Inhibition of Acetylcholinesterase and Amyloid-β Aggregation by Piceatannol and Analogs: Assessing In Vitro and In Vivo Impact on a Murine Model of Scopolamine-Induced Memory Impairment

Comprehensive study on pharmacognostic, pharmacological, and toxicological features of Ficus racemosa in Alzheimer's disease using GC-MS and molecular docking analyses

Background

Alzheimer's disease (AD) presents as a widespread neurodegenerative condition impacting over 55 million individuals globally, with an annual rise of 10 million new cases. Despite its staggering prevalence, the absence of a definitive cure establishes the need for a revisit.

Methods

We explore the alternative strategies, focusing on the potential therapeutic efficacy of ethanolic extracts derived from the fruit and leaf of Ficus racemosa Linn.

Results

The investigation comprehensively explores pharmacognostic, phytochemical, toxicological, and pharmacological characteristics. In addition to pharmacognostic and physicochemical analyses, toxicological evaluations conducted on experimental animals demonstrated the innocuous nature of the ethanolic extracts (from both fruit and leaf) of F. racemosa, as evidenced by assessments of hemocompatibility, oxidative parameters, and vital organ histology. Phytochemical profiling via GC-MS identified 48 and 80 phytoconstituents in the fruit and leaf extracts, respectively. These constituents were screened for bioactive potential using the "Lipinski Rule of Five," resulting in the selection of 25 and 33 constituents from fruit and leaf extracts, respectively. Subsequent molecular docking studies against the AChE enzyme revealed promising interactions of the selected phytoconstituents. Furthermore, the top-scoring phytoconstituents were subjected to in silico screening to assess their interactions with β- and γ-secretase enzymes, in addition to the AChE enzyme. The cumulative findings substantiate the therapeutic utility of the plant extracts, particularly in the context of AD.

Conclusion

In conclusion, our investigation highlights the promising therapeutic potential of selected phytoconstituents derived from ethanolic extracts of F. racemosa in mitigating AD pathology by targeting key enzyme sites such as AChE, β-, and γ-secretase.

Enhanced Antioxidant and Neuroprotective Properties of Pterostilbene (Resveratrol Derivative) in Amorphous Solid Dispersions

In this study, amorphous solid dispersions (ASDs) of pterostilbene (PTR) with polyvinylpyrrolidone polymers (PVP K30 and VA64) were prepared through milling, affirming the amorphous dispersion of PTR via X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). Subsequent analysis of DSC thermograms, augmented using mathematical equations such as the Gordon-Taylor and Couchman-Karasz equations, facilitated the determination of predicted values for glass transition (Tg), PTR's miscibility with PVP, and the strength of PTR's interaction with the polymers. Fourier-transform infrared (FTIR) analysis validated interactions maintaining PTR's amorphous state and identified involved functional groups, namely, the 4'-OH and/or -CH groups of PTR and the C=O group of PVP. The study culminated in evaluating the impact of amorphization on water solubility, the release profile in pH 6.8, and in vitro permeability (PAMPA-GIT and BBB methods). In addition, it was determined how improving water solubility affects the increase in antioxidant (ABTS, DPPH, CUPRAC, and FRAP assays) and neuroprotective (inhibition of cholinesterases: AChE and BChE) properties. The apparent solubility of the pure PTR was ~4.0 µg·mL-1 and showed no activity in the considered assays. For obtained ASDs (PTR-PVP30/PTR-PVPVA64, respectively) improvements in apparent solubility (410.8 and 383.2 µg·mL-1), release profile, permeability, antioxidant properties (ABTS: IC50 = 52.37/52.99 μg·mL-1, DPPH: IC50 = 163.43/173.96 μg·mL-1, CUPRAC: IC0.5 = 122.27/129.59 μg·mL-1, FRAP: IC0.5 = 95.69/98.57 μg·mL-1), and neuroprotective effects (AChE: 39.1%/36.2%, BChE: 76.9%/73.2%) were confirmed.

Piceatannol selectively inhibited the JNK3 enzyme and augmented apoptosis through inhibition of Bcl-2/Cyt-c/caspase-dependent pathways in the oxygen-glucose deprived SHSY-5Y cell lines: In silico and in vitro study

JNK3, a neuronal kinase activated by stress, plays a role in stress-induced apoptosis, leading to neuronal cell death following cerebral ischemia. This study investigates the neuroprotective effects of piceatannol (PCT) in SHSY-5Y neuroblastoma cells after hypoxic injury and its interaction with JNK3. We analyzed the crystal coordinates, interaction energies, and amino acid interactions to determine PCT's selectivity for JNK3. The electrostatic potential was computed using density functional theory, while molecular dynamics assessed the stability and structural consistency of the JNK3-PCT complex. We used SP600125 (SP6), a JNK3 inhibitor, as a reference compound. Additionally, we performed cell-free JNK 1, 2, and 3 kinase assays to evaluate the isoform selectivity of PCT. Cytotoxicity and cell viability were determined by an MTT test. To assess apoptosis, we used acridine orange/ethidium bromide dual fluorescent labeling and ANNEXIN A5-FITC flow cytometry. Western blot was used to evaluate the attenuation of JNK3 and apoptotic proteins. In silico studies revealed a stronger binding affinity between PCT and JNK3 compared to JNK1 and JNK2, which was further supported by the in vitro kinase assay. PCT-treated cells exhibited a decrease in Cyt-c and caspase-3 expression and an increase in Bcl-2 level, compared to hypoxic control (p < .001). PCT also demonstrated superior efficacy over SP6 in inhibiting JNK3 phosphorylation (p < .001). Furthermore, PCT significantly increased the expression of neuronal genes, including NgN1, neuroD2, and survivin (p < .001). In conclusion, PCT is a potential JNK3 inhibitor, since it inhibited phosphorylation and the Bcl-2/Cyt-C/caspase-3-dependent apoptotic pathway after ischemic/hypoxic insult.

Extracts and Scirpusin B from Recycled Seeds and Rinds of Passion Fruits (Passiflora edulis var. Tainung No. 1) Exhibit Improved Functions in Scopolamine-Induced Impaired-Memory ICR Mice

In this paper, the seeds and rinds of passion fruit, which are the agricultural waste of juice processing, were recycled to investigate their biological activities for sustainable use. De-oiled seed powders (S) were successively extracted by refluxing 95% ethanol (95E), 50E, and hot water (HW), respectively, to obtain S-95EE, S-50EE, and S-HWE. Dried rind powders were successively extracted by refluxing HW and 95E to obtain rind-HWE and rind-95EE, respectively. S-50EE and S-95EE showed the most potent extracts, such as anti-amyloid-β1-42 aggregations and anti-acetylcholinesterase inhibitors, and they exhibited neuroprotective activities against amyloid-β25-35-treated or H2O2-treated SH-SY5Y cells. Scirpusin B and piceatannol were identified in S-95EE, S-50EE, and rind-HWE, and they showed anti-acetylcholinesterase activity at 50% inhibitory concentrations of 62.9 and 258.9 μM, respectively. Daily pretreatments of de-oiled seed powders and rind-HWE (600 mg/kg), S-95EE, and S-50EE (250 mg/kg) or scirpusin B (40 mg/kg) for 7 days resulted in improved learning behavior in passive avoidance tests and had significant differences (p < 0.05) compared with those of the control in scopolamine-induced ICR mice. The seeds and rinds of passion fruit will be recycled as materials for the development of functional foods, promoting neuroprotection and delaying the onset of cognitive dysfunctions.