Management of Cardiovascular Diseases by Short-Chain Fatty Acid Postbiotics

PURPOSE OF REVIEW

Global health concerns persist in the realm of cardiovascular diseases (CVDs), necessitating innovative strategies for both prevention and treatment. This narrative review aims to explore the potential of short-chain fatty acids (SCFAs)-namely, acetate, propionate, and butyrate-as agents in the realm of postbiotics for the management of CVDs.

RECENT FINDINGS

We commence our discussion by elucidating the concept of postbiotics and their pivotal significance in mitigating various aspects of cardiovascular diseases. This review centers on a comprehensive examination of diverse SCFAs and their associated receptors, notably GPR41, GPR43, and GPR109a. In addition, we delve into the intricate cellular and pharmacological mechanisms through which these receptors operate, providing insights into their specific roles in managing cardiovascular conditions such as hypertension, atherosclerosis, heart failure, and stroke. The integration of current information in our analysis highlights the potential of both SCFAs and their receptors as a promising path for innovative therapeutic approaches in the field of cardiovascular health. The idea of postbiotics arises as an optimistic and inventive method, presenting new opportunities for preventing and treating cardiovascular diseases.

Structure, Function, and Physicochemical Properties of Pore-forming Antimicrobial Peptides

Antimicrobial peptides (AMPs), a class of antimicrobial agents, possess considerable potential to treat various microbial ailments. The broad range of activity and rare complete bacterial resistance to AMPs make them ideal candidates for commercial development. These peptides with widely varying compositions and sources share recurrent structural and functional features in mechanisms of action. Studying the mechanisms of AMP activity against bacteria may lead to the development of new antimicrobial agents that are more potent. Generally, AMPs are effective against bacteria by forming pores or disrupting membrane barriers. The important structural aspects of cytoplasmic membranes of pathogens and host cells will also be outlined to understand the selective antimicrobial actions. The antimicrobial activities of AMPs are related to multiple physicochemical properties, such as length, sequence, helicity, charge, hydrophobicity, amphipathicity, polar angle, and also self-association. These parameters are interrelated and need to be considered in combination. So, gathering the most relevant available information will help to design and choose the most effective AMPs.

Amino acid-mPEGs: Promising excipients to stabilize human growth hormone against aggregation

Objectives

Today, the non-covalent PEGylation methods of protein pharmaceuticals attract more attention and possess several advantages over the covalent approach. In the present study, Amino Acid-mPEGs (aa-mPEGs) were synthesized, and the human Growth Hormone (hGH) stability profile was assessed in their presence and absence.

Materials and Methods

aa-mPEGs were synthesized with different amino acids (Trp, Glu, Arg, Cys, and Leu) and molecular weights of polymers (2 and 5 KDa). The aa-mPEGs were analyzed with different methods. The physical and structural stabilities of hGH were analyzed by SEC and CD spectroscopy methods. Physical stability was assayed at different temperatures within certain intervals. Molecular dynamics (MD) simulation was used to realize the possible mode of interaction between protein and aa-mPEGs. The cell-based method was used to evaluate the cytotoxicity.

Results

HNMR and FTIR spectroscopy indicated that aa-mPEGs were successfully synthesized. hGH as a control group is known to be stable at 4 ^°C; a pronounced change in monomer degradation is observed when stored at 25 ^°C and 37 ^°C. hGH:Glu-mPEG 2 kDa with a molar ratio of 1:1 to the protein solution can significantly increase the physical stability. The CD spectroscopy method showed that the secondary structure of the protein was preserved during storage. aa-mPEGs did not show any cytotoxicity activities. The results of MD simulations were in line with experimental results.

Conclusion

This paper showed that aa-mPEGs are potent excipients in decreasing the aggregation of hGH. Glu-mPEG exhibited the best-stabilizing properties in a harsh environment among other aa-mPEGs.

The potential of probiotics for treating skin disorders: A concise review

Probiotics are defined as "live microorganisms that, when administered in adequate amounts, ‎confer a health benefit on the host". In recent years, the cosmetic industries have tried to develop a ‎number of products classified as probiotics. They can exert their benefits at the skin level ‎because of their favorite properties, and they could prevent and treat skin diseases and represent an emerging area for skin health. The antibacterial and immunomodulatory properties make them promising candidates to target skin disorders including acne, psoriasis, and atopic dermatitis and aid wound healing. The scientific reports show that specific probiotic strains ‎can modulate cutaneous microflora, skin immune system, lipid barrier, and finally, skin health ‎preservation. This review summarizes the most relevant evidence from scientific literature concerning potential topical applications of probiotics in dermatology. Altogether, ‎the evidence reported here affords the possibility of designing new strategies based on a topical ‎approach to prevent and treat cutaneous disorders.‎.

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.

Phytochemicals: A Promising Weapon in the Arsenal against Antibiotic-Resistant Bacteria

The extensive usage of antibiotics and the rapid emergence of antimicrobial-resistant microbes (AMR) are becoming important global public health issues. Many solutions to these problems have been proposed, including developing alternative compounds with antimicrobial activities, managing existing antimicrobials, and rapidly detecting AMR pathogens. Among all of them, employing alternative compounds such as phytochemicals alone or in combination with other antibacterial agents appears to be both an effective and safe strategy for battling against these pathogens. The present review summarizes the scientific evidence on the biochemical, pharmacological, and clinical aspects of phytochemicals used to treat microbial pathogenesis. A wide range of commercial products are currently available on the market. Their well-documented clinical efficacy suggests that phytomedicines are valuable sources of new types of antimicrobial agents for future use. Innovative approaches and methodologies for identifying plant-derived products effective against AMR are also proposed in this review.

An Overview of Different Methods for Aminoglycoside Residue Determination

Aminoglycosides (AGs) are chemical substances that exist in the bacteriologic category of traditional antibiotic (AB) therapy. The importance of the determination of AG as has been described in many situations by researchers. Because of the narrow therapeutic ranges of AGs, considerable efforts have been attributed to the analysis of AGs in pharmaceutical preparations, serum, and urine specimens for therapeutic drug monitoring purposes. Residues of ABs in many different cases like environment and human food, causes a major concern, as prolonged exposure to ABs is a serious health hazard, related to both side effects of prolonged use and the risk of developing bacterial resistance to various ABs. The major challenge is finding a sensitive and reliable method to determine AGs in a complex matrix. The microbiological assay was a simple and old method for the determination of AGs. Chromatography and spectroscopy methods are the main instrumental methods for analysis that have been employed for these purposes. Biosensor based instrumental systems have been recently used to determine the AG residues in many cases. Each of these methods has its advantages and disadvantages. This review summarizes different ways (microbiological methods, instrumental methods, and biosensor) for the determination of AGs in all cases. Different databases including PubMed, Scopus, and Web of Science with the words of AGs determination and related words for antimicrobial keywords searched without time limitation.

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.

In-vitro Release Evaluation of Growth Hormone from an Injectable In-Situ Forming Gel Using PCL-PEG-PCL Thermosensitive Triblock

OBJECTIVE

An injectable long acting In-Situ Forming Gel (ISFG) of human Growth Hormone (hGH) was prepared by using triblock PCL-PEG-PCL (Mw 1500-1500-1500). Ring-Opening Polymerization (ROP) of triblock using microwave was applied.

METHODS

The BCA protein assay Kit was used to determine the concentration of hGH in the in-vitro release medium. Finally, Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) tests and Circular Dichroism (CD) spectrum were done to approve the stability of released hGH. The result of ROP demonstrated that the proportion of PCL to PEG accorded with the initial molar ratio of the monomers. The cross-section of the Surface Electron Microscopy (SEM) indicated the porous framework of the hydrogel could load the drug into its tridimensional matrixes structure. There is the low initial burst release of hGH from the supramolecular hydrogel.

RESULTS

The maximum in-vitro release of hGH was 71.2 % ± 1.5 that were due to hGH degrading after this time (21 days). The CD spectrum and SDS-PAGE results confirmed the stability of hGH during invitro release evaluation.

CONCLUSION

The results suggest that the sustained-release formulation using PCL-PEG-PCL can be applied to control the release of hGH.

Preparation and in vivo evaluation of nanoliposomes containing vancomycin after intravitreal injection in albino rabbits

Objective(s):

The in vivo efficacy of nanoliposomal formulation of vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) assessed.

Materials and Methods:

Nanoliposomal formulations were prepared and characterized. The in vivo study was carried out on rabbits which received liquid culture medium containing MRSA under anesthesia. After 48 hr, the eyes treated with the liposomal and free form of vancomycin. The rabbits were euthanized at predesignate intervals at 12, 24, 48, 96, 144 hr intervals injection. The antibacterial activity of different vancomycin formulations was assayed by the time killing method.

Results:

The zeta potential, mean sizes and encapsulation efficacy of liposomal vancomycin were 29.7 mV, 381.93±30.13 nm and 47%, respectively. The results of time–killing studies indicated that the liposomal formula was more effective than the free form of vancomycin.

Conclusion:

The results of this study revealed that liposomal vancomycin formulation is a powerful nano-antibacterial agent to combat infectious endophthalmitis.

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.

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.

Determination of Optimum Excipients for Platanus orientalis Pollen Extract by Accelerating Chemical Stability Test and Their Synergistic Effect

BACKGROUND

The quality of extracts used in the skin prick test directly influences the interpretation of the test. Accordingly, the outcomes and effectiveness of immunotherapy for the management of IgE-mediated allergies depend on the quality of the extracts used. Excipients, which are pharmacologically inert ingredients, are intentionally added to the active ingredients. The aim of this study was to address optimum excipients for stability Platanus (P.) orientalis extract.

METHODS

In this study the excipients examined were l-lysine (20 mM), l-cysteine (20 mM), albumin (0.5%), sorbitol (2%), sucrose (750 mM), trehalose (20 mM), D-mannitol (2% w/v), urea (100 mM) and Tween-20 (0.1%). Their effects on P. orientalis extract stability were analyzed using an inhibition enzyme linked immune assay at 37 °C.

RESULTS

A mixture of lysine (20 mM), trehalose (20 mM), and D-mannitol (2% w/v) conferred the greatest stability on the P. orientalis extract.

CONCLUSION

The P. orientalis extract stability was increased by a mixture of lysine (20 mM), trehalose (20 mM), and D-mannitol.

Antibacterial activity of flavonoids and their structure-activity relationship: An update review

Based on World Health Organization reports, resistance of bacteria to well-known antibiotics is a major global health challenge now and in the future. Different strategies have been proposed to tackle this problem including inhibition of multidrug resistance pumps and biofilm formation in bacteria and development of new antibiotics with novel mechanism of action. Flavonoids are a large class of natural compounds, have been extensively studied for their antibacterial activity, and more than 150 articles have been published on this topic since 2005. Over the past decade, some promising results were obtained with the antibacterial activity of flavonoids. In some cases, flavonoids (especially chalcones) showed up to sixfold stronger antibacterial activities than standard drugs in the market. Some synthetic derivatives of flavonoids also exhibited remarkable antibacterial activities with 20- to 80-fold more potent activity than the standard drug against multidrug-resistant Gram-negative and Gram-positive bacteria (including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). This review summarizes the ever changing information on antibacterial activity of flavonoids since 2005, with a special focus on the structure-activity relationship and mechanisms of actions of this broad class of natural compounds.

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.

Solid lipid nanoparticles carrying Eugenia caryophyllata essential oil: the novel nanoparticulate systems with broad-spectrum antimicrobial activity

In this study, solid lipid nanoparticles containing Eugenia caryophyllata essential oil (SLN-EO) were prepared by high-shear homogenization and ultrasound methods, and used to eradicate pathogens. SLN formulations were evaluated for their size, zeta potential and encapsulation efficacy (EE). The morphological and thermal properties of the formulations were analysed by transmission electron microscopy (TEM) and differential scanning calorimetry methods. The lead formulations were chosen and tested with minimum inhibitory concentration (MIC), MBC and time-kill methods to investigate the antimicrobial activity against Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. The particle size of three final formulations were 397 ± 10·1, 786·9 ± 11 and 506·4 ± 22 nm respectively. The zeta potential of all formulations was negative values. The size of the formulations was slightly increased during 3 months storage at 25°C. The TEM imaging showed that formulation had spherical shape. The EE of EO was estimated approximately 70%. MIC and MCC values of SLN-EO were lower than those of the oil alone. The time-kill studies showed that SLN-EO was either equivalent to or better than EO (P-value <0·05). The results of this study highlighted the effectiveness of SLN formulations against human pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

Microbial resistance to antibiotics is a major problem in the treatment of diseases. Therefore, overcoming antimicrobial resistance is an urgent need. Drug delivery via nanoparticles and applying natural products are promising approaches to reduce microbial resistance. This study is designed to evaluate the antimicrobial activity of solid lipid nanoparticles (SLN) containing Eugenia caryophyllata essential oil (EO) against human pathogens. The results indicated that the antimicrobial activity of EO was remarkably enhanced when encapsulated in SLN.

Immunoadjuvant potential of cross-linked dextran microspheres mixed with chitosan nanospheres encapsulated with tetanus toxoid

CONTEXT

Nasal mucosa is a desirable route for mucosal vaccine delivery. Mucosal co-administration of chitosan nanoparticles with absorption enhancers such as cross-linked dextran microspheres (CDM, Sephadex^®) is a promising antigen delivery system.

OBJECTIVE

In the current study, the chitosan nanospheres loaded with tetanus toxoid (CHT:TT NPs) was prepared and characterized. The immune responses against tetanus toxoid after nasal administration of CHT:TT NPs alone or mixed with CDM were also determined.

MATERIALS AND METHODS

Chitosan nanospheres were prepared by ionic gelation method. Particle size, releasing profile and antigen stability were evaluated by dynamic light scattering, diffusion chamber and SDS-PAGE methods, respectively. Rabbits were nasally immunized with different formulations loaded with 40 Lf TT. After three times immunizations with 2 weeks intervals, sera IgG titres and nasal lavage sIgA titres were determined.

RESULTS

Mean size of CHT NPs and CHT:TT NPs were 205 ± 42 nm and 432 ± 85 nm, respectively. The release profile showed that 42.4 ± 10.5% of TT was released after 30 min and reached to a steady state after 1.5 h. Stability of encapsulated TT in nanospheres was confirmed by SDS-PAGE. The antibody titres showed that CHT:TT NPs-induced antibody titres were higher than TT solution. CHT NPs mixed with CDM induced the systemic IgG and nasal lavage sIgA titres higher than intranasal administration of TT solution (p < 0.001).

DISCUSSION AND CONCLUSION

As the results indicated, these CHT:TT NPs when co-administered with CDM were able to induce more immune responses and have the potential to be used in mucosal immunization.

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.

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.

Foetithiophenes C-F, thiophene derivatives from the roots of Ferula foetida

CONTEXT

Ferula foetida Regel (Apiaceae) is an Iranian medicinal plant with various biological activities including antispasmodic and anthelmintic.

OBJECTIVE

The sulfur compounds from the roots of F. foetida were isolated and characterized to test their cytotoxic and antimicrobial activities.

MATERIALS AND METHODS

The methanolic extract of the roots of F. foetida was fractionated using silica column chromatography. The components of each fraction were further purified using RP-HPLC. Their structures were elucidated by 1- and 2-D NMR spectroscopy as well as HREIMS. Their cytotoxic and antimicrobial activities were evaluated using Alamar Blue assay and broth microdilution method, respectively.

RESULTS

Four new thiophene derivatives, namely foetithiophenes C-F (3-6), together with four known compounds, foetithiophenes A (1) and B (2), coniferaldehyde, and sinapic aldehyde, were isolated from the roots of F. foetida. Antimicrobial activities were observed in particular against the Gram-positive bacteria. The best antimicrobial activity was observed for compound 6 against B. cereus with a MIC value 50 µg/mL. The tested compounds did not show cytotoxic properties against MCF-7 and K562 cells.

CONCLUSION

Four new thiophene derivatives including foetithiophenes C-F (3-6) were characterized from the roots of F. foetida. Foetithiophene F (6) exhibited the most potent activity against the Gram-positive bacteria B. cereus.

Injectable supramolecular hydrogel from insulin-loaded triblock PCL-PEG-PCL copolymer and γ-cyclodextrin with sustained-release property

Supramolecular hydrogels formed by cyclodextrins and polymers have been widely investigated as a biocompatible, biodegradable and controllable drug delivery system. In this study, a supramolecular hydrogel based on biodegradable poly(caprolactone)-poly(ethylene glycol)-poly(caprolactone) (PCL-PEG-PCL) triblock copolymers and γ-cyclodextrin (γ-CD) was prepared through inclusion complexation as an injectable, sustained-release vehicle for insulin. The triblock copolymer PCL-PEG-PCL was synthesised by the ring-opening polymerisation method, using microwave irradiation. The polymerisation reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The supramolecular hydrogel was prepared in aqueous solution by blending an aqueous γ-CD solution with an aqueous solution of PCL-PEG-PCL triblock copolymer at room temperature. In vitro insulin release through the hydrogel system was studied. The relative surface hydrophobicity of standard and released insulin from the SMGel was estimated using 8-anilino-1-naphthalene sulfonic acid (ANS). Results of (1)HNMR and gel permeation chromatography revealed that microwave irradiation is a simple and reliable method for synthesis of PCL-PEG-PCL copolymer. Gelation occurred within a minute. The supramolecular hydrogel obtained by mixing 10.54% (w/v) γ-CD and 2.5% (w/v) copolymer had an excellent syringeability. Insulin was released up to 80% over a period of 20 days. Insulin kept its initial folding after formulating and releasing from SMGel. A supramolecular hydrogel based on complexation of triblock PCL-PEG-PCL copolymer with γ-cyclodextrin is a suitable system for providing sustained release of therapeutic proteins, with desirable flow behaviour.

Safranal-loaded solid lipid nanoparticles: evaluation of sunscreen and moisturizing potential for topical applications

OBJECTIVES

In the current study, sunscreen and moisturizing properties of solid lipid nanoparticle (SLN)-safranal formulations were evaluated.

MATERIALS AND METHODS

Series of SLN were prepared using glyceryl monostearate, Tween 80 and different amounts of safranal by high shear homogenization, and ultrasound and high-pressure homogenization (HPH) methods. SLN formulations were characterized for size, zeta potential, morphology, thermal properties, and encapsulation efficacy. The Sun Protection Factor (SPF) of the products was determined in vitro using transpore tape. The moisturizing activity of the products was also evaluated by corneometer.

RESULTS

The SPF of SLN-safranal formulations was increased when the amount of safranal increased. Mean particle size for all formulas was approximately 106 nm by probe sonication and 233 nm using HPH method. The encapsulation efficiency of safranal was around 70% for all SLN-safranal formulations.

CONCLUSION

The results conclude that SLN-safranal formulations were found to be effective for topical delivery of safranal and succeeded in providing appropriate sunscreen properties.

Eradication of methicillin-resistant Staphylococcus aureus infection by nanoliposomes loaded with gentamicin and oleic acid

CONTEXT

Methicillin-resistant Staphylococcus aureus (MRSA) infection with its high incidence is responsible for nosocomial infections. MRSA strains resistant to multiple antibiotics have emerged increasingly. Recently, combination therapy and efficient drug delivery systems are developed to treat infections.

OBJECTIVE

The aim of the present study was to evaluate antibacterial activities of combination of oleic acid and gentamicin against MRSA, in both free and liposomal forms, and in comparison with vancomycin.

MATERIALS AND METHODS

The antibacterial activities against MRSA ATCC 43300 were assessed by the determination of minimum inhibitory concentration (MIC), MBC, and Fractional Inhibitory Concentration Index (FICI). The time-kill assays were performed to evaluate the potency of antibacterial agents. Nanoliposomal formulations of gentamicin, oleic acid, and combination of gentamicin with oleic acid were prepared by the dehydration-rehydration (DRV) method and characterized for size, zeta potential, and encapsulation efficiency.

RESULTS

MIC values of gentamicin and oleic acid were 19.5 and >250 µg/ml, respectively. Synergetic effects were observed by the gentamicin and oleic acid combination; FICI was 0.5. Following incorporation of gentamicin into liposomal gentamicin and liposomal combination, the MIC values were reduced 15- and 27-fold, respectively. In comparison with vancomycin, liposomal combination was more effective in bacterial inhibition and killing. Liposomal combination was the most effective formula in time-kill study.

DISCUSSION AND CONCLUSION

Liposomal formulation showed a higher antibacterial activity in comparison with the free forms and vancomycin. These carriers can improve antimicrobial activity as well as reducing the effective concentration required and inducing rapid bacterial clearance.

Preparation and characterization of PLGA nanospheres loaded with inactivated influenza virus, CpG-ODN and Quillaja saponin

OBJECTIVES

The purpose of this study was preparation and evaluation of PLGA nanospheres containing the influenza virus and different adjuvants, Quillaja saponin (QS) and CpG-ODN.

MATERIALS AND METHODS

Nanospheres were prepared using the double emulsion-solvent evaporation method. The morphological and physicochemical properties were studied by scanning electron microscopy (SEM), determination of zeta potential, encapsulation efficiency and release profile.

RESULTS

The particle size of formulations was less than 1000 nm, except for formulations containing antigen. The results were confirmed with SEM images. Encapsulation efficiency of antigen, QS and CpG ODN were 80%, 62% and 31%, respectively. The zeta potential of nanospheres was about -30 mV. The burst release was observed for all encapsulates and reached to about 48%, 44% and 35% within 90 min for antigen, CpG-ODN and Qs content, respectively.

CONCLUSION

The formulations showed proper physicochemical properties. These nanospheres have good potential to be used as delivery systems/adjuvants for immunization against influenza.

Biofilm Formation by Staphylococcus epidermidis on Foldable and Rigid Intraocular Lenses

Background:

Biofilm formation of Staphylococcus epidermidis is a major etiological factor of inducing device-related infections.

Objectives:

The ability of biofilm formation by the S. epidermidis was assessed in vitro on two brands of foldable (hydrophilic) and two brands of rigid (hydrophobic) intraocular lens materials in order to investigate the role of lens material in postoperative endophthalmitis.

Materials and Methods:

To ensure reproducibility of biofilm formation on intraocular lenses, two strains of S. epidermidis and three quantification methods were performed. The S. epidermidis strains, DSMZ3270 (biofilm-producer) and ATCC12228 (non-biofilm-producer) were applied. Organisms were cultivated on disks of different brands of foldable hydrophilic Intra Ocular Lens (IOL) made of acrylic (Didar, Iran; (A) and Omni, India; (B)), and rigid hydrophobic IOL made of polymethyl methacrylate (PMMA; Didar, Iran; (C) and Hexavision, France; (D)). Biofilms were stained with crystal violet (CV) dye, which is an index of biofilm formation. The bacterial population was counted after biofilm homogenization. Scanning electron microscopy (SEM) was performed to examine the extent of biofilm formation.

Results:

Adherence of DSMZ3270 strain on both types of foldable and rigid IOLs, was significantly more than ATCC12228 (P < 0.001-0.05 and, P < 0.01-0.05, respectively). The bacterial populations between the lenses were significantly different (P < 0.05). Subsequent studies demonstrated significant differences between brands of foldable and PMMA IOLs. According to statistical analyses the incubation time influenced the biofilm formation on both types of IOLs which meant that by increasing incubation time, the biofilm formation increased. According to the SEM pictures, biofilm seems to be lysed at 72 hours.

Conclusions:

These data demonstrated that the attachment of bacteria to hydrophilic acrylic IOLs was more than hydrophobic PMMA ones independent of the brand. According to these results the bacterial strain might have more hydrophilic properties. Augmenting the biomass of biofilm by passing of time demonstrated the key role of time in biofilm formation on the IOL surfaces. The differences between IOL brands in the biofilm formation indicated the influence of design parameters for IOLs.

Investigation of the antibacterial activity and efflux pump inhibitory effect of co-loaded piperine and gentamicin nanoliposomes in methicillin-resistant Staphylococcus aureus

OBJECTIVE

Antibiotic resistance has stimulated the research for developing novel strategies that can prevent bacterial growth. Methicillin-resistant Staphylococcus aureus (MRSA), regarded as one of the most serious antibiotic-resistant bacteria which has been conventionally recognized as a nosocomial pathogen.

MATERIALS AND METHODS

Nanoliposomal formulations of piperine and gentamicin were prepared by dehydration-rehydration (DRV) method and characterized for size, zeta potential and encapsulation efficiency. Antibactericidal activities of liposomal and free forms were evaluated against MRSA ATCC 43300 by the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and fractional inhibitory concentration index (FICI). The time-kill studies were carried out to evaluate the potency of antibacterial agents. The effect of piperine on bacterial efflux pumps was also investigated.

RESULTS

MIC values of gentamicin and piperine were 32 and 100 µg/mL, respectively. Synergetic effects were observed by the combination of gentamicin and piperine and FICI was determined to be 0.5. Following incorporation of gentamicin into liposomal gentamicin and liposomal combination, the MIC values were reduced 16- and 32-fold, respectively. MBC values of gentamicin reduced 4 and 8 times following incorporation into gentamicin and combination liposomes, respectively. In comparison with vancomycin, liposomal combination was more effective in bacterial inhibition and killing. Liposomal combination was the most effective preparations in time-kill study. Our findings indicated that liposomal piperine was able to inhibit the efflux pump sufficiently.

CONCLUSION

The results of this study revealed that liposomal combination is a powerful nano-antibacterial agent to eradicate MRSA infection. This dual-loaded formulation was an effective approach for eradication of MRSA.

Preparation, characterization and antimicrobial study of a hydrogel (soft contact lens) material impregnated with silver nanoparticles

PURPOSE

Contact lenses that incorporate antimicrobial properties may reduce the risk for microbial-associated adverse events for lens wearers. The aim of this study was to assess the antimicrobial effects of silver nanoparticles (NP) when impregnated in a hydrogel material.

METHODS

Hydrogel disks, used as a proxy for soft contact lenses, were prepared with silver NPs to add an antimicrobial effect to the polymer. Six groups of disks were created, each with a different concentration of silver NPs. The antimicrobial effect of the hydrogels against Pseudomonas aeruginosa (ATCC15442) and Staphylococcus aureus (ATCC6538) was evaluated at 6, 24, 48 and 72 h.

RESULTS

Silver NP concentrations ranged from 20.71 to 98.06 μg/disk. All groups demonstrated excellent antibacterial effects against P. aeruginosa at each time point. After 6h all disks didn't exhibit desirable antibacterial activity against S. aureus; whereas except those with 20.71 μg silver NPs showed antibacterial activity at 24h and only the disks with 57.13 and 98.06 μg silver NPs showed antimicrobial activity at 48 and 72 h.

CONCLUSIONS

The development of contact lenses made of a silver NP-impregnated hydrogel material may bring antimicrobial effects sufficient to decrease the risk of microbial-related adverse events for lens wearers.