Neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease are characterized by the progressive loss of
neurons. One of the contributing factors for these diseases is oxidative stress, characterized by the imbalance of free
radicals production and antioxidant defense mechanisms. In the present study, the neuroprotective effects of Ocimum
basilicum var. thyrsiflora against hydrogen peroxide (H2
O2
)-induced oxidative stress in SK-N-SH neuroblastoma cells
were evaluated. The exposure of SK-N-SH cells to 50 µM H2
O2
for 24 h induced cytotoxicity and apoptosis as measured
by cell viability and flow cytometry, respectively. Pretreatment with ethyl acetate (ObEA) fraction at 3.1-25 µg/mL showed
the highest protection against H2
O2
-induced cell death compared to other fractions and crude extract by increasing cell
viability and reducing apoptosis. The evaluation of antioxidant capacity via 1, 1-diphenyl-2-picrylahydrazyl (DPPH)
and ferric reducing/antioxidant power (FRAP) assays showed ObEA possessed the highest antioxidative properties. The
intracellular reactive oxygen species (ROS) production of H2
O2
in untreated cells increased by 2.39-fold compared to the
control and was significantly attenuated by the 2 h pre-treatment of O. basilicum (p<0.05). The reduction in intracellular
superoxide dismutase (SOD) induced by H2
O2
was also abrogated by the pretreatment of O. basilicum. These findings
suggested that O. basilicum is potentially neuroprotective against oxidative damage in neuronal cells by scavenging free
radicals, restoring SOD activities and eventually prevent cell death.