Profiling withanolide A for therapeutic targets in neurodegenerative diseases

Natural compounds as therapeutic candidates for spinocerebellar ataxia type 1: a computational approach

Spinocerebellar Ataxia Type 1 (SCA1) is a progressive neurodegenerative disorder caused by the expansion and aggregation of polyglutamine (polyQ) in the Ataxin-1 (ATXN1) protein, leading to severe neuronal dysfunction. Currently, only symptomatic treatments are available, highlighting the requirement for disease-modifying therapies. This study employed a detailed in silico approach to identify potential neuroprotective natural compounds targeting the Ataxin-1 protein implicated in SCA1. The three-dimensional structure of Ataxin-1 was retrieved, validated, and optimized to achieve a stable structural model. Validation using a Ramachandran plot indicated that 77% of the residues were in favored regions, confirming the reliability of the protein structure. Active site residues were identified using CASTp, and receptor grids were generated for molecular docking studies. A library of 50 natural compounds was screened, among which 21 satisfied Lipinski's rule of five. Molecular docking using PyRx and AutoDock 4.2 identified Withanolide A as the top candidate, exhibiting the highest binding affinity (- 10.14 kcal/mol) and forming four hydrogen bonds with key active site residues. The top six ligands were further assessed for ADMET properties, with Withanolide A showing optimal drug-likeness, high gastrointestinal and blood-brain absorption, and non-toxic profiles. Molecular dynamics simulations over 200 ns demonstrated the stability of the Ataxin-1-Withanolide A complex, supported by RMSD, RMSF, RoG, and SASA analyses. PCA revealed reduced conformational flexibility, indicating enhanced structural stability of the ligand-bound complex. Additionally, MM-PBSA analysis confirmed that Van der Waals interactions were the primary stabilizing forces, complemented by electrostatic contributions. This integrated computational approach highlights the therapeutic potential of Withanolide A as a neuroprotective agent for SCA1, providing a base for future experimental validation and drug development.

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Withania somnifera-derived phytochemicals as Bcl-B inhibitors in cancer therapy: A computational approach from byte to bench to bedside

Cancer is the second foremost cause of fatalities associated with non-communicable diseases across the globe, affecting multiple organs and often necessitating costly treatments with adverse side effects. Apoptosis, the body's natural cell death process, plays a crucial role in the prevention of cancer, but it's often disrupted in cancer cells, allowing uncontrolled proliferation. Restoring apoptosis in cancer cells is one of the promising therapeutic strategies to curb tumor growth and enhance clinical outcomes. Bcl-B, an anti-apoptotic protein within the Bcl-2 family, interacts with Bax to mitigate apoptosis, indicating it as a druggable target for cancer therapy. There's a critical need for natural, cost-effective alternatives with minimal adverse effects to reduce morbidity rates of cancer patients. Plant-based immunoprotective medications, particularly from sustainable sources like known medicinal plants, offer substantial potential for cancer treatment. This study involves comprehensive in silico approaches (byte) to evaluate the inhibition potential of the phytochemicals derived from Withania somnifera against the anti-apoptotic Bcl-B protein. Research into Bcl-B's binding affinity with 80 phytochemicals from this plant aims to identify interaction sites for promising anticancer agents. This study's focus on Bcl-B protein highlights its potential in modulating apoptotic pathways and exploring novel anti-cancer therapeutics. Through comprehensive screening based on drug-likeness and pharmacokinetic properties, combined with in-house virtual screening, molecular docking, molecular dynamics simulations, and MM/PBSA-based binding free energy analysis, three promising candidate inhibitors-Withanolide L (IMPHY009438), Withanolide M (IMPHY003143), and Withanolide A (IMPHY000090)-were identified and prioritized. These candidates showed favorable estimated binding free energy values, along with desirable drug-likeness and pharmacokinetic profiles. The results demonstrated that the selected and prioritized phytochemicals, Withanolide L, Withanolide M, and Withanolide A display comparable efficacy to Obatoclax (CID: 11404337) and other known synthetic, semi-synthetic, and natural inhibitors of Bcl-2 family proteins. These findings establish a strong bench foundation for further experimental validation and bedside application, potentially offering an alternative natural approach to cancer therapy.

The total withanolides from the leaves of Datura stramonium L. Improves Alzheimer's disease pathology by restraining neuroinflammation through NLRP3/IL-1β/IL1R1/TOM 1 pathway

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the deposition of beta-amyloid (Aβ) peptides. Microglia-mediated neuroinflammation is one of the primary contributors to the pathogenesis of AD. Withanolides, the main constituents in the leaves of Datura stramonium L., exhibit anti-neuroinflammatory activity. It is unknown if total withanolide from Datura stramonium L. leaves (TWD) reduces nerve inflammation and potentially mitigates the pathogenic elements of AD. This study examined the potential effects of TWD on neuroinflammation in triple transgenic AD (3 × Tg-AD) mice and LPS-induced BV-2, as well as associated signaling pathways. HPLC-Q-TOF-MS/MS was used in this study to examine the main chemical components of the TWD extract. 3 × Tg-AD as in vivo AD models and LPS induce BV-2 cells in vitro AD models. The molecular process was investigated by ELISA, WB, IHC, and IF. In 3 × Tg-AD mice, TWD dramatically ameliorates cognitive impairment. Treatment with TWD can counteract the increased activation of microglia and Aβ deposits observed in 3 × Tg-AD mice. Further research indicates that TWD can enhance TOM 1 and mitigate inflammatory responses by reducing the levels of IL-1β, TNF-α, IL-6, IL1R1, and IL-18. Additionally, TWD may inhibit neuroinflammation through the pathways of IL1R1/MyD88/NF-κB and NLRP3/IL-1β/IL1R1. In summary, this study reveals for the first time that TWD effectively improves cognitive deficits in 3 × Tg-AD mice by modulating the IL1R1/MyD88/NF-κB and NLRP3/IL-1β/IL1R1 pathways. It also alleviates excessive activation of microglia and suppresses Aβ accumulation. Therefore, TWD has the potential as a therapeutic agent for AD.

In silico evaluation of pharmacokinetics properties of withanolides and simulation of their biological activities against Alzheimer's disease

The withanolides are naturally occurring steroidal lactones found mainly in plants of the Solanaceae family. The subtribe Withaninae includes species like Withania sominifera, which are a source of many bioactive withanolides. In this work, we selected and evaluate the ADMET-related properties of 91 withanolides found in species of the subtribe Withaninae computationally, to predict the relationship between their structures and their pharmacokinetic profiles. We also evaluated the interaction of these withanolides with known targets of Alzheimer's disease (AD) through molecular docking and molecular dynamics. Withanolides presented favorable pharmacokinetic properties, like high gastrointestinal absorption, lipophilicity (logP ≤ 5), good distribution and excretion parameters, and a favorable toxicity profile. The specie Withania aristata stood out as an interesting source of the promising withanolides classified as 5-ene with 16-ene or 17-ene. These withanolides presented a favourable pharmacokinetic profile and were also highlighted as the best candidates for inhibition of AD-related targets. Our results also suggest that withanolides are likely to act as cholinesterase inhibitors by interacting with the catalytic pocket in an energy favorable and stable way.Communicated by Ramaswamy H. Sarma.

Effects of Withania somnifera on Cortisol Levels in Stressed Human Subjects: A Systematic Review

BACKGROUND

Withania somnifera (WS), a popular medicinal plant of the Solanaceae family, contains active ingredients with antioxidant, anti-inflammatory, immunomodulatory, and anti-stress activities. However, its precise mechanisms of action and optimal use as a supplement are not yet fully understood. The objective of this systematic review is to assess the impact of WS supplementation on cortisol levels in stressed humans by analyzing clinical trials conducted prior to May 2023.

METHODS

The assessment was carried out following the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) by exploring the databases of EMBASE, PubMed, Google Scholar, CENTRAL, and Scopus.

RESULTS

Of the 4788 articles identified, only 9 studies met the selection criteria. The selected studies varied in terms of design, results, formulations, dosages, and treatment duration (30-112 days), and involved subjects with varying degrees of stress. WS supplementation decreases cortisol secretion with no significant adverse effects. Nonetheless, none of the studies evaluated the potential impact of cortisol reduction on adrenal function and long-term effects.

CONCLUSIONS

Brief-term supplementation with WS appears to have a stress-reducing effect in stressed individuals. However, since the long-term effects of WS supplementation are not yet fully understood, WS supplements should be used under medical supervision.

Anti-inflammatory withajardins from the leaves of Athenaea velutina

Withajardins, uncommon modified withanolide-type steroids, have been isolated exclusively from plants of the Solanaceae family so far. Two undescribed withajardins and the known tuboanosigenin were isolated from the hexane/EtOAc 1:1 extract from Athenaea velutina leaves. Their structures were established by an extensive analysis of 1D and 2D-NMR and HRMS data. The absolute configuration was determined by X-ray diffraction (withajardin L and tuboanosigenin) and circular dichroism (CD) analyses (withajardin M). The anti-inflammatory activity of compounds was evaluated through the inhibition of the lipopolysaccharide (LPS)-induced nitric oxide (NO), TNF-α, and IL-6 release in RAW264.7 cells. The cell viability effects to RAW 264.7 cells showed IC₅₀ values of 74.4-354.4 μM. The compounds attenuated LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 in RAW264.7 cells.

Withaphysalins from Medicinal and Edible Physalis minima and Their Anti-inflammatory Activities

Physalis minima is a medicinal and edible plant in China. In this study, 22 new withaphysalins, including a novel 1(10 → 6)abeo-14β-hydroxy one (1) and other 15 unusual 14β-hydroxy ones (3-4, 6-17, 19), were isolated from the whole herbs of P. minima together with two known analogues (23-24). Their structures were established by extensive analysis of high-resolution electrospray ionization mass spectrometry, IR, and 1D and 2D NMR spectroscopic data. Their absolute configurations were determined by electronic circular dichroism (ECD) spectra and single-crystal X-ray crystallographic analyses, together with DFT NMR calculations. All isolated compounds were evaluated for their anti-inflammatory activity via measuring the colorimetric reporter of the secreted embryonic alkaline phosphatase gene driven by an IFN-β minimal promoter fused to five copies of the NF-κB consensus transcriptional response element and three copies of the c-Rel binding site in LPS-stimulated human THP1-Dual cells. Compounds 2, 5, 6, 9, 10, 11, and 20 showed significant anti-inflammatory effects with IC₅₀ values in the range of 3.01-13.39 μM. Among them, compounds 2 and 10 showed better anti-inflammatory effects to inhibit the secretion of IL-6, IL-1β, and TNF-α in LPS-stimulated THP1-Dual cells.

Effect of Withanolide A on 7-Ketocholesterol Induced Cytotoxicity in hCMEC/D3 Brain Endothelial Cells

Withanolide A is a naturally occurring phytochemical that is found in Ashwagandha (Withania somnifera, fam. Solanaceae) or Indian Ginseng. In the current study, we elucidated the effect of withanolide A on 7-ketocholesterol (7KC) induced injury in hCMEC/D3 human brain endothelial cells. 7KC is a cholesterol oxidation product or oxysterol that is present in atherosclerotic plaques and is elevated in the plasma of patients with hypercholesterolemia and/or diabetes mellitus. Results showed that withanolide A significantly reduced the effects of 7KC, which include loss of endothelial cell viability, increase in expression of pro-inflammatory genes-IL-1β, IL-6, IL-8, TNF-α, cyclooxygenase-2 (COX-2), increased COX-2 enzyme activity, increased ROS formation, increased expression of inducible nitric oxide synthase and genes associated with blood clotting, including Factor 2/thrombin, Factor 8, von Willebrand factor, and thromboxane A synthase, and increased human thrombin enzyme activity. Some of the above effects of withanolide A on 7KC were reduced in the presence of the glucocorticoid receptor antagonist, mifepristone (RU486). These findings suggest that the glucocorticoid receptor could play a role in the cytoprotective, antioxidant, and anti-clotting effects of withanolide A against 7KC. Further studies are necessary to elucidate the detailed mechanisms of action of withanolide A against oxysterol-induced injury.

Natural withanolides, an update

Covering: March 2010 to December 2020. Previous review: Nat. Prod. Rep., 2011, 28, 705This review summarizes the latest progress and perspectives on the structural classification, biological activities and mechanisms, metabolism and pharmacokinetic investigations, biosynthesis, chemical synthesis and structural modifications, as well as future research directions of the promising natural withanolides. The literature from March 2010 to December 2020 is reviewed, and 287 references are cited.

Contemporary advancements in the semi-synthesis of bioactive terpenoids and steroids

Many natural products have intriguing biological properties that arise from their fascinating chemical structures. However, the intrinsic complexity of the structural skeleton and the reactive functional groups on natural products pose tremendous challenges to chemical syntheses. Semi-synthesis uses chemical compounds isolated from natural sources as the starting materials to produce other novel compounds with distinct chemical and medicinal properties. In particular, advancements in various types of sp3 C-H bond functionalization reactions and skeletal rearrangement methods have contributed to the re-emergence of semi-synthesis as an efficient approach for the synthesis of structurally complex bioactive natural products. Here, we begin with a brief discussion of several bioactive natural products that were obtained via a semi-synthetic approach between 2008 and 2015 and we then discuss in-depth contemporary advancements in the semi-synthesis of bioactive terpenoids and steroids reported during 2016-2020.

Induction of stress resistance and extension of lifespan in Chaenorhabditis elegans serotonin-receptor knockout strains by withanolide A

INTRODUCTION

Approximately 300 million people worldwide suffer from depression. The COVID-19 crisis may dramatically increase these numbers. Severe side effects and resistance development limit the use of standard antidepressants. The steroidal lactone withanolide A (WA) from Withania somnifera may be a promising alternative. Caenorhabditis elegans was used as model to explore WA's anti-depressive and anti-stress potential.

METHODS

C. elegans wildtype (N2) and deficient strains (AQ866, DA1814, DA2100, DA2109 and MT9772) were used to assess oxidative, osmotic or heat stress as measured by generation of reactive oxygen species (ROS), determination of lifespan, and mRNA expression of serotonin receptor (ser-1, ser-4, ser-7) and serotonin transporter genes (mod-5). The protective effect of WA was compared to fluoxetine as clinically established antidepressant. Additionally, WA's effect on lifespan was determined. Furthermore, the binding affinities and pKi values of WA, fluoxetine and serotonin as natural ligand to Ser-1, Ser-4, Ser-7, Mod-5 and their human orthologues proteins were calculated by molecular docking.

RESULTS

Baseline oxidative stress was higher in deficient than wildtype worms. WA and fluoxetine reduced ROS levels in all strains except MT9772. WA and fluoxetine prolonged survival times in wildtype and mutants under osmotic stress. WA but not fluoxetine increased lifespan of all heat-stressed C. elegans strains except DA2100. Furthermore, WA but not fluoxetine extended lifespan in all non-stressed C. elegans strains. WA also induced mRNA expression of serotonin receptors and transporters in wildtype and mutants. WA bound with higher affinity and lower pKi values to all C. elegans and human serotonin receptors and transporters than serotonin, indicating that WA may competitively displaced serotonin from the binding pockets of these proteins.

CONCLUSION

WA reduced stress and increased lifespan by ROS scavenging and interference with the serotonin system. Hence, WA may serve as promising candidate to treat depression.

Recent advances in identifying protein targets in drug discovery

Phenotype-based screening has emerged as an alternative route for discovering new chemical entities toward first-in-class therapeutics. However, clarifying their mode of action has been a significant bottleneck for drug discovery. For target protein identification, conventionally bioactive small molecules are conjugated onto solid supports and then applied to isolate target proteins from whole proteome. This approach requires a high binding affinity between bioactive small molecules and their target proteins. Besides, the binding affinity can be significantly hampered after structural modifications of bioactive molecules with linkers. To overcome these limitations, two major strategies have recently been pursued: (1) the covalent conjugation between small molecules and target proteins using photoactivatable moieties or electrophiles, and (2) label-free target identification through monitoring target engagement by tracking the thermal, proteolytic, or chemical stability of target proteins. This review focuses on recent advancements in target identification from covalent capturing to label-free strategies.

Natural Products and Their Bioactive Compounds: Neuroprotective Potentials against Neurodegenerative Diseases

In recent years, natural products, which originate from plants, animals, and fungi, together with their bioactive compounds have been intensively explored and studied for their therapeutic potentials for various diseases such as cardiovascular, diabetes, hypertension, reproductive, cancer, and neurodegenerative diseases. Neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis are characterized by the progressive dysfunction and loss of neuronal structure and function that resulted in the neuronal cell death. Since the multifactorial pathological mechanisms are associated with neurodegeneration, targeting multiple mechanisms of actions and neuroprotection approach, which involves preventing cell death and restoring the function to damaged neurons, could be promising strategies for the prevention and therapeutic of neurodegenerative diseases. Natural products have emerged as potential neuroprotective agents for the treatment of neurodegenerative diseases. This review focused on the therapeutic potential of natural products and their bioactive compounds to exert a neuroprotective effect on the pathologies of neurodegenerative diseases.