A review on oxidant and antioxidant effects of antibacterial agents: impacts on bacterial cell death and division and therapeutic effects or adverse reactions in humans

Reactive oxygen species (ROS) are produced in the mitochondrial respiratory pathway and cellular metabolism. They are responsible for creating oxidative stress and lipid peroxidation. In living organisms, there is a balance between oxidative stress and the antioxidant system, but some factors such as medicines disturb the balance and cause many problems. These effects can impact bacterial death and division and also in humans can induce therapeutic or adverse reactions. Web of Science and Pubmed databases were used for searching. This review focuses on the oxidant and antioxidant effects of different classes of antibacterial agents and the mechanisms of oxidative stress. Some of these agents have beneficial effects on killing bacteria due to their antioxidant or oxidant effects. However, some of their side effects may be due to their oxidative effects. Based on the results of this review, minocycline is an antioxidant, but aminoglycosides, chloramphenicol, glycopeptides, antituberculosis drugs, fluoroquinolones, and sulfamethoxazole agents have oxidant effects. Furthermore, cephalosporins, penicillins, metronidazole, and macrolides have both oxidant and antioxidant effects in different studies. It is concluded that some antibacterial agents have oxidant and other antioxidant effects. These activities may affect their therapeutic effects or side effects. Some antioxidants can prevent the adverse effects of antibacterial agents. Clarifying the exact oxidant and antioxidant effects of some antimicrobial agents needs more research projects.

The potential therapeutic impact of a topical bacteriophage preparation in treating Pseudomonas aeruginosa-infected burn wounds in mice

Aim

This study compared a topical formulation containing lytic phages with a routine antibiotic in the murine model of burn/Pseudomonas aeruginosa infected wound healing.

Methods & Materials

Isolated and purified lytic bacteriophages from hospital sewage were added to the polyethylene glycol (PEG) based ointment. A second-degree burned wound on the back of twenty-four adult female mice was created. The wounds were infected subcutaneously with 100 μL of 1 × 102-3 CFU/mL P. aeruginosa. After 24 h, mice were randomly assigned to one of four groups: mice received a standard antibiotic (antibiotic-treated group), mice received an ointment without bacteriophage (PEG-based group), mice received a PEG-ointment with bacteriophage (bacteriophage-treated group), or mice received no treatment (untreated-control group). Every two days, the contraction of burned wounds, physical activity, and rectal body temperature were recorded. On day 10, mice were sacrificed, and the wounds were cut off and evaluated histopathologically.

Results

In ointments containing PEG, bacteriophages were active and stable. The mice receiving bacteriophage and PEG-based ointment had substantially different wound contraction in primary wound healing (P = 0.001). When compared to the control group, the bacteriophage-treated group showed significant variations in wound contraction (P = 0.001). The wound contraction changed significantly between the antibiotic and PEG-based groups (P = 0.002). In all groups, physical activity in mice improved over time, with significant differences (P = 0.001). When the 8th day was compared to the days 2, 4, and 6, significant changes were found (P = 0.001, P = 0.02, and P = 0.02, respectively). Both the positive control and bacteriophage-treated groups showed perfect wound healing histopathologically. However, no significant variations in microscopic histopathological criteria were found between the groups.

Conclusion

Formulated phage ointment could be a promising approach for treating infected burn wounds infected by P. aeruginosa in mice with no allergic reactions.

Anti-quorum sensing and antibiofilm activity of coumarin derivatives against Pseudomonas aeruginosa PAO1: Insights from in vitro and in silico studies

Objectives

Biofilm-associated infections are challenging to manage or treat since the biofilm matrix is impenetrable to most antibiotics. Therefore, the best approach to deal with biofilm infections is to interrupt the construction during the initial levels. Biofilm formation has been regulated through the quorum sensing (QS) network, making it an attractive target for any antibacterial therapy.

Materials and Methods

Here, some coumarin members, including umbelliprenin, 4-farnesyloxycoumarin, gummosin, samarcandin, farnesifrol A, B, C, and auraptan, have been assessed as QS inhibitors in silico and in vitro. Their potential inhibitory effects on biofilm formation and virulence factor production of Pseudomonas aeruginosa PAO1 were evaluated.

Results

First, the interaction of these compounds was investigated against one of the major transcriptional regulator proteins, PqsR, using molecular docking and structural analysis methodology. After that, in vitro evaluations indicated that 4-farnesyloxycoumarin and farnesifrol B showed considerable reduction in biofilm formation (62% and 56%, respectively), virulence factor production, and synergistic effects with tobramycin. Moreover, 4-farnesyloxycoumarin significantly (99.5%) reduced PqsR gene expression.

Conclusion

The biofilm formation test, virulence factors production assays, gene expression analysis, and molecular dynamic simulations data demonstrated that coumarin derivatives are a potential anti-QS family through PqsR inhibition.

A randomized, double-blind placebo-controlled add-on trial to assess the efficacy, safety, and anti-atherogenic effect of spirulina platensis in patients with inadequately controlled type 2 diabetes mellitus

The efficacy of spirulina platensis (S. platensis) as an add-on therapy to metformin and its effect on atherogenic keys in patients with uncontrolled Type 2 Diabetes Mellitus (T2DM) was evaluated. Sixty patients were randomly assigned to S. platensis (2 g/day) or placebo group for three months while continuing metformin as their usual treatment. The efficacy of S. platensis was determined using the pre- and post-intervention HbA1c levels (primary outcome) as well as tracking FBS and lipid profiles levels (TC, LDL-C, TG, and HDL-C) as secondary outcomes at the different treatment time points (0,30,60,90 days). During the three-month intervention period, supplementation with S. platensis resulted in a significant lowering of HbA1c (↓1.43, p < 0.001) and FBS (↓ 24.94 mg/dL, p < 001) levels. Mean TG in the intervention group was found to be significantly lower in the intervention group than in controls (p < 0.001). Total cholesterol (TC) and its fraction, LDL-C, exhibited a fall (↓41.36 mg/dL and ↓38.4 mg/dL, respectively; p < 0.001) coupled with a marginal increase in the level of HDL-C (↑3 mg/dL; p < 0.001). Add-on therapy with S. platensis was superior to metformin regarding long-term glucose regulation and controlling blood glucose levels of subjects with T2DM. Also, as a functional supplement, S. platensis has a beneficial effect on atherogenic keys (TG and HDL-C) with no adverse events.

Recent Progresses in Analytical Perspectives of Degradation Studies and Impurity Profiling in Pharmaceutical Developments: An Updated Review

Forced degradation studies have been used to simplify analytical methodology development and achieve a deeper knowledge about the inherent stability of active pharmaceutical ingredients (API) and drug products. This provides insight into degradation species and pathways. Identification of impurities in pharmaceutical products is closely related to the selection of the most appropriate analytical methods like HPLC-UV, LC-MS/MS, LC-NMR, GC-MS, and capillary electrophoresis. Herein, recent trends in analytical perspectives during 2018-April 14, 2021, are discussed based on forced and impurity degradation profiling of pharmaceuticals. Literature review showed that several methods have been used for experimental design and analysis conditions such as matrix type, column type, mobile phase, elution modes, detection wavelengths, and therapeutic category. Thus, since these factors influence the separation and identification of the impurities and degradation products, we attempted to perform a statistical analysis for the developed methods according to the abovementioned factors.

Dual Antibiotic and Diffusible Signal Factor Combination Nanoliposomes for Combating Staphylococcus epidermidis Biofilm

Purpose: Microbial biofilms are one of the main causes of persistent human infections. Encapsulation of an antibiotic and a biofilm dispersal agent within a nano-carrier has been recognized as a novel approach to combat the problem of biofilm-related infections. Here, we develop the nanoliposomal formulation for delivery of vancomycin in combination with cis-2- decenoic acid (C2DA), to Staphylococcus epidermidis biofilm. The effects of the formulations were studied at two stages: biofilm growth inhabitation and biofilm eradication.

Methods: Liposomal formulations were prepared by the solvent evaporation dehydration-rehydration method and were evaluated for size, zeta potential, and encapsulation efficacy. The ability of different agents in free and encapsulated forms were assessed to evaluate the anti-biofilm activities.

Results: Vancomycin and C2DA were successfully co-encapsulated in the same nanoliposome (liposomal combination). The zeta potential values of the liposomal formulations of vancomycin, C2DA, and the liposomal combination were 37.2, 40.2, 51.5 mV, and the mean sizes of these liposomal formulations were 167.8±1.5, 215.5±8.8, 235.5±0.01, respectively. Encapsulation efficacy of C2DA was 65% and about 40% for vancomycin. The results indicated that liposomal combination exerted strong anti-biofilm activities, slightly exceeding those observed by the free form of a combination of vancomycin and C2DA, but higher than either agent used alone in their free forms. The anti-biofilm activity of formulations followed concentration and time-dependent manner.

Conclusion: The combination of vancomycin and C2DA could inhibit biofilm formation. Employing the liposomal combination is a considerable method to remove bacterial biofilm.

Implantation of stem cells on synthetic or biological scaffolds: an overview of bone regeneration

Humans are exposed to a wide range of bone tissue injuries. In severe cases, bone damages could be only treated with transplantation of autologous or allogeneic grafting.In recent years, tissue engineering has become a promising strategy for repairing damaged organs and tissues, providing a great opportunity to cure several diseases. Bone tissue engineering consists of three components: scaffold, cells, and growth factors. Current bone tissue engineering strategies combine the use of stem cells with biologically active materials and gene therapy to mimic the natural microenvironment of bone. The combination of the scaffold with growth factors and extracellular matrix protein molecules can promote cell attachment, proliferation, and induce osteogenesis, which could provide signals for cell migration to begin the healing process during repair and bone formation.This article reviews the principles of bone regeneration and the most current developments of bone tissue engineering related to bone growth factors, the biologically active materials, such as bacterial cellulose, and stem cells.

Anti-quorum sensing potential of ketoprofen and its derivatives against Pseudomonas aeruginosa: insights to in silico and in vitro studies

Antibiotics are usually used for the treatment of bacterial infections, but multidrug-resistant strains are a phenomenon that has been growing at an increasing rate worldwide. Thus, there is an increasing need for novel strategies for combatting infectious diseases. Many pathogenic bacteria apply quorum sensing (QS) to regulate their pathogenicity and virulence factors production. This circuit makes the QS system an attractive target for antibacterial therapy. In the present study, an important member of non-steroidal anti-inflammatory drugs (NSAIDs), by reducing the biofilm and producing QS-regulated virulence factors, ketoprofen and its synthetic derivatives were screened against the Pseudomonas aeruginosa PAO1. All compounds showed anti-biofilm activity (16-79%) and most of them presented anti-virulence activity. In the co-treatment of ketoprofen, G20, G21, or G77 with tobramycin, biofilm is significantly reduced (potentiated to > 50%) in the number of cells protected inside the impermeable matrix. The in silico studies in addition to the similarities between the chemical structures of PqsR natural ligands and ketoprofen derivatives reinforce the possibility that the mechanism of action is through PqsR inhibition. Based on the results, the anti-pathogenic effect was more appreciable in ketoprofen, G77, and G20.

pH-sensitive soluble soybean polysaccharide/SiO2 incorporated with curcumin for intelligent packaging applications

In the present work, the effect of various concentrations of SiO₂ nanoparticles (5, 10, and 15%) on physicochemical and antimicrobial properties of soluble soybean polysaccharide (SSPS)‐based film was investigated. Then, the migration of SiO₂ nanoparticles to ethanol as a food simulant was evaluated. Subsequently, curcumin was added to the nanocomposite formulation to sense the pH changes. Finally, the cytotoxicity of the developed packaging system was investigated. With increasing nanoparticle concentration, the film thickness, water solubility, and water vapor permeability decreased and mechanical performance of the films improved. SSPS/SiO₂ nanocomposite did not show antibacterial activity. SEM analysis showed that SiO₂ nanoparticles are uniformly distributed in the SSPS matrix; however, some outstanding spots can be observed in the matrix. A very homogeneous surface was observed for neat SSPS film with R_a and R_q values of 3.48 and 4.26, respectively. With the incorporation of SiO₂ (15%) into SSPS film, R_a and R_q values increased to 5.67 and 5.98, respectively. Small amount of SiO₂ nanoparticles was released in food simulant. The nanocomposite incorporated with curcumin showed good physical properties and antibacterial activity. A strong positive correlation was observed between TVBN content of shrimp and a* values of the films during storage time (Pearson's correlation = 0.985).

Evaluation of wound healing efficiency of vancomycin-loaded electrospun chitosan/poly ethylene oxide nanofibers in full thickness wound model of rat

Electrospun hybrid nanofibers have been extensively regarded as drug carriers. This study tries to introduce a nano fibrous wound dressing as a new strategy for a topical drug-delivery system. The vancomycin (VCM)-loaded hybrid chitosan/poly ethylene oxide (CH/PEO) nanofibers were fabricated by the blend-electrospinning process. Morphological, mechanical, chemical, and biological properties of nanofibers were examined by SEM, FTIR, release profile study, tensile assay, Alamar Blue cytotoxicity evaluation, and antibacterial activity assay. In vivo wound healing activity of hybrid CH/PEO/VCM nanofibers was evaluated in full-thickness skin wounds of rats. The hybrid CH/PEO/VCM nanofibers were successfully fabricated in a nanometer. The CH/PEO/VCM 2.5% had higher Young's Modulus, better tensile strength, smaller fiber diameter with sustained-release profiles compared to CH/PEO/VCM 5%. All nanofibers did not show any significant cytotoxicity (P < 0.05) on the normal fibroblast cells. Also, VCM-load hybrid CH/PEO nanofibers successfully inhibited bacterial growth. The wound area in the rats treated with CH/PEO/VCM 2.5% was less than CH/PEO/VCM 5% treated group. According to histological evaluation, the CH/PEO/VCM 2.5% group showed the fastest wound healing than other treatment groups. Results of this study proposed that CH/PEO/VCM nanofibers could promote the wound healing process by reducing the side effects of VCM as a topical antimicrobial agent.

Deep insights into urinary tract infections and effective natural remedies

Background

Urinary tract infection (UTI) is a common occurrence in females, during pregnancy, and in peri- and postmenopausal women. UTIs are associated with significant morbidity and mortality, and they affect the quality of life of the affected patients. Antibiotic therapy is an effective approach and reduces the duration of symptoms. Development of resistance, adverse effects of antibiotics, and other associated problems lead to establishing the research framework to find out the alternative approaches in controlling UTIs. Natural approaches have been extensively used for the management of various diseases to improve symptoms and also improve general health.

Main body

Different databases were employed to identify studies reporting on natural options including herbal medicines, vitamins, trace elementals, sugars, and probiotics without time limitations.

Conclusion

Herbal medicines can be effective at the first sign of the infection and also for short-term prophylaxis. Using vitamins, trace elementals, and/or sugars is an effective approach in preventing UTIs, and a combination of them with other antibacterial agents shows positive results. Probiotics have great potential for the threat of antibiotic over-usage and the prevalence of antibiotic-resistant microorganisms. This study may be of use in developing the efficient formulation of treatment of UTI.

Antioxidant, antimicrobial, and cytotoxic activities of extracts from the seed and pulp of Jujube (Ziziphus jujuba) grown in Iran

The aim of the present study was to investigate the biological activities of the ultrasound‐assisted extracts obtained from pulp and seed of jujube (Ziziphus jujuba) fruits. To reach this purpose, total phenolic content (TPC), total flavonoid content (TFC), total pro‐anthocyanin, DPPH radical scavenging activity, rancimat test, as well as antimicrobial activity and cytotoxicity test of both jujube pulp and seed extracts were evaluated. Total phenolic content (TPC), total flavonoid content (TFC), and total pro‐anthocyanin in pulp extract were higher than those obtained from seed extract. In addition, DPPH radical scavenging activity of pulp extract (IC₅₀ = 53.97 µg/ml) was higher than that of seed extract (IC₅₀ = 88.68 µg/ml). Furthermore, the highest antimicrobial activity was observed against Escherichia coli and Staphylococcus aureus (MIC = 20 mg/ml) for both seed and pulp extracts. In vitro cytotoxicity evaluation on seven cell lines revealed that pulp and seed extracts of jujube had no cytotoxic activity. The present results suggested the promising antioxidant properties of jujube, which can be used in the fabrication of functional bioactive ingredients for different purposes.

Topical green tea formulation with anti-hemorrhagic and antibacterial effects

Objective(s):

Potentially preventable death from uncontrolled hemorrhage clearly indicates the importance of simple, fast and efficient ways to achieving hemostasis. The aim of this study was to develop a topical formulation of green tea extract for reducing bleeding that can be helpful in hemorrhage control.

Materials and Methods:

Hydroalcoholic extract of green tea was isolated from Camellia sinensis and formulated in polyvinyl alcohol (PVA) to achieve two concentrations of 2% and 4% v/v. Folin-Ciocalteau assay was used to determine the total amount of tannins in extract. Rheological behavior of solutions was investigated by measuring viscosity at shear rates of 0–200 sec⁻¹. Quantitative and qualitative microbial limit tests and minimum inhibitory concentration (MIC) assay were done. The effect of formulations on bleeding time was evaluated in an animal model.

Results:

The total amount of tannin in green tea extract was 3.8% w/w and addition of green tea significantly increased the viscosity of PVA. The results of MIC assay showed that PVA could not inhibit the growth of bacteria, while, 716 µg/ml of green tea and 2860 µg/ml of green tea/PVA 4% inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa. In an animal study both 2% and 4% formulations were able to stop hemorrhage approximately at an equal time compared with tranexamic acid (TXA) 50 mg/ml as a control and the lowest bleeding time was 6.4±0.51 sec for green tea/PVA 4%.

Conclusion:

Based on our results, the topical formulation of green tea extract in PVA has a great potential for anti-hemorrhage applications.

T-Box20 inhibits osteogenic differentiation in adipose-derived human mesenchymal stem cells: the role of T-Box20 on osteogenesis

Background

Skeletal development and its cellular function are regulated by various transcription factors. The T-box (Tbx) family of transcription factors have critical roles in cellular differentiation as well as heart and limbs organogenesis. These factors possess activator and/or repressor domains to modify the expression of target genes. Despite the obvious effects of Tbx20 on heart development, its impact on bone development is still unknown.

Methods

To investigate the consequence by forced Tbx20 expression in the osteogenic differentiation of human mesenchymal stem cells derived from adipose tissue (Ad-MSCs), these cells were transduced with a bicistronic lentiviral vector encoding Tbx20 and an enhanced green fluorescent protein.

Results

Tbx20 gene delivery system suppressed the osteogenic differentiation of Ad-MSCs, as indicated by reduction in alkaline phosphatase activity and Alizarin Red S staining. Consistently, reverse transcription-polymerase chain reaction analyses showed that Tbx20 gain-of-function reduced the expression levels of osteoblast marker genes in osteo-inductive Ad-MSCs cultures. Accordingly, Tbx20 negatively affected osteogenesis through modulating expression of key factors involved in this process.

Conclusion

The present study suggests that Tbx20 could inhibit osteogenic differentiation in adipose-derived human mesenchymal stem cells.

Review on plant antimicrobials: a mechanistic viewpoint

Microbial resistance to classical antibiotics and its rapid progression have raised serious concern in the treatment of infectious diseases. Recently, many studies have been directed towards finding promising solutions to overcome these problems. Phytochemicals have exerted potential antibacterial activities against sensitive and resistant pathogens via different mechanisms of action. In this review, we have summarized the main antibiotic resistance mechanisms of bacteria and also discussed how phytochemicals belonging to different chemical classes could reverse the antibiotic resistance. Next to containing direct antimicrobial activities, some of them have exerted in vitro synergistic effects when being combined with conventional antibiotics. Considering these facts, it could be stated that phytochemicals represent a valuable source of bioactive compounds with potent antimicrobial activities.

Overexpression of MicroRNA-148b-3p stimulates osteogenesis of human bone marrow-derived mesenchymal stem cells: the role of MicroRNA-148b-3p in osteogenesis

Background

Mesenchymal stem cells (MSCs) are attractive choices in regenerative medicine and can be genetically modified to obtain better results in therapeutics. Bone development and metabolism are controlled by various factors including microRNAs (miRs) interference, which are small non-coding endogenous RNAs.

Methods

In the current study, the effects of forced miR-148b expression was evaluated on osteogenic activity. Human bone marrow-derived mesenchymal stem cells (BM-MSCs) were transduced with bicistronic lentiviral vector encoding hsa-miR-148b-3p or -5p and the enhanced green fluorescent protein. Fourteen days post-transduction, immunostaining as well as Western blotting were used to analyze osteogenesis.

Results

Overexpression of miR-148b-3p increased the osteogenic differentiation of human BM-MSCs as demonstrated by anenhancement of mineralized nodular formation and an increase in the levels of osteoblastic differentiation biomarkers, alkaline phosphatase and collagen type I.

Conclusions

Since lentivirally overexpressed miR-148b-3p increased osteogenic differentiation capability of BM-MSCs, this miR could be applied as a therapeutic modulator to optimize bone function.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0854-3) contains supplementary material, which is available to authorized users.

Preparation and Characterization of a Dry Powder Inhaler Composed of PLGA Large Porous Particles Encapsulating Gentamicin Sulfate

Purpose: Direct delivery of aminoglycosides to the lungs was under extensive evaluations during the last decades. Because of large particle size, low density and porous structure, large porous particles (LPPs) are versatile carriers for this purpose. In this study, poly (lactic-co-glycolic acid) (PLGA) LPPs encapsulating gentamicin sulfate were prepared and in vitro characteristics of their freeze-dried powder as a dry powder inhaler (DPI) were evaluated.

Methods: To prepare PLGA LPPs, a double emulsification-solvent evaporation method was optimized and gentamicin sulfate was post-loaded in the LPPs. in vitro characteristics including morphological features, thermal behavior, aerodynamic profile and cumulative drug release were evaluated by the scanning electron microscope (SEM), differential scanning calorimetry (DSC), next-generation cascade impactor (NGI) and Franz diffusion cell respectively.

Results: The obtained results revealed that the preparation method was capable to produce spherical large homogenous highly porous particles. 94% of gentamicin sulfate released from LPPs up to 30 minutes. Mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF) were 4.9 µm and 39% respectively.

Conclusion: In this study, dry powder formulation composed of PLGA LPPs encapsulating gentamicin sulfate showed a promising in vitro behavior as a pulmonary delivery carrier. Improvements on the aerodynamic behavior and in vivo evaluations recommended for further developments.

Effects of Omeprazole and Caffeine Alone and in Combination with Gentamicin and Ciprofloxacin Against Antibiotic Resistant Staphylococcus Aureus and Escherichia Coli Strains

Objective

Antibiotic resistance is a global health problem and threatens health of societies. These problems have led to a search for alternative approaches such as combination therapy. The aim of the present study was to investigate the effect of caffeine and omeprazole in combination with gentamicin or ciprofloxacin against standard and clinically resistant isolates of Staphylococcus aureus and Escherichia coli.

Methods

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interaction of non- antibiotic drugs with gentamicin and ciprofloxacin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI). Verapamil as efflux pump inhibitor was used to evaluate the possible mechanism of bacterial resistance to antibiotics.

Results

The MIC and MBC values of gentamicin against bacterial strains were in the range of 20- 80 μg/ml and 40-200 μg/ml, respectively. Caffeine and omeprazole had no intrinsic inhibitory activity against tested microorganisms. However, upon combination of caffeine with antibiotics, the synergistic effects were observed. Verapamil was able to reduce the MIC values of gentamicin (4 folds) only in some bacterial strains.

Conclusion

These findings indicated that caffeine was effective in removing bacterial infection caused by S. aureus and E. coli. The relevant mechanisms of antibiotic resistance were not related to the drug efflux.

A review and new insights to antimicrobial action of local anesthetics

Local anesthetics (LAs) are medications which can provide analgesia in distinct body regions through the blockade of voltage-gated sodium channels. Besides pain management, the supplemental role of LAs as antimicrobial agents has been documented in several studies. Different databases including PubMed, Scopus, and Web of Science with the name of different local anesthetics and related names for antimicrobial keywords were searched without time limitation. This review summarized different in vitro and in vivo studies regarding antimicrobial effects of different LAs with focuses on antimicrobial applications of most studied LAs, interaction with different agents which combined with LAs, and mechanisms of action and structural dependence of LAs antibacterial effects. Among different LAs, lidocaine is the most studied preparation. Reduction of the incidence of endophthalmitis after intravitreal injection, prophylaxis for surgical wound infections, prevention of the incidence of catheter-associated infections, oral biofilm reduction on the buccal mucosa, and prevention against bacteria that produced nosocomial infection are some examples of lidocaine antimicrobial application. Studies showed that different factors including structure, concentration, duration of exposure, type of microorganism tested, and temperature affect the degree of LA antimicrobial activity. In addition, various agents such as antibiotics, preservatives, opioids, epinephrine, and propofol can combine with LAs and affect their antimicrobial properties through synergistic or antagonistic action. Due to antibacterial activities, LAs could be applied in a clinic for prophylaxis of surgical site infection. In the application of LAs prior to diagnostic procedures caution should be needed; otherwise, when culturing the specimen, they could lead to false negative results.

Does Biosynthetic Silver Nanoparticles Are More Stable With Lower Toxicity than Their Synthetic Counterparts?

Control of size and shape is a challenge in nanoparticle synthesis. Synthetic and biosynthetic (both extracellular and intracellular) methods are used to prepare silver nanoparticle (SNP). In this study, the behavior of three strains of Staphylococcus aureus (S. aureus) was investigated in the presence of silver nitrate intra- and extracellularly. S. aureus strains biosynthesized SNPs intracellularly, while in the method of the extracellular biosynthesis, none of the strains could produce the SNP under different conditions (dark, bright light, and the presence of nitrate ion). Intracellular SNPs were purified. The results of this study and previous results were used to compare different properties of the biosynthetic (intra- and extracellular) and synthetic SNPs in terms of shape, size, zeta potential, stability, and toxicity. The results confirmed lower toxicity of biosynthetic SNPs in-vitro assays, and their more stability with less aggregation compared to the synthetic ones. Also, the biosynthetic nanoparticles were found uniform and small. These nanoparticles may be useful for being employed as biosensors.

The osteogenesis of bacterial cellulose scaffold loaded with fisetin

Objectives

Bacterial cellulose (BC) has applications in medical science, it is easily synthesized, economic and purer compared to plant cellulose. The present study aimed to evaluate BC, a biocompatible natural polymer, as a scaffold for the bone marrow mesenchymal stem cells (BMSCs) loaded with fisetin, a phytoestrogen.

Materials and Methods

BC hydrogel scaffold was prepared from Gluconaceter xylinus and characterized through scanning electron microscopy (SEM). Biocompatibility of BC was measured by MTT assay, BMSCs were obtained from femur of rat and the osteogenic potential of the BC scaffold cultured with BMSCs and loaded with fisetin, was investigated by measuring the alkaline phosphatase (ALP) activity, alizarin red staining (ARS) and real-time PCR in terms of osteoblast-specific marker, osteocalcin (OCN) and osteopontin (OPN).

Results

Biocompatibility results did not show any toxic effects of BC scaffold on BMSCs, while it increased cell viability. The data showed that BC loaded fisetin differentiated BMSCs into osteoblasts as demonstrated by ALP activity assays and ARS in vitro. Moreover, results from gene expression assay showed the expression of OCN and OPN genes was increased in cells that were seeded on the BC scaffold loaded with fisetin.

Conclusion

According to the results of the present study, BC loaded with fisetin is an effective strategy to promote osteogenic differentiation and a proper localized delivery system, which could be a potential candidate in bone tissue engineering.

Cardiogenic effects of characterized Geum urbanum extracts on adipose-derived human mesenchymal stem cells

Stem cell therapy is considered as a promising treatment for cardiovascular diseases. Adipose-derived mesenchymal stem cells (ADMSCs) have the ability to undergo cardiomyogenesis. Medicinal plants are effective and safe candidates for cell differentiation. Therefore, the aim of our study was to investigate cardiogenic effects of characterized (HPLC–UV) extracts of Geum urbanum on ADMSCs of adipose tissue. The methanolic extracts of the root and aerial parts of G. urbanum were obtained and MTT assay was used for studying their cytotoxic effects. Then, cells were treated with 50 or 100 μg/mL of the extracts from root and aerial parts of G. urbanum. MTT assay showed that the extracts of G. urbanum did not have any toxic effects on ADMSCs. Immunostaining results showed increase in the expression of α-actinin and cardiac troponin I (cTnI), and quantitative real-time reverse-transcription PCR data confirmed the upregulation of ACTN, ACTC1, and TNNI3 genes in ADMSCs after treatment. According to HPLC fingerprinting, some cardiogenic effects of G. urbanum extracts are probably due to ellagic and gallic acid derivatives. Our findings indicated that G. urbanum extracts effectively upregulated some essential cardiogenic markers, which confirmed the therapeutic role of this plant as a traditional cardiac medicine.

Characterization of a green nanocomposite prepared from soluble soy bean polysaccharide/Cloisite 30B and evaluation of its toxicity

The present paper aims to elucidate the structural, thermal and mechanical properties of soybean polysaccharide (SSPS)/Cloisite 30B. Tensile strength of the nanocomposite films improved with incorporation of nanoparticles, whereas elongation at break decreased. Surface roughness of the samples increased with the addition of nanoclay. Neat SSPS film and SSPS-1% Cloisite 30B had a relatively smooth surface with no irregularities, while for the samples containing 3 and 7% Cloisite 30B, the surface was rough. DSC analysis demonstrated that following an increase in nanoparticles content, the melting temperature of the nanocomposite elevated, whereas, glass transition temperature decreased. The results of antibacterial activity indicated that Cloisite 30B could inhibit the growth of Salmonella typhi PTCC 1609, Staphylococcus epidermis PTCC 1114 (ATCC 12228) and Listeria monocytogenes PTCC 1165. SSPS-Cloisite 30B nanocomposite could not inhibit the growth of Aspergillus niger. The results demonstrated that the migration of nanoparticles might happen into deionized water as a food simulant, but they could not migrate into bread as a food model. Furthermore, it was found that Cloisite 30B nanoparticles had cytotoxicity effect, and thus, it is recommended that Cloisite 30B/SSPS nanocomposites be used only for the packaging of solids foods such as bread.

Cardiomyogenic differentiation of human adipose-derived mesenchymal stem cells transduced with Tbx20-encoding lentiviral vectors

Ischemic heart disease often results in myocardial infarction and is the leading cause of mortality and morbidity worldwide. Improvement in the function of infarcted myocardium is a main purpose of cardiac regenerative medicine. One possible way to reach this goal is via stem cell therapy. Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types but display limited cardiomyogenic differentiation potential. Members of the T-box family of transcription factors including Tbx20 play important roles in heart development and cardiomyocyte homeostasis. Therefore, in the current study, we investigated the potential of Tbx20 to enhance the cardiomyogenic differentiation of human adipose-derived MSCs (ADMSCs). Human ADMSCs were transduced with a bicistronic lentiviral vector encoding Tbx20 (murine) and the enhanced green fluorescent protein (eGFP) and analyzed 7 and 14 days post transduction. Transduction of human ADMSCs with this lentiviral vector increased the expression of the cardiomyogenic differentiation markers ACTN1, TNNI3, ACTC1, NKX2.5, TBX20 (human), and GATA4 as revealed by RT-qPCR. Consistently, immunocytological results showed elevated expression of α-actinin and cardiac troponin I in these cells in comparison to the cells transduced with control lentiviral particles coding for eGFP alone. Accordingly, forced expression of Tbx20 exerts cardiomyogenic effects on human ADMSCs by increasing the expression of cardiomyogenic differentiation markers at the RNA and protein level.

In vitro evaluation of antibacterial activity of verbascoside, lemon verbena extract and caffeine in combination with gentamicin against drug-resistant Staphylococcus aureus and Escherichia coli clinical isolates

OBJECTIVE

In recent years, there has been an increasing interest in using herbal products to overcome bacterial resistance. The aim of this study was to investigate the effect of lemon verbena aqueous extract, verbascoside and caffeine in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus and Escherichia coli strains.

MATERIALS AND METHODS

The MIC and MBC values of different antibacterial agents against bacterial strains were determined. The effect of co-administration lemon verbena extract, verbascoside, and caffeine and gentamicin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI).

RESULTS

Herbal extract, verbascoside and caffeine alone showed no inhibitory effects on any of the bacterial strains (at doses up to 200 g/ml). Herbal extract, verbascoside and caffeine were able to decrease the MIC of gentamicin against the standard resistant strains and two clinical isolates. Among these combinations, the co-administration of verbascoside and gentamicin was more effective and synergistic activities (FICI<1)‏ against clinical isolates were observed.‏.

CONCLUSION

The results of the present study revealed that herbal extract, verbascoside and caffeine potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and E. coli.

Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa: - Combination therapy against resistant bacteria

Objectives:

Bacterial resistant infections have become a global health challenge and threaten the society’s health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa).

Methods:

The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI).

Results:

The MICs of gentamicin against bacterial strains were in the range of 0.312 - 320 μg/mL. The MIC values of both types of catechins were 62.5 - 250 μg/ mL. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin.

Conclusion:

The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

Different behavior of Staphylococcus epidermidis in intracellular biosynthesis of silver and cadmium sulfide nanoparticles: more stability and lower toxicity of extracted nanoparticles

Chemical reagents that are used for synthesis of nanoparticles are often toxic, while biological reagents are safer and cost-effective. Here, the behavior of Staphylococcus epidermidis (ATCC 12228) was evaluated for biosynthesis of silver nanoparticles (Ag-NPs) and cadmium sulfide nanoparticles (CdS-NPs) using TEM images intra- and extracellularly. The bacteria only biosynthesized the nanoparticles intracellularly and distributed Ag-NPs throughout the cytoplasm and on outside surface of cell walls, while CdS-NPs only formed in cytoplasm near the cell wall. A new method for purification of the nanoparticles was used. TEM images of pure CdS-NPs confirmed biosynthesis of agglomerated nanoparticles. Biosynthetic Ag-NPs were more stable against bright light and aggregation reaction than synthetic Ag-NPs (prepared chemically) also biosynthetic Ag-NPs displayed lower toxicity in in vitro assays. CdS-NPs indicated no toxicity in in vitro assays. Biosynthetic nanoparticles as product of the detoxification pathway may be safer and more stable for biosensors.

Evaluation, prediction and optimization the ultrasound-assisted extraction method using response surface methodology: antioxidant and biological properties of Stachys parviflora L

OBJECTIVES

To optimize the extraction method using response surface methodology, extract the phenolic compounds, and identify the antioxidant and biological properties of Stachys parviflora L. extracts.

MATERIALS AND METHODS

Maceration and ultrasound-assisted extraction (UAE) (4, 7, 10 min treatment time, 40, 70, 100 % high-intensity and 60, 80, 100 % (v v-1) methanol purity) were applied to obtain the extracts. SEM was conducted to provide the microstructure of the extracted plant. MICs (colorimetric assay), MFCs (colony diameter), total phenolic content, total flavonoid content, radical scavenging capacity and extraction efficiency were determined. HPLC analysis was applied to measure the existent phenolic compounds.

RESULTS

A quadratic model (4 min treatment time, 74.5 % high-intensity and 74.2 % solvent purity) was suggested as the best (TPC: 20.89 mg GAE g-1 d.m., TFC: 6.22 mg QEs g-1 d.m., DPPH IC50: 21.86 µg ml-1 and EE: 113.65 mg g-1 d.m.) UAE extraction model. The optimized UAE extract was generally more effective against Gram-positive microorganisms (MIC: 10-20; MBC: 10-40 (mg ml-1)) than Gram-negative ones (MIC: 40; MBC: >40 (mg ml-1)). Moreover, it (MGI: 2.32-100 %) revealed more anti-mold activity than maceration (MGI: <28.77 %). Explosive disruption of the cell walls, therefore, enhanced extraction yield by acoustic cavitation, was elucidated using SEM. Caffeic acid, tannic acid, quercetin, trans ferulic acid and rosmarinic acid were determined as the phenolic compounds in the optimized extract.

CONCLUSION

RSM optimization was successfully applied for UAE from S. parviflora. The considerable antioxidant and biological properties were attributed to the phenolic compounds.

The novel effect of cis-2-decenoic acid on biofilm producing Pseudomonas aeruginosa

Microbial biofilms are a main cause of many chronic infections and mortalities, such as dental caries, cystic fibrosis, osteoradionecrosis, urinary tract infections and native valve endocarditis. These polymeric matrices are sessile communities with different rules from those forms via known planktonic bacteria. One of the important biofilm-producing human pathogens is <em>Pseudomonas aeruginosa</em>, which causes death in the majority of people who suffer from cystic fibrosis, AIDS, burns and neutropenic cancer. To find a method for controlling the growth and resistance of <em>P. aeruginosa</em> biofilm, this study investigated the dispersion induction of this microorganism with a diffusible signal factor (DSF), <em>cis</em>-2-decenoic acid (CDA), in combination with Tobramycin as a useful antibiotic. Our findings confirmed that although CDA did not act as a dispersion inducer in this experiment, it did show an antimicrobial effect and decreased the MIC of Tobramycin. These results suggested that research on the probable new effects of DSF molecules will result in advances in the control of biofilm infections.

Combination of anti-tuberculosis drugs with vitamin C or NAC against different Staphylococcus aureus and Mycobacterium tuberculosis strains

BACKGROUNDS

Hepatotoxicity due to anti tuberculosis drugs, rifampin and isoniazid, is a major problem in tuberculosis patients. Vitamin C, an antioxidant, and N-acetyl cysteine (NAC), a scavenger of active metabolites, reduce the hepatotoxicity. The aim of present study was to investigate the effect of vitamin C and NAC individually on the antibacterial activity of anti tuberculosis drugs against Mycobacterium tuberculosis and Staphylococcus aureus strains.

METHODS

The MICs of each compound against all strains were determined in 96 wells plate. Rifampin was tested at serial two fold concentrations alone or in combination with NAC or vitamin C.

RESULTS

The MIC of rifampin against different strains of S. aureus was 0.008-0.032 μg/ml. The MIC of rifampin and isoniazid against M. tuberculosis strains were 40 and 0.2 μg/ml, respectively. Vitamin C and NAC had no antibacterial activity against all strains. MIC of rifampin was reduced two fold by combination with vitamin C for all S. aureus strains, while NAC did not affect the antibacterial activity of rifampin. Vitamin C and NAC had remarkable effects on the antibacterial activity of anti-tuberculosis drugs against M. tuberculosis.

CONCLUSIONS

Synergistic effects were observed between rifampin or isoniazid and vitamin C against all tested strains. However, combination therapy of rifampin and isoniazid with NAC was not being effective. This study highlighted the advantages of combination of anti-tuberculosis drugs and vitamin C to eradicate the microbial infections.

Role of apoptosis in pathogenesis and treatment of bone-related diseases

In this article, bone cells and their intercellular communications have been reviewed. Gap junctions and hemichannels are the main routes of interactions in bone tissue. They play a substantial role in survival and cell death, since pro-apoptotic signals can propagate through them. Different adhesion molecules are required for apoptosis, particularly caspase family as well as noncaspase proteases. The disruption outcome of apoptosis could result in bone-related diseases such as osteonecrosis. Anti-apoptotic strategies include inhibition of caspase, poly [ADP-ribose] polymerase (PARP), and Bcl-2 proteins as well as induction of the PKB/Akt pathway and inhibitors of apoptosis (IAP) family of proteins. Thus, understanding the mechanism of apoptosis gives detailed insights of anti-apoptotic molecular targets. Based on these targets, different treatments were designed and produced such as estrogen replacement therapy, administration of different bisphosphonates, raloxifene, calcitonin, sodium fluoride, calcium, and vitamin D. As a result, new applicable drugs for treatment of related bone problems can be proposed for clinical approach especially in the early stage of diseases.

UV Spectrophotometric Determination and Validation of Hydroquinone in Liposome

The method has been developed and validated for the determination of hydroquinone in liposomal formulation. The samples were dissolved in methanol and evaluated in 293 nm. The validation parameters such as linearity, accuracy, precision, specificity, limit of detection (LOD) and limit of quantitation (LOQ) were determined. The calibration curve was linear in 1-50 µg/mL range of hydroquinone analyte with a regression coefficient of 0.9998. This study showed that the liposomal hydroquinone composed of phospholipid (7.8 %), cholesterol (1.5 %), alpha ketopherol (0.17 %) and hydroquinone (0.5 %) did not absorb wavelength of 293 nm if it diluted 500 times by methanol. The concentration of hydroquinone reached 10 µg/mL after 500 times of dilution. Furthermore, various validation parameters as per ICH Q2B guideline were tested and found accordingly. The recovery percentages of liposomal hydroquinone were found 102 ± 0.8, 99 ± 0.2 and 98 ± 0.4 for 80%, 100% and 120% respectively. The relative standard deviation values of inter and intra-day precisions were <%2. LOD and LOQ were 0.24 and 0.72 µg/mL respectively.

Black cumin (Nigella sativa) and its constituent (thymoquinone): a review on antimicrobial effects

Nigella sativa seeds have wide therapeutic effects and have been reported to have significant effects against many ailments such as skin diseases, jaundice, gastrointestinal problems, anorexia, conjunctivitis, dyspepsia, rheumatism, diabetes, hypertension, intrinsic hemorrhage, paralysis, amenorrhea, anorexia, asthma, cough, bronchitis, headache, fever, influenza and eczema. Thymoquinone (TQ) is one of the most active constituent and has different beneficial properties. Focus on antimicrobial effects, different extracts of N. sativa as well as TQ, have a broad antimicrobial spectrum including Gram-negative, Gram-positive bacteria, viruses, parasites, schistosoma and fungi. The effectiveness of N. sativa seeds and TQ is variable and depends on species of target microorganisms. The present review paper tries to describe all antimicrobial activities that have been carried out by various researchers.