Improving the inhibition of β-amyloid aggregation by withanolide and withanoside derivatives

Withanolides production by the endophytic fungus Penicillium oxalicum associated with Withania somnifera (L.) Dunal

Withanolides are steroidal lactones with diverse bioactive potential and their production from plant sources varies with genotype, age, culture conditions, and geographical region. Endophytic fungi serve as an alternative source to produce withanolides, like their host plant, Withania somnifera (L.) Dunal. The present study aimed to isolate endophytic fungi capable of producing withanolides, characterization and investigation of biological activities of these molecules. The methanolic fungal crude extract of one of the fungal isolates WSE16 showed maximum withanolide production (219 mg/L). The fungal isolate WSE16 was identified as Penicillium oxalicum based on its morphological and internal transcribed spacer (ITS) sequence analysis and submitted in NCBI (accession number OR888725). The methanolic crude extract of P. oxalicum was further purified by column chromatography, and collected fractions were assessed for the presence of withanolides. Fractions F3 and F4 showed a higher content of withanolides (51.8 and 59.1 mg/L, respectively) than other fractions. Fractions F3 and F4 exhibited antibacterial activity against Staphylococcus aureus with an IC50 of 23.52 and 17.39 µg/ml, respectively. These fractions also showed antioxidant activity (DPPH assay with IC50 of 39.42 and 38.71 µg/ml, superoxide anion scavenging assay with IC50 of 41.10 and 38.84 µg/ml, and reducing power assay with IC50 of 42.61 and 41.40 µg/ml, respectively) and acetylcholinesterase inhibitory activity (IC50 of 30.34 and 22.05 µg/ml, respectively). The withanolides present in fraction 3 and fraction 4 were identified as (20S, 22R)-1a-Acetoxy-27-hydroxywitha-5, 24-dienolide-3b-(O-b-D-glucopyranoside) and withanamide A, respectively, using UV, FTIR, HRMS, and NMR analysis. These results suggest that P. oxalicum, an endophytic fungus isolated from W. somnifera, is a potential source for producing bioactive withanolides.

Withania somnifera (L.) Dunal, a Potential Source of Phytochemicals for Treating Neurodegenerative Diseases: A Systematic Review

Withania somnifera (L.) Dunal is a medicinal plant belonging to the traditional Indian medical system, showing various therapeutic effects such as anti-cancer, anti-inflammatory, anti-microbial, anti-diabetic, and hepatoprotective activity. Of great interest is W. somnifera's potential beneficial effect against neurodegenerative diseases, since the authorized medicinal treatments can only delay disease progression and provide symptomatic relief and are not without side effects. A systematic search of PubMed and Scopus databases was performed to identify preclinical and clinical studies focusing on the applications of W. somnifera in preventing neurodegenerative diseases. Only English articles and those containing the keywords (Withania somnifera AND "neurodegenerative diseases", "neuroprotective effects", "Huntington", "Parkinson", "Alzheimer", "Amyotrophic Lateral Sclerosis", "neurological disorders") in the title or abstract were considered. Reviews, editorials, letters, meta-analyses, conference papers, short surveys, and book chapters were not considered. Selected articles were grouped by pathologies and summarized, considering the mechanism of action. The quality assessment and the risk of bias were performed using the Cochrane Handbook for Systematic Reviews of Interventions checklist. This review uses a systematic approach to summarize the results from 60 investigations to highlight the potential role of W. somnifera and its specialized metabolites in treating or preventing neurodegenerative diseases.

Neuroprotection by Polyherbal Medicine Divya-Medha-Vati Against Scopolamine-Induced Cognitive Impairment Through Modulation of Oxidative Stress, Acetylcholine Activity, and Cell Signaling

Alzheimer disease is associated with cognitive impairments and neuronal damages. In this study, Scopolamine, a model drug used for the generation of Alzheimer-like symptoms induced cognitive dysfunction in C57BL/6 mice. It also elevated acetylcholine esterase (AcHE) activity, and reduced antioxidant (superoxide dismutase and catalase) activity in cortex tissue. Scop reduced neuronal density and increased pyknotic neurons in hippocampus tissue. In mouse neuroblastoma (Neuro2a) cells, Scop triggered a dose-dependent loss of cell viability and neurite outgrowth reduction. Scop-treated Neuro2a cells showed oxidative stress and reduction in mRNA expression for brain-derived neurotrophic factor (BDNF), nerve growth factor-1 (NGF-1), and Synapsin-1 (SYN-1) genes. Mice treated with Divya-Medha-Vati (DMV), an Ayurvedic polyherbal medicine showed protection against Scop-induced cognitive impairment (Morris Water Maze Escape Latency, and Elevated Plus Maze Transfer Latency). DMV protected against Scop-induced AcHE activity, and loss of antioxidant activities in the mice brain cortex while sustaining neuronal density in the hippocampus region. In the Neuro2a cells, DMV reduced Scop-induced loss of cell viability and neurite outgrowth loss. DMV protected the cells against induction of oxidative stress and promoted mRNA expression of BDNF, NGF-1, and SYN-1 genes. Phytochemical profiling of DMV showed the presence of Withanolide A, Withanolide B, Bacopaside II, Jujubogenin, Apigenin, Gallic acid, Caffeic acid, and Quercetin that are associated with antioxidant and neurostimulatory activities. In conclusion, the study showed that Divya-Medha-Vati was capable of promoting neuronal health and inhibiting Alzheimer-like cognitive dysfunction through enhanced antioxidant activities and modulation of neuronal activities.

Computational investigation of Moringa oleifera phytochemicals targeting EGFR: molecular docking, molecular dynamics simulation and density functional theory studies

Epidermal growth factor receptor (EGFR) is a prominent target for anticancer therapy due to its role in activating several cell signaling cascades. Clinically approved EGFR inhibitors are reported to show treatment resistance and toxicity, this study, therefore, investigates Moringa oleifera phytochemicals to find potent and safe anti-EGFR compounds. For that, phytochemicals were screened based on drug-likeness and molecular docking analysis followed by molecular dynamics simulation, density functional theory analysis and ADMET analysis to identify the effective inhibitors of EGFR tyrosine kinase (EGFR-TK) domain. Known EGFR-TK inhibitors (1-4 generations) were used as control. Among 146 phytochemicals, 136 compounds showed drug-likeness, of which Delta 7-Avenasterol was the most potential EGFR-TK inhibitor with a binding energy of -9.2 kcal/mol followed by 24-Methylenecholesterol (-9.1 kcal/mol), Campesterol (-9.0 kcal/mol) and Ellagic acid (-9.0 kcal/mol). In comparison, the highest binding affinity from control drugs was displayed by Rociletinib (-9.0 kcal/mol). The molecular dynamics simulation (100 ns) exhibited the structural stability of native EGFR-TK and protein-inhibitor complexes. Further, MM/PBSA computed the binding free energies of protein complex with Delta 7-Avenasterol, 24-Methylenecholesterol, Campesterol and Ellagic acid as -154.559 ± 18.591 kJ/mol, -139.176 ± 19.236 kJ/mol, -136.212 ± 17.598 kJ/mol and -139.513 ± 23.832 kJ/mol, respectively. Non-polar interactions were the major contributors to these energies. The density functional theory analysis also established the stability of these inhibitor compounds. ADMET analysis depicted acceptable outcomes for all top phytochemicals without displaying any toxicity. In conclusion, this report has identified promising EGFR-TK inhibitors to treat several cancers that can be further investigated through laboratory and clinical tests.

A blend of Withania somnifera (L.) Dunal root and Abelmoschus esculentus (L.) Moench fruit extracts relieves constipation and improves bowel function: A proof-of-concept clinical investigation

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal (WS) and Abelmoschus esculentus (L.) Moench (AE) are known as Ashwagandha and Okra, respectively, important herbs in traditional medicine for their diverse therapeutic values. WS root is an adaptogen that relieves stress and anxiety and promotes sleep. AE fruit or Okra is widely consumed as a vegetable and is traditionally used to treat diabetes, gastric irritations, ulcers, and obesity.

AIM OF THE STUDY

The present randomized, double-blind, placebo-controlled study aimed to establish a proof-of-concept evaluating the efficacy and tolerability of a proprietary blend of standardized extracts of WS root and AE fruit, CL18100F4 in relieving constipation and improving quality of life in adults.

MATERIALS AND METHODS

Forty-eight male and female participants (age: 25-60 years) with functional constipation (following Rome-III criteria) were randomized into placebo, 300 or 500 mg of CL18100F4 groups, and supplemented for fourteen consecutive days.

RESULTS

CL18100F4 supplementation significantly (p < 0.0001) reduced the Patient Assessment of Constipation-Symptoms (PAC-SYM), Patient Assessment of Constipation-Quality of Life (PAC-QOL), and Gastrointestinal Symptom Rating Scale (GSRS) scores. CL18100F4 supplementation improved sleep quality and reduced stress (p < 0.0001). At the end of the study, CL18100F4-500 subjects showed significant increases in serum serotonin, gastrin, and interleukin-10 and decrease in interleukin-6 and cortisol levels. Participants' hematology, total blood chemistry, vital signs, and urinalysis parameters were within the normal ranges. No adverse events were reported.

CONCLUSIONS

This short-duration, single-site clinical investigation demonstrates that CL18100F4 supplementation is tolerable, helps relieve constipation, reduces stress, and improves gastrointestinal function, sleep quality, and general wellness in adults.

TRIAL REGISTRATION

Clinical Trials Registry- India (CTRI/2020/11/029320); Registered on 24/11/2020. Available at: http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=49391&EncHid=&userName=CL18100F4.

Development of quinazolinone and vanillin acrylamide hybrids as multi-target directed ligands against Alzheimer's disease and mechanistic insights into their binding with acetylcholinesterase

In view of Multi-Target Directed Ligand (MTDL) approach in treating Alzheimer's Disease (AD), a series of novel quinazolinone and vanillin cyanoacetamide based acrylamide derivatives (9a-z) were designed, synthesized, and assessed for their activity against a panel of selected AD targets including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), amyloid β protein (Aβ), and also 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and neuroprotective activities. Five of the target analogs 9e, 9h, 9 l, 9t and 9z showed elevated AChE inhibitory activity with IC50 values of 1.058 ± 0.06, 1.362 ± 0.09, 1.434 ± 0.10, 1.015 ± 0.10, 1.035 ± 0.02 µM respectively, high inhibition selectivity against AChE over BChE and good DPPH radical scavenging activity. Enzyme kinetic studies of the potent hybrids in the series disclosed their mixed inhibition approach. Active analogs were found to be non-toxic on SK-N-SH cell lines and have excellent neuroprotective effects against H2O2-induced cell death. Strong modulating affinities on Aβ aggregation process were observed for most active compounds since; they irretrievably interrupted the morphology of Aβ42 fibrils, increased the aggregates and declined the Aβ-induced toxicity in neurons. From the fluorescence emission studies, the binding constants (K) were determined as 2.5 ± 0.021x103, 2.7 ± 0.015x103, 3.7 ± 0.020x103, 2.4 ± 0.013x104, and 5.0 ± 0.033x103 M-1 and binding free energies as -5.82 ± 0.033, -6.07 ± 0.042, -6.26 ± 0.015, -7.71 ± 0.024, and -6.29 ± 0.026 kcal M-1 for complexes of AChE-9e, 9h, 9 l, 9t and 9z, respectively. Moreover, the CD analysis inferred the limited modifications in the AChE secondary structure when it binds to 9e, 9h, 9 l, 9t and 9z. On the basis of docking studies against AChE, the most active congeners were well oriented in the enzyme's active site by interacting with both catalytic active site (CAS) and peripheral anionic site (PAS). In summary, these quinazolinone and vanillin acrylamide hybrid analogs can be used as promising molecular template to further explore their in vivo efficiency in the development of lead compound to treat AD.Communicated by Ramaswamy H. Sarma.

Synthetic and Natural Bioactive Molecules in Balancing the Crosstalk among Common Signaling Pathways in Alzheimer's Disease: Understanding the Neurotoxic Mechanisms for Therapeutic Intervention

The structure and function of the brain greatly rely on different signaling pathways. The wide variety of biological processes, including neurogenesis, axonal remodeling, the development and maintenance of pre- and postsynaptic terminals, and excitatory synaptic transmission, depends on combined actions of these molecular pathways. From that point of view, it is important to investigate signaling pathways and their crosstalk in order to better understand the formation of toxic proteins during neurodegeneration. With recent discoveries, it is established that the modulation of several pathological events in Alzheimer's disease (AD) due to the mammalian target of rapamycin (mTOR), Wnt signaling, 5'-adenosine monophosphate activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), and sirtuin 1 (Sirt1, silent mating-type information regulator 2 homologue 1) are central to the key findings. These include decreased amyloid formation and inflammation, mitochondrial dynamics control, and enhanced neural stability. This review intends to emphasize the importance of these signaling pathways, which collectively determine the fate of neurons in AD in several ways. This review will also focus on the role of novel synthetic and natural bioactive molecules in balancing the intricate crosstalk among different pathways in order to prolong the longevity of AD patients.

Ashwagandha (Withania somnifera)—Current Research on the Health-Promoting Activities: A Narrative Review

In recent years, there has been a significant surge in reports on the health-promoting benefits of winter cherry (Withania somnifera), also known as Ashwagandha. Its current research covers many aspects of human health, including neuroprotective, sedative and adaptogenic effects and effects on sleep. There are also reports of anti-inflammatory, antimicrobial, cardioprotective and anti-diabetic properties. Furthermore, there are reports of reproductive outcomes and tarcicidal hormone action. This growing body of research on Ashwagandha highlights its potential as a valuable natural remedy for many health concerns. This narrative review delves into the most recent findings and provides a comprehensive overview of the current understanding of ashwagandha’s potential uses and any known safety concerns and contraindications.

Discovery of New 1,3,4-Oxadiazoles with Dual Activity Targeting the Cholinergic Pathway as Effective Anti-Alzheimer Agents

Finding an effective anti-Alzheimer agent is quite challenging due to its multifactorial nature. As such, multitarget directed ligands (MTDLs) could be a promising paradigm for finding potential therapeutically effective new small-molecule bioactive agents against Alzheimer's disease (AD). We herein present the design, synthesis, and biological evaluation of a new series of compounds based on a 5-pyrid-3-yl-1,3,4-oxadiazole scaffold. Our synthesized compounds displayed excellent in vitro enzyme inhibitory activity at nanomolar (nM) concentrations against two major AD disease-modifying targets, i.e., acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among our compounds, 5e was considered the best dual inhibitor of both AChE (IC₅₀ = 50.87 nM) and BuChE (IC₅₀ = 4.77 nM), where these values surpassed those of rivastagmine (the only FDA-approved dual AChE and BuChE inhibitor) in our study. Furthermore, in vivo and ex vivo testing of the hit compound 5e highlighted its significant AD-biotargeting effects including reducing the elevated levels of lipid peroxidation and glutathione (GSH), normalizing levels of 8-OHdG, and, most importantly, decreasing the levels of the well-known AD hallmark β-amyloid protein. Finally, the binding ability of 5e to each of our targets, AChE and BuChE, was confirmed through additional molecular docking and molecular dynamics (MD) simulations that reflected good interactions of 5e to the active site of both targets. Hence, we herein present a series of new 1,3,4-oxadiazoles that are promising leads for the development of dual-acting AChE and BuChE inhibitors for the management of AD.

Engineering of Saccharomyces cerevisiae for 24-Methylene-Cholesterol Production

24-Methylene-cholesterol is a necessary substrate for the biosynthesis of physalin and withanolide, which show promising anticancer activities. It is difficult and costly to prepare 24-methylene-cholesterol via total chemical synthesis. In this study, we engineered the biosynthesis of 24-methylene-cholesterol in Saccharomyces cerevisiae by disrupting the two enzymes (i.e., ERG4 and ERG5) in the yeast’s native ergosterol pathway, with ERG5 being replaced with the DHCR7 (7-dehydrocholesterol reductase) enzyme. Three versions of DHCR7 originating from different organisms—including the DHCR7 from Physalis angulata (PhDHCR7) newly discovered in this study, as well as the previously reported OsDHCR7 from Oryza sativa and XlDHCR7 from Xenopus laevis—were assessed for their ability to produce 24-methylene-cholesterol. XlDHCR7 showed the best performance, producing 178 mg/L of 24-methylene-cholesterol via flask-shake cultivation. The yield could be increased up to 225 mg/L, when one additional copy of the XlDHCR7 expression cassette was integrated into the yeast genome. The 24-methylene-cholesterol-producing strain obtained in this study could serve as a platform for characterizing the downstream enzymes involved in the biosynthesis of physalin or withanolide, given that 24-methylene-cholesterol is a common precursor of these chemicals.

Deciphering the AChE-binding mechanism with multifunctional tricyclic coumarin anti-Alzheimer's agents using biophysical and bioinformatics approaches and evaluation of their modulating effect on Amyloidogenic peptide assembly

Investigating the drug-AChE binding mechanism is vital in understanding its cogent use in medical practice against Alzheimer's disease (AD). The production and accumulation of oligomers of β-amyloid is a central event in the neuropathology of AD. Beside the inhibition of assembly process, modulation of the aggregation process of these proteins towards minimally toxic pathways may be a possible therapeutic strategy for AD. Hence, the present study aims to examine the effect of multifunctional fused tricyclic 7-hydroxy 4-methyl coumarin analogs (HMC_1-5) on the self-induced aggregation of β-amyloid using Thioflavin T (ThT) assay, scanning electron microscopic study, AlamarBlue and immune blotting assays and also the binding mechanism with AChE by fluorescence emission, conformational, molecular docking and molecular dynamic simulation studies under physiological pH 7.4. The ThT assay, FE-SEM study, cell line and western blots establish that the HMC_1-5 molecules could irreversibly disrupt preformed Aβ₄₂ fibrils, accelerate the aggregates into micro size co-assembled structures, and effectively eliminate the cytotoxicity of Aβ_1-42. Fluorescence emission studies indicating a strong binding affinity between HMC_1-5 and AChE with the binding constants of 1.04 × 10⁵, 3.57 × 10⁴, 1.97 × 10⁴, 3.07 × 10⁴ and 2.95 × 10⁴ M^-1, respectively and binding sites number found to be 1. CD studies disclosed a partial unfolding in the secondary structure of AChE upon binding with HMC_1-5. Docking analysis inferred that the HMC_1-5 were bound through hydrophobic and hydrophilic interactions to the AChE active site. Molecular dynamics simulations emphasized the stability of AChE-HMC_1-5 complexes throughout the 100 ns simulations, and the local conformational changes of the residues of AChE validate the stability of complexes. These results provide new and unique complementary approach for modulating the biological effects of the Aβ aggregates by coumarin analogs and new insights for further in vivo investigations as novel anti AD agents.