143 Bulgarian Journal of Agricultural Science, 19 (2) 2013, 143–146 Agricultural Academy SAMBUCUS EBULUS L. FRUIT AQUEOUS INFUSION MODULATES GCL AND GPX4 GENE EXPRESSION O. TASINOV*, Y. KISELOVA-KANEVA and D. IVANOVA Medical University “Prof. Dr. P. Stoyanov”, Department of Biochemistry, Molecular Medicine and Nutrigenomics, BG – 9002 Varna, Bulgaria Abstract TASINOV, O., Y. KISELOVA-KANEVA and D. IVANOVA, 2013. Sambucus ebulus L. fruit aqueous infusion modulates GCL and GPx4 gene expression. Bulg. J. Agric. Sci., Supplement 2, 19: 143–146 Glutamate-cysteine ligase and glutathione peroxidase 4 are enzymes involved in cellular antioxidant defense. Biologically active compounds, such as polyphenols, may modulate their gene expression. Sambucus ebulus L. is a plant, which fruit infu- sions exhibits high antioxidant activity, due to its high polyphenol content. We analyzed the effect of Sambucus ebulus fruit aqueous infusion on glutamate-cysteine ligase catalytic subunit and glutathione peroxidase 4 gene expression levels in the presence and in the absence of oxidizing agent tert-butyl hydroperoxide in a 3T3-L1 preadipocyte cell culture model. Gene expression was analyzed by Real-Time qPCR, and relative gene expression levels were calculated using 2 –ΔΔCt method. Vi- ability of treated preadipocytes was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid reduction assay. In the range of 1.25% to 12.5% content of the infusion in the culture medium cell viability was not affected significantly. Glutamate-cysteine ligase mRNA levels were increased significantly (p < 0.05) after treatment. Pretreatment decreased tert- butyl hydroperoxide-induced gene expression of glutamate-cysteine ligase (p < 0.05) and of glutathione peroxidase 4 (p < 0.05). These data suggest that Sambucus fruit infusion exhibits strong antioxidant activity by modulating glutamate-cysteine ligase and glutathione peroxidase 4 gene expression. The study provides first scientific data about the antioxidant activity of Sambucus ebulus fruit infusion in a cell culture model. Key words: antioxidant, glutamate-cysteine ligase, glutathione peroxidase 4, Sambucus ebulus, 3T3-L1cells Abbreviations: GCLc – glutamate-cysteine ligase catalytic subunit; GPx4 – glutathione peroxidase 4; GSH – gluthatione; SE – Sambucus ebulus; FAI – fruit aqueous infusion; tButOOH – tert-butyl hydroperoxide; Real-Time qPCR – Real Time quantitative polymerase chain reaction; ROS – reactive oxygen species; cAMP – cyclic adenosine monophosphate; PKA – protein kinase A; ARE/EpRE – аntioxidant response element/electrophile response element; CREB – cAMP re- sponse element binding protein *E-mail: oskan@mail.bg Introduction GCL and GPx4 are enzymes involved in cell antioxidant defense. The cells respond to oxidative stress by increas- ing the expression of GCLc (Kobayashi et al., 2009). Thus, compounds modulating positively antioxidant enzymes gene expression may be considered potentially protective against oxidizing agents. Polyphenols are known to increase GSH levels by activating expression of GCLc (Myhrstad et al., 2002; Moskaug et al., 2005). Another enzyme, which activ- ity is related to GSH levels, is GPx4, and its expression is modulated by polyphenols (Oliva et al., 2011). Fruit juices, jams, teas from fruits and other preparations from dry and fresh fruits are rich in polyphenol compounds contributing to their antioxidant properties. Sambucus ebu- lus L. is a plant which fruit and flower infusions and extracts exhibit high antioxidant activity, due to high polyphenol content (Tasinov et al., 2012; Hosseinimehr et al., 2007;