biomolekulární MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• alkaloidy MeSH
• berberin MeSH
• berberinové alkaloidy MeSH
• palmatine MeSH Prohlížeč

The protoberberine alkaloid palmatine is present in preparations from medicinal plants such as Coptis chinensis and Corydalis yanhusuo. This study examined whether palmatine affects the expression of cytochromes P450 (CYPs) 1A1 and 1A2 in primary cultures of human hepatocytes and human hepatoma HepG2 cells grown as monolayer or spheroids. Gene reporter assays showed that palmatine significantly activated the aryl hydrocarbon receptor (AhR) and increased the activity of CYP1A1 gene promoter in transiently transfected HepG2 cells. In HepG2 monolayer culture, palmatine also significantly increased mRNA and activity levels of CYP1A1, albeit with considerably less potency than 2,3,7,8-tetrachlorodibenzo-p-dioxin, a prototypical CYP1A inducer. On the other hand, CYP1A activity was not significantly elevated by palmatine in HepG2 spheroids. Moreover, palmatine induced mild or negligible changes in CYP1A1 and CYP1A2 mRNA expression without affecting CYP1A activity levels in primary human hepatocytes. It is concluded that palmatine activates the AhR-CYP1A pathway in HepG2 monolayer, while the potential for CYP1A induction is irrelevant in cell systems which are closer to the in vivo situation, i.e. in HepG2 spheroids and primary cultures of human hepatocytes. Possible induction of CYP1A enzymes by palmatine in vivo remains to be investigated.

• Klíčová slova
• Alkaloid, Aryl hydrocarbon receptor, CYP1A1, Cytochrome P450, Herb–drug interactions, Palmatine,
• MeSH
• berberin chemie   farmakologie   MeSH
• berberinové alkaloidy chemie   farmakologie   MeSH
• buňky Hep G2 MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• cytochrom P-450 CYP1A2 genetika   metabolismus   MeSH
• hepatocyty účinky léků   MeSH
• lidé MeSH
• molekulární struktura MeSH
• receptory aromatických uhlovodíků genetika   metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• transkripční faktory bHLH genetika   metabolismus   MeSH
• viabilita buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AHR protein, human MeSH Prohlížeč
• berberin MeSH
• berberinové alkaloidy MeSH
• CYP1A1 protein, human MeSH Prohlížeč
• CYP1A2 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A1 MeSH
• cytochrom P-450 CYP1A2 MeSH
• palmatine MeSH Prohlížeč
• receptory aromatických uhlovodíků MeSH
• transkripční faktory bHLH MeSH

There is an increasing interest in the study of guanine or cytosine-rich sequences that may fold into G-quadruplex (G4) or i-motif (iM) structures showing a short hairpin (or stem-loop) stabilized by Watson-Crick base pairs. These hybrid spatial arrangements may be target of ligands that have been shown to interact strongly with B-DNA. In this work, the interaction of the palmatine alkaloid with several sequences forming different G4s, iMs, and hybrid structures has been studied by means of spectroscopic and separation techniques, as well as multivariate data analysis methods. At the experimental conditions used in this work, the results have shown that this ligand strongly stabilizes parallel G4 structures, whereas a weaker interaction was observed with the antiparallel G4 adopted by the thrombin-binding aptamer or iMs. The presence of hairpins within the loops scarcely affects the affinity of this ligand for the hybrid G4/duplex or iM/duplex structures. Fluorescence measurements have provided evidence of a certain interaction with iMs at pH 5.1, despite the absence of thermal stabilization effects.

• Klíčová slova
• Binding, G-quadruplex, Hybrid structures, Palmatine, i-motif,
• MeSH
• berberinové alkaloidy * chemie   MeSH
• DNA chemie   MeSH
• G-kvadruplexy * MeSH
• ligandy MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• berberinové alkaloidy * MeSH
• DNA MeSH
• ligandy MeSH
• palmatine MeSH Prohlížeč

Adducts of the quaternary protoberberine alkaloids (QPA) berberine, palmatine, and coptisine were prepared with nucleophiles derived from pyrrole, pyrazole, imidazole, and 1,2,4-triazole. The products, 8-substituted 7,8-dihydroprotoberberines, were identified by mass spectrometry and 1D and 2D NMR spectroscopy, including (1)H--(15)N shift correlations at natural abundance. In addition, two adducts of QPA with chloroform and methanethiolate were characterized by using NMR data. Single-crystal X-ray structures of 8-pyrrolyl-7,8-dihydroberberine, 8-pyrazolyl-7,8-dihydroberberine, and 8-imidazolyl-7,8-dihydroberberine are also presented.

• MeSH
• alkaloidy chemie   MeSH
• azoly chemie   MeSH
• berberin analogy a deriváty   chemie   MeSH
• berberinové alkaloidy chemická syntéza   chemie   MeSH
• hmotnostní spektrometrie MeSH
• krystalografie rentgenová MeSH
• magnetická rezonanční spektroskopie MeSH
• organická chemie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alkaloidy MeSH
• azoly MeSH
• berberin MeSH
• berberinové alkaloidy MeSH
• coptisine MeSH Prohlížeč
• palmatine MeSH Prohlížeč
• protoberberine MeSH Prohlížeč