Evaluation of the Protective Effects of Sarains on H2O2-Induced Mitochondrial Dysfunction and Oxidative Stress in SH-SY5Y Neuroblastoma Cells.

Abstract

Sarains are diamide alkaloids isolated from the Mediterranean sponge Haliclona (Rhizoniera) sarai that have previously shown antibacterial, insecticidal and anti-fouling activities. In this study, we examined for the first time the neuroprotective effects of sarains 1, 2 and A against oxidative stress in a human neuronal model. SH-SY5Y cells were co-incubated with sarains at concentrations ranging from 0.01 to 10μM, and the well-known oxidant hydrogen peroxide at 150μM for 6h and the protective effects of the compounds were evaluated. Among the sarains tested, sarain A was the most promising compound, improving mitochondrial function and decreasing reactive oxygen species levels in human neuroblastoma cells treated with the compound at 0.01, 0.1 and 1μM. This compound was also able to increase the activity of the antioxidant enzymes superoxide dismutases by inducing the translocation of the nuclear factor E2-related factor 2 (Nrf2) to the nucleus at the lower concentrations tested (0.01 and 0.1μM). Moreover, sarain A at 0.1 and 1μM blocked the mitochondrial permeability transition pore (mPTP) opening through cyclophilin D inhibition. These results suggest that the protective effects produced by the treatment with sarain A are related with its ability to block the mPTP and to enhance the Nrf2 pathway, indicating that sarain A may be a candidate compound for further studies in neurodegenerative diseases.