Plausible Mechanism Of Action Research Articles

Abstract CT287: LINNOVATE: A Phase 1/2 study of safety/efficacy using lurbinectedin, combined with ipilimumab, and nivolumab for advanced soft tissue sarcomas (NCT05876715)

Abstract Background: Sarcoma cells are most immunogenic earlier in the course of the disease. Therefore, immune checkpoint inhibitors such as ipilimumab (ipi) and nivolumab (nivo), that promote sustained T-cell activation by suppressing T regs would be most effective when given as first line therapy, together with a tumoricidal agent, such as lurbinectedin, whose plausible mechanism of action is not only to destroy the cancer cells and expose the tumor neoantigens for immune recognition, but also to destroy growth promoting factors in the tumor microenvironment. In the SAINT phase 2 study using ipi, nivo and trabectedin as first line therapy for advanced soft tissue sarcomas (STS; n=79), there were 6 complete responses, 14 partial responses, 49 stable disease, 25.3% best response rate, 87.3% disease control rate; median PFS, 6.7 months, median OS, 24.6 months (Gordon et al, Cancers vol. 15, 906, 2023). Lurbinectedin is a synthetic marine-derived agent and an analog of trabectedin. Therefore, we expect that lurbinectedin will be as effective as trabectedin when used together with ipi and nivo as first line therapy for advanced STS. Methods: Objective 1: Assess MTD of lurbinectedin. Objective 2: Evaluate PFS, OS, incidence and severity of adverse events; Correlative: Correlate response with ctDNA using Signatera. This is an open label, dose-seeking phase 1/2 study. The phase 1 part employs standard “cohort of three” design with a DLT window of 6 weeks. Treatment schedule: Ipi 1 mg/kg IV q 12 weeks; Nivo 3 mg/kg IV q 2 weeks; escalating doses of lurbinectedin from 2.6 mg/m2 to 3.2 mg/m2 IV q 3 weeks. Phase 2 part follows completion of phase 1 part wherein additional 28-34 participants will receive lurbinectedin at the MTD with fixed doses of Ipi and Nivo. Participants may continue treatment until significant disease progression or unacceptable toxicity occurs. Eligible patients are 18 years of age or older, previously treated in phase 1 and previously untreated in phase 2 with confirmed diagnosis of advanced STS, adequate hematologic and organ function, and no history of autoimmune disorder. To date, 6 patients in phase 1 have been dosed. Citation Format: Erlinda M. Gordon, Nadezhda Omelchenko, Samantha Jeffrey, Vaishali Kumar, Neal S. Chawla, Mahesh Seetharam, Victoria Chua, Ania Moradkhani, Doris Quon, Steven Wong, Sant Chawla. LINNOVATE: A Phase 1/2 study of safety/efficacy using lurbinectedin, combined with ipilimumab, and nivolumab for advanced soft tissue sarcomas (NCT05876715) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT287.

Nitroprusside and metal nitroprusside nano analogues for cancer therapy.

Sodium nitroprusside (SNP), U.S approved drug has been used in clinical emergency as a hypertensive drug for more than a decade. It is well established for its various biomedical applications such as angiogenesis, wound healing, neurological disorders including anti-microbial applications etc. Apart from that, SNP have been considered as excellent biomedical materials for its use as anti-cancer agent because of its behavior as NO-donor. Recent reports suggest that incorporation of metals in SNP/encapsulation of SNP in metal nanoparticles (metal nitroprusside analogues) shows better therapeutic anti-cancer activity. Although there are numerous reports available regarding the biological applications of SNP and metal-based SNP analogue nanoparticles, unfortunately there is not a single comprehensive review which highlights the anti-cancer activity of SNP and its derivative metal analogues in detail along with the future perspective. To this end, the present review article focuses the recent development of anti-cancer activity of SNP and metal-based SNP analogues, their plausible mechanism of action, current status. Furthermore, the future perspectives and challenges of these biomedical materials are also discussed. Overall, this review article represents a new perspective in the area of cancer nanomedicine that will attract a wider spectrum of scientific community.

19 Schiff bases as antimycobacterial agents: synthesis, molecular docking and a plausible mechanism of action.

Aim: To discover novel anti-Mycobacterium tuberculosis (Mtb) drugs, 19 compounds were synthesized; their anti-Mtb effects were evaluated and mechanisms of action were preliminarily explored. Materials & methods: The compounds were synthesized and their anti-Mtb activity was elucidated using resazurin microtiter assays. The plausible target of the potential compound was investigated by microimaging techniques, gas chromatography-mass spectrometry analysis and molecular docking. Results: 19compounds inhibited Mtb growth with minimum inhibitory concentrationsranging from 1 to 32μg/ml. Compounds 1-17 showed inhibition of Mtb KatG enzyme. Compound 19, the most potent, might be an inhibitor of Pks13 polyketide synthase. Conclusion: This study suggests that 2-((6-fluoropyridin-3-yl)methylene) hydrazine-1-carbothioamide (19) is a potential anti-Mtb lead compound with a novel mechanism of action.

Synthesis, antibiofilm activity and molecular docking of N-acylhomoserine lactones containing cinammic moieties

We prepared a series of cinnamoyl-containing furanones by an affordable and short synthesis. The nineteen compounds hold a variety of substituents including electron-donating, electron-withdrawing, bulky and meta-substituted phenyls, as well as heterocyclic rings. Compounds showed antibiofilm activity in S. aureus, K. pneumoniae and, more pronounced, against P. aeruginosa. The disruption of quorum sensing (QS) was tested using the violacein test and molecular docking predicted the antagonism of LasR as a plausible mechanism of action. The trimethoxylated and diene derivatives showed the best antibiofilm and anti-QS properties, thus becoming candidates for further modifications.

Evidence and possible mechanism of Scutellaria baicalensis and its bioactive compounds for hepatocellular carcinoma treatment

Background Traditional Chinese medicines have been reported to have outstanding effects in the treating of hepatocellular carcinoma. Scutellaria baicalensis (S. baicalensis) has demonstrated anti-tumor, anti-angiogenic, and anti-inflammatory properties. Baicalein, wogonin, and baicalin are the main pharmacologically bioactive compounds of S. baicalensis. Methods Eight electronic databases were searched to select articles published from their inception to 30 May 2022. For selected articles, clinical and preclinical data was obtained on the use of S. baicalensis and its bioactive compounds in hepatocellular carcinoma therapy. Statistical analyses were performed using RevMan version 5.3 and Stata software. Quality assessment of the studies was performed using Cochrane and Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)’s risk of bias tools. Results Seven clinical and 17 preclinical in vivo studies along with 31 in vitro studies were included in this research. Meta-analysis showed that a Chinese herbal medicine preparation, with S. baicalensis as the sovereign herb, combined with Transcatheter arterial chemoembolization (TACE) or primary treatment, could lead to a significantly improved tumor objective response rate (Risk ratio (RR) = 1.57, 95% confidence interval (CI): [1.30, 1.90], p < 0.00001). Scutellaria baicalensis-based extracts (standard mean difference (SMD) = –0.86, 95%CI: [–1.20, −0.53], p < 0.00001), baicalein (SMD = –4.80, 95%CI: [–6.66, − 2.95], p < 0.00001), baicalin (SMD = –2.28, 95%CI [–3.26, −1.30], p < 0.00001) and wogonin (SMD = –1.41, 95%CI [–2.26, −0.57], p < 0.00001) slowed tumor growth in vivo. These outcomes might be linked to the mechanism by which S. baicalensis promotes apoptosis, induces autophagy, and blocks the expression of vascular endothelial growth factor (p < 0.05). Conclusion Based on experimental and clinical evidence, we believe that S. baicalensis and its bioactive compounds have therapeutic potential and plausible mechanisms of action against hepatocellular carcinoma, in terms of efficacy and safety.

Converging thiolactone and quinoline scaffolds: New potential antitubercular conjugates

Tuberculosis infections pose a serious challenge, particularly because of the emergence of drug resistant mycobacterial strains, highlighting the need of development of new drugs. We report twenty-four new compounds that are designed and synthesized by converging thiolactone and quinoline scaffolds as potential antitubercular entities. Bacterial assay demonstrated one of the conjugates, 4f to be a highly potent molecule with minimum inhibitory concentration (MIC) value of 0.5 μg/mL, comparable to first line drugs. Remarkably, the conjugate 4f demonstrated similar potency against rifampicin and multidrug resistant mycobacterial strains while exhibiting little toxicity against normal cells. In vivo studies demonstrated the promising potential of the conjugate for further development. Finally, a molecular docking study was conducted on four different targets to elucidate the plausible mechanism of action.

Bioactive Pyrrolo[2,1-f][1,2,4]triazines: Synthesis, Molecular Docking, In Vitro Cytotoxicity Assay and Antiviral Studies

A series of 2,4-disubstituted pyrrolo[2,1-f][1,2,4]triazines containing both aryl and thienyl substituents were synthesized by exploiting the 1,3-cycloaddition reaction of N(1)-ethyl-1,2,4-triazinium tetrafluoroborates with dimethyl acetylenedicarboxylate. The antiviral activity of the synthesized compounds against influenza virus strain A/Puerto Rico/8/34 (H1N1) was studied in experiments on Madin-Darby canine kidney (MDCK) cell culture. Among the pyrrolo[2,1-f][1,2,4]triazine derivatives, compounds with low toxicity and high antiviral activity were identified. Dimethyl 4-(4-methoxyphenyl)-7-methyl-2-p-tolylpyrrolo[2,1-f][1,2,4]triazine-5,6-dicarboxylate was found to demonstrate the best antiviral activity (IC50 4 µg/mL and selectivity index 188). Based on the results of in vitro tests and molecular docking studies performed, a plausible mechanism of action for these compounds was suggested to involve inhibition of neuraminidase.

Exploration of antiproliferative potential of modified triazole-benzohydrazone scaffold: Multitarget approach.

A novel series of triazole-benzohydrazone hybrids was efficiently designed and synthesized as antiproliferative agents, targeting different kinases. All compounds were screened via the National Cancer Institute (NCI) against 60 cancer cell lines, where compounds 16, 17, and 18 exhibited growth inhibition percent(GI%)of various leukemia subpanels with values of 70.33%, 64.13%, and 76.03%, respectively. Compound 18 showed broad-spectrum antiproliferative efficacy towardmost cancer cells, with outstanding potency regarding melanoma (MALME-3M GI% = 101.82%) and breast cancer cell lines (MCF7 GI% = 85.87%), while proving safe towardthe WI-38 normal cell line, compared to doxorubicin. Multikinase investigation including vascular endothelial growth factor receptor 2 (VEGFR-2), mesenchymal epithelial transition factor (c-Met), proto-oncogene B-Raf, mitogen-activated protein kinase kinase, extracellular signal-regulated kinase, and phosphoinositide 3-kinase was accomplished to reveal its plausible mechanism of action, giving the ultimate potency against both VEGFR-2 and c-Met with IC50 values of 0.055and 0.042 μM, respectively, while displaying moderate to good inhibition concerning the remaining kinases. DNA binding capability was excluded using the methyl green colorimetric assay. Further, it exhibited both early and late apoptotic induction by about 16- and 9.4-fold over the control, respectively, triggering cell cycle arrest in the G2/M phase. Physicochemical properties and bioavailability radar plot inferred drug-likeness characteristics for compound 18. The molecular docking study assessed the binding pattern with the active sites of c-Met and VEGFR-2.

Updated Perspectives on the Diagnosis and Management of Familial Adenomatous Polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominant cancer predisposition syndrome marked by extensive colorectal polyposis and a high risk of colorectal cancer (CRC). Having access to screening and enrollment programs can improve survival for patients with FAP by enabling them to undergo surgery before the development of colorectal cancer. Provided that there are a variety of surgical options available to treat colorectal polyps in patients with adenomatous polyposis, the appropriate surgical option for each patient should be considered. The gold-standard treatment to reduce this risk is prophylactic colectomy, typically by the age of 40. However, colectomy is linked to morbidity and constitutes an ineffective way at preventing extra-colonic disease manifestations, such as desmoid disease, thyroid malignancy, duodenal polyposis, and cancer. Moreover, extensive studies have been conducted into the use of chemopreventive agents to prevent disease progression and delay the necessity for a colectomy as well as the onset of extracolonic disease. The ideal chemoprevention agent should demonstrate a biologically plausible mechanism of action and provide safety, easy tolerance over an extended period of time and a lasting and clinically meaningful effect. Although many pharmaceutical and non-pharmaceutical products have been tested through the years, there has not yet been a chemoprevention agent that meets these criteria. Thus, it is necessary to develop new FAP agents that target novel pathways, such as the mTOR pathway. The aim of this article is to review the prior literature on FAP in order to concentrate the current and future perspectives of diagnosis and treatment. In conclusion, we will provide an update on the diagnostic and therapeutic options, surgical or pharmaceutical, while focusing on the potential treatment strategies that could further reduce the risk of CRC.

MicroRNA sequencing for biomarker detection in the diagnosis, classification and prognosis of Diffuse Large B Cell Lymphoma

Despite being considered a single disease, Diffuse Large B Cell Lymphoma (DLBCL) presents with variable backgrounds, which results in heterogeneous outcomes among patients, with 40% of them still having primary refractory disease or relapse. Thus, novel biomarkers are needed. In addition, multiple factors regarding its pathogenesis remain unclear. In this context, recent investigations point to the relevance of microRNAs (miRNAs) in cancer. However, regarding DLBCL, there is inconsistency in the data reported. Therefore, in this work, the main goals were to determine a miRNA set with utility as biomarkers for DLBCL diagnosis, classification, prognosis and treatment response, as well as to decipher the mechanism of action of deregulated miRNAs in the origin of the disease. We analyzed miRNA expression in a cohort of 78 DLBCL patients and 17 controls using small RNA sequencing and performed a miRNA-mRNA interaction network analysis. This way, we were able to define new miRNA expression signatures for diagnosis, classification, treatment response and prognosis, and we identified plausible mechanisms of action by which deregulated miRNAs could be involved in DLBCL pathogenesis. In summary, our study remarks that miRNAs could play an important role in DLBCL.

Antimalarial Drugs Induce the Selective Folding of Human Telomeric G-Quadruplex in a Cancer-Mimicking Microenvironment.

Regulating the equilibrium between the duplex form of DNA and G-quadruplex (Gq) and stabilizing the folded Gq are the critical factors for any drug to be effective in cancer therapy due to the direct involvement of Gq in controlling the transcription process. Antimalarial drugs are in the trial stage for different types of cancer diseases; however, the plausible mechanism of action of these drug molecules is not well known. Hence, we investigate the plausible role of antimalarial drugs in the folding and stabilization of Gq-forming DNA sequences from the telomere and promoter gene regions by varying the salt (KCl) concentrations, mimicking the in vitro cancerous and normal cell microenvironments. The study reveals that antimalarial drugs fold and stabilize specifically to telomere Gq-forming sequences in the cancerous microenvironment than the DNA sequences located in the promoter region of the gene. Antimalarial drugs are not only able to fold Gq but also efficiently protect them from unfolding by their complementary strands, hence significantly biasing the equilibrium toward the Gq formation from the duplex. In contrast, in a normal cell microenvironment, K+ controls the folding of telomeres, and the role of antimalarial drugs is not prominent. This study suggests that the action of antimalarial drugs is sensitive to the cancer microenvironment as well as selective to the Gq-forming region.

Novel pyrimidine – Imines against tuberculosis: Rationale, in vitro, in silico studies and mechanistic insights

Two series of novel multifunctional pyrimidine–imine hybrids were synthesized and evaluated for their antitubercular and antimicrobial properties. A novel synthetic methodology utilizing water as a green solvent and a catalytic amount of HCl resulted in the isolation of barbituric acid – uracil – imine hybrids in moderate to good yields. The in vitro antitubercular activity of the compounds revealed exceptional activity, with D16 showing MIC100 at 6 µM, which is comparable to the commercial drug ethambutol with MIC100 at 7.63 µM. Compounds D7, D12, D18, D19, and D20 also showed MIC100 at concentrations ranging from 10.60 µM to 50.86 µM. The compounds were also noncytotoxic in the mouse macrophage cell line (RAW 264.7) at 25 µg/ml concentration. Molecular docking studies were carried out against M.tb thymidylate kinase to gain insights into the binding modes of the compounds and understand the plausible mechanism of action. The compound D16 outperformed all compounds with a MIC100 of 6 µM, attributed to its strong binding affinity with thymidylate kinase valued at -9.1 kcal/mol. Compounds also showed promising activity against pathogenic bacterial and fungal strains, with the M series being more active. Even though the compounds showed broad-spectrum antibacterial activity against Gram-positive and Gram-negative bacteria, the inhibitory effect on the growth of Gram-positive bacteria was more significant. This may be due to the structural difference in the cell wall composition of both bacteria. Compound M9 displayed moderate to good activity against bacteria and various species of Candida. This is the first-ever report on the synthesis and biological evaluation of uracil–imine hybrids as antitubercular and antimicrobial agents.

A mononuclear N,N,N,O donor schiff base Cu(II) complex inhibits bacterial biofilm formation and promotes apoptosis and cell cycle arrest in prostate cancer cells

In this work, we report a distorted square pyramidal mononuclear copper(II) complex [Cu(L)(NCS)] (1) which was obtained by the reaction of the aqueous solution of ammonium thiocyanate to a methanolic solution of copper nitrate trihydrate and corresponding Schiff-base ligands. Schiff bases, HL (C12H19N3O) act as a tetradentate Schiff base, derived from 1:1 condensation of o-hydroxyacetophenone and diethylenetriamine. The synthesized complex has been successfully characterized based on elemental analysis and Infrared (IR) spectroscopy. The structure of complex 1 was confirmed by single-crystal X-ray diffraction study. In our study, we investigated synthesis, structural characterization, antimicrobial, anti-biofilm, and anti-cancer activity, and plausible mechanism of action of a novel mononuclear copper(II) schiff base complex. Increasing microbial resistance to several commercially available or traditional antimicrobial compounds has become a major global health concern at present time. The mononuclear copper(II) complex exhibited potential antibacterial activity against two strains of the gram-negative pathogen Pseudomonas aeruginosa. The copper compound dependent damage of bacterial cell membrane and inhibition of bacterial biofilm formation were also identified. Moreover, complex 1 inhibited prostate cancer cell growth, and migration by inducing apoptosis and arresting the cell cycle at the G2/M phase. Based on the results, we are suggesting our novel mononuclear copper(II) compound as a potential candidate for the development of new antibacterial and anti-cancer drugs.

4-Thiazolidinone Based 5-Arylidene Hybrids: Design, Synthesis, Antimicrobial Activity, and Molecular Docking Studies

In recent years, the most pressing challenge in drug development has been the fight against bacterial drug resistance. Microbes have developed resistance against the present classes of antibiotics, necessitating the development of new antibiotics capable of replacing less effective drugs commercially accessible in the market. In order to achieve this, a straightforward technique for the synthesis of 4-thiazolidinone-based pyrazole-pyridine hybrids was designed (5a–o). The hybrids were characterized using spectroscopic techniques and tested for antimicrobial efficacy against a variety of bacterial and fungal species. The MIC value of compounds 5d, 5f, 5j, 5 l, 5 m, and 5o against tested bacterial strains was 62.5 μg/mL. Compound 5i showed a MIC value of 250 μg/mL against Candida albicans, which is twice the activity of the standard drug. Furthermore, to rationalize the antimicrobial finding and to gain an insight into the plausible mechanism of action, molecular docking study was performed against microbial DNA gyrase. A very significant correlation obtained between the in silico binding affinity and the antimicrobial activity could set an excellent platform for structure based drug design.

Long noncoding RNA00324 is involved in the inflammation of rheumatoid arthritis by targeting miR-10a-5p via the NF-κB pathway.

Altered expressions of genes in immune cells and synovial tissues are involved in the pathology of rheumatoid arthritis (RA). Long noncoding RNAs act as competing endogenous RNAs and can cause immune disorders. The goal of this study was to reveal the association between noncoding RNA linc00324 and RA, and a plausible action mechanism was proposed. RT-qPCR was used to evaluate the expression of linc00324 in peripheral blood mononuclear cellsisolated from 50 RA patients and 50 healthy controls, and the correlations between linc00324 level and the clinical indicators were analyzed. Flow cytometry was used to characterize CD4+ T cells. The effects of linc00324 on cytokine production and cell proliferation of CD4+ T cells were evaluated by ELISA assay and Western blot. The interaction between linc00324 and miR-10a-5p was investigated by RNA immunoprecipitationand dual-luciferase assays. The linc00324 expression was significantly enhanced in RA patients, and linc00324 expression was positively correlated with rheumatoid factor and CD4+ T cells. Overexpression of linc00324 promoted CD4+ T cells proliferation, and enhanced chemokine MIP-1α secretion and NF-κB phosphorylation level, whereas knockout of linc00324 blocked CD4+ T cell proliferation and NF-κB phosphorylation. Overexpression of miR-10a-5p led to the decrease of CD4+ T cells proliferation and NF-κB phosphorylation, and reversed the effects of linc00324 on cell proliferation and NF-κB activity. Linc00324 was upregulated in RA and may exaggerate inflammation by targeting miR-10a-5p through NF-κB signaling pathway.

Discovery of PIM-1 kinase inhibitors based on the 2,5-disubstituted 1,3,4-oxadiazole scaffold against prostate cancer: Design, synthesis, in vitro and in vivo cytotoxicity investigation

PIM-1 kinases play an established role in prostate cancer development and progression. This research work tackles the design and synthesis of new PIM-1 kinase targeting 2,5-disubstituted-1,3,4-oxadiazoles 10a-g&11a-f, and investigation thereof as potential anti-cancer agents through in vitro cytotoxicity assay followed by in vivo studies along with exploration of this chemotype's plausible mechanism of action. In vitro cytotoxicity experiments have disclosed 10f as the most potent derivative against PC-3 cells (IC50 = 16 nM) compared to the reference drug Staurosporine (IC50 = 0.36 μM), also eliciting good cytotoxicity against HepG2 and MCF-7 cells (IC50 = 0.13 and 5.37 μM, respectively). Investigating PIM-1 kinase inhibitory activity of compound 10f revealed an IC50 of 17 nM paralleled to that of Staurosporine (IC50 = 16.7 nM). Furthermore, compound 10f displayed an antioxidant activity eliciting a DPPH inhibition ratio of 94% as compared to Trolox (96%). Further investigation demonstrated that 10f induced apoptosis in treated PC-3 cells by 43.2-fold (19.44%) compared to 0.45% in control. 10f also disrupted the PC-3 cell cycle by increasing the cell population at the PreG1-phase by 19.29-fold while decreasing the G2/M-phase by 0.56-fold compared to control. Moreover, 10f affected a downregulation of JAK2, STAT3 and Bcl-2 and upregulation of caspases 3, 8 and 9 levels that activated the caspase-dependent apoptosis. Finally, in vivo 10f-treatment caused a significant increase in tumor inhibition by 64.2% compared to 44.5% in Staurosporine treatment of the PC-3 xenograft mouse model. Additionally, it improved the hematological, biochemical parameters, and histopathological examinations compared to control untreated animals. Finally, docking of 10f with the ATP-binding site of PIM-1 kinase demonstrated good recognition of and effective binding to the active site. In conclusion, compound 10f represents a promising lead compound that merits further future optimization for controlling prostate cancer.

Synthesis of novel 6-substituted-3-formyl chromone derivatives as anti-leishmanial agents and their possible mechanism of action in Leishmania donovani

Eleven new compounds, including the hydrazones 4a-h, pyrazole 5, and pyrazole-oximes 7b-c, were synthesized by condensation reaction between 6-substituted (-H, -Me, -F) 3-formylchromones 1a-c with N-substituted hydrazines 2a-d and hydroxylamine hydrochloride 3. The synthesized compounds were evaluated for their in vitro antileishmanial activity to determine the IC50 values. Compounds 4b, 4c and 4e exhibited the strongest antileishmanial activity with IC50 values between 1.6 – 4.7 µm. A plausible mechanism of action is proposed for the antileishmanial activity of the above-mentioned compounds. We also studied the effect of these three compounds on macrophages, which represent the mammalian host-cell. The results obtained on this system were about one order of magnitude larger when compared to those of L. donovani, thus supporting these compounds potential as precursors of antileishmanial drugs.

Antimycobacterial Compound of Cynoglossum lanceolatum Forsk.: Bioassay Guided Isolation, Molecular Docking, Synthesis of Analogs, and a Plausible Mechanism of Action.

Tuberculosis (TB) remains a major threat to human health. Due to the prevalence of drug-resistant Mycobacterium tuberculosis (Mtb), it is urgent to discover drugs with new mechanisms of action (MOA) to ensure effectiveness against strains that are resistant to existing TB drugs. Cynoglossum lanceolatum Forsk was used to treat TB in Traditional Chinese Medicine. In this article, shikonin, the anti-Mtb active component, was obtained from the whole herb extract of C. lanceolatum by bioassay-guided isolation. Using the microplate alamar blue assay (MABA), the minimum inhibitory concentration (MIC) of shikonin against Mtb was determined to be 128 μg/mL. In order to obtain a more efficient anti-Mtb molecule, (E)-1-(6-bromo-2,3-dihydrochromen-4-ylidene)thiosemicarbazide was synthesized based on the scaffold of shikonin, which exhibited potent activity against Mtb (MIC=4 μg/mL). These results highlight that both naphthalene-1,4-dione and chroman-4-one are pharmacophores with activities against Mtb. To investigate a plausible mechanism of action, the molecular docking was firstly performed against catalase-peroxidase enzyme (KatG) of Mtb using AutoDock 4 software. The results demonstrated that both shikonin and (E)-1-(6-bromo-2,3-dihydrochromen-4-ylidene)thiosemicarbazide could bind to the active site of Mtb KatG. KatG enzyme activity and intracellular reactive oxygen species (ROS) levels in Mtb cells were then measured by ultraviolet spectrophotometric method and fluorescence microplate reader assay, respectively. The experiments confirmed that above compounds could inhibit the catalytic activity of Mtb KatG, and cause the ROS accumulation in Mtb cells. Therefore, inhibition of KatG may be a novel mechanism of action for these two compounds to fight against Mtb.

Antihypertensive effects of pentacyclic triterpenoid from Convolvulus pluricaulis and its plausible mechanism of action hypothesizing its selectivity targeting Mineralocorticoid receptor of RAAS.

BackgroundThe renin-angiotensin-aldosterone system (RAAS) is important in maintaining blood pressure and malfunction of this system leads to the main cause of hypertension. Though a variety of synthetic inhibitors have been used to treat hypertension and related disorders, chronic use of these inhibitors causes undesirable side effects. To eliminate this problem, several scientific studies have proved that plant based and food derived products could be used as an alternative strategy to treat high blood pressure. PurposeWe intend to isolate the major bioactive compound from the medicinal plant Convolvulus pluricaulis as it is reported to possess anti-hypertensive activity. We also aimed to address the mechanism of action of taraxerol and to hypothesize its selectivity targeting RAAS. Study designThe study was designed to isolate the phytoconstituent from C. pluricaulis and characterization by XRD, NMR, FT-IR, and UV–Vis. To further elucidate the activity of isolated molecules, we have designed a two-way approach using in-silico and in-vitro methodologies. MethodsThe roots of Convolvulus pluricaulis were dried, powdered and the extract was purified by repeated column chromatography. The purified compound was characterized by UV–Vis, IR, NMR, and single crystal X-ray diffraction. The high quality single crystal was grown from the mixture of hexane ethyl acetate. Molecular docking was done to identify the interaction pattern and binding efficacy of isolated compounds against various receptors of RAAS and the stability of the molecule was analyzed by molecular dynamic simulations. The cytotoxicity of the molecule was checked using the MTT assay and the IC50 value was also calculated against the AngII-induced cardiac hypertrophy in H9c2 cells. Tanimoto coefficient was calculated to check the similarity indices with the already reported antihypertensives from plants/herbs. ResultsThe crystal structure of taraxerol solved by crystallography has been deposited with the Cambridge Crystallographic Data Centre (CCDC: 2,180,265). Taraxerol had an IC50 at 20 μM concentration against AngII-induced cardiac hypertrophy in H9c2 cells, indicating that it suggestively increased the cell viability as compared to positive control. In-silico molecular docking analysis of taraxerol found that taraxerol binds to mineralocorticoid receptor with the binding energy of −11.03 kcal/mol. Molecular Dynamics (MD) simulations were further done to check the stability of MR-taraxerol complex to unravel the structure activity relationship of taraxerol. Furthermore, SAR studies show that taraxerol had the highest degree of molecular similarity (0.78% – 0.93%) with reported antihypertensive oleanane triterpenoids highlighting its efficacy. ConclusionOur findings corroborate taraxerol as a potential anti-hypertensive agent and leads to the hypothesis of its specificity towards Mineralocorticoid receptor than other receptors in RAAS.

Glycyrrhizin prevents 3-nitropropionic acid-induced neurotoxicity by downregulating HMGB1/TLR4/NF-κB p65 signaling, and attenuating oxidative stress, inflammation, and apoptosis in rats

AimsGlycyrrhizin (Glyc) is a saponin triterpenoid that has signified its efficacy against Huntington's disease (HD). Nonetheless, its mechanism has not been fully clarified. Accordingly, this study was designed to evaluate the plausible mechanism of action of Glyc against 3-nitropropionic acid (3-NP)-induced HD. Main methodsRats were treated with Glyc (50 mg/kg, i.p.) for 3 weeks and 3-NP (10 mg/kg, i.p.) was administered at the latter 2 weeks alongside to induce HD. Key findingsAnimals exposed to 3-NP revealed a reduction in body weight, neurobehavioral abnormalities, and various deleterious effects related to overexpression of HMGB1 such as oxidative stress, apoptosis, and inflammation. Promisingly, Glyc administration provided valuable effects by reversing the decline in body weight with improved neurobehavioral deficits. Ameliorating oxidative stress via restoring GSH, SOD, and Nrf2 alongside with MDA suppression was evident. Furthermore, Glyc switched the HMGB1/TLR4/NF-κB p65 signaling off, reduced IL-6, IL-β, TNF-α, caspase-3, and increased Bcl-2 as well as BDNF. All these beneficial effects were mirrored by a better histopathological picture upon using Glyc that suppressed gliosis by reducing GFAP expression as observed in the immunohistochemistry results. SignificanceAccordingly, the current study demonstrated a promising neuroprotective effect of Glyc against experimentally induced HD through alleviating deleterious events by diverse mechanisms.