engleski

IN VITRO EFFECT THE MYRICETIN ON THE GLUTATHION S-TRANSFERASE (GSTs) ACTIVITY AND FREE THIOL GROUPS CONCENTRATION IN THE HEP G2 CELLS IN HYPERGLICAEMIC CONDITIONS

Myricetin is flavonol, consisting of 3-hydroxyflavone backbone and 6 hydroxyl groups. Myricetin exerts a wide variety of biological effects, including antioxidant and free radical-scavenging activities. Impaired glucose matabolism and protein glycation leads to oxidative stress. Glutathione S-transferase (GSTs) (EC.2.5.1.18) are enzymes responsible for the metabolism of numerous xenobiotics and play a major cellular antioxidant role. The low-molecular-weight thiols (free thiol groups) present in many proteins (cysteine and methionine residues) and peptides (e.g., glutathione or GSH) also play an important role in the cellular antioxidant defense system and regulation of protein functions. The aims of the present study were to investigate effect low concentration of the myricetin (Sigma, Co) on the activities GSTs and concentration of the free thiol groups in Hep G2 cells. The Hep G2 cells were treated with low concentrations of myricetin in a range 10-5 bis 10-9 M and glucose (20 mM) for 24 h. GSTs activities in Hep G2 cells was determined using spectrophotometric method described by Habdous et. al. and concentration of the free thiol groups was measured according to the Ellman, s assay using 5, 5, - dithiobis, 2-nitrobenzoic acid (DTNB). The results show that myricetin in a concentration of 10-7 M increase GSTs activity in Hep G2 cells when compared with sample treated only with 20 mM glucose p 0.05. Concentration of the free thiol groups was lower in cells treated with myricetin in a concentration of 10-5 M (p 0.05). Myricetin in concentration 10-7 M didn, t effect on the concentration free thiol groups in Hep G2 cells (p0.05).

myricetin; glutathion S-transferase (GST); free thiol groups; Hep G2 cells; hyperglicaemia

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