The neuroprotective effects of Lonicera japonica THUNB. against hydrogen peroxide-induced apoptosis via phosphorylation of MAPKs and PI3K/Akt in SH-SY5Y cells

We investigated the neuroprotective effects of Lonicera japonica THUNB. (Caprifoliaceae) (LJ) extract against hydrogen peroxide (H₂O₂), a toxin created by oxidative stress and implicated in neurodegenerative diseases, in human SH-SY5Y neuroblastoma cells. We examined the effects of LJ against H₂O₂-induced cytotoxicity, apoptosis, the production of reactive oxygen species (ROS), the proteolysis of cleaved poly-ADP-ribose polymerase (PARP), and the expression of Bcl-2, Bcl-xL, and cleaved caspase-3. Moreover, we attempted to determine whether LJ suppressed the phosphorylation of Akt, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase 1/2 (ERK 1/2). We found that LJ improved cell viability, inhibited cytotoxicity and apoptosis, and attenuated elevations in ROS and nuclear condensation. In addition, LJ showed radical scavenging ability in 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS) assays. Western blot data revealed that LJ inhibited H₂O₂-induced up- and down-regulation of cleaved PARP, cleaved caspase-3, Bcl-2, and Bcl-xL. Furthermore, LJ significantly attenuated the H₂O₂-induced phosphorylation of Akt, JNK, p38 MAPK, and ERK1/2. These results demonstrate that LJ possesses potent neuroprotective activity. Its potential to treat neurodegenerative diseases warrants further research.