Binding studies and biological evaluation of β-carotene as a potential inhibitor of human calcium/calmodulin-dependent protein kinase IV

Vanillin-Isatin Hybrid-Induced MARK4 Inhibition As a Promising Therapeutic Strategy against Hepatocellular Carcinoma

Microtubule affinity-regulating kinase 4 (MARK4) is a serine-threonine kinase that phosphorylates microtubule-associated proteins (MAPs) and increases the microtubule dynamics. Due to its direct involvement in initiation, cell division, progression, and cancer metastasis, MARK4 is considered a potential therapeutic target. Here, we designed, synthesized, and characterized vanillin-isatin hybrids and evaluated their MARK4 inhibitory potential. All of the compounds strongly bind to MARK4 and interact closely with the active site residues. Finally, the compound VI-9 was selected for further investigation due to its high binding affinity and strong MARK4 inhibitory potential. Tau-phosphorylation assay has further confirmed that VI-9 significantly reduced the activity of MARK4. Compared with vanillin, VI-9 showed a better binding affinity and MARK4 inhibitory potential. Cell viability assays on human hepatocellular carcinoma (HCC) cell lines C3A and SNU-475 revealed that VI-9 inhibited their growth and proliferation. In addition, these compounds were nontoxic (up to 200 μM) for noncancerous (HEK-293) cells. Interestingly, VI-9 induces apoptosis and decreases the metastatic potential of the C3A and SNU-475 cell lines. The present work opens a newer avenue for vanillin-isatin hybrids and their derivatives in developing MARK4-targeted anticancer therapies.

Identification of potential inhibitors of tropomyosin receptor kinase B targeting CNS-related disorders and cancers

Tropomyosin receptor kinase B (TrkB), also known as neurotrophic tyrosine kinase receptor type 2 (NTRK2), is a protein that belongs to the family of receptor tyrosine kinases (RTKs). NTRK2 plays a crucial role in regulating the development and maturation of the central nervous system (CNS) and peripheral nervous system (PNS). Elevated TrkB expression levels observed in different pathological conditions make it a potential target for therapeutic interventions against neurological disorders, including depression, anxiety, Alzheimer's disease, Parkinson's disease, and certain types of cancer. Targeting TrkB using small molecule inhibitors is a promising strategy for the treatment of a variety of neurological disorders. In this research, a systematic virtual screening was carried out on phytoconstituents found in the IMPPAT library to identify compounds potentially inhibiting TrkB. The retrieved compounds from the IMPPAT library were first filtered using Lipinski's rule of five. The compounds were then sorted based on their docking score and ligand efficiency. In addition, PAINS, ADMET, and PASS evaluations were carried out for selecting drug-like compounds. Finally, in interaction analysis, we found two phytoconstituents, Wedelolactone and 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (DMCA), which possessed considerable docking scores and specificity on the TrkB ATP-binding pocket. The selected compounds were further assessed employing molecular dynamics (MD) simulations and essential dynamics. The results revealed that the elucidated compounds bind well with the TrkB binding pocket and lead to fewer conformations fluctuations. This study highlighted using phytoconstituents, Wedelolactone and DMCA as starting leads in developing novel TrkB inhibitors.Communicated by Ramaswamy H. Sarma.

Harnessing memantine in Alzheimer's disease therapy through inhibition of microtubule affinity-regulating kinase: Mechanistic insights

Alzheimer's disease (AD) is one of the neurodegenerative disorder that primarily affects memory, thinking, and behavior, eventually leading to severe cognitive impairment. Therapeutic management of AD is urgently needed to improve the quality and lifestyle of patients. Tau phosphorylating kinases are considered attractive therapeutic targets. Microtubule affinity-regulating kinase 4 (MARK4) is directly linked with pathological phosphorylations of tau, highlighting its role in the therapeutic targeting of AD. The current manuscript shows the MARK4 inhibitory effect of Memantine (MEM), a drug used in treating AD. We have performed fluorescence based binding measurements, enzyme inhibition assay, docking and molecular dynamics (MD) simulations to understand the binding of of MARK4 and MEM and subsequent inhibition in the kinase activity. A 100 ns MD simulations provided a detailed analysis of MARK4-MEM complex and the role of potential critical residues in the binding. Finally, this study provides molecular insights into the therapeutic implication of MEM in AD therapeutics. We propose MEM effectively inhibits MARK4, it may be implicated in the development of targeted and efficient treatments for AD.

Investigating the role of thymol as a promising inhibitor of pyruvate dehydrogenase kinase 3 for targeted cancer therapy

Protein kinases have emerged as major contributors to various diseases. They are currently exploited as a potential target in drug discovery because they play crucial roles in cell signaling, growth, and regulation. Their dysregulation is associated with inflammatory disorders, cancer, and neurodegenerative diseases. Pyruvate dehydrogenase kinase 3 (PDK3) has become an attractive drug target in cancer therapeutics. In the present study, we investigated the effective role of thymol in PDK3 inhibition due to the high affinity predicted through molecular docking studies. Hence, to better understand this inhibition mechanism, we carried out a 100 ns molecular dynamics (MD) simulation to analyse the dynamics and stability of the PDK3-thymol complex. The PDK3-thymol complex was stable and energetically favourable, with many intramolecular hydrogen bond interactions in the PDK3-thymol complex. Enzyme inhibition assay showed significant inhibition of PDK3 by thymol, revealing potential inhibitory action of thymol towards PDK3 (IC50 = 2.66 μM). In summary, we established thymol as one of the potential inhibitors of PDK3, proposing promising therapeutic implications for severe diseases associated with PDK3 dysregulation. This study further advances our understanding of thymol's therapeutic capabilities and potential role in cancer treatment.

An ensemble docking-based virtual screening and molecular dynamics simulation of phytochemical compounds from Malaysian Kelulut Honey (KH) against SARS-CoV-2 target enzyme, human angiotensin-converting enzyme 2 (ACE-2)

The human angiotensin-converting enzyme 2 (ACE-2) receptor is a metalloenzyme that plays an important role in regulating blood pressure by modulating angiotensin II. This receptor facilitates SARS-CoV-2 entry into human cells via receptor-mediated endocytosis, causing the global COVID-19 pandemic and a major health crisis. Kelulut honey (KH), one of Malaysian honey recently gained attention for its distinct flavour and taste while having many nutritional and medicinal properties. Recent study demonstrates the antiviral potential of KH against SARS-CoV-2 by inhibiting ACE-2 in vitro, but the bioactive compound pertaining to the ACE-2 inhibition is yet unknown. An ensemble docking-based virtual screening was employed to screen the phytochemical compounds from KH with high binding affinity against the 10 best representative structures of ACE-2 that mostly formed from MD simulation. From 110 phytochemicals previously identified in KH, 27 compounds passed the ADMET analysis and proceeded to docking. Among the docked compound, SDC and FMN consistently exhibited strong binding to ACE-2's active site (-9.719 and -9.473 kcal/mol) and allosteric site (-7.305 and -7.464 kcal/mol) as compared to potent ACE-2 inhibitor, MLN 4760. Detailed trajectory analysis of MD simulation showed stable binding interaction towards active and allosteric sites of ACE-2. KH's compounds show promise in inhibiting SARS-CoV-2 binding to ACE-2 receptors, indicating potential for preventive use or as a supplement to other COVID-19 treatments. Additional research is needed to confirm KH's antiviral effects and its role in SARS-CoV-2 therapy, including prophylaxis and adjuvant treatment with vaccination.Communicated by Ramaswamy H. Sarma.

Investigating potential of cholic acid, syringic acid, and mangiferin as cancer therapeutics through sphingosine kinase 1 inhibition

The signaling of sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate (S1P) regulates various diseases, including multiple sclerosis, atherosclerosis, rheumatoid arthritis, inflammation-related ailments, diabetes, and cancer. SphK1 is considered an attractive potential drug target and is extensively explored in cancer and other inflammatory diseases. In this study, we have investigated the inhibitory potential and binding affinity of SphK1 with cholic acid (CA), syringic acid (SA), and mangiferin (MF) using a combination of docking and molecular dynamics (MD) simulation studies followed by experimental measurements of binding affinity and enzyme inhibition assays. We observed these compounds bind to SphK1 with a significantly high affinity and eventually inhibit its kinase activity with IC50 values of 28.23 μM, 33.35 μM, and 57.2 μM for CA, SA, and MF, respectively. Further, the docking and 100 ns MD simulation studies showed that CA, SA, and MF bind with the active site residues of SphK1 with favorable energy and strong non-covalent interactions that might be accountable for inhibiting its kinase activity. Our finding indicates that CA, SA, and MF may be implicated in designing novel anti-cancer therapeutics with an improved affinity and lesser side effects by targeting SphK1.

Integrated virtual screening and MD simulation study to discover potential inhibitors of Lyn-kinase: targeting cancer therapy

Tyrosine-protein kinase Lyn (LynK) has emerged as one of the most attractive therapeutic targets for cancer and diabetes. In this study, we used a multistep virtual screening process of natural compounds to discover potential inhibitors of LynK from the IMPPAT database. The primary filters were based on Lipinski rules, ADMET properties, and PAINS patterns. Then, binding affinities and interaction analyses were carried out for the high-affinity selectivity of the compounds towards LynK. Eventually, two natural compounds, Glabrene and Lactupicrin, were identified with high affinity and specificity for the LynK-binding pocket. Both compounds exhibited drug-like properties, as predicted by ADMET analysis and physicochemical parameters. The molecular dynamics (MD) simulation study revealed that these compounds bind to the ATP-binding pocket of LynK and interact with functionally significant residues with stability without inducing any significant structural changes to the protein. Ultimately, the identified compounds may be regarded as promising LynK inhibitors and can be used as lead molecules in the drug development against LynK-related diseases.Communicated by Ramaswamy H. Sarma.

The Effect of Beta-Carotene on Cognitive Function: A Systematic Review

β-carotene is a powerful antioxidant and dietary precursor of vitamin A whose role in maintaining mental health and cognitive performance, either alone or in combination with other dietary compounds, has been a topic of recent research. However, its effectiveness is still unclear. This systematic review, conducted according to the PRISMA guideline and assisted by the MySLR platform, addressed this issue. A total of 16 eligible original research articles were identified. Dietary intake or β-carotene serum levels were associated with improved measures of cognitive function in 7 out of 10 epidemiological studies included. In intervention studies, β-carotene consumption alone did not promote better cognitive function in the short term, but only in a long-term intervention with a mean duration of 18 years. However, all but one intervention study suggested the beneficial effects of β-carotene supplementation at doses ranging from 6 mg to 50 mg per day in combination with a multicomplex such as vitamin E, vitamin C, zinc, or selenium for a period of 16 weeks to 20 years. Despite the current limitations, the available evidence suggests a potential association between β-carotene dietary/supplementary intake and the maintenance of cognitive function. The β-carotene most probably does not act alone but in synergy with other micronutrients.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

Investigating MARK4 inhibitory potential of Bacopaside II: Targeting Alzheimer's disease

Microtubule affinity regulating kinase (MARK4) is known to hyperphosphorylate tau protein, which subsequently causes Alzheimer's disease (AD). MARK4 is a well-validated drug target for AD; thus, we employed its structural features to discover potential inhibitors. On the other hand, complementary and alternative medicines (CAMs) have been used for the treatment of numerous diseases with little side effects. In this regard, Bacopa monnieri extracts have been extensively used to treat neurological disorders because of their neuroprotective roles. The plant extract is used as a memory enhancer and a brain tonic. Bacopaside II is a major component of Bacopa monnieri; thus, we studied its inhibitory effects and binding affinity towards the MARK4. Bacopaside II show a considerable binding affinity for MARK4 (K = 10⁷ M^-1) and inhibited kinase activity with an IC₅₀ value of 5.4 μM. To get atomistic insights into the binding mechanism, we performed Molecular dynamics (MD) simulation studies for 100 ns. Bacopaside II binds strongly to the active site pocket residues of MARK4 and a number of hydrogen bonds remain stable throughout the MD trajectory. Our findings provide the basis for the therapeutic implication of Bacopaside and its derivatives in MARK4-related neurodegenerative diseases, especially AD and neuroinflammation.

Identification of plant-based hexokinase 2 inhibitors: combined molecular docking and dynamics simulation studies

Cancer cells ferment glucose, even under aerobic conditions, following a phenomenon known as the 'Warburg effect.' Hexokinase 2 (HK2) catalyzes the crucial step of phosphorylation of glucose for subsequent utilization in glycolysis and other pathways. HK2 has been proposed as a potential therapeutic target for anti-cancer therapy because of its enhanced expression in glucose-dependent tumors. Here, we have employed structure-based virtual screening using in-house library to identify potential phytoconstituents which could inhibit the HK2 activity. The initial hits were selected based on their binding affinity towards HK2 using the molecular docking approach. Subsequently, the filters for physicochemical properties, PAINS patterns and PASS evaluation were applied to find potential hits against HK2. Finally, we have identified epigallocatechin gallate (EGCG) and quercitrin, two natural compounds with appreciable binding affinity, efficiency and specificity towards the HK2 binding pocket. Both compounds were found to be binding preferentially to the HK2 active site and showed a decent set of drug-like properties. All-atom molecular dynamics (MD) simulations for 100 ns were carried out to see the conformational dynamics, complexes stability and interaction mechanism of HK2 with EGCG and quercitrin. MD simulation results showed that HK2 forms stable protein-ligand complexes with EGCG and quercitrin with consistency throughout the trajectory. Overall, these findings suggest that EGCG and quercitrin might be further exploited as promising scaffolds in the drug development process against HK2..Communicated by Ramaswamy H. Sarma.

Nano-delivery systems for food bioactive compounds in cancer: prevention, therapy, and clinical applications

Bioactive compounds represent a broad class of dietary metabolites derived from fruits and vegetables, such as polyphenols, carotenoids and glucosinolates with potential for cancer prevention. Curcumin, resveratrol, quercetin, and β-carotene have been the most widely applied bioactive compounds in chemoprevention. Lately, many approaches to encapsulating bioactive components in nano-delivery systems have improved biomolecules' stability and targeted delivery. In this review, we critically analyze nano-delivery systems for bioactive compounds, including polymeric nanoparticles (NPs), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes, niosomes, and nanoemulsions (NEs) for potential use in cancer therapy. Efficacy studies of the nanoformulations using cancer cell lines and in vivo models and updated human clinical trials are also discussed. Nano-delivery systems were found to improve the therapeutic efficacy of bioactive molecules against various types of cancer (e.g., breast, prostate, colorectal and lung cancer) mainly due to the antiproliferation and pro-apoptotic effects of tumor cells. Furthermore, some bioactive compounds have promised combination therapy with standard chemotherapeutic agents, with increased tumor efficiency and fewer side effects. These opportunities were identified and developed to ensure more excellent safety and efficacy of novel herbal medicines enabling novel insights for designing nano-delivery systems for bioactive compounds applied in clinical cancer therapy.

Therapeutic implications and clinical manifestations of thymoquinone

Thymoquinone (TQ), a natural phytochemical predominantly found in Nigella sativa, has been investigated for its numerous health benefits. TQ showed anti-cancer, anti-oxidant, and anti-inflammatory properties, validated in various disease models. The anti-cancer potential of TQ is goverened by anti-proliferation, cell cycle arrest, apoptosis induction, ROS production, anti-metastasis and anti-angiogenesis, inhibition of cell migration and invasion action. Additionally, TQ exhibited antitumor activity via the modulation of multiple pathways and molecular targets, including Akt, ERK1/2, STAT3, and NF-κB. The present review highlighted the anticancer potential of TQ . We summarize the anti-cancer, anti-oxidant, and anti-inflammatory properties of TQ, focusing on its molecular targets and its promising action in cancer therapy. We further described the molecular mechanisms by which TQ prevents signaling pathways that mediate cancer progression, invasion, and metastasis.

Inhibiting Cyclin-Dependent Kinase 6 by Taurine: Implications in Anticancer Therapeutics

Cyclin-dependent kinase 6 (CDK6) is linked with a cyclin partner and plays a crucial role in the early stages of cancer development. It is currently a potential drug target for developing therapeutic molecules targeting cancer therapy. Here, we have identified taurine as an inhibitor of CDK6 using combined in silico and experimental studies. We performed various experiments to find the binding affinity of taurine with CDK6. Molecular docking analysis revealed critical residues of CDK6 that are involved in taurine binding. Fluorescence measurement studies showed that taurine binds to CDK6 with a significant binding affinity, with a binding constant of K = 0.7 × 10⁷ M^-1 for the CDK6-taurine complex. Enzyme inhibition assay suggested taurine as a good inhibitor of CDK6 possessing an IC₅₀ value of 4.44 μM. Isothermal titration calorimetry analysis further confirmed a spontaneous binding of taurine with CDK6 and delineated the thermodynamic parameters for the CDK6-taurine system. Altogether, this study established taurine as a CDK6 inhibitor, providing a base for using taurine and its derivatives in CDK6-associated cancer and other diseases.

Structure-guided design and development of cyclin-dependent kinase 4/6 inhibitors: A review on therapeutic implications

Cyclin-dependent kinase 6 (EC 2.7.11.22) play significant roles in numerous biological processes and triggers cell cycle events. CDK6 controlled the transcriptional regulation. A dysregulated function of CDK6 is linked with the development of progression of multiple tumor types. Thus, it is considered as an effective drug target for cancer therapy. Based on the direct roles of CDK4/6 in tumor development, numerous inhibitors developed as promising anti-cancer agents. CDK4/6 inhibitors regulate the G1 to S transition by preventing Rb phosphorylation and E2F liberation, showing potent anti-cancer activity in several tumors, including HR+/HER2- breast cancer. CDK4/6 inhibitors such as abemaciclib, palbociclib, and ribociclib, control cell cycle, provoke cell senescence, and induces tumor cell disturbance in pre-clinical studies. Here, we discuss the roles of CDK6 in cancer along with the present status of CDK4/6 inhibitors in cancer therapy. We further discussed, how structural features of CDK4/6 could be implicated in the design and development of potential anti-cancer agents. In addition, the therapeutic potential and limitations of available CDK4/6 inhibitors are described in detail. Recent pre-clinical and clinical information for CDK4/6 inhibitors are highlighted. In addition, combination of CDK4/6 inhibitors with other drugs for the therapeutic management of cancer are discussed.

Beta-carotene exerted anti-proliferative and apoptotic effect on malignant mesothelioma cells

High blood levels of β-carotene and increased intake in the diets are inversely proportional to incidence of many cancer types. Antioxidant activity of β-carotene was proposed to be related with its antitumor effect. Despite this plant derivative substance being sought in many cancer types, the effectiveness of β-carotene against malignant mesothelioma remained unclear. Therefore, the present study aims to explore the impact of β-carotene on cell viability, apoptosis, and oxidative stress in mesothelioma cells. Human mesothelioma cell SPC212 were treated with β-carotene (3.125-200 μM) for 24, 48, 72, and 96 h. Cytotoxicity was measured with the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide). Annexin-V/propidium iodide (PI) and caspase 3/7 biomarkers were used to identify apoptotic cells. Finally, the oxidative stress was evaluated with flow cytometry. The results of the measurements indicated a significant decline in viable mesothelioma cancer cell numbers upon β-carotene treatment in time- and concentration-dependent manner when compared to control cells. Furthermore, β-carotene treatment led to apoptosis induction according to both annexin V/PI and caspase 3/7 assays. Furthermore, β-carotene increased oxidative stress in SPC212 cells. These results show how β-carotene affects proliferative, apoptotic, and oxidative properties in SPC212 malignant pleural mesothelioma cells and provide useful insights into future studies.

Potential Therapeutic Implications of Caffeic Acid in Cancer Signaling: Past, Present, and Future

Caffeic acid (CA) has been present in many herbs, vegetables, and fruits. CA is a bioactive compound and exhibits various health advantages that are linked with its anti-oxidant functions and implicated in the therapy and prevention of disease progression of inflammatory diseases and cancer. The anti-tumor action of CA is attributed to its pro-oxidant and anti-oxidant properties. CA’s mechanism of action involves preventing reactive oxygen species formation, diminishing the angiogenesis of cancer cells, enhancing the tumor cells’ DNA oxidation, and repressing MMP-2 and MMP-9. CA and its derivatives have been reported to exhibit anti-carcinogenic properties against many cancer types. CA has indicated low intestinal absorption, low oral bioavailability in rats, and pitiable permeability across Caco-2 cells. In the present review, we have illustrated CA’s therapeutic potential, pharmacokinetics, and characteristics. The pharmacological effects of CA, the emphasis on in vitro and in vivo studies, and the existing challenges and prospects of CA for cancer treatment and prevention are discussed in this review.

Potential Therapeutic Implications of Caffeic Acid in Cancer Signaling: Past, Present, and Future

Caffeic acid (CA) has been present in many herbs, vegetables, and fruits. CA is a bioactive compound and exhibits various health advantages that are linked with its anti-oxidant functions and implicated in the therapy and prevention of disease progression of inflammatory diseases and cancer. The anti-tumor action of CA is attributed to its pro-oxidant and anti-oxidant properties. CA’s mechanism of action involves preventing reactive oxygen species formation, diminishing the angiogenesis of cancer cells, enhancing the tumor cells’ DNA oxidation, and repressing MMP-2 and MMP-9. CA and its derivatives have been reported to exhibit anti-carcinogenic properties against many cancer types. CA has indicated low intestinal absorption, low oral bioavailability in rats, and pitiable permeability across Caco-2 cells. In the present review, we have illustrated CA’s therapeutic potential, pharmacokinetics, and characteristics. The pharmacological effects of CA, the emphasis onin vitro and in vivostudies, and the existing challenges and prospects of CA for cancer treatment and prevention are discussed in this review.

Natural products can be used in therapeutic management of COVID-19: Probable mechanistic insights

The unexpected emergence of the new Coronavirus disease (COVID-19) has affected more than three hundred million individuals and resulted in more than five million deaths worldwide. The ongoing pandemic has underscored the urgent need for effective preventive and therapeutic measures to develop anti-viral therapy. The natural compounds possess various pharmaceutical properties and are reported as effective anti-virals. The interest to develop an anti-viral drug against the novel severe acute respiratory syndrome Coronavirus (SARS-CoV-2) from natural compounds has increased globally. Here, we investigated the anti-viral potential of selected promising natural products. Sources of data for this paper are current literature published in the context of therapeutic uses of phytoconstituents and their mechanism of action published in various reputed peer-reviewed journals. An extensive literature survey was done and data were critically analyzed to get deeper insights into the mechanism of action of a few important phytoconstituents. The consumption of natural products such as thymoquinone, quercetin, caffeic acid, ursolic acid, ellagic acid, vanillin, thymol, and rosmarinic acid could improve our immune response and thus possesses excellent therapeutic potential. This review focuses on the anti-viral functions of various phytoconstituent and alkaloids and their potential therapeutic implications against SARS-CoV-2. Our comprehensive analysis provides mechanistic insights into phytoconstituents to restrain viral infection and provide a better solution through natural, therapeutically active agents.

Comparative performance evaluation of chitosan based polymeric microspheres and nanoparticles as delivery system for bacterial β-carotene derived from Planococcus sp. TRC1

β-carotene is a natural compound with immense healthcare benefits. To overcome insolubility and lack of stability which restricts its application, in this study, β-carotene from Planococcus sp. TRC1 was entrapped into formulations of chitosan‑sodium alginate microspheres (MF1, MF2 and MF3) and chitosan nanoparticles (NF1, NF2 and NF3). The maximum entrapment efficiency (%) and loading capacity (%) were 80.6 ± 4.28 and 26 ± 3.05 (MF2) and 92.1 ± 3.44 and 41.86 ± 4.65 (NF2) respectively. Korsmeyer-Peppas model showed best fit with release, revealing non-Fickian diffusion. Thermal and UV treatment exhibited higher activation energy (kJ/mol), 17.76 and 15.57 (MF2) and 37.03 and 19.33 (NF2) compared to free β-carotene (3.7 and 3.9), uncovering enhanced stability. MF2 and NF2 revealed swelling index (%) 721 ± 1.7 and 18.1 ± 1.5 (pH 6.8) and particle size 69.5 ± 3.2 μm and 92 ± 2.5 nm respectively. FESEM, FT-IR, XRD and DSC depicted spherical morphology, intactness of functional groups and masking of crystallinity. The IC₅₀ (μg ml^-1) values for antioxidant and anticancer (A-549) activities were 33.1 ± 1.7, 45.1 ± 2.8, 39.3 ± 2.9 and 31.3 ± 1.7, 27.9 ± 2.4, 25.3 ± 2.2 for β-carotene, MF2 and NF2 respectively with no significant cytotoxicity on HEK-293 cells and RBCs (p > 0.05). This comparative study of microspheres and nanoparticles may allow the diverse applications of an unconventional bacterial β-carotene with promising stability and efficacies.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system’s response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

Discovery of Natural Compounds as Potential Inhibitors of Human Carbonic Anhydrase II: An Integrated Virtual Screening, Docking, and Molecular Dynamics Simulation Study

Carbonic anhydrase II (CAII) is one of the zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide, leading to the formation of bicarbonate and proton. CAII plays a significant role in health and disease. For example, CAII helps to maintain eye pressure while regulating the pH of the tumor microenvironment, and by extension, contributing to cancer progression. Owing to its remarkable role in cancer, visual health, and other human diseases, CAII can serve as an attractive therapeutic target. We report an original study based on high-throughput virtual screening of natural compounds from the ZINC database in search of potential inhibitors of CAII. We selected the hits based on the physicochemical, absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties, pan-assay interference compound (PAINS) patterns, and interaction analysis. Importantly, two natural compounds were identified, ZINC08918123 and ZINC00952700, bearing considerable affinity and specific interactions to the residues of the CAII-binding pocket with well-organized conformational fitting compatibility. We investigated the conformational dynamics of CAII in complex with the identified compounds through molecular dynamics simulation, which revealed the formation of a stable complex preserved throughout the 100 ns trajectories. The stability of the protein/ligand complexes is maintained by significant numbers of noncovalent interactions throughout the simulations. In conclusion, natural compounds identified in the present study specifically and computer-assisted drug design broadly offer a reliable resource and strategy to discover potential promising therapeutic inhibitors of CAII to cure various cancers and glaucoma after further experimental validation and clinical studies.

Antioxidant and Signal-Modulating Effects of Brown Seaweed-Derived Compounds against Oxidative Stress-Associated Pathology

The biological and therapeutic properties of seaweeds have already been well known. Several studies showed that among the various natural marine sources of antioxidants, seaweeds have become a potential source of antioxidants because of their bioactive compounds. Most of the metabolic diseases are caused by oxidative stress. It is very well known that antioxidants have a pivotal role in the treatment of those diseases. Recent researches have revealed the potential activity of seaweeds as complementary medicine, which have therapeutic properties for health and disease management. Among the seaweeds, brown seaweeds (Phaeophyta) and their derived bioactive substances showed excellent antioxidant properties than other seaweeds. This review focuses on brown seaweeds and their derived major bioactive compounds such as sulfated polysaccharide, polyphenol, carotenoid, and sterol antioxidant effects and molecular mechanisms in the case of the oxidative stress-originated disease. Antioxidants have a potential role in the modification of stress-induced signaling pathways along with the activation of the oxidative defensive pathways. This review would help to provide the basis for further studies to researchers on the potential antioxidant role in the field of medical health care and future drug development.

Targeting cyclin-dependent kinase 6 by vanillin inhibits proliferation of breast and lung cancer cells: Combined computational and biochemical studies

Cyclin-dependent kinase 6 (CDK6) is a member of serine/threonine kinase family, and its overexpression is associated with cancer development. Thus, it is considered as a potential drug target for anticancer therapies. This study showed the CDK6 inhibitory potential of vanillin using combined experimental and computational methods. Structure-based docking and 200 ns molecular dynamics simulation studies revealed that the binding of vanillin stabilizes the CDK6 structure and provides mechanistic insights into the binding mechanism. Enzyme inhibition and fluorescence-binding studies showed that vanillin inhibits CDK6 with an half maximal inhibitory concentration = 4.99 μM and a binding constant (K) 4.1 × 10⁷ M^-1 . Isothermal titration calorimetry measurements further complemented our observations. Studies on human cancer cell lines (MCF-7 and A549) showed that vanillin decreases cell viability and colonization properties. The protein expression studies have further revealed that vanillin reduces the CDK6 expression and induces apoptosis in the cancer cells. In conclusion, our study presents the CDK6-mediated therapeutic implications of vanillin for anticancer therapies.

Investigation of sphingosine kinase 1 inhibitory potential of cinchonine and colcemid targeting anticancer therapy

Sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate (S1P) signaling regulates numerous diseases such as cancer, diabetes, and inflammation-related ailments, rheumatoid arthritis, atherosclerosis, and multiple sclerosis. The importance of SphK1 in chemo-resistance has been extensively explored in breast, lung, colon, and hepatocellular carcinomas. SphK1 is considered an attractive drug target for the development of anticancer therapy. New drug molecules targeting the S1P signaling are required owing to its pleiotropic nature and association with multiple downstream targets. Here, we have investigated the binding affinity and SphK1 inhibitory potential of cinchonine and colcemid using a combined molecular docking and simulation studies followed by experimental analysis. These compounds bind to SphK1 with a significantly high affinity and subsequently inhibit kinase activity (IC₅₀ 7-9 μM). Further, MD simulation studies revealed that both cinchonine and colcemid bind to the residues at the active site pocket of SphK1 with several non-covalent interactions, which may be responsible for inhibiting its kinase activity. Besides, the binding of cinchonine and colcemid causes substantial conformational changes in the structure of SphK1. Taken together, cinchonine and colcemid may be implicated in designing potential drug molecules with improved affinity and specificity for SphK1 targeting anticancer therapy.Communicated by Ramaswamy H. Sarma.

Targeting Tau Hyperphosphorylation via Kinase Inhibition: Strategy to Address Alzheimer's Disease

Microtubule-associated protein tau is involved in the tubulin binding leading to microtubule stabilization in neuronal cells which is essential for stabilization of neuron cytoskeleton. The regulation of tau activity is accommodated by several kinases which phosphorylate tau protein on specific sites. In pathological conditions, abnormal activity of tau kinases such as glycogen synthase kinase-3 β (GSK3β), cyclin-dependent kinase 5 (CDK5), c-Jun N-terminal kinases (JNKs), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and microtubule affinity regulating kinase (MARK) lead to tau hyperphosphorylation. Hyperphosphorylation of tau protein leads to aggregation of tau into paired helical filaments like structures which are major constituents of neurofibrillary tangles, a hallmark of Alzheimer's disease. In this review, we discuss various tau protein kinases and their association with tau hyperphosphorylation. We also discuss various strategies and the advancements made in the area of Alzheimer's disease drug development by designing effective and specific inhibitors for such kinases using traditional in vitro/in vivo methods and state of the art in silico techniques.

Identification of high-affinity inhibitors of SARS-CoV-2 main protease: Towards the development of effective COVID-19 therapy

Coronavirus disease 2019 (COVID-19) is an infectious disease, caused by a newly emerged highly pathogenic virus called novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Targeting the main protease (Mpro, 3CLpro) of SARS-CoV-2 is an appealing approach for drug development because this enzyme plays a significant role in the viral replication and transcription. The available crystal structures of SARS-CoV-2 Mpro determined in the presence of different ligands and inhibitor-like compounds provide a platform for the quick development of selective inhibitors of SARS-CoV-2 Mpro. In this study, we utilized the structural information of co-crystallized SARS-CoV-2 Mpro for the structure-guided drug discovery of high-affinity inhibitors from the PubChem database. The screened compounds were selected on the basis of their physicochemical properties, drug-likeliness, and strength of affinity to the SARS-CoV-2 Mpro. Finally, we have identified 6-Deaminosinefungin (PubChem ID: 10428963) and UNII-O9H5KY11SV (PubChem ID: 71481120) as potential inhibitors of SARS-CoV-2 Mpro which may be further exploited in drug development to address SARS-CoV-2 pathogenesis. Both compounds are structural analogs of known antivirals, having considerable protease inhibitory potential with improved pharmacological properties. All-atom molecular dynamics simulations suggested SARS-CoV-2 Mpro in complex with these compounds is stable during the simulation period with minimal structural changes. This work provides enough evidence for further implementation of the identified compounds in the development of effective therapeutics of COVID-19.

Carotenoids in Cancer Apoptosis-The Road from Bench to Bedside and Back

An incidence and mortality of cancer are rapidly growing worldwide, especially due to heterogeneous character of the disease that is associated with irreversible impairment of cellular homeostasis and function. Targeting apoptosis, one of cancer hallmarks, represents a potent cancer treatment strategy. Carotenoids are phytochemicals represented by carotenes, xanthophylls, and derived compounds such as apocarotenoids that demonstrate a broad spectrum of anti-cancer effects involving pro-apoptotic signaling through extrinsic and intrinsic pathways. As demonstrated in preclinical oncology research, the apoptotic modulation is performed at post-genomic levels. Further, carotenoids demonstrate additive/synergistic action in combination with conventional oncostatic agents. In addition, a sensitization of tumor cells to anti-cancer conventional treatment can be achieved by carotenoids. The disadvantage of anti-cancer application of carotenoids is associated with their low solubility and, therefore, poor bioavailability. However, this deficiency can be improved by using nanotechnological approaches, solid dispersions, microemulsions or biofortification that significantly increase the anti-cancer and pro-apoptotic efficacy of carotenoids. Only limited number of studies dealing with apoptotic potential of carotenoids has been published in clinical sphere. Pro-apoptotic effects of carotenoids should be beneficial for individuals at high risk of cancer development. The article considers the utility of carotenoids in the framework of 3P medicine.

Identification of Potential Inhibitors of Calcium/Calmodulin-Dependent Protein Kinase IV from Bioactive Phytoconstituents

Calcium/calmodulin-dependent protein kinase IV (CaMKIV) is an upstream regulator of CaMKK-CaMKIV signaling cascade that activates various transcription factors, thereby regulating several cellular activities including, neuronal communication and immune response. Owing to the abnormal expression in cancer and neurodegenerative diseases, the CaMKIV has been considered a potential drug target. In the present study, we checked the binding affinity of plant-derived natural compounds viz., quercetin, ellagic acid (EA), simvastatin, capsaicin, ursolic acid, DL-α-tocopherol acetate, and limonin towards CaMKIV. Molecular docking and fluorescence binding studies showed that EA and quercetin bind to the CaMKIV with a considerable affinity in comparison to other compounds. Enzyme inhibition assay revealed that both EA and quercetin inhibit CaMKIV activity with their IC₅₀ values in the micromolar range. To get atomistic insights into the mode of interactions, inhibition mechanism, and the stability of the CaMKIV-ligand complex, a 100 ns MD simulation analysis was performed. Both EA and quercetin bind to the catalytically important residues of active site pocket of CaMKIV forming enough stabilizing interactions presumably inhibiting enzyme activity. Moreover, no significant structural change in the CaMKIV was observed upon binding of EA and quercetin. In conclusion, this study illustrates the application of phytoconstituents in the development of therapeutic molecules targeting CaMKIV having implications in cancer and neurodegenerative diseases after in vivo validation.

Ellagic Acid Controls Cell Proliferation and Induces Apoptosis in Breast Cancer Cells via Inhibition of Cyclin-Dependent Kinase 6

Cyclin-Dependent Kinase 6 (CDK6) plays an important role in cancer progression, and thus, it is considered as an attractive drug target in anticancer therapeutics. This study presents an evaluation of dietary phytochemicals, capsaicin, tocopherol, rosmarinic acid, ursolic acid, ellagic acid (EA), limonene, caffeic acid, and ferulic acid for their potential to inhibit the activity of CDK6. Molecular docking and fluorescence binding studies revealed appreciable binding affinities of these compounds to the CDK6. Among them, EA shows the highest binding affinity for CDK6, and thus a molecular dynamics simulation study of 200 ns was performed to get deeper insights into the binding mechanism and stability of the CDK6-EA complex. Fluorescence binding studies revealed that EA binds to the CDK6 with a binding constant of K = 107 M-1 and subsequently inhibits its enzyme activity with an IC50 value of 3.053 µM. Analysis of thermodynamic parameters of CDK6-EA complex formation suggested a hydrophobic interaction driven process. The treatment of EA decreases the colonization of cancer cells and induces apoptosis. Moreover, the expression of CDK6 has been downregulated in EA-treated human breast cancer cell lines. In conclusion, this study establishes EA as a potent CDK6 inhibitor that can be further evaluated in CDK6 directed anticancer therapies.

Discovery of Hordenine as a Potential Inhibitor of Pyruvate Dehydrogenase Kinase 3: Implication in Lung Cancer Therapy

Design and development of potential pyruvate dehydrogenase kinase 3 (PDK3) inhibitors have gained attention because of their possible therapeutic uses in lung cancer therapy. In the present study, the binding affinity of naturally occurring alkaloids, hordenine, vincamine, tryptamine, cinchonine, and colcemid was measured with PDK3. The molecular docking and fluorescence binding studies suggested that all these compounds show a considerable binding affinity for PDK3. Among them, the affinity of hordenine to the PDK3 was excellent (K = 106 M-1) which was further complemented by isothermal titration calorimetric measurements. Hordenine binds in the active site pocket of PDK3 and forms a significant number of non-covalent interactions with functionally important residues. All-atom molecular dynamics (MD) simulation study suggested that the PDK3-hordenine complex is stabilized throughout the trajectory of 100ns and leads to fewer conformational changes. The enzyme inhibition studies showed that hordenine inhibits the activity of PDK3 with an IC50 value of 5.4 µM. Furthermore, hordenine showed a cytotoxic effect on human lung cancer cells (A549 and H1299) with an admirable IC50 value. However, it did not inhibit the growth of HEK293 cells up to 200 µM, indicating its non-toxicity to non-cancerous cell lines. In summary, our findings provide the basis for the therapeutic implication of hordenine and its derivatives in lung cancer and PDK3-related diseases after required in vivo validation.

Imidazole and Benzimidazole Modified Half-Sandwich IridiumIII N-Heterocyclic Carbene Complexes: Synthesis, Anticancer Application, and Organelle Targeting

Herein, we report the synthesis, characterization and anticancer activity of a series of half-sandwich iridium^III imidazole and benzimidazole N-heterocyclic carbene (NHC) anticancer complexes, and the general formula of which can be expressed as [(η⁵-Cp^x)Ir(C^∧N)Cl]Cl (Cp^x: pentamethylcyclopentadienyl (Cp^*) or biphenyl derivatives (Cp^xbiph); C^∧N: imidazole and benzimidazole NHC chelating ligands). Compared with cis-platin, these complexes showed interesting antitumor activity against A549 cells. Complexes could bind to bovine serum albumin (BSA) by means of static quenching mode, catalyze the oxidation of nicotinamide adenine dinucleotide (NADH) and increase the levels of reactive oxygen species (ROS). Meanwhile, these complexes could arrest the cell cycles of A549 cells and influence the mitochondrial membrane potential significantly. Due to the inherent luminescence property, laser confocal test show that complexes could enter cells followed an energy-dependent mechanism and effectively accumulate in lysosome (the value of Pearson's co-localization coefficient is 0.70 after 1 h), further destroy lysosome integrity and induce apoptosis.

Calcium-Involved Action of Phytochemicals: Carotenoids and Monoterpenes in the Brain

Background: Neurodegenerative and mood disorders represent growing medical and social problems, many of which are provoked by oxidative stress, disruption in the metabolism of various neurotransmitters, and disturbances in calcium homeostasis. Biologically active plant compounds have been shown to exert a positive impact on the function of calcium in the central nervous system. Methods: The present paper reviews studies of naturally occurring terpenes and derivatives and the calcium-based aspects of their mechanisms of action, as these are known to act upon a number of targets linked to neurological prophylaxis and therapy. Results: Most of the studied phytochemicals possess anticancer, antioxidative, anti-inflammatory, and neuroprotective properties, and these have been used to reduce the risk of or treat neurological diseases. Conclusion: The neuroprotective actions of some phytochemicals may employ mechanisms based on regulation of calcium homeostasis and should be considered as therapeutic agents.

Evaluation of binding and inhibition mechanism of dietary phytochemicals with sphingosine kinase 1: Towards targeted anticancer therapy

Sphingosine kinase 1 (SphK1) has recently gained attention as a potential drug target for its association with cancer and other inflammatory diseases. Here, we have investigated the binding affinity of dietary phytochemicals viz., ursolic acid, capsaicin, DL-α tocopherol acetate, quercetin, vanillin, citral, limonin and simvastatin with the SphK1. Docking studies revealed that all these compounds bind to the SphK1 with varying affinities. Fluorescence binding and isothermal titration calorimetric measurements suggested that quercetin and capsaicin bind to SphK1 with an excellent affinity, and significantly inhibits its activity with an admirable IC50 values. The binding mechanism of quercetin was assessed by docking and molecular dynamics simulation studies for 100 ns in detail. We found that quercetin acts as a lipid substrate competitive inhibitor, and it interacts with important residues of active-site pocket through hydrogen bonds and other non-covalent interactions. Quercetin forms a stable complex with SphK1 without inducing any significant conformational changes in the protein structure. In conclusion, we infer that quercetin and capsaicin provide a chemical scaffold to develop potent and selective inhibitors of SphK1 after required modifications for the clinical management of cancer.

Identification and evaluation of glutathione conjugate gamma-l-glutamyl-l-cysteine for improved drug delivery to the brain

Glutathione (GU), an endogenous antioxidant tripeptide, is frequently transferred in the human brain through N-methyl-d-aspartate receptor (NMDAR), profusely expressed at the blood-brain barrier (BBB) junction. GU, also modifies the characteristics of tight junction proteins (occludin and claudin) at the site of BBB by depolarizing the enzyme, protein tyrosine phosphatase that manifests its usefulness for passive delivery of nanocarriers to the brain. GU, thus, represents itself as an ideal ligand for the surface decoration of nanocarriers to successfully administer them across the brain via receptor-mediated drug delivery pathway. Hence, we have employed here, in-silico approaches to identify the potential GU-like molecules, as appropriate ligand(s) for surface engineering of nanoconstruct with the purpose of attaining targeted drug delivery to the brain. Structure-based virtual screening methods was used to filter PubChem database for the identification of bioactive compounds with >95% structure similarity with GU. We have further screened the compounds against NMDAR using molecular docking approach. Top hits were selected based on their high binding affinities and selectivity towards NMDAR, and their binding pattern was analysed in detail. Finally, all atom molecular dynamics simulation for 100 ns was carried out on free NMDAR and in-presence of the selected GU-like compound, gamma-l-glutamyl-l-cysteine to evaluate complex stability and structural dynamics. In conclusion, gamma-l-glutamyl-l-cysteine may act as potential binding partner of NMDAR which can further be evaluated in drug delivery system to brain across the BBB.Communicated by Ramaswamy H. Sarma.

Identification of α-Mangostin as a Potential Inhibitor of Microtubule Affinity Regulating Kinase 4

Microtubule affinity regulating kinase 4 (MARK4) is a potential drug target for neuronal disorders and several types of cancers. Filtration of naturally occurring compound libraries using high-throughput screening and enzyme assay suggest α-mangostin is a potential inhibitor of MARK4. Structure-based docking and 100 ns molecular dynamics simulation revealed that the binding of α-mangostin stabilizes the MARK4 structure. Enzyme inhibition and binding studies showed that α-mangostin inhibited MARK4 in the submicromolar range with IC₅₀ = 1.47 μM and binding constant (K_a) 5.2 × 10⁷ M^-1. Cell-based studies suggested that α-mangostin inhibited the cell viability (MCF-7 and HepG2), induced apoptosis, arrested the cell cycle in the G0/G1 phase, and reduced tau-phosphorylation. This study implicates MARK4 as a new target of α-mangostin, adding an additional lead molecule to the anticancer repertoire.

Hesperidin-CAMKIV interaction and its impact on cell proliferation and apoptosis in the human hepatic carcinoma and neuroblastoma cells

Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a key regulatory molecule of cell signaling, and thereby controls its growth and proliferation, including expression of certain genes. The overexpression of CAMKIV is directly associated with the development of different types of cancers. Hesperidin is abundantly found in citrus fruits and exhibits wide range of pharmacological activities including anti-inflammatory, antibacterial and anticancerous effects. We have investigated binding mechanism of hesperidin with the CAMKIV using molecular docking methods followed by fluorescence quenching and isothermal titration calorimetric assays. An appreciable binding affinity of hesperidin was observed with CAMKIV during fluorescence quenching and isothermal titration calorimetric studies. Efficacy of hesperidin to inhibit the growth of human hepatic carcinoma (HepG2) and neuroblastoma (SH-SY5Y) cancer cell lines were investigated. Hesperidin has significantly reduced the proliferation of HepG2 and SH-SY5Y cells and induces apoptosis by activating the caspase-3-dependent intrinsic pathway through the upregulation of proapoptotic Bax protein. Hesperidin treatment reduces the mitochondrial membrane potential of HepG2 and SH-SY5Y cells. All these observations clearly anticipated hesperidin a potent inhibitor of CAMKIV which may be further exploited a newer therapeutic approach for the management of different cancer types.

Binding mechanism of caffeic acid and simvastatin to the integrin linked kinase for therapeutic implications: a comparative docking and MD simulation studies

Integrin linked kinase (ILK) is a Ser/Thr kinase, which regulates various integrin mediated signaling pathways, and is involved in cell adhesion, migration and differentiation. Alteration in the ILK is responsible for abnormal functioning of the cell system, which may lead to the cancer progression and metastasis. Caffeic acid (CA) and simvastatin are used as antioxidant and possess anticancer properties. Thus, inhibiting the kinase activity of ILK by CA and simvastatin may be implicated in the cancer therapy. In this study, we have performed molecular docking followed by 100 ns MD simulations to understand the interaction mechanism of ILK protein with the CA and simvastatin. Average potential energy was found to be highest in case of ILK-CA complex (-770,949 kJ/mol). Binding free energy was found to be higher in case of simvastatin than CA. Our results indicate that simvastatin binds more effectively to the active pocket of ILK. We further performed MTT assay to understand its anticancer potential. Simvastatin shows the IC₅₀ values for HepG2 and MCF-7 as 19.18 ± 0.12 and 13.84 ± 0.22 µM, respectively. However, the IC₅₀ value of CA on HepG2 and MCF-7 was reported as 175.50 ± 1.44 and 144.90 ± 1.53 µM, respectively. Our study provides a deeper insight into the binding mechanism of simvastatin and CA to ILK, which further opens a promising channel for their implications in cancer therapy.

Critical Assessment of the Interaction between DNA and Choline Amino Acid Ionic Liquids: Evidences of Multimodal Binding and Stability Enhancement

Long-term storage and stability of DNA is of paramount importance in biomedical applications. Ever since the emergence of ionic liquids (ILs) as alternate green solvents to aqueous and organic solvents, their exploration for the extraction and application of DNA need conscientious understanding of the binding characteristics and molecular interactions between IL and DNA. Choline amino acid ILs (CAAILs) in this regard seem to be promising due to their non-cytotoxic, completely biobased and environment-friendly nature. To unravel the key factors for the strength and binding mechanism of CAAILs with DNA, various spectroscopic techniques, molecular docking, and molecular dynamics simulations were employed in this work. UV-Vis spectra indicate multimodal binding of CAAILs with DNA, whereas dye displacement studies through fluorescence emission confirm the intrusion of IL molecules into the minor groove of DNA. Circular dichorism spectra show that DNA retains its native B-conformation in CAAILs. Both isothermal titration calorimetry and molecular docking studies provide an estimate of the binding affinity of DNA with CAAILs ≈ 4 kcal/mol. The heterogeneity in binding modes of CAAIL-DNA system with evolution of time was established by molecular dynamics simulations. Choline cation while approaching DNA first binds at surface through electrostatic interactions, whereas a stronger binding at minor groove occurs via van der Waals and hydrophobic interactions irrespective of anions considered in this study. We hope this result can encourage and guide the researchers in designing new bio-ILs for biomolecular studies in future.

High throughput screening, docking, and molecular dynamics studies to identify potential inhibitors of human calcium/calmodulin-dependent protein kinase IV

Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is associated with many diseases including cancer and neurodegenerative disorders and thus being considered as a potential drug target. Here, we have employed the knowledge of three-dimensional structure of CAMKIV to identify new inhibitors for possible therapeutic intervention. We have employed virtual high throughput screening of 12,500 natural compounds of Zinc database to screen the best possible inhibitors of CAMKIV. Subsequently, 40 compounds which showed significant docking scores (-11.6 to -10.0 kcal/mol) were selected and further filtered through Lipinski rule and drug likeness parameter to get best inhibitors of CAMKIV. Docking results are indicating that ligands are binding to the hydrophobic cavity of the kinase domain of CAMKIV and forming a significant number of non-covalent interactions. Four compounds, ZINC02098378, ZINC12866674, ZINC04293413, and ZINC13403020, showing excellent binding affinity and drug likeness were subjected to molecular dynamics simulation to evaluate their mechanism of interaction and stability of protein-ligand complex. Our observations clearly suggesting that these selected ligands may be further employed for therapeutic intervention to address CAMKIV associated diseases. Communicated by Ramaswamy H. Sarma.