Thymoquinone inhibits biofilm formation and has selective antibacterial activity due to ROS generation

Nigella sativa Oil Mouth Rinse Improves Chemotherapy-Induced Oral Mucositis in Patients with Acute Myeloid Leukemia

Objective

The present study aims at evaluating the beneficial effect of Nigella sativa (NS) oil mouth rinse in the management of chemotherapy- (CT-) induced oral mucositis (OM) in patients with acute myeloid leukemia (AML).

Methods

Fifty-four AML patients were participated in this study and randomly allocated to either the test group or a control group. The patients of the test group received NS oil mouth rinse during 28-day CT, while the participants of the control group received a "magic mouthwash" formula. The primary outcome of this study was the incidence and severity of CT-induced OM in terms of erythema and ulcer. The secondary outcomes were the pain severity score, swallowing function, and the salivary concentrations of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α).

Results

NS oil mouth rinse attenuated the progression of CT-induced OM compared with the control formula (AUC = 5.9 vs. 38.4, P < 0.05) and significantly decreased the erythema and ulceration scores (AUC of total OMAS = 11.4 vs. 85.9, P < 0.001) compared with the magic mouthwash formula. It also reduced the pain score and enabled all the participants of this group to consume normal food during treatment. It significantly decreased salivary IL-6 (AUC = 7376 vs. 16599, P < 0.001), while the changes of TNF-α levels were not significant (AUC = 676.9 vs. 885.2, P > 0.05).

Conclusions

NS oil mouth rinse is effective in attenuating the severity of CT-induced OM and improves the pain and swallowing function in AML patients.

Influence of selected plant seeds on the performance, carcass characteristics, sensory evaluation, and economics of broiler chicken

The immergence of antibiotic resistance, in livestock especially poultry, led to the ban of antibiotics as a growth promoter in some part of the world. This brought about the investigations into the development of various alternatives to antibiotics that will not compromise the integrity of poultry products for safe consumption. Therefore, this study examined the possible impacts of selected plants seeds (pawpaw, mustard, and black cumin) as feed additives on the performance, carcass characteristics, and sensory evaluation of broilers. A total of 180 day-old Arbor Acre Plus chicks were randomly assigned to five treatments of four replicates in a completely randomized design. The five treatments were three plant seed additives: pawpaw (PPS), mustard (MUS), and black cumin (BCS), treatment without additives (CON, i.e., no plants seeds/medications), and treatment with medications and antibiotics (ANT). During the feeding trials that lasted for 8 weeks, body weight gain, feed intake, and feed conversion ratio (FCR) were considered performance data. At the end of the feeding trials, two birds per replicate were slaughtered for carcass parameters and sensory evaluation. Data collected were subjected to analysis of variance. Mustard seed (Brassica juncea) significantly (P = 0.018) supported carcass growth. Further, the highest feed intake was obtained in MUS while the lowest was obtained in CON birds. The PPS had higher (P = 0.013) BWG than in other treatments while the lowest was obtained in CON. Values of FCR were lowest (P = 0.15) in PPS while the highest in CON birds. Furthermore, MUS and PPS had significantly (P = 0.018) and (P = 0.03) higher live weight than CON and ANT, while MUS had higher dressed weight percentage than CON and ANT birds. Broiler meat under diet supplemented with black cumin was relatively found to be most acceptable while meat under mustard seed was the least acceptable. In contrast, the average cost realized per bird was obtained in PPS while the lowest was in CON and ANT. However, broiler diet supplemented with BCS brings about a corresponding decrease in percentage feeding cost reduction among plant supplements.

Inhibitory Effect of Thymoquinone on Listeria monocytogenes ATCC 19115 Biofilm Formation and Virulence Attributes Critical for Human Infection

This study aimed to determine the antimicrobial activity of thymoquinone (TQ) against Listeria monocytogenes, and to examine its inhibitory effects on biofilm formation, motility, hemolysin production, and attachment-invasion of host cells. The minimum inhibitory concentrations (MICs) of TQ against eight different L. monocytogenes strains ranged from 6.25-12.50 μg/mL. Crystal violet staining showed that TQ clearly reduced biofilm biomass at sub-MICs in a dose-dependent manner. Scanning electron microscopy suggested that TQ inhibited biofilm formation on glass slides and induced an apparent collapse of biofilm architecture. At sub-MICs, TQ effectively inhibited the motility of L. monocytogenes ATCC 19115, and significantly impacted adhesion to and invasion of human colon adenocarcinoma cells as well as the secretion of listeriolysin O. Supporting these findings, real-time quantitative polymerase chain reaction analysis revealed that TQ down-regulated the transcription of genes associated with motility, biofilm formation, hemolysin secretion, and attachment-invasion in host cells. Overall, these findings confirm that TQ has the potential to be used to combat L. monocytogenes infection.

Reactive Oxygen Species Production Is a Major Factor Directing the Postantibiotic Effect of Fluoroquinolones in Streptococcus pneumoniae

We studied the molecular mechanisms involved in the postantibiotic effect of the fluoroquinolones levofloxacin and moxifloxacin in Streptococcus pneumoniae Wild-type strain R6 had postantibiotic effects of 2.05 ± 0.10 h (mean ± standard deviation [SD]) and 3.23 ± 0.45 h at 2.5× and 10× MIC of levofloxacin, respectively. Moxifloxacin exhibited lower effects of 0.87 ± 0.1 and 2.41 ± 0.29 h at 2.5× and 10× MIC, respectively. Fluoroquinolone-induced chromosome fragmentation was measured at equivalent postantibiotic effects for levofloxacin (2.5× MIC) and moxifloxacin (10× MIC). After 2 h of drug removal, reductions were approximately 7-fold for levofloxacin and 3-fold for moxifloxacin, without further decreases at later times. Variations in reactive oxygen species production were detected after 4 to 6 h of drug withdrawals, with decreases ≥400-fold for levofloxacin and ≥800-fold for moxifloxacin at 6 h. In accordance, after 4 to 6 h of drug withdrawal, the levofloxacin-induced upregulation of the fatCDEB operon, introducing iron in the bacteria, decreased up to 2- to 3-fold, and the moxifloxacin-induced upregulation of several genes involved in the production of pyruvate was reduced 3- to 7-fold. In accordance, lower postantibiotic effects (up to 1 h) were observed in strain R6 ΔspxB, lacking the main enzyme involved in oxygen peroxide production, than in R6. Although no change in the recovery of chromosome fragmentation was observed between R6 and R6 ΔspxB, 3.5 × 10³-fold lower reactive oxygen species production was observed in R6 ΔspxB, without changes after drug removal. These results show that reactive oxygen species are the main factors directing the postantibiotic effect of levofloxacin and moxifloxacin in S. pneumoniae.

Thymoquinone loaded mesoporous silica nanoparticles retard cell invasion and enhance in vitro cytotoxicity due to ROS mediated apoptosis in HeLa and MCF-7 cell lines

Thymoquinone (TQ) loaded monodispersed mesoporous silica nanoparticles (TQ-MSNPs) with size of 188 ± 3 nm were prepared and characterized using DLS, TEM and FTIR. These TQ-MSNPs overcome the limitations of free TQ like hydrophobicity, low aqueous and photo stability and thus enhance its anticancer activity. In vitro release kinetics showed biphasic drug release where up to 50% was released in first 8 h and subsequently 98% released after 48 h. Enhanced cytotoxicity of TQ-MSNPs was observed against MCF-7 and HeLa cell lines as compared to free TQ. DAPI and Annexin V-FITC/PI staining confirmed the induction of apoptosis in cancer cells following treatment with TQ-MSNPs. Also, TQ-MSNPs exhibited enhanced anti-invasion properties against both cell lines as very low concentration of loaded TQ imparts similar benefits as free TQ. Both TQ and TQ-MSNPs exerted their cytotoxicity via reactive oxygen species (ROS) generation, as addition of an antioxidant NAC attenuated their killing activity.

Target identification and intervention strategies against amebiasis

Entamoeba histolytica is the etiological agent of amebiasis, which is an endemic parasitic disease in developing countries and is the cause of approximately 70,000 deaths annually. E. histolytica trophozoites usually reside in the colon as a non-pathogenic commensal in most infected individuals (90% of infected individuals are asymptomatic). For unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver where they cause hepatocellular damage. Amebiasis is usually treated either by amebicides which are classified as (a) luminal and are active against the luminal forms of the parasite, (b) tissue and are effective against those parasites that have invaded tissues, and (c) mixed and are effective against the luminal forms of the parasite and those forms which invaded the host's tissues. Of the amebicides, the luminal amebicide, metronidazole (MTZ), is the most widely used drug to treat amebiasis. Although well tolerated, concerns about its adverse effects and the possible emergence of MTZ-resistant strains of E. histolytica have led to the development of new therapeutic strategies against amebiasis. These strategies include improving the potency of existing amebicides, discovering new uses for approved drugs (repurposing of existing drugs), drug rediscovery, vaccination, drug targeting of essential E. histolytica components, and the use of probiotics and bioactive natural products. This review examines each of these strategies in the light of the current knowledge on the gut microbiota of patients with amebiasis.

Ampicillin Silver Nanoformulations against Multidrug resistant bacteria

The present study reported a single step synthesis of silver nanoparticles using ampicillin (Amp-AgNps), a second-generation β lactam antibiotic to get nanoformulation having dual properties that of antibiotic and silver. The Amp-AgNps was characterized by UV-VIS spectroscopy, TEM, XRD, FTIR and TGA. FTIR and TGA results suggested that amine group of Ampicllin reduce the metalic silver into nano form. These results were further validated by computational molecular dynamics simulation. The antibacterial potential of Amp-AgNps was investigated against sensitive and drug resistant bacteria. MIC of Amp-AgNps against 6 different bacterial strains were in the range of 3–28 µg/ml which is much lower than the MIC of ampicillin (12–720 µg/ml) and chemically synthesized silver nanoparticles (280–640 µg/ml). The repeated exposure to drugs may lead to development of resistance mechanism in bacteria against that drug, so the efficacy of Amp-AgNps after repeated exposure to bacterial strains were also studied. The results indicate that bacterial strains do not show any resistance to these Amp-AgNps even after exposure up to 15 successive cycles. The biocompatibility of these Amp-AgNps was checked against cell lines by using Keratinocytes cell lines (HaCaT).

Microwave-induced release and degradation of airborne endotoxins from Escherichia coli bioaerosol

Endotoxins are widely distributed toxins in the outer cell-wall membranes of Gram-negative bacteria and other microorganisms. Chronic exposure to endotoxins can induce and exacerbate airway symptoms and diseases. However, the release and degradation of airborne endotoxins from bioaerosol by microwave (MW) irradiation have not yet been reported. This study investigated the distribution and fate of airborne endotoxins during MW irradiation process, as well as the kinetics and thermodynamics of the degradation of airborne endotoxins. Results showed that MW irradiation induced cell lysis, thus considerably increasing the proportion of cells with ruptured membranes. Furthermore, MW irradiation changed the distribution of airborne endotoxins, sharply decreased the concentration of bound endotoxins from 230 EU/m3 to 68 EU/m3, and increased the concentration of free endotoxins from 21 EU/m3 to 122 EU/m3. These results indicated that MW irradiation released endotoxins from cells into the atmosphere. MW irradiation likely degraded endotoxins by exerting thermal effects, which achieved a total endotoxin removal efficiency of as high as 35%. Endotoxin degradation was a first-order reaction and required the activation energy of 26.3 kJ/mol.

Pathogen-Specific Polymeric Antimicrobials with Significant Membrane Disruption and Enhanced Photodynamic Damage To Inhibit Highly Opportunistic Bacteria

Highly pathogenic Gram-negative bacteria and their drug resistance are a severe public health threat with high mortality. Gram-negative bacteria are hard to kill due to the complex cell envelopes with low permeability and extra defense mechanisms. It is challenging to treat them with current strategies, mainly including antibiotics, peptides, polymers, and some hybrid materials, which still face the issue of drug resistance, limited antibacterial selectivity, and severe side effects. Together with precise bacteria targeting, synergistic therapeutic modalities, including physical membrane damage and photodynamic eradication, are promising to combat Gram-negative bacteria. Herein, pathogen-specific polymeric antimicrobials were formulated from amphiphilic block copolymers, poly(butyl methacrylate)- b-poly(2-(dimethylamino) ethyl methacrylate- co-eosin)- b-ubiquicidin, PBMA- b-P(DMAEMA- co-EoS)-UBI, in which pathogen-targeting peptide ubiquicidin (UBI) was tethered in the hydrophilic chain terminal, and Eosin-Y was copolymerized in the hydrophilic block. The micelles could selectively adhere to bacteria instead of mammalian cells, inserting into the bacteria membrane to induce physical membrane damage and out-diffusion of intracellular milieu. Furthermore, significant in situ generation of reactive oxygen species was observed upon light irradiation, achieving further photodynamic eradication. Broad-spectrum bacterial inhibition was demonstrated for the polymeric antimicrobials, especially highly opportunistic Gram-negative bacteria, such as Pseudomona aeruginosa ( P. aeruginosa) based on the synergy of physical destruction and photodynamic therapy, without detectable resistance. In vivo P. aeruginosa-infected knife injury model and burn model both proved good potency of bacteria eradication and promoted wound healing, which was comparable with commercial antibiotics, yet no risk of drug resistance. It is promising to hurdle the infection and resistance suffered from highly opportunistic bacteria.

Synthesis, Biological Evaluation and Docking Studies of Benzoxazoles Derived from Thymoquinone

Thymoquinone (TQ), a natural compound with antimicrobial and antitumor activity, was used as the starting molecule for the preparation of 3-aminothymoquinone (ATQ) from which ten novel benzoxazole derivatives were prepared and characterized by elemental analysis, IR spectroscopy, mass spectrometry and NMR (¹H, ¹³C) spectroscopy in solution. The crystal structure of 4-methyl-2-phenyl-7-isopropyl-1,3-benzoxazole-5-ol (1a) has been determined by X-ray diffraction. All compounds were tested for their antibacterial, antifungal and antitumor activities. TQ and ATQ showed better antibacterial activity against tested Gram-positive and Gram-negative bacterial strains than benzoxazoles. ATQ had the most potent antifungal effect against Candida albicans, Saccharomyces cerevisiae and Aspergillus brasiliensis. Three benzoxazole derivatives and ATQ showed the highest antitumor activities. The most potent was 2-(4-fluorophenyl)-4-methyl-7-isopropyl-1,3-benzoxazole-5-ol (1f). Western blot analyses have shown that this compound inhibited phosphorylation of protein kinase B (Akt) and Insulin-like Growth Factor-1 Receptor (IGF1R β) in HeLa and HepG2 cells. The least toxic compound against normal fibroblast cells, which maintains similar antitumor activities as TQ, was 2-(4-chlorophenyl)-4-methyl-7-isopropyl-1,3-benzoxazole-5-ol (1e). Docking studies indicated that 1e and 1f have significant effects against selected receptors playing important roles in tumour survival.