bims-polyam 2020-12-27 papers

Issue of 2020–12–27
two papers selected by
Sebastian J. Hofer, University of Graz

Nutrients. 2020 Dec 17. pii: E3867. [Epub ahead of print]12(12):

Baicalein, 7,8-Dihydroxyflavone and Myricetin as Potent Inhibitors of Human Ornithine Decarboxylase.

Yun-Chin Liu, Yi-Liang Liu, Ju-Yi Hsieh, Chang-Hsu Wang, Chi-Li Lin, Guang-Yaw Liu, Hui-Chih Hung.

BACKGROUND: Human ornithine decarboxylase (ODC) is a well-known oncogene, and the discovery of ODC enzyme inhibitors is a beneficial strategy for cancer therapy and prevention.
METHODS: We examined the inhibitory effects of a variety of flavone and flavonol derivatives on ODC enzymatic activity, and performed in silico molecular docking of baicalein, 7,8-dihydroxyflavone and myricetin to the whole dimer of human ODC to investigate the possible binding site of these compounds on ODC. We also examined the cytotoxic effects of these compounds with cell-based studies.
RESULTS: Baicalein, 7,8-dihydroxyflavone and myricetin exhibited significant ODC suppression activity with IC50 values of 0.88 µM, 2.54 µM, and 7.3 µM, respectively, which were much lower than that of the active-site irreversible inhibitor α-DL-difluoromethylornithine (IC50, the half maximal inhibitory concentration, of approximately 100 µM). Kinetic studies and molecular docking simulations suggested that baicalein, and 7,8-dihydroxyflavone act as noncompetitive inhibitors that are hydrogen-bonded to the region near the active site pocket in the dimer interface of the enzyme. Baicalein and myricetin suppress cell growth and induce cellular apoptosis, and both of these compounds suppress the ODC-evoked anti-apoptosis of cells.
CONCLUSIONS: Therefore, we suggest that the flavone or flavonol derivatives baicalein, 7,8-dihydroxyflavone, and myricetin are potent chemopreventive and chemotherapeutic agents that target ODC.

Keywords: 7,8-dihydroxyflavone; chemoprevention; molecular docking simulations: baicalein; myricetin; ornithine decarboxylase

DOI: https://doi.org/10.3390/nu12123867

Plants (Basel). 2020 Dec 17. pii: E1790. [Epub ahead of print]9(12):

Exogenous Salicylic Acid Modulates the Response to Combined Salinity-Temperature Stress in Pepper Plants (Capsicum annuum L. var. Tamarin).

Ginés Otálora, María Carmen Piñero, Jacinta Collado-González, Josefa López-Marín, Francisco M Del Amor.

Growers in the cultivated areas where the climate change threatens the agricultural productivity and livelihoods are aware that the current constraints for good quality water are being worsened by heatwaves. We studied the combination of salinity (60 mM NaCl) and heat shock stress (43 °C) in pepper plants (Capsicum annuum L. var. Tamarin) since this can affect physiological and biochemical processes distinctly when compared to separate effects. Moreover, the exogenous application of 0.5 mM salicylic acid (SA) was studied to determine its impacts and the SA-mediated processes that confer tolerance of the combined or stand-alone stresses. Plant growth, leaf Cl- and NO3- concentrations, carbohydrates, and polyamines were analyzed. Our results show that both salinity stress (SS) and heat stress (HS) reduced plant fresh weight, and SA only increased it for HS, with no effect for the combined stress (CS). While SA increased the concentration of Cl- for SS or CS, it had no effect on NO3-. The carbohydrates concentrations were, in general, increased by HS, and were decreased by CS, and for glucose and fructose, by SA. Additionally, when CS was imposed, SA significantly increased the spermine and spermidine concentrations. Thus, SA did not always alleviate the CS and the plant response to CS cannot be directly attributed to the full or partial sum of the individual responses to each stress.

Keywords: NaCl; combined stress; extreme weather; heat shock stress; salinity; temperature

DOI: https://doi.org/10.3390/plants9121790