О. P. Sen’, О. K. Оnufrovych, M. Ye. Kushynska, О. I. Pershyn,
А. S. Besedina, R. V. Fafula*, Z. D. Vorobets

Danylo Halytsky Lviv National Medical University, Ukraine;
*e-mail: roman_fafula@ukr.net

Received: 20 October 2025; Revised: 23 February 2026;
Accepted: 03 April 2026; Available on-line: April 2026

It is known that 1,4-naphthoquinone derivatives form the basis of a wide range of pharmaceuticals with diverse biological activities. A newly synthesized compound of this group – 11-(furan-2-yl)-9-hydroxy-3,11-dihydro-2H-benzo[6,7]thiochromeno[2,3-d]thiazole-2,5,10-trione, designated by Les-6400 laboratory code, is noteworthy for its drug-like properties. The aim of the study was to determine the parameters of glutathione antioxidant system in isolated human peripheral blood lymphocytes treated with Les-6400. Saponin-permeabilized lymphocytes from the blood samples of healthy male volunteers aged 20–44 years were used in the study. A significant dose-dependent increase in the lipid peroxidation process was observed upon lymphocytes exposure to Les-6400 at concentrations of 10^–5–10^–3 M. At the concentrations studied no effect of Les-6400 on GSH level was observed, while in the 10^–4–10^–3 M concentration range the activity of glutathione antioxidant enzymes was markedly affected: the activity of both glutathione peroxidase and glutathione reductase was increased, while that of glutathione-S-transferase was reduced. Thus, Les-6400 had a pronounced effect on the pro/antioxidant status of blood lymphocytes.