Antimicrobial Bioactivity Research Articles

Three New Ent-Kaurane Diterpenes with Antibacterial Activity from Sigesbeckia orientalis.

Three novel ent-kaurane diterpenes, namely sigesbeckin A-C (1-3), in conjunction with eight previously identified analogues (4-11), were isolated from Sigesbeckia orientalis. Their chemical structures were resolved through multiple spectroscopic analyses. All compounds were assessed for antimicrobial bioactivity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains. In particular, compounds 1 and 5 demonstrated moderate efficacy, with MIC values of 64 μg/mL. Moreover, compounds 3, 5, and 11 were found to synergize with doxorubicin hydrochloride (DOX) and vancomycin (VAN) against MRSA and VRE. The aforementioned findings offer valuable insights for the development of novel alternatives to antibiotics, which can effectively tackle the escalating issue of antibiotic resistance.

Microbial Fermentation and Therapeutic Potential of p-Cymene: Insights into Biosynthesis and Antimicrobial Bioactivity

p-Cymene (p-C) [1-methyl-4-(1-methylethyl)-benzene] is a monoterpene found in a variety of plants and has several biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. This paper explores the microbial fermentation pathways involved in the biosynthesis of p-C, with an emphasis on its potential as a therapeutic agent. Through microbial and biochemical processes, p-C can be produced using renewable precursors such as limonene and 1,8-cineole. Recent advances in fermentation technology have enhanced the efficiency of p-C production, highlighting its role in various industries. Additionally, this paper reviews the antimicrobial bioactivity of p-C, focusing on its ability to inhibit pathogens and modulate immune responses. The integration of microbial biosynthesis and fermentation methods offers a sustainable approach to producing p-C for applications in the perfume, cosmetics, food, and pharmaceutical sectors. Understanding these biosynthetic pathways is crucial for advancing the use of p-C as a bio-based chemical with therapeutic potential. In particular, p-C inhibits the expression of cytokine signal 3 in intestinal inflammation and modulates antioxidant and immunomodulatory systems to protect barrier cells and maintain the mucus layer.

Synthesis and Preliminary Biological study of New Chalcone Derivatives Containing Isoxazoline Moiety

In this research work, synthesis, antimicrobial and antioxidant bioactivity of a chain of compounds having unsaturated ketones bond and isoxazoline moiety have been described. New chalcone derivatives containing isoxazoline moiety have been synthesized. Generally, Chalcones are unsaturated ketones bearing (-CO-CH=CH-) as reactive ketoethylenic group that give the bright yellow colored compounds due to this chromophore group. Firstly, chalcones (IIa-d) have been prepared by cyclocondensation (Claisen-Schmidt condensation) of triphenyl aminobenzaldehyde with different substituted acetophenone in ethyl alcohol to produce a series of chalcones compounds with bright yellow colored as a starting material,. The next step involving the novel chalcones (IIa-d) reacted with hydroxylamine hydrochloride afforded a new isoxazoline compounds (IIIa-d) in basic medium. The prepared compounds were fully characterized by melting points, FTIR, 1H-NMR spectroscopy, 13 C-NMR for some compounds and CHNS techniques. The reactions have been monitored by TLC (Thin Layer Chromatography) technique. The synthesised compound IId showed significant bioactivity against the gram-negative bacteria species. Also, the antioxidant activity of the some new synthesized compounds was evaluated and determined against the DPPH radical (1.1-diphenyl-2-picrylhydrazyl) and compared to that of a standard natural antioxidant, Ascorbic acid, compound IIb showed higher antioxidant activity by using the free radical DPPH. The outcomes of investigation enhanced the activity of new derivatives as antimicrobial reagent.

Copper substituted hydroxyapatite reinforced gelatin/polyvinyl alcohol/silk fibre-based scaffold for bone tissue engineering application

In order to restore the function of the damaged tissues, it is essential to find suitable ways which are capable of customizing tissue engineering constructs for each patient. The present study presents the hydrothermal synthesis of copper hydroxyapatite (Cu-HAP), as well as the electrospinning fabrication of gelatin/PVA/silk fibre-Cu-HAP scaffolds. The fabricated scaffold was characterized using XRD, FT-IR, SEM-EDAX in order to confirm the phase formation, functional group, surface topography and elemental composition respectively. The gelatin-PVA-silk fibre with 60 wt % Cu-HAP showed highest porosity (99 %) and highest mechanical strength (96. 13 MPa). To fulfil the requirements of bone tissue engineering the biological application such as antimicrobial activity, hemocompatibility, bioactivity and cell-line studies were carried out. Gelatin/PVA/silk fibre with 60 wt % Cu-HAP scaffold showed excellent zone of inhibition (E. coli - 75 ± 1.38 mm, S. aureus - 65 ± 1.40 mm, C. albicans - 68 ± 1.26 mm), good hemocompatibility (1.20 ± 0.06) with human blood and surface was uniformly covered with HAP in bioactivity studies. That the fabricated gelatin-PVA-silk fibre/Cu-HAP could be effective and suitable as a bone graft material.

Synthesis of imidazole-fused nitrogen-bridgehead heterocycles catalysed by lipase and their antifungal and antimicrobial bioactivity

An effective approach for selective C–N bond formation for synthesising imidazo[1,2-a] pyridine-based heterocycles using porcine pancreatic lipase (PPL) as a biocatalyst has been devised.

Production and Characterization of Bioactive and Antimicrobial Titanium Oxide Surfaces with Silver Nanoparticles and a Poly(lactic Acid) Microfiber Coating

Silver nanoparticles (AgNp) were deposited on highly porous TiO2 surfaces by the dripping of a colloidal AgNp solution to provide antimicrobial activity. Micro-porous TiO2 surfaces were obtained on commercially pure titanium by micro-arc oxidation in an electrolyte containing Ca and P precursors. In addition, as silver can be toxic to cells, these surfaces were uniformly covered with the biocompatible and bioresorbable poly(lactic acid) (PLA) polymer by electrospinning, aiming at promoting a controlled release of silver ions to the medium. The resulting AgNp-containing surfaces were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), and in vitro assays were performed to evaluate their antimicrobial activity and bioactivity. Tests revealed that the surfaces showed antimicrobial activity against Staphylococcus aureus, with better results for the surfaces without PLA. However, all the surfaces presented good biocompatibility in assays with mouse MC3T3-E1 pre-osteoblasts, and greater cell differentiation for the polymer-coated surfaces. Finally, the PLA ultrafine fibers electrospun on the TiO2/AgNp surfaces allowed a controlled release of silver ions in the phosphate-buffered saline (PBS) medium.

Silver-doped hydroxyapatite laden chitosan–gelatin nanocomposite scaffolds for bone tissue engineering: an in-vitro and in-ovo evaluation

Despite the advancements in bone tissue engineering, the majority of implant failures are caused due to microbial contamination. So, efforts are being made to develop biomaterial with antimicrobial property enhancing the regeneration of damaged bone tissue. In the present study, chitosan–gelatin (CG) scaffolds containing silver-doped hydroxyapatite (AgHAP) nanoparticles at 0.5%, 1.0% and 1.5% (w/v) were fabricated by lyophilization technique. The results confirmed the synthesis of AgHAP nanoparticles and showed interconnected porous structure of the nanocomposite scaffolds with 89%–75% porosity. Similarly, the swelling percentage, degradation behavior and compressive modulus of CG-AgHAP nanocomposite scaffolds were 1666%, 40% and 0.7 MPa, respectively. The developed nanocomposite scaffolds revealed better antimicrobial properties and bioactivity. The cell culture studies showed favorable viability of Wharton’s jelly stem cells on CG-AgHAP nanocomposite scaffolds. CAM (chorioallantoic membrane) assay determined the angiogenic potential with better visualization of blood vessels in the CAM area. Hence, the obtained results confirmed that CG-AgHAP3 nanocomposite scaffold was the most suitable for bone tissue engineering applications among all scaffolds.

Enhanced antimicrobial properties and bioactivity of 3D-printed titanium scaffolds by multilayer bioceramic coating for large bone defects

The restoration of large bone defects caused by trauma, tumor resection, or infection is a major clinical problem in orthopedics and dentistry because postoperative infections, corrosion, and limited osteointegration of metal implants can lead to loosening of the implant. The aim of this study was to improve the surface properties of a 3D-printed (electron beam melting) Ti6Al4V-based macroporous scaffold by multilayer coating with bioactive silicate glasses (BAGs) and hydroxyapatite doped with a silver (AgHAP) or AgHAP additionally sonochemically modified with ZnO (ZnO-AgHAP). The coated scaffolds AgHAP_BAGs_Ti and ZnO-AgHAP_BAGs_Ti enhanced cytocompatibility in L929 and MRC5 cell lines and expressed bioactivity in simulated body fluid. A lower release of vanadium ions in coated samples compared to bare Ti scaffold indicates decreased dissolution of Ti alloy in coated samples. The coated samples reduced growth of Escherichia coli and Staphylococcus aureus for 4–6 orders of magnitude. Therefore, the 3D-printed Ti-based scaffolds coated with BAGs and (ZnO-)AgHAP have great potential for application as a multifunctional implant with antibacterial properties for the restoration of defects in load-bearing bones.

Antibacterial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG) development for its potential use in bioactive wound dressings

An adequate wound dressing reduces time of healing, provides cost-effective care, thereby improving patients’ quality life. An antimicrobial bioactivity is always desired, for that reason, the objective of this work is to design an antimicrobial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG). ChAgG nanostructured composite material is composed of chitosan from corn (Ch), and silver nanocrystals from garlic (Allium sativum). The nanocomposite obtained is the result of a series of experiments combining the graphene oxide (GrOx) with two members of the Amaryllidaceae family; garlic and onion (Allium cebae), which contain different sulfur materials. The characterization arrays confirmed the successful production of silver crystal, graphene oxidation and the blending of both components. The role of the chitosan as a binder between graphene and silver nanocrystals is proved. Moreover, the study discusses garlic as an optimal source that permits the synthesis of silver nanocrystals (AgNCs) (⁓ 2 to 10 nm) with better thermal and crystallinity properties. It was also confirmed the successful production of the ChAgG nanocomposite. Escherichia coli and Staphylococcus aureus were used to demonstrate the antibacterial bioactivity and L-929 fibroblast cells were utilized to visualize their biocompatibility. The proposed ChAgG nanomaterial will be useful for functionalizing specific fiber network that represents current challenging research in the fabrication of bioactive wound dressings.

A novel bioactive glass/graphene oxide composite coating for a polyether ether ketone-based dental implant.

Polyether ether ketone (PEEK) is a biocompatible material that lacks antimicrobial activity and bioactivity; therefore, is not appropriate for use as a dental implant. To overcome these deficiencies, a novel composite coating of bioactive glass and graphene oxide was prepared. PEEK discs were polished, cleaned, and the surface treated with sulfuric acid for 15min. The composite coating consisted of bioactive glass produced by the sol-gel route and doped with 0.75wt% graphene oxide. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy-energy dispersive spectroscopy analyses were employed to characterize the composite coating, and the coating adhesion strength quantified using a pull-off test. Cytotoxicity was assessed using osteoblast-like cells and gingival fibroblasts. The wettability of the coated and non-coated samples was determined by optical contact angle assessment, and bioactivity was assessed by immersion in simulated body fluid. The results revealed that the bioactive glass/graphene oxide composite coating, approximately 7 μm thick, was transparent, homogenous with few microcracks and microporosities, but adhered strongly and was not cytotoxic to either osteoblast-like cells or gingival fibroblasts. The wettability of the PEEK sample was increased to<20° after coating with the composite, and apatite formation was detectable after 14 days of immersion in simulated body fluid.

Insights into electrospun pullulan-carboxymethyl chitosan/PEO core-shell nanofibers loaded with nanogels for food antibacterial packaging

Nisin, a natural substance from Lactococcus lactis, displays a promising antibacterial ability against the gram-positive bacteria. However, it is susceptible to the external environment, i.e. temperature, pH, and food composition. In this study, a dual stabilization method, coaxial electrospinning, was applied to protect nisin in food packaging materials and the effect of nisin concentration on the properties of the nanofibers was investigated. The core-shell nanofibers with pullulan as a core layer and carboxymethyl chitosan (CMCS)/polyethylene oxide (PEO) as shell layer were prepared, and then the prepared CMCS-nisin nanogels (CNNGs) using a self-assembly method were loaded into the core layer of the nanofibers as antibacterial agents. The result revealed that the smooth surface can be observed on the nanofibers by microstructure characterization. The CNNGs-loaded nanofibers exhibited enhanced thermal stability and mechanical strength, as well as excellent antibacterial activity. Importantly, the as-formed nanofibers were applied to preserve bass fish and found that the shelf life of bass fish packed by CNNGSs with nisin at a concentration of 8 mg/mL was effectively extended from 9 days to 15 days. Taken together, the CNNGs can be well stabilized with the core-shell nanofibers, thus exerting significantly improved antimicrobial stability and bioactivity. This special structure exerts a great potential for application as food packaging materials to preserve aquatic products.

Biosynthetic novelty index reveals the metabolic potential of rare actinobacteria isolated from highly oligotrophic sediments.

Calculations predict that testing of 5 000-10 000 molecules and >1 billion US dollars (£0.8 billion, £1=$1.2) are required for one single drug to come to the market. A solution to this problem is to establish more efficient protocols that reduce the high rate of re-isolation and continuous rediscovery of natural products during early stages of the drug development process. The study of 'rare actinobacteria' has emerged as a possible approach for increasing the discovery rate of drug leads from natural sources. Here, we define a simple genomic metric, defined as biosynthetic novelty index (BiNI), that can be used to rapidly rank strains according to the novelty of the subset of encoding biosynthetic clusters. By comparing a subset of high-quality genomes from strains of different taxonomic and ecological backgrounds, we used the BiNI score to support the notion that rare actinobacteria encode more biosynthetic gene cluster (BGC) novelty. In addition, we present the isolation and genomic characterization, focused on specialized metabolites and phenotypic screening, of two isolates belonging to genera Lentzea and Actinokineospora from a highly oligotrophic environment. Our results show that both strains harbour a unique subset of BGCs compared to other members of the genera Lentzea and Actinokineospora. These BGCs are responsible for potent antimicrobial and cytotoxic bioactivity. The experimental data and analysis presented in this study contribute to the knowledge of genome mining analysis in rare actinobacteria and, most importantly, can serve to direct sampling efforts to accelerate early stages of the drug discovery pipeline.

Enhanced bioactivity and antimicrobial properties of α-tricalcium phosphate cement via PDA@Ag coating

The ideal orthopedic material demands excellent antimicrobial properties and bioactivity after initial implantation in vivo. In this paper, a polydopamine (PDA) film was prepared by dopamine self-polymerization on α-tricalcium phosphate (α-TCP) cement, and then silver (Ag) particles were immobilized in-situ on the surface of PDA via a dipping method. The presence of PDA and Ag in the composition of modified cement was confirmed by XPS. The results showed that after the modification of PDA coating and Ag particles, the roughness and contact angle of the cement increased from 36.4 nm to 120 nm and 18.8° to 58.8°, respectively. Moreover, the mineralization capacity of modified cement was considerably enhanced, generating dense hydroxyapatite (HA) layer with a thickness of 3.04 μm. Furthermore, the modified cement was revealed to provide antibacterial rate over 99 %. It is suggested that good bioactivity and antimicrobial properties of the cement can be achieved using the promising method.

Biotransformation-coupled mutasynthesis for the generation of novel pristinamycin derivatives by engineering the phenylglycine residue.

Streptogramins are the last line of defense antimicrobials with pristinamycin as a representative substance used as therapeutics against highly resistant pathogenic bacteria. However, the emergence of (multi)drug-resistant pathogens renders these valuable antibiotics useless; making it necessary to derivatize compounds for new compound characteristics, which is often difficult by chemical de novo synthesis due to the complex nature of the molecules. An alternative to substance derivatization is mutasynthesis. Herein, we report about a mutasynthesis approach, targeting the phenylglycine (Phg) residue for substance derivatization, a pivotal component of streptogramin antibiotics. Mutasynthesis with halogenated Phg(-like) derivatives altogether led to the production of two new derivatized natural compounds, as there are 6-chloropristinamycin I and 6-fluoropristinamycin I based on LC-MS/MS analysis. 6-Chloropristinamycin I and 6-fluoropristinamycin I were isolated by preparative HPLC, structurally confirmed using NMR spectroscopy and tested for antimicrobial bioactivity. In a whole-cell biotransformation approach using an engineered E. coli BL21(DE3) pET28-hmo/pACYC-bcd-gdh strain, Phg derivatives were generated fermentatively. Supplementation with the E. coli biotransformation fermentation broth containing 4-fluorophenylglycine to the pristinamycin mutasynthesis strain resulted in the production of 6-fluoropristinamycin I, demonstrating an advanced level of mutasynthesis.

Co-Expression of Pig IL-2 and Fusion Bovine Cathelicidin Gene by Recombinant Plasmids in Yeast and Their Promotion of Mouse Antibacterial Defense.

Simple Summary1. Oral inoculation with recombinant yeast co-expressing pig IL-2 and fused bovine cathelicidin (FBC) significantly enhanced systemic immunity in mice. 2. The inoculated mice displayed stronger resistance against E. coli or S. aureus infection. 3. Recombinant yeast co-expressing PIL-2 and FBC could facilitate the development of new immunopotentiator to prevent the infection of antibiotic-resistant bacteria.In order to develop an effective and safe immunomodulator to enhance the antimicrobial bioactivity and immunity of animals against infectious bacterial diseases, a recombinant plasmid pGAPZαA-IL2-B co-expressing pig interleukin-2 (PIL-2) and fused bovine cathelicidin (FBC) genes were constructed using the 2A self-cleavage technique. After being expressed in Pichia pastoris strain SMD1168, the recombinant yeast was administered orally to 5-week-old female ICR mice. The control mice were similarly dosed with P. pastoris with a blank plasmid or FBC recombinant plasmid alone. At 28 days post-treatment, the mice were challenged intraperitoneally with virulent strains of either E. coli or S. aureus. Compared with the control groups, the mice that received recombinant yeast co-expressing PIL-2/FBC manifested significant increases in the number of leukocytes, CD4+ and CD8+ T cells, IgG, and the gene expressions of TLRs(TLR1,4,6,9), antimicrobial peptides(CRP4 and CRAMP) and cytokines (IL-2, 4, 6, 7, 12, 15, 23, IFN-γ, and TNF-α) in the blood. Furthermore, the treated mice displayed significantly higher survival than the other two control groups after the challenge. These results suggest that the antimicrobial activity and immunity of animals can be effectively enhanced by the in vivo co-expression of IL-2 and the FBS gene, which can facilitate the development of new immunopotentiation molecules to overcome the infection of antibiotic-resistant bacteria.

Bioactivity and Therapeutic Potential of Kaempferol and Quercetin: New Insights for Plant and Human Health.

Plant secondary metabolites, especially flavonoids, are major metabolites widely found in plants that play several key roles in plant defence and signalling in response to stress conditions. The most studied among these flavonoids are kaempferol and quercetin due to their anti-oxidative potential and their key roles in the defence system, making them more critical for plant adaptation in stress environments. Kaempferol and quercetin in plants have great therapeutic potential for human health. Despite being well-studied, some of their functional aspects regarding plants and human health need further evaluation. This review summarizes the emerging potential of kaempferol and quercetin in terms of antimicrobial activity, bioavailability and bioactivity in the human body as well as in the regulation of plant defence in response to stresses and as a signalling molecule in terms of hormonal modulation under stress conditions. We also evaluated the safe use of both metabolites in the pharmaceutical industry.

Antimicrobial Bioactivity and GC-MS Analysis of Different Extracts of Corchorus olitorius L Leaves.

Results Crude extracts of Corchorus olitorius L leaves and their TLC-separated components demonstrated bioactivity against Staphylococcus aureus (14 mm), Streptococcus pneumoniae (16 mm), and Escherichia coli (11 mm) but neither against Candida albicans nor Mycobacteria tuberculosis. However, the overall zones of inhibition were smaller compared to the positive control (≥18 mm). GC-MS analysis of the active components revealed the presence of methyl esters. Conclusion Corchorus olitorius L is bioactive against both Gram-negative and Gram-positive bacteria but neither against fungi nor mycobacteria. The bioactivity is attributable to the presence of methyl esters. Since methyl esters already have proven bioactivity in some studies, they could be further studied and optimized for possible pharmaceutical use. Further, to provide a more comprehensive antimicrobial spectrum of Corchorus olitorius L in Uganda, purified active components could be investigated using a wider range of organisms.

Preliminary trials of the gold nanoparticles conjugated chrysin: An assessment of anti-oxidant, anti-microbial, and in vitro cytotoxic activities of a nanoformulated flavonoid

Abstract Chrysin (CHR), a dihydroxy flavone, exhibits several bioactivities, i.e., anti-oxidant, anti-inflammatory, and anti-cancer, and is known to possess limited aqueous solubility causing lowered bioavailability, and compromised therapeutic efficacy. Gold nanoparticles (AuNPs) conjugated chrysin (CHR–AuNPs) were prepared and characterized by UV-Vis, Fourier transform infra-red, X-ray diffraction, energy dispersive X-ray (EDX), and zeta potential analyses. The nanoformulated CHR–AuNPs were primarily examined on trial scale for their cytotoxic, anti-oxidant, and anti-microbial activity in comparison to the unformulated CHR. The CHR–AuNPs effectively scavenged the 2,2-diphenyl-1-picrylhydrazyl free radicals, also in comparison to CHR and AuNPs. The CHR–AuNPs also exhibited potential cytotoxic effects in a dose-dependent manner and demonstrated significant reduction (P = 0.05) of the cells proliferation, and growth of the human breast cancer cell lines, AMJ13, which were measured by 3-(4,5-dimethylthiazal-z-yl)-2,5-diphenyltetrazolium, and crystal violet assays, respectively. When compared with the pure CHR and free-AuNPs, the CHR–AuNPs exerted highest anti-microbial bioactivity against Staphylococcus aureus and Escherichia coli. The strong anti-oxidant, anti-microbial, as well as cytotoxic activity of the CHR–AuNPs preparation has the potential for clinical use after considerable appropriate developments.

Preclinical Pharmacokinetics, Biodistribution, and Acute Toxicity Evaluation of Caerin 1.9 Peptide in Sprague Dawley Rats.

Caerin 1.9 is a natural peptide derived from the skin secretions of the Australian tree frog (Litoria) with broad-spectrum antimicrobial and anticancer bioactivity. It improves the efficacy of a therapeutic vaccine and immune checkpoint inhibitor therapy when injected intratumorally and inhibits TC-1 tumor growth when applied topically through intact skin in a TC-1 murine tumor model. This paper investigated the pharmaceutical kinetic profile, the tissue distribution, and the acute safety investigation of Caerin 1.9 peptide in Sprague Dawley (SD) rats. The results showed that subcutaneous injection of Caerin 1.9 at 100 mg/kg is safe and does not cause mortality or organ malfunction in the recipient rats. For the consecutive injection of F3 at 10 mg/kg, the peak concentration (Cmax) of F3 displayed at 1 hr after injection in male rats was 591 ng/mL, the average drug retention time was 0.807 hr, T1/2 was 4.58 hr, and AUC0-last was 1890 h × ng/mL. In female rats, Cmax was 256 ng/mL, with an average drug retention time of 2.96 hr, T1/2 of 1.33 hr, and AUC0-last of 740 h × ng/mL. The results showed that the concentration of Caerin 1.9 in the peripheral blood peaked at 1 hour. As injected concentration increased, T1/2 extended, and Cmax, AUC0-last, and volume of distribution at a steady state all increased. After 14 days of repeated subcutaneous injection at 10.0 mg/kg, no accumulation of Caerin 1.9 in plasma was observed. The results of tissue distribution showed that the Caerin 1.9 is below the LC-MS/MS detection threshold at a minimum concentration of 40 ng/g. In conclusion, Caerin 1.9 is well tolerated in rats and could be used with current immunotherapies for better management of solid tumors and genital warts.

A Systematic Review on Synthetic and Antimicrobial Bioactivity of the Multifaceted Hydrazide Derivatives

: To overcome the upsurge of antimicrobial resistance that has emerged in recent years, there is a need for the development of newer hits having satisfying anti-infective activity. Hydrazides incorporated with an azomethine hydrogen account for a cardinal class of molecules for the development of newer derivatives. Hydrazide derivatives have gained considerable interest of medicinal chemists owing to their diverse bioactivity. In the present review, we have attempted to compile the recent trends in the synthesis of hydrazides and their substituted derivatives. The structural features that lead to the desired antimicrobial activity are highlighted, which will lead the way for synthetic and medicinal chemists to focus on newer designs in this arena.