Effectiveness of early pharmaceutical interventions in symptomatic COVID-19 patients: A randomized clinical trial.

Objective: We assessed the effectiveness of oral Hydroxychloroquine (HC), Azithromycin (AZ) and Oseltamivir (OS), alone or combined, among patients hospitalized with mildly symptomatic coronavirus infectious disease (COVID-19). Methods: Following the approval of the National Bioethics Committee and prospective registration (clinicaltrials.gov NCT04338698), a multicenter randomized clinical trial of adaptive design was conducted at 10 multispecialty hospitals in Pakistan. Patients were randomized into seven treatment groups. Starting April 15, 2020, consenting, eligible, otherwise healthy adult patients or those with co-morbidities under control, were recruited if they presented with mildly symptomatic COVID-19 (scored 3 on a 7-point ordinal scale anchored between 1 = not hospitalized, able to undertake normal activities, to 7 = death) confirmed by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). Two primary outcomes were assessed by day seven: Turning qRT-PCR negative; and clinical improvement of two points from the baseline. Outcome rates were compared using a chi-square test. Multiple imputations were applied to handle missing data. An interim data analysis was carried out on July 19, 2020, following which the study continued without treatment group changes. Data Safety and Monitoring Board advised to stop recruitment due to its futility on January 18, 2021. Results: Of 471 patients randomized, a total of 426 (90.4%) completed the follow-up for primary outcomes. Based on imputed data analyses at day seven: Total qRT-PCR negative cases were 137/471 (29%, 95% CI 25.0 - 33.4). By day seven, a total of 111/471 (23.5%, 95% CI 19.8 - 27.6) showed clinical improvement. No serious or non-serious adverse event was reported. Conclusions: Among patients with mild COVID-19, there was no statistically significant difference in the effectiveness of oral antimalarial, antiviral, or antibiotic treatments.Clinicaltrials.gov ID: NCT04338698.

Datura suaveolens and Verbena tenuisecta mediated silver nanoparticles, their photodynamic cytotoxic and antimicrobial evaluation.

Biogenic production of nanoparticles is eco-friendly, less expensive method with various medical and biological applications. Nanotechnology along with photodynamic therapy is gaining tremendous importance with enhanced efficacy. The present work was aimed to evaluate methanolic extracts and nanoparticles of two selected plants (Datura suavolens and Verbina tenuisecta) for cytotoxic photodynamic, antioxidant and antimicrobial study. Both extract and silver (5 mM) nanoparticles of Datura plant showed significant activities against bacterial strains. Maximum ZOI of 27.3 ± 1.6 mm was observed with nanoparticles of Datura branches with minimum inhibitory (MIC) value of 32 µg/ml. In case of antifungal and antioxidant assay samples were moderately active. Silver nanoparticles and extracts were effective against rhabdomyosarcoma cell line with lowest IC50 value of 42.5 ± 0.6 µg/ml and percent viability of 25.6 ± 1.3 of Verbena tenuisecta. However, nanoparticles of Datura leaves and branches were more potent with IC50 value of 2.4 ± 0.9 µg/ml and 7.8 ± 1.1 µg/ml respectively. The result of photodynamic study showed that efficacy of photosensitizer was enhanced and percent viability reduced when nanoparticles used as an adjunct. The color change and UV spectra (415‒425 nm) indicated the production of nanoparticles. Fourier transform infrared spectroscopy (FTIR) spectra showed presence of different functional groups e.g., hydroxyl, carbonyl and amino. Nanoparticles are sphenoid in morphology and size ranges between 20-150 nm. Current study showed these silver nanoparticles can be used as cytotoxic agent in photodynamic therapy and can play a critical role to establish medicinal potential of selected plants.

Antibacterial activity and characterization of zinc oxide nanoparticles synthesized by microalgae.

Biosynthesis of zinc oxide nanoparticles (ZnO-NPs) using microalgae is novel and cost-effective approach. We studied production, molecular characterization, and antibacterial activity. Filtrates of isolated microalgae strain ZAA1 (MF140241), ZAA2 (MF114592) and ZAA3 (MF114594) were used. Incubation of these strains in 5mM solution of zinc nitrate was resulted in the synthesis of ZnO-NPs. Fourier-transform infrared, UV-visible spectroscopy and scanning electron microscopy were used to characterize the nanoparticles. Significant antibacterial activity of ZnO-NPs was measured against Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Klebsiella pneumoniae and Citrobacter freundii. The microalgae mediated ZnO-NPs production is a successful procedure that can be used in a wide range of biomedical applications.

Synthesis, antimicrobial, antioxidant, cytotoxic, antiurease and molecular docking studies of N-(3-trifluoromethyl)benzoyl-N'-aryl thiourea derivatives.

An irrefutable advancement has been noted for the infectious diseases caused due to ureolytic bacteria through the development of various drugs. Keeping in mind the extremely valuable synthetic utility and medicinal significance of thiourea derivatives, synthesis of new 3-trifluoromethyl benzoic acid thiourea derivatives (3a-j) were carried out. The biological potential of all compounds in terms of antimicrobial, antioxidant, cytotoxic and antiurease activities were studied. The compounds 3a, 3c and 3i with dichloro and methoxy groups substitution on the aryl group showed significant activity against all strain of bacteria while moderate to no activity was observed in remaining compounds. Whereas the antifungal evaluation showed that all compounds were active againts C. Albican and no activity was observed against C. Prapsilosis. The cytotoxic findings revealed the non-toxic nature of these compounds as IC50 values of majority of the compounds are above 100 µm except for compounds 3f and 3g. In addition, these compounds exhibited better antioxidant potential as 100 µm concentration inhibited >50% reactive oxygen species (ROS) production except compounds 3e, 3f and 3j. The compound 3a proved to be the most potent urease inhibitor showing the highest enzyme % inhibition (93.1%) with IC50 value of 8.17 ±â€¯0.24 µM and found more active as compare to standard followed by compound 3e (92.6%), 3h (91.6%), 3d (90.8%), 3b (90.6%) and 3f (90.0%) with their respective IC50 values. All the synthesized compounds were docked into the binding cavity of Urease (PDB ID: 4ubp). The most active compound 3a was also ranked as top on the docking score as it was found to show valuable interactions with the target protein along with good docking scores. Hence our results revealed that the synthesized compounds have potential to be used as potent urease inhibitors after further detailed mechanistic studies.

Implications of self-medication among medical students-A dilemma.

OBJECTIVE: To evaluate the knowledge, attitude and practice of self-medication in medical undergraduate students. METHODS: This cross-sectional questionnaire-based survey was conducted from January to June, 2017, among undergraduate students of Ayub Teaching Hospital, Women Medical College, International Medical College and Frontier Medical College in Abbottabad, Pakistan. The sample comprised students of first, second, third, fourth and fifth professional year. Data was collected using self-generated questionnaire. RESULTS: Of the 400 subjects approached, 300(75%) returned the questionnaire fully completed. Of them, 208 (69.3%) were females and 92(30.66%) were males. The most common age group was 22-25 years 182(60.7%). Self-medication was found to be prevalent among 297(99%) subjects and 139(46.3%) respondents had practised self-medication in the preceding 6 months more than two times. Over-the-counter drugs were commonly used for the self-medication in 295(98.3%) cases. Overall, 285(95%) respondents had a positive attitude towards self-medication. Media was found to be the most common source of information for 93(31%) cases. CONCLUSIONS: High prevalence of self-medication was noticed, with over-the-counter drugs being the most commonly used. Proper educational awareness programmes about self-medication can control the issue.

Endophytic fungi associated with Taxus fuana (West Himalayan Yew) of Pakistan: potential bio-resources for cancer chemopreventive agents.

CONTEXT: Endophytic fungi, being a prolific source of bioactive secondary metabolites, are of great interest for natural product discovery. OBJECTIVE: Isolation and partial characterization of endophytic fungi inhabiting the leaves and woody parts of Taxus fuana Nan Li & R.R. Mill. (Taxaceae) and evaluation of biological activity. MATERIALS AND METHODS: Endophytic fungal isolates were identified by molecular analysis of internal transcribed spacer (ITS) regions of 18S rDNA. Extracts of the endophytic fungi cultured on potato dextrose agar and modified medium were evaluated using cancer chemoprevention bioassays [inhibition of TNF-α-induced NFκB, aromatase and inducible nitric oxide synthase (iNOS); induction of quinone reductase 1 (QR1)] and growth inhibition with MCF-7 cells. RESULTS: Nine of 15 fungal isolates were identified as belonging to Epicoccum, Mucor, Penicillium, Chaetomium, Paraconiothriym, Plectania or Trichoderma. Five of the 15 extracts inhibited NFκB activity (IC50 values ranging between 0.18 and 17 µg/mL) and five inhibited iNOS (IC50 values ranging between 0.32 and 12.9 µg/mL). In the aromatase assay, only two isolates mediated inhibition (IC50 values 12.2 and 10.5 µg/mL). With QR1 induction, three extracts exhibited significant activity (concentrations to double activity values ranging between 0.20 and 5.5 µg/mL), and five extracts inhibited the growth of MCF-7 cells (IC50 values ranging from 0.56 to 17.5 µg/mL). Six active cultures were derived from woody parts of the plant material. CONCLUSION: The endophytic fungi studied are capable of producing pharmacologically active natural compounds. In particular, isolates derived from the wood of Taxus fuana should be prioritized for the isolation and characterization of bioactive constituents.

PRODUCTION OF ANTIMICROBIAL PEPTIDES BY EPICOCCUM SP. NFW1: AN ENDOPHYTE OF TAXUS FAUNA.

An endophytic fungus NFWI, possessing antimicrobial activity against bacterial and fungal pathogens, was isolated from indigenous Taxus fauna. Phylogenetic analysis coupled with cultural and morphological characteristics revealed that endophyte NFWI closely resembles Epicoccum sp. It showed optimum growth and antimicrobial activity in mineral salt medium TM, incubation temperature 250C, incubation time 15 days and pH 6.5. Antimicrobial peptides were precipitated with 80% ammonium sulfate and expressed significant inhibitory effect against Staphylococcus aureus (ATCC6538) and Candida albicans (CI.I 4043). It also inhibited growth of Streptomyces 85E in hyphae formation inhibition assay showing potential as protein kinase inhibitor. Gel filtration chromatography on Sephadex G-75, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis resolved the crude precipitate into three fractions of molecular mass 32 kDa, 44 kDa and 70 kDa. The study concludes that endophytic fungi associated with indigenous Taxus species possess promising antimicrobial activities and should be exploited as source of novel antimicrobial agents.

EPICOCCUM SP., AN EMERGING SOURCE OF UNIQUE BIOACTIVE METABOLITES.

Fungi are playing a vital role for producing natural products, most productive source of lead compounds in far reaching endeavor of new drug discovery. Epicoccum fungus is known for its potential to produce diverse classes of biologically active secondary metabolites. The intent of this review is to provide detailed information about biology and chemistry of Epicoccum fungus. Most of the fungus metabolites showed cytotoxic, anticancer, antimicrobial and anti-diabetic activities. The literature given encompases the details of isolation of different unusual and unique secondary metabolites, their chemical nature and biological activities find out Epicoccum spp., a potential source of lead molecules.

Determination of the absolute configuration of chaetoviridins and other bioactive azaphilones from the endophytic fungus Chaetomium globosum.

Chemical investigation of an endophytic fungus Chaetomium globosum isolated from leaves of Wikstroemia uva-ursi led to the isolation of two new azaphilones, chaetoviridins J and K (1 and 3), along with five known derivatives (2 and 4-7). The structures of azaphilones were determined by NMR, X-ray diffraction, Mosher's method, and CD analysis. The isolated compounds were evaluated for their cancer chemopreventive-potential based on their abilities to inhibit tumor necrosis factor alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB). Compounds 4, 5, 7, and synthetic 8 and 9 inhibit nitric oxide (NO) production with IC50 values in the range of 0.3-5.8 µM. Compounds 4, 5, and 9 also displayed (TNF-α)-induced NF-κB activity with IC50 values in the range of 0.9-5.1 µM.

PHARMACOLOGICAL ACTIVITIES OF PROTOCATECHUIC ACID.

Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a simple phenolic acid. It is found in a large variety of edible plants and possesses various pharmacological activities. This article aims to review the modern trends in phytochemical isolation and extraction of PCA from plants and other natural resources. Moreover, this article also encompasses pharmacological and biological activities of PCA. It is well known to have anti-inflammatory, antioxidant, anti-hyperglycemia, antibacterial, anticancer, anti-ageing, anti-athro- genic, anti-tumoral, anti-asthma, antiulcer, antispasmodic and neurological properties.

SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL AND PHYTOTOXIC SCREENING OF 1-AROYL-3,5-DIARYLPYRAZOLINE DERIVATIVES.

Pyrazolines are biologically and pharmaceutically very active scaffolds. Derivatives of. (3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)(phenyl)methanone were synthesized by the cyclization of chalcones (1a-c) with substituted benzyl hydrazides (2a-e) using a few drops of piperidine as catalyst. Structures of all the synthesized compounds were confirmed by FTIR, 1H NMR, 13C NMR and mass spectrometric analysis. All the pyrazolines were subjected to antimicrobial and phytotoxic assays. Compound 3a and 3c showed maximum antimicrobial activities while all the synthesized compounds were active acc. to their phytotoxic assays.

Exploring the antimicrobial and cytotoxic potential of novel chloroquine analogues.

Aim: To synthesize novel chloroquine analogues and evaluate them for antimicrobial and cytotoxic potential. Methods: Novel analogues were synthesized from chloroquine by nucleophilic substitution reaction at the 4-amino position. Results: Analogue CS1 showed maximum antimicrobial potential (30.3 ± 0.15 mm zone) against Pseudomonas aeruginosa and produced a 19.2 ± 0.21 mm zone against Candida albicans, while CS0 produced no zone at the same concentration. Analogue CS9 has excellent cytotoxic potential (HeLa cell line), showing 100% inhibition (IC50 = 8.9 ± 1.2 µg/ml), compared with CS0 (61.9% inhibition at 30 µg/ml). Conclusion: These synthesized chloroquine analogues have excellent activity against different microbial strains and cervical cancer cell lines (HeLa) compared with their parent molecule.

Apoptosis-inducing and antitumor activity of neolignans isolated from Magnolia officinalis in HeLa cancer cells.

Two neolignans, 4'-methoxymagndialdehyde (1) and magnaldehyde B (2), were isolated from the stem bark of Magnolia officinalis (Magnoliaceae), evaluated for apoptosis-inducing effects in human cervical epitheloid carcinoma HeLa cells. The apoptosis-inducing activity of compounds 1 and 2 were assessed by DNA content using flow cytometric analysis. In the immunoblotting analysis, the treatment with 1 and 2 resulted in the cleavage of procaspase-8 and -3 and poly(ADP-ribose)polymerase into active forms. In addition, in vivo, the administration of 2 to Lewis lung carcinoma-inoculated mice evidenced a significant inhibition of tumor growth (volume) with reduction of 28.7% at concentration of 20 mg/kg, as compared with the control mice. These findings suggest that 2 can inhibit the proliferation of tumor cells, and might be an anti-tumoric agent.

Biosynthesis of silver nanoparticles using endophytic Fusarium oxysporum strain NFW16 and their in vitro antibacterial potential.

Nanotechnology has provided a platform for altering, modifying, and developing metal properties to nanoparticles with promising applications. This study aimed to produce functionalized and biocompatible silver nanoparticles (AgNPs) using cellular extracts of endophytic Fusarium oxysporum-NFW16 isolated from Taxus fauna and evaluate its antibacterial potential. Under optimized reaction conditions, well-dispersed and extremely stable AgNPs were synthesized in 1 hr. AgNPs were characterized through UV-visible spectrophotometry (at 423 nm), and scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The obtained AgNPs were spherical, monodispersed, and size was ~30-36.1 nm. Strong peaks of XRD (311), (220), (200), and (111) matched to silver plane's diffraction facets. FTIR spectra at 1,650, 2,950, and 1,400 cm-1 confirmed the capping of AgNPs with phenolic compounds and compounds having primary amines. The AgNPs showed 100 µg/ml of minimum inhibitory concentration against methicillin-resistant Staphylococcus aureus (MRSA). In addition, AgNPs showed a synergistic effect with both vancomycin and ciprofloxacin against MRSA (25%), Pseudomonas aeruginosa (50%), and pus isolated Escherichia coli (50%). Moreover, AgNPs impregnated cotton and bandage showed in vitro antibacterial potential against American Type Culture Collection and skin-associated clinical pathogenic bacteria. Findings showed that endophytic fungi are the potential source for AgNPs synthesis that are effective against multidrug-resistant bacteria and the development of antimicrobial textile finishes.

Anticandidal activity of green synthesised silver nanoparticles and extract loaded chitosan nanoparticles of Euphorbia prostata.

This study aimed to synthesize the silver nanoparticles (SNPs) and loaded chitosan nanoparticles (LCNPs) using Euphorbia prostata based on their anticandidal activity. Antioxidant capacity and the total phenolic and total flavonoid content of plant samples and synthesized nanoparticles (NPs) were also evaluated. SNPs and LCNPs were prepared, respectively using chemical reduction of silver salt solution and ionotropic gelation method. The anticandidal activity was assessed by broth micro-dilution method and the antioxidant activity was determined using free-radical scavenging assays. The synthesized NPs after the optimization process were found to be spherical with sizes ranging from 12 to 100 nm. Spectroscopic analysis of NPs showed the appearance of peaks in prescribed wavelength ranging between 402 and 493 nm. The synthesized NPs showed potent anticandidal activity compared to the free extract. The SNPs formulations NpEPM 7.5 and NpEPMR 7.5, showed significantly low MIC values ranging between 2 and 128 µg/mL. In the case of LCNPs, NpEPM (4:1) and NpEPME (4:1) also showed lower MIC values ranging from 32 to 256 µg/mL. The plant samples as well as NPs showed antioxidant potential. In addition, plant extracts and NPs possess the potent biological potential and can be further investigated through in vivo experiments.

Ligustrum lucidum Leaf Extract-Assisted Green Synthesis of Silver Nanoparticles and Nano-Adsorbents Having Potential in Ultrasound-Assisted Adsorptive Removal of Methylene Blue Dye from Wastewater and Antimicrobial Activity.

Present study was conducted to investigate the adsorption and ultrasound-assisted adsorption potential of silver nanoparticles (AgNPs) and silver nanoparticles loaded on chitosan (AgCS composite) as nano-adsorbents for methylene blue (MB) removal. AgNPs were synthesized using leaf extract of Ligustrum lucidum, which were incorporated on the chitosan's surface for modification. UV−Vis Spectroscopy, FTIR, XRD, SEM, and EDX techniques were used to confirm the synthesis and characterization of nanomaterials. Batch adsorption and sono-adsorption experiments for the removal of MB were executed under optimal conditions; for fitting the experimental equilibrium data, Langmuir and Freundlich's isotherm models were adopted. In addition, the antimicrobial potential of the AgNPs and AgCS were examined against selected bacterial and fungal strains. UV−Vis spectroscopy confirmed AgNPs synthesis from the leaf extract of L. lucidum used as a reducer, which was spherical as exposed in the SEM analysis. The FTIR spectrum illustrated phytochemicals in the leaf extract of L. lucidum functioning as stabilizing agents around AgNPs and AgCS. Whereas, corresponding crystalline peaks of nanomaterial, including a signal peak at 3 keV indicating the presence of silver, were confirmed by XRD and EDX. The Langmuir model was chosen as an efficient model for adsorption and sono-adsorption, which exposed that under optimum conditions (pH = 6, dye initial concentration = 5 mg L−1, adsorbents dosage = 0.005 g, time = 120 min, US power 80 W), MB removal efficiency of AgNPs was >70%, using ultrasound-assisted adsorption compared to the non-sonicated adsorption. Furthermore, AgNPs exhibited promising antibacterial potential against Staphylococcus aureus with the maximum zone of inhibition (14.67 ± 0.47 mm). It was concluded that the green synthesis approach for the large-scale production of metallic nanoparticles is quite effective and can be recommended for efficient and cost-effective way to eradicate dyes, particularly from textile wastewater.

Antioxidant, Cytotoxic, and Antimicrobial Potential of Silver Nanoparticles Synthesized using Tradescantia pallida Extract.

Silver nanoparticles have received much attention, due to their wide range of biological applications as an alternative therapy for disease conditions utilizing the nanobiotechnology domain for synthesis. The current study was performed to examine the antioxidant, anticancer, antibacterial, and antifungal potential of biosynthesized silver nanoparticles (TpAgNPs) using plant extract. The TpAgNPs were produced by reacting the Tradescantia pallida extract and AgNO3 solution in nine various concentration ratios subjected to bioactivities profiling. According to the current findings, plant extract comprising phenolics, flavonoids, and especially anthocyanins played a critical role in the production of TpAgNPs. UV-visible spectroscopy also validated the TpAgNP formation in the peak range of 401-441 nm. Further, the silver ion stabilization by phytochemicals, face-centered cubic structure, crystal size, and spherical morphology of TpAgNPs were analyzed by FTIR, XRD, and SEM. Among all TpAgNPs, the biosynthesized TpAgNP6 with a medium concentration ratio (5:10) and the plant extract had effective antioxidant potentials of 77.2 ± 1.0% and 45.1 ± 0.5% free radical scavenging activity, respectively. The cytotoxic activity of TpAgNP6 in comparison to plant extract for the rhabdomyosarcoma cell line was significantly the lowest with IC50 values of 81.5 ± 1.9 and 90.59 ± 1.6 µg/ml and cell viability % of 24.3 ± 1.62 and 27.4 ± 1.05, respectively. The antibacterial and antifungal results of TpAgNPs revealed significant improvement in comparison to plant extract, i.e., minimum inhibition concentration (MIC) 64 µg/ml against Gram-negative Pseudomonas aeruginosa while, in the case of antifungal assay, TpAgNP6 was active against Candida parapsilosis. These TpAgNPs play a crucial role in determining the therapeutic potential of T. pallida due to their biological efficacy.

Exploring 3-hydroxyflavone scaffolds as mushroom tyrosinase inhibitors: synthesis, X-ray crystallography, antimicrobial, fluorescence behaviour, structure-activity relationship and molecular modelling studies.

To explore new scaffolds as tyrosinase enzyme inhibitors remain an interesting goal in the drug discovery and development. In due course and our approach to synthesize bioactive compounds, a series of varyingly substituted 3-hydroxyflavone derivatives (1-23) were synthesized in one-pot reaction and screened for in vitro against mushroom tyrosinase enzyme. The structures of newly synthesized compounds were unambiguously corroborated by usual spectroscopic techniques (FTIR, UV-Vis, 1H-, 13C-NMR) and mass spectrometry (EI-MS). The structure of compound 15 was also characterized by X-ray diffraction analysis. Furthermore, the synthesized compounds (1-23) were evaluated for their antimicrobial potential. Biological studies exhibit pretty good activity against most of the bacterial-fungal strains and their activity is comparable to those of commercially available antibiotics i.e. Cefixime and Clotrimazole. Amongst the series, the compounds 2, 4, 5, 6, 7, 10, 11, 14 and 22 exhibited excellent inhibitory activity against tyrosinase, even better than standard compound. Remarkably, the compound 2 (IC50 = 0.280 ± 0.010 µg/ml) was found almost sixfold and derivative 5 (IC50 = 0.230 ± 0.020 µg/ml) about sevenfold more active as compared to standard Kojic acid (IC50 =1.79 ± 0.6 µg/ml). Moreover, these synthetic compounds (1-23) displayed good to moderate activities against tested bacterial and fungal strains. Their emission behavior was also investigated in order to know their potential as fluorescent probes. The molecular modelling simulations were also performed to explore their binding interactions with active sites of the tyrosinase enzyme. Limited structure-activity relationship was established to design and develop new tyrosinase inhibitors by employing 2-arylchromone as a structural core in the future. Communicated by Ramaswamy H. Sarma.

Terpyridine-metal complexes: effects of different substituents on their physico-chemical properties and density functional theory studies.

A series of different substituted terpyridine (tpy)-based ligands have been synthesized by Kröhnke method. Their binding behaviour was evaluated by complexing them with Co(II), Fe(II) and Zn(II) ions, which resulted in interesting coordination compounds with formulae, [Zn(tpy)2]PF6, [Co(tpy)2](PF6)2, [Fe(tpy)2](PF6)2 and interesting spectroscopic properties. Their absorption and emission behaviours in dilute solutions were investigated in order to explain structure-property associations and demonstrate the impact of different aryl substituents on the terpyridine scaffold as well as the role of the metal on the complexes. Photo-luminescence analysis of the complexes in acetonitrile solution revealed a transition from hypsochromic to bathochromic shift. All the compounds displayed remarkable photo-luminescent properties and various maximum emission peaks owing to the different nature of the functional groups. Furthermore, the anti-microbial potential of ligands and complexes was evaluated with docking analyses carried out to investigate the binding affinity of terpyridine-based ligands along with corresponding proteins (shikimate dehydrogenase and penicillin-binding protein) binding sites. To obtain further insight into molecular orbital distributions and spectroscopic properties, density functional theory calculations were performed for representative complexes. The photophysical activity and interactions between chromophore structure and properties were both investigated experimentally as well as theoretically.

Chemical synthesis of chitosan/silver nanocomposites films loaded with moxifloxacin: Their characterization and potential antibacterial activity.

This article reports moxifloxacin (Mox)-loaded nanocomposite films (CSN) of chitosan and chemically reduced silver (Ag). The synthesis of silver nanoparticles was confirmed by specific surface plasmon resonance (SPR) peaks detected via UV-Visible spectroscopy at the wavelength range of 400-450 nm. The embedded Mox was chemically characterized and kinetically analyzed for in-vitro drug release and ex-vivo drug permeation through rat skin. The prepared films presented higher swelling ratio and lower tensile strength (TS) and better elongation at break (EB) than control formulation (pure chitosan film). All the prepared Mox-loaded, non-crosslinked formulations presented sustained release of drug up to 12 h while slow and prolonged drug release up to 36 h was observed in Mox-loaded crosslinked CSN films. Drug permeation studies indicated that the maximum cumulative amount of Mox permeated (%) among Mox-loaded, non-crosslinked CSN films was displayed by CSM1 (57.79%); while in case of Mox-loaded, crosslinked CSN films, the highest drug permeation was presented by CSM18 (62.87%) in 24 h. The antibacterial efficacy of the prepared films was tested in-vitro against S. aureus (ATCC # 6538), P. aeruginosa (ATCC # 9721) and two clinically isolated strains of methicillin resistant S. aureus (MRSA). CSN films presented excellent against the all the selected strains with antibacterial potential being highest against S. aureus. In summary, the promising antibacterial potential of the CSN films recommend its biomedical application for use in wound dressing.