Synthesis, spectroscopic characterization, DFT calculations, in silico-ADMET and molecular docking analysis of novel quinoline-substituted 5H-chromeno [2,3-b] pyridine derivatives as antibacterial agents.

A convenient, straightforward, and effective one-step reaction for the synthesis of a three-component compound of biologically relevant novel 2,4-diamino-5-(8-hydroxyquinolin-7-yl)-5H-chromeno[2,3-b] pyridine-3-carbonitrile derivatives was designed and synthesized. The synthesis was developed by the reaction between salicylaldehyde 1, 8-hydroxyquinoline 2, 2-aminopropene-1,1,3-tricarbonitrile 3, and the catalytic amount of triethylamine in ethanol at 78 °C. This methodology has many beneficial features, including the use of inexpensive and non-hazardous starting materials, single-flask reactions, optimized reaction conditions, the termination of intermediate isolation, easy workup, reducing organic waste products, being chromatography-free, and decreasing the reaction time along with quantitative yields with high functional group tolerance. A proposed mechanism with supporting experimental data is presented, including 1H NMR, 13C NMR, 2D NMR (HMBC, COSY, HSQC), mass, and IR spectroscopy, which are used to characterize the complete derivatives. All synthesized compounds were evaluated in vitro for their antibacterial activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacterial strains via the agar-well diffusion method compared with the reference drug gentamicin. The data indicated that compounds 4A, 4F, 4G, 4 J, and 4K consistently demonstrated strong antimicrobial activity against Gram-positive and Gram-negative bacteria. Furthermore, a molecular docking investigation was carried out to gain insight into the binding mode of the most promising compounds via the crystal structure of the S. aureus DNA gyrase complex with ciprofloxacin (PDB ID: 2XCT). Density functional theory (DFT) calculations were performed to determine the various molecular properties of the synthesized novel 2,4-diamino-5-(8-hydroxyquinolin-7-yl)-5H-chromeno [2,3-b] pyridine-3-carbonitrile derivatives (4A-4 M). On the basis of the reactive sites explored by the molecular electrostatic potential maps, the antibacterial activities of the compounds were screened.

Explore new quinoxaline pharmacophore tethered sulfonamide fragments as in vitro α-glucosidase, α-amylase, and acetylcholinesterase inhibitors with ADMET and molecular modeling simulation.

A new series of quinoxaline-sulfonamide derivatives 3-12 were synthesized using fragment-based drug design by reaction of quinoxaline sulfonyl chloride (QSC) with different amines and hydrazines. The quinoxaline-sulfonamide derivatives were evaluated for antidiabetic and anti-Alzheimer's potential against α-glucosidase, α-amylase, and acetylcholinesterase enzymes. These derivatives showed good to moderate potency against α-amylase and α-glucosidase with inhibitory percentages between 24.34 ± 0.01%-63.09 ± 0.02% and 28.95 ± 0.04%-75.36 ± 0.01%, respectively. Surprisingly, bis-sulfonamide quinoxaline derivative 4 revealed the most potent activity with inhibitory percentages of 75.36 ± 0.01% and 63.09 ± 0.02% against α-glucosidase and α-amylase compared to acarbose (IP = 57.79 ± 0.01% and 67.33 ± 0.01%), respectively. Moreover, the quinoxaline derivative 3 exhibited potency as α-glucosidase and α-amylase inhibitory with a minute decline from compound 4 and acarbose with inhibitory percentages of 44.93 ± 0.01% and 38.95 ± 0.01%. Additionally, in vitro acetylcholinesterase inhibitory activity for designed derivatives exhibited weak to moderate activity. Still, sulfonamide-quinoxaline derivative 3 emerged as the most active member with inhibitory percentage of 41.92 ± 0.02% compared with donepezil (IP = 67.27 ± 0.60%). The DFT calculations, docking simulation, target prediction, and ADMET analysis were performed and discussed in detail.

Isoxazole carboxylic acid methyl ester-based urea and thiourea derivatives as promising antitubercular agents.

In our continued efforts to find potential chemotherapeutics active against drug-resistant (DR) Mycobacterium tuberculosis (Mtb), causative agent of Tuberculosis (TB) and to curb the current burdensome treatment regimen, herein we describe the synthesis and biological evaluation of urea and thiourea variants of 5-phenyl-3-isoxazolecarboxylic acid methyl esters as promising anti-TB agent. Majority of the tested compounds displayed potent in vitro activity not only against drug-susceptible (DS) Mtb H37Rv but also against drug-resistant (DR) Mtb. Cell viability test against Vero cells deemed these compounds devoid of significant toxicity. 3,4-Dichlorophenyl derivative (MIC 0.25 µg/mL) and 4-chlorophenyl congener (MIC 1 µg/mL) among urea and thiourea libraries respectively exhibited optimum potency. Lead optimization resulted in the identification of 1,4-linked analogue of 3,4-dichlorophenyl urea derivative demonstrating improved selectivity. Further, in silico study complemented with previously proposed prodrug like attributes of isoxazole esters. Taken together, this molecular hybridization approach presents a new chemotype having potential to be translated into an alternate anti-Mtb agent.

In vitro enzymatic evaluation of some pyrazolo[1,5-a]pyrimidine derivatives: Design, synthesis, antioxidant, anti-diabetic, anti-Alzheimer, and anti-arthritic activities with molecular modeling simulation.

The strategy of utilizing nitrogen compounds in various biological applications has recently emerged as a powerful approach to exploring novel classes of therapeutics to face the challenge of diseases. A series of pyrazolo[1,5-a]pyrimidine-based compounds 3a-l and 5a-f were prepared by the direct cyclo-condensation reaction of 5-amino-1H-pyrazoles 1a, b with 2-(arylidene)malononitriles and 3-(dimethylamino)-1-aryl-prop-2-en-1-ones, respectively. The structures of the new pyrazolo[1,5-a]pyrimidine compounds were confirmed via spectroscopic techniques. The in vitro biological activities of all pyrazolo[1,5-a]pyrimidines 3a-l and 5a-f were evaluated by assaying total antioxidant capacity, iron-reducing power, the scavenging activity against 1-diphenyl-2-picryl-hydrazyl (DPPH) and 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, anti-diabetic, anti-Alzheimer, and anti-arthritic biological activities. All compounds displayed good to potent bioactivity, and three compounds 3g, 3h, and 3l displayed the most active derivatives. Among these derivatives, compound 3l exhibited the highest antioxidant (total antioxidant capacity [TAC] = 83.09 mg gallic acid/g; iron-reducing power [IRP] = 47.93 µg/ml) and free radicals scavenging activities with (DPPH = 18.77 µg/ml; ABTS = 40.44%) compared with ascorbic acid (DPPH = 4.28 µg/ml; ABTS = 38.84%). Furthermore, compound 3l demonstrated the strongest inhibition of α-amylase with a percent inhibition of 72.91 ± 0.14 compared to acarbose = 67.92 ± 0.09%. Similarly, it displayed acetylcholinesterase inhibition of 62.80 ± 0.06%. However, compound 3i showed a significantly higher inhibition percentage for protein denaturation and proteinase at 20.66 ± 0.00 and 26.42 ± 0.06%, respectively. Additionally, some in silico ADMET properties were predicted and studied. Finally, molecular docking simulation was performed inside the active site of α-amylase and acetylcholinesterase to study their interactions.

Unveiling the Anti-Cancer Potential of Onoceranoid Triterpenes from Lansium domesticum Corr. cv. kokosan: An In Silico Study against Estrogen Receptor Alpha.

Breast cancer is a significant global concern, with tamoxifen, the standard treatment, raising long-term safety issues due to side effects. In this study, we evaluated the potential of five onoceranoid triterpenes from Lansium domesticum Corr. cv. kokosan against estrogen receptor alpha (ERα) using in silico techniques. Utilizing molecular docking, Lipinski's rule of five, in silico ADMET, and molecular dynamics simulations, we assessed the potency of five onoceranoid triterpenes against ERα. Molecular docking indicated competitive binding energies for these triterpenes relative to the active form of tamoxifen (4OHT) and estradiol, an ERα native ligand. Three triterpenes met drug-likeness criteria with favorable ADMET profiles. Notably, 2 demonstrated superior binding affinity in molecular dynamics simulations, outperforming estradiol, closely followed by 3 and 4. Hierarchical clustering on principal components (HCPC) and the spatial distribution of contact surface area (CSA) analyses suggest that these triterpenes, especially 2, may act as antagonist ligands akin to 4OHT. These findings highlight the potential of onoceranoid triterpenes in treating ERα-related breast cancer.

Unraveling the Pharmaceutical Benefits of Freshly Prepared Amino Acid-Based Schiff Bases Via DFT, In Silico Molecular Docking and ADMET.

A series of amino acid-based Schiff bases have been synthesized using a facile condensation between benzil (a diketone) and amino acid in the presence of a base. The formation of Schiff base compounds has been ensured by elemental analysis, FT-IR, 1H-NMR, 13C-NMR and UV-Vis. spectra. Density Functional Theory (DFT) calculations have been explored in order to get intuition into the molecular structure and chemical reactivity of the compounds. The DFT, optimized structure of the compounds, has been used to attain the molecular docking studies with DNA structure to find the favorable mode of interaction. In silico ADME/Tox profile of the compounds has been predicted using pkCSM web tools, exhibiting suitable values of absorption, distribution, and metabolism. These obtained parameters are connected to bioavailability. In addition, toxicity, skin sensitization and cardiotoxicity (hERG) analysis have been performed for evaluating the drug-like character of the prepared Schiff bases. The findings obtained from this study may find applications in the field focusing on the production of efficient and harmless pharmacological drugs.

A New Xanthone Glycoside from Mangifera indica L.: Physicochemical Properties and In Vitro Anti-Skin Aging Activities.

A new xanthone glycoside, 1,3,5,6-tetrahydroxyxanthone-C-4-ß-d-glucopyranoside was isolated from the methanol extract of Mangifera indica leaves (Anacardiaceae) growing in Egypt. The structure was clarified by 1D and 2D-NMR spectroscopic data. The physicochemical properties of the compound such as lipophilicity, solubility, and formulation considerations were predicted via in silico ADMET technique using the SwissADME server. This technique provided Lipinski's rule of five, such as GIT absorption, distribution, metabolism, and skin permeation. The in vitro inhibitory activities against aging-mediated enzymes such as collagenase, elastase, hyaluronidase, and tyrosinase were assessed. The compound exhibited remarkable anti-collagenase, anti-elastase, anti-hyaluronidase, and anti-tyrosinase effects with IC50 values of 1.06, 419.10, 1.65, and 0.48 µg/mL, respectively, compared to the positive control. The compound showed promising predicted aqueous solubility and reasonable skin penetration suggesting the suitability of the compound for topical formulation as an anti-aging agent for cosmetic preparations.

Novel phenanthridine amide analogs as potential anti-leishmanial agents: In vitro and in silico insights.

In the current work, sixteen novel amide derivatives of phenanthridine were designed and synthesized using 9-fluorenone, 4-Methoxy benzyl amine, and alkyl/aryl acids. The characterization of the title compounds was performed using LCMS, elemental analysis, 1HNMR, 13CNMR and single crystal XRD pattern was also developed for compounds A8. All the final analogs were screened in vitro for anti-leishmanial activity against promastigote form of L. infantum strain. Among the tested analogs, four compounds (A-06, A-11, A-12, and A-15) exhibited significant anti-leishmanial activity with EC50 value ranges from 8.9 to 21.96 µM against amastigote forms of tested L. infantum strain with SI ranges of 1.0 to 4.3. From the activity results it was found that A-11 was the most active compound in both promastigote and amastigotes forms with EC50 values 8.53 and 8.90 µM respectively. In-silico ADME prediction studies depicted that the titled compounds obeyed Lipinski's rule of five as that of the approved marketed drugs. The predicted in-silico toxicity profile also confirmed that the tested compounds were non-toxic. Finally, molecular docking and molecular dynamics study was also performed for significantly active compound (A-11) in order to study it's putative binding pattern at the active site of the selected leishmanial trypanothione reductase target as well as to understand the stability pattern of target-ligand complex for 100 ns. Single crystal XRD of compound A-08 revealed that the compound crystallizes in monoclinic C2/c space group and showed interesting packing arrangements.

In Vitro Phenotypic Activity and In Silico Analysis of Natural Products from Brazilian Biodiversity on Trypanosoma cruzi.

Chagas disease (CD) affects more than 6 million people worldwide. The available treatment is far from ideal, creating a demand for new alternative therapies. Botanical diversity provides a wide range of novel potential therapeutic scaffolds. Presently, our aim was to evaluate the mammalian host toxicity and anti-Trypanosoma cruzi activity of botanic natural products including extracts, fractions and purified compounds obtained from Brazilian flora. In this study, 36 samples of extracts and fractions and eight pure compounds obtained from seven plant species were evaluated. The fraction dichloromethane from Aureliana fasciculata var. fasciculata (AFfPD) and the crude extract of Piper tectoniifolium (PTFrE) showed promising trypanosomicidal activity. AFfPD and PTFrE presented EC50 values 10.7 ± 2.8 µg/mL and 12.85 ± 1.52 µg/mL against intracellular forms (Tulahuen strain), respectively. Additionally, both were active upon bloodstream trypomastigotes (Y strain), exhibiting EC50 2.2 ± 1.0 µg/mL and 38.8 ± 2.1 µg/mL for AFfPD and PTFrE, respectively. Importantly, AFfPD is about five-fold more potent than Benznidazole (Bz), the reference drug for CD, also reaching lower EC90 value (7.92 ± 2.2 µg/mL) as compared to Bz (23.3 ± 0.6 µg/mL). Besides, anti-parasitic effect of eight purified botanic substances was also investigated. Aurelianolide A and B (compounds 1 and 2) from A. fasciculata and compound 8 from P. tuberculatum displayed the best trypanosomicidal effect. Compounds 1, 2 and 8 showed EC50 of 4.6 ± 1.3 µM, 1.6 ± 0.4 µM and 8.1 ± 0.9 µM, respectively against intracellular forms. In addition, in silico analysis of these three biomolecules was performed to predict parameters of absorption, distribution, metabolism and excretion. The studied compounds presented similar ADMET profile as Bz, without presenting mutagenicity and hepatotoxicity aspects as predicted for Bz. Our findings indicate that these natural products have promising anti-T. cruzi effect and may represent new scaffolds for future lead optimization.

Synthesis, Biological Activity and Preliminary in Silico ADMET Screening of Polyamine Conjugates with Bicyclic Systems.

Polyamine conjugates with bicyclic terminal groups including quinazoline, naphthalene, quinoline, coumarine and indole have been obtained and their cytotoxic activity against PC-3, DU-145 and MCF-7 cell lines was evaluated in vitro. Their antiproliferative potential differed markedly and depended on both their chemical structure and the type of cancer cell line. Noncovalent DNA-binding properties of the most active compounds have been examined using ds-DNA thermal melting studies and topo I activity assay. The promising biological activity, DNA intercalative binding mode and favorable drug-like properties of bis(naphthalene-2-carboxamides) make them a good lead for further development of potential anticancer drugs.

Synthesis and Pharmacological Evaluation of Novel 1-(1,4-Alkylaryldisubstituted-4,5-dihydro-1H-imidazo)-3-substituted Urea Derivatives.

Novel 1-(1,4-alkylaryldisubstituted-4,5-dihydro-1H-imidazo)-3-substituted urea derivatives have been synthesized and evaluated for their central nervous system activity. Compounds 3a-m were prepared in the reaction between the respective 1-alkyl-4-aryl-4,5-dihydro-1H-imidazol-2-amines 1a-c and appropriate isocyanates 2 in dichloromethane. The compounds were subjected to in silico ADMET studies in order to select best candidates for in vivo experiments. The effects of the compounds on the spontaneous locomotor activity and amphetamine-evoked hyperactivity were estimated. Analgesic activity, without or in the presence of naloxone, was assessed in the writhing test. The tendency to change the HTR, evoked by l-5-HTP and the involvement in alteration in body temperature in mice was studied. Additionally, to check possible occurrence of drug-induced changes in the muscle relaxant activity of mice, which may have contributed to their behaviour in other tests, the rota-rod and chimney tests were performed. The new urea derivatives exerted significant activities in the performed pharmacological tests, although the presented results show a preliminary estimation, and thus, need to be extended for identification and understanding the complete pharmacological profile of the examined compounds.

Novel derivatives of nitro-substituted salicylic acids: Synthesis, antimicrobial activity and cytotoxicity.

Inspired by the high antituberculous activity of novel nitro-substituted derivatives and based on promising predicted ADMET properties we have synthesized a series of 33 salicylanilides containing nitro-group in their salicylic part and evaluated them for their in vitro antimycobacterial, antimicrobial and antifungal activities. The presence of nitro-group in position 4 of the salicylic acid was found to be beneficial and the resulting molecules exhibited minimum inhibitory concentrations (MICs) ranging from 2 to 32 µM against Mycobacterium tuberculosis. The best activity was found for 2-hydroxy-4-nitro-N-[4-(trifluoromethyl)phenyl]benzamide (MIC=2 µM). 4-Nitrosalicylanilides were also found to be active against all Staphylococcus species tested while for MRSA strain 2-hydroxy-4-nitro-N-[4-(trifluoromethyl)phenyl]benzamide's MIC was 0.98 µM. None of the nitrosalicylanilides was active against Enterococcus sp. J 14365/08 and no considerable activity was found against Gram-negative bacteria or fungi. The hepatotoxicity of all nitrosalicylanilides was found to be in the range of their MICs for HepG2 cells.

Pyridazine Derivatives: Molecular Docking, ADMET Prediction, and Synthesis for Antihypertensive Activity.

INTRODUCTION: The drug discovery and development domain has witnessed remarkable advancements due to the integration of computational methods, particularly Computer-Aided Drug Design (CADD). Discovering and creating new drugs involves structural modifications to enhance their effectiveness and physical attributes. This frequently includes employing semisynthetic techniques to investigate structure-activity relationships thoroughly. Noticeable progress in molecular biology, computational chemistry, combinatorial chemistry, and highthroughput screening is steering transformative changes in the pharmaceutical industry. BACKGROUND: High blood pressure or hypertension, a significant health issue, elevates the chances of heart, kidney, and brain complications, among other health concerns. It's a leading cause of untimely mortality globally. Therefore, it is important to search for new antihypertensive compounds that have fewer side effects and higher therapeutic activity. METHODS: Following molecular docking of the pyridazine derivatives, compounds were subjected to In-silico ADMET analysis. Subsequently, a low molecular weight compound was synthesized. Among the synthesized compounds characterization procedures include TLC, FT-IR, 1HNMR, and LC-MS techniques. RESULT: Compound 8 exhibited the most favorable molecular docking results with alpha A1 and beta 1 adrenergic receptors. Compounds 3, 5, and 6 fulfilled the essential ADMET criteria. Subsequently, Compounds 3, 4, and 5 underwent additional synthesis and characterization procedures, including TLC, FT-IR, 1H-NMR, and LC-MS techniques. CONCLUSION: Similar behavior was observed in compounds 6, 8, 10, and 11, all violating Pfizer's 3/75 rules in terms of TPAS. Hydrazinolysis of these b-benzoyl propionic acids produced pyridazine, which was utilized in synthesizing pyridazine derivatives. TLC, FT-IR, 1HNMR, and LCMS have characterized the compounds.

Facile one-pot synthesis and in silico study of new heterocyclic scaffolds with 4-pyridyl moiety: Mechanistic insights and X-ray crystallographic elucidation.

4-Acetylpyridine 1 and malononitrile 2 were allowed to react in a 3MCRs with dimedone 3a or cyclohexa-1,3-dione 3b under reflux to afford 4-methyl-4-(pyridin-4-yl)-5,6,7,8-tetrahydro-4H-chromene derivatives 4a,b respectively. The mechanism of the reaction has been studied and the structures elucidated by analytical, spectral as well as X-ray crystallographic data. Heterocyclic compounds find widespread application in pharmaceutical and agrochemical products. Docking analyses were performed on the synthesized compounds to assess their binding modes with various amino acids of the target protein tubulin (PDB Code - 1SA0). The results indicated promising binding scores for compounds 4a and 4b, suggesting a strong affinity for the tubulin binding site. Finally, ADMET for the synthesized compounds 4a, 4b, 5, 8a and 8b were carried out. The drug likeness and pharmacokinetic properties of the prepared compounds were also evaluated. Notably, all of the novel compounds adhered to Lipinski's rule (Ro5) without any violations.

Novel (±)-trans-ß-lactam ureas: Synthesis, in silico and in vitro biological profiling.

A diastereomeric mixture of racemic 3-phthalimido-b-lactam 2a/2b was synthesized by the Staudinger reaction of carboxylic acid activated with 2-chloro-1-methylpyridinium iodide and imine 1. The amino group at the C3 position of the b-lactam ring was used for further structural upgrade. trans-b-lactam ureas 4a-t were prepared by the condensation reaction of the amino group of b-lactam ring with various aromatic and aliphatic isocyanates. Antimicrobial activity of compounds 4a-t was evaluated in vitro and neither antibacterial nor antifungal activity were observed. Several of the newly synthesized trans-b-lactam ureas 4a-c, 4f, 4h, 4n, 4o, 4p, and 4s were evaluated for in vitro antiproliferative activity against liver hepatocellular carcinoma (HepG2), ovarian carcinoma (A2780), breast adenocarcinoma (MCF7) and untransformed human fibroblasts (HFF1). The b-lactam urea 4o showed the most potent antiproliferative activity against the ovarian carcinoma (A2780) cell line. Compounds 4o and 4p exhibited strong cytotoxic effects against human non-tumor cell line HFF1. The b-lactam ureas 4a-t were estimated to be soluble and membrane permeable, moderately lipophilic molecules (logP 4.6) with a predisposition to be CYP3A4 and P-glycoprotein substrates. The tools PASS and SwissTargetPrediction could not predict biological targets for compounds 4a-t with high probability, pointing to the novelty of their structure. Considering low toxicity risk, molecules 4a and 4f can be selected as the most promising candidates for further structure modifications.

Design, synthesis and anti-Tb evaluation of chalcone derivatives as novel inhibitors of InhA.

A series of halogenated chalcone derivatives were designed and developed for anti-tubercular activity. Novel molecules were designed and in-silico screening were performed using admetSAR, SwissADME, and Osiris Property Explorer. From the initial filter the top 10 compounds were docked using the Autodock tool 1.5.6. and the binding energies of the docked compounds were higher than the standard drugs Isoniazid.and Ethionamide. Based on the in-silico and docking results, the top halogenated chalcones were synthesized and characterized using FT-IR, mass spectrometry, 1H, and 13C NMR spectroscopy. The chalcones were further evaluated for anti-tubercular activity using MABA against the H37Rv strain. Among the series of compounds, DK12 and DK14 showed potent in-vitro activity, with MICs of 0.8 µg/ml, in comparison with 1.6 µg/ml of the first-line drug Isoniazid. Further molecular dynamics simulations studies for 100 ns revealed that the key interaction with TYR 158 were observed in both DK12 and DK14 in the InhA active site. The compound DK12 further showed significant interactions with PHE 149 and ARG 153 residues and is a hit molecule among the series. Further DK12 and DK14 does not show any significance toxicity. The compounds DK12 needs to be optimized and further investigation to be carried out against InhA.Communicated by Ramaswamy H. Sarma.

Novel Eubacterium rectale inhibitor from Coriandrum sativum L. for possible prevention of colorectal cancer: a computational approach.

This research aims to screen out the effective bioactive compounds from Coriander (Coriandrum sativum L.), which may be novel potential inhibitors of Eubacterium rectale for the prevention of colorectal cancer (CRC). A series of 8 coriander-derived chemical compounds previously assessed for their anti-inflammatory, antioxidant, and antidiabetic activities were tested against Carbohydrate ABC transporter substrate-binding protein and compared to the standard inhibitor Acarbose, to support their use as novel Eubacterium rectale inhibitors. Herein, these derivatives were submitted to a thorough analysis of docking studies, in which detailed interactions of the selected phytocompounds with carbohydrate ABC transporter substrate-binding protein were revealed. Molecular docking analysis recommends Rutin, Gallocatechin, and Epigallocatechin as the most potential Eubacterium rectale inhibitors among the eight selected phytochemical compounds. Subsequently, the stability of the three selected phytochemical complexes was checked using molecular dynamics (MD) simulation at 100 ns and Molecular Mechanics combined with Poisson-Boltzmann Surface Area (MM-PBSA). The results show quite good stability for Rutin and Gallocatechin. In silico ADMET prediction was performed on the selected compounds, and the findings revealed a reasonably good ADMET profile for both Rutin and Gallocatechin. The current findings predict that Gallocatechin could be a better CRC preventive natural compound, and, further in vitro, in vivo and clinical studies may confirm its therapeutic potential.Communicated by Ramaswamy H. Sarma.

Antitumor activity against human promyelocytic leukemia and in silico studies of some benzoxazines.

Cancer is one of the deadliest diseases in the world today, and the incidence of cancer is increasing. Leukemia is a type of blood cancer defined as the uncontrolled proliferation of abnormal leukocytes in the blood and bone marrow. The HL-60 (human promyelocytic leukemia) cell line, derived from a single patient with acute promyelocytic leukemia, provides a unique in vitro model system for studying the cellular and molecular events involved in the proliferation and differentiation of leukemic cells. In this study, antitumor activities on the HL-60 of some of the resynthesized benzoxazine derivatives (BXN-01 and BXN-02) were investigated. The results of in vitro studies obtained were compared a standard drug, etoposide. In vitro results showed that BXN-01 and BXN-02 were found to be extremely effective compared to etoposide (IC50 value: 10 µM) with IC50 values of 5 nM and 25 nM, respectively. Furthermore, molecular docking studies were carried out for preliminary prediction of possible interaction modes between compounds and the active site of the target macromolecules, hTopo IIα, HDAC2, and RXRA. Then, in silico ADME/Tox studies were performed to predict drug-likeness and pharmacokinetic properties of BXN-01 and BXN-02.Communicated by Ramaswamy H. Sarma.

Natural polymers as potential P-glycoprotein inhibitors: Pre-ADMET profile and computational analysis as a proof of concept to fight multidrug resistance in cancer.

P-glycoprotein (P-gp) is known as the "multidrug resistance protein" because it contributes to tumor resistance to several different classes of anticancer drugs. The effectiveness of such polymers in treating cancer and delivering drugs has been shown in a wide range of in vitro and in vivo experiments. The primary objective of the present study was to investigate the inhibitory effects of several naturally occurring polymers on P-gp efflux, as it is known that P-gp inhibition can impede the elimination of medications. The objective of our study is to identify polymers that possess the potential to inhibit P-gp, a protein involved in drug resistance, with the aim of enhancing the effectiveness of anticancer drug formulations. The ADMET profile of all the selected polymers (Agarose, Alginate, Carrageenan, Cyclodextrin, Dextran, Hyaluronic acid, and Polysialic acid) has been studied, and binding affinities were investigated through a computational approach using the recently released crystal structure of P-gp with PDB ID: 7O9W. The advanced computational study was also done with the help of molecular dynamics simulation. The aim of the present study is to overcome MDR resulting from the activity of P-gp by using such polymers that can inhibit P-gp when used in formulations. The docking scores of native ligand, Agarose, Alginate, Carrageenan, Chitosan, Cyclodextrin, Dextran, Hyaluronic acid, and Polysialic acid were found to be -10.7, -8.5, -6.6, -8.7, -8.6, -24.5, -6.7, -8.3, and -7.9, respectively. It was observed that, Cyclodextrin possess multiple properties in drug delivery science and here also demonstrated excellent binding affinity. We propose that drug efflux-related MDR may be prevented by the use of Agarose, Carregeenan, Chitosan, Cyclodextrin, Hyaluronic acid, and/or Polysialic acid in the administration of anticancer drugs.

Antiparasitic Activity of Plumbago auriculata Extracts and Its Naphthoquinone Plumbagin against Trypanosoma cruzi.

Chagas disease (CD) caused by the protozoan Trypanosoma cruzi affects more than six million people worldwide. Treatment is restricted to benznidazole (Bz) and nifurtimox (Nf) that display low activity in the later chronic stage besides triggering toxic events that result in treatment abandonment. Therefore, new therapeutic options are necessary. In this scenario, natural products emerge as promising alternatives to treat CD. In the family Plumbaginaceae, Plumbago sp. exhibits a broad spectrum of biological and pharmacological activities. Thus, our main objective was to evaluate, in vitro and in silico, the biological effect of crude extracts of root and of aerial parts of P. auriculata, as well as its naphthoquinone Plumbagin (Pb) against T. cruzi. The phenotypic assays revealed potent activity of the root extract against different forms (trypomastigote and intracellular forms) and strains (Y and Tulahuen), with a compound concentration that reduced 50% of the number of the parasite (EC50) values ranging from 1.9 to 3.9 µg/mL. In silico analysis showed that Pb is predicted to have good oral absorption and permeability in Caco2 cells, besides excellent probability of absorption by human intestinal cells, without toxic or mutagenic potential effects, not being predicted as a substrate or inhibitor of P-glycoprotein. Pb was as potent as Bz against intracellular forms and displayed a superior trypanosomicidal effect (about 10-fold) in bloodstream forms (EC50 = 0.8 µM) as compared to the reference drug (8.5 µM). The cellular targets of Pb on T. cruzi were evaluated using electron microscopy assays and the findings on bloodstream trypomastigotes showed several cellular insults related to the autophagic process. Regarding toxicity in mammalian cells, the root extracts and the naphthoquinone present a moderate toxic profile on fibroblasts and cardiac cell lines. Then, aiming to reduce host toxicity, the root extract and Pb were tested in combination with Bz, and the data showed additive profiles with the sum of the fractional inhibitory concentration indexes (ΣFICIs) being 1.45 and 0.87, respectively. Thus, our work reveals the promising antiparasitic activity of Plumbago auriculata crude extracts and its purified naphthoquinone Plumbagin against different forms and strains of Trypanosoma cruzi in vitro.