Post-antibacterial effect of thymol

Protected biofactors and antioxidants reduce the negative consequences of virus and cold challenge by modulating immunometabolism via changes in the interleukin-6 receptor signaling cascade in the liver

Protected biofactors and antioxidants (PBA), and protected biofactors and antioxidants with protected organic acids and essential oils (PBA+POAEO) have been shown to have benefits in stressed or challenged birds. Here, we describe the immunometabolic changes observed in the liver of Ross 308 broilers during feed supplementation and brief physiological stress. These studied additives contain protected essential oils, organic acids, and vitamins which may have protective effects on the liver. Thus, we aimed to determine the signaling changes induced by these supplements and the resultant immunometabolic effects in the liver. All birds received a 2X dose of live bronchitis vaccine at d 0 and a 48-h cold challenge by reducing the temperature from 30 to 32°C, to 20 to 23°C on d 3 to 5. Control birds were fed a standard diet without supplementation. Liver samples were collected to evaluate the effects of these treatments on cytokine gene expression and protein phosphorylation via kinome peptide array. ANOVA was used for statistical analysis of the gene expression data (significance at a p-value of 0.05), and PIIKA2 was used for statistical evaluation and comparative analysis of the kinome peptide array data. At d 15, the kinome peptide array analysis and gene expression data showed stimulation of the interleukin 6 receptor (IL-6R) signal transduction for host protection via heightened immune response while inducing immune modulation and reducing inflammation in both supplement treated groups. Significant changes were observed via IL-6R signaling in the metabolic profiles of both groups compared to control and no significant differences when compared to each other. In the liver, these 2 feed additives induced immunometabolic changes predominantly via the IL-6 receptor family signaling cascade. Differences between the 2 treated groups were predominantly in the metabolic pathways, centered around the mTOR pathway and the proteins AMPK, mTOR and S6K, with a more anabolic phenotype following the addition of essential oils.

Dietary anti-inflammatory and anti-bacterial medicinal plants and its compounds in bovine mastitis associated impact on human life

Bovine mastitis (BM) is the most common bacterial mediated inflammatory disease in the dairy cattle that causes huge economic loss to the dairy industry due to decreased milk quality and quantity. Milk is the essential food in the human diet, and rich in crucial nutrients that helps in lowering the risk of diseases like hypertension, cardiovascular diseases and type 2 diabetes. The main causative agents of the disease include various gram negative, and positive bacteria, along with other risk factors such as udder shape, age, genetic, and environmental factors also contributes much for the disease. Currently, antibiotics, immunotherapy, probiotics, dry cow, and lactation therapy are commonly recommended for BM. However, these treatments can only decrease the rise of new cases but can't eliminate the causative agents, and they also exhibit several limitations. Hence, there is an urgent need of a potential source that can generate a typical and ideal treatment to overcome the limitations and eliminate the pathogens. Among the various sources, medicinal plants and its derived products always play a significant role in drug discovery against several diseases. In addition, they are also known for its low toxicity and minimum resistance features. Therefore, plants and its compounds that possess anti-inflammatory and anti-bacterial properties can serve better in bovine mastitis. In addition, the plants that are serving as a food source and possessing pharmacological properties can act even better in bovine mastitis. Hence, in this evidence-based study, we particularly review the dietary medicinal plants and derived products that are proven for anti-inflammatory and anti-bacterial effects. Moreover, the role of each dietary plant and its compounds along with possible role in the management of bovine mastitis are delineated. In this way, this article serves as a standalone source for the researchers working in this area to help in the management of BM.

Nanoformulated herbal compounds: enhanced antibacterial efficacy of camphor and thymol-loaded nanogels

Herbal components are highly useful assets for the advancement of novel antibacterial drugs. Nanotechnology holds great promise as an approach to enhance the effectiveness and develop the composition of these substances. The study developed nanogels incorporating camphor, thymol, and a combination derived from the initial nanoemulsions with particle sizes of 103, 85, and 135 nm, respectively. The viscosity of nanogels and the successful loading of compounds in them were examined by viscometery and ATR-FTIR studies. The bactericidal properties of the nanogels were examined against four bacterial strains. The nanogel containing camphor and thymol at 1250 µg/mL concentration exhibited complete growth suppression against Pseudomonas aeruginosa and Staphylococcus aureus. The thymol nanogel at 1250 µg/mL and the camphor nanogel at 2500 µg/mL exhibited complete inhibition of growth on Listeria monocytogenes and Escherichia coli, respectively. Both nanogels showed favorable effectiveness as antibacterial agents and could potentially examine a wide range of pathogens and in vivo studies.

The anticancer effects of thymol on HepG2 cell line

There is an increasing incidence of liver cancer, which is a hazard for global health. The present study was designed to evaluate possible cytotoxic, genotoxic, apoptotic, oxidant and antioxidant effects of thymol on hepatocellular carcinoma (HepG2) cell line. The cytotoxic effect of thymol on HepG2 cell line was determined by XTT test. We also used the HUVEC cell line to show whether thymol damages healthy cells. Oxidative stress level was determined with Total Oxidant Status (TOS) and Total Antioxidant Status (TAS) measurement kits. Apoptosis of cells was detected in flow cytometry with Annexin V apoptosis kit. Apoptotic gene expressions were analyzed by real-time PCR. Genotoxicity was determined by comet assay, which measures DNA damage. The thymol IC50 dose was found to be 11 μM on HepG2 cell line. This dose had no lethal effect on the healthy HUVEC cell line. While thymol significantly decreased the TOS level, it increased the TAS level significantly in HepG2 cells compared to control. Thymol significantly induced apoptosis in HepG2 cells (apoptosis rate in control group 1%, in thymol group 21%). Thymol did not alter the gene expressions of bax, bcl-2, and casp3, all of which are associated with apoptosis. Statistically significant change in favor of genotoxicity was observed in tail length measurements. Our results suggest that thymol decreases oxidative stress in HepG2 cell line, but it induces apoptosis and genotoxicity.

Differentiating interactions of antimicrobials with Gram-negative and Gram-positive bacterial cell walls using molecular dynamics simulations

Developing molecular models to capture the complex physicochemical architecture of the bacterial cell wall and to study the interaction with antibacterial molecules is an important aspect of assessing and developing novel antimicrobial molecules. We carried out molecular dynamics simulations using an atomistic model of peptidoglycan to represent the architecture for Gram-positive S. aureus. The model is developed to capture various structural features of the Staphylococcal cell wall, such as the peptide orientation, area per disaccharide, glycan length distribution, cross-linking, and pore size. A comparison of the cell wall density and electrostatic potentials is made with a previously developed cell wall model of Gram-negative bacteria, E. coli, and properties for both single and multilayered structures of the Staphylococcal cell wall are studied. We investigated the interactions of the antimicrobial peptide melittin with peptidoglycan structures. The depth of melittin binding to peptidoglycan is more pronounced in E. coli than in S. aureus, and consequently, melittin has greater contacts with glycan units of E. coli. Contacts of melittin with the amino acids of peptidoglycan are comparable across both the strains, and the D-Ala residues, which are sites for transpeptidation, show enhanced interactions with melittin. A low energetic barrier is observed for translocation of a naturally occurring antimicrobial thymol with the four-layered peptidoglycan model. The molecular model developed for Gram-positive peptidoglycan allows us to compare and contrast the cell wall penetrating properties with Gram-negative strains and assess for the first time binding and translocation of antimicrobial molecules for Gram-positive cell walls.

Enoxacin-based derivatives: antimicrobial and antibiofilm agent: a biology-oriented drug synthesis (BIODS) approach

Background: To find alternative molecules against Klebsiella pneumonia, Proteus mirabilis and methicillin-resistant Staphylococcus aureus, new enoxacin derivatives were synthesized and screened. Methods: All derivatives exhibited promising antibacterial activities as compared to standard enoxacin (2 μg/ml) and standard cefixime (82 μg/ml). Compounds 2, 3 and 5 significantly downregulated the gene expression of biofilm-forming genes. Conclusion: Based on our results, these molecules may serve as potential drug candidates to cure several bacterial infections in the future.

Thymol and carvacrol supplementation in poultry health and performance

BACKGROUND

Thymol and carvacrol as natural essential oils and phenol compounds are components derived from some medicinal plants, such as thyme and oregano species.

OBJECTIVES

The increasing demands in organic and healthy meat and egg consumption in human society have made it necessary to consider alternative natural compounds for the replacement of chemical compounds in poultry production. The chemical compounds can remain in meat and eggs and cause complications in human health. Therefore, these natural compounds can be fed with a higher safety in poultry production with specific effects. In this regard, the role of thymol and carvacrol as natural compounds in the poultry production has been discussed in the review.

METHODS

In this study, by searching for keywords related to thymol and carvacrol in poultry production in Google Scholar database, the articles related to different aspects of the biological effects of these two phytogenes in poultry production were selected and analyzed.

RESULTS

A review of previous studies has shown that thymol and carvacrol possess a wide range of biological activities, including antibacterial, antiviral, antioxidant, anti-inflammatory, modulating of immunity response and regulating of the gut microbial population. Also, in meat type chickens can promote growth and influence feed utilization. The beneficial effect of this compound was evaluated in hepatic toxicity and demonstrated as a hepatoprotective compound in chickens. Furthermore, these compounds can affect the behavior of layers and influence egg composition, eggshell thickness, and the sensory quality of eggs.

CONCLUSION

It seems that with the increasing demand for healthy protein products, these compounds can be used to improve performance as a substitute alternative for chemical compounds in healthy poultry farms.

Voltammetric Determination of Isopropylmethylphenols in Herbal Spices

Thymol and carvacrol—the components of herbal spices—are known for their broad biological activity as antimicrobials and antioxidants. For this reason, it is important to develop new methods for their determination in plant material. A simple, rapid, and sensitive method for determination of total content of these analytes in herbal spices using differential pulse voltammetry (DPV) has been developed. The basis of the research is the oxidation process of isopropylmethylphenols on a platinum microelectrode in glacial acetic acid containing acetonitrile (20%, v/v) and 0.1 mol L⁻¹ sodium perchlorate as the supporting electrolyte. Linear voltammetric responses for thymol and carvacrol were obtained in a wide concentration range from 0.39–1105 and 0.47–640 µg mL⁻¹, with a low detection limit of 0.04 and 0.05 µg mL⁻¹, respectively. The analysis was performed using the multiple standard addition method. The results of the voltammetric determination are in good agreement with the data of the standard chromatographic method. To the best of our knowledge, this is the first presentation of an electrochemical procedure to determine these compounds in these environmental and electrode materials.

Iron Oxide-Silica Core-Shell Nanoparticles Functionalized with Essential Oils for Antimicrobial Therapies

Recent years have witnessed a tremendous interest in the use of essential oils in biomedical applications due to their intrinsic antimicrobial, antioxidant, and anticancer properties. However, their low aqueous solubility and high volatility compromise their maximum potential, thus requiring the development of efficient supports for their delivery. Hence, this manuscript focuses on developing nanostructured systems based on Fe3O4@SiO2 core-shell nanoparticles and three different types of essential oils, i.e., thyme, rosemary, and basil, to overcome these limitations. Specifically, this work represents a comparative study between co-precipitation and microwave-assisted hydrothermal methods for the synthesis of Fe3O4@SiO2 core-shell nanoparticles. All magnetic samples were characterized by X-ray diffraction (XRD), gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry and differential scanning calorimetry (TG-DSC), and vibrating sample magnetometry (VSM) to study the impact of the synthesis method on the nanoparticle formation and properties, in terms of crystallinity, purity, size, morphology, stability, and magnetization. Moreover, the antimicrobial properties of the synthesized nanocomposites were assessed through in vitro tests on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. In this manner, this study demonstrated the efficiency of the core-shell nanostructured systems as potential applications in antimicrobial therapies.

Biomedical Effects of the Phytonutrients Turmeric, Garlic, Cinnamon, Graviola, and Oregano: A Comprehensive Review

Phytonutrients are plant foods that contain many natural bioactive compounds, called phytochemicals, which show specific biological activities. These phytonutrients and their phytochemicals may play an important role in health care maintaining normal organism functions (as preventives) and fighting against diseases (as therapeutics). Phytonutrients’ components are the primary metabolites (i.e., proteins, carbohydrates, and lipids) and phytochemicals or secondary metabolites (i.e., phenolics, alkaloids, organosulfides, and terpenes). For years, several phytonutrients and their phytochemicals have demonstrated specific pharmacological and therapeutic effects in human health such as anticancer, antioxidant, antiviral, anti-inflammatory, antibacterial, antifungal, and immune response. This review summarizes the effects of the most studied or the most popular phytonutrients (i.e., turmeric, garlic, cinnamon, graviola, and oregano) and any reported contraindications. This article also presents the calculated physicochemical properties of the main phytochemicals in the selected phytonutrients using Lipinski’s, Veber’s, and Ghose’s rules. Based on our revisions for this article, all these phytonutrients have consistently shown great potential as preventives and therapeutics on many diseases in vitro, in vivo, and clinical studies.

Assessing Barriers for Antimicrobial Penetration in Complex Asymmetric Bacterial Membranes: A Case Study with Thymol

The bacterial cell envelope is a complex multilayered structure evolved to protect bacteria in hostile environments. An understanding of the molecular basis for the interaction and transport of antibacterial therapeutics with the bacterial cell envelope will enable the development of drug molecules to combat bacterial infections and suppress the emergence of drug-resistant strains. Here we report the successful creation of an in vitro supported lipid bilayer (SLB) platform of the outer membrane (OM) of E. coli, an archetypical Gram-negative bacterium, containing the full smooth lipopolysaccharide (S-LPS) architecture of the membrane. Using this platform, we performed fluorescence correlation spectroscopy (FCS) in combination with molecular dynamics (MD) simulations to measure lipid diffusivities and provide molecular insights into the transport of natural antimicrobial agent thymol. Lipid diffusivities measured on symmetric supported lipid bilayers made up of inner membrane lipids show a distinct increase in the presence of thymol as also corroborated by MD simulations. However, lipid diffusivities in the asymmetric OM consisting of only S-LPS are invariant upon exposure to thymol. Increasing the phospholipid content in the LPS-containing outer leaflet improved the penetration toward thymol as reflected in slightly higher relative diffusivity changes in the inner leaflet when compared with the outer leaflet. Free-energy computations reveal the presence of a barrier (∼6 kT) only in the core-saccharide region of the OM for the translocation of thymol while the external O-antigen part is easily traversed. In contrast, thymol spontaneously inserts into the inner membrane. In addition to providing leaflet-resolved penetration barriers in bacterial membranes, we also assess the ability of small molecules to penetrate various membrane components. With rising bacterial resistance, our study opens up the possibility of screening potential antimicrobial drug candidates using these realistic model platforms for Gram-negative bacteria.

Antimicrobial Potential of Fungal Endophytes from Moringa oleifera

The present study was aimed to isolate the endophytic fungi having antimicrobial potential from Moringa oleifera. Out of the active isolates, the endophytic fungal isolate DSE 17 obtained from the bark of the plant was selected for further studies and identified as Aspergillus fumigatus. The classical method for optimization strategy revealed inoculum size of four discs in Czapek dox's medium at a temperature of 25 °C and pH 7 with the incubation period of 6 days to be the best. Sucrose as carbon source (1%) and sodium nitrate as nitrogen source (0.2%) were found to be the best for antimicrobial activity. Response surface methodology was effective in optimizing the selected medium components in Plackett-Burman design, i.e. magnesium sulphate, dipotassium phosphate and sodium nitrate, which resulted in increase in antimicrobial activity by 1.7-fold. Chloroform was found to be the best extractant amongst different solvents. The minimum inhibitory concentration (MIC) values of the chloroformic extract ranged from 0.05 to 0.5 mg/ml, and the viable cell count studies revealed it to be bactericidal in its nature. The post-antibiotic effect (PAE) of the chloroformic extracts ranged from 2 to 20 h. Ames mutagenicity testing and MTT assay revealed the crude extract neither cytotoxic nor mutagenic, thus showing it to be biosafe. Thus, the study suggests that endophytes from this miracle plant could be potential source for the production of broad-spectrum antimicrobial compound/s.

Mode of action and synergistic effect of valinomycin and cereulide with amphotericin B against Candida albicans and Cryptococcus albidus

Both valinomycin and cereulide are cyclic depsipeptides and are known K⁺ ion-selective ionophores. Valinomycin and cereulide feature low minimum inhibitory concentration (MIC) values against Candida albicans and Cryptococcus albidus. This study aims at investigating the mode of action and verifying the efficacy of valinomycin or cereulide alone and in combination with amphotericin B (AmB) in vitro against both microorganisms. Based on the results from membrane permeability and fluidity assays for detection of plasma membrane permeabilization and membrane dynamics, the present study demonstrated that valinomycin and cereulide exhibit antifungal activity against C. albicans and C. albidus by interrupting membrane-associated function. The mode of action of both valinomycin and cereulide are similar with that of AmB. Time-kill kinetics assay showed that valinomycin and cereulide exhibit fungistatic activity, whereas AmB features fungicidal activity. Additionally, the combination of compounds between each cyclic peptide and AmB reached maximal fungicidal activity more rapidly than AmB alone. This result corresponded with findings of scanning electron microscopy, fractional inhibitory concentration index and minimum fungicidal concentration (MFC)/MIC ratio, indicating that combinations of the drugs show synergistic effects for inhibiting the growth of these fungal strains. Sorbitol and ergosterol assays showed that both cyclic peptides affected cell wall and membrane components due to increases in MIC value, as observed in medium with sorbitol and ergosterol. Valinomycin and cereulide may promote permeability of fungal cell wall and cell membrane when used in combination with AmB.

Effect of myrrh and thyme on Trichinella spiralis enteral and parenteral phases with inducible nitric oxide expression in mice

Trichinellosis is a serious disease with no satisfactory treatment. We aimed to assess the effect of myrrh (Commiphora molmol) and, for the first time, thyme (Thymus vulgaris L.) against enteral and encysted (parenteral) phases of Trichinella spiralis in mice compared with albendazole, and detect their effect on inducible nitric oxide synthase (iNOS) expression. Oral administration of 500 mg/kg of myrrh and thyme led to adult reduction (90.9%, 79.4%), while 1,000 mg/kg led to larvae reduction (79.6%, 71.3%), respectively. Administration of 50 mg/kg of albendazole resulted in adult and larvae reduction (94.2%, 90.9%). Positive immunostaining of inflammatory cells infiltrating intestinal mucosa and submucosa of all treated groups was detected. Myrrh-treated mice showed the highest iNOS expression followed by albendazole, then thyme. On the other hand, both myrrh and thyme-treated groups showed stronger iNOS expression of inflammatory cells infiltrating and surrounding encapsulated T. spiralis larvae than albendazole treated group. In conclusion, myrrh and thyme extracts are highly effective against both phases of T. spiralis and showed strong iNOS expressions, especially myrrh which could be a promising alternative drug. This experiment provides a basis for further exploration of this plant by isolation and retesting the active principles of both extracts against different stages of T. spiralis.

Synergistic bactericidal activity between hyperosmotic stress and membrane-disrupting nanoemulsions

There is a clear clinical need for alternative types of non-antibiotic biocides due to the rising global health concern of microbial drug resistance. In this work, a novel antibacterial concept was delineated that utilized hyperosmotic stress (H) in concert with membrane-disrupting nanoemulsions (NEs). The antibacterial effects of either H or a NE, as well as in combination (H+NE), were assessed in vitro using an Escherichia coli model. It was found that exposure to H or NE alone produced dose-dependent bacteriostatic and bactericidal effects, respectively. However, the bactericidal action of NE was significantly amplified in the presence of H. Outcomes following H+NE exposure included rapid efflux of K(+) and nucleic acids, increased membrane permeability and a reduction in both intracellular ATP and cell viability. Further inspection of morphology by electron microscopy highlighted cell shrinkage, membrane dissolution and bacteriolysis. Pathogen inactivation occurred immediately upon contact with H+NE. The effects of H, NE and H+NE against Enterococcus faecalis, Staphylococcus aureus and meticillin-resistant S. aureus isolates were also examined. Similar to the Escherichia coli model, H+NE showed antibacterial synergism in these organisms when classified by the Chou-Talalay combination index for two-agent interactions. This synergistic interaction suggests that the H+NE platform may potentially serve as a new paradigm in disinfectants, antiseptics and antibacterial wound dressings. The H+NE mechanism of action was termed osmopermeation, as a descriptor for the underlying inactivation process.

Evaluation of the antimicrobial potential of two flavonoids isolated from limnophila plants

The antimicrobial potential of two bioflavonoids, i.e., 5,7-dihydroxy-4',6,8-trimethoxyflavone (1) and 5,6-dihydroxy-4',7,8-trimethoxyflavone (2), isolated from Limnophila heterophylla Benth. and L. indica (Linn.) Druce (Scrophulariaceae), respectively, were evaluated against the microbial strains Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Alternaria solani, and Candida albicans. Compounds 1 and 2 exhibited moderate but broad antimicrobial activities against both Gram-positive and Gram-negative bacteria and also against the fungal pathogens. Moreover, the mechanism of action of 1 and 2 on the cellular functions or structures of some of the microorganisms was studied. Compound 1 showed a bactericidal effect against E. coli and S. aureus (MICs of 200 and 250 μg/ml, resp.), while compound 2 was found to effectively kill B. subtilis by cell lysis. The growth of A. solani and C. albicans was inhibited by compounds 1 and 2, respectively. The effects of the flavonoids on the cellular structures and the carbohydrate metabolic pathways were studied by scanning electron microscopy (SEM) of the treated cells and by assessing the specific activity of key enzymes of the pathways, respectively. At sublethal doses, they enhanced the activity of gluconeogenic fructose bisphosphatase, but decreased the activity of phosphofructokinase and isocitrate dehydrogenase, the key enzymes of the EmbdenMeyerhofParnas pathway and the tricarboxylic acid cycle, respectively.

Phytochemical analysis and in vitro antimicrobial and free-radical-scavenging activities of the essential oils from Euryops arabicus and Laggera decurrens

The essential oils of the aerial part of two Asteraceae species, namely Euryops arabicus Steud. and Laggera decurrens (Vahl.) Hepper and Wood, were studied by GC and GC/MS. In parallel the antimicrobial and antioxidant activities were evaluated. The investigation led to the identification of 48 and 44 compounds for both plants, respectively. The essential oil of E. arabicus was rich in oxygenated sesquiterpenes (39.9%). The oil also contained a high content of sesquiterpene hydrocarbons (24.1%). Compounds such as caryophyllene oxide (8.6%), T-cadinol (7.0%), spathulenol (5.2%), (E)-β-caryophyllene (6.0%) and 2-epi-(E)-β-caryophyllene (6.0%) were the main constituents of the oil. Oxygenated monoterpenes also predominated in L. decurrens (46.3%). The thymoquinone-derivative, 3-methoxy-2-methyl-5-(1-methylethyl)-2,5-cyclohexadiene-1,4-dione (28.1%), thymol (5.7%) and eudesma-11-en-4a-ol (7.0%) were the most abundant constituents. Both essential oils showed antimicrobial activity with MIC-values between 0.13–5.25 mg/mL. Furthermore, only the essential oil of L. decurrens exhibited a strong antioxidant activity (91%) at 500 µg/mL.