Isolation of ESBL-producing gram-negative bacteria and in silico inhibition of ESBLs by flavonoids

AbstractObjectiveTo evaluate nosocomial accounts of 426 extended spectrum β-lactamase (ESBL)-producing strains from 705 isolates of 9 pathogenic gram-negative bacteria in vitro. We analysed the genetic divergence of ESBLs by constructing a phylogenetic tree and modelled flavonoid inhibition of ESBLs with in silico molecular docking to determine effective control options.MethodsNine ESBL-producing bacteria were isolated from urine samples and their antibiograms were determined by the disc-diffusion method. Comparative models of the 9 ESBL enzymes were generated computationally using reference sequences, and validated by Ramachandran plots. Molecular docking with 11 flavonoids was conducted against the ESBL models.ResultsIsolated strains were floridly multidrug-resistant. From the docking study, the predicted minimum energy value of amikacin was −8.108 kcal/mol against the wild type TEM-1 ESBL of Acinetobacter baumannii, while the docking value against the mutant type Escherichia coli was −7.388 kcal/mol. The docking scores obtained corroborated the in vitro results showing that the antibiotic was incapable of controlling the ESBL of the mutant strain. Among 11 flavonoids tested against the mutant ESBL of E. coli, epigallocatechin 3-gallate and eriodictyol, with docking scores of −9.448 and −8.161 kcal/mol, respectively, were the most effective, with drug-likeness scores of 0.39 and 1.37, respectively, compared to 1.03 for amikacin.ConclusionDocking scores and drug-likeness scores indicated that flavonoids are compelling alternative antimicrobial agents that could serve as complementary therapy for newly arising ESBL-producing bacteria. Phylogenetic tree analysis elucidated the genetic relationship of the 9 ESBL serotypes

In vitro antibacterial efficacy of plants used by an Indian aboriginal tribe against pathogenic bacteria isolated from clinical samples

AbstractObjectivesTo evaluate antibacterial efficacies of 21 medicinal plants used by an Indian aboriginal tribe against infectious diseases caused by bacteria isolated from clinical samples.MethodsStandard biochemical procedures were followed for identifying bacteria that were isolated from several clinical samples. All of the bacterial strains were subjected to antibiotic sensitivity tests by Kirby–Bauer's disc diffusion method. From antibiograms of isolated Gram-positive and Gram-negative bacteria, it was discernible that samples were multidrug resistant (MDR). The methanol leaf-extract of Solanum xanthocarpum was subjected to thin layer chromatography (TLC) for phytochemical analysis. Molecular docking of β-lactamase enzyme of Escherichia coli with phytochemicals of S. xanthocarpum was performed to locate effective compounds.ResultsThe most effective 5 plants, which caused the size of the zone of inhibition to range from 21 to 27 mm, were Buchanania latifolia, Careya arborea, Ocimum tenuiflorum, Senna alata and S. xanthocarpum, for MDR bacteria. S. xanthocarpum had the lowest MIC value of 0.67 mg/ml and the lowest MBC value of 1.51 mg/ml against E. coli. In the TLC study, 9 spots of methanol leaf-extract of S. xanthocarpum were recorded with two solvent systems. The phytochemicals of S. xanthocarpum, solasodine and stigmasterol glucoside had the highest docking score values, −10.868 kcal/mol and −10.439 kcal/mol, respectively, against β-lactamase.ConclusionThis study could prove in vitro antimicrobial efficacy of 5 uncommon plants against MDR pathogenic bacteria. Solasodine and stigmasterol glucoside were computationally recorded as the best controlling chemicals from the plant S. xanthocarpum

Natural compounds isolated from African mistletoes (loranthaceae) exert anti-inflammatory and acetylcholinesterase inhibitory potentials : in vitro and in silico studies

DATA AVAILABILITY STATEMENT: All data generated or analysed during this study are included in this published article.Please read abstract in article.The Central University of Technology operational expenses and the National Research Foundation (NRF) of South Africa.https://www.mdpi.com/journal/applsciParaclinical Science

Computational attempts for synthesis of potent antibacterial sulfamethoxazole-monocyclic terpenes conjugates

To develop 6 conjugate agents of the moribund antibiotic sulfamethoxazole (SMZ) joined to 6 individual monoterpenes, followed by protocols of medicinal chemistry as potent antibacterials, against multidrug resistant (MDR) human gruesome pathogenic bacteria. Antibacterial activities of the proposed conjugates were ascertained by the ‘prediction of activity spectra of substances’ (PASS) program. Drug-likeness parameters and toxicity profiles of conjugates were standardized with the Lipinski rule of five, using cheminformatic tools, Molsoft, molinspiration, OSIRIS and ProTox. Antibacterial activities of individual chemicals and conjugates were examined by targeting the bacterial folic acid biosynthesis enzyme, dihydropteroate synthases (DHPSs) of bacteria, Bacillus anthracis, Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae and Mycobacterium tuberculosis, with 3D structures of DHPSs from protein data bank. According to the PASS program, biological spectral values of conjugate-2, conjugate-5 and conjugate-6 were ascertained effective with ‘probably active’ or ‘Pa’ value > 0.5, for anti-infective and an- tuberculosic activities. Using molecular docking against 5 cited bacterial DHPSs, effective docking scores of 6 monoterpenes in the specified decreasing order (kcal/mol): −9.72 (eugenol against B. anthracis), −9.61 (eugenol against S. pneumoniae), −9. 42 (safrol, against B. anthracis), −9.39 (thymol, against M. tuberculosis), −9.34 (myristicin, against S. pneumoniae) and −9.29 (thymol, against B. anthracis); whereas the lowest docking score of SMZ was -8.46 kcal/mol against S. aureus DHPS. Similarly, effective docking scores of conjugates were as specified (kcal/mol.): −10.80 (conjugate-4 consisting SMZ + safrol, against M. tuberculosis), −10.78 (conjugate-5 consisting SMZ + thymol, against M. tuberculosis), −10.60 (conjugate- 5 against B. anthracis), −10.26 (conjugate-2 consisting SMZ + eugenol, against M. tuberculosis), −10.25 (conjugate-5, against S. aureus) and −10.19 (conjugate-2 against S. pneumoniae. Conjugates-2 and -5 were the most effective antibacterials based on Lipinski rule of five with lethal doses 3471 and 3500 mg/kg, respectively and toxicity class levels. Conjugate-2 and conjugate-5 were more effective than individual monoterpenes and SMZ, against pathogenic bacteria. Synthesis, characterization and in vitro antibacterial study with acute toxicity testing for Wister rat model of the conjugate-5 could land at success in the recorded computational trial and it could be promoted for synthesis in the control of MDR bacteria

Anticancer Activities of Mushrooms: A Neglected Source for Drug Discovery

Approximately 270 species of mushrooms have been reported as potentially useful for human health. However, few mushrooms have been studied for bioactive compounds that can be helpful in treating various diseases. Like other natural regimens, the mushroom treatment appears safe, as could be expected from their long culinary and medicinal use. This review aims to provide a critical discussion on clinical trial evidence for mushrooms to treat patients with diverse types of cancer. In addition, the review also highlights the identified bioactive compounds and corresponding mechanisms of action among the explored mushrooms. Furthermore, it also discusses mushrooms with anticancer properties, demonstrated either in vitro and/or in vivo models, which have never been tested in clinical studies. Several mushrooms have been tested in phase I or II clinical trials, mostly for treating breast cancer (18.6%), followed by colorectal (14%) and prostate cancer (11.6%). The majority of clinical studies were carried out with just 3 species: Lentinula edodes (22.2%), Coriolus versicolor, and Ganoderma lucidum (both 13.9%); followed by two other species: Agaricus bisporus and Grifola frondosa (both 11.1%). Most in vitro cell studies use breast cancer cell lines (43.9%), followed by lung (14%) and colorectal cancer cell lines (13.1%), while most in vivo animal studies are performed in mice tumor models (58.7%). Although 32 species of mushrooms at least show some promise for the treatment of cancer, only 11 species have been tested clinically thus far. Moreover, most clinical studies have investigated fewer numbers of patients, and have been limited to phase III or IV. Therefore, despite the promising preclinical and clinical data publication, more solid scientific efforts are required to clarify the therapeutic value of mushrooms in oncology

Nano-technology platforms to increase the antibacterial drug suitability of essential oils: A drug prospective assessment

A huge number of plant-derived essential oils (EOs) are reported to have lots of ethnomedicinal and biological properties with excellent antibacterial activities. Approximately three hundred EOs (ajowan, anise, basil, camphor, chamomile, clove, citronella, coriander, cumin, eucalyptus, lavender, lemon, orange, peppermint, thyme oils, etc.) are documented under economic class based on commercial and pharmaceutical values. However, most active crude EOs and their constituents like carvacrol, eugenol, geraniol, linalool, thymol, 1,8-cineole, etc. are not found in mainstream drug development modules due to their low solubility, poor bioavailability, and rapid volatility profiles, which reduce their potency, half-life, and pharmacokinetics to achieve the ideal drug-ability profiles. To improve the mainstream use of EOs via nanotechnology, we first gathered more information on plant sources, extraction methods, antibacterial potency with mode of action, and the economic importance of EOs. Further, various nanotechnology platforms, such as nanocarriers, nanoemulsions, liposomes, and cyclodextrins with chemical structure conjugation concept with relevant examples were described. Technically, through optimization in particle size and morphology via a nanotechnology platform, EOs enhance the potency without losing any sensitive properties, easily penetrate and cross the bacterial cell membrane, protect from rapid volatility by coating biocompatible materials, improve the aqueous solubility, improve bioavailability, ensure sustainable release, etc. We hope that the detailed analyses of EOs and nanotechnology platforms will encourage academic and pharmaceutical researchers to use antibacterials by overcoming inadequate drug-ability profiles as potent agents in drugs, food, nutrition, beverages, packaging, and coating materials

Synthesis of novel thymol derivatives against MRSA and ESBL producing pathogenic bacteria

<p>Twelve substituted aryl-azo-thymol derivatives (<b>4a</b> to <b>4 l</b>) were synthesized and characterized by several spectral techniques such as, FTIR, UV-vis, proton NMR, Mass spectrometry and elemental analysis. Antimicrobial activities were evaluated by agar-well diffusion method against isolated MRSA, ESBL-producing pathogenic bacteria and antifungal resistant fungi, <i>in vitro</i>. In addition, drug likeness properties of derivatives were assessed through bioinformatic tools such as, PASS prediction, molecular docking and Lipinski rules of five, along with determination of toxic nature and LD₅₀ values. Among 12 derivatives, <b>4a</b>, <b>4b</b>, <b>4c</b>, <b>4 g, 4i, 4j</b> and <b>4 k</b> had significant antibacterial and antifungal activities with minimum inhibitory concentration values, 40 to 80 μg/ml. Moreover, the docking scores of derivatives were −8.27 to −11.44 kcal/mol, against 4 bacterial targets and −9.45 to −12.49 kcal/mol against 2 fungal targets. Thus, from <i>in vitro</i> and <i>in silico</i> studies, thymol derivatives had control of MRSA, ESBL-producing bacteria and antifungal resistant fungi.</p

In vitro antibacterial activity of crude extracts of 9 selected medicinal plants against UTI causing MDR bacteria

Urinary tract infection (UTI) has become a more grievous problem today, due to multidrug resistance of infecting Gram-positive (GP) and Gram-negative (GN) bacteria, sometimes even with multiple infections. This study examines effectivity of 9 tropical flowering plants (Anogeissus acuminata, Azadirachta indica, Bauhinia variegata, Boerhaavia diffusa, Punica granatum, Soymida febrifuga, Terminalia chebula, Tinospora cordifolia and Tribulus terrestris) for possible use as source of antimicrobials for multidrug resistant (MDR) bacteria, along with main-stream antibiotics. Pathogenic bacteria were isolated from urine samples of patients attending and admitted in the hospital. Antibiograms of 11 isolated bacteria (GPs, Enterococcus faecalis and Staphylococcus aureus; and GNs, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris and Pseudomonas aeruginosa) were ascertained by the disc-diffusion method, and antibacterial effectivity of plant extracts was monitored by the agar-well diffusion method. Isolated bacteria were floridly MDR to most antibiotics of the day. Methanol extracts of 9 plants were used, and extracts of 3 plants, A. acuminata, P. granatum and S. febrifuga at least caused 25–29 mm as the maximum size of zone of inhibition on bacterial lawns. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of methanol extracts of 9 plants were recorded. The methanol extract of A. acuminata had 0.29 mg/ml as the lowest MIC value and 0.67 mg/ml as the lowest MBC value, against MDR S. aureus, signifying effectivity; but, it had the highest MIC value of 3.41 mg/ml. and the highest MBC value of 4.27 mg/ml for most other MDR bacteria including E. coli. Qualitative phytochemical analysis was done for these 9 plants and information on leading phytochemicals was presented retrieved from PubChem database. Thus, three effective-most plants in controlling MDR-UTI bacteria in vitro were A. acuminata, P. granatum and S. febrifuga, which can be promoted as complementary medicine

Computer-aided synthesis of dapsone-phytochemical conjugates against dapsone-resistant Mycobacterium leprae

Abstract: Leprosy continues to be the belligerent public health hazard for the causation of high disability and eventual morbidity cases with stable prevalence rates, even with treatment by the on-going multidrug therapy (MDT). Today, dapsone (DDS) resistance has led to fear of leprosy in more unfortunate people of certain developing countries. Herein, DDS was chemically conjugated with five phytochemicals independently as dapsone-phytochemical conjugates (DPCs) based on azo-coupling reaction. Possible biological activities were verified with computational chemistry and quantum mechanics by molecular dynamics simulation program before chemical synthesis and spectral characterizations viz., proton-HNMR, FTIR, UV and LC-MS. The in vivo antileprosy activity was monitored using the ‘mouse-foot-pad propagation method’, with WHO recommended concentration 0.01% mg/kg each DPC for 12 weeks, and the host-toxicity testing of the active DPC4 was seen in cultured-human-lymphocytes in vitro. One-log bacilli cells in DDS-resistant infected mice footpads decreased by the DPC4, and no bacilli were found in the DDS-sensitive mice hind pads. Additionally, the in vitro host toxicity study also confirmed that the DCP4 up to 5,000 mg/L level was safety for oral administration, since a minor number of dead cells were found in red color under a fluorescent microscope. Several advanced bioinformatics tools could help locate the potential chemical entity, thereby reducing the time and resources required for in vitro and in vitro tests. DPC4 could be used in place of DDS in MDT, evidenced from in vivo antileprosy activity and in vitro host toxicity study