Natural Antibiotics Research Articles

Production, Purification, Characterization and Anti biofilm activity of natural antibiotic by Actinokineospora cibodasensis from marine water

Health sector faces a distress globally because of the scarcity of newer antibiotics against drug resistant pathogens. Innovations in developing new antibiotics is the solution to combat the drug resistant pathogens. This alarming situation requires advanced, potential and effective antibiotics. Secondary metabolite products from microbes remain as the main origin for many of the antibiotics in the market today and are also found to be promising till date. Out of the microbes, the major share of antibiotic production is reported by Actinomycetes, which are Gram positive, anaerobic, filamentous bacteria. They are currently being exploited through new approaches to improve the efficiency of commercially valuable antibiotics. Since natural environment stands a potential source of innovative and novel antimicrobials, this investigation was performed to test the potential of selected marine actinomycetes. Of the screened ones, Actinokineospora is potential enough to cease the growth of biofilm formation. This strain was identified by molecular characterization as Actinokineospora cibodasensis. It was selected to extract secondary metabolites by submerged fermentation and made to undergo further purification and structural analyses for the search of bioactive components. Presence of streptomycin like compound by Gas Chromatography Mass Spectrometry led to a breakthrough in the study which had been confined by High Performance Thin Layer Chromatography and Fourier Transform Infra-Red Spectroscopy techniques by comparing with standards. Gene expression studies showed that the selected strain can down regulate the genes in the formation of biofilm by the test organism Pseudomonas aeruginosa. The bioactive compound from Actinokineospora is an ecofriendly product along with a biofilm mitigating activity on medical devices. Rare actinomycetal isolate was able to produce the antibiotic which could apply on medical device to reduce the infections during the treatment. This antibiotic coating on life saving devices will provide the ultimate protection for patients.

Phenolic Substitution in Fidaxomicin: A Semisynthetic Approach to Antibiotic Activity Across Species.

Fidaxomicin (Fdx) is a natural product antibiotic with potent activity against Clostridioides difficile and other Gram-positive bacteria such as Mycobacterium tuberculosis. Only a few Fdx derivatives have been synthesized and examined for their biological activity in the 50 years since its discovery. Fdx has a well-studied mechanism of action, namely inhibition of the bacterial RNA polymerase. Yet, the targeted organisms harbor different target protein sequences, which poses a challenge for the rational development of new semisynthetic Fdx derivatives. We introduced substituents on the two phenolic hydroxy groups of Fdx and evaluated the resulting trends in antibiotic activity against M. tuberculosis, C. difficile, and the Gram-negative model organism Caulobacter crescentus. As suggested by the target protein structures, we identified the preferable derivatisation site for each organism. The derivative ortho-methyl Fdx also exhibited activity against the Gram-negative C. crescentus wild type, a first for fidaxomicin antibiotics. These insights will guide the synthesis of next-generation fidaxomicin antibiotics.

Triepoxide formation by a flavin-dependent monooxygenase in monensin biosynthesis

Monensin A is a prototypical natural polyether polyketide antibiotic. It acts by binding a metal cation and facilitating its transport across the cell membrane. Biosynthesis of monensin A involves construction of a polyene polyketide backbone, subsequent epoxidation of the alkenes, and, lastly, formation of cyclic ethers via epoxide-opening cyclization. MonCI, a flavin-dependent monooxygenase, is thought to transform all three alkenes in the intermediate polyketide premonensin A into epoxides. Our crystallographic study has revealed that MonCI’s exquisite stereocontrol is due to the preorganization of the active site residues which allows only one specific face of the alkene to approach the reactive C(4a)-hydroperoxyflavin moiety. Furthermore, MonCI has an unusually large substrate-binding cavity that can accommodate premonensin A in an extended or folded conformation which allows any of the three alkenes to be placed next to C(4a)-hydroperoxyflavin. MonCI, with its ability to perform multiple epoxidations on the same substrate in a stereospecific manner, demonstrates the extraordinary versatility of the flavin-dependent monooxygenase family of enzymes.

An expanded CRISPR-Cas9-assisted recombineering toolkit for engineering genetically intractable Pseudomonas aeruginosa isolates.

Much of our current understanding of microbiology is based on the application of genetic engineering procedures. Since their inception (more than 30 years ago), methods based largely on allelic exchange and two-step selection processes have become a cornerstone of contemporary bacterial genetics. While these tools are established for adapted laboratory strains, they have limited applicability in clinical or environmental isolates displaying a large and unknown genetic repertoire that are recalcitrant to genetic modifications. Hence, new tools allowing genetic engineering of intractable bacteria must be developed to gain a comprehensive understanding of them in the context of their biological niche. Herein, we present a method for precise, efficient and rapid engineering of the opportunistic pathogen Pseudomonas aeruginosa. This procedure relies on recombination of short single-stranded DNA facilitated by targeted double-strand DNA breaks mediated by a synthetic Cas9 coupled with the efficient Ssr recombinase. Possible applications include introducing single-nucleotide polymorphisms, short or long deletions, and short DNA insertions using synthetic single-stranded DNA templates, drastically reducing the need of PCR and cloning steps. Our toolkit is encoded on two plasmids, harboring an array of different antibiotic resistance cassettes; hence, this approach can be successfully applied to isolates displaying natural antibiotic resistances. Overall, this toolkit substantially reduces the time required to introduce a range of genetic manipulations to a minimum of five experimental days, and enables a variety of research and biotechnological applications in both laboratory strains and difficult-to-manipulate P. aeruginosa isolates.

Telacebec Interferes with Virulence Lipid Biosynthesis Protein Expression and Sensitizes to Other Antibiotics.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a public health issue, particularly due to multi-drug-resistant Mtb. The bacillus is wrapped in a waxy envelope containing lipids acting as essential virulence factors, accounting for the natural antibiotic resistance of mycobacteria. Telacebec (previously known as Q203) is a promising new anti-TB agent inhibiting the cytochrome bc1 complex of a mycobacterial electron transport chain (ETC). Here, we show that the telacebec-challenged M. bovis BCG exhibited a reduced expression of proteins involved in the synthesis of phthiocerol dimycocerosates (PDIMs)/phenolic glycolipids (PGLs), lipid virulence factors associated with cell envelope impermeability. Consistently, telacebec, at concentrations lower than its MIC, downregulated the transcription of a PDIM/PGL-synthesizing operon, suggesting a metabolic vulnerability triggered by the drug. The drug was able to synergize on BCG with rifampicin or vancomycin, the latter being a drug exerting a marginal effect on PDIM-bearing bacilli. Telacebec at a concentration higher than its MIC had no detectable effect on cell wall PDIMs, as shown by TLC analysis, a finding potentially explained by the retaining of previously synthesized PDIMs due to the inhibition of growth. The study extends the potential of telacebec, demonstrating an effect on mycobacterial virulence lipids, allowing for the development of new anti-TB strategies.

Introducing a novel and natural antibiotic for the treatment of oral pathogens: Abelmoschus esculentus green-formulated silver nanoparticles

Abstract Nanotechnology can solve many biomedical problems and cause transformation in the field of health and pharmaceuticals. The use of this technology in removing pathogenic bacteria is of great interest. The introduction of a strong antibacterial agent is very important to control pathogenic bacteria, especially strains resistant to antibiotics. The aim of this research was to synthesize silver nanoparticles (AgNPs) with the help of Abelmoschus esculentus aqueous extract and investigate its antibacterial properties against oral pathogens. Our study examined the ability of AgNPs to inhibit the dental bacterial growth and anti-adherence in vitro. The biosynthesized AgNPs@Abelmoschus esculentus were characterized by FT-IR, UV–Vis, and SEM tests. The physical and chemical investigation of the synthesized AgNPs showed that the particles were produced in nano dimensions, spherical shape, and without any impurities. In antibacterial test, the 8 µg/mL exhibited the lowest minimum inhibitory concentrations (MICs) against Porphyromonas gingivalis and Streptococcus mutans (MIC = 8 µg/mL). In vitro adherence of S. mutans was significantly prevented by AgNPs@Abelmoschus esculentus (MIC = 8–16 µg/mL). According to the results, the AgNPs@Abelmoschus esculentus may be good candidates for the oral hygiene agents to prevent periodontopathic conditions and dental caries.

Thiostrepton alleviates experimental colitis by promoting RORγt ubiquitination and modulating dysbiosis.

Thiostrepton (TST) is a natural antibiotic with pleiotropic properties. This study aimed to elucidate the therapeutic effect of TST on experimental colitis and identify its targets. The effect of TST on colon inflammation was evaluated in a dextran sulfate sodium (DSS)-induced colitis model and a T-cell transfer colitis model. The therapeutic targets of TST were investigated by cytokine profiling, immunophenotyping and biochemical approaches. The effect of TST on the gut microbiota and its contribution to colitis were evaluated in mice with DSS-induced colitis that were subjected to gut microbiota depletion and fecal microbiota transplantation (FMT). Alterations in the gut microbiota caused by TST were determined by 16S rDNA and metagenomic sequencing. Here, we showed that TST treatment significantly ameliorated colitis in the DSS-induced and T-cell transfer models. Specifically, TST targeted the retinoic acid-related orphan nuclear receptor RORγt to reduce the production of IL-17A by γδ T cells, type 3 innate lymphoid cells (ILC3s) and Th17 cells in mice with DSS-induced colitis. Similarly, TST selectively prevented the development of Th17 cells in the T-cell transfer colitis model and the differentiation of naïve CD4+ T cells into Th17 cells in vitro. Mechanistically, TST induced the ubiquitination and degradation of RORγt by promoting the binding of Itch to RORγt. Moreover, TST also reversed dysbiosis to control colonic inflammation. Taken together, these results from our study describe the previously unexplored role of TST in alleviating colonic inflammation by reducing IL-17A production and modulating dysbiosis, suggesting that TST is a promising candidate drug for the treatment of IBD.

Evaluation of the Antifungal Effect of Rhus verniciflua Stokes Extract for Oral Application Potential.

Background and Objectives: This study confirms the possibility of using Rhus verniciflua Stokes (RVS) extract as a natural treatment for oral candidiasis. Materials and Methods: RVS was extracted with 70% ethanol to examine the antioxidant activity through polyphenol, flavonoid content, and DPPH (1,1-diphenyl-2-picrylhydrazyl). To evaluate the antifungal effect against Candida albicans (C. albicans; KCTC 7965/ATCC 10231) and evaluate the stability of RVS, a water-soluble tetrazolium salt (WST-1) assay was performed in human keratinocytes (HaCaT). Results: The findings revealed that RVS extract has fairly high antioxidant activity. The clear zones of the RVS extract against C. albicans increased in diameter due to the inhibition of fungal growth at higher concentrations. Treatment with the 1.25 mg/mL RVS extract had a more than 99% antifungal effect against C. albicans, and the 20 mg/mL RVS extract had a 100% antifungal effect. The WST-1 assay showed that the RVS extract induced low cell viability in the HaCaT cells, which inhibited their proliferation, and the RVS extract is also toxic to normal cells. Conclusions: Although the RVS extract with high antioxidant activity showed clear antifungal activity against C. albicans, it exhibited a low survival rate. Therefore, the development of a safe natural antibiotic is necessary.

Antibiotic hyper-resistance in a class I aminoacyl-tRNA synthetase with altered active site signature motif

Antibiotics target key biological processes that include protein synthesis. Bacteria respond by developing resistance, which increases rapidly due to antibiotics overuse. Mupirocin, a clinically used natural antibiotic, inhibits isoleucyl-tRNA synthetase (IleRS), an enzyme that links isoleucine to its tRNAIle for protein synthesis. Two IleRSs, mupirocin-sensitive IleRS1 and resistant IleRS2, coexist in bacteria. The latter may also be found in resistant Staphylococcus aureus clinical isolates. Here, we describe the structural basis of mupirocin resistance and unravel a mechanism of hyper-resistance evolved by some IleRS2 proteins. We surprisingly find that an up to 103-fold increase in resistance originates from alteration of the HIGH motif, a signature motif of the class I aminoacyl-tRNA synthetases to which IleRSs belong. The structural analysis demonstrates how an altered HIGH motif could be adopted in IleRS2 but not IleRS1, providing insight into an elegant mechanism for coevolution of the key catalytic motif and associated antibiotic resistance.

Seed germination and vegetative propagation of Helichrysum odoratissimum

Helichrysum odoratissimum is a popular indigenous herb of South Africa, well known for its aromaticity. It offers potential as a source of extracts for the development of cosmeceutical products as it has been reported to be a natural antibiotic, and has antifungal, antimicrobial, antioxidant and antiviral properties. In order to be commercialized, a sustainable production system is required to ensure a consistent supply of good quality material. Therefore, the production of H. odoratissimum by seed and stem cutting was evaluated. The interactive effect of different seed priming methods and temperature levels were investigated on germination indices of H. odoratissimum seeds. A randomized complete block design with three replicates was used to evaluate the effect of season, cutting position, rooting hormone and growth media on survival percentage, number of buds, number of leaves, rooting percentage, number of roots per cutting and root length of H. odoratissimum stem cuttings. Data for both aspects was analysed using ANOVA and means with significant differences were separated with a t-test at 5% level of significance. Smoke treated seeds incubated at 20 °C had a significantly higher germination percentage (91,7%), mean germination rate (0.59) and coefficient velocity of germination (59.5) compared to most other treatments. Almost all factors tested in vegetative propagation significantly affected parameters measured. Apical cuttings taken during autumn resulted in significantly higher survival (78.5) and rooting percentages (71.1%) compared to other seasons. Cuttings planted in a perlite, vermiculite and sand mixture during autumn significantly outperformed all other season/media combinations with regards to rooting percentage (75%). PGR application improved the number of roots obtained significantly in autumn and winter, but not in summer and spring, compared to the control. It was therefore concluded that, for higher seed germination H. odoratissimum seeds must be primed with smoke water and incubated at 15–20 °C and cuttings may be taken autumn for higher rooting and survival rates as well as improved root length. A PGR application can be beneficial depending on the type of medium used.

Utilising cottonseed in animal feeding: A dialectical perspective

AbstractAs the population expands livestock industry faces challenges including protein inadequacy and infectious diseases. Natural alternatives can help mitigate these issues, for example, by incorporating plant‐derived metabolites containing appropriate concentrations of natural antibiotics and health‐promoting agents into feed supplements. One promising source is cottonseed, a fat‐ and protein‐rich by‐product of cotton plant (Gossypium spp.). During processing, gossypol, a natural substance with potential adverse effects when consumed long‐term, is often eliminated. However, gossypol has broad‐spectrum antiviral and antimicrobial properties, making it a potential solution to feed safety and animal health concerns. Here, we outline the challenges faced in animal husbandry and discuss how cottonseed may address diverse scenarios.

Identification of antibiotic resistant bacteria communities and a GeoChip based study of resistome in Fusarium wilt diseased and healthy soil

Soil plays a crucial role as a significant reservoir for antibiotic resistance genes (ARGs). Despite the extensive research conducted in this area, there remains a need for further investigation, particularly concerning diverse types of agricultural soil. This comprehensive study examined Fusarium wilt diseased and healthy soil samples to investigate the spectrum of ARGs and identify bacteria potentially harboring these genes. The level of antibiotic resistance (AR) in the two soil types was detected by using culture plate counts (PC). We quantified and identified antibiotic resistant bacteria (ARB) against nine antibiotics. From the PC results, the relative number of ARB (number of ARB/total number culturable bacteria) resistant to erythromycin, lincomycin, sulfonamides, streptomycin sulfate, kanamycin, and enrofloxacin in the diseased soil was significantly higher than that in the healthy soil (One-way ANOVA, p < 0.01). The GeoChip (version 5.0) was employed to identify ARGs and antibiotic biosynthetic genes (ABGs). Interestingly, despite the presence of similar ARGs in both soil types, the Fusarium wilt diseased soil demonstrated a significantly elevated abundance of the tetracycline (tetX) resistance gene compared to the healthy soil. A robust correlation (r ≥ 0.8) between multidrug efflux pumps and ARGs indicates that natural antibiotics as selective pressures for transportation mechanisms. Our analysis identified diverse ARB phylotypes and multiple ARGs in both soil types. Incorporating these soil types into ARGs risk assessments and relevant monitoring is essential for a comprehensive understanding of AR dynamics in various environments.

Pseudomonas aeruginosa biofilm formation and its resistance to beta-lactam antibiotics

ABSTRACT Introduction: An opportunistic pathogen, Pseudomonas aeruginosa is a Gram-negative bacteria that causes acute and chronic human infections. By adhering to appropriate surfaces and creating a biofilm matrix, Pseudomonas aeruginosa has a high-resistance structure. Due to biofilm resistance mechanisms, this bacterial biofilm may increase natural antibiotic resistance. Antibiotics have difficulty penetrating the exopolysaccharide matrix that makes up the biofilm structure (Psl, Pe, alginate, and eDNA). Alginate is involved in generating mucus, and Psl and Pel components are implicated in biofilm development and antibiotic resistance. Due to the connection between biofilm production and antibiotic resistance, Pseudomonas aeruginosa involves mechanisms of beta-lactam antibiotic resistance. Objective: On this basis, learning more about the connection between Pseudomonas aeruginosa bacteria's ability to form biofilms and their resistance to beta-lactam antibiotics is essential. Methods: We use literature methods from various literature on the biofilm formation of P. aeruginosa and its resistance to beta-lactam antibiotics, including research papers and studies with no restrictions types of studies included in this article. Discussion: Pseudomonas aeruginosa has intrinsic and adaptive antibiotic resistance mechanisms. Decreased membrane permeability, the production of enzymes resistant to antibiotics, chromosomal changes, and horizontal gene transfer from other bacteria contribute to antimicrobial resistance. Beta-lactam antibiotic resistance mechanisms are known to be developed by Pseudomonas aeruginosa. The resistance characteristics of Pseudomonas aeruginosa may change phenotypically due to biofilm development. This article will be helpful in future research on Pseudomonas aeruginosa therapy and medication.

Evaluation of the antibacterial activity of nano berberine adsorbed bacterial cellulose material

Berberine can be considered a natural antibiotic plant with strong antibacterial and antifungal activities. The pr oblem of bioavailability and poor solubility can be overcome by formulating berberine at nanoparticles, which opens up a vast range of applications. In this study, berberine nanoparticles (BerNPs) were adsorbed on bacterial cellulose forming a composite with the potential for antibacterial material. The pr operties of BerNPs and before and after BerNPs adsorption were analysed by FE-SEM, XRD, and FT-IR methods. The antibacterial activity of BerNPs and its composite was examined invitro by the co-culture method with Escherichiacoli and Streptococcus pyogenes. The results indicated that BerNPs exhibited gr eat antibacterial pr operties against E. coliand S. pyogenes. The optimum capacity of loading BerNPs (50-60 nm) above the biological cellulose was after 2 hours of soaking. The against E. coli and S. pyogenes was over 80%.

Antibacterial potential of biosynthesized silver nanoparticles using Nepeta sessilifolia Bunge and Salvia hydrangea DC. ex Benth. extracts from the natural habitats of Iran's Rangelands

BackgroundNowadays, the use of herbal extracts for the production of nanoparticles has attracted a lot of attention due to the fast reaction, economy, and compatibility with the environment. The aim of the present study is the biosynthesis of silver nanoparticles from the extracts of Nepeta sessilifolia Bunge and Salvia hydrangea DC. ex Benth. and their antibacterial activity was measured.MethodsFor this purpose, the flowering branch of N. sessilifolia and the flower of S. hydrangea were randomly collected from three places, respectively, from the rangelands of Aqdash Mountain and Biabe in Isfahan province, Iran in May 2021. After extracting aqueous extracts by hot method, silver nanoparticles were synthesized by the biological method. Green synthesized silver nanoparticles were analyzed by UV–Vis spectroscopy, XRD, FTIR, and FESEM-EDAX. The antibacterial effect was evaluated by diffusion method in agar and determination of minimum growth inhibitory and lethal concentration (MIC and MBC) by dilution method in liquid culture medium.ResultsBased on the results of UV–Vis spectroscopy, silver nanoparticles synthesized from N. sessilifolia and S. hydrangea had distinct absorption peaks at wavelengths of 407 to 424 nm and 414 to 415 nm, respectively. The crystalline nature of these synthetic silver nanoparticles was confirmed by XRD. FESEM analysis showed that the size of biosynthesized silver nanoparticles from N. sessilifolia and S. hydrangea extracts were 10–50 nm and 10–80 nm, respectively, and were cubic. The results of diffusion in agar showed that the largest diameter of the growth inhibition zone belonging to the synthetic silver nanoparticles from both extracts of N. sessilifolia (~ 26.00 mm) and S. hydrangea (~ 23.50 mm) was against Gram-positive bacteria Staphylococcus aureus. The most vigorous killing activity by synthetic silver nanoparticles from N. sessilifolia extract was against Klebsiella pneumoniae with a value of 250 μg/mL, two times stronger than rifampin.ConclusionTherefore, the studied extracts can be suitable options for fast and safe green synthesis of silver nanoparticles effective against some bacterial strains. These synthetic silver nanoparticles can be used as possible options and have strong potential for the production of natural antibiotics.

Use of Spirulina platensis and Curcuma longa as Nutraceuticals in Poultry

Since the banning of antibiotics in animal feeds (2006), there has been an increase in the number of studies looking for alternatives to stimulate the gut immune system. The main objective of our review article is to underline the nutraceutical properties of Curcuma longa and Spirulina platensis in the broiler chicken industry, and the experimental data were obtained by analyzing literature sources. Spirulina platensis is widely recognized as a valuable protein source, containing approximately 55–70% protein, 25% carbohydrates, essential amino acids, and 18% fatty acids. It is also rich in various vitamins like thiamin, riboflavin, pyridoxine, vitamin B12, vitamin C, gamma-linolenic acid, phycocyanins, tocopherols, chlorophyll, beta-carotenes, carotenoids, exhibiting positive effects on growth performance, gut integrity, and immunity. The anti-inflammatory effect of spirulina supplementation at different levels showed a decrease in caspase-3 and the TNF-α immunolabeling index; a reduction in IL-1β, IL-2 and IFN-γ; and an increase in the expression of the anti-inflammatory cytokine IL-4. Spirulina inhibits the synthesis of cytokines IL-1, IL-6, and TNF-gamma in addition to the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) enzymes. Turmeric also positively influences the growth, egg production, and overall health of chickens. Curcumin, the most potent component of turmeric, possesses additional pharmacological activities, including hepatoprotective, immunostimulant, and anticancer effects. Its immunomodulatory properties greatly enhance the immune system response, acting as a natural antibiotic against pathogens and decreasing levels of proinflammatory interleukins IL-1β, IL-6, IL-2, IL-18, and TNF-α.

Returning to Nature for the Next Generation of Antimicrobial Therapeutics.

Antibiotics found in and inspired by nature are life-saving cures for bacterial infections and have enabled modern medicine. However, the rise in resistance necessitates the discovery and development of novel antibiotics and alternative treatment strategies to prevent the return to a pre-antibiotic era. Once again, nature can serve as a source for new therapies in the form of natural product antibiotics and microbiota-based therapies. Screening of soil bacteria, particularly actinomycetes, identified most of the antibiotics used in the clinic today, but the rediscovery of existing molecules prompted a shift away from natural product discovery. Next-generation sequencing technologies and bioinformatics advances have revealed the untapped metabolic potential harbored within the genomes of environmental microbes. In this review, we first highlight current strategies for mining this untapped chemical space, including approaches to activate silent biosynthetic gene clusters and in situ culturing methods. Next, we describe how using live microbes in microbiota-based therapies can simultaneously leverage many of the diverse antimicrobial mechanisms found in nature to treat disease and the impressive efficacy of fecal microbiome transplantation and bacterial consortia on infection. Nature-provided antibiotics are some of the most important drugs in human history, and new technologies and approaches show that nature will continue to offer valuable inspiration for the next generation of antibacterial therapeutics.

Therapeutic potential of natural products and antibiotics against bovine mastitis pathogen of cows and buffaloes.

The present study aims toevaluate the prevalence and antimicrobial sensitivity ofStaphylococcus aureus associated with bovine mastitis toselected antibiotics and plant extracts. Inthe current study, 140milk samples were collected from cows and buffaloes. Among the 140samples, 93samples were positive for sub-clinical mastitis based onthe California Mastitis Test (CMT). Out ofthe total positive samples, 45 were confirmed for S.aureus onaMannitol salt agar media. The antimicrobial susceptibility test revealed that 44.82% ofthe isolates were resistant tocefoxitin (oxacillin) confirming methicillin-resistant S.aureus (MRSA) with ahigher percentage (51.61%) inthe buffalo than inthe cow samples. Furthermore, the PCR assay confirmed the presence ofthemecA gene inall the MRSA isolates. Among the seven tested antibiotics, sulfamethoxazole + trimethoprim showed high efficacy (71.1%) against methicillin-susceptible S.aureus isolates (MSSA). Oxytetracycline and sulfamethoxazole+ trimethoprim showed 20% efficacy against MRSA followed byenrofloxacin (10%). Onthe other hand, the tested samples from Pistacia chinensis revealed that the ethyl acetate extract ofbark showed amaximum zone ofinhibition of21.3mm against MSSA and MRSA isolates at3000μg/disc. Moreover, the methanol extract ofCotoneaster microphyllus formed a12.3mm and 9.1mm zone ofinhibition against the MSSA and MRSA isolates, respectively.

Synthesis, Reaction Mechanism, DNA Cleavage and Antitumor Properties of Naphthoquinone‐Based Enediynes

AbstractUnder physiological conditions, natural enediynes antibiotics generate free radicals through a cycloaromatization reaction. The resulting highly reactive radicals can abstract hydrogen atoms on the phosphate backbone of DNA, leading to high cytotoxicity. On the other hand, anthraquinone‐fused compounds such as daunomycin and adriamycin can insert into DNA through planar aromatic ring structures, resulting in strong DNA damage. To this end, a series of naphthoquinone‐based enediynes were designed and synthesized by adjusting the type of terminal alkyne to modulate their water solubility and radical generation property. Theoretical calculations suggest that the naphthoquinone‐based enediyne generates radicals through a rearrangement (1,3‐proton transfer) followed by Myers‐Saito cyclization processes, with a much lower activation free energy barrier than Bergman cyclization (24.2 kcal/mol vs 39.8 kcal/mol). Differential scanning calorimetry and electron paramagnetic resonance results showed that naphthoquinone‐based enediynes undergo cycloaromatization at relatively low temperatures, resulting in the generation of highly reactive radical species. The enediynes with optimal water solubility displayed strong DNA cleavage ability at micromolar level and high cytotoxicity towards Hela cells, providing a half‐inhibitory concentration of 8.19 μM.

Cinnamon as a Potential Feed Additive: Beneficial Effects on Poultry Health and Production Performances – An Update

According to the Food and Agricultural Organization, global poultry output increased from approximately 115 million tons in 2016 to around 136 million tons in 2023. Poultry production has increased significantly with the dramatic uptick in meat and egg demand. Feed accounts for between 65 and 70 percent of total production costs, making it the largest chicken industry expense. This is why it's important to maximize the transformation of poultry feed into feed with a high biological value while taking as many steps as possible to protect feed quality and reduce feed costs. The use of feed additives in poultry feed has recently gained popularity and has been essential to increase feed efficiency and growth rate, which typically leads to reduced costs. The meat's texture, consistency, and nutritional content are all improved, and its shelf life is lengthened as a bonus. Feed additives are a fantastic tool for boosting a poultry farm's bottom line. For example, cinnamon (Cinnamomum verum) is often used as a traditional feed supplement. Rather than antibiotics, the poultry industry could benefit from using cinnamon as a natural antibiotic replacement, which would benefit animal welfare, consumer health, and the bottom line. The performance index, feed intake, FCE performance, and weight growth of poultry can all be improved by including cinnamon in the feed at varied concentrations. The digestive health and intestinal microbial population of hens are enhanced by a diet containing bioactive components of cinnamon. Cinnamon essential oils' popularity stems from their many valuable features, such as their ability to increase gastric enzyme synthesis and other biofunctional benefits. This review focuses on the possible advantages of cinnamon as a natural feed supplement for chickens, particularly about their intestinal microbiota, blood chemistry, nutrient absorption, gene expression, and immunology.