Green synthesis and characterization of silver nanoparticles from Ducrosia flabellifolia Boiss. aqueous extract: Anti-quorum sensing screening and antimicrobial activities against ESKAPE pathogens.

Biosynthesis of silver nanoparticles using natural compounds derived from plant kingdom is currently used as safe and low-cost technique for nanoparticles synthesis with important abilities to inhibit multidrug resistant microorganisms (MDR). ESKAPE pathogens, especially MDR ones, are widely spread in hospital and intensive care units. In the present study, AgNPs using Ducrosia flabellifolia aqueous extract were synthesized using a reduction method. The green synthesized D. flabellifolia-AgNPs were characterized by UV-Vis spectrophotometer, Scanning electron microscopy (SEM), and X-ray diffraction assays. The tested D. flabellifolia aqueous extract was tested for its chemical composition using Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS). Anti-quorum sensing and anti-ESKAPE potential of D. flabellifolia-AgNPs was also performed.  Results from LC-ESI-MS technique revealed the identification of chlorogenic acid, protocatechuic acid, ferulic acid, caffeic acid, 2,5-dihydroxybenzoic acid, and gallic acid as main phytoconstituents. Indeed, the characterization of newly synthetized D. flabellifolia-AgNPs revealed spherical shape with mean particle size about 16.961±2.914 nm. Bio-reduction of silver was confirmed by the maximum surface plasmon resonance of D. flabellifolia-AgNPs at 430 nm. Newly synthetized D. flabellifolia-AgNPs were found to possess important anti-ESKAPE activity with low minimal inhibitory concentrations (MICs) ranging from 0.078 to 0.312 mg/mL, and low minimal bactericidal concentrations (MBCs) varying from 0.312 to 0.625 mg/mL. Moreover, D. flabellifolia-AgNPs were active against Candida utilis ATCC 9255, C. tropicalis ATCC 1362, and C. albicans ATCC 20402 with high mean diameter of growth inhibition at 5 mg/mL, low MICs, and minimal fungicidal concentrations values (MFCs). The newly synthetized D. flabellifolia-AgNPs were able to inhibit violacein production in Chromobacterium violaceum, pyocyanin in Pseudomonas aeruginosa starter strains.  Hence, the newly synthesized silver nanoparticles using D. flabellifolia aqueous extract can be used as an effective alternative to combat ESKAPE microorganisms. These silver nanoparticles can attenuate virulence of Gram-negative bacteria by interfering with the quorum sensing system and inhibiting cell-to-cell communication.

In Silico Design, Synthesis, and Evaluation of Novel Enantiopure Isoxazolidines as Promising Dual Inhibitors of α-Amylase and α-Glucosidase.

Isoxazolidine derivatives were designed, synthesized, and characterized using different spectroscopic techniques and elemental analysis and then evaluated for their ability to inhibit both α-amylase and α-glucosidase enzymes to treat diabetes. All synthesized derivatives demonstrated a varying range of activity, with IC50 values ranging from 53.03 ± 0.106 to 232.8 ± 0.517 µM (α-amylase) and from 94.33 ± 0.282 to 258.7 ± 0.521 µM (α-glucosidase), revealing their high potency compared to the reference drug, acarbose (IC50 = 296.6 ± 0.825 µM and 780.4 ± 0.346 µM), respectively. Specifically, in vitro results revealed that compound 5d achieved the most inhibitory activity with IC50 values of 5.59-fold and 8.27-fold, respectively, toward both enzymes, followed by 5b. Kinetic studies revealed that compound 5d inhibits both enzymes in a competitive mode. Based on the structure-activity relationship (SAR) study, it was concluded that various substitution patterns of the substituent(s) influenced the inhibitory activities of both enzymes. The server pkCSM was used to predict the pharmacokinetics and drug-likeness properties for 5d, which afforded good oral bioavailability. Additionally, compound 5d was subjected to molecular docking to gain insights into its binding mode interactions with the target enzymes. Moreover, via molecular dynamics (MD) simulation analysis, it maintained stability throughout 100 ns. This suggests that 5d possesses the potential to simultaneously target both enzymes effectively, making it advantageous for the development of antidiabetic medications.

Illicium verum L. (Star Anise) Essential Oil: GC/MS Profile, Molecular Docking Study, In Silico ADME Profiling, Quorum Sensing, and Biofilm-Inhibiting Effect on Foodborne Bacteria.

Illicium verum, or star anise, has many uses ranging from culinary to religious. It has been used in the food industry since ancient times. The main purpose of this study was to determine the chemical composition, antibacterial, antibiofilm, and anti-quorum sensing activities of the essential oil (EO) obtained via hydro-distillation of the aerial parts of Illicium verum. Twenty-four components were identified representing 92.55% of the analyzed essential oil. (E)-anethole (83.68%), limonene (3.19%), and α-pinene (0.71%) were the main constituents of I. verum EO. The results show that the obtained EO was effective against eight bacterial strains to different degrees. Concerning the antibiofilm activity, trans-anethole was more effective against biofilm formation than the essential oil when tested using sub-inhibitory concentrations. The results of anti-swarming activity tested against P. aeruginosa PAO1 revealed that I. verum EO possesses more potent inhibitory effects on the swarming behavior of PAO1 when compared to trans-anethole, with the percentage reaching 38% at a concentration of 100 µg/mL. The ADME profiling of the identified phytocompounds confirmed their important pharmacokinetic and drug-likeness properties. The in silico study using a molecular docking approach revealed a high binding score between the identified compounds with known target enzymes involved in antibacterial and anti-quorum sensing (QS) activities. Overall, the obtained results suggest I. verum EO to be a potentially good antimicrobial agent to prevent food contamination with foodborne pathogenic bacteria.

Tripeptides from Allium subhirsitum L. extracts: Pharmacokinetics properties, toxicity prediction and in silico study against SARS-CoV-2 enzymes and pro-inflammatory proteins.

Developing new prophylactic and therapeutic agents with broad-spectrum antiviral activities is urgently needed to combat emerging human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since no available clinically antiviral drugs have been approved to eradicate COVID-19 as of the writing of this report, this study aimed to investigate bioactive short peptides from Allium subhirsutum L. (Hairy garlic) extracts identified through HR-LC/MS analysis that could potentially hinder the multiplication cycle of SARS-CoV-2 via molecular docking study. The obtained promising results showed that the peptides (Asn-Asn-Asn) possess the highest binding affinities of -8.4 kcal/mol against S protein, (His-Phe-Gln) of -9.8 kcal/mol and (Gln-His-Phe) of -9.7 kcal/mol towards hACE2, (Thr-Leu-Trp) of -10.3 kcal/mol and (Gln-Phe-Tyr) of -9.8 kcal/mol against furin. Additionally, the identified peptides show strong interactions with the targeted and pro-inflammatory ranging from -8.1 to -10.5 kcal/mol for NF-κB-inducing kinase (NIK), from -8.2 to -10 kcal/mol for phospholipase A2 (PLA2), from -8.0 to -10.7 kcal/mol for interleukin-1 receptor-associated kinase 4 (IRAK-4), and from -8.6 to -11.6 kcal/mol for the cyclooxygenase 2 (COX2) with Gln-Phe-Tyr model seems to be the most prominent. Results from pharmacophore, drug-likeness and ADMET prediction analyses clearly evidenced the usability of the peptides to be developed as an effective drug, beneficial for COVID-19 treatment.

Repurposing of anisomycin and oleandomycin as a potential anti-(SARS-CoV-2) virus targeting key enzymes using virtual computational approaches.

Despite the accelerated emerging of vaccines, development against the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) drugs discovery is still in demand. Repurposing the existing drugs is an ideal time/cost-effective strategy to tackle the clinical impact of SARS CoV-2. Thereby, the present study is a promising strategy that proposes the repurposing of approved drugs against pivotal proteins that are responsible for the viral propagation of SARS-CoV-2 virus Angiotensin-converting enzyme-2 (ACE2; 2AJF), 3CL-protease: main protease (6LU7), Papain-like protease (6W9C), Receptor Binding Domain of Spike protein (6VW1), Transmembrane protease serine 2 (TMPRSS-2; 5AFW) and Furin (5MIM) by in silico methods. Molecular docking results were analyzed based on the binding energy and active site interactions accomplished with pharmacokinetic analysis. It was observed that both anisomycin and oleandomycin bind to all selected target proteins with good binding energy, achieving the most favorable interactions. Considering the results of binding affinity, pharmacokinetics and toxicity of anisomycin and oleandomycin, it is proposed that they can act as potential drugs against the SARS CoV-2 infection. Further clinical testing of the reported drugs is essential for their use in the treatment of SARS CoV-2 infection.

Multifunctional Derivatives of Spiropyrrolidine Tethered Indeno-Quinoxaline Heterocyclic Hybrids as Potent Antimicrobial, Antioxidant and Antidiabetic Agents: Design, Synthesis, In Vitro and In Silico Approaches.

To combat emerging antimicrobial-resistant microbes, there is an urgent need to develop new antimicrobials with better therapeutic profiles. For this, a series of 13 new spiropyrrolidine derivatives were designed, synthesized, characterized and evaluated for their in vitro antimicrobial, antioxidant and antidiabetic potential. Antimicrobial results revealed that the designed compounds displayed good activity against clinical isolated strains, with 5d being the most potent (MIC 3.95 mM against Staphylococcus aureus ATCC 25923) compared to tetracycline (MIC 576.01 mM). The antioxidant activity was assessed by trapping DPPH, ABTS and FRAP assays. The results suggest remarkable antioxidant potential of all synthesized compounds, particularly 5c, exhibiting the strongest activity with IC50 of 3.26 ± 0.32 mM (DPPH), 7.03 ± 0.07 mM (ABTS) and 3.69 ± 0.72 mM (FRAP). Tested for their α-amylase inhibitory effect, the examined analogues display a variable degree of α-amylase activity with IC50 ranging between 0.55 ± 0.38 mM and 2.19 ± 0.23 mM compared to acarbose (IC50 1.19 ± 0.02 mM), with the most active compounds being 5d, followed by 5c and 5j, affording IC50 of 0.55 ± 0.38 mM, 0.92 ± 0.10 mM, and 0.95 ± 0.14 mM, respectively. Preliminary structure-activity relationships revealed the importance of such substituents in enhancing the activity. Furthermore, the ADME screening test was applied to optimize the physicochemical properties and determine their drug-like characteristics. Binding interactions and stability between ligands and active residues of the investigated enzymes were confirmed through molecular docking and dynamic simulation study. These findings provided guidance for further developing leading new spiropyrrolidine scaffolds with improved dual antimicrobial and antidiabetic activities.

New substituted pyrazolones and dipyrazolotriazines as promising tyrosyl-tRNA synthetase and peroxiredoxin-5 inhibitors: Design, synthesis, molecular docking and structure-activity relationship (SAR) analysis.

New substituted pyrazolone and dipyrazolotriazine derivatives have been synthesized, designed and well characterized as promising dual antimicrobial/antioxidant agents to overcome multidrug resistant bacteria (MDR), oxidative stress and their related diseases. Among all strains, S. aureus was found to be the most susceptible for all compounds except 10b and 12b. Out of the three investigated series, sulfonamide analogues 5a-c displayed excellent antibacterial activity with 5b (MIC = 7.61 µM) and 5a (MIC = 8.98 µM) displaying activity that exceeds the reference drug tetracycline (MIC = 11.77 µM). The same sulfonamide derivatives 5a-c demonstrates high ABTS scavenging capacity comparable to standard. Moreover, the structure-activity relationship (SAR) revealed that benzenesulfonamide is a crucial group for enhancing activity. Molecular docking studies of the potent analogues were performed by targeting the crystal structures of S. aureus tyrosyl-tRNA synthetase and human peroxiredoxin-5 enzymes and the obtained results supported well the in vitro data revealing stronger binding interactions. Pharmacokinetics prediction together with modeling outcomes suggests that our sulfonamide derivatives may serve as useful lead compounds for the treatment of infectious disease.

Tomatidine and Patchouli Alcohol as Inhibitors of SARS-CoV-2 Enzymes (3CLpro, PLpro and NSP15) by Molecular Docking and Molecular Dynamics Simulations.

Considering the current dramatic and fatal situation due to the high spreading of SARS-CoV-2 infection, there is an urgent unmet medical need to identify novel and effective approaches for prevention and treatment of Coronavirus disease (COVID 19) by re-evaluating and repurposing of known drugs. For this, tomatidine and patchouli alcohol have been selected as potential drugs for combating the virus. The hit compounds were subsequently docked into the active site and molecular docking analyses revealed that both drugs can bind the active site of SARS-CoV-2 3CLpro, PLpro, NSP15, COX-2 and PLA2 targets with a number of important binding interactions. To further validate the interactions of promising compound tomatidine, Molecular dynamics study of 100 ns was carried out towards 3CLpro, NSP15 and COX-2. This indicated that the protein-ligand complex was stable throughout the simulation period, and minimal backbone fluctuations have ensued in the system. Post dynamic MM-GBSA analysis of molecular dynamics data showed promising mean binding free energy 47.4633 ± 9.28, 51.8064 ± 8.91 and 54.8918 ± 7.55 kcal/mol, respectively. Likewise, in silico ADMET studies of the selected ligands showed excellent pharmacokinetic properties with good absorption, bioavailability and devoid of toxicity. Therefore, patchouli alcohol and especially, tomatidine may provide prospect treatment options against SARS-CoV-2 infection by potentially inhibiting virus duplication though more research is guaranteed and secured.

Antimicrobial, Antioxidant, Anti-Acetylcholinesterase, Antidiabetic, and Pharmacokinetic Properties of Carum carvi L. and Coriandrum sativum L. Essential Oils Alone and in Combination.

Herbs and spices have been used since antiquity for their nutritional and health properties, as well as in traditional remedies for the prevention and treatment of many diseases. Therefore, this study aims to perform a chemical analysis of both essential oils (EOs) from the seeds of Carum carvi (C. carvi) and Coriandrum sativum (C. sativum) and evaluate their antioxidant, antimicrobial, anti-acetylcholinesterase, and antidiabetic activities alone and in combination. Results showed that the EOs mainly constitute monoterpenes with γ-terpinene (31.03%), ß-pinene (18.77%), p-cymene (17.16%), and carvone (12.20%) being the major components present in C. carvi EO and linalool (76.41%), γ-terpinene (5.35%), and α-pinene (4.44%) in C. sativum EO. In comparison to standards, statistical analysis revealed that C. carvi EO showed high and significantly different (p < 0.05) antioxidant activity than C. sativum EO, but lower than the mixture. Moreover, the mixture exhibited two-times greater ferric ion reducing antioxidant power (FRAP) (IC50 = 11.33 ± 1.53 mg/mL) and equipotent chelating power (IC50 = 31.33 ± 0.47 mg/mL) than the corresponding references, and also potent activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50 = 19.00 ± 1.00 mg/mL), ß-carotene (IC50 = 11.16 ± 0.84 mg/mL), and superoxide anion (IC50 = 10.33 ± 0.58 mg/mL) assays. Antimicrobial data revealed that single and mixture EOs were active against a panel of pathogenic microorganisms, and the mixture had the ability to kill more bacterial strains than each EO alone. Additionally, the anti-acetylcholinesterase and α-glucosidase inhibitory effect have been studied for the first time, highlighting the high inhibition effect of AChE by C. carvi (IC50 = 0.82 ± 0.05 mg/mL), and especially by C. sativum (IC50 = 0.68 ± 0.03 mg/mL), as well as the mixture (IC50 = 0.63 ± 0.02 mg/mL) compared to the reference drug, which are insignificantly different (p > 0.05). A high and equipotent antidiabetic activity was observed for the mixture (IC50 = 0.75 ± 0.15 mg/mL) when compared to the standard drug, acarbose, which is about nine times higher than each EO alone. Furthermore, pharmacokinetic analysis provides some useful insights into designing new drugs with favorable drug likeness and safety profiles based on a C. carvi and C. sativum EO mixture. In summary, the results of this study revealed that the combination of these EOs may be recommended for further food, therapeutic, and pharmaceutical applications, and can be utilized as medicine to inhibit several diseases.

Novel enantiopure isoxazolidine and C-alkyl imine oxide derivatives as potential hypoglycemic agents: Design, synthesis, dual inhibitors of α-amylase and α-glucosidase, ADMET and molecular docking study.

In an effort to explore a new class of antidiabetic inhibitors, a new series of isoxazolidine and C-alkyl imine oxide derivatives scaffolds were designed, synthesized and fully characterized. The newly synthesized analogues were evaluated for their human pancreatic α-amylase (HPA) and human lysosomal acid-α-glucosidase (HLAG) inhibitory activities and have shown a higher potency than acarbose. The compounds 7b (23.1 ± 1.1 µM) and 7a (36.3 ± 1.6 µM) were identified as the potent HPA and HLAG inhibitors with inhibitory effect up to 9 and 21-fold higher than acarbose, respectively. Antihyperglycemic activity results were supported by molecular docking approach of the most potent compounds 7b and 7a showing stronger interactions with the active site of HPA and HLAG as well as by in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) profile suggesting their satisfactory oral druglikeness without toxic effect. Therefore, it can be concluded that both 7b and 7a can be used as effective lead molecules for the development of HPA and HLAG inhibitors for the management of T2DM.

Multifunctional isoxazolidine derivatives as α-amylase and α-glucosidase inhibitors.

A series of novel isoxazolidines based on benzaldehyde derivatives have been synthesized from the cycloaddition of chiral menthone-based nitrone and allyl phenyl ethers. All synthetic compounds were assessed for their in vitro PPA, HPA and HLAG inhibitory activity. The results revealed that all targets exhibited better inhibitory effect against PPA (12.3 ± 0.4 < IC50 < 38.2 ± 0.9 µM), HPA (10.1 ± 0.4 < IC50 < 26.8 ± 0.2 µM) and HLAG (65.4 ± 1.2 < IC50 < 274.8 ± 1.1 µM) when compared with the reference inhibitor, acarbose (IC50 = 284.6 ± 0.3 µM for PPA, 296.6 ± 0.8 µM for HPA, 780.4 ± 0.3 µM for HLAG) with the highest PPA inhibitory activity was ascribed to compound 3g against both PPA and HPA, and 3b against HLAG enzymes, respectively. Structural activity relationships (SARs) were also established for all synthesized compounds and the interaction modes of the most potent inhibitors (3g for PPA and HPA, 3b for HLAG) and the active site with residues of three enzymes were confirmed through molecular docking studies. Furthermore, a combination of molecular docking analysis with the in vitro activities can help to improve prediction success and encourages the uses of some of these molecules as potential alternatives toward the modulation of T2D.

Design, synthesis ADMET and molecular docking of new imidazo[4,5-b]pyridine-5-thione derivatives as potential tyrosyl-tRNA synthetase inhibitors.

In our effort of discovering new antimicrobial agents, a novel series of imidazo[4,5-b]pyridine-5-thione scaffolds were designed and synthesized and their chemical structures were characterized by physicochemical and spectral analysis. The synthesized compounds were assessed for their in vitro antimicrobial activities against pathogenic microorganisms. Results revealed that out the tested compounds, 3 exhibited the potent inhibitory effect (MIC = 0.49 µg/mL) as compared to the positive control, chloramphenicol (0.98 µg/mL) which predicted also to have the best pharmacokinetic and druglikness properties as well as lower toxicity profiles. Preliminary structure-activity relationships (SARs) study has been also investigated. Moreover, to understand the binding patterns of the tested compounds in the Staphylococcus aureus tyrosyl-tRNA synthetase active site, molecular docking study using the most active compound 3 was carried out. The obtained results indicate that analog 3 can potentially bound to the target enzyme with the highest docking score (-9.37 kcal/mol). Overall, our results showed that antimicrobial activity as well as ADMET and toxicity predictions were in consensus with the docking results.

Synthesis and SPAR exploration of new semicarbazone-triazole hybrids in search of potent antioxidant, antibacterial and antifungal agents.

A new series of semicarbazone-triazole hybrid derivatives have been synthesized by condensation between heterocyclic aldehydes and the commercial semicarbazide hydrochloride. The in vitro antioxidant activity of these species was tested using 1,1-diphenyl-2-picrylhydrazyl radical, 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and Ferric reducing antioxidant power assays and their antimicrobial activity against different microbial strains was carried out. Furthermore, molecular properties prediction and drug likeness were also determinated using Molinspiration. Among such derivatives, compounds (E)-2-(4-((1-(2,6-dimethylphenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzylidene)hydrazine carboxamide (4c), and (E)-2-(4-((1-(2-methoxyphenyl)-1-H-1,2,3-triazol-4-yl)methoxy)benzylidene)hydrazine-carboxamide (4e) exhibit excellent scavenging ability, especially with IC50 = 1.57 ± 1.66 mg/mL (4c) and IC50 = 1.82 ± 0.15 mg/mL (4e) with 1,1-diphenyl-2-picrylhydrazyl radical and IC50 = 1.90 ± 1.33 mg/mL (4c) with 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) as compared to the standards butylhydroxytoluene (IC50 = 1.60 ± 1.98 mg/mL) and Trolox (IC50 = 1.45 ± 1.33 mg/mL), respectively. The antimicrobial assay results, show that compounds 4c and 4e highlighted the most interesting profile with the potent activity was obtained against S. enteritidis (1.56-fold) and then M. luteus (1.45-fold) which are significantly higher than the positive control, chloramphenicol. By the other hand, the synthesized semicarbazone derivatives met the Lipinski's rule criteria by presenting good drug likeness and bioactivity scores. The structure-property-activity relationships have been carried out in order to determine the effect of various substituents on the molecular and the biological properties. All these investigations confirm that our synthetic semicarbazone can be explored for generating new potential drug with good oral bioavailability.

Date Palm Trees Root-Derived Endophytes as Fungal Cell Factories for Diverse Bioactive Metabolites.

Endophytic fungi of healthy and brittle leaf diseased (BLD) date palm trees (Phoenix dactylifera L.) represent a promising source of bioactive compounds with biomedical, industrial, and pharmaceutical applications. The fungal endophytes Penicillium citrinum isolate TDPEF34, and Geotrichum candidum isolate TDPEF20 from healthy and BLD date palm trees, respectively, proved very effective in confrontation assays against three pathogenic bacteria, including two Gram-positive bacteria Bacillus thuringiensis (Bt) and Enterococcus faecalis (Ef), and one Gram-negative bacterium Salmonella enterica (St). They also inhibited the growth of three fungi Trichoderma sp. (Ti), Fusarium sporotrichioides (Fs), Trichoderma sp. (Ts). Additionally, their volatile organic compounds (VOCs) were shown to be in part responsible for the inhibition of Ti and Ts and could account for the full inhibition of Fs. Therefore, we have explored their potential as fungal cell factories for bioactive metabolites production. Four extracts of each endophyte were prepared using different solvent polarities, ethanol (EtOH), ethyl acetate (EtOAc), hexane (Hex), and methanol (MetOH). Both endophyte species showed varying degrees of inhibition of the bacterial and fungal pathogens according to the solvent used. These results suggest a good relationship between fungal bioactivities and their produced secondary metabolites. Targeting the discovery of potential anti-diabetic, anti-hemolysis, anti-inflammatory, anti-obesity, and cytotoxic activities, endophytic extracts showed promising results. The EtOAc extract of G. candidum displayed IC50 value comparable to the positive control diclofenac sodium in the anti-inflammatory assays. Antioxidant activity was evaluated using α,α-diphenyl-ß-picrylhydrazyl (DPPH), ß-carotene bleaching, reducing power (RP), and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonique) (ABTS) radical scavenging assays. The findings revealed strong anti-oxidant power with an IC50 of 177.55 µg/mL for G. candidum EtOAc extract using DPPH assay, probably due to high polyphenol and flavonoid content in both fungal extracts. Finally, LC-HRMS (Liquid Chromatography­High Resolution Mass Spectrometry) and GC-MS (Gas Chromatography­Mass Spectrometry) analysis of G. candidum and P. citrinum extracts revealed an impressive arsenal of compounds with previously reported biological activities, partly explaining the obtained results. Finally, LC-HRMS analysis indicated the presence of new fungal metabolites that have never been reported, which represent good candidates to follow for the discovery of new bioactive molecules.

Stereoselective synthesis of enantiopure N-substituted pyrrolidin-2,5-dione derivatives by 1,3-dipolar cycloaddition and assessment of their in vitro antioxidant and antibacterial activities.

1,3-Dipolar cycloaddition between a chiral nitrone and N-substituted maleimides afforded unprecedented enantiopure spiro-fused heterocycles in good yields with a high enantio- and diastereoselectivity. The reaction was taking place on the less hindered face of the nitrone. The obtaining heterocycles were screened for their in vitro antioxidant properties and the results revealed that the potent antioxidant activity was generally recorded to compounds (3g) and (3e). The in vitro antibacterial activities of these two compounds were also investigated and the results demonstrated the strongest potential of compound (3g) against all the tested bacteria. Molecular properties were analyzed and showed good oral drug candidate like properties and that could be exploited as a potential antioxidant and antimicrobial agent. Finally, the preliminary results obtained from this investigation attempted to clarify if the structurally different side chains of active compounds interfere with their biological properties.

Anti-microbial screening and cytotoxic activity of aerial part of Thymelaea hirsuta L. essential oil growing in south-west Tunisia.

This study aimed to investigate the antimicrobial and cytotoxic activities of essential oil isolated by the hydro-distillation of aerial parts of Thymelaea hirsuta. The antimicrobial activity of the oil was evaluated against eight bacterial and three fungal pathogenic strains. The results revealed that the essential oil exhibited a moderate-to-potent anti-microbial activity against all the microorganisms tested. Gram-positive bacteria were noted to be more sensitive to the oil than gram-negative bacteria and yeasts. In vitro cytotoxicity evaluation against HeLa cell lines showed that the essential oil exhibited moderate cytotoxicity on human tumor cells, with a high IC50 value of 175µg/mL. To the author's knowledge, this is the first study reporting on the antimicrobial and cytotoxic activities of Thymelaea hirsuta essential oil. Overall, the results indicate that the T. hirsuta essential oil has a number of attractive properties that might open new promising opportunities for the control or prevention of a wide range of microbial infections and cancers and can facilitate the use of essential oils as natural preservatives against spoilage microorganisms in food systems.

Chemical composition and in vitro evaluation of antioxidant, antimicrobial, cytotoxicity and anti-acetylcholinesterase properties of Tunisian Origanum majorana L. essential oil.

This study investigated the chemical composition and evaluated the antioxidant, antimicrobial, cytotoxic and anti-acetylcholinesterase properties of Tunisian Origanum majorana essential oil. The findings showed that the oil exhibited high activity, particularly in terms of reducing power and ß-Carotene bleaching, inducing higher IC50 values than BHT. The oil showed an important antimicrobial activity against 25 bacterial and fungal strains. In fact, the IZ, MIC and MBC values recorded for the bacterial strains were in the range of 8 ± 0-18.33 ± 0.57 mm, 0.097-3.125 and 0.39-6.25 mg/mL, respectively. The IZ, MIC and MFC values of the fungal strains varied between 11±0-28 ± 0 mm, 0.058-0.468 mg/mL and 0.234-1.875 mg/mL, respectively. A low cytotoxic effect was observed against cancer (Hep-2 and HT29) and continuous cell lineage (Vero), with CC50 values ranging from 13.73 to 85.63 mg/mL. The oil was also evaluated for anti-acetylcholinesterase effects, which showed that it exhibited significant activity with IC50 values reaching 150.33 ± 2.02 µg/mL.

Crystallization, solubility and thermodynamics of the highly thermostable glucose isomerase from Streptomyces sp. strain.

The crystallization behaviour of the highly thermostable glucose isomerase from the Streptomyces sp. strain isolated from Tunisian soil was investigated using ammonium sulfate as a precipitating agent. We established phase diagrams at different temperatures and protein concentrations. It was found that the solubility increased with increasing temperature and decreased with increasing salt concentration. The temperature-dependent solubility was used to characterize the thermodynamic parameters of crystallization such as enthalpy, entropy and free energy.

RETRACTED: Alminderej et al. Antimicrobial and Wound Healing Potential of a New Chemotype from Piper cubeba L. Essential Oil and In Silico Study on S. aureus tyrosyl-tRNA Synthetase Protein. Plants 2021, 10, 205.

The journal retracts the article, 'Antimicrobial and Wound Healing Potential of a New Chemotype from Piper cubeba L. Essential Oil and In Silico Study on S. aureus tyrosyl-tRNA Synthetase Protein' [...].

Identification of dual-target isoxazolidine-isatin hybrids with antidiabetic potential: Design, synthesis, in vitro and multiscale molecular modeling approaches.

In the development of novel antidiabetic agents, a novel series of isoxazolidine-isatin hybrids were designed, synthesized, and evaluated as dual α-amylase and α-glucosidase inhibitors. The precise structures of the synthesized scaffolds were characterized using different spectroscopic techniques and elemental analysis. The obtained results were compared to those of the reference drug, acarbose (IC50 = 296.6 ± 0.825 µM for α-amylase & IC50 = 780.4 ± 0.346 µM for α-glucosidase). Among the title compounds, 5d exhibited impressive α-amylase and α-glucosidase inhibitory activity with IC50 values of 30.39 ± 1.52 µM and 65.1 ± 3.11 µM, respectively, followed by 5h (IC50 = 46.65 ± 2.3 µM; IC50 = 85.16 ± 4.25 µM) and 5f (IC50 = 55.71 ± 2.78 µM; IC50 = 106.77 ± 5.31 µM). Mechanistic studies revealed that the most potent derivative 5d bearing the chloro substituent attached to the oxoindolin-3-ylidene core, and acarbose, are a competitive inhibitors of α-amylase and α-glucosidase, respectively. Structure activity relationship (SAR) was examined to guide further structural optimization of the most appropriate substituent(s). Moreover, drug-likeness qualities and ADMET prediction of the most active analogue, 5d was also performed. Subsequently, 5d was subjected to molecular docking and dynamic simulation during the progression of 120 ns analysis to check the essential ligand-receptor patterns, and to estimate its stability. In silico studies were found in good agreement with the in vitro enzymatic inhibitions results. In conclusion, we demonstrated that most potent compound 5d could be exploited as dual potential inhibitor of α-amylase and α-glucosidase for possible management of diabetes.