Antioxidant effects of strawberry extract on HepG2 stressed with an oxidant agent

A common denominator in the pathogenesis of most common chronic diseases is the involvement of oxidative stress, defined as a persistent imbalance between the production of reactive oxygen species (ROS) and antioxidant defenses. When the production of ROS exceeds the capacity of antioxidant defenses, oxidative stress may arise, damaging the functional and structural integrity of cellular macromolecules, such as lipids, proteins and DNA. A strategy to alleviate oxidative damage could be the use of natural antioxidants derived from diet. In this context, strawberries (Fragaria ~ ananassa Duch.) possess a remarkable nutritional composition in terms of micronutrients such as minerals, vitamin C and folates, and non-nutrient elements, like phenolic compounds, that are essential for human health by exerting antioxidant effects. The overall goal of the present study was to investigate the potential of a polyphenol-rich strawberry extract to protect against oxidative stress. The strawberry extract was characterized for its nutritional and phytochemical contents, as well as for its antioxidant capacity. HepG2 cells were treated with 100 μg mL-1strawberry extract and then were stressed with 10 mM AAPH for 24 h to induce oxidative stress and cell viability, apoptosis rate, intracellular ROS and nitric oxide (NO) levels were assessed. Results showed that strawberry extract had a high content of total polyphenols, flavonoids and anthocyanins and a relevant total antioxidant capacity. In addition, a significant improvement in cell viability and apoptosis rate was found in cells treated with strawberry and stressed with AAPH, as well as a relevant decrease in intracellular ROS and NO levels. Our results confirm the capacity of strawberry extract to counteract oxidative stress, highlighting the utmost importance to plan and develop an in vivo study, in order to obtain a comprehensive description of the efficacy of strawberry bioactive compounds in oxidative stress-related diseases and elucidate their mechanisms of action.