MIC Values Research Articles

Synthesis, antibacterial, anti-urease, DFT and molecular docking studies of novel bis-1,3,4-thiadiazoles

A series of 2-substitutedamino-1,3,4-thiadiazoles (4a-4j) were synthesized starting from various isothiocyanate derivatives. The newly synthesized compounds were characterized by 1H NMR, 13C NMR, and elemental analysis. All compounds were tested for antibacterial activity against Proteus vulgaris (ATCC 7829) via the microbroth dilution technique. Among them, compound 4h emerged as the most potent antibacterial agent with MIC value of 4.1 μM. All synthetic compounds were additionally evaluated for their urease inhibitory activity and exhibited good inhibitory potential against urease with IC50 values in the range of 1.732 ± 0.186 - 3.786 ± 0.300 μM as compared to the standard thiourea (IC50 = 11.008 ± 0.932 μM). Compounds 4d, 4h and 4i showed significant inhibitory effects with IC50 values of 1.981 ± 0.265, 1.732 ± 0.186 and 1.937 ± 0.173 μM, respectively. In silico molecular docking study showed the critical interactions of compound 4h with the active site of the urease. According to DFT, compounds 4j and 4d (with low ΔE=4.536 eV and 4.629 eV values, respectively) are more chemically reactive than the other molecules, in which consistent with their inhibitory potentials against the urease enzyme. Molecular Dynamics simulations also were performed to assess the energetic features of the urease in complex with compound 4h. Furthermore, the predicted ADMET characteristics of the compound 4h was calculated using QikProp to gain insights into its pharmacokinetic properties. These newly identified inhibitors of the urease enzyme can serve as leads for further antibacterial drug research and development.

Effect of the Phenological Stage on the Phenolic Composition, and Antioxidant and Antimicrobial Properties of Cirsium vulgare (Savi) Ten. Extracts.

Cirsium vulgare (Savi) Ten. is a plant from the Asteraceae family that is commonly used in traditional medicine. The purpose of this work was to investigate the antioxidant and antimicrobial characteristics of phenolic compounds found in ethanol and dry extracts of C. vulgare leaves, inflorescence, and roots during various phenological stages. Apigenin-7-O-glucoside and chlorogenic acid were identified in practically all C. vulgare extracts. Extracts from leaves collected at the end of the phenological dormancy period and in the first growing year had the highest antioxidant (cupric ion-reducing antioxidant capacity of 12,938 Trolox equivalents/g dry weight) and antimicrobial activity (against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Proteus vulgaris, and Candida albicans) with MIC values of ethanol extract from 16.7 mg/mL to 8.35 mg/mL. These extracts included a high concentration of chlorogenic acid and apigenin-7-O-glucoside. Also, dry extracts from C. vulgare roots and inflorescences showed a higher antimicrobial effect compared to ethanolic extracts with MIC values from 5.57 mg/mL to 3 mg/mL. The study emphasizes the critical role of phenological stages and raw material composition in the accumulation of phenolic compounds and their biological activity in C. vulgare. The findings suggest that extracts from C. vulgare leaves, especially those collected at the end of the phonological dormancy period, are promising candidates for further research into bioactive compounds with potential medicinal applications. The strong antioxidant and antibacterial properties of these extracts highlight their potential for development into natural pharmaceutical products.

Inhibition of Oral Pathogenic Bacteria, Suppression of Bacterial Adhesion and Invasion on Human Squamous Carcinoma Cell Line (HSC-4 Cells), and Antioxidant Activity of Plant Extracts from Acanthaceae Family.

Medicinal plants have traditionally been used to treat various human diseases worldwide. In this study, we evaluated the leaf extracts of plants from the Acanthaceae family, specifically Clinacanthus nutans (Burm.f.) Lindau, Thunbergia laurifolia Lindl., and Acanthus ebracteatus Vahl., for their compounds and antioxidant activity. The ethanolic extracts of A. ebracteatus showed the highest total phenolic content at 22.55 mg GAE/g extract and the strongest antioxidant activities, with IC50 values of 0.24 mg/mL and 3.05 mg/mL, as determined by DPPH and ABTS assays. The antibacterial efficacy of these extracts was also tested against Streptococcus pyogenes, Streptococcus mutans, Staphylococcus aureus, and Klebsiella pneumoniae. The diameters of the inhibition zones ranged from 14.7 to 17.3 mm using the agar well diffusion method, with MIC and MBC values ranging from 7.81 to 250 mg/mL. Anti-biofilm formation, antibacterial adhesion, and antibacterial invasion assays further demonstrated that these medicinal plant extracts can inhibit bacterial biofilm formation and prevent the adhesion and invasion of oral pathogenic bacteria on the human tongue squamous cell carcinoma-derived cell line (HSC-4 cells). The ethanolic extracts of C. nutans and A. ebracteatus were able to inhibit the gtfD and gbp genes, which facilitate biofilm formation and bacterial adherence to surfaces. These findings provide new insights into the antibacterial and antioxidant properties of plant extracts from the Acanthaceae family. These activities could enhance the clinical and pharmaceutical applications of plant extracts as an alternative therapy for bacterial infections and a dietary supplement.

Synthesis and evaluation of the anti-TB activity of novel 7-(2-(4-substituted-phenyl)-4,5-diphenyl-1H-imidazol-1-yl)-4-methyl-2H-chromen-2-one derivatives and their DFT studies for NLO application

A series of novel 7-(2-(4-substituted-phenyl)-4,5-diphenyl-1H-imidazol-1-yl)-4-methyl-2H-chromen-2-one derivatives 5(a-g) have been synthesized and reported as anti-TB activity and non-linear optical applications. The activity results show that compounds 5b, 5c, 5d, 5f, and 5g exhibited excellent efficacy with a MIC value of 3.12 μg/mL, one-fold greater than the reference standard streptomycin (6.26 μg/mL). An in silico molecular docking study was performed against InhA protein and the results were consistent with the experimental results. Computational studies were performed using the DFT method and results reveal that the presence of greater electronegativity atoms increases the HOMO-LUMO energy gap. The NLO properties show that the presence of stronger electron-donating substituents increases the ICT, charge delocalization and β0 values. The NBO analysis shows significant interactions between LP (Lone pair), π* and σ* in compounds account for the high polarization and enhanced NLO activity.

Understanding chromoblastomycosis in Sri Lanka; insights into fungal aetiology and antifungal susceptibility patterns

Introduction: Chromoblastomycosis is a chronic disfiguring fungal infection of the subcutaneous tissue found mainly in the socio-economically marginalized population in the tropical and sub-tropical regions, characterized by the presence of sclerotic cells. This study was done with the aim of identifying the antifungal sensitivity patterns of the causative agents of chromoblastomycosis in Sri Lanka from 1992 to 2019.Methodology: Study was done on the stored isolates received from patients with chromoblastomycosis since 1992 to 2019, to the Mycology Reference Laboratory of Medical Research Institute, Colombo. Isolates were revived by subculture on Potato dextrose agar. Identification was done phenotypically. Antifungal sensitivity testing was performed by E test method. Available demographic and clinical data were analysed.Results: Of the 74 isolates, 71 (96%) were caused by Fonsecaea pedrosoi. Mean MIC for the antifungals tested were lowest for posaconazole 0.015 μg/ml followed by itraconazole 0.225 μg/ml, and voriconazole 0.768 μg/ml while amphotericin B demonstrated complete resistance with mean MIC of 30.591 μg/ml. No statistically significant differences were noted on the antifungal sensitivity of the isolates from 1992 to 2004 and 2005 to 2019.Conclusions: Fonsecaea pedrosoi was the commonest causative agent causing chromoblastomycosis in the studied population. Posaconazole demonstrated the lowest MIC values for the tested isolates followed by itraconazole and voriconazole. Amphotericin B demonstrated very high MIC values which were likely to result in clinical failure upon treatment. MIC values demonstrated minimal fluctuations throughout the tested time.

Exploration of newly synthesized transition metal(II) complexes for infectious diseases.

Aim: In the annals of human history, infectious diseases significantly influencing the collective well-being of people worldwide. Consequently, to identify effective agents for infectious ailments, the octahedral Co(II), Ni(II), Cu(II), Zn(II) complexes of 4-(3-methoxyphenyl)pyrimidin-2-amine and 2-methoxy-1-napthaldehyde based ligand were synthesized and well characterized in the current investigation.Results & methodology: The synthesized compounds were evaluated for anti-TB, anti-inflammatory, antibacterial, antifungal activities by microplate Alamar blue, bovine serum albumin, serial dilution assays. The [Zn(L1)2(H2O)2] complex (5) demonstrates robust potency with 0.0040±0.0007 and 0.0038μmol/ml MIC value in anti-tuberculosis and antimicrobial activities, correspondingly while 06.57±0.03μM IC50 value in anti-inflammatory investigation.Conclusion: Complex (5) show promising potential as targets for pathogen deformities, supported by rigorous biological and computational investigations including pharmacophore modelling, molecular docking (binding score -121.018 and -59.8662kcal/mol for 6H53 and 1CX2 proteins, respectively), DFT (Density functional theory), MESP (MolecularElectrostaticPotential) and ADMET (absorption, distribution, metabolism, excretion and toxicity).

Antifungal, Antioxidant, and Irritative Potential of Citronella Oil (Cymbopogon nardus) Associated with Phenethyl Ester of Caffeic Acid (CAPE)

The present study aimed to analyze the antifungal, antioxidant, and irritant potential of citronella oil, both isolated and combined with caffeic acid phenethyl ester (CAPE), for topical oral candidiasis. The antioxidant potential was evaluated using two methods, the DPPH test and the reducing power test (FRAP), while the irritant potential of the solutions was assessed through the hen’s egg chorioallantoic membrane test (HET-CAM). The DPPH test (IC50) values for the CITRO III + CAPE III combination were 32 ± 9 mg/mL, and for isolated CAPE, 13 ± 3 mg/mL. The results from the FRAP method revealed a low iron-reducing power for the combination of 1.25 mg/mL of citronella and 0.0775 mg/mL of CAPE (CITRO III + CAPE III), showing no significant difference compared to the isolated solution of 0.15 mg/mL of CAPE. The antibacterial activity of CAPE and isolated citronella in vitro against microorganisms was evaluated using two methods: microdilution and biofilm assay. The results showed that the MIC and MFC values were 0.5 mg/mL for citronella at both tested times (24 h and 48 h). For CAPE, the MFC values were 0.031 mg/mL. For the biofilm assay, the isolated compounds and combinations at 1 min and 6 h showed significantly different results from the controls (p < 0.05). Furthermore, the HET-CAM results demonstrated the absence of irritability. Based on these premises, the antifungal and antioxidant actions, and absence of irritability were proven. Moreover, this work presents a natural antifungal of interest to the pharmaceutical industry.

Pyrrolidine, Piperazine, and Diazinane Alkaloids from the Marine Bacterium Strain Vibrio ruber ZXR-93.

Four new alkaloids, vibripyrrolidine A (1), vibripiperazine A (2), and vibridiazinane A, B (3, 4), comprising one pyrrolidine, one piperazine, and two diazinane alkaloids, along with two known analogs (5, 6), were isolated from the marine bacterium Vibrio ruber ZXR-93 cultured in ISP2 medium. Their chemical structures were elucidated by analysis of their 1D and 2D NMR, mass spectra, and electronic circular dichroism (ECD) calculations. Compounds 1 and 3-6 showed vigorous antibacterial activity against Staphylococcus aureus, with MIC values ranging from 0.96 to 7.81 μg/mL. Moreover, compound 1 exhibited robust anti-inflammatory activity in vitro using the LPS-induced RAW264.7 macrophage model. All compounds also showed moderate antineoplastic activity against cervical cancer cells (HeLa) and gastric cancer cells (SGC-7901).

Novel antifungal talaroenamine L with unusual leptosphaeronyl moiety from marine-derived Talaromyces sp. HDN17-428 via HDACi elicitation

Vorinostat elicitation of the deep-sea fungus Talaromyces sp. HDN17-428 resulted in the isolation of one new compound, talaroenamine L (1) with unusual leptosphaeronyl moiety and three known compounds (2–4). Structures of 1–4 were confirmed by extensive NMR, HRESIMS and OR calculations. Antimicrobial activities of all compounds were tested in which compounds 1–4 showed substantial antifungal activities with MIC values ranged from 3.1 to 12.5 μM.

Design and synthesis of spiro[pyrrolidine-3,3′-quinoline]-2,2′-dione derivatives as novel antifungal agents targeting chitin synthase

A novel spiro [pyrrolidine-3′,3′-quinoline]-2,2′-dione scaffold was constructed using fragments of quinoline and pyrrolidine. Subsequently, two series of derivatives were designed based on this scaffold. The enzyme inhibition experiments revealed that all designed compounds had moderate to good inhibitory activity against chitin synthase (CHS). The inhibitory effects of compounds 5i, 5j, 8i and 8n were approximately equal to that of control drug polyoxin B (PB, IP = 86.4 ± 2.9 %, IC50 = 0.082 ± 0.013 mM) which is a well-established CHS inhibitor. The results from enzyme kinetic parameters assays proved that these compounds act as non-competitive inhibitors of CHS. The sorbitol protection experiments demonstrated the tested compounds disrupted the synthesis of cell wall, which further verified that the target of these compounds is CHS. The experiments of antimicrobial showed that compounds 5b, 5f, 5i, 5j, 8f, 8i, 8m, 8n and 8o had strong antifungal activity against the four tested pathogenic fungi strains frequently emerging in clinical setting, with MIC values ranging from 4 to 32 μg/mL, which were either superior to or comparable with those of PB or fluconazole. Furthermore, these compounds displayed synergistic or additive effects when combined with fluconazole and these active compounds also showed promising activity against fluconazole-resistant and micafungin-resistant fungi variants. The result of antimicrobial experiments indicated that these compounds had minimal activity to tested bacterial strains. This suggests that they had selective antifungal activity. The results of ADME prediction, in conjunction with the cytotoxicity assay results, indicated that these compounds had favorable pharmacokinetic profiles and low toxicity. In addition, molecular docking studies illustrated that the compound had a strong affinity with the CHS, which was consistent with the results of enzymatic assays. These findings indicated that the designed compounds are non-competitive inhibitors of CHS with good selectivity and broad-spectrum antifungal activity, and possess significant antifungal activity against drug-resistant fungi, suggesting their potential as lead compounds for the development of novel drugs against drug-resistant fungi.

Synthesis, antimicrobial activity, molecular docking and MD simulation studies, in silico ADME investigations and thermo-acoustic studies of heterocyclic dihydropyrimidine substituted 1,3,4-thiadiazole scaffolds

The connections between the chemical structures and antibacterial properties of different functional groups including organic molecules were examined in this study. we have synthesized a novel series of 1,3,4-thiadiazole hybrids (5a-o) based on 3,4-dihydropyrimidines. After an effective synthesis, the compounds' structure was confirmed by using spectrum techniques like IR, 1H NMR, 13C NMR, and mass spectrometry. Elemental analyses were performed on a Perkin-Elmer 2400 CHN analyzer and the resulting data were within the accepted range (± 0.40) of the calculated values. The in vitro antimicrobial activity of the compounds against a range of bacterial and fungal species. Compound 5i showed potent inhibitory effects against P. aeruginosa with MIC values of 12.5 μg/ml S. aureus and A.niger were positively affected by compound 5k with MIC values of 12.5 μg/ml and 50 μg/ml, respectively. Based on the results, compounds 5a and 5o have moderate activity against C.albicans and E. coli with MIC values of 50 μg/ml and 62.5 μg/ml respectively. Furthermore, molecular docking and molecular dynamics simulations were used to identify the most stable conformation of newly discovered inhibitors. Thermo-acoustical properties of derivatives 5k and 5l in DMSO and DMF solvent have been determined at three different atmospheric pressure temperatures (298.15, 308.15, and 318.15)K. The components of the liquid mixture's molecular interactions have been taken into account to explain these results. The acquired results are interpreted in terms of interactions between solutes and solvents, providing insight into the compounds' potential to form or disrupt structures in DMSO and DMF solutions.

Impact of transferable β-lactamases and intrinsic AmpC amino acid substitutions on the activity of cefiderocol against wild-type and iron uptake-deficient mutants of Pseudomonas aeruginosa.

We aimed to analyse the interplay between impaired iron uptake and β-lactamases on cefiderocol resistance in Pseudomonas aeruginosa. Thirty-one transferable β-lactamases and 16 intrinsic P. aeruginosa AmpC (PDC) variants were cloned and expressed in wild-type (PAO1) and iron uptake-deficient (PAO ΔpiuC) P. aeruginosa backgrounds. MICs of cefiderocol and antipseudomonal β-lactams were determined by reference broth microdilution. Relative to PAO1, deletion of piuC caused a specific 16-fold decrease in cefiderocol activity but negligible effects on the activity of other β-lactams. Among transferable β-lactamases, SHV-12, KPC Ω-loop mutants, NDMs and OXA-15 showed cefiderocol MIC values above the clinical breakpoint (2 mg/L) when expressed in PAO1. When expressed in PAO ΔpiuC, these and the transformants harbouring PER-1, VEB-1, KPC-2, KPC-3, VIM-1, CMY-2, OXA-2 and OXA-14 showed increased MIC values from 16 to >256 mg/L. The PDC variants carrying the Ω-loop changes ΔP215-G222 (PDC-577), E219K (PDC-221 and PDC-558) and the H10 helix change L293P (PDC-219) had the greatest impact on cefiderocol resistance, with MICs of 2-4 mg/L in PAO1 and of up to 32-64 mg/L in PAO ΔpiuC. Widespread enzymes such as GES, CTX-M-9, CTX-M-15, VIM-2-like enzymes, IMPs, DHA-1, FOX-4, OXA-10, OXA-48 and the other PDC variants tested had weaker effects on cefiderocol resistance. We add evidence about the effect of the interplay between iron uptake and β-lactamases on the acquisition of cefiderocol resistance in P. aeruginosa. These findings may help to anticipate the emergence of resistance and optimize the use of cefiderocol against P. aeruginosa infections.

Effect of Age on the Pharmacokinetics of Marbofloxacin Following Intravenous Administration in Calves.

The aim of this study was to compare the pharmacokinetics of marbofloxacin after intravenous (IV) administration of a single dose of 10 mg/kg to calves of different ages. The study was carried on 1- (n = 6), 2- (n = 6), and 4-month-old (n = 6) Montofon calves. Plasma concentrations of marbofloxacin were measured using HPLC, and pharmacokinetic data were calculated by non-compartmental analysis. The elimination half-life (t1/2ʎz), volume of distribution at steady state (Vdss), total clearance (ClT), and area under the concentration-versus time curve (AUC0-∞) values of marbofloxacin in 1-month-old calves were 10.62 h, 1.03 L/kg, 0.08 L/h/kg, and 127.90 h*μg/mL, respectively. While the t1/2ʎz (from 10.62 to 3.36 h) and AUC0-∞ (from 127.90 to 47.35 h*μg/mL) decreased in parallel with the age of the calves, ClT (from 0.08 to 0.21 L/h/kg) increased. The Vdss of marbofloxacin was higher in 1- and 2-month-old calves compared to 4-month-old calves. After IV administration of marbofloxacin at a dose of 10 mg/kg, an ƒAUC0-24/MIC90 ratio of ≥ 125 was obtained for bacteria with MIC90 values of ≤ 0.60, ≤ 0.39 and ≤ 0.27 μg/mL in 1-, 2-, and 4-month-old calves, respectively. These results show that the antibacterial effect of marbofloxacin, which has concentration-dependent activity, decreases due to age-related pharmacokinetic changes and that the 10 mg/kg dose should be reviewed according to the MIC90 value of the bacteria.

Antibacterial activity of secondary metabolites from the roots of Solanum dasyphyllum: A combined in vitro and in silico study

Solanum dasyphyllum is widely utilized for folk medicine in Ethiopia. The chromatographic separation of root extract of S. dasyphyllum led to the isolation of six compounds: tremulacin (1), scopoletin (2), stigmasterol (3), β-sitosterol (4), palmitic acid (5) and 2,3-dihydroxypropyl-9Z,12Z-octadecadienoate (6). The structures of the compounds were determined using NMR (1D and 2D), MS and comparison with literature data. The extract and isolated compounds were in vitro assayed against six bacterial strains and displaying activity against the tested strains. The extract exhibited stronger activity against E. coli, K. pneumoniae, and P. aeruginosa, with MIC values of 0.195±0.0, 0.391±0.0, and 0.195±0.0 mg/mL, respectively. The isolated compounds also showed good antibacterial activity with the highest activity was recorded for compound 2, with MIC values of 0.313±0.0 mg/mL against K. pneumoniae, while for the ciprofloxacin is 0.195±0.0 mg/mL against the same strain. In silico molecular docking analyses were performed for compounds 1, 2 and 3 against E. coli DNA gyrase B, P. aeruginosa LasR protein, and K. pneumoniae using AutoDock Vina and showed better binding activity. The in vitro antibacterial results and in silico analysis of the compounds revealed the potential of these compounds to be lead compound for antibacterial drug discovery. KEY WORDS: Solanum dasyphyllum, Chromatographic separation, Antibacterial activity, Molecular docking Bull. Chem. Soc. Ethiop. 2024, 38(6), 1843-1860. DOI: https://dx.doi.org/10.4314/bcse.v38i6.26

Tephrosin and obovatachalcone with antibacterial activity from Tephrosia vogelii Hook.f

In the search for new antibacterial agents from plants, two known compounds (rotenoid and chalcone) were isolated from Tephrosia vogelii Hook.f. (seeds), namely tephrosin (1), and obovatachalcone (2). The compounds were isolated using vacuum liquid chromatography and radial chromatography. The structures of isolates were determined by 1D and 2D NMR. Both compounds were evaluated for their antibacterial properties against the four pathogenic bacterial strains Staphylococcus aureus S33 R4, Bacillus subtilis subsp. subtilis str. 168, Escherichia coli TISTR 780, and Salmonella typhi Ty 21a, using the microdilution method to determine MIC and MBC. The results showed that tephrosin (1) had moderate antibacterial activity against E. coli with MIC values of 25 μg/mL and MBC values of 100 μg/mL. However, obovatachalcone (2) showed a weak antibacterial activity.

Green synthesis of copper oxide nanoparticles using Ficus racemosa leaf extract and investigation of its antibacterial properties

ABSTRACT The present work reports a one-pot green synthesis of copper oxide nanoparticles (CuO NPs) using Ficus racemosa leaf extract via a green chemistry approach without using any harsh chemical reagents. The crystalline and single-phase CuO NPs were analysed via XRD. DLS revealed the average particle size distribution, and zeta potential was used for the evaluation of surface charge. Optical properties were determined at 530 nm through UV–Vis spectroscopy with a broad peak in the range from 500 to 590 nm. Different functional groups in the leaf extract containing flavonoids and polyphenols as reducing agents responsible for the synthesis of CuO NPs were verified through FTIR. The FESEM images revealed the average particle size in the range from 30 to 300 nm with a spherical morphology, and EDS was used for the quantitative elemental analysis. The strong bacterial inhibition tendency of CuO NPs against 12 bacterial strains including Bacillus cereus, Campylobacter jejuni, Bacillus subtilis, Clostridium perfringens, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Shigella dysenteriae, Listeria monocytogenes, Helicobacter pylori, and Salmonella typhi was observed with MIC values between 60 and 1000 µg/mL. The findings suggest that the synthesis of CuO NPs via green chemistry can serve as a potential substitute for traditional multi-step chemical synthetic routes.

HPLC-PDA Analysis of Polyacetylene Glucosides from Launaea capitata and Their Antibacterial and Antibiofilm Properties against Klebsiella pneumoniae.

Background/Objectives: Bacterial resistance and virulence are challenges in treating bacterial infections, especially in Klebsiella pneumoniae. Plants of the Launaea Cass. genus are used traditionally to address a variety of diseases, including infections, but the potential bioactive compounds are unknown. Our goals were to verify the potential contribution of two major polyacetylene glycosides isolated from our previous study, (3S,6E,12E)-6,12-tetradecadiene-8,10-diyne-1-ol 3-O-β-D-glucopyranoside (1) and bidensyneoside A (syn. gymnasterkoreaside A) [(3R,8E)-3-hydroxy-8-decene-4,6-diyn-1-yl β-D-glucopyranoside] (2), to the anti-infective properties of Launaea capitata and to develop a dependable HPLC method for their quantification; Methods: On a panel of K. pneumoniae clinical isolates, the antibacterial action of 1, 2, and the methanol extract of the whole L. capitata plant were evaluated by broth microdilution assay, while their antibiofilm action was evaluated by the crystal violet assay. qRT-PCR investigated luxS, mrkA, wzm, and wbbm genes that encode biofilm formation and quorum sensing (QS). The antibacterial activity of 1 was revealed by employing mice infection. Chromatographic separation was conducted using isocratic elution on a Hypersil BDS C18 column using a photodiode array (PDA) detector; Results: Compound 1 showed antibacterial activity with MIC values of 16-128 µg/mL. It remarkably reduced strong and moderate biofilm-forming bacterial isolates from 84.21% to 42.1% compared with the extract (68.42%) and 2 (78.95%). Compound 1 also downregulated the QS genes, luxS, mrkA, wzm, and wbbm, and exhibited in vivo antibacterial action through the enhancement of the histological construction of the liver and spleen, decreased TNF-α immunoreaction, bacterial burden, and the inflammatory mediators IL-1β and IL-6. A successful HPLC-PDA approach was developed to separate the binary mixture of 1 and 2 in less than 10 min with high sensitivity, with detection limits down to 0.518 and 0.095 µg/mL for 1 and 2, respectively; Conclusions: Compound 1 exhibited remarkable antibacterial and antibiofilm properties and may contribute to the anti-infectious traditional uses of L. capitata, meriting further clinical studies and serving as a reliable quality control biomarker for the plant.

Biological and Computational Studies of Hydrazone Based Transition Metal(II) Complexes.

In the chronicles of human history, infectious diseases played a pivotal role, influencing societies, steering advancements in medicine, and significantly impacting the well-being of people worldwide. Consequently, in the pursuit of identifying effective combating agents for infectious ailments, the Co(II), Ni(II), Cu(II), Zn(II) complexes of N'-(4-nitrobenzylidene)benzohydrazide were synthesized in the current investigation. Numerous spectral and physical analysis were conducted to characterize the compounds which revealed octahedral stereochemistry of complexes. The anti-tuberculosis, anti-inflammatory, antibacterial and antifungal investigations demonstrated that the compounds (1-5) have significant efficacy for these infectious ailments. The [Zn(L)2(H2O)2] complex (5) has comparable TB inhibition potency to streptomycin as shown by MIC value of 0.0196±0.0003 μmol/mL. Additionally, the anti-inflammatory, antibacterial and antifungal studies also revealed the comparable inhibiting property of (5) to standard drugs with significant IC50 (07.49±0.08 μM) and MIC (0.0098 μmol/mL) values. Furthermore, pharmacophore modeling with addition of molecular docking, DFT, MESP, ADMET were employed against compounds (1-5) to give a new insight in biological evaluations. The pharmacophore modeling suggested that (5) has a distinctive pharmacophoric features including cationic sites, hydrogen-bond donors and acceptors which provide valuable insights into rational drug design for specific pharmacological applications. Moreover, another in silico investigations authenticate the bioactivity of (5) through substantial binding affinities, binding energy, stability, hardness, electrophilicity etc. Overall, the combined computational and experimental results highlight the potential of [Zn(L)2(H2O)2] as a promising candidate for tuberculosis treatment, meriting further in vivo investigations.

Design, synthesis, biological evaluation study of spirocyclic POM analogues as novel MmpL3 anti-tubercular agent

We present the development of a phenyl oxazole methyl (POM) core structure with spirocyclic derivatives as part of our efforts to discover innovative anti-tuberculosis agents. Derivatives of spirocyclic POM were synthesized and evaluated for their inhibitory effects on M.tuberculosis (M. tb) H37Rv. Notably, compound 5c displayed potent anti-tubercular activity with MIC value of 0.206 μM in culture broth medium. Furthermore MIC values of compound 5c against DS/MDR/pre-XDR clinical isolates ranged from 0.34 to 0.68 μg/mL, 0.17 to 0.68 μg/mL, and 0.17 to 0.34 μg/mL, respectively. Also, compound 5c with favorable ADME and PK properties was not cytotoxic to THP-1 human cells. Based on the spontaneous mutant generation, we have identified the target of compound 5c to be MmpL3. The computational docking study suggested its plausible binding mode against MmpL3. There is no approved drug targeting this target yet, and the outcomes of the presented research will contribute to the future discovery of novel anti-tuberculosis drugs.

Tityus stigmurus-Venom-Loaded Cross-Linked Chitosan Nanoparticles Improve Antimicrobial Activity.

The rapid resistance developed by pathogenic microorganisms against the current antimicrobial pool represents a serious global public health problem, leading to the search for new antibiotic agents. The scorpion Tityus stigmurus, an abundant species in Northeastern Brazil, presents a rich arsenal of bioactive molecules in its venom, with high potential for biotechnological applications. However, venom cytotoxicity constitutes a barrier to the therapeutic application of its different components. The objective of this study was to produce T. stigmurus-venom-loaded cross-linked chitosan nanoparticles (Tsv/CN) at concentrations of 0.5% and 1.0% to improve their biological antimicrobial activity. Polymeric nanoparticles were formed with a homogeneous particle size and spherical shape. Experimental formulation parameters were verified in relation to mean size (<180 nm), zeta potential, polydispersity index and encapsulation efficiency (>78%). Tsv/CN 1.0% demonstrated an ability to increase the antimicrobial venom effect against Staphylococcus aureus bacteria, exhibiting an MIC value of 44.6 μg/mL. It also inhibited different yeast species of the Candida genus, and Tsv/CN 0.5% and 1.0% led to a greater inhibitory effect of C. tropicalis and C. parapsilosis strains, presenting MIC values between 22.2 and 5.5 µg/mL, respectively. These data demonstrate the biotechnological potential of these nanosystems to obtain a new therapeutic agent with potential antimicrobial activity.