Antibacterial mechanism of artemisinin / beta-cyclodextrins against methicillin-resistant Staphylococcus aureus ( MRSA )

Investigating the differences in β-Cyclodextrin derivatives / Hyperoside inclusion complexes: Dissolution properties, thermal stability, and antioxidant activity

Investigating the structure-activity relationship between β-cyclodextrin derivatives and guest molecules is crucial for the rational design of β-CD inclusion complexes. This study encapsulated hyperoside (HYP) with β-CD, DM-β-CD, and HP-β-CD using a freeze-drying method. Docking studies revealed that the higher binding energy of the HP-β-CD/HYP complex (6.84 kcal/mol) was attributed to the insertion of HYP into the hydrophobic cavity of HP-β-CD. Comparatively, the DM-β-CD/HYP complex exhibited the highest dissolution rate at 93.63 %, surpassing β-CD/HYP (68.10 %), HP-β-CD/HYP (75.05 %), and HYP (60.34 %), which endowed DM-β-CD/HYP with enhanced free radical scavenging activity against DPPH (80.67 %) and ABTS+ (46.32 %). Molecular dynamics (MD) simulations indicated that hydrophobic interactions was instrumental in improving the solubility and bioavailability of HYP, while H-bonding was essential for the stability of the β-CDs. DSC and MD simulations under varying temperatures demonstrated that increased temperature negatively impacted system stability, with H-bonding being critical for the thermal stability.

Development and characterization of farnesol complexed in β- and hydroxypropyl-β-cyclodextrin and their antibacterial activity

Farnesol (FAR) belongs to terpenes group and is a sesquiterpene alcohol and a hydrophobic compound, which can be extracted from natural sources or obtained by organic chemical or biological synthesis. Recent advances in the field of nanotechnology allow the drawbacks of low drug solubility, which can improve the drug therapeutic index. Therefore, this study aimed to prepare the FAR inclusion complexes with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) through freeze-drying method, proposing their physicochemical characterization, comparing their toxicity, and evaluating their in vitro antibacterial activity. Initially, physical mixture and freeze-dried inclusion complexes of FAR/β-CD and FAR/HP-β-CD were obtained in the molar ratio (1:1). The samples were characterized by DSC, TG/DTG, FTIR, PXRD, SEM, pHPZC, and the complexation efficiency were performed by HPLC. In vivo toxicity assay was performed using Tenebrio molitor larvae to determine the LD50 and toxic dose of the samples. Also, it was proposed that the evaluation of the fluorescence suppression of Bovine Serum Albumin and the antibacterial activity. The complexation of FAR was evidenced with β-CD and HP-β-CD by the characterization techniques analyzed. The complexation efficiency of FAR/β-CD and FAR/HP-β-CD were 73,53 % and 74.12 %, respectively. The inclusion complexes demonstrated a reduction in toxicity, as evidenced by lower toxic and LD50 doses compared to the free FAR. The inclusion complexes induced conformational changes in BSA, suggesting that they reached the subdomains containing tryptophan residues. In terms of antibacterial activity, FAR/β-CD and FAR/HP-β-CD did not exhibit significant MIC results compared to free FAR, except for FAR/HP-β-CD against S. aureus ATCC 25923.

Black pepper essential oil nanoemulsion inhibits Colletotrichum gloeosporioides by regulating respiratory metabolism

Colletotrichum gloeosporioides (C. gloeosporioides) is widely distributed pathogen responsible for postharvest losses in fruits and vegetables. Black pepper essential oil (BPEO) has emerged as natural antifungal agent that effectively inhibits C. gloeosporioides growth. However, the precise mechanism remains incompletely understood. This research investigates the suppressive properties of BPEO nanoemulsion on C. gloeosporioides and its impact on the respiratory metabolism. Results indicated that 2 MIC BPEO nanoemulsion have the best antifungal effect. Mechanistically, 2 MIC BPEO nanoemulsion can better suppress key enzymes connected to the Tricarboxylic Acid (TCA) cycle and Embden-Meyerhof-Parnas (EMP) pathway, hence reducing the C. gloeosporioides respiration rate. The total respiratory rate decreased by 60.54%, after 2 MIC BPEO nanoemulsion treatment. In conclusion, the BPEO nanoemulsion effectively mitigates fungal proliferation and reproduction by downregulating relevant enzymes expression. However, it is necessary to further expand the research on the regulation mechanism of enzyme activity at gene and protein level.

Cinnamaldehyde nanoemulsion decorated with rhamnolipid for inhibition of methicillin-resistant Staphylococcus aureus biofilm formation: in vitro and in vivo assessment

Background

Staphylococcus aureus (S. aureus) biofilm associated infections are prevalent and persistent, posing a serious threat to human health and causing significant economic losses in animal husbandry. Nanoemulsions demonstrate significant potential in the treatment of bacterial biofilm associated infections due to their unique physical, chemical and biological properties. In this study, a novel cinnamaldehyde nanoemulsion with the ability to penetrate biofilm structures and eliminate biofilms was developed.

Methods

The formulation of cinnamaldehyde nanoemulsion (Cin-NE) combined with rhamnolipid (RHL) was developed by self-assembly, and the efficacies of this formulation in inhibiting S. aureus biofilm associated infections were assessed through in vitro assays and in vivo experiments by a mouse skin wound healing model.

Results

The particle size of the selected Cin-NE formulation was 13.66 ± 0.08 nm, and the Cin-RHL-NE formulation was 20.45 ± 0.25 nm. The selected Cin-RHL-NE formulation was stable at 4, 25, and 37°C. Furthermore, the Minimum Inhibitory Concentration (MIC) value of Cin-RHL-NE against MRSA was two-fold lower than drug solution. Confocal laser scanning microscopy (CLSM) revealed the superior efficacy of Cin-RHL-NE in eradicating MRSA biofilms while maintaining the Cin's inherent functional properties. The efficacy of Cin-RHL-NE in the mouse skin wound healing model was superior to other formulation.

Conclusion

These findings highlight the potential of the formulation Cin-RHL-NE for eradicating biofilms, and effective in treating notoriously persistent bacterial infections. The Cin-RHL-NE can used as a dosage form of Cin application to bacterial biofilm associated infections.

Antimicrobial Peptides: A Promising Solution to the Rising Threat of Antibiotic Resistance

The demand for developing novel antimicrobial drugs has increased due to the rapid appearance and global spread of antibiotic resistance. Antimicrobial peptides (AMPs) offer distinct advantages over traditional antibiotics, such as broad-range efficacy, a delayed evolution of resistance, and the capacity to enhance human immunity. AMPs are being developed as potential medicines, and current computational and experimental tools aim to facilitate their preclinical and clinical development. Structural and functional constraints as well as a more stringent regulatory framework have impeded clinical translation of AMPs as possible therapeutic agents. Although around four thousand AMPs have been identified so far, there are some limitations of using these AMPs in clinical trials due to their safety in the host and sometimes limitations in the biosynthesis or chemical synthesis of some AMPs. Overcoming these obstacles may help to open a new era of AMPs to combat superbugs without using synthetic antibiotics. This review describes the classification, mechanisms of action and immune modulation, advantages, difficulties, and opportunities of using AMPs against multidrug-resistant pathogens and highlights the need and priorities for creating targeted development strategies that take into account the most cutting-edge tools currently available. It also describes the barriers to using these AMPs in clinical trials.

Antibacterial Activity of Phloretin Against Vibrio parahaemolyticus and Its Application in Seafood

Although phloretin is widely utilized in the food industry as an additive, its effects on foodborne pathogens remain insufficiently investigated. This study aimed to evaluate the antimicrobial properties of phloretin (PHL) against Vibrio parahaemolyticus (V. parahaemolyticus) and to elucidate the potential mechanisms of action. After PHL treatment, alterations in the cell morphology, cell microstructure, and intracellular contents of V. parahaemolyticus were assessed. Scanning electron microscopy revealed substantial damage to cell integrity, subsequent to PHL treatment. A notable reduction in intracellular components, including proteins, ATP, and DNA, was observed in samples treated with PHL. PHL was shown to inhibit the activities of ATPase, β-galactosidase, and respiratory chain dehydrogenase in V. parahaemolyticus. Furthermore, it was demonstrated to elevate the intracellular levels of reactive oxygen species and promote cell death. After being applied to sea bass, shrimp, and oysters, PHL effectively inactivated V. parahaemolyticus in these seafoods. These findings demonstrate that PHL has potential for application in seafood to control V. parahaemolyticus.

Perturbation of hyperthermia resistance in gastric cancer by hyperstimulation of autophagy using artemisinin-protected iron-oxide nanoparticles

In a bid to overcome hyperthermia resistance, a major obstacle in cancer treatment, this study explores manipulating autophagy, a cellular recycling mechanism, within the context of gastric cancer. We designed artemisinin-protected magnetic iron-oxide nanoparticles (ART-MNPs) to hyperactivate autophagy, potentially sensitizing cancer cells to hyperthermia. The synthesized ART-MNPs exhibited magnetic properties and the capability of raising the temperature by 7 °C at 580.3 kHz. Importantly, ART-MNPs displayed significant cytotoxicity against human gastric cancer cells (AGS), with an IC50 value of 1.9 μg mL-1, demonstrating synergistic effects compared to either MNPs or ART treatment alone (IC50 for MNPs is 9.7 μg mL-1 and for ART is 9.4 μg mL-1 respectively). Combination index studies further supported this synergy. Mechanistic analysis revealed a significant increase in autophagy level (13.58- and 15.08-fold increase compared to artemisinin and MNPs, respectively) upon ART-MNP treatment, suggesting that this hyperactivation is responsible for hyperthermia sensitization and minimized resistance (as evidenced by changes in viability compared to control under hyperthermic conditions). This work offers a promising strategy to modulate autophagy and overcome hyperthermia resistance, paving the way for developing hyperthermia as a standalone therapy for gastric cancer.

β-cyclodextrin inclusion complexes with short-chain phenolipids: An effective formulation for the dual sustained-release of phenolic compounds

The β-cyclodextrin and short-chain alkyl gallates (A-GAs), which are representative of phenolipids, such as butyl, propyl, ethyl, and methyl gallates, were chosen to form inclusion complexes by the use of the freeze-drying process. In the everted rat gut sac model, HPLC-UV analysis demonstrated that the released A-GAs from inclusion complexes were degraded to yield free gallic acid (GA) (sustained-release function 1). The small intestine membrane may be crossed by both the GA and the A-GAs. A-GAs may also undergo hydrolysis to provide GA (sustained-release function 2) following transmembrane transfer. Clearly, a helpful technique for the dual sustained-release of phenolic compounds is to produce β-cyclodextrin inclusion complexes with short-chain phenolipids. This will increase the bioactivities of phenolic compounds and prolong their in vivo residence length. Moreover, changing the carbon-chain length of these β-cyclodextrin inclusion complexes would readily modify the dual sustained-release behavior of the phenolic compounds. Thus, our work effectively established a theoretical foundation for the use of β-cyclodextrin inclusion complexes containing short-chain phenolipids as new source of functional food components to provide the body with phenolic compounds more efficiently.

Applicability of Redirecting Artemisinins for New Targets

Employing new therapeutic indications for drugs that are already approved for human use has obvious advantages, including reduced costs and timelines, because some routine steps of drug development and regulation are not required. This work concentrates on the redirection of artemisinins (ARTS) that already are approved for clinical use, or investigated, for malaria treatment. Several mechanisms of action are suggested for ARTS, among which only a few have been successfully examined in vivo, mainly the induction of oxidant stress and anti-inflammatory effects. Despite these seemingly contradictory effects, ARTS are proposed for repurposing in treatment of inflammatory disorders and diverse types of diseases caused by viral, bacterial, fungal, and parasitic infections. When pathogens are treated the expected outcome is diminution of the causative agents and/or their inflammatory damage. In general, repurposing ARTS is successful in only a very few cases, specifically when a valid mechanism can be targeted using an additional therapeutic agent and appropriate drug delivery. Investigation of repurposing should include optimization of drug combinations followed by examination in relevant cell lines, organoids, and animal models, before moving to clinical trials.

Cyclodextrin inclusion complexes improving antibacterial drug profiles: an update systematic review

Aim: The study aimed to review experimental models using cyclodextrins to improve antibacterial drugs' physicochemical characteristics and biological activities. Methods: The following terms and their combinations were used: cyclodextrins and antibacterial agents in title or abstract, and the total study search was conducted over a period up to October 2022. The review was carried out using PubMed, Scopus and Embase databases. A total of 1580 studies were identified, of which 27 articles were selected for discussion in this review. Results: The biological results revealed that the antibacterial effect of the inclusion complexes was extensively improved. Cyclodextrins can enhance the therapeutic effects of antibiotics already existing on the market, natural products and synthetic molecules. Conclusion: Overall, CDs as drug-delivery vehicles have been shown to improve antibiotics solubility, stability, and bioavailability, leading to enhanced antibacterial activity.

Dietary artemisinin boosts intestinal immunity and healthy in fat greenling (Hexagrammos otakii)

Introduction

Artemisinin (ART) is very common as a diet additive due to its immunoregulatory activities. Nonetheless, the immunoregulatory mechanism of ART in marine fish remains unknown. This study comprehensively examined the effects and explored the potential mechanism of ART ameliorating intestinal immune disease (IID) in fat greenlings (Hexagrammos otakii).

Methods and results

The targets of ART were screened using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Here, eight putative targets of ART were collected and identified with the Uniprot database, and 1419 IID-associated target proteins were filtered through the Drugbank, Genecards, OMIM, and PHARMGKB Databases. The results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways point out that ART may have immunoprotective effects by regulating cellular responses to stress, hypoxia, inflammation, and vascular endothelial growth factor stimulus through the hypoxia-inducible factor 1 (HIF-1) signaling pathway. The findings of molecular docking indicated that ART contains one active ingredient and three cross-targets, which showed a kind combination with hypoxia-inducible factor 1-alpha (HIF1-a), transcription factor p65 (RELA), and vascular endothelial growth factor A (VEGF-A), respectively. Furthermore, an ART feeding model was established to assess the ART's immunoprotect effect on the intestine of H.otakii in vivo. The D48 group showed smaller intestinal structural changes after being challenged by Edwardsiella tarda. The supplementation of ART to the diet improved total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and reduced the malondialdehyde (MDA) in intestine of H. otakii. The expression of transcription factor p65, HIF1-α, VEGF-A, cyclin D1, matrix metalloprotease 9 (MMP9), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) was decreased after dietary ART in the intestinal of H. otakii.

Discussion

The present results demonstrated that dietary ART improved antioxidants and immunity, optimized the intestinal structure, and increased resistance to E. tarda through the SOD2/nuclear-factor-kappa- B (NFkB)/HIF1-a/VEGF-A pathway in the intestinal tract of H.otakii. This study integrated pharmacological analysis and experimental validation and revealed the mechanism of ART on IID, which provides insight into the improvement of IID in H. otakii.

Molecular insights into artemisinin resistance in Plasmodium falciparum: An updated review

Malaria still poses a major burden on human health around the world, especially in endemic areas. Plasmodium resistance to several antimalarial drugs has been one of the major hindrances in control of malaria. Thus, the World Health Organization recommended artemisinin-based combination therapy (ACT) as a front-line treatment for malaria. The emergence of parasites resistant to artemisinin, along with resistant to ACT partner drugs, has led to ACT treatment failure. The artemisinin resistance is mostly related to the mutations in the propeller domain of the kelch13 (k13) gene that encodes protein Kelch13 (K13). The K13 protein has an important role in parasite reaction to oxidative stress. The most widely spread mutation in K13, with the highest degree of resistance, is a C580Y mutation. Other mutations, which are already identified as markers of artemisinin resistance, are R539T, I543T, and Y493H. The objective of this review is to provide current molecular insights into artemisinin resistance in Plasmodium falciparum. The trending use of artemisinin beyond its antimalarial effect is described. Immediate challenges and future research directions are discussed. Better understanding of the molecular mechanisms underlying artemisinin resistance will accelerate implementation of scientific findings to solve problems with malarial infection.

Noncovalent Host-Guest Complexes of Artemisinin with α-, β-, and γ- Cyclodextrin Examined by Structural Mass Spectrometry Strategies

Cyclodextrins (CDs) are a family of macrocyclic oligosaccharides with amphiphilic properties, which can improve the stability, solubility, and bioavailability of therapeutic compounds. There has been growing interest in the advancement of efficient and reliable analytical methods that assist with elucidating CD host-guest drug complexation. In this study, we investigate the noncovalent ion complexes formed between naturally occurring dextrins (αCD, βCD, γCD, and maltohexaose) with the poorly water-soluble antimalarial drug, artemisinin, using a combination of ion mobility-mass spectrometry (IM-MS), tandem MS/MS, and theoretical modeling approaches. This study aims to determine if the drug can complex within the core dextrin cavity forming an inclusion complex or nonspecifically bind to the periphery of the dextrins. We explore the use of group I alkali earth metal additives to promote the formation of various noncovalent gas-phase ion complexes with different drug/dextrin stoichiometries (1:1, 1:2, 1:3, 1:4, and 2:1). Broad IM-MS collision cross section (CCS) mapping (n > 300) and power-law regression analysis were used to confirm the stoichiometric assignments. The 1:1 drug:αCD and drug:βCD complexes exhibited strong preferences for Li+ and Na+ charge carriers, whereas drug:γCD complexes preferred forming adducts with the larger alkali metals, K⁺, Rb⁺, and Cs⁺. Although the ion-measured CCS increased with cation size for the unbound artemisinin and CDs, the 1:1 drug:dextrin complexes exhibit near-identical CCS values regardless of the cation, suggesting these are inclusion complexes. Tandem MS/MS survival yield curves of the [artemisinin:βCD + X]⁺ ion (X = H, Li, Na, K) showed a decreased stability of the ion complex with increasing cation size. Empirical CCS measurements of the [artemisinin:βCD + Li]⁺ ion correlated with predicted CCS values from the low-energy theoretical structures of the drug incorporated within the βCD cavity, providing further evidence that gas-phase inclusion complexes are formed in these experiments. Taken together, this work demonstrates the utility of combining analytical information from IM-MS, MS/MS, and computational approaches in interpreting the presence of gas-phase inclusion phenomena.

Formulation and Biopharmaceutical Evaluation of Capsules Containing Freeze-Dried Cranberry Fruit Powder

Cranberry fruits are an important source of anthocyanins and anthocyanidins. The aim of the present study was to investigate the effect of excipients on the solubility of cranberry anthocyanins and their dissolution kinetics as well as on the disintegration time of the capsules. Selected excipients (sodium carboxymethyl cellulose, beta-cyclodextrin and chitosan) were found to affect the solubility and release kinetics of anthocyanins in freeze-dried cranberry powder. Capsule formulations N1-N9 had a disintegration time of less than 10 min, and capsule formulation N10 containing 0.200 g of freeze-dried cranberry powder, 0.100 g of Prosolv (combination of microcrystalline cellulose and colloidal silicon dioxide), and 0.100 g of chitosan had a capsule disintegration time of over 30 min. The total amount of anthocyanins released into the acceptor medium ranged from 1.26 ± 0.06 mg to 1.56 ± 0.03 mg. Capsule dissolution test data showed that the time to release into the acceptor medium was statistically significantly longer for the chitosan-containing capsule formulations compared to the control capsules (p < 0.05). Freeze-dried cranberry fruit powder is a potential source of anthocyanin-rich dietary supplements, and the choice of excipient chitosan could be a suitable solution in capsule formulations providing greater anthocyanin stability and modified release in the gastrointestinal tract.

Regulation of Staphylococcus aureus Virulence and Application of Nanotherapeutics to Eradicate S. aureus Infection

Staphylococcus aureus is a versatile pathogen known to cause hospital- and community-acquired, foodborne, and zoonotic infections. The clinical infections by S. aureus cause an increase in morbidity and mortality rates and treatment costs, aggravated by the emergence of drug-resistant strains. As a multi-faceted pathogen, it is imperative to consolidate the knowledge on its pathogenesis, including the mechanisms of virulence regulation, development of antimicrobial resistance, and biofilm formation, to make it amenable to different treatment strategies. Nanomaterials provide a suitable platform to address this challenge, with the potential to control intracellular parasitism and multidrug resistance where conventional therapies show limited efficacy. In a nutshell, the first part of this review focuses on the impact of S. aureus on human health and the role of virulence factors and biofilms during pathogenesis. The second part discusses the large diversity of nanoparticles and their applications in controlling S. aureus infections, including combination with antibiotics and phytochemicals and the incorporation of antimicrobial coatings for biomaterials. Finally, the limitations and prospects using nanomaterials are highlighted, aiming to foster the development of novel nanotechnology-driven therapies against multidrug-resistant S. aureus.

Milk-Derived Antimicrobial Peptides: Overview, Applications, and Future Perspectives

The growing consumer awareness towards healthy and safe food has reformed food processing strategies. Nowadays, food processors are aiming at natural, effective, safe, and low-cost substitutes for enhancing the shelf life of food products. Milk, besides being a rich source of nutrition for infants and adults, serves as a readily available source of precious functional peptides. Due to the existence of high genetic variability in milk proteins, there is a great possibility to get bioactive peptides with varied properties. Among other bioactive agents, milk-originated antimicrobial peptides (AMPs) are gaining interest as attractive and safe additive conferring extended shelf life to minimally processed foods. These peptides display broad-spectrum antagonistic activity against bacteria, fungi, viruses, and protozoans. Microbial proteolytic activity, extracellular peptidases, food-grade enzymes, and recombinant DNA technology application are among few strategies to tailor specific peptides from milk and enhance their production. These bioprotective agents have a promising future in addressing the global concern of food safety along with the possibility to be incorporated into the food matrix without compromising overall consumer acceptance. Additionally, in conformity to the current consumer demands, these AMPs also possess functional properties needed for value addition. This review attempts to present the basic properties, synthesis approaches, action mechanism, current status, and prospects of antimicrobial peptide application in food, dairy, and pharma industry along with their role in ensuring the safety and health of consumers.

Supplementing artemisinin positively influences growth, antioxidant capacity, immune response, gut health and disease resistance against Vibrio parahaemolyticus in Litopenaeus vannamei fed cottonseed protein concentrate meal diets

Artemisinin (ART) is a kind of Chinese herbal medicine worth exploring, which obtains various physiological activities. In order to study the prebiotic effect of ART on Litopenaeus vannamei fed cottonseed protein concentrate meal diets, six groups of isonitrogenous and isolipid diets were prepared (including the fish meal control group, FM; cottonseed protein concentrate replacing 30% fishmeal protein and supplementing ART groups: ART0, ART0.3, ART0.6, ART0.9, and ART1.2). The feeding trials was lasted for 56 days. The results showed that the final body weight, weight gain and specific growth rate of the ART0.6 group were the highest, yet the feed coefficient rate of the ART0.6 group was the lowest significantly (P < 0.05). There was no significant difference in survival rate among treatments (P > 0.05). In serum, the content of malondialdehyde in ART0 group was the highest (P < 0.05); the activities of superoxide dismutase, catalase, phenol oxidase and lysozyme increased firstly and then decreased among the ARTs groups (P < 0.05). The activities of intestinal digestive enzymes (including the trypsin, lipase and amylase) showed an upward trend among the ARTs groups (P < 0.05). The histological sections showed that the intestinal muscle thickness, fold height and fold width in the FM group were significantly better than those in the ART0 group; while the mentioned above morphological indexes in the ART0 group were significantly lowest among the ARTs groups (P < 0.05). Sequencing of intestinal microbiota suggested that the microbial richness indexes firstly increased and then decreased (P < 0.05); the bacterial community structure of each treatment group was almost close; the relative abundance of pathogenic bacteria decreased significantly (P < 0.05), such as the Proteobacteria and Cyanobacteria at phylum level, besides the Vibrio and Candidatus Bacilloplasma at genus level. In intestinal tissue, the relative expression levels of TOLL1, TRAF6 and Pehaeidih3 showed up-regulated trends, while the expression of Crustin and LZM firstly up-regulated and then down-regulated (P < 0.05). The challenge experiment suggested that the cumulative mortality of FM group was significantly lower than that of ART0 group; besides the cumulative mortality firstly increased and then decreased between the ARTs groups (P < 0.05). In conclusion, the dietary supplementation of ART can improve the growth, antioxidant capacity, immune response, gut health and disease resistance of the shrimp. To be considered as a dietary immune enhancer, the recommended supplementation level of ART in shrimp's cottonseed protein concentrate meal diets is 0.43%.

Ternary system of sultamicillin tosylate with hydroxypropyl-β-cyclodextrin and L-arginine: susceptibility against methicillin-resistant Staphylococcus aureus

Aim: This study investigated the effect of complex formation between sultamicillin tosylate (ST), hydroxypropyl-β cyclodextrin (HP-βCD) and L-arginine (ARG). Materials & methods: The kneading method was used to prepare the complexes, which were then characterized using SEM, DSC, FT-IR, HPLC, saturation solubility and dissolution studies. The complexes' antibacterial activity against MRSA (ATCC^®-43300TM) was evaluated using ZOI and MIC. Results: Solubility was enhanced in the binary and ternary complexes compared with ST (p < 0.001). MIC and ZOI showed that both complexes have increased antibacterial activity compared with ST (p < 0.001) against MRSA. Conclusion: As a result, the inclusion complex of ST with HP-βCD and ARG can be used to improve the physicochemical properties of ST while also improving antibacterial efficacy against MRSA infections.

Antimicrobial Effect of Epigallocatechin Gallate Against Shewanella putrefaciens ATCC 8071: A Study Based on Cell Membrane and Biofilm

The study was to evaluate the antimicrobial impacts and biofilm influences on epigallocatechin gallate (EGCG) against Shewanella putrefaciens ATCC 8071. The minimum inhibitory concentration (MIC) of EGCG on S. putrefaciens was 160 μg mL^-1. The growth curve exhibited that EGCG had a good antimicrobial activity. EGCG caused damages to the bacterial cell wall and membrane based the intracellular component leakage and cell viability analysis. The damage to the membrane integrity by EGCG has been confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM shows deformation of shape, TEM shows cell membrane and wall damage, and the leakage of cytoplasmic material. The treatment with EGCG at 0.25× and 0.5× MIC resulted in decreased motility and elevated levels of oxidative stress, leading to an increase in biofilm formation. These results demonstrated that EGCG may be used as a natural preservative to reduce S. putrefaciens in fish during cold storage.

Preparation and Characterisation of a Cyclodextrin-Complexed Mānuka Honey Microemulsion for Eyelid Application

Honey has been widely purported as a natural remedy due to its antimicrobial and anti-inflammatory effects. In recent years, several studies have suggested that the considerably high methylglyoxal (MGO) concentration in Mānuka honey (MH) makes it particularly effective to manage bacterial overload, such as that observed in blepharitis. However, the poor solubility, high viscosity, and osmolarity of aqueous honey solutions, especially at the high MGO concentrations studied in the literature, render the formulation of an acceptable dosage form for topical application to the eyelids challenging. Here, the antibacterial properties of raw MH and alpha-cyclodextrin (α-CD)-complexed MH were evaluated at relatively low MGO concentrations, and a liquid crystalline-forming microemulsion containing α-CD-complexed MH was formulated. After determining pH and osmolarity, ocular tolerability was assessed using human primary corneal epithelial cells and chorioallantoic membranes, while the antibacterial efficacy was further evaluated in vitro. The α-CD–MH complex had significantly greater antibacterial activity against Staphylococcus aureus than either constituent alone, which was evident even when formulated as a microemulsion. Moreover, the final formulation had a physiologically acceptable pH and osmolarity for eyelid application and was well-tolerated when diluted 1:10 with artificial tear fluid, as expected to be the case after accidental exposure to the ocular surface in the clinical setting. Thus, a safe and efficient MH dosage form was developed for topical application to the eyelids, which can potentially be used to support optimal eyelid health in the management of blepharitis.

Mechanism and effects of artesunate on the liver function of rats with type 1 diabetic periodontitis

Periodontitis is an inflammatory disease of the gums. Periodontitis in patients with diabetes can aggravate insulin resistance, but its molecular and biological mechanism remains unclear. This study aimed to explore the effects of diabetic periodontitis on liver function and determine the mechanism by which artesunate improves liver function. Rats with streptozotocin-induced diabetes were divided into five groups, i.e., normal control group (NC group), diabetic periodontitis group (DM+PD group), artesunate intervention group (ART group), insulin intervention group (INS group), and combined medication intervention group (ART+INS group). Drug interventions were then administered to the rats in each group as follows: 50 mg/kg artesunate to the ART group, 6 U/kg insulin to the INS group, and 50 mg/kg artesunate + 6 U/kg insulin to the ART+INS group. Blood samples, liver tissues, and the maxillary alveolar bone were collected post-sacrifice. ART was found to significantly ameliorate hyperglycemia, blood lipid levels, and liver function. The levels of inflammatory factors reduced; the effect was more pronounced in the ART+INS group. Artesunate presumably inhibits the TLR4/NF-κB signaling pathway and expression of downstream inflammatory factors, thereby exerting a protective effect on diabetes-related liver function. This offers a fresh approach to treat diabetes mellitus.

Complexation of phytochemicals with cyclodextrins and their derivatives- an update

Bioactive phytochemicals from natural source have gained tremendous interest over several decades due to their wide and diverse therapeutic activities playing key role as functional food supplements, pharmaceutical and nutraceutical products. Nevertheless, their application as therapeutically active moieties and formulation into novel drug delivery systems are hindered due to major drawbacks such as poor solubility, bioavailability and dissolution rate and instability contributing to reduction in bioactivity. These drawbacks can be effectively overcome by their complexation with different cyclodextrins. Present article discusses complexation of phytochemicals varying from flavonoids, phenolics, triterpenes, and tropolone with different natural and synthetic cyclodextrins. Moreover, the article summarizes complexation methods, complexation efficiency, stability, stability constants and enhancement in rate and extent of dissolution, bioavailability, solubility, in vivo and in vitro activities of reported complexed phytochemicals. Additionally, the article presents update of published patent details comprising of complexed phytochemicals of therapeutic significance. Thus, phytochemical cyclodextrin complexes have tremendous potential for transformation into drug delivery systems as substantiated by significant outcome of research findings.

The Interference Mechanism of Basil Essential Oil on the Cell Membrane Barrier and Respiratory Metabolism of Listeria monocytogenes

In order to prevent food-borne diseases caused by Listeria monocytogenes (L. monocytogenes) safely and effectively, plant essential oils that have no toxic side effects and are not prone to drug resistance have become the focus of research. This article takes basil (Ocimum basilicum L.) essential oil (BEO) as the research object and explores its antibacterial mechanism against L. monocytogenes. The site of action was preliminarily determined to provide a theoretical basis for the development of natural antibacterial agents. The results show that BEO has good antibacterial activity against L. monocytogenes. After 8 h of treatment with BEO (1 mg/ml), the number of remaining bacteria reached an undetectable level. Combining spectroscopic analysis techniques (Raman, UV, and fluorescence spectroscopy) and fluorescence microscopy imaging techniques, it was found that BEO increased the disorder of the hydrocarbyl chain of phospholipid tail, which in turn led to increased cell membrane permeability, thereby causing the leakage of intracellular proteins and DNA. Meanwhile, respiratory metabolism experiments showed that BEO inhibited the EMP pathway by inhibiting the activity of key enzymes. From the molecular docking results, this inhibition may be attributed to the hydrophobic interaction between α-bergamotene and the amino acid residues of phosphofructokinase (PFK) and pyruvate kinase (PK). In addition, BEO can also cause oxidative stress, and reactive oxygen species (ROS) may also be related to the damage of cell membranes and enzymes related to respiratory metabolism.

Advances in Nanostructures for Antimicrobial Therapy

Microbial infections caused by a variety of drug-resistant microorganisms are more common, but there are fewer and fewer approved new antimicrobial chemotherapeutics for systemic administration capable of acting against these resistant infectious pathogens. Formulation innovations of existing drugs are gaining prominence, while the application of nanotechnologies is a useful alternative for improving/increasing the effect of existing antimicrobial drugs. Nanomaterials represent one of the possible strategies to address this unfortunate situation. This review aims to summarize the most current results of nanoformulations of antibiotics and antibacterial active nanomaterials. Nanoformulations of antimicrobial peptides, synergistic combinations of antimicrobial-active agents with nitric oxide donors or combinations of small organic molecules or polymers with metals, metal oxides or metalloids are discussed as well. The mechanisms of actions of selected nanoformulations, including systems with magnetic, photothermal or photodynamic effects, are briefly described.

Improved art bioactivity by encapsulation within cyclodextrin carboxylate

Artemisinin (Art) is a natural sesquiterpene lactone that is claimed to exhibit various bioactivities. The poor solubility of Art in both water and oil hinders its application in formulations intended for oral administration. In this study, we investigated the potential of forming a host-guest complex between Art and succinic acid modified cyclodextrin (SACD) to improve its solubility characteristics. Art-SACD inclusion complexes (2:1 M ratio) were successfully formed in water, which was attributed to the relatively large cavity size of SACD, as well as the intermolecular interactions between the Art and succinic acid branches in the cavity. The thermal stability of the Art was retained after incorporation into the Art-SACD complexes, which may be useful for applications such as pasteurization or cooking. The encapsulated Art showed antibacterial activity against both Gram-positive and Gram-negative bacteria. Such encapsulation technology allows Art to be introduced into oral delivery systems in a bioactive form.

Enhanced antibacterial efficacy and mechanism of octyl gallate/beta-cyclodextrins against Pseudomonas fluorescens and Vibrio parahaemolyticus and incorporated electrospun nanofibers for Chinese giant salamander fillets preservation

A series of alkyl gallates were evaluated for the antibacterial activity against two common Gram-negative foodborne bacteria (Pseudomonas fluorescens and Vibrio parahaemolyticus) associated with seafood. The length of the alkyl chain plays a pivotal role in eliciting their antibacterial activities and octyl gallate (OG) exerted an excellent inhibitory efficacy. To extend the aqueous solubility, stability, and bactericidal properties of octyl gallate (OG), an inclusion complex between OG and β-cyclodextrin (βCD), OG/βCD, was prepared and identified with various methods including X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the enhanced inhibitory effect and potential antibacterial mechanism of OG/βCD against two Gram-negative and Gram-positive foodborne bacteria were comprehensively investigated. The results show that OG/βCD could function against bacteria through effectively damaging the membrane, permeating into cells, and then disturbing the activity of the respiratory electron transport chain to cause the production of high-level intracellular hydroxyl radicals. Moreover, the reinforced OG/βCD-incorporated polylactic acid (PLA) nanofibers were fabricated using the electrospinning technique as food packaging to extend the Chinese giant salamander fillet's shelf life at 4 °C. This research highlights the antibacterial effectiveness of OG/βCD in aqueous media, which can be used as a safe multi-functionalized food additive combined with the benefits of electrospun nanofibers to extend the Chinese giant salamander fillets shelf life by 15 d at 4 °C.

Management of life-threatening staphylococcal septic shock in a breastfeeding woman with breast abscess: A case report

Introduction and importance

Breast abscess is a common problem in breastfeeding women. However, septic shock secondary to methicillin resistant Staphylococcus aureus (MRSA) from breast abscess is very rare. Successful management of this condition in our center may provide experience of treatment for similar patients.

Case presentation

A 20-year-old breastfeeding woman with breast abscess was transferred to our center. General condition of the patient deteriorated rapidly to life-threatening septic shock. Culture of pus later demonstrated MRSA infection, with vancomycin susceptibility. Several measures were emergently implemented, including removal of necrotic tissue, continuous catheter irrigation and drainage, intravenous infusion of vancomycin, pumping norepinephrine, fluid resuscitation and transfusion of plasma. The patient was cured and discharged after 10 day's treatment.

Clinical discussion

Life-threatening septic shock secondary to MRSA in breastfeeding women with breast abscess is very rare. Nevertheless, clinicians should remain vigilant to early symptoms and signs of septic shock. Catheter irrigation and drainage, vancomycin and fluid resuscitation are essential for septic shock in lactational breast abscess.

Conclusions

We highlight the importance of the diagnosis and management of life-threatening septic shock secondary to MRSA in breast abscess to help us further understand this rare and fatal disease.

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Life-threatening septic shock secondary to MRSA in a breastfeeding woman with breast abscess is very rare.

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We should pay more attention to the early symptoms and signs of septic shock.

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Catheter irrigation and drainage, vancomycin and fluid resuscitation are essential for septic shock in breast abscess.

Artemisinin displays bactericidal activity via copper-mediated DNA damage

Artemisinin (ARS) and its semi-synthetic derivatives are effective drugs to treat malaria and possess multiple therapeutic activities based on their endoperoxide bridge. Here, we showed that ARS displayed antibacterial efficacy in Drosophila systemic infections caused by bacterial pathogens but killed only Vibrio cholerae (VC) in vitro, involving reactive oxygen species (ROS) generation and/or DNA damage. This selective antibacterial activity of ARS was attributed to the higher intracellular copper levels in VC, in that the antibacterial activity was observed in vitro upon addition of cuprous ions even against other bacteria and was compromised by the copper-specific chelators neocuproine (NC) and triethylenetetramine (TETA) in vitro and in vivo. We suggest that copper can enhance or reinforce the therapeutic activities of ARS to be repurposed as an antibacterial drug for the treatment of bacterial infections.

Plant-microbial interaction: The mechanism and the application of microbial elicitor induced secondary metabolites biosynthesis in medicinal plants

Plants and microbes interact with each other via different chemical signaling pathways. At the risophere level, the microbes can secrete molecules, called elicitors, which act on their receptors located in plant cells. The so-called elicitor molecules as well as their actions differ according to the mcirobes and induce different bilogical responses in plants such as the synthesis of secondary metabolites. Microbial compounds induced phenotype changes in plants are known as elicitors and signaling pathways which integrate elicitor's signals in plants are called elicitation. In this review, the impact of microbial elicitors on the synthesis and the secretion of secondary metabolites in plants was highlighted. Moreover, biological properties of these bioactive compounds were also highlighted and discussed. Indeed, several bacteria, fungi, and viruses release elicitors which bind to plant cell receptors and mediate signaling pathways involved in secondary metabolites synthesis. Different phytochemical classes such as terpenoids, phenolic acids and flavonoids were synthesized and/or increased in medicinal plants via the action of microbial elicitors. Moreover, these compounds compounds exhibit numerous biological activities and can therefore be explored in drugs discovery.

Antibacterial plant compounds, extracts and essential oils: An updated review on their effects and putative mechanisms of action

BACKGROUND

Antibiotic-resistant bacteria pose a global health threat. Traditional antibiotics can lose their effectiveness, and the development of novel effective antimicrobials has become a priority in recent years. In this area, plants represent an invaluable source of antimicrobial compounds with vast therapeutic potential.

PURPOSE

To review the full possible spectrum of plant antimicrobial agents (plant compounds, extracts and essential oils) discovered from 2016 to 2021 and their potential to decrease bacterial resistance. Their activities against bacteria, with special emphasis on multidrug resistant bacteria, mechanisms of action, possible combinations with traditional antibiotics, roles in current medicine and future perspectives are discussed.

METHODS

Studies focusing on the antimicrobial activity of compounds of plant origin and their mechanism of action against bacteria were identified and summarized, including contributions from January 2016 until January 2021. Articles were extracted from the Medline database using PubMed search engine with relevant keywords and operators.

RESULTS

The search yielded 11,689 articles from 149 countries, of which 101 articles were included in this review. Reports from 41 phytochemicals belonging to 20 families were included. Reports from plant extracts and essential oils from 39 plant species belonging to 17 families were also included. Polyphenols and terpenes were the most active phytochemicals studied, either alone or as a part of plant extracts or essential oils. Plasma membrane disruption was the most common mechanism of antimicrobial action. Number and position of phenolic hydroxyl groups, double bonds, delocalized electrons and conjugation with sugars in the case of flavonoids seemed to be crucial for antimicrobial capacity. Combinations of phytochemicals with beta-lactam antibiotics were the most studied, and the inhibition of efflux pumps was the most common synergistic mechanism.

CONCLUSION

In recent years, terpenes, flavones, flavonols and some alkaloids and phenylpropanoids, either isolated or as a part of extracts, have shown promising antimicrobial activity, being membrane disruption their most common mechanism. However, their utilization as appropriate antimicrobials need to be boosted by means of new omics technologies and network pharmacology to find the most effective combinations among them or in combination with antibiotics.

Formulation of pH responsive multilamellar vesicles for targeted delivery of hydrophilic antibiotics

Fight against antimicrobial resistance calls for innovative strategies that can target infection sites and enhance activity of antibiotics. Herein is a pH responsive multilamellar vesicles (MLVs) for targeting bacterial infection sites. The vancomycin (VCM) loaded MLVs had 62.25 ± 8.7 nm, 0.15 ± 0.01 and -5.55 ± 2.76 mV size, PDI and zeta potential, respectively at pH 7.4. The MLVs had a negative ZP at pH 7.4 that switched to a positive charge and faster release of the drug at acidic pH. The encapsulation efficiency was found to be 46.34 ± 3.88 %. In silico studies of the lipids, interaction suggested an energetically stable system. Studies to determine the minimum inhibitory concentration studies (MIC) showed the MLVs had 2-times and 8-times MIC against Staphylococcus aureus (SA) and Methicillin resistance SA respectively at physiological pH. While at pH 6.0 there was 8 times reduction in MICs for the formulation against SA and MRSA in comparison to the bare drug. Fluorescence-activated Cell Sorting (FACS) studies demonstrated that even with 8-times lower MIC, MLVs had a similar elimination ability of MRSA cells when compared to the bare drug. Fluorescence microscopy showed MLVs had the ability to clear biofilms while the bare drug could not. Mice skin infection models studies showed that the colony finding units (CFUs) of MRSA recovered from groups treated with MLVs was 4,050 and 525-fold lower than the untreated and bare VCM treated groups, respectively. This study demonstrated pH-responsive multilamellar vesicles as effective system for targeting and enhancing antibacterial agents.

Biomimetic pH/lipase dual responsive vitamin-based solid lipid nanoparticles for on-demand delivery of vancomycin

In this study, ascorbyl tocopherol succinate (ATS) was designed, synthesized and characterized via FT-IR, HR-MS, H¹ NMR and C¹³ NMR, to simultaneously confer biomimetic and dual responsive properties of an antibiotic nanosystem to enhance their antibacterial efficacy and reduce antimicrobial resistance. Therefore, an in silico-aided design (to mimic the natural substrate of bacterial lipase) was employed to demonstrate the binding potential of ATS to lipase (-32.93 kcal/mol binding free energy (ΔG_bind) and bacterial efflux pumps blocking potential (NorA ΔG_bind: -37.10 kcal/mol, NorB ΔG_bind: -34.46 kcal/mol). ATS bound stronger to lipase than the natural substrate (35 times lower Kd value). The vancomycin loaded solid lipid nanoparticles (VM-ATS-SLN) had a hydrodynamic diameter, zeta potential, polydispersity index and entrapment efficiency of 106.9 ± 1.4 nm, -16.5 ± 0.93 mV, 0.11 ± 0.012 and 61.9 ± 1.31%, respectively. In vitro biocompatibility studies revealed VM-ATS-SLN biosafety and non-haemolytic activity. Significant enhancement in VM release was achieved in response to acidified pH and lipase enzyme, compared to controls. VM-ATS-SLN showed enhanced sustained in vitro antibacterial activity for 5 days, 2-fold greater MRSA biofilm growth inhibition and 3.44-fold reduction in bacterial burden in skin infected mice model compared to bare VM. Therefore, ATS shows potential as a novel multifunctional adjuvant for effective and targeted delivery of antibiotics.

Artemisinin elevates ergosterol levels of Candida albicans to synergise with amphotericin B against oral candidiasis

Oral candidiasis, especially caused by Candida albicans, is the most common fungal infection of the oral cavity. The increase in drug resistance and lack of new antifungal agents call for new strategies of antifungal treatment. This study repurposed artemisinin (Art) as a potentiator to the polyene amphotericin B (AmB) and characterised their synergistic mechanism against C. albicans and oral candidiasis. The synergistic antifungal activity between Art and AmB was identified by the checkerboard and recovery plate assays according to the fractional inhibitory concentration index (FICI). Art showed no antifungal activity even at >200 mg/L. However, it significantly reduced AmB dosages against the wild-type strain and 75 clinical isolates of C. albicans (FICI ≤ 0.5). Art significantly upregulated expression of genes from the ergosterol biosynthesis pathway (ERG1, ERG3, ERG9 and ERG11), as shown by RT-qPCR, and elevated the ergosterol content of Candida cells. Increased ergosterol content significantly enhanced binding between fungal cells and the polyene agent, resulting in sensitisation of C. albicans to AmB. Drug combinations of Art and AmB showed synergistic activity against oral mucosal infection in vivo by reducing the epithelial infection area, fungal burden and inflammatory infiltrates in murine oropharyngeal candidiasis. These findings indicate a novel synergistic antifungal drug combination and a new Art mechanism of action, suggesting that drug repurposing is a clinically practical means of antifungal drug development and treatment of oral candidiasis.

Emerging resistance mechanisms for 4 types of common anti-MRSA antibiotics in Staphylococcus aureus: A comprehensive review

Staphylococcus aureus is one of the leading hospital-associated and community-associated pathogens, which has caused a global public health concern. The emergence of methicillin-resistant S. aureus (MRSA) along with the widespread use of different classes of antibiotics has become a significant therapeutic challenge. Antibiotic resistance is a disturbing problem that poses a threat to humans. Treatment options for S. aureus resistant to β-lactam antibiotics include glycopeptide antibiotic, cyclic lipopeptide antibiotic, cephalosporins and oxazolidinone antibiotic. The most representative types of these antibiotics are vancomycin, daptomycin, ceftaroline and linezolid. The frequent use of the first-line drug vancomycin for MRSA treatment has increased the number of resistant strains, namely vancomycin intermediate resistant S. aureus (VISA) and vancomycin resistant S. aureus (VRSA). A systematic literature review of relevant published studies in PubMed before 2020 was conducted. In recent years, there have been some reports on the relevant resistant mechanisms of vancomycin, daptomycin, ceftaroline and linezolid. In this review, we have summarized the antibiotic molecular modes of action and different gene mutants at the whole-genome level, which will aid in further development on new drugs for effective MRSA treatment based on describing different resistance mechanisms of classic antibiotics.

Role of Artesunate on cardiovascular complications in rats with type 1 diabetes mellitus

BACKGROUND

The present study aimed to evaluate the effect of artesunate (ART) on the reduction of cardiovascular complications in a type 1 diabetes model and to investigate the associated mechanism based on the receptor for advanced glycation end-product (RAGE)/NF-κB signaling pathway.

METHODS

A total of 40 male Sprague-Dawley rats were randomly divided into five groups: The healthy, diabetic, 50 mg/kg ART (ig) treatment diabetic, 100 mg/kg ART (ig) treatment diabetic, and 6 U/kg insulin (iH) treatment diabetic groups. The treatment lasted 4 weeks after the diabetic model was established via intraperitoneal injection of streptozotocin. Blood samples were collected, and cardiovascular tissues were harvested and processed to measure various parameters after the animals were sacrificed. The myocardium and aortic arch tissues were evaluated using hematoxylin-eosin and Masson staining. Expression levels of RAGE, NF-κB, matrix metalloproteinase MMP9, MMP1 and CD68 in the myocardium and aortic arch tissues were detected using immunohistochemistry, and mRNA expression was determined using reverse transcription-quantitative PCR.

RESULTS

The results of the present study demonstrated that ART treatment may restrain diabetes-induced cardiovascular complications by maintaining heart and body weight while reducing blood glucose, as well as regulating blood lipid indicators to normal level (P < 0.05). The expression levels of NF-κB, CD68, MMP1, MMP9 and RAGE were decreased in the ART-treated diabetic rats (P < 0.05).

CONCLUSIONS

ART treatment may have a protective role against diabetes-associated cardiovascular complications in diabetic rats by inhibiting the expression of proteins in the RAGE/NF-κB signaling pathway and downstream inflammatory factors. High concentrations of ART had a hypoglycemic effect, while a low concentration of ART prevented cardiovascular complications.

Controlled-release casein/cinnamon essential oil nanospheres for the inactivation of Campylobacter jejuni in duck

Campylobacter jejuni (C. jejuni) is one of the most common foodborne pathogens that cause human sickness mostly through the poultry food chain. Cinnamon essential oil (CEO) has excellent antibacterial ability against C. jejuni growth. This study investigated the antibacterial mechanism of CEO against C. jejuni primarily through metabolism, energy metabolism of essential enzymes (AKPase, β-galactosidase, and ATPase), and respiration metabolism. Results showed that the hexose monophosphate pathway (HMP) was inhibited, and that the enzyme activity of G₆DPH substantially decreased upon treatment with CEO. Analysis of the effect of CEO on the expression of toxic genes was performed by the real-time PCR (RT-PCR). The expression levels of the toxic genes cadF, ciaB, fliA, and racR under CEO treatment were determined. Casein/CEO nanospheres were further prepared for the effective inhibition of C. jejuni and characterized by particle-size distribution, zeta-potential distribution, fluorescence, TEM, and GC-MS methods. Finally, the efficiency of CEO and casein/CEO nanospheres in terms of antibacterial activity against C. jejuni was verified. The casein/CEO nanospheres displayed high antibacterial activity on duck samples. The population of the test group decreased from 4.30 logCFU/g to 0.86 logCFU/g and 4.30 logCFU/g to 2.46 logCFU/g at 4 °C and at 25 °C for C. jejuni, respectively. Sensory evaluation and texture analysis were also conducted on various duck samples.

Exploration of artemisinin derivatives and synthetic peroxides in antimalarial drug discovery research

Malaria is a life-threatening infectious disease caused by protozoal parasites belonging to the genus Plasmodium. It caused an estimated 405,000 deaths and 228 million malaria cases globally in 2018 as per the World Malaria Report released by World Health Organization (WHO) in 2019. Artemisinin (ART), a "Nobel medicine" and its derivatives have proven potential application in antimalarial drug discovery programs. In this review, antimalarial activity of the most active artemisinin derivatives modified at C-10/C-11/C-16/C-6 positions and synthetic peroxides (endoperoxides, 1,2,4-trioxolanes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes) are systematically summarized. The developmental trend of ART derivatives, and cyclic peroxides along with their antimalarial activity and how the activity is affected by structural variations on different sites of the compounds are discussed. This compilation would be very useful towards scaffold hopping aimed at avoiding the unnecessary complexity in cyclic peroxides, and ultimately act as a handy resource for the development of potential chemotherapeutics against Plasmodium species.

Research Advances on Health Effects of Edible Artemisia Species and Some Sesquiterpene Lactones Constituents

The genus Artemisia, often known collectively as "wormwood", has aroused great interest in the scientific community, pharmaceutical and food industries, generating many studies on the most varied aspects of these plants. In this review, the most recent evidence on health effects of edible Artemisia species and some of its constituents are presented and discussed, based on studies published until 2020, available in the Scopus, Web of Sciences and PubMed databases, related to food applications, nutritional and sesquiterpene lactones composition, and their therapeutic effects supported by in vivo and clinical studies. The analysis of more than 300 selected articles highlights the beneficial effect on health and the high clinical relevance of several Artemisia species besides some sesquiterpene lactones constituents and their derivatives. From an integrated perspective, as it includes therapeutic and nutritional properties, without ignoring some adverse effects described in the literature, this review shows the great potential of Artemisia plants and some of their constituents as dietary supplements, functional foods and as the source of new, more efficient, and safe medicines. Despite all the benefits demonstrated, some gaps need to be filled, mainly related to the use of raw Artemisia extracts, such as its standardization and clinical trials on adverse effects and its health care efficacy.

Investigation on the biofilm eradication potential of selected medicinal plants against methicillin-resistant Staphylococcus aureus

Biofilms are multi-species bacterial communities with complex structures that create antibiotic resistance, cause life-threatening infections, thereby considerable economic loss; needed new approaches. Medicinal plants are focused as new alternatives for their therapeutic and antimicrobial effects. Our present study, Azadirachta indica, Moringa oleifera, Murraya koenigii, and Psidium guajava extracts were investigated against MRSA. The preliminary antimicrobial study showed pet. ether extract of A. indica and ethanolic extract of P. guajava showed a MIC value of 125 μg/mL and MBC value of 500 μg/mL. These extracts showed biofilm inhibition in the range of 60.0-83.9 % and did not possess any hemolytic activity to the human erythrocytes. The plant species investigated in this study had different degrees of antibiofilm activity against MRSA. However, we suggest that A. indica and P. guajava are promising candidates and further investigation is needed to isolate the antimicrobial compounds for the management of MRSA and its mechanism of activity.

Elucidating Antibacterial Activity and Mechanism of Daphnetin against Pseudomonas fluorescens and Shewanella putrefaciens

In this research, the antibacterial activity and mechanism of daphnetin against Pseudomonas fluorescens and Shewanella putrefaciens were evaluated. The minimum inhibitory concentration (MIC) of daphnetin on P. fluorescens and S. putrefaciens was 0.16 and 0.08 mg·mL−1, respectively. The growth curve test also showed that daphnetin had a good antibacterial effect. The results of intracellular component leakage and cell viability analysis illustrated that daphnetin destroyed the morphology of the cell membrane. According to scanning electron microscope and transmission electron microscope observations, the treated bacterial cells displayed obvious morphological and ultrastructural changes in the cell membrane of the two tested strains, whichconfirmed daphnetin’s damage to the integrity of the cell membrane. The findings indicated that daphnetin mainly exerted its antibacterial effect by destroying the membrane and suggested that it had good potential to be as a natural food preservative.

Synergistic Therapies as a Promising Option for the Treatment of Antibiotic-Resistant Helicobacter pylori

Helicobacter pylori is a Gram-negative bacterium responsible for the development of gastric diseases. The issue of spreading antibiotic resistance of H. pylori and its limited therapeutic options is an important topic in modern gastroenterology. This phenomenon is greatly associated with a very narrow range of antibiotics used in standard therapies and, as a consequence, an alarmingly high detection of multidrug-resistant H. pylori strains. For this reason, scientists are increasingly focused on the search for new substances that will not only exhibit antibacterial effect against H. pylori, but also potentiate the activity of antibiotics. The aim of the current review is to present scientific reports showing newly discovered or repurposed compounds with an ability to enhance the antimicrobial activity of classically used antibiotics against H. pylori. To gain a broader context in their future application in therapies of H. pylori infections, their antimicrobial properties, such as minimal inhibitory concentrations and minimal bactericidal concentrations, dose- and time-dependent mode of action, and, if characterized, anti-biofilm and/or in vivo activity are further described. The authors of this review hope that this article will encourage the scientific community to expand research on the important issue of synergistic therapies in the context of combating H. pylori infections.

Encapsulation of essential oil components with methyl-β-cyclodextrin using ultrasonication: Solubility, characterization, DPPH and antibacterial assay

Essential oils derived from medicinal plants are prosperous sources of active components having high biological potential. Cuminaldehye and isoeugenol, are hydrophobic essential oil components (EOC), are showing drastic limitations in their applications by low water solubility and the respective volatility. Methyl-β-cyclodextrin inclusion complexes (MβCD-ICs) were prepared in aqueous solution and in solid state with the EOC via the ultrasonication method, an energy saving, high efficiency and eco-friend technique, aim to extend their aqueous solubility and biological properties. UV-Vis absorption, fluorescence, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), proton nuclear magnetic resonance (¹H NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD) and computational simulations confirmed the formation of EOC/MβCD-ICs. Result of solubility studies proved the enhanced solubilization of EOC in the presence of MβCD in aqueous and double reciprocal profiles substantiated the guest/host stoichiometry of 1:1. TGA and DSC studies indicated the improved stability of EOC in MβCD-ICs. The efficiency of ICs in terms of the antioxidant activity was verified and the IC displayed higher antioxidant activity compared to that of free EOC, as determined by free radical scavenging assay. Finally, the antibacterial effect of EOC/MβCD-ICs against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria was demonstrated. Overall results not only revealed the potential of MβCD on the bioavailability, solubility and stability, but also that the intensification caused by the IC may be greater that the antioxidant and antibacterial effects of the selected EOC for this study.