Integrated systems pharmacology, molecular docking, and MD simulations investigation elucidating the therapeutic mechanisms of BHD in Alzheimer's disease treatment.

Abstract

Alzheimer's disease (AD) poses a longstanding health challenge, prompting a century-long exploration into its etiology and progression. Despite significant advancements in medical science, current AD treatments provide only symptomatic relief, urging a shift towards innovative paradigms. This study, departing from the amyloid hypothesis, integrates Systems Pharmacology, Molecular Docking and Molecular Dynamic Simulations to investigate a polyherbal phytoformulation (US 7,273,626 B2) rooted in Ayurveda for AD, consisting of Bacopa monnieri, Hippophae rhamnoides, and Dioscorea bulbifera (BHD). Diosgenin emerges as a crucial compound, aligning with previous studies, yet recognizing its limitations in explaining BHD's mechanism, this research delves into the intricate network of interactions. Protein-Protein Interaction (PPI) network analysis identifies hub genes (ALOX5, GSK3B, ACHE, SRC, AKT1, EGFR, PIK3R1, ESR1 and APP), suggesting a systems-level modulation of AD. Enrichment analyses unveil 370 AD-associated genes and key terms like "Cellular Response to Chemical Stimulus" and "Regulation of Biological Quality." KEGG pathway analysis underscores BHD's potential in Alzheimer's disease pathway (hsa05010), Endocrine resistance (hsa01522), and PI3K-Akt signaling (hsa04151). Molecular docking, carefully selecting compounds (Kaempferol, Quercetin, Myricetin, Isorhamnetin, Beta-Sitosterol, Stigmasterol, Emodin and Diosgenin) and top modulated targets, validates interactions with high dock scores, providing promising therapeutic avenues. Two core targets, Acetylcholinesterase (AChE) and Estrogen Receptor 1 (ESR1), were identified for further investigation due to their critical roles in Alzheimer's disease. To validate the molecular docking results, Molecular Dynamics (MD) simulations were performed on the AChE complexes with Myricetin, Beta-Sitosterol, and Stigmasterol, as well as the ESR1 complexes with Emodin, Diosgenin, and Beta-Sitosterol. These simulations were then compared to the interactions observed with the marketed drugs Donepezil and Estradiol, which are commonly used in Alzheimer's treatment. The MD simulations provided detailed insights into the stability and behavior of these complexes over time. The findings indicated that Myricetin and Emodin not only maintained stable interactions with AChE and ESR1 but also exhibited greater stability than Donepezil and Estradiol at specific time points and protein regions, as demonstrated by lower RMSD and RMSF values. These results suggest that natural compounds hold promise as potential therapeutic agents in the treatment of Alzheimer's disease, offering new avenues for drug development, while the formulation BHD shows potential as an adjuvant in integrative medicine alongside standard Alzheimer's treatments, effectively targeting related pathways and genes.