The aim of our study was to determine the PPARγ agonism and hypoglycemic activity of natural phenolics isolated from Paulownia tomentosa and Morus alba. We started with a molecular docking preselection, followed by in vitro cell culture assays, such as PPARγ luciferase reporter gene assay and PPARγ protein expression by Western blot analysis. The ability of the selected compounds to induce GLUT4 translocation in cell culture and lower blood glucose levels in chicken embryos was also determined. Among the thirty-six plant phenolic compounds, moracin M showed the highest hypoglycemic effect in an in ovo experiment (7.33 ± 2.37%), followed by mulberrofuran Y (3.84 ± 1.34%) and diplacone (3.69 ± 1.37%). Neither moracin M nor mulberrofuran Y showed a clear effect on the enhancement of GLUT4 translocation or agonism on PPARγ, while diplacone succeeded in both (3.62 ± 0.16% and 2.4-fold ± 0.2, respectively). Thus, we believe that the compounds moracin M, mulberrofuran Y, and diplacone are suitable for further experiments to elucidate their mechanisms of action.

• Klíčová slova
• PPARγ, diabetes mellitus, hypoglycemic, natural products, plant phenolics,
• MeSH
• fenoly * chemie   farmakologie   izolace a purifikace   MeSH
• hypoglykemika * chemie   farmakologie   izolace a purifikace   MeSH
• kuřecí embryo MeSH
• lidé MeSH
• Morus * chemie   MeSH
• myši MeSH
• PPAR gama * agonisté   metabolismus   genetika   chemie   MeSH
• přenašeč glukosy typ 4 metabolismus   genetika   MeSH
• rostlinné extrakty * chemie   farmakologie   izolace a purifikace   MeSH
• simulace molekulového dockingu MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fenoly * MeSH
• hypoglykemika * MeSH
• PPAR gama * MeSH
• přenašeč glukosy typ 4 MeSH
• rostlinné extrakty * MeSH

Background: Oxidative stress is a key factor in the pathophysiology of many diseases. This study aimed to verify the antioxidant activity of selected plant phenolics in cell-based assays and determine their direct or indirect effects. Methods: The cellular antioxidant assay (CAA) assay was employed for direct scavenging assays. In the indirect approach, the influence of each test substance on the gene and protein expression and activity of selected antioxidant enzymes was observed. One assay also dealt with activation of the Nrf2-ARE pathway. The overall effect of each compound was measured using a glucose oxidative stress protection assay. Results: Among the test compounds, acteoside showed the highest direct scavenging activity and no effect on the expression of antioxidant enzymes. It increased only the activity of catalase. Diplacone was less active in direct antioxidant assays but positively affected enzyme expression and catalase activity. Morusin showed no antioxidant activity in the CAA assay. Similarly, pomiferin had only mild antioxidant activity and proved rather cytotoxic. Conclusions: Of the four selected phenolics, only acteoside and diplacone demonstrated antioxidant effects in cell-based assays.

• Klíčová slova
• CAA, Nrf2-ARE, antioxidants, catalase, glucose toxicity, plant phenolics, superoxide dismutase,
• MeSH
• antioxidační responzivní elementy MeSH
• antioxidancia chemie   farmakologie   MeSH
• biologické markery MeSH
• exprese genu MeSH
• faktor 2 související s NF-E2 genetika   metabolismus   MeSH
• fenoly chemie   farmakologie   MeSH
• glukosa MeSH
• lidé MeSH
• molekulární struktura MeSH
• oxidační stres MeSH
• protinádorové látky chemie   farmakologie   MeSH
• rostlinné extrakty chemie   farmakologie   MeSH
• superoxiddismutasa 1 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• biologické markery MeSH
• faktor 2 související s NF-E2 MeSH
• fenoly MeSH
• glukosa MeSH
• NFE2L2 protein, human MeSH Prohlížeč
• protinádorové látky MeSH
• rostlinné extrakty MeSH
• SOD1 protein, human MeSH Prohlížeč
• superoxiddismutasa 1 MeSH

Multidrug resistance (MDR) is a common problem when fighting cancer with chemotherapy. P-glycoprotein (P-gp, or MDR1) is an active pump responsible for the efflux of xenobiotics out of the cell, including anti-cancer drugs. It is a validated target against MDR. No crystal structure of the human P-gp is available to date, and only recently several cryo-EM structures have been solved. In this paper, we present a comprehensive computational approach that includes constructing the full-length three-dimensional structure of the human P-gp and its refinement using molecular dynamics. We assessed its flexibility and conformational diversity, compiling a dynamical ensemble that was used to dock a set of lignan compounds, previously reported as active P-gp inhibitors, and disclose their binding modes. Based on the statistical analysis of the docking results, we selected a system for performing the structure-based virtual screening of new potential P-gp inhibitors. We tested the method on a library of 87 natural flavonoids described in the literature, and 10 of those were experimentally assayed. The results reproduced the theoretical predictions only partially due to various possible factors. However, at least two of the predicted natural flavonoids were demonstrated to be effective P-gp inhibitors. They were able to increase the accumulation of doxorubicin inside the human promyelocytic leukemia HL60/MDR cells overexpressing P-gp and potentiate the antiproliferative activity of this anti-cancer drug.

• Klíčová slova
• P-glycoprotein, flavonoids, molecular docking, molecular dynamics, multidrug resistance, natural compounds, structure-based virtual screening,
• Publikační typ
• časopisecké články MeSH

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

• Klíčová slova
• Bignonia tomentosa, Flavonoid, Lignan, Paulownia tomentosa, Paulowniaceae, Phenolic glycosides,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND AND PURPOSE: Paulownia tomentosa is a rich source of geranylated flavanones, some of which we have previously shown to have cytotoxic activity. To identify members of this class of compounds with cytostatic effects, we assessed the effects of the geranylated flavanone tomentodiplacone B (TOM B) on cell cycle progression and cell cycle regulatory pathways of THP-1 human monocytic leukaemia cells. EXPERIMENTAL APPROACH: Cell viability was measured by dye exclusion and proliferation by WST-1 assays; cell cycle was monitored by flow cytometry. Regulatory proteins were assessed by immunoprecipitation and kinase assays, and Western blotting. KEY RESULTS: Tomentodiplacone B had no effect during the first 24 h of cell growth at concentrations between 1 and 2.5 µM, but inhibited cell growth in a dose-dependent manner at concentrations of 5 µM or higher. Growth inhibition during the first 24 h of exposure to TOM B was not accompanied by cytotoxicity as cells were accumulated in G1 phase dose-dependently. This G1 phase accumulation was associated with down-regulation of cyclin-dependent kinase 2 activity and also protein levels of cyclins E1 and A2. However, key stress-related molecules (γ-H2AX, p53 and p21) were not induced, suggesting that TOM B acts by directly inhibiting the cyclin-dependent kinase 2 signalling pathway rather than initiating DNA damage or cellular stress. CONCLUSIONS AND IMPLICATIONS: Our study provides the first evidence that TOM B directly inhibits proliferation of human monocytic leukaemia cells, and thus is a potential anticancer agent, preventing leukaemia cells from progressing from G1 phase into DNA synthesis.

• MeSH
• akutní monocytární leukemie MeSH
• antikarcinogenní látky farmakologie   MeSH
• cyklin D metabolismus   MeSH
• cyklin-dependentní kinasa 2 antagonisté a inhibitory   biosyntéza   metabolismus   MeSH
• cykliny metabolismus   MeSH
• down regulace účinky léků   MeSH
• flavanony farmakologie   MeSH
• G1 fáze účinky léků   MeSH
• lidé MeSH
• monocyty cytologie   účinky léků   metabolismus   MeSH
• monoterpeny farmakologie   MeSH
• nádorové buněčné linie MeSH
• proliferace buněk účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antikarcinogenní látky MeSH
• CDK2 protein, human MeSH Prohlížeč
• cyklin D MeSH
• cyklin-dependentní kinasa 2 MeSH
• cykliny MeSH
• flavanony MeSH
• monoterpeny MeSH
• tomentodiplacone B MeSH Prohlížeč