Synthesis, Antioxidant, Molecular Docking and DNA Interaction Studies of Metal-Based Imine Derivatives.

Currently, numerous ongoing studies are investigating the interaction of free radicals with biological systems, such as lipids, DNA and protein. In the present work, synthesis, characterization, antioxidant, DNA binding and molecular docking studies of Schiff base ligand and its Ni(II), Co(II), Cu(II) and Zn(II) were evaluated. The metal complexes have shown significant dose-dependent antioxidant activities higher than those of the free ligand but lesser than those of the standard antioxidant, ascorbic acid. The DNA binding constants (Kb) were found in the order Zn(pimp)2 {9.118 × 105 M-1} > H-pimp {3.487 × 105 M-1} > Co(pimp)2 {3.090 × 105 M-1} > Ni(pimp)2 {1.858 × 105 M-1} > Cu(pimp)2 {1.367 × 105 M-1}. Binding constants (Kb) values calculated from the molecular docking analysis were found to be in close agreement with the experimental results. The obtained results indicate the importance of synthesis complexes as a source of synthetic antioxidants and anticancer drugs.

Synthesis, molecular structure and urease inhibitory activity of novel bis-Schiff bases of benzyl phenyl ketone: A combined theoretical and experimental approach.

Background: Urease belongs to the family of amid hydrolases with two nickel atoms in their core structure. On the basis of literature survey, this research work is mainly focused on the study of bis-Schiff base derivatives of benzyl phenyl ketone nucleus. Objective: Synthesis of benzyl phenyl ketone based bis-Schiff bases in search of potent urease inhibitors. Method: In the current work, bis-Schiff bases were synthesized through two steps reaction by reacting benzyl phenyl ketone with excess of hydrazine hydrate in ethanol solvent in the first step to get the desired hydrazone. In last, different substituted aromatic aldehydes were refluxed in catalytic amount of acetic acid with the desired hydrazone to obtain bis-Schiff base derivatives in tremendous yields. Using various spectroscopic techniques including FTIR, HR-ESI-MS, and 1H NMR spectroscopy were used to clarify the structures of the created bis-Schiff base derivatives. Results: The prepared compounds were finally screened for their in-vitro urease inhibition activity. All the synthesized derivatives (3-9) showed excellent to less inhibitory activity when compared with standard thiourea (IC50 = 21.15 ± 0.32 µM). Compounds 3 (IC50 = 22.21 ± 0.42 µM), 4 (IC50 = 26.11 ± 0.22 µM) and 6 (IC50 = 28.11 ± 0.22 µM) were found the most active urease inhibitors near to standard thiourea among the synthesized series. Similarly, compound 5 having IC50 value of 34.32 ± 0.65 µM showed significant inhibitory activity against urease enzyme. Furthermore, three compounds 7, 8, and 9 exhibited less activity with IC50 values of 45.91 ± 0.14, 47.91 ± 0.14, and 48.33 ± 0.72 µM respectively. DFT used to calculate frontier molecular orbitals including; HOMO and LUMO to indicate the charge transfer from molecule to biological transfer, and MEP map to indicate the chemically reactive zone suitable for drug action. The electron localization function (ELF), non-bonding orbitals, AIM charges are also calculated. The docking study contributed to the analysis of urease protein binding.

Exploring the synthesis, structure, spectroscopy and biological activities of novel 4-benzylidene-1-(2-(2,4-dichloro phenyl)acetyl) thiosemicarbazide derivatives: An integrated experimental and theoretical investigation.

Background: Novel α-amylase inhibitors play a crucial role in managing diabetes and obesity, contributing to improved public health by addressing these challenging and prevalent conditions. Moreover, the synthesis of anti-oxidant agents is essential due to their potential in combating oxidative stress-related diseases and promoting overall health. Objective: Synthesis of thoisemicarbazone derivatives of 2,4-dichlorophenyl acetic acid and to screened them for their biological activities. Method: Thiosemicarbazone derivatives (4-13) were synthesized by refluxing 2,4-dichlorophenyl acetic acid with sulfuric acid in ethanol to get the ester (2), which was further refluxed with thiosemicarbazide to get compound (3). Finally, different aromatic aldehydes were refluxed with compound (3) in ethanol in catalytic amount of acetic acid to obtained the final products (4-13). Using modern spectroscopic techniques including HR-ESI-MS, 13C-, and 1H NMR, the structures of the created derivatives were confirmed. Results: The synthesized derivatives showed excellent to good inhibitory activity in the range of IC50 values of 4.95 ± 0.44 to 69.71 ± 0.05 µM against α-amylase enzyme when compared to standard drug acarbose (IC50 = 21.55 ± 1.31 µM). In case of iron chelating activity, these products showed potent activity better than standard EDTA (IC50 = 66.43 ± 1.07 µM) in the range of IC50 values of 22.43 ± 2.09 to 61.21 ± 2.83 µM. However, the obtained products also show excellent to good activity in the range of IC50 values of 28.30 ± 1.17 to 64.66 ± 2.43 µM against hydroxyl radical scavenging activity when compared with standard vitamin C (IC50 = 60.51 ± 1.02 µM). DFT used to calculate different reactivity factors including ionization potential, electronegativity, electron affinity, chemical softness, and chemical hardness were calculated using frontier molecular orbital (FMO) computations. The molecular docking studies for the synthesized derivatives with α-amylase were carried out using the AutoDock Vina to understand the binding affinities with active sites of the protein.

Genotoxicity and cytotoxicity potential of organoselenium compounds in human leukocytes in vitro.

In the current work, cytotoxicity and genotoxicity of different organoselenium compounds were examined using Trypan blue exclusion and alkaline comet assays with silver staining respectively. Leukocytes were subjected to a 3-hour incubation with organoselenium compounds at concentrations of 1, 5, 10, 25, 50, and 75 µM, or with the control vehicle (DMSO), at a temperature of 37 °C. The viability of the cells was evaluated using the Trypan blue exclusion method, while DNA damage was analyzed through the alkaline comet assay with silver staining. The exposure of leukocytes to different organoselenium compounds including i.e. (Z)-N-(pyridin-2-ylmethylene)-1-(2-((2-(1-((E)-pyridin-2-ylmethyleneamino)ethyl)phenyl)diselanyl)phenyl)ethanamine (C1), 2,2'(1Z,1'E)-(1,1'-(2,2'-diselanediylbis(2,1-phenylene))bis(ethane-1,1-diyl)) bis(azan-1-yl-1-ylidene)bis -methan-1-yl-1-ylidene)diphenol (C2), and dinaphthyl diselenide (NapSe)2, At concentrations ranging from 1 to 5 µM, no significant DNA damage was observed, as indicated by the absence of a noteworthy increase in the Damage Index (DI). Our results suggest that the organoselenium selenium compounds tested were not genotoxic and cytotoxic to human leukocytes in vitro at lower concentration. This study offers further insights into the genotoxicity profile of these organochalcogens in human leukocytes. Their genotoxicity and cytotoxicity effects at higher concentration are probably mediated through reactive oxygen species generation and their ability to catalyze thiol oxidation.

Molecular docking and in vitro antibacterial activity of chiral phthalimide on ESBL producing gram negative bacteria.

Antibiotic resistance is tricky enemy that challenges our healthcare system. It is a stealthy, adaptive and ever evolving opponent, which can take years to develop but can spread like wildfire. In this study, derivatives of chiral phthalimides were developed with this aim to control the growth of resistant strains of Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa by targeting their resistance causing proteins and explore their binding interaction focal points through computational docking. Total 8 novel chiral phthalimides were synthesized and its antibiogram analysis was done on Muller-Hinton Agar by disc diffusion method. Cytotoxicity studies were made to check efficacy of tested compounds on human RBCs and monitor release of hemoglobin absorbance at 540nm. By using in silico molecular approach, crystal structure of target protein was retrieved from Protein Data Bank and docked through Autodock vina and PyRx. The obtained results revealed that seven out of eight compounds have active inhibitory effects against virulent strains. Minimum Inhibitory Concentration (MIC) was measured for most potent compounds i.e., 2-(1,3-dioxoisoindolin-2-yl)-3-(4-hydroxyphenyl) propanoic acid (compound 7) and 3-(1,3-dioxoisoindolin-2-yl) propanoic acid (compound 8). Docking studies displayed a report of highest affinity binding points i.e., amino acids LYS315, ALA318, TYR150, THR262, HIS314 and ARG148 for compound 7 while ALA 318, LYS 315, ARG14 and ILE291 for compound 8.

Design, Synthesis, Crystal Structure, In Vitro and In Silico Evaluation of New N'-Benzylidene-4-tert-butylbenzohydrazide Derivatives as Potent Urease Inhibitors.

BACKGROUND: Hydrazides play a vital role in making biologically active compounds in various fields of chemistry. These determine antioxidant, antidepressant, antimalarial, anti-inflammatory, antiglycating, and antimicrobial activity. In the present study, twenty-three new N' benzylidene-4-(tert-butyl)benzohydrazide derivatives (4-26) were synthesized by the condensation of aromatic aldehydes and commercially available 4-(tert-butyl)benzoic acid. All the target compounds were successfully synthesized from good to excellent yield; all synthesized derivatives were characterized via spectroscopic techniques such as HREI-MS and 1H-NMR. Synthesized compounds were evaluated for in vitro urease inhibition. All synthesized derivatives demonstrated good inhibitory activities in the range of IC50 = 13.33 ± 0.58-251.74 ± 6.82 µM as compared with standard thiourea having IC50 = 21.14 ± 0.425 µM. Two compounds, 6 and 25, were found to be more active than standard. SAR revealed that electron donating groups in phenyl ring have more influence on enzyme inhibition. However, to gain insight into the participation of different substituents in synthesized derivatives on the binding interactions with urease enzyme, in silico (computer simulation) molecular modeling analysis was carried out.

Thiolated PVP-Amphotericin B Complexes: An Innovative Approach toward Highly Mucoadhesive Gels for Mucosal Leishmaniasis Treatment.

The aim of this study was to synthesize polymeric excipients that can form mucoadhesive hydrogels containing amphotericin B (AmB) for the treatment of mucosal leishmaniasis. 2-(2-Acryloylaminoethyldisulfanyl)-nicotinic acid (ACENA) was copolymerized with N-vinyl pyrrolidone to obtain thiolated polyvinylpyrrolidone (PVP) that was then complexed with AmB to improve its solubility. The resulting structure of thiolated PVP was evaluated by 1H nuclear magnetic resonance to confirm S-protected thiol groups, and the average molecular mass was determined by size exclusion chromatography. Moreover, variants of thiolated PVP-AmB were studied for the thiol content, amount of complexed AmB, cytotoxicity, mucoadhesive properties, and antileishmaniasis activity. The highest achieved degree of thiolation was 772 ± 24.64 µmol/g, and the amount of complexed AmB was 27.05 ± 0.31 µmol per g of polymer. Thiolated PVP and thiolated PVP-AmB variants (0.5% m/v) showed no cytotoxicity, whereas the equivalent concentration of free AmB reduced Caco-2 cell viability to 70% within 24 h. Thiol-functionalized PVP and PVP-AmB complexes displayed 7.66- and 7.20-fold higher adhesion to the mucosal surface in comparison to unmodified PVP and PVP-AmB, respectively. In addition, variants of thiolated PVP-AmB complexes displayed 100% antileishmaniasis activity in comparison to the 80% killing efficiency of Fungizone, which has been applied in the equivalent AmB concentration of 0.2 µg/mL. Thiol-functionalized PVP proved to be a promising novel excipient for the delivery of AmB providing enhanced solubility and improved mucoadhesive properties which are beneficial for the treatment of mucosal leishmaniasis.

Curcumin-loaded self-emulsifying drug delivery system (cu-SEDDS): a promising approach for the control of primary pathogen and secondary bacterial infections in cutaneous leishmaniasis.

Cutaneous leishmaniasis being a neglected tropical disease (NTD) faces several challenges in chemotherapy. If infected with secondary bacterial infections, the treatment regime of cutaneous ulcers in cutaneous leishmaniasis is further complicated which usually require two or more than two chemotherapeutic agents for healing. In the current study, seven curcumin-loaded self-emulsifying drug delivery system (cu-SEDDS) formulations (namely F1-F7) were prepared by mixing different excipients (oils, surfactants, and co-solvents) through stirring (vortex) and sonication. The formulations were characterized regarding their droplet size, polydispersity index (PDI), and zeta potential by zeta sizer. The cu-SEDDS formulations displayed different sizes ranging from 32.4 up to 80.0 nm. The zeta potential of the formulations ranged from - 1.56 up to - 4.8. The antileishmanial activities of the cu-SEDDS formulations in terms of IC50 against Leishmania tropica ranged from 0.19 up to 0.37 µg/ml. The minimum inhibitory concentrations (MICs) of these formulations against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae were in the range of 48-62 µg/ml. The hemolysis caused by formulations was 1-2%. The spreading potential of the formulations (F1 and F5) over damaged skin model was remarkable. These results suggest that cu-SEDDS further enhanced the broad spectrum antileishmanial and antibacterial profile of curcumin and could be used for the treatment of cutaneous leishmaniasis and its associated secondary infections.

Synthesis, biological activities, and molecular docking studies of 2-mercaptobenzimidazole based derivatives.

A new series of N-acylhydrazone derivatives of 2-mercaptobenzimidazole (2-MBI) has been synthesized through S-alkylation with 1-bromotetradecane and N-alkylation with ethyl-2-chloroacetate. The resulting ester was synthetically modified through hydrazine hydrate to acyl hydrazide which was condensed with aromatic aldehydes to afford the title N-acylhydrazones (4-17). Chemical structures of the newly synthesized compounds have been confirmed through mass, FT-IR and 1HNMR techniques. In vitro free radical scavenging and α-glucosidase inhibition activities of the compounds were investigated with reference to the standard ascorbic acid and acarbose, respectively. Amongst the target compounds, 13 showed the highest inhibition in DPPH scavenging assay (IC50 = 131.50 µM) and α-glucosidase inhibition potential (IC50 = 352 µg/ml). We extended our investigations to explore the mechanism of enzyme inhibition and conducted docking analysis by using Molecular Operating Environment (MOE 2016.08). A homology model for α-glucosidase was constructed and validated using Ramachandran plot. Docking studies were also carried out on human intestinal α-glucosidases. In view of the importance of the nucleus involved, the synthesized compounds might find extensive medicinal applications as reported in the literature.

Flurbiprofen derivatives as novel α-amylase inhibitors: Biology-oriented drug synthesis (BIODS), in vitro, and in silico evaluation.

Novel derivatives of flurbiprofen 1-18 including flurbiprofen hydrazide 1, substituted aroyl hydrazides 2-9, 2-mercapto oxadiazole derivative 10, phenacyl substituted 2-mercapto oxadiazole derivatives 11-15, and benzyl substituted 2-mercapto oxadiazole derivatives 16-18 were synthesized and characterized by EI-MS, 1H and 13C NMR spectroscopic techniques. All derivatives 1-18 were screened for α-amylase inhibitory activity and demonstrated a varying degree of potential ranging from IC50 = 1.04 ±â€¯0.3 to 2.41 ±â€¯0.09 µM as compared to the standard acarbose (IC50 = 0.9 ±â€¯0.04 µM). Out of eighteen compounds, derivatives 2 (IC50 = 1.69 ±â€¯0.1 µM), 3 (IC50 = 1.04 ±â€¯0.3 µM), 9 (IC50 = 1.25 ±â€¯1.05 µM), and 13 (IC50 = 1.6 ±â€¯0.18 µM) found to be excellent inhibitors while rest of the compounds demonstrated comparable inhibition potential. A limited structure-activity relationship (SAR) was established by looking at the varying structural features of the library. In addition to that, in silico study was conducted to understand the binding interactions of the compounds (ligands) with the active site of α-amylase enzyme.

Xanthine oxidase inhibitory activity of nicotino/isonicotinohydrazides: A systematic approach from in vitro, in silico to in vivo studies.

Change in life style and eating habits has led to an increased prevalence of hyperuricemia worldwide. The role of hyperuricemia is no more restricted to gout, but it has a central role in progression of CVD, hypertension, metabolic syndrome, and arthritis. Among the different factors involved in regulation of serum uric acid, xanthine oxidase (XO) is the best pharmacological target to control the levels of serum uric acid as it catalyzes the final steps in uric acid production. In the current study, a systemic search for the inhibitors of xanthine oxidase, starting from synthesis to in vitro screening and leading to in vivo studies is presented. Benzylidene nicotino/isonicotinohydrazides (1-54) were synthesized by treating nicotinic/isonicotinic hydrazides with substituted aromatic aldehyde, and characterized by EI-MS and 1H NMR. Elemental analysis was also performed. All synthetic compounds were screened for xanthine oxidase inhibitory activity initially using an in vitro spectroscopic XO inhibition assay. Among them twenty-two derivatives were found to be active with IC50 values between 0.96 and 330.4µM, as compared to standard drug allopurinol IC50=2.00±0.01µM. Kinetic studies of five most active compounds (8, 35, 36, 39, and 45) with low IC50 values between 0.96 and 54.8µM showed a competitive mode of inhibition. Further in silico molecular docking was carried out to study the interactions of these inhibitors with catalytically important amino acid residues in XO. Three compounds 8, 35, and 36 with IC50 values of 10, 12.4, and 0.96µM, respectively, were also found to be non-cytotoxic, and thus selected for in vivo studies. A simple and physiologically relevant animal model was used to analyze the in vivo XO inhibitory activity of these compounds. Among these, two compounds 35, and 36 showed a significant inhibition in male Wistar rats, and identified as potential lead molecules for anti-hyperuricemic drug development.

Increase in serum alkaline phosphatase due to fatty meal in undergraduate students of Khyber Medical University, Khyber Pakhtunkhwa.

OBJECTIVE: To evaluate the effect of fatty meal on intestinal alkaline phosphatase. METHODS: The cross-sectional study was conducted at Khyber Medical University, Peshawar, Pakistan from March to April 2014 and comprised young healthy individuals 18-25 years of age. Whole blood samples were collected from the subjects in ethylenediaminetetraacetic acid anti-coagulated and plane serum tubes. For blood group analysis, blood group anti sera were used, while for serum alkaline phosphatase, a chemistry analyser was used. Alkaline phosphatase levels in the blood before and after breakfast were compared. RESULTS: Of the 177 subjects, there were 139(78.5%) men and 38(21.4%) women. Mean fasting alkaline phosphatise level was 144.22+/-75.57, while mean random value was 174.15+/-96.70 (p=0.001). CONCLUSIONS: Serum alkaline phosphatise must be analysed in fasting state early in the morning.

Evaluation of bisindole as potent ß-glucuronidase inhibitors: synthesis and in silico based studies.

Bisindole analogs 1-17 were synthesized and evaluated for their in vitro ß-glucuronidase inhibitory potential. Out of seventeen compounds, the analog 1 (IC50=1.62±0.04 µM), 6 (IC50=1.86±0.05 µM), 10 (IC50=2.80±0.29 µM), 9 (IC50=3.10±0.28 µM), 14 (IC50=4.30±0.08 µM), 2 (IC50=18.40±0.09 µM), 19 (IC50=19.90±1.05 µM), 4 (IC50=20.90±0.62 µM), 7 (IC50=21.50±0.77 µM), and 3 (IC50=22.30±0.02 µM) showed superior ß-glucuronidase inhibitory activity than the standard (d-saccharic acid 1,4-lactone, IC50=48.40±1.25 µM). In addition, molecular docking studies were performed to investigate the binding interactions of bisindole derivatives with the enzyme. This study has identified a new class of potent ß-glucouronidase inhibitors.

Discovery of novel oxindole derivatives as potent α-glucosidase inhibitors.

A series of 6-chloro-3-oxindole derivatives 1-25 were synthesized in high yields by the reaction of 6-chlorooxindole with different aromatic aldehydes in the presence of piperidine. All the synthesized compounds were isolated with E configuration. The structures were confirmed using spectroscopic techniques, including (1)H NMR and EIMS. These compounds showed varying degree of yeast α-glucosidase inhibition and seven were found as potent inhibitors of the enzyme. Compounds 2, 3, 4, 5, 6, 23, and 25 exhibited IC50 values 2.71±0.007, 11.41±0.005, 37.93±0.002, 15.19±0.004, 24.71±0.007, 17.33±0.001, and 14.2±0.002µM, respectively, as compared to standard acarbose (IC50, 38.25±0.12µM). Docking studies helped to find interactions between the enzyme and the active compounds. As a result of this study, oxindoles have been discovered as a new class of α-glucosidase inhibitors which have not been reported earlier.

Synthesis and structure-activity relationship of thiobarbituric acid derivatives as potent inhibitors of urease.

A series of thiobarbituric acid derivatives 1-27 were synthesized and evaluated for their urease inhibitory potential. Exciting results were obtained from the screening of these compounds 1-27. Compounds 5, 7, 8, 11, 16, 17, 22, 23 and 24 showed excellent urease inhibition with IC50 values 18.1 ± 0.52, 16.0 ± 0.45, 16.0 ± 0.22, 14.3 ± 0.27, 6.7 ± 0.27, 10.6 ± 0.17, 19.2 ± 0.29, 18.2 ± 0.76 and 1.61 ± 0.18 µM, respectively, much better than the standard urease inhibitor thiourea (IC50=21 ± 0.11 µM). Compound 3, 4, 10, and 26 exhibited comparable activities to the standard with IC50 values 21.4 ± 1.04 and 21.5 ± 0.61 µM, 22.8 ± 0.32, 25.2 ± 0.63, respectively. However the remaining compounds also showed prominent inhibitory potential The structure-activity relationship was established for these compounds. This study identified a novel class of urease inhibitors. The structures of all compounds were confirmed through spectroscopic techniques such as EI-MS and (1)H NMR.

Punicalagin improves inflammation and oxidative stress in rat model of pelvic inflammatory disease.

Pelvic inflammatory disease (PID) is one of the major public health concerns accounting for 30% of infertility and 50% of ectopic pregnancy cases due to severe inflammation and fibrosis. Punicalagin® are known to exhibit potent anti-inflammatory activity. The aim of this study was to demonstrate the anti-inflammatory and antioxidant effects of Punicalagin®, against pelvic inflammatory disease in rats. Female Sprague Dawley rats (n = 24) were divided into 6 groups (n = 4) as control, PID, prophylactic (low dose and high dose) and therapeutic group (low dose and high dose). PID model was constructed by implanting the rat cervix with mixed microbe (Escherichia Coli and Staphylococcus Aureus) solution. Prophylactic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting one day before PID induction and therapeutic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting 1 day after confirmation of PID model. Rats were sacrificed at the end of experiment and samples from upper genital tract were collected for ELISA, antioxidant assay and histopathological examination. According to results, obvious signs of inflammation and oxidative stress including infiltration of neutrophils and significantly raised levels of cytokines, and oxidative stress markers were observed in PID group when compared to control group. Punicalagin® significantly decreased the levels of IL-1ß, catalase and lipid peroxidation in both prophylactic and therapeutic groups when compared to PID group. Punicalagin® also decreased the infiltration of leucocytes in uterus of prophylactic and therapeutic group when compared to PID group, as determined by histological examination. On basis of these results, we concluded that Punicalagin® showed anti-inflammatory and antioxidant potential in rat model of pelvic inflammatory disease and could be used as possible therapeutic agent in treatment of PID.

Novel benzimidazole derivatives as effective inhibitors of prolyl oligopeptidase: synthesis, in vitro and in silico analysis.

Background: This research aims to discover novel derivatives having potential therapeutic applications in treating conditions related to prolyl oligopeptidase (POP) dysfunction. Method: Novel benzimidazole derivatives have been synthesized, characterized and screened for their in vitro POP inhibition. Results: All these derivatives showed excellent-to-good inhibitory activities in the range of IC50 values of 3.61 ± 0.15 to 43.72 ± 1.18 µM, when compared with standard Z-prolyl-prolinal. The docking analysis revealed the strong interactions between our compounds and the target enzyme, providing critical insights into their binding affinities and potential implications for drug development. Conclusion: The significance of these compounds in targeting POP enzyme offers promising prospects for future research in the field of neuropharmacology.

Investigation of the role of Cremophor RH 40 and Cremophor EL in the inhibition of efflux pump of Pseudomonas aeruginosa.

Background: There is increasing emphasis on restoring the efficacy of existing antibiotics instead of developing new ones. Objectives: This study aimed to determine the role of Cremophor EL and Cremophor RH40 in the inhibition of efflux pumps in MDR Pseudomonas aeruginosa strains. Methods: Efflux pump-active MDR strains of P. aeruginosa were identified and confirmed by flow cytometry. The identified efflux-active strains were further subjected to determination of the MIC of ciprofloxacin and the synergistic role of non-ionic surfactants (Cremophor EL and Cremophor RH40) along with ciprofloxacin. Results: Out of 30 samples, 6 strains displayed high efflux pump activity. Both Cremophor EL and Cremophor RH40 showed efflux pump inhibitory roles. A 4-fold reduction in the MIC values of ciprofloxacin was observed when Cremophor EL was used along with ciprofloxacin, while a 6-fold reduction was observed when Cremophor RH40 was used along with ciprofloxacin. Both compounds showed synergistic effects with ciprofloxacin, ticarcillin and meropenem when used in a 24-well plate efflux pump inhibitory assay. Conclusion: The inhibition of the efflux pump of MDR Pseudomonas aeruginosa by non-ionic surfactants, namely, Cremophor RH40 and Cremophor EL, provided the best strategy to restore the efficacy of ciprofloxacin.

Synthesis, characterization, Hirshfeld surface analysis, antioxidant and selective ß-glucuronidase inhibitory studies of transition metal complexes of hydrazide based Schiff base ligand.

The synthesis of N'-[(4-hydroxy-3-methoxyphenyl)methylidene] 2-aminobenzohydrazide (H-AHMB) was performed by condensing O-vanillin with 2-aminobenzohydrazide and was characterized by FTIR, high resolution ESI(+) mass spectral analysis, 1H and 13C-NMR. The compound H-AHMB was crystallized in orthorhombic Pbca space group and studied for single crystal diffraction analysis. Hirshfeld surface analysis was also carried out for identifying short interatomic interactions. The major interactions H…H, O…H and C…H cover the Hirshfeld surface of H-AHMB. The metal complexes [M(AHMB)n] where M = Co(II), Ni(II), Cu(II) and Zn(II) were prepared from metal chlorides and H-AHMB ligand. The bonding was unambigously assigned using FTIR and UV/vis analysis. The synthesized ligand H-AHMB and its metal complexes were studied for ß-glucuronidase enzyme inhibition. Surprisingly the metal complexes were found more active than the parent ligand and even the standard drug. Zn-AHMB shown IC50 = 17.3 ± 0.68 µM compared to IC50 = 45.75 ± 2.16 µM shown by D-saccharic acid-1,4-lactone used as standard. The better activity by Zn-AHMB implying zinc based metallodrug for the treatment of diseases associated with ß-glucuronidase enzyme. The DPPH radical scavenging activities were also studied for all the synthesized compounds. The Co-AHMB complex with IC50 = 98.2 ± 1.78 µM was the only candidate to scavenge the DPPH free radicals.

Synthesis, molecular docking and DFT analysis of novel bis-Schiff base derivatives with thiobarbituric acid for α-glucosidase inhibition assessment.

A library of novel bis-Schiff base derivatives based on thiobarbituric acid has been effectively synthesized by multi-step reactions as part of our ongoing pursuit of novel anti-diabetic agents. All these derivatives were subjected to in vitro α-glucosidase inhibitory potential testing after structural confirmation by modern spectroscopic techniques. Among them, compound 8 (IC50 = 0.10 ± 0.05 µM), and 9 (IC50 = 0.13 ± 0.03 µM) exhibited promising inhibitory activity better than the standard drug acarbose (IC50 = 0.27 ± 0.04 µM). Similarly, derivatives (5, 6, 7, 10 and 4) showed significant to good inhibitory activity in the range of IC50 values from 0.32 ± 0.03 to 0.52 ± 0.02 µM. These derivatives were docked with the target protein to elucidate their binding affinities and key interactions, providing additional insights into their inhibitory mechanisms. The chemical nature of these compounds were reveal by performing the density functional theory (DFT) calculation using hybrid B3LYP functional with 6-311++G(d,p) basis set. The presence of intramolecular H-bonding was explored by DFT-d3 and reduced density gradient (RGD) analysis. Furthermore, various reactivity parameters were explored by performing TD-DFT at CAM-B3LYP/6-311++G(d,p) method.