Instigating the In Vitro Anticancer Activity of New Pyridine-Thiazole-Based Co(III), Mn(II), and Ni(II) Complexes: Synthesis, Structure, DFT, Docking, and MD Simulation Studies.

The perchlorate salt of (4-(4-methoxy phenyl)-2-(2-(1-pyridine-2-yl)ethylidene)hydrazinyl)thiazole (PytH·ClO4) and its metal perchlorate derivatives, namely, [Co(Pyt)2]ClO4 (1), [Mn(PytH)2](ClO4)2 (2), and [Ni(PytH)2](ClO4)2 (3), have been synthesized and characterized through single X-ray crystallography and spectroscopic methods. The ligand crystallizes in a space group P21/n in a nearly planar structure. The overall geometry of the complex salts is described as a distorted octahedron with a MN6 chromophore. The ligand (PytH·ClO4) behaves as a neutral N,N,N-tridentate donor toward the "soft" Mn(II) and Ni(II) centers, whereas the deprotonated ligand stabilizes the "hard" Co(III) center. The DNA binding constant (Kb) values of PytH·ClO4, 1, 2, and 3 are determined using the UV-vis spectroscopic method, and the Kb values are 9.29 × 105, 7.11 × 105, 8.71 × 105, and 7.82 × 105 mol-1, respectively, indicating the intercalative mode of interactions with CT-DNA. All the derivatives show effective antiproliferative activity against U-937 human monocytic tumor cells with IC50 values 4.374 ± 0.02, 5.583 ± 0.12, 0.3976 ± 0.05, and 11.63 ± 0.01 µM for PytH·ClO4, 1, 2, and 3, respectively. The best apoptosis mode of cell death is shown by 2 followed by PytH·ClO4 and 1 at an equivalent concentration of IC50 values. The combined molecular docking and dynamics simulation study evaluates the binding energies of anticancer agents, providing groove binding property with DNA. The 20 ns molecular dynamics simulation study reveals the maximum DNA binding stability of 2 corroborating the experimental results. The new class of metal derivatives of pyridine-thiazole can be used for advanced cancer therapeutics.

Structural-Genetic Characterization Of Novel Butaryl co-A Dehydrogenase and Proposition of Butanol Biosynthesis Pathway in Pusillimonas ginsengisoli SBSA.

Despite extensive use in the biofuel industry, only butyryl co-A dehydrogenase enzymes from the Clostridia group have undergone extensive structural and genetic characterization. The present study, portrays the characterization of structural, functional and phylogenetic properties of butyryl co-A dehydrogenase identified within the genome of Pusillimonas ginsengisoli SBSA. In silico characterization, homology modelling and docking data indicates that this protein is a homo-tetramer and 388 amino acid residue long, rich in alanine and leucine residue; having molecular weight of 42347.69 dalton. Its isoelectric point value is 5.78; indicate its neutral nature while 38.38 instability index value indicate its stable nature. Its thermostable nature evidenced by its high aliphatic index (93.14); makes its suitable for industry-based use. The secondary structure prediction analysis of butyryl co-A dehydrogenase unveiled that the proteins has secondary arrangements of 54% α-helix, 13% ß-stand and 5% disordered conformation. However, phylogenetic analysis clearly indicates that probably horizontal gene transfer is the primary mechanism of spreading of this gene in this organism. Notably, multiple sequence alignment study of phylogenetically diverse butyryl co-A dehydrogenase sequence highlighted the presence of conserved amino acid residues i.e. YXV/LGXKXWXS/T. Physicochemical characterization of other relevant proteins involved in butanol metabolism of SBSA also has been carried out. However, metabolic construction of functional butanol biosynthesis pathway in SBSA, enlightened its cost-effective potential use in biofuel industry as an alternate to Clostridia system.

Anti-cancer potential of (1,2-dihydronaphtho[2,1-b]furan-2-yl)methanone derivatives.

A series of 1,2-dihydronaphtho[2,1-b]furan derivatives were synthesized by cyclizing 1-(aryl/alkyl(arylthio)methyl)-naphthalen-2-ol and pyridinium bromides in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in very good yield. The synthesized compounds were evaluated for their anti-proliferative potential against human triple negative MDA-MB-468 and MCF-7 breast cancer cells and non-cancerous WI-38 cells (lung fibroblast cell) using MTT experiments. Among 21 synthesized compounds, three compounds (3a, 3b and 3 s) showed promising anti-cancer potential and compound 3b was found to have best anti-proliferative activities based on the results of several biochemical and microscopic experiments.

Homologs from sulfur oxidation (Sox) and methanol dehydrogenation (Xox) enzyme systems collaborate to give rise to a novel pathway of chemolithotrophic tetrathionate oxidation.

The SoxXAYZB(CD)2 -mediated pathway of bacterial sulfur-chemolithotrophy explains the oxidation of thiosulfate, sulfide, sulfur and sulfite but not tetrathionate. Advenella kashmirensis, which oxidizes tetrathionate to sulfate, besides forming it as an intermediate during thiosulfate oxidation, possesses a soxCDYZAXOB operon. Knock-out mutations proved that only SoxBCD is involved in A. kashmirensis tetrathionate oxidation, whereas thiosulfate-to-tetrathionate conversion is Sox independent. Expression of two glutathione metabolism-related proteins increased under chemolithotrophic conditions, as compared to the chemoorganotrophic one. Substrate-dependent oxygen consumption pattern of whole cells, and sulfur-oxidizing enzyme activities of cell-free extracts, measured in the presence/absence of thiol inhibitors/glutathione, corroborated glutathione involvement in tetrathionate oxidation. Furthermore, proteome analyses detected a sulfite:acceptor oxidoreductase (SorAB) exclusively under chemolithotrophic conditions, while expression of a methanol dehydrogenase (XoxF) homolog, subsequently named thiol dehydrotransferase (ThdT), was found to increase 3- and 10-fold during thiosulfate-to-tetrathionate conversion and tetrathionate oxidation respectively. A thdT knock-out mutant did not oxidize tetrathionate but converted half of the supplied 40 mM S-thiosulfate to tetrathionate. Knock-out of another thiosulfate dehydrogenase (tsdA) gene proved that both ThdT and TsdA individually converted ∼ 20 mM S-thiosulfate to tetrathionate. The overexpressed and isolated ThdT protein exhibited PQQ-dependent thiosulfate dehydrogenation, whereas its PQQ-independent thiol transfer activity involving tetrathionate and glutathione potentially produced a glutathione:sulfodisulfane adduct and sulfite. SoxBCD and SorAB were hypothesized to oxidize the aforesaid adduct and sulfite respectively.

Natural product inspired allicin analogs as novel anti-cancer agents.

A series of novel analogs of Allicin (S-allyl prop-2-ene-1-sulfinothioate) present in garlic has been synthesized in high yield. Synthesized 23 compounds were evaluated against different breast cancer cells (MDA-MB-468 and MCF-7) and non-cancer cells (WI38). Four compounds (3f, 3h, 3m and 3u) showed significant cytotoxicity against cancer cells whereas nontoxic to the normal cells. Based on the LD50 values and selectivity index (SI), compound 3h (S-p-methoxybenzyl (p-methoxyphenyl)methanesulfinothioate) was considered as most promising anticancer agent amongst the above three compounds. Further bio-chemical studies confirmed that compound 3h promotes ROS generation, changes in mitochondrial permeability transition and induced caspase mediated DNA damage and apoptosis.

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Chiral Chloroquine Analogues as Antimalarial Agents.

In a focused exploration, we designed, synthesized, and biologically evaluated chiral conjugated new chloroquine (CQ) analogues with substituted piperazines as antimalarial agents. In vitro as well as in vivo studies revealed that compound 7c showed potent activity (in vitro 50% inhibitory concentration, 56.98 nM for strain 3D7 and 97.76 nM for strain K1; selectivity index in vivo [up to at a dose of 12.5 mg/kg of body weight], 3,510) as a new lead antimalarial agent. Other compounds (compounds 6b, 6d, 7d, 7h, 8c, 8d, 9a, and 9c) also showed moderate activity against a CQ-sensitive strain (3D7) and superior activity against a CQ-resistant strain (K1) of Plasmodium falciparum Furthermore, we carried out docking and three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of all in-house data sets (168 molecules) of chiral CQ analogues to explain the structure-activity relationships (SAR). Our new findings specify the significance of the H-bond interaction with the side chain of heme for biological activity. In addition, the 3D-QSAR study against the 3D7 strain indicated the favorable and unfavorable sites of CQ analogues for incorporating steric, hydrophobic, and electropositive groups to improve the antimalarial activity.

In Silico Exploration for New Antimalarials: Arylsulfonyloxy Acetimidamides as Prospective Agents.

A strategy is described to identify new antimalarial agents to overcome the drug resistance and/or failure issues through in silico screening of multiple biological targets. As a part of this, three enzymes namely CTPS, CK, and GST were selected, from among 56 drug targets of P. falciparum, and used them in virtual screening of ZINC database entries which led to the design and synthesis of arylsulfonyloxy acetimidamides as their consensus inhibitors. From these, two compounds showed good activity against sensitive (3D7; IC50, 1.10 and 1.45 µM) and resistant (K1; IC50, 2.10 and 2.13 µM) strains of the parasite, and they were further investigated through docking and molecular dynamics simulations. The findings of this study collectively paved the way for arylsulfonyloxy acetimidamides as a new class of antimalarial agents.

Novel Sulforaphane Analog Disrupts Phosphatidylinositol-3-Kinase-Protein Kinase B Pathway and Inhibits Cancer Cell Progression via Reactive Oxygen Species-Mediated Caspase-Independent Apoptosis.

Sulforaphane, a naturally occurring isothiocyanate, has gained attention due to its tremendous anticancer potential. Thus, an array of sulforaphane analogs were synthesized and evaluated for their cytotoxic potentials on a wide range of malignant cell lines. Among these derivatives, compound 4a displayed exceptional potency in inhibiting the proliferation of cancer cell lines and a negligible effect on normal cell lines through G2/M phase arrest. The lead compound induced reactive oxygen species (ROS)-mediated mitochondrial dysfunction, leading to apoptosis. Further mechanistic studies established the interaction of the compound 4a with the insulin-like growth factor-1 receptor (IGF-R1) and blocking of the phosphatidylinositol-3-kinase (PI3K)-protein kinase B (PKB/Akt) pathway. This led to suppression of nuclear factor erythroid 2-related factor 2 (NRF-2) protein expression, thus increasing the free radicals in the tumor cells. Moreover, compound 4a induced ROS-mediated caspase-independent apoptosis. Finally, compound 4a reduced tumor progression in a 4T1 injected BALB/c syngeneic mice tumor model. In conclusion, this study summarizes the mechanism of compound 4a-mediated ROS-mediated caspase-independent apoptosis. According to the study's findings, compound 4a can be used as a powerful new anticancer agent to enhance cancer treatment.

Pyridones as NNRTIs against HIV-1 mutants: 3D-QSAR and protein informatics.

CoMFA and CoMSIA based 3D-QSAR of HIV-1 RT wild and mutant (K103, Y181C, and Y188L) inhibitory activities of 4-benzyl/benzoyl pyridin-2-ones followed by protein informatics of corresponding non-nucleoside inhibitors' binding pockets from pdbs 2BAN, 3MED, 1JKH, and 2YNF were analysed to discover consensus features of the compounds for broad-spectrum activity. The CoMFA/CoMSIA models indicated that compounds with groups which lend steric-cum-electropositive fields in the vicinity of C5, hydrophobic field in the vicinity of C3 of pyridone region and steric field in aryl region produce broad-spectrum anti-HIV-1 RT activity. Also, a linker rendering electronegative field between pyridone and aryl moieties is common requirement for the activities. The protein informatics showed considerable alteration in residues 181 and 188 characteristics on mutation. Also, mutants' isoelectric points shifted in acidic direction. The study offered fresh avenues for broad-spectrum anti-HIV-1 agents through designing new molecules seeded with groups satisfying common molecular fields and concerns of mutating residues.

Non-vesicular Lipid Transport Machinery in Trichomonas vaginalis: Novel Drug Targets against Trichomoniasis.

Eukaryotic cells have separate membrane-enclosed organelles with distinct biochemical identities and specialized functions. The unique characteristics of each organelle are regulated by asymmetric distribution and intra-cellular trafficking of two important biomolecules, proteins and lipids. Non-vesicular lipid transport facilitated by lipid transfer proteins performs essential roles in intracellular lipid trafficking and homeostasis, while vesicular transport regulates protein trafficking. Comparative analysis of lipid transport machinery in protists could help us to understand the basis of parasitism and insight into eukaryotic evolution. Trichomonas vaginalis, a parasitic protist, greatly depends on receptor-ligand-mediated signaling pathways for cellular differentiation, nutrient uptake, secretion of virulence factors, and pathogenesis. Lipids, despite being key molecules of signaling cascades, have mechanisms of intracellular transport that are largely unexplored in T. vaginalis. We have identified a repertoire of seventeen potential lipid transfer protein (LTP) homologs in T. vaginalis based on a domain-based search on TrichDB (genome database of Trichomonas) coupled with bioinformatics analyses, which indicates the presence of well-organized lipid transport machinery in this parasite. We emphasized here their evolutionary uniqueness and conservation and discussed their potential implications for parasite biology in regard to future therapeutic targets against Trichomoniasis.

Glutathione Depleting a Chemoselective Novel Pro-oxidant Nano Metal-Organic Framework Induced G2/M Arrest and ROS-Mediated Apoptotic Cell Death in a Human Triple-Negative Breast Cancer Cell Line.

The progression of a new class of compounds to inhibit the uncontrolled proliferation of carcinoma cells has become one of the most powerful weapons to combat "cancer". To this end, a new Mn(II)-based metal-organic framework, namely, [{Mn(5N3-IPA)(3-pmh)}(H2O)]α (5N3H2-IPA = 5-azidoisophthalic acid and 3-pmh = (3-pyridylmethylene)hydrazone), has been synthesized adopting a mixed ligand approach and exploited as a successful anticancer agent via systematic in vitro and in vivo studies. Single-crystal X-ray diffraction analyses depict that MOF 1 exhibits a 2D pillar-layer structure consisting of water molecules in each 2D void space. Due to the insolubility of the as-synthesized MOF 1, a green hand grinding methodology has been adopted to scale down the particle size to the nanoregime keeping its structural integrity intact. The nanoscale metal-organic framework (NMOF 1) adopts a discrete spherical morphology as affirmed by scanning electron microscopic analysis. The photoluminescence studies revealed that NMOF 1 is highly luminescent, enhancing its biomedical proficiency. Initially, the affinity of the synthesized NMOF 1 for GSH-reduced has been evaluated by various physicochemical techniques. NMOF 1 constrains the proliferation of cancer cells in vitro by inducing G2/M seizure and accordingly leads to apoptotic cell death. More significantly, compared to cancer cells, NMOF 1 exhibits less cytotoxicity against normal cells. It has been demonstrated that NMOF 1 interacts with GSH, causing a drop in cellular GSH levels and the production of intercellular ROS. It is quite intriguing that we discovered that NMOF 1-mediated ROS generation aids in significantly modifying the mitochondrial redox status, which is a crucial factor in apoptosis. According to mechanistic research, NMOF 1 increases the production of proapoptotic proteins and lowers the expression of antiapoptotic proteins, which significantly aids in activating caspase 3 and the subsequent cleavage of PARP1 and cell death via intrinsic apoptotic pathways. Finally, an in vivo investigation using immuno-competent syngeneic mice demonstrates that NMOF 1 can stop tumor growth without causing adverse side effects.

Insights from molecular dynamics simulations of TRPV1 channel modulators in pain.

TRPV1 is a nonselective cation channel vital for detecting noxious stimuli (heat, acid, capsaicin). Its role in pain makes it a potential drug target for chronic pain management, migraines, and related disorders. This review updates molecular dynamics (MD) simulation studies on the TRPV1 channel, focusing on its gating mechanism, ligand-binding sites, and implications for drug design. The article also explores challenges in developing modulators, SAR optimization, and clinical trial studies. Efforts have been undertaken to concisely present MD simulation findings, with a focus on their relevance to drug discovery.

In silico exploration and in vitro validation of the filarial thioredoxin reductase inhibitory activity of Scytonemin and its derivatives.

Lymphatic filariasis (LF) caused by the vector borne parasitic nematode Wuchereria bancrofti is of major concern of the World Health Organization (WHO). Lack of potential drug candidates worsens the situation. Presently available drugs are promising in killing the microfilaria (mf) but are not effective as adulticidal therapeutics. Previous studies have revealed that routine administration of the available drugs (albendazole, ivermectin and albendazole) sometime is associated with severe adverse effects (SAEs) in co-infection state. Therefore, potential and safe therapeutics are still required. Earlier studies on filarial thioredoxin reductase (TrxR) have shown that successful inhibition of it can lead to apoptotic death of the parasites. TrxR in filarial parasites plays a significant role in disease progression and pathogenesis, hence efficient non-reversible inhibition of TrxR can be a good strategy to treat LF. In this research, inhibitory potential of Scytonemin, a cyanobacterial metabolite on filarial TrxR was evaluated via different in silico methods and validated through in vitro experiments. Parasite death upon exposure to Scytonemin can be correlated with the TrxR inhibiting capacity of the compound. Therefore, this cyanobacterial-derived compound may possibly be used further as novel and safe therapeutic candidate against filarial infection.Communicated by Ramaswamy H. Sarma.

Conformational perturbation of SARS-CoV-2 spike protein using N-acetyl cysteine: an exploration of probable mechanism of action to combat COVID-19.

The infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) resulted in a pandemic with huge death toll and economic consequences. The virus attaches itself to the human epithelial cells through noncovalent bonding of its spike protein with the angiotensin-converting enzyme-2 (ACE2) receptor on the host cell. Based on in silico studies we hypothesized that perturbing the functionally active conformation of spike protein through the reduction of its solvent accessible disulfide bonds, thereby disintegrating its structural architecture, may be a feasible strategy to prevent infection by reducing the binding affinity towards ACE2 enzyme. Proteomics data showed that N-acetyl cysteine (NAC), an antioxidant and mucolytic agent been widely in use in clinical medicine, forms covalent conjugates with solvent accessible cysteine residues of spike protein that were disulfide bonded in the native state. Further, in silico analysis indicated that the presence of the selective covalent conjugation of NAC with Cys525 perturbed the stereo specific orientations of the interacting key residues of spike protein that resulted in threefold weakening in the binding affinity of spike protein with ACE2 receptor. Interestingly, almost all SARS-CoV-2 variants conserved cystine residues in the spike protein. Our finding results possibly provides a molecular basis for identifying NAC and/or its analogues for targeting Cys-525 of the viral spike protein as fusion inhibitor and exploring in vivo pharmaco-preventive and its therapeutic potential activity for COVID-19 disease. However, in-vitro assay and animal model-based experiment are required to validate the probable mechanism of action.Communicated by Ramaswamy H. Sarma.

Disruption of redox homeostasis with synchronized activation of apoptosis highlights the antifilarial efficacy of novel piperine derivatives: An in vitro mechanistic approach.

A series of novel piperine derivatives were synthesized with high yield and were evaluated for its antifilarial potential against the bovine filarial parasite Setaria cervi. Among 21 (3a-3u) compounds screened, three of them (3k, 3l, 3s) showed significant potential against all the developmental stages (oocytes, microfilariae and adult) of the filarial worm in time and dose dependent manner. 3l showed the highest efficacy among the selected three compounds. These three compounds were further evaluated for both in vitro and in vivo toxicity analyses which further fortified the benign nature of the selected compounds. The antifilarial activities they exhibited were clearly fuelled through disparity of the internal redox homeostasis as evidenced from the alterations in the enzymatic and non-enzymatic antioxidants level which ultimately shifted towards activation of pro-apoptotic signaling cascade eventually leading to the death of the parasites. The ability of the compound 3l to bind thioredoxin reductase and CED-3 protein are the key findings of this study. The present study supported with several biological experiments is therefore a maiden report on the antifilarial effectiveness of these novel piperine derivatives.

Aryl quinolinyl hydrazone derivatives as anti-inflammatory agents that inhibit TLR4 activation in the macrophages.

A series of aryl 7-chloroquinolinyl hydrazone derivatives (3a-u) have been synthesized in 55-76% yield using simple reaction condition. The synthesized compounds were evaluated for their anti-inflammatory activities based on their ability to inhibit pro-inflammatory cytokine secretion from the macrophages after stimulation with lipopolysaccharide (LPS). Three compounds appeared as promising anti-inflammatory agents. The mechanism of inflammatory activity of the potent compound 3e was further investigated using a series of biochemical, molecular and microscopic techniques. Further structure activity relationship (SAR) study was carried out to validate the anti-inflammatory activities of the active compounds. Our experimental data revealed that the active moiety i.e. compound 3e majorly causes inhibition of TLR4 signaling pathway and this appears to be the novel functional attribute of this compound.

Ichnocarpus frutescens (L.) R. Br. root derived phyto-steroids defends inflammation and algesia by pulling down the pro-inflammatory and nociceptive pain mediators: An in-vitro and in-vivo appraisal.

Ichnocarpus frutescens, a climber plant, is distributed all over India. As its different parts are used as anti-inflammatory agent, so we re-investigated the roots to isolate compounds and evaluate its biological efficacy. Also, in-silico molecular docking was carried out to elucidate the structure activity relationship (SAR) of isolated compounds toward identifies the drug target enzyme with validation, which was further supported by anti-inflammatory in-vitro and in-vivo experimental models. The compounds have been undertaken mainly to investigate the anti-inflammatory and analgesic efficacy along with molecular docking investigation followed by anti-proteinase, anti-denaturation and cyclooxygenase (COX) inhibition studies. Inflammatory cytokines like TNF-α and IL-6 were assayed from lipopolysaccharides (LPS) and Concavallin (CON A) stimulated human PBMC derived macrophages by Enyme linked immune sorbent assay (ELISA) method. The purity index of the lead compound was determined by HPLC. The compounds were illustrated as 2-hydroxy tricosanoic acid (1), stigmasterol glucoside (2), stigmasterol (3), ß-sitosterol (4) and ß-sitosterol glucoside (5). The test molecules showed significant anti-denaturation, anti-proteinase and analgesic effect validated with docking study. Compounds exhibited anti-inflammatory and pain killing action due to dexamethasone like phytosterol property. Promising anti-denaturation and anti-proteinase activity offered by the compound 5, may hold its promise to fight against arthritis by rejuvenating the osteoblast cells and destroying the bone-resorpting complex of hydrated protein, bone minerals by secreting the acid and an enzyme collagenase along with pain management. The lead bioactive compound i.e. ß-sitosterol glucoside (compound 5) demonstrated considerable anti-inflammatory activity showing more than 90% protection against the inflammatory cytokines at 50 µM dose. The anti-denaturation and COX-2 inhibition shown by the compound 5 was also noteworthy with the significant IC50 (ranging from 0.25 to 2.56 µM) that also supporting its future promise for developing as anti-inflammatory agent. Since the most bio-active compound (5) elicit promising acute anti-inflammatory action and peripheral anti-nociceptive pain killing action with a significant ED50 dose of 3.95 & 2.84 mg/kg i.p. respectively in the in-vivo animal model. It could suggest its potentiality as a good in-vivo bio available agent to be an emerging anti-inflammatory drug regimen scaffold in the future. It also establishes significant in-vitro and in-vivo result co-relation. Therefore, the compound 5 could be believed as a potent lead for designing anti-inflammatory, anti-arthritic drug or pain killer without showing any untoward effect.

N-hydroxy-substituted 2-aryl acetamide analogs: A novel class of HIV-1 integrase inhibitors.

An in silico method has been used to discover N-hydroxy-substituted 2-aryl acetamide analogs as a new class of HIV-1 integrase inhibitors. Based on the molecular requirements of the binding pocket of catalytic active site, two molecules (compounds 2 and 4b) were designed as fragments. These were further synthesized and biologically evaluated. In vitro potency along with docking studies highlighted compound 4b as an active fragment which was further used to synthesize new leads as HIV-1 integrase inhibitors. Finally, six promising compounds (compounds 5b, 5c, 5e, 6-2c, 6-3b, and 6-5b) were identified by integrase inhibition assay (>50% inhibition). Based on in vitro anti-HIV-1 activity in a reporter gene-based cell assay system, compounds 5d, 6s, and 6k were found as novel HIV-1 integrase inhibitors due to its better selectivity index. Additionally, docking study revealed the importance of H-bond as well as hydrophobic interactions with Asn155, Lys156, and Lys159 which were required for their anti-HIV-1 activity.