Alzheimer's disease (AD) is a progressive neurological disorder that impairs memory and cognitive abilities, primarily in the elderly. The burden of AD extends beyond patients, impacting families and caregivers due to the patients' reliance on assistance for daily tasks. The main features of the pathogenesis of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs), that strongly correlate with oxidative stress and inflammation. NFTs result from misfolded and hyperphosphorylated tau proteins. Various studies have focused on tau phosphorylation, indicating protein phosphatase 2A (PP2A) as the primary tau phosphatase and glycogen synthase kinase-3 beta (GSK-3β) as the leading tau kinase. Experimental evidence suggests that inhibition of PP2A and increased GSK-3β activity contribute to neuroinflammation, oxidative stress, and cognitive impairment. Hence, targeting PP2A and GSK-3β with pharmacological approaches shows promise in treating AD. The use of natural compounds in the drug development for AD have been extensively studied for their antioxidant, anti-inflammatory, anti-cholinesterase, and neuroprotective properties, demonstrating therapeutic advantages in neurological diseases. Alongside the development of PP2A activator and GSK-3β inhibitor drugs, natural compounds are likely to have neuroprotective effects by increasing PP2A activity and decreasing GSK-3β levels. Therefore, based on the preclinical and clinical studies, the potential of PP2A and GSK-3β as therapeutic targets of natural compounds are highlighted in this review.
Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline, memory impairment, and accumulation of amyloid-β (Aβ) plaques. While current treatments offer limited efficacy, medicinal plants such as Ficus deltoidea (FD), a traditional remedy, have shown promise due to their neuroprotective and anti-inflammatory properties. An AD-like phenotype was induced in male Wistar rats using D-galactose and aluminum chloride over 70 days. FD extract was administered orally at 50, 100, and 200 mg/kg. Spatial memory was evaluated using the T-maze test. Histological analyses of the hippocampi's Cornu Ammonis 1 and 3 (CA1 and CA3) regions were conducted via hematoxylin and eosin (H&E) staining, and Aβ plaques deposition was assessed with Congo red. Enzyme-linked immunosorbent assay (ELISA) was used to quantify hippocampal levels of Aβ (1-42) and β-secretase-1 (BACE-1). FD treatment significantly enhanced spatial memory, preserved pyramidal neuron integrity in CA1 and CA3, and reduced amyloid plaque formation. Biochemically, FD markedly decreased hippocampal Aβ (1-42) and BACE-1 concentrations in a dose-dependent manner. Thus, FD exhibits multi-target neuroprotective effects in an AD-like model, potentially via modulation of amyloidogenic pathways. Further studies are warranted to explore its mechanisms and therapeutic potential in other brain regions implicated in AD.