European Pharmaceutical Journal (Nov 2019)

Tannins, novel inhibitors of the volume regulation and the volume-sensitive anion channel

  • Tsiferova N.A.,
  • Khamidova O. J.,
  • Amonov A. U.,
  • Rakhimova M. B.,
  • Rustamova S. I.,
  • Kurbannazaova R. Sh.,
  • Merzlyak P. G.,
  • Abdulladjanova N. G.,
  • Sabirov R. Z.

DOI
https://doi.org/10.2478/afpuc-2019-0016
Journal volume & issue
Vol. 66, no. 2
pp. 37 – 44

Abstract

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The volume-sensitive outwardly rectifying anion channel (VSOR) is a key component of volume regulation system critical for cell survival in non-isosmotic conditions. The aim of the present study was to test the effects of four tannin extracts with defined compositions on cell volume regulation and VSOR. Preparation I (98% of hydrolysable tannins isolated from leaves of sumac Rhus typhina L.) and Preparation II (100% of hydrolysable tannins isolated from leaves of broadleaf plantain Plantago major L) completely and irreversibly abolished swelling-activated VSOR currents in HCT116 cells. Both preparations profoundly suppressed the volume regulation in thymocytes with half-maximal effects of 40.9 μg/ml and 12.3 μg/ml, respectively. The inhibition was more efficient at lower concentrations but reverted at higher doses due to possible non-specific membrane-permeabilizing activity. Preparations III and IV (54,7% and 54.3% of hydrolysable tannins isolated, respectively, from roots and aboveground parts of Fergana spurge Euphorbia ferganensis B.Fedtch) inhibited VSOR activity in a partially reversible manner and suppressed the volume regulation with substantially higher half-maximal doses of 270 and 278 μg/ml, respectively, with no secondary reversion at higher doses. Hydrolysable tannins represent a novel class of VSOR channel inhibitors with the capacity to suppress the cell volume regulation machinery.

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