Neuroprotective effects of Premna integrifolia nano-phytosomes in haloperidol-induced Parkinson's rat model: A computational-guided Olivil nanoformulation delivery approach.

Parkinson’s disease (PD) is an age-associated neurodegenerative disorder. While allopathic treatments offer symptomatic relief, they are often associated with side effects and reduced long-term efficacy. Hence, there is a need to bridge the gap between allopathic therapies, plant bioactives and optimized delivery systems for effective neurodegenerative disease Parkinsonism management. In contrast, plant-based therapies such as Premna integrifolia L. offer multifaceted mechanisms, enhanced bioavailability through nanophytosome delivery, blood-brain barrier permeability, and cost-effectiveness. This study aimed to evaluate, characterize, and optimize nanophytosome-loaded P. integrifolia in a haloperidol-induced PD model. Hydroalcoholic extract (HEPI, 250 mg/kg), phytosomal formulation (PHYPI, 250 mg/kg), and fraction (FPI, 100 mg/kg) were administered over 36 days. In silico molecular docking and simulations identified olivil as a potent constituent with high binding affinity to GRIA2 and ADRB2, surpassing Levodopa. Phytosomes were prepared using thin-film hydration and characterized via particle size, PDI, zeta potential, SEM, TEM, FTIR, and LC-MS. In vitro assays evaluated total phenolic/flavonoid content, oxidative stress markers (SOD, GSH, MDA), protein and dopamine levels, and inhibition of AChE, BChE, and MAO-B. In vivo assessments included behavioral tests (catalepsy, actophotometer, balance beam, rotarod) and histopathological analysis of the hippocampus and cortex. PHYPI250 significantly improved motor performance and elevated dopamine levels, while reducing oxidative stress. Olivil-GRIA2 complexes showed enhanced stability with up to five hydrogen bonds. Pro-inflammatory cytokines IL-6 and TNF-α were markedly suppressed. Enzymatic assays showed significant inhibition of AChE, BChE, and MAO-B. Histological evaluation showed preserved neuronal integrity in CA1 and CA3 regions with minimal degeneration. P. integrifolia phytosomes exhibit promising therapeutic potential in PD through antioxidant, anti-inflammatory, and neuroprotective mechanisms. Olivil demonstrates superior molecular binding and stability.