Gogi berries are widely used in China both as food and as herbal medicines due to their variety of biological activities. Since oxidative stress is known to be a major cause of the development of several diseases, in this study we evaluated of the antioxidant potential of methanolic extracts of Lycium ruthenicum (Lr) and Lycium barbarum (Lb) in HepG2 cell line using t-BHP (0,5 mM) and paraquat (2 mM) as oxidative insults (4h). Lycium extracts, showed no significant citotoxicity up to 100 μg/ml and 24h incubation time with cells. Firstly, the extracts were pre-incubated for 2 and 6h before the application of t-BHP and paraquat, respectively. After, the extracts were pre-incubated for 20h before the application of insults. Cellular viability (MTT assay) was assessed immediately or 16h later, after oxidant insults. In short pre-incubation assays, Lr (100 μg/ml) showed significant cytoprotection against t-BHP and paraquat insults with 0,74- and 0,56-fold increases in cellular viability, respectively. In the long pre-incubation assay, both Lr and Lb showed significant protection against t-BHP toxicity with 9,9- and 1.7-fold increases in cellular viability at 100 μg/ml and 250 μg/ml, respectively. Using flow cytometry, Lr (100 μg/ml) triggered a significant decrease (less 38%) in apoptotic cells (FITC-Annexin) following long oxidant pre-incubation regimen. Additionally, in the short pre-incubation assay Lr showed a 0,55-fold decrease in reactive oxidative species (determined by DCFH-DA). Further studies, are necessary to understand the antioxidant and cytoprotective activities of Lr.
This work is financed by INTERACT - ISAC project no. NORTE-01-0145-FEDER-000017, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020, Portugal), and Key Construction Program of International Cooperation Base in S&T, Shaanxi Province (China, nº 2015SD0018).