Costunolide ameliorates rotenone-induced Parkinson's disease in rat model via activation of SIRT-1/p-AMPK cascade and suppression of IL-6/STAT3 axis

Costunolide (COST), a sesquiterpene lactone, has demonstrated promising potential in molecular docking studies targeting key proteins associated with Parkinson's disease (PD), particularly AMP-activated protein kinase (AMPK) and sirtuin-1 (SIRT1). Building on these preliminary findings, this study was designed to explore the in vivo neuroprotective effects of COST in a rotenone-induced PD model, aiming to substantiate its therapeutic efficacy. The evaluation focused on motor function, oxidative stress markers, neuroinflammatory indicators, and the balance between autophagy and apoptosis, alongside histopathological examination. Treatment with COST displayed an enhancement in motor performance, as observed by improved results in both the open-field and narrow beam walk tests. Concurrently, COST preserved dopaminergic neurons in the substantia nigra and boosted tyrosine hydroxylase immunoreactivity. Furthermore, COST reduced oxidative stress status via increasing SIRT-1 and PGC-1α content. Notably, COST suppressed neuroinflammation by inhibiting the IL-6R/STAT3/NFκBp65 /IL-6 signaling pathway. Additionally, COST stimulated autophagy via the activation of p-AMPK/ULK1/Beclin-1 cascade, facilitating the removal misfolded protein, α-synuclein. COST also reduced apoptosis by increasing Bcl-2 and decreasing Bax levels. In conclusion, COST exhibited promising neuroprotective effects against rotenone-induced PD in a rat model. This protection is mediated through the activation of the SIRT1/PGC-1α and p-AMPK/ULK1/Beclin-1 pathways, alongside the inhibition of the IL-6R/STAT3/NFκBp65 axis. Collectively, these mechanisms attenuated oxidative stress and neuroinflammation while restoring the balance between apoptosis and autophagy, positioning COST as a potential therapeutic candidate for Parkinson's disease.