Unveiling critical structural features for effective HDAC8 inhibition: a comprehensive study using quantitative read-across structure-activity relationship (q-RASAR) and pharmacophore modeling.

Histone deacetylases constitute a group of enzymes that participate in several biological processes. Notably, inhibiting HDAC8 has become a therapeutic strategy for various diseases. The current inhibitors for HDAC8 lack selectivity and target multiple HDACs. Consequently, there is a growing recognition of the need for selective HDAC8 inhibitors to enhance the effectiveness of therapeutic interventions. In our current study, we have utilized a multi-faceted approach, including Quantitative Structure-Activity Relationship (QSAR) combined with Quantitative Read-Across Structure-Activity Relationship (q-RASAR) modeling, pharmacophore mapping, molecular docking, and molecular dynamics (MD) simulations. The developed q-RASAR model has a high statistical significance and predictive ability (Q2F1:0.778, Q2F2:0.775). The contributions of important descriptors are discussed in detail to gain insight into the crucial structural features in HDAC8 inhibition. The best pharmacophore hypothesis exhibits a high regression coefficient (0.969) and a low root mean square deviation (0.944), highlighting the importance of correctly orienting hydrogen bond acceptor (HBA), ring aromatic (RA), and zinc-binding group (ZBG) features in designing potent HDAC8 inhibitors. To confirm the results of q-RASAR and pharmacophore mapping, molecular docking analysis of the five potent compounds (44, 54, 82, 102, and 118) was performed to gain further insights into these structural features crucial for interaction with the HDAC8 enzyme. Lastly, MD simulation studies of the most active compound (54, mapped correctly with the pharmacophore hypothesis) and the least active compound (34, mapped poorly with the pharmacophore hypothesis) were carried out to validate the observations of the studies above. This study not only refines our understanding of essential structural features for HDAC8 inhibition but also provides a robust framework for the rational design of novel selective HDAC8 inhibitors which may offer insights to medicinal chemists and researchers engaged in the development of HDAC8-targeted therapeutics.

Chrysin-functionalized gold nanoparticles and paclitaxel exhibit synergistic impact on lung cancer cell lines via regulating the AKT/PPAR-ϒ/ß-catenin pathway.

Lung cancer has become progressively widespread, posing a challenge to traditional chemotherapeutic drugs such as platinum compounds and paclitaxel (PTX) owing to growing resistance. Along with that, the chemotherapeutic drugs infer major side effects. The usage of natural compounds as chemosensitizers to boost the efficacy of these chemotherapeutic drugs and minimizing their toxicity is a plausible approach. In our investigation, we employed PTX as the standard chemotherapeutic agent and utilized chrysin-functionalized gold nanoparticles (CHR-AuNPs) to augment its cytotoxicity. Gold nanoparticles were chosen for their inherent cytotoxic properties and ability to enhance chrysin's bioavailability and solubility. Characterization of CHR-AuNP revealed spherical nanoparticles within the nano-size range (35-70 nm) with a stable negative zeta potential of -22 mV, confirmed by physicochemical analyses including UV-visible spectroscopy, Fourier transform infrared (FTIR) spectral analysis, and visual observation of the wine-red coloration. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay cytotoxicity studies demonstrated CHR-AuNP's superior efficacy compared to CHR alone, with synergistic effects observed in combination with PTX, validated by Compusyn software. Morphological changes indicative of apoptosis were more pronounced with combined treatment, corroborated by acridine orange/ethidium bromide (AO/EtBr) staining and Annexin V assays. Furthermore, the combination treatment amplified reactive oxygen species (ROS) production and destabilized mitochondrial membrane potential, while altering the expression of pro-apoptotic and anti-apoptotic proteins. Exploring the mechanistic pathways, we found that the drugs upregulated PPAR-γ expression while suppressing Akt and overexpressing PTEN, thereby impeding the Wnt/ß-catenin pathway commonly dysregulated in lung cancer. This highlights the potential of low-dose combination therapy with PTX and CHR-AuNP as a promising strategy for addressing lung cancer's challenges.

Biphenylsulfonamides as effective MMP-2 inhibitors with promising antileukemic efficacy: Synthesis, in vitro biological evaluation, molecular docking, and MD simulation analysis.

Overexpression of matrix metalloproteinase-2 (MMP-2) possesses a correlation with leukemia especially chronic myeloid leukemia (CML). However, no such MMP-2 inhibitor has come out in the market to date for treating leukemia. In this study, synthesis, biological evaluation, and molecular modeling studies of a set of biphenylsulfonamide derivatives as promising MMP-2 inhibitors were performed, focusing on their potential applications as antileukemic therapeutics. Compounds DH-18 and DH-19 exerted the most effective MMP-2 inhibition (IC50 of 139.45 nM and 115.16 nM, respectively) with potent antileukemic efficacy against the CML cell line K562 (IC50 of 0.338 µM and 0.398 µM, respectively). The lead molecules DH-18 and DH-19 reduced the MMP-2 expression by 21.3% and 17.8%, respectively with effective apoptotic induction (45.4% and 39.8%, respectively) in the K562 cell line. Moreover, both these compounds significantly arrested different phases of the cell cycle. Again, both these molecules depicted promising antiangiogenic efficacy in the ACHN cell line. Nevertheless, the molecular docking and molecular dynamics (MD) simulation studies revealed that DH-18 formed strong bidentate chelation with the catalytic Zn2+ ion through the hydroxamate zinc binding group (ZBG). Apart from that, the MD simulation study also disclosed stable binding interactions of DH-18 and MMP-2 along with crucial interactions with active site amino acid residues namely His120, Glu121, His124, His130, Pro140, and Tyr142. In a nutshell, this study highlighted the importance of biphenylsulfonamide-based novel and promising MMP-2 inhibitors to open up a new avenue for potential therapy against CML.

Exploring molecular fingerprints of different drugs having bile interaction: a stepping stone towards better drug delivery.

Bile acids are amphiphilic substances produced naturally in humans. In the context of drug delivery and dosage form design, it is critical to understand whether a drug interacts with bile inside the gastrointestinal (GI) tract or not. This study focuses on the identification of structural fingerprints/features important for bile interaction. Molecular modelling methods such as Bayesian classification and recursive partitioning (RP) studies are executed to find important fingerprints/features for the bile interaction. For the Bayesian classification study, the ROC score of 0.837 and 0.950 are found for the training set and the test set compounds, respectively. The fluorine-containing aliphatic/aromatic group, the branched chain of the alkyl group containing hydroxyl moiety and the phenothiazine ring etc. are identified as good fingerprints having a positive contribution towards bile interactions, whereas, the bad fingerprints such as free carboxylate group, purine, and pyrimidine ring etc. have a negative contribution towards bile interactions. The best tree (tree ID: 1) from the RP study classifies the bile interacting or non-interacting compounds with a ROC score of 0.941 for the training and 0.875 for the test set. Additionally, SARpy and QSAR-Co analyses are also been performed to classify compounds as bile interacting/non-interacting. Moreover, forty-six recently FDA-approved drugs have been screened by the developed SARpy and QSAR-Co models to assess their bile interaction properties. Overall, this attempt may facilitate the researchers to identify bile interacting/non-interacting molecules in a faster way and help in the design of formulations and target-specific drug development.

Glycyrrhizin as a promising kryptonite against SARS-CoV-2: Clinical, experimental, and theoretical evidences.

COVID-19 is the most devastating disease in recent times affecting most people globally. The higher rate of transmissibility and mutations of SARS-CoV-2 along with the lack of potential therapeutics has made it a global crisis. Potential molecules from natural sources could be a fruitful remedy to combat COVID-19. This systematic review highlights the detailed therapeutic implication of naturally occurring glycyrrhizin and its related derivatives against COVID-19. Glycyrrhizin has already been established for blocking different biomolecular targets related to the SARS-CoV-2 replication cycle. In this article, several experimental and theoretical evidences of glycyrrhizin and related derivatives have been discussed in detail to evaluate their potential as a promising therapeutic strategy against COVID-19. Moreover, the implication of glycyrrhizin in traditional Chinese medicines for alleviating the symptoms of COVID-19 has been reviewed. The potential role of glycyrrhizin and related compounds in affecting various stages of the SARS-CoV-2 life cycle has also been discussed in detail. Derivatization of glycyrrhizin for designing potential lead compounds along with combination therapy with other anti-SARS-CoV-2 agents followed by extensive evaluation may assist in the formulation of novel anti-coronaviral therapy for better treatment to combat COVID-19.

A review of MMP-2 structures and binding mode analysis of its inhibitors to strategize structure-based drug design.

The protease enzyme, matrix metalloproteinase-2 (MMP-2) has been a target of choice for the drug development due to its multi-façade involvement in numerous diseased conditions including cancer. To find a selective MMP-2 inhibitor several computational strategies are employed in its design and discovery. In these strategies, protein structure of MMP-2 is an inevitable part to formulate effective structure-based drug design (SBDD) of selective MMP-2 inhibitors. In the present communication, several crystal structures of MMP-2 have been analyzed with different statistical parameters and their implementations in SBDD of inhibitors are scrutinized. In addition, binding mode analyses of various classes of inhibitors are discussed to pinpoint the effective design of selective inhibitors by maximizing its interaction with the MMP-2 enzyme binding site. This may provide a crucial insight for exploring the numerous possibilities for SBDD of MMP-2 inhibitors to accelerate anticancer drug discovery efforts.

How the structural properties of the indole derivatives are important in kinase targeted drug design?: A case study on tyrosine kinase inhibitors.

Kinases are considered as important signalling enzymes that illustrate 20% of the druggable genome. Human kinase family comprises >500 protein kinases and about 20 lipid kinases. Protein kinases are responsible for the mechanism of protein phosphorylation. These are necessary for regulation of various cellular activities including proliferation, cell cycle, apoptosis, motility, growth, differentiation, etc. Their deregulation leads to disruption of many cellular processes leading to different diseases most importantly cancer. Thus, kinases are considered as valuable targets in different types of cancer as well as other diseases. Researchers around the world are actively engaged in developing inhibitors based on distinct chemical scaffolds. Indole represents as a versatile scaffold in the naturally occurring and bioactive molecules. It is also used as a privileged scaffold for the target-based drug design against different diseases. This present article aim to review the applications of indole scaffold in the design of inhibitors against different tyrosine kinases such as epidermal growth factor receptors (EGFRs), vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptors (PDGFRs), etc. Important structure activity relationships (SARs) of indole derivatives were discussed. The present work is an attempt to summarize all the crucial structural information which is essential for the development of indole based tyrosine kinase inhibitors with improved potency.

A critical analysis of urea transporter B inhibitors: molecular fingerprints, pharmacophore features for the development of next-generation diuretics.

Urea transporter is a membrane transport protein. It is involved in the transferring of urea across the cell membrane in humans. Along with urea transporter A, urea transporter B (UT-B) is also responsible for the management of urea concentration and blood pressure of human. The inhibitors of urea transporters have already generated a huge attention to be developed as alternate safe class of diuretic. Unlike conventional diuretics, these inhibitors are suitable for long-term therapy without hampering the precious electrolyte imbalance in the human body. In this study, UT-B inhibitors were analysed by using multi-chemometric modelling approaches. The possible pharmacophore features along with favourable and unfavourable sub-structural fingerprints for UT-B inhibition are extracted. This information will guide the medicinal chemist to design potent UT-B inhibitors in future.

Exploring naphthyl derivatives as SARS-CoV papain-like protease (PLpro) inhibitors and its implications in COVID-19 drug discovery.

Novel coronavirus disease 2019 (COVID-19) emerges as a serious threat to public health globally. The rapid spreading of COVID-19, caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2), proclaimed the multitude of applied research needed not only to save the human health but also for the environmental safety. As per the recent World Health Organization reports, the novel corona virus may never be wiped out completely from the world. In this connection, the inhibitors already designed against different targets of previous human coronavirus (HCoV) infections will be a great starting point for further optimization. Pinpointing biochemical events censorious to the HCoV lifecycle has provided two proteases: a papain-like protease (PLpro) and a 3C-like protease (3CLpro) enzyme essential for viral replication. In this study, naphthyl derivatives inhibiting PLpro enzyme were subjected to robust molecular modelling approaches to understand different structural fingerprints important for the inhibition. Here, we cover two main aspects such as (a) exploration of naphthyl derivatives by classification QSAR analyses to find important fingerprints that module the SARS-CoV PLpro inhibition and (b) implications of naphthyl derivatives against SARS-CoV-2 PLpro enzyme through detailed ligand-receptor interaction analysis. The modelling insights will help in the speedy design of potent broad spectrum PLpro inhibitors against infectious SARS-CoV and SARS-CoV-2 in the future.

Host P2X7R-p38MAPK axis mediated intra-macrophage leishmanicidal activity of Spergulin-A.

Current drugs are inefficient for the treatment of visceral leishmaniasis an immunosuppressive ailment caused by Leishmania donovani. Regrettably, there is no plant-origin antileishmanial drug present. P2X7R is constitutively present on macrophage surfaces and can be a putative therapeutic target in intra-macrophage pathogens with function attributes towards inflammation, host cell apoptosis, altered redox, and phagolysosomal maturation by activating p38MAPK. Here we demonstrated that the initial interaction of Spergulin-A (Sp A), a triterpenoid saponin with RAW 264.7 macrophages was mediated through P2X7R involving the signaling cascade intermediates Ca++, p38MAPK, and NF-κß. Phospho (P)-p38MAPK involvement is shown to have specific and firm importance in leishmanial killing with increased NF-κßp65. Phago-lysosomal maturation by Sp A also campaigns for another contribution of P2X7R. In vivo evaluation of the anti-leishmanial activity of Sp A was monitored through expression analyses of P2X7R, P-p38MAPK, and NF-κßp65 in murine spleen and bone-marrow macrophages and supported Sp A being a natural compound of leishmanicidal functions which acted through the P2X7R-p38MAPK axis.

Ligand-based quantitative structural assessments of SARS-CoV-2 3CLpro inhibitors: An analysis in light of structure-based multi-molecular modeling evidences.

Due to COVID-19, the whole world is undergoing a devastating situation, but treatment with no such drug candidates still has been established exclusively. In that context, 69 diverse chemicals with potential SARS-CoV-2 3CLpro inhibitory property were taken into consideration for building different internally and externally validated linear (SW-MLR and GA-MLR), non-linear (ANN and SVM) QSAR, and HQSAR models to identify important structural and physicochemical characters required for SARS-CoV-2 3CLpro inhibition. Importantly, 2-oxopyrrolidinyl methyl and benzylester functions, and methylene (hydroxy) sulphonic acid warhead group, were crucial for retaining higher SARS-CoV-2 3CLpro inhibition. These GA-MLR and HQSAR models were also applied to predict some already repurposed drugs. As per the GA-MLR model, curcumin, ribavirin, saquinavir, sepimostat, and remdesivir were found to be the potent ones, whereas according to the HQSAR model, lurasidone, saquinavir, lopinavir, elbasvir, and paritaprevir were the highly effective SARS-CoV-2 3CLpro inhibitors. The binding modes of those repurposed drugs were also justified by the molecular docking, molecular dynamics (MD) simulation, and binding energy calculations conducted by several groups of researchers. This current work, therefore, may be able to find out important structural parameters to accelerate the COVID-19 drug discovery processes in the future.

HDAC6 as privileged target in drug discovery: A perspective.

HDAC6, a class IIB HDAC isoenzyme, stands unique in its structural and physiological functions. Besides histone modification, largely due to its cytoplasmic localization, HDAC6 also targets several non-histone proteins including Hsp90, α-tubulin, cortactin, HSF1, etc. Thus, it is one of the key regulators of different physiological and pathological disease conditions. HDAC6 is involved in different signaling pathways associated with several neurological disorders, various cancers at early and advanced stage, rare diseases and immunological conditions. Therefore, targeting HDAC6 has been found to be effective for various therapeutic purposes in recent years. Though several HDAC6 inhibitors (HDAC6is) have been developed till date, only two ACY-1215 (ricolinostat) and ACY-241 (citarinostat) are in the clinical trials. A lot of work is still needed to pinpoint strictly selective as well as potent HDAC6i. Considering the recent crystal structure of HDAC6, novel HDAC6is of significant therapeutic value can be designed. Notably, the canonical pharmacophore features of HDAC6is consist of a zinc binding group (ZBG), a linker function and a cap group. Significant modifications of cap function may lead to achieve better selectivity of the inhibitors. This review details the study about the structural biology of HDAC6, the physiological and pathological role of HDAC6 in several disease states and the detailed structure-activity relationships (SARs) of the known HDAC6is. This detailed review will provide key insights to design novel and highly effective HDAC6i in the future.

Protease targeted COVID-19 drug discovery and its challenges: Insight into viral main protease (Mpro) and papain-like protease (PLpro) inhibitors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) brutally perils physical and mental health worldwide. Unavailability of effective anti-viral drug rendering global threat of COVID-19 caused by SARS-CoV-2. In this scenario, viral protease enzymes are crucial targets for drug discovery. This extensive study meticulously focused on two viral proteases such as main protease (Mpro) and papain-like protease (PLpro), those are essential for viral replication. This review provides a detail overview of the targets (Mpro and PLpro) from a structural and medicinal chemistry point of view, together with recently reported protease inhibitors. An insight into the challenges in the development of effective as well as drug like protease inhibitors is discussed. Peptidomimetic and/or covalent coronavirus protease inhibitors possessed potent and selective active site inhibition but compromised in pharmacokinetic parameters to be a drug/drug like molecule. Lead optimization of non-peptidomimetic and/or low molecular weight compounds may be a better option for oral delivery. A masterly combination of adequate pharmacokinetic properties with coronavirus protease activity as well as selectivity will provide potential drug candidates in future. This study is a part of our endeavors which surely dictates medicinal chemistry efforts to discover effective anti-viral agent for this devastating disease.

Design, synthesis and binding mode of interaction of novel small molecule o-hydroxy benzamides as HDAC3-selective inhibitors with promising antitumor effects in 4T1-Luc breast cancer xenograft model.

Histone deacetylase 3 (HDAC3) is one of the most promising targets to develop anticancer therapeutics. In continuation of our quest for selective HDAC3 inhibitors, a series of small molecules having o-hydroxy benzamide as the novel zinc binding group (ZBG) has been introduced for the first time that can be able to produce good HDAC3-selectivity over other HDACs. The most promising HDAC3 inhibitors, 11a and 12b, displayed promising in vitro anticancer activities with less toxicity to normal kidney cells. These compounds significantly upregulate histone acetylation and induce apoptosis with a G2/M phase arrest in B16F10 cells. Compound 11a exhibited potent antitumor efficacy in 4T1-Luc breast cancer xenograft mouse model in female Balb/c mice. It also showed significant tumor growth suppression with no general toxicity and extended survival rates post-tumor resection. It significantly induced higher ROS generation, leading to apoptosis. No considerable toxicity was noticed in major organs isolated from the compound 11a-treated mice. Compound 11a also induced the upregulation of acH3K9, acH4K12, caspase-3 and caspase-7 as analyzed by immunoblotting with treated tumor tissue. Overall, HDAC3 selective inhibitor 11a might be a potential lead for the clinical translation as an emerging drug candidate.

Synthesis, biological evaluation, and molecular docking analysis of novel linker-less benzamide based potent and selective HDAC3 inhibitors.

A series of novel linker-less benzamides with different aryl and heteroaryl cap groups have been designed, synthesized, and screened as potent histone deacetylase (HDAC) inhibitors with promising anticancer activity. Two lead compounds 5e and 5f were found as potent and highly selective HDAC3 inhibitors over other Class-I HDACs and HDAC6. Compound 5e bearing a 6-quinolinyl moiety as the cap group was found to be a highly potent HDAC3 inhibitor (IC50 = 560 nM) and displayed 46-fold selectivity for HDAC3 over HDAC2, and 33-fold selectivity for HDAC3 over HDAC1. The synthesized compounds possess antiproliferative activities against different cancer cell lines and significantly less cytotoxic to normal cells. Molecular Docking studies of compounds 5e and 5f reveal a similar binding mode of interactions as CI994 at the HDAC3 active site. These observations agreed with the in vitro HDAC3 inhibitory activities. Significant enhancement of the endogenous acetylation level on H3K9 and H4K12 was found when B16F10 cells were treated with compounds 5e and 5f in a dose-dependent manner. The compounds induced apoptotic cell death in Annexin-V/FITC-PI assay and caused cell cycle arrest at G2/M phase of cell cycle in B16F10 cells. These compounds may serve as potential HDAC3 inhibitory anticancer therapeutics.

First structure-activity relationship analysis of SARS-CoV-2 virus main protease (Mpro) inhibitors: an endeavor on COVID-19 drug discovery.

Main protease (Mpro) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) intervenes in the replication and transcription processes of the virus. Hence, it is a lucrative target for anti-viral drug development. In this study, molecular modeling analyses were performed on the structure activity data of recently reported diverse SARS-CoV-2 Mpro inhibitors to understand the structural requirements for higher inhibitory activity. The classification-based quantitative structure-activity relationship (QSAR) models were generated between SARS-CoV-2 Mpro inhibitory activities and different descriptors. Identification of structural fingerprints to increase or decrease in the inhibitory activity was mapped for possible inclusion/exclusion of these fingerprints in the lead optimization process. Challenges in ADME properties of protease inhibitors were also discussed to overcome the problems of oral bioavailability. Further, depending on the modeling results, we have proposed novel as well as potent SARS-CoV-2 Mpro inhibitors.

Chemical-informatics approach to COVID-19 drug discovery: Exploration of important fragments and data mining based prediction of some hits from natural origins as main protease (Mpro) inhibitors.

As the world struggles against current global pandemic of novel coronavirus disease (COVID-19), it is challenging to trigger drug discovery efforts to search broad-spectrum antiviral agents. Thus, there is a need of strong and sustainable global collaborative works especially in terms of new and existing data analysis and sharing which will join the dots of knowledge gap. Our present chemical-informatics based data analysis approach is an attempt of application of previous activity data of SARS-CoV main protease (Mpro) inhibitors to accelerate the search of present SARS-CoV-2 Mpro inhibitors. The study design was composed of three major aspects: (1) classification QSAR based data mining of diverse SARS-CoV Mpro inhibitors, (2) identification of favourable and/or unfavourable molecular features/fingerprints/substructures regulating the Mpro inhibitory properties, (3) data mining based prediction to validate recently reported virtual hits from natural origin against SARS-CoV-2 Mpro enzyme. Our Structural and physico-chemical interpretation (SPCI) analysis suggested that heterocyclic nucleus like diazole, furan and pyridine have clear positive contribution while, thiophen, thiazole and pyrimidine may exhibit negative contribution to the SARS-CoV Mpro inhibition. Several Monte Carlo optimization based QSAR models were developed and the best model was used for screening of some natural product hits from recent publications. The resulted active molecules were analysed further from the aspects of fragment analysis. This approach set a stage for fragment exploration and QSAR based screening of active molecules against putative SARS-CoV-2 Mpro enzyme. We believe the future in vitro and in vivo studies would provide more perspectives for anti-SARS-CoV-2 agents.

Unmasking of crucial structural fragments for coronavirus protease inhibitors and its implications in COVID-19 drug discovery.

Fragment based drug discovery (FBDD) by the aid of different modelling techniques have been emerged as a key drug discovery tool in the area of pharmaceutical science and technology. The merits of employing these methods, in place of other conventional molecular modelling techniques, endorsed clear detection of the possible structural fragments present in diverse set of investigated compounds and can create alternate possibilities of lead optimization in drug discovery. In this work, two fragment identification tools namely SARpy and Laplacian-corrected Bayesian analysis were used for previous SARS-CoV PLpro and 3CLpro inhibitors. A robust and predictive SARpy based fragments identification was performed which have been validated further by Laplacian-corrected Bayesian model. These comprehensive approaches have advantages since fragments are straight forward to interpret. Moreover, distinguishing the key molecular features (with respect to ECFP_6 fingerprint) revealed good or bad influences for the SARS-CoV protease inhibitory activities. Furthermore, the identified fragments could be implemented in the medicinal chemistry endeavors of COVID-19 drug discovery.

Photodynamic activity attained through the ruptured π-conjugation of pyridyl groups with a porphyrin macrocycle: synthesis and the photophysical and photobiological evaluation of 5-mono-(4-nitrophenyl)-10,15,20-tris-[4-(phenoxymethyl)pyridine]-porphyrin and its Zn(ii) complex.

This article compares a reported hydrophobic and photobiologically inert porphyrin synthon, (NPh)TPyP, bearing a single meso-4-nitrophenyl group and three meso-pyridyl groups (A3B type) with a new photobiologically active metal-free porphyrin, P3N, and its zinc-complex, P3NZn, which bear a meso-4-nitrophenyl group along with three distal pyridyl groups. Both P3N and P3NZn experience ruptured π-conjugation with the porphyrin macrocycle and attain hydrophilicity, as indicated via density functional theory (DFT) calculations, becoming photobiologically active under in vitro conditions. The non-invasive photodynamic activity (PDA) predominantly shown by the zinc-complex P3NZn (with higher hydrophilicity) towards KRAS-mutated human lung-cancer cells (A549) was studied. The results indicate the existence of intracellular singlet oxygen inflicted anticancer PDA, which is apparent through the upregulation of intracellular reactive oxygen species (ROS) and the downregulation of both intracellular superoxide dismutase (SOD) and intracellular reduced glutathione (GSH) levels. The trends obtained from both SOD and GSH assays were indicators of therapeutic defence against oxidative stress via neutralizing superoxide anions (SOA).

Chrysin-loaded PLGA attenuates OVA-induced allergic asthma by modulating TLR/NF-κB/NLRP3 axis.

Asthma, one of the significant public health problems, is triggered by certain inflammatory processes in the airways that are not addressed propitiously by current therapies. Though pieces of evidence on allergic asthma mitigation by the anti-inflammatory bioflavonoid chrysin (CHR) are accumulating, poor bioavailability, and low solubility curtail drug development. To overcome these shortcomings, CHR loaded nanoparticle (CHR-NP) was formulated, and its salutary effect in preclinical murine allergic asthma model via the peroral route was evaluated. The spherical nanosized particles showed slow, sustained release in vitro. Moreover, CHR-NP dramatically reduced the serum IgE, ovalbumin (OVA)-induced lung histological alteration, as well as Th2 (T-helper 2) cytokines in the bronchoalveolar lavage fluid (BALF). It also suppressed the elevated serum pro-inflammatory cytokines and their upstream TLR/NF-κB/NLRP3 pathway activation in lung superior to CHR and almost identical to dexamethasone (DEX). Thus this study suggests the potentiality of CHR-NP in ameliorating allergic asthma progression.