Structural alterations in the catalytic core of hSIRT2 enzyme predict therapeutic benefits of Garcinia mangostana derivatives in Alzheimer's disease: molecular dynamics simulation study

Discovery of phenylcarbamoyl xanthone derivatives as potent neuroprotective agents for treating ischemic stroke

Compounds of natural sources are widespread discovered in the treatment of ischemic stroke. Alpha-mangostin, a natural prenylated xanthone, has been found to display a therapeutic potential to treat ischemic stroke. However, the direct application of α-mangostin is limited due to its cytotoxicity and relatively low efficacy. Herein, structural modification of α-mangostin was necessary to improve its drug-ability. Currently, 34 α-mangostin phenylcarbamoyl derivatives were synthesized and evaluated for their neuroprotective activities by glutamate-induced excitotoxicity and H₂O₂-induced oxidative damage models in vitro. The results showed that compound 2 had the most therapeutic potential in both models. Whereafter, 2 has been proved to have powerful therapeutic effects by the MCAO ischemic stroke model in rats, which might be due to inhibition of inflammatory reaction and free radical accumulation. Besides, acute toxicity assay in rats showed that compound 2 had excellent safety. Overall, 2 could be a promising neuroprotective agent for the treatment of ischemic stroke deserving further investigations.

Mangosteen Metabolites as Promising Alpha-Amylase Inhibitor Candidates: In Silico and In Vitro Evaluations

Diabetes is a chronic metabolic disorder characterized by raised glucose levels in the blood, resulting in grave damage over time to various body organs, including the nerves, heart, kidneys, eyes, and blood vessels. One of its therapeutic treatment approaches involves the inhibition of enzymes accountable for carbohydrate digestion and absorption. The present work is aimed at evaluating the potential of some reported metabolites from Garcinia mangostana (mangosteen, Guttiferae) as alpha-amylase inhibitors. Forty compounds were assessed for their capacity to inhibit alpha-amylase using in silico studies as well as in vitro assays. Molecular docking was carried out to analyze their binding capacities in the 3D structure of alpha-amylase (PDB ID: 4GQR). Among the tested compounds, 6-O-β-D-glucopyranosyl-2,4,6,3',4',6'-hexahydroxybenzophenone (8), aromadendrin-8-C-glucoside (5), epicatechin (6), rhodanthenone (4), and garcixanthone D (40) had a high XP G.score and a Glide G.score of -12.425, -11.855, -11.135, and -11.048 Kcal/mol, respectively. Compound 8 possessed the XP and Glide docking score of -12.425 Kcal/mol compared to the reference compounds myricetin and acarbose which had an XP and Glide docking score of -12.319 and 11.201 Kcal/mol, respectively. It interacted through hydrogen bond formations between its hydroxyl groups and the residues His 101, Asp 197, Glu 233, Asp 300, and His 305, in addition to water bridges and hydrophobic interactions. Molecular mechanics-generalized born surface area (MM-GBSA) was used to calculate the binding free energy and molecular dynamic studies that indicated the stability of the alpha-amylase-compound 8 complex during the 100 ns simulation in comparison with myricetin- and acarbose-alpha-amylase complexes. Additionally, the in vitro alpha-amylase inhibition assay findings validated the in silico study's findings. This could further validate the potential of G. mangostana as a candidate for diabetes management.

Mechanistic Insights into the Selective Dual BET and PLK1 Inhibitory Activity of a Novel Benzamide Compound in Castration-Resistant Prostrate Cancer

Though multifactorial, BET and PLK1 proteins have been found to be key players in the oncogenic process leading to castration-resistant prostate cancer through regulation of AR and MYC-mediated transcription. Hence, dual inhibition of these proteins appears to be an auspicious approach for CRPC therapy. WNY0824 has been reported to exhibit nanomolar range inhibition as well as significant anti-proliferative activity on AR-positive CRPC cells in vitro. However, structural, and mechanistic events associated with its dual inhibitory and anti-proliferative mechanisms remain unclear. Utilizing integrative computer-assisted atomistic techniques, analyses revealed that the dual-inhibitory activity of WNY0824 against BRD4 and PLK1 proteins is mediated by conserved residues present in the binding cavities of both proteins which are shown to elicit various strong intermolecular interactions and thus favour binding affinity. Also, binding orientation of the ligand at the protein binding cavities allowed for important hydrophobic interactions which resulted in high binding free energy of -42.50 kcal/mol and -51.64 kcal/mol towards BRD4 and PLK1, respectively. While van der Waals interactions are very important to ligand binding in BRD4-WNY complex, electrostatic interactions are pertinent to PLK1-WNY complex. Intriguingly, WNY0824 triggered conformational alterations in both proteins through increased structural instability, decreased structural compactness and mitigation in exposure of residues to solvent surface area. Consequently, critical interactions peculiar to the oncogenic activities of BRD4 and PLK1 were inhibited, a phenomenon that results in an antagonism of CRPC progression. The mechanistic insights presented in this report would further assist in the structure-based design of improved inhibitors useful in CRPC therapy.