Design, synthesis, In-vitro, In-silico and DFT studies of novel functionalized isoxazoles as antibacterial and antioxidant agents.

A series of new isoxazolederivatives incorporating the sulfonate ester function has been synthesized from 2-benzylidenebenzofuran-3(2 H)-one, known as aurone. The synthesis of the target compounds was carried out following an efficient methodology that allows access to the desired products in a reproducible way and with good yield. The structures of the synthesized compounds were established using NMR (1H and 13C) spectroscopy and mass spectrometry. A theoretical study was performed to optimize the geometrical structures and to calculate the structural and electronic parameters of the synthesized compounds. The calculations were also carried out to understand the influence and the effect of substitutions on the chemical reactivity of the studied compounds. The synthesized isoxazoles were screened for their antioxidant and antibacterial activities. The findings demonstrate that the studied compounds exhibit good to moderate antibacterial activity against the tested bacteria (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli). Moreover, a number of the tested isoxazole derivatives exhibit high effectiveness against DPPH free radicals. Besides that, molecular docking studies were carried out to predict binding affinity and identify the most likely binding interactions between the active molecules and the target microorganisms' proteins. A 100 ns molecular dynamics study was then conducted to examine the dynamic behavior and stability of the highly potent isoxazole 4e in complex with the target bacterial proteins. Finally, the ADMET analyses suggest that all the synthesized isoxazoles have good pharmacokinetic profiles and non-toxicity and non-carcinogenicity in biological systems.

In Vitro and In Silico Studies of Antimicrobial, and Antioxidant Activities of Chemically Characterized Essential Oil of Artemisia flahaultii L. (Asteraceae).

The present study investigated the antioxidant and antimicrobial activities as well as characterized the chemical composition of the essential oils (EO) isolated from Artemisia flahaultii (EOF). EOF was extracted using hydro-distillation, and the chemical composition of EOF was ascertained by gas chromatography coupled with mass spectrometry (GC/MS). To assess antioxidant capacity, three tests were used: the 2,2-diphenyl-1-picrylhydrazil (DPPH), the total antioxidant capacity (TAC) and the ferric-reducing antioxidant power (FRAP) test. The antimicrobial activity of EOF was investigated using the diffusion assay and minimal inhibitory concentration assays (MICs). By use of in silico structure-activity simulations, the inhibitory potency against nicotinamide adenine dinucleotide phosphate (NADPH), physicochemical characters, pharmaco-centric properties and absorption, distribution, metabolism, excretion (ADME) characteristics of EOF were determined. GC/MS analysis reveals 25 components majorly composed of D-Limonene (22.09%) followed by ß-pinene (15.22%), O-cymene (11.72%), ß-vinylnaphthalene (10.47%) and benzene 2,4-pentadiynyl (9.04%). The capacity of DPPH scavenging by EOF scored an IC50 of 16.00 ± 0.20 µg/mL. TAC revealed that the examined oils contained considerable amounts of antioxidants, which were determined to be 1094.190 ± 31.515 mg ascorbic acid equivalents (AAE)/g EO. Results of the FRAP method showed that EOF exhibited activity with EC50 = 6.20 ± 0.60 µg/mL. Values for minimal inhibitory concentration (MIC) against certain clinically important pathogenic bacteria demonstrate EOF's potent antibacterial activity. MIC values of 1.34, 1.79, and 4.47 µg/mL against E. coli, B. subtilis and S. aureus were observed respectively. EOF exhibited significant antifungal activities against two stains of fungi: F. oxysporum and C. albicans, with values of 10.70 and 2.23 µg/mL, respectively. Of the total, 25 essential oils were identified. 2,4-Di-tert-butylphenol and capillin were the most active molecules against NADPH. The ADME prediction revealed that EOF was characterized by useful physicochemical characteristics and pharmaco-centric properties. The findings of this study show that the EOF can be used as an alternative to treat microbial resistance. Based on the in silico studies, EOF can be used as an "eco-friendly" NADPH inhibitor.

Antimicrobial and Antioxidant Properties of Chemically Analyzed Essential Oil of Artemisia annua L. (Asteraceae) Native to Mediterranean Area.

Artemisia annua (AA) is an aromatic plant belonging to the Asteraceae family, which has long been known for its several medicinal virtues. In addition, essential oils (EOs) extracted from AA have a wide range of therapeutic properties. Therefore, this study aimed to investigate the phytochemical composition, anti-microbial, and anti-oxidant properties of Artemisia annua essential oil (EOAA). EO was extracted, and its chemical constituents were ascertained by the use of GC-MS analysis. EOAA shows remarkable antioxidant capacities of DPPH free radical scavenging with an IC50 value of 29 ± 5.3 µg/mL and ferric reducing antioxidant power with an EC50 value of 9.21 ± 0.3 µg/mL, and it also has a good total antioxidant capacity of 911.59 ± 115.71 milligrams of ascorbic acid equivalence per gram of EO (mg AAE/g EO). Moreover, the in vitro antimicrobial screening results indicate that EOAA has shown promising antibacterial activity, especially against the Escherichia coli strain, and it also shows significant antifungal activity against Fusarium oxysporum and Candida albicans yeasts. Taken together, our findings highlight the importance of EOAA as a source of strong antioxidant and antimicrobial agents, which could be used as an alternative form to control free radicals and combat drug-resistant microbes.

Synthesis, Characterization, DFT Mechanistic Study, Antimicrobial Activity, Molecular Modeling, and ADMET Properties of Novel Pyrazole-isoxazoline Hybrids.

A series of new heterocycle hybrids incorporating pyrazole and isoxazoline rings was successfully synthesized, characterized, and evaluated for their antimicrobial responses. The synthesized compounds were obtained utilizing N-alkylation and 1,3-dipolar cycloaddition reactions, as well as their structures were established through spectroscopic methods and confirmed by mass spectrometry. To get more light on the regioselective synthesis of new hybrid compounds, mechanistic studies were performed using DFT calculations with B3LYP/6-31G(d,p) basis set. Additionally, the results of the preliminary screening indicate that some of the examined hybrids showed potent antimicrobial activity, compared to standard drugs. The results confirm that the antimicrobial activity is strongly dependent on the nature of the substituents linked pyrazole and isoxazoline rings. Furthermore, molecular docking studies were conducted to highlight the interaction modes between the investigated hybrid compounds and the Escherichia coli and Candida albicans receptors. Notably, the results demonstrate that the investigated compounds have strong protein binding affinities. The stability of the formed complexes by the binding between the hybrid compound 6c, and the target proteins was also confirmed using a 100 ns molecular dynamics simulation. Finally, the prediction of ADMET properties suggests that almost all hybrid compounds possess good pharmacokinetic profiles and no signs of observed toxicity, except for compounds 6e, 6f, and 6g.

GC-MS Profiling, In Vitro Antioxidant, Antimicrobial, and In Silico NADPH Oxidase Inhibition Studies of Essential Oil of Juniperus thurifera Bark.

Juniperus thurifera is a native species to the mountains of the western Mediterranean region. It is used in traditional medicine as a natural treatment against infections. The present study aimed to carry out the chemical analysis and evaluate the antioxidant, antimicrobial, as well as in silico inhibition studies of the essential oils from Juniperus thurifera bark (EOEJT). Chemical characterization of EOEJT was done by gas chromatography (GC-MS). We have performed three antioxidant assays (Reducing power (FRAP), 2, 2-diphenylpicrylhydrazyl (DPPH), and total antioxidant capacity (TAC)) of the EOEJT. We next evaluated the antimicrobial activity against in silico study, which was carried out to help evaluate the inhibitory effect of EOEJT against NADPH oxidase. Results of the GC/MS analysis revealed seven major compounds in EOEJT wherein muurolol (36%) and elemol (26%) were the major components. Moreover, EOEJT possessed interesting antioxidant potential with an IC50 respectively of 21.25 ± 1.02 µg/mL, 481.02 ± 5.25 µg/mL, and 271 µg EAA/mg in DPPH, FRAP, and total antioxidant capacity systems. Molecular docking of EOEJT in NADPH oxidase active site showed inhibitory activity of α-cadinol and muurolol with a glide score of -6.041 and -5.956 Kcal/mol, respectively. As regards the antibacterial and antifungal capacities, EOEJT was active against all tested bacteria and all fungi, notably, against Escherichia coli K12 with an inhibition diameter of 21 mm and a MIC value of 0.67 mg/mL, as well as against Proteus mirabilis ATCC 29906 with an inhibition diameter of 18.33 ± 1.15 mm and a MIC value of 1.34 mg/mL. A more pronounced effect was recorded for the fungal pathogens Fusarium oxysporum MTCC 9913 with inhibition of 37.44 ± 0.28% and MIC value of 6.45 mg/mL, as well as against Candida albicans ATCC 10231 with an inhibition diameter of 20.33 ± 1.15 mm and a MIC value of 0.67 ± 0.00 mg/mL. Altogether, these results highlight the importance of EOEJT as a source of natural antibacterial and antioxidant drugs to fight clinically important pathogenic strains.

Antioxidant and Antimicrobial Activities of Chemically-Characterized Essential Oil from Artemisia aragonensis Lam. against Drug-Resistant Microbes.

This study investigated the chemical composition, antioxidant and antimicrobial activity of essential oil extracted from Artemisia aragonensis Lam. (EOA). Hydrodistillation was employed to extract EOA. Gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry analyses (GC-MS) were used to determine the phytochemical composition of EOA. Antioxidant potential was examined in vitro by use of three tests: 2.2-diphenyl-1-picrilhidrazil (DPPH), ferric reducing activity power (FRAP) and total antioxidant capacity assay (TAC). Agar diffusion and microdilution bioassays were used to assess antimicrobial activity. GC/MS and GC-FID detected 34 constituents in the studied EOA. The major component was Camphor (24.97%) followed by Borneol (13.20%), 1,8 Cineol (10.88%), and Artemisia alcohol (10.20%). EOA exhibited significant antioxidant activity as measured by DPPH and FRAP assays, with IC50 and EC50 values of 0.034 ± 0.004 and 0.118 ± 0.008 mg/mL, respectively. EOA exhibited total antioxidant capacity of 7.299 ± 1.774 mg EAA/g. EOA exhibited potent antibacterial activity as judged by the low minimum inhibitory concentration (MIC) values against selected clinically-important pathogenic bacteria. MIC values of 6.568 ± 1.033, 5.971 ± 1.033, 7.164 ± 0.0 and 5.375 ± 0.0 µg/mL were observed against S. aureus, B. subtills, E. coli 97 and E. coli 57, respectively. EOA displayed significant antifungal activity against four strains of fungi: F. oxysporum, C. albicans, A. flavus and A. niger with values of 21.50 ± 0.43, 5.31 ± 0.10, 21.50 ± 0.46 and 5.30 ± 0.036 µg/mL, respectively. The results of the current study highlight the importance of EOA as an alternative source of natural antioxidant and antibacterial drugs to combat antibiotic-resistant microbes and free radicals implicated in the inflammatory responses accompanying microbial infection.

Insecticidal and Antifungal Activities of Chemically-Characterized Essential Oils from the Leaves of Withania frutescens L.

The current study was conducted to investigate antifungal and insecticidal activities of essential oil extracted from the Moroccan Withania frutescens L. (EOW), and their chemical composition was profiled. To achieve this goal, EOW was extracted by the hydro-distillation method and their phytochemical constituents were characterized by gas chromatography-mass spectrometry analyses (GC-MS). Insecticidal activity was evaluated by use of four tests: contact toxicity, inhalation toxicity, and repellent tests. Antifungal activity was evaluated on Fusarium oxysporum f. sp. Ciceris (F. oxysporum) using different concentrations of EOW. GC/MS analysis revealed that EOW was rich in carvacrol (31.87%), thymol (30.08%), and camphor (9.13%). At a 1-µL/L dose, EOW exhibited mortality rates of 23.13 ± 1.07% and 24.41 ± 1.21% against Callosobruchus maculatus (C.maculatus) by inhalation and contact, respectively. Notably, EOW dose of 20 µL/L caused significant mortality rates of 95.1 ± 3.5% and 76.69 ± 1.71% by inhalation and contact, respectively. EOW exhibited an inhibitory effect on mycelial growth against the tested fungi F. oxysporum of 100% and 93.5 ± 1.1% for the 9 and 4.5 mg/mL doses, respectively. The reduced mycelial growth rate for F. oxysporum was recorded to be 0.3 ± 0.1 and 0.6 ± 0.1 mm/h for the EOW doses of 2.25 and 4.5 mg/mL, respectively. The outcome of the present work showed that EOW has a promising antifungal and insecticidal activity, and it can therefore be employed as a natural alternative insecticidal and mycocidal agent to replace the chemically-synthesized ones.

Chemical Analysis and Antioxidant and Antimicrobial Activity of Essential oils from Artemisia negrei L. against Drug-Resistant Microbes.

BACKGROUND: Artemisia negrei L. (A. negrei) is a medicinal and aromatic plant belonging to the family Asteraceae that is more widespread in the folded Middle Atlas Mountains, Morocco. MATERIALS AND METHODS: This study was run to investigate the phytochemical composition and antioxidant, antibacterial, and antifungal activities of Artemisia negrei L. essential oil. This oil was extracted from the fresh plant material by using the Clevenger apparatus. The phytochemical composition was characterized by GC-MS. The antioxidant activity was evaluated using different methods including DPPH, ß-carotene bleaching, and total antioxidant capacity. The antibacterial activity was tested vs. multidrug-resistant bacteria including both Gram-negative and Gram-positive using inhibition zones in agar media and minimum inhibitory concentration (MIC) bioassays. The antifungal activity was conducted on Candida albicans, Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum using a solid medium assay. RESULTS: The chromatographic characterization of essential oils of A. negrei revealed the presence of 34 compounds constituting 99.91% of the total essential oil. The latter was found to have promising antioxidant activity by all bioassays used such as DPPH, ß-carotene bleaching, and total antioxidant capacity. The results obtained showed that our plant oils had potent antibacterial activity towards Gram-negative (E. coli 57, E. coli 97, K. pneumonia, and P. aeruginosa) and Gram-positive (S. aureus), so that the maximum inhibition zones and MIC values were around 18-37 mm and 3.25 to 12.5 mg/mL, respectively. The oil also showed antifungal activity towards Candida albicans, Fusarium oxysporum, and Aspergillus Niger except for flavus species. CONCLUSION: The findings obtained in the work showed that A. negrei can serve as a valuable source of natural compounds that can be used as a new weapon to fight radical damage and resistant microbes.