Traditionally used edible medicinal plants protect against rotenone induced toxicity in SH-SY5Y cells-a prospect for the development of herbal nutraceuticals

Plants are good sources of pharmacologically active compounds. The present study aimed to examine the neuroprotective potentials of the methanol extracts of Salix tetrasperma Roxb. leaf (STME) and Plantago asiatica L. (PAME), two edibles medicinal plants of Manipur, India against neurotoxicity induced by rotenone in SH-SY5Y cells. Free radical quenching activities were evaluated by ABTS and DPPH assays. The cytotoxicity of rotenone and the neuronal survival were assessed by MTT assay and MAP2 expression analysis. DCF-DA, Rhodamine 123 (Rh-123), and DAPI measured the intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and apoptotic nuclei, respectively. Superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were also assessed. LC-QTOF-MS analysis was performed for the identification of the compounds present in STME and PAME. The study showed that both the plant extracts (STME and PAME) showed antioxidant and neuroprotective capabilities in rotenone-induced neurotoxicity by preventing oxidative stress through the reduction of intracellular ROS levels and reversing the activities of GPx, SOD, and CAT caused by rotenone. Further, both plants prevented apoptotic cell death by normalizing the steady state of MMP and protecting nuclear DNA condensation. LC-QTOF-MS analysis shows the presence of known neuroprotective compounds like uridine and gabapentin in STME and PAME respectively. The two plants might be an important source of natural antioxidants and nutraceuticals with neuroprotective abilities. This could be investigated further to formulate herbal nutraceuticals for the treatment of neurodegenerative disease like Parkinson's disease.