Abstract

The combined action of both endogenous and exogenous factors stimulates the production of free radicals and reactive oxygen species (ROS) in cells. They are neutralized by an elaborate antioxidant defense system, superoxide dismutase (SOD) being the first line of enzymes involved in ROS scavenging. However, when ROS production cannot be counteracted by cellular antioxidant mechanisms oxidative stress happens, inducing damages in proteins, lipids and DNA. It had been suggested that antioxidant supplementation may help to reduce oxidative stress. TetraSOD^® is a unique marine healthy and functional ingredient that is produced under patent-protected technology, which exhibits a balanced nutritional composition and a significantly high SOD activity (>30,000 U/g). In this work, the antioxidant bioactivity of TetraSOD^® in muscle cells (Normal Human Skeletal Muscle Myoblasts, HSMMs) was examined using an in vitro approach. Three different doses of SOD activity in TetraSOD^® extracts were tested in cells: 30, 150 and 1500 U/ml. A statistically significant induction of the primary antioxidant enzyme activities, SOD, glutathione peroxidase (GPx), and catalase (CAT) was observed at the two higher doses in relation to the control. These results were further related to the expression of a selected set of genes involved in response against oxidative stress. A significant up-regulation of SOD1, SOD2, GPx1, CAT, NRF2 and HMOX1 was detected after TetraSOD^® treatment with regard to the control, exhibiting different patterns in response to the applied dose to cells. Overall, the results obtained in this study might represent an important contribution to the understanding of the molecular basis underlying the potential cytoprotective effects induced by TetraSOD^® consumption.

Key words: TetraSOD^®, Tetraselmis chuii, oxidative stress, antioxidant, gene expression, enzyme activity, SOD, NRF2.