Oroxylum indicum (L.) Leaf Extract Attenuates β-Amyloid-Induced Neurotoxicity in SH-SY5Y Cells

Alzheimer's disease (AD) is characterized by the presence of amyloid-beta (Aβ) plaques, which trigger oxidative stress and neuronal cell death. The present study investigated the neuroprotective effects of Oroxylum indicum (L.) leaf (OIL) extract against Aβ-induced oxidative stress and cellular damage in SH-SY5Y cells. The cells were treated with OIL extract with and without Aβ25-35, and their viability was investigated. Moreover, the mechanism of action of OIL was assessed by determining caspase-3 levels, reactive oxygen species (ROS) and malondialdehyde (MDA) levels, enzymatic activity of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), phosphorylation of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), extracellular signal-regulated kinase 1 and 2 (ERK1/2), and cAMP-responsive element-binding protein (CREB), and expression of B-cell lymphoma-2 (Bcl-2) proteins. The results indicated that OIL reduced Aβ-induced neurotoxicity in a concentration-dependent manner, improving cell viability, reducing ROS levels and MDA production, increasing antioxidant enzyme activity of CAT, SOD, and GSH-Px, and decreasing caspase-3 expression. In addition, OIL enhanced phosphorylation of Akt, ERK1/2, and CREB and upregulated Bcl-2 protein expression. High-performance liquid chromatography (HPLC) analysis identified oroxylin A, baicalein, and chrysin as the major phenolic constituents of the OIL extract. The findings suggest that the extract holds promise as a therapeutic intervention against Aβ-induced neurotoxicity, offering potential implications for the treatment of AD. Further studies are needed to investigate the activity of OIL in primary neurons or in vivo.