Natural Antimicrobials Research Articles

A potential antifungal bioproduct for Microsporum canis: Bee venom.

Natural treatment options forMicrosporum canisdermatophytosis are being explored because of resistance to several antifungal medications. In this study, the potential antifungal effect of bee venom (BV), a natural antimicrobial agent, onM. caniswas investigated. The antifungal effects of BV, fluconazole, itraconazole, amphotericin B and terbinafine were evaluated by the macrodilution method at various concentrations by modifying the microdilution method recommended by the European Committee on Antimicrobial Susceptibility Testing. All isolates were observed to be susceptible to terbinafine and fully resistant to fluconazole and amphotericin B. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values ofM. canisisolate 2 (Mc2) were determined as 8 µg/mL for itraconazole. The MIC and MFC values of BV were found to be 320 µg/mL for the Mc2 isolate and 640 µg/mL for the Mc6 isolate. The results showed that the isolates obtained from clinical samples in this study were highly resistant to all antifungal agents, except terbinafine. The increase in resistance indicates that antifungal drugs will become insufficient and ineffective over time and natural products such as BV should be evaluated as alternatives.Contribution:Although there are many drugs for the treatment ofM. canis, the increase in resistance to antifungal agents reveals the need for the identification and development of new natural agents. Bee venom, which has been shown to have a safe and weak allergenic effect in various studies, can be tested for usability as a local antifungal drug when supported byin vivostudies.

Evaluating the Health Implications of Kombucha Fermented with Gardenia jasminoides Teas: A Comprehensive Analysis of Antioxidant, Antimicrobial, and Cytotoxic Properties

Background/Objectives: Plant-derived compounds are increasingly valued in drug discovery for their therapeutic potential. This study aims to examine the antimicrobial, antioxidant, and anticancer properties of kombucha beverages fermented with Gardenia jasminoides (GJ) and various types of Camellia sinensis teas: matcha green tea (MGT), organic green tea (OGT), and decaffeinated green tea (DGT). Methods: Two experimental designs were employed: (1) using black tea as a base substrate, infusing the four teas post-fermentation over 0–14 days, and (2) directly fermenting tea–herb combinations over 0–21 days. Antioxidant activity was assessed via the DPPH assay. Microbial dynamics were analyzed through total mesophilic bacteria and Lactobacillus counts. Antimicrobial potential was evaluated against E. coli, S. aureus, and S. enteritidis over 24 h. Cytotoxicity assays were conducted on Caco-2 and U251 cell lines to assess anticancer effects, with pH-adjusted controls used to differentiate bioactivity from acidity. Results: In the first experiment, GJ kombucha displayed the highest antioxidant potential (IC50: 14.04 µg/mL), followed by MGT (IC50: 32.85 µg/mL) and OGT (IC50: 98.21 µg/mL). In the second setup, unfermented GJ kombucha initially showed high antioxidant activity (IC50: 12.94 µg/mL), improving during fermentation to reach an IC50 of 18.26 µg/mL by day 21. Microbial analysis indicated moderate increases in total mesophilic bacteria and Lactobacillus in GJ kombucha after 14 days, while MGT, OGT, and DGT exhibited higher increments. GJ kombucha consistently demonstrated the highest antimicrobial activity against E. coli, S. aureus, and S. enteritidis, with significant inhibitory effects observed by 24 h. Cytotoxicity assays showed that GJ kombucha reduced Caco-2 cell viability to 20% at 800 µg/mL after 14 days, while U251 cells maintained 50% viability at the same concentration. Conclusions: This study highlights the antimicrobial, antioxidant, and anticancer potential of GJ kombucha, with fermentation enhancing bioactive metabolite production. Optimizing fermentation conditions, identifying specific bioactive compounds, expanding cytotoxicity testing, and exploring broader therapeutic applications of kombucha could maximize its health benefits and establish it as a natural antimicrobial and anticancer agent.

Essential Oils as Potential Natural Antioxidants, Antimicrobial, and Antifungal Agents in Active Food Packaging

In the last few years, there has been growing interest in the harmful impact of synthetic additives, the increased consumer focus on nutrition, and their unwillingness to use antibiotics and preservatives. The food industry has been driven to seek natural alternatives to synthetic antioxidants and integrate them into the production processes. Moreover, the most significant risk factor for foodborne illness is the consumption of raw or undercooked meats and milk, which may be contaminated with Listeria spp., Campylobacter spp., or Salmonella spp. This article presents a review of techniques for the functional properties of biopolymer particles loaded with essential oils that form a stable network to control their release, making them ideal for improving food packaging and processing. Such substances are employed in the manufacture of packaging materials and coated films and as emulsions, nanoemulsions, and coatings directly incorporated into the food matrix. It is of paramount importance to gain an understanding of the migration mechanism and potential interactions between packaging materials and foodstuffs. A more profound comprehension of the chemical constitution and biological characteristics of these extracts and their constituents would be advantageous for the identification of prospective applications in active food packaging. The findings of our study suggest the existence of certain constraints and deficiencies in the investigation of essential oils and their efficacy in food packaging. Consequently, further comprehensive research in this domain is imperative.

Plant Species with Antimicrobial Effects and the Importance of a Standardization of Protocols for Antimicrobial Agents

In modern times, microbial resistance is a global threat to health and development. The misuse and inappropriate use of antimicrobials is the main cause of developing drugresistant pathogens. It requires multiple areas in direction to attain sustainable advance goals. As a result of microbial resistance, the necessity for costly medications and expenses are obstructed worldwide. Due to rising attention in the research of new antimicrobial medicaments from a variety of natural or synthetic sources to fight microbial resistance. Thus, natural antimicrobial agents have been used to a great extent nowadays because plant-derived antimicrobial agents are considered to be safer alternatives for health as compared to those synthetic antimicrobial agents. Overall, the active ingredients, water, essential oils, and ethanolic extracts from selected plants and the mixture of a variety of these natural extracts have been used for centuries, because they possess antimicrobial activity which inhibits the growth of microbes. Natural plants as an antimicrobial agent, like extracts of Curcuma longa L., Piper nigrum L., Vachellia leucophloea, Eclipta prostrata, Ocimum sanctum L., Terminalia arjuna, Manihot esculenta Crantz, Lawsonia inermis L., Zingiber officinale Roscoe, Camellia sinensis (L.) Kuntze, Coriandrum sativum L., Carica papaya L., Cinnamomum tamala, and many others have been preferred and used for ages because they are easily available worldwide. They are usually of low cost and have little or no side effects. Several antimicrobial screening approaches like the disk-diffusion method, well diffusion method, micro broth dilution assay, sterile disk method, and agar diffusion method are generally cast off for measurement of reproducibility and standardization of these antimicrobial agents. This review article is a comprehensive description of natural plants like Coriandrum sativum L., Carica papaya L., Cinnamomum tamala, etc., containing those extracts used as antimicrobial agents listed, and numerous in vitro antimicrobial susceptibility testing methods are reported. These identified plant species and antimicrobial screening techniques hold the potential for formulating these plants into antimicrobial drugs, warranting further study and exploration in the field of medicine.

Usnic acid brief exposure suppresses cariogenic properties and complexity of Streptococcus mutans biofilms

Bacterial biofilms are highly structured surface associated architecture of micro-colonies, which are strongly bonded with the exopolymeric matrix of their own synthesis. These exopolymeric substances, mainly exopolysaccharides (EPS) initially assist the bacterial adhesion and finally form a bridge over the microcolonies to protect them from environmental assaults and antimicrobial exposure. Bacterial cells in dental biofilm metabolize dietary carbohydrates and produce organic acids. The blanket of exopolysaccharides over the bacterial communities hinders the buffering by saliva, contributing to the initiation of tooth decay followed by the progression of dental caries. Considering the current interest towards the use of natural antimicrobial agents to disarm the cariogenic properties of dental biofilm, this study evaluated the antimicrobial activity and the effect of twice daily brief exposure (1 min) of usnic acid on acid production, acid tolerance and development of 3-dimensional architecture of Streptococcus mutans biofilm. Herein, biofilms were briefly treated twice daily during biofilm development and biofilms were analyzed by using biochemical, microbiological and microscopic examination. Results obtained in this study showed a significant reduction in virulence properties of biofilm cells treated with usnic acid in compared to non-treated biofilms. Furthermore, twice daily brief exposure of usnic acid significantly disrupted the acid production and reduced the complexity of Streptococcus mutans biofilm by disrupting the EPS production. Brief exposure of usnic acid inhibited the production of glucosyltransferase (GTF) enzymes and their enzymatic activity leading to inhibition in production of EPS on the biofilm matrix. In conclusion, usnic acid treatment reduced the cariogenic properties and complexity of S. mutans biofilm by inhibiting acid production, acid tolerance and disrupting extracellular polysaccharide (EPS) formation, indicating its potential for preventing dental caries.

Impact of phytoceuticals: Thymol-loaded zein-based nano-antimicrobials to combat resistant zoonotic pathogen

Campylobacter jejuni related gastrointestinal infections are challenging to overcome due to emerging antimicrobial resistance that poses global public health concerns. The development of biopolymeric nanosystems encapsulating natural antimicrobials serves as an alternative-medicine based on phytoceuticals. Thymol, an essential ingredient extracted from the thyme plant (Thymus vulgaris), and oregano plant (Origanum vulgare) exhibits a wide range of applications including anti-inflammatory, antibacterial, and antioxidant properties. However, its bioavailability, low stability, and poor water solubility severely limit its applications. Herein, zein nanosystems encapsulating thymol (TH-ZNs) were successfully fabricated to enhance the antibacterial and antibiofilm potential of thymol against foodborne multidrug-resistant C. jejuni. Through the antisolvent precipitation technique, physically stable nanosystems were obtained exhibiting a high encapsulation efficiency of 87 ± 0.5 %. Scanning electron microscopy revealed slightly rough surface morphology of TH-ZNs. FTIR spectroscopy elucidated hydrophobic interactions between thymol and zein which facilitates the successful encapsulation of thymol. Dynamic light scattering (DLS) studies revealed that the entrapment of thymol in ZNs increased the size from 202 ± 1.4 nm to 212 ± 1 nm, whereas zeta potential values were reduced from −42 ± 3 mV to −37 ± 2 mV in the case of void and TH-ZNs, respectively. Furthermore, TH-ZNs exhibited higher antimicrobial and antibiofilm efficacy against C. jejuni as compared to free thymol for a longer period. These results indicate that TH-ZNs inhibited bacterial growth while being non-cytotoxic, thus improving the overall efficiency of phytoceuticals to develop alternative nanotherapeutics to combat the resistant zoonotic pathogen.

Review on Melanin Application as an Antibacterial and Antioxidant Agent in Food Packaging

One of the solutions to reduce food waste is creating innovative food packaging to lengthen its shelf life. This type of packaging can be produced by incorporating natural antimicrobials and antioxidation agents such as melanin. Various biologically active and multifunctional properties are associated with this biomacromolecule, i.e., antioxidants, antibacterial properties, and free radical scavengers. Thus, melanin is an indispensable component. It is expected that food packaging manufactured from natural materials containing melanin will have several advantages, including biodegradability, antioxidant ability, and antibacterial activity. A review of melanin as an antibacterial and antioxidant agent from many different sources that is utilized as an additive in food packaging is presented.

Antibacterial effects of Psidium guajava leaf extracts on diarrhea caused by Salmonella typhimurium and Escherichia coli in sheep

Diarrhea in neonatal ruminants, especially sheep, poses a serious challenge in livestock management, often leading to high mortality rates. The primary pathogens responsible are Salmonella typhimurium and Escherichia coli. This study explores the antibacterial potential of Psidium guajava (guava) leaf extracts as an alternative to conventional treatments. Guava leaves, collected from Tubah subdivision, Mezam, were processed into aqueous and ethanolic extracts. Phytochemical analysis revealed the presence of bioactive compounds including resins, alkaloids, saponins, glycosides, tannins, and flavonoids. Antibacterial activity was assessed using agar well diffusion and Minimum Inhibitory Concentration (MIC) methods. The aqueous extract displayed dose-dependent antibacterial effects, with inhibition zones of 16.0 mm against E. coli and 15.2 mm against S. typhimurium at 100 mg/ml, which were less effective compared to Gentamycin (19 mm). The MIC values for the aqueous extract were 6.25–3.13 mg/ml for E. coli and 12.5–6.25 mg/ml for S. Typhimurium. In contrast, the ethanolic extract showed slightly superior efficacy with inhibition zones of 16.2 mm for E. coli and 17.6 mm for S. Typhimurium at 100 mg/ml. The MIC values for the ethanolic extract were 3.13–1.56 mg/ml for E. coli and 6.25–3.13 mg/ml for S. typhimurium, indicating higher potency than the aqueous extract. Conclusively, both guava leaf extracts exhibit significant antibacterial properties, with the ethanolic extract being more potent. These results validate the traditional use of Psidium guajava and suggest its potential as a natural antimicrobial agent, though further research is needed to optimize its therapeutic applications.

Cinnamaldehyde in Focus: Antimicrobial Properties, Biosynthetic Pathway, and Industrial Applications.

Trans-cinnamaldehyde (TCA), a major bioactive compound derived from cinnamon (Cinnamomum spp.), has garnered significant attention for its diverse therapeutic properties. Its broad-spectrum antimicrobial activity, targeting both Gram-positive and Gram-negative bacteria as well as various fungi, positions TCA as a potent natural antimicrobial agent. Beyond its antimicrobial effects, TCA demonstrates promising antidiabetic and anti-inflammatory activities, making it a valuable compound in medicinal and cosmetic applications. Recent studies have highlighted its role in disrupting microbial membranes, inhibiting biofilm formation, and modulating key metabolic pathways in pathogens. Furthermore, TCA has gained popularity in cosmetics due to its antimicrobial activity, antioxidant properties, and skin-friendly profile. This review provides a comprehensive overview of TCA's antimicrobial potential, focusing on its mechanisms of action and its market and industrial applications. We also discuss the biosynthetic pathway of TCA, exploring both its natural production in cinnamon and advances in biotechnological production methods. As the demand for sustainable and natural antimicrobial agents grows, TCA emerges as a promising candidate for diverse applications. Finally, this review explores future directions for optimizing TCA production through metabolic engineering and synthetic biology approaches to meet industrial-scale demands.

Exploring the Antibacterial Properties and Chemical Profiles of Essential Oils from Syzygium aromaticum and Nigella sativa Against MDR Bacteria

For centuries, plants have been studied for their healing properties. Recently, the rise of antibiotic resistance in bacteria has prompted scientists to explore herbal remedies. Syzygium aromaticum, from the Myrtaceae family, has been utilized as a histological clearing agent. In contrast, Nigella sativa (black cumin), a member of the Ranunculaceae family, has long been utilized in traditional medicine dating back to ancient times. The current study investigates the chemical composition and antibacterial activity of essential oils from Syzygium aromaticum (clove) and Nigella sativa (black cumin) against multidrug-resistant (MDR) bacteria. Using the agar well diffusion method, Syzygium aromaticum exhibited significant antibacterial activity, particularly against Salmonella typhi (30.66 mm inhibition zone), while Nigella sativa was effective only against Staphylococcus aureus (19 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for Syzygium aromaticum ranged from 3.53 to 7.06 mg/mL, indicating stronger antibacterial properties than Nigella sativa (MIC: 12.7 mg/mL, MBC: 22.5 mg/mL). GC-MS analysis revealed that Syzygium aromaticum contained bioactive compounds like Diglycolic acid (76.59%) and Eugenol (2.06%), while Nigella sativa was dominated by Heptasiloxane (80.83%) and Thymoquinone (2.66%). These findings suggest that Syzygium aromaticum essential oil could serve as a potent natural antimicrobial agent against MDR pathogens.

Chemical Composition, Biological Activity, and Application of Rosa damascena Essential Oil as an Antimicrobial Agent in Minimally Processed Eggplant Inoculated with Salmonella enterica.

Rosa damascena is mostly grown for its usage in the food, medical, and perfume industries, while it is also used as an attractive plant in parks, gardens, and homes. The use of R. damascena essential oil may yield new results in relation to the antimicrobial activity of essential oils and their use mainly in extending the shelf life of foods. This study investigates the chemical composition and antimicrobial properties of Rosa damascena essential oil (RDEO) using gas chromatography-mass spectrometry (GC-MS) and various bioassays to explore its potential applications in food preservation and microorganism growth control. The GC-MS analysis revealed that RDEO is predominantly composed of phenylethyl alcohol (70%), which is known for its antimicrobial and aromatic properties. Additionally, other significant constituents were identified, including nerol, citronellol, and geraniol, which may contribute to the EOs overall bioactivity. The antimicrobial activity was assessed through the minimal inhibition concentration against five Candida yeast strains, four Gram-positive, and four Gram-negative bacteria, including biofilm-forming Salmonella enterica. Determination of minimum inhibitory concentrations (MIC) revealed the strongest effects of RDEO's on Gram-negative species, with MIC50 values as low as 0.250 mg/mL for S. enterica. Moreover, an in situ assessment utilizing fruit and vegetable models demonstrated that the vapor phase of RDEO significantly suppressed microbial growth, with the most substantial reductions observed on kiwi and banana models. As a result of our study, the antimicrobial effect of RDEO on the microbiota of sous vide processed eggplant was detected, as well as an inhibitory effect on S. enterica during storage. The insecticidal activity against Megabruchidius dorsalis Fahreus, 1839, was also studied in this work and the best insecticidal activity was found at the highest concentrations. These results suggest that RDEO has the potential to serve as a natural antimicrobial agent in food preservation and safety applications, providing an alternative to synthetic preservatives.

Mechanistic Investigation of the Pyrolysis Temperature of Reed Wood Vinegar for Maximising the Antibacterial Activity of Escherichia coli and Its Inhibitory Activity.

To solve the problem of large-scale growth of wetland reeds, wood vinegar, a by-product of pyrolysed reed wood vinegar, can be used as a natural antimicrobial agent. In this study, we compare the changes in growth and bacterial morphology of Escherichia coli (E. coli) treated with reed wood vinegar at different pyrolysis temperatures (300 °C, 500 °C and 700 °C) and reveal the bacterial inhibition mechanism of reed wood vinegar by RNA-Seq. The results of bacteria inhibitory activity showed that 1/2MIC 500 °C wood vinegar had the most prominent bacteria inhibitory activity. qPCR results showed that reed wood vinegar was able to significantly inhibit the expression of E. coli biofilm and genes related to the cell membrane transporter proteins. Electron microscopy observed that the wood vinegar disrupted the cellular morphology of E. coli, resulting in the crumpling of E. coli cell membranes. RNA-Seq showed the multifaceted antimicrobial effects of wood vinegar and demonstrated that the inhibitory effect of wood vinegar on E. coli was mainly realized through the inhibition of the expression of malE, which is an ATP-binding cassette (ABC) transporter complex of E. coli. In conclusion, our study provides an effective method and a theoretical basis for the mechanism of reed wood vinegar as a natural antimicrobial agent and its pathway of bacterial inhibition.

Evaluation of Biological Activities of Various Extracts of Glaucium alakirensis, Marrubium bourgaei, and Peucedanum alpinum from Türkiye

Plant species contain many secondary metabolites, and these compounds differ from species to species. These differences in the concentrations of these compounds have many health implications. Today, studies on plants' antioxidant and antibacterial effects are gaining importance. In particular, the adverse effects of some existing antibiotics and the constant development of bacterial resistance are leading to the search for new natural antimicrobial agents. In this study, methanol, ethanol, ethyl acetate, acetone, and chloroform extracts were obtained from the aerial parts of Marrubium bourgaei Boiss and Glaucium alakirensis Aykurt, K.Yıldız & A.Özçandır, and Peucedanum alpinum B.L.Burtt & Davis, species which are naturally distributed in Türkiye. The antioxidant activity of the extracts was determined by the DPPH (2,2 Difenil-1-pikrihidrazil) and ABTS (2,2' azino-bis(3-ethylbenz-thiazoline-6-sulfonic-acid)) methods, the total phenolic content by Folin-Ciocalteu method, the total flavonoid content by aluminium chloride colorimetric method, and the antibacterial activity against ten bacteria by the disc diffusion method. According to the results, methanol, ethanol, and acetone extracts had higher antioxidant activity, total phenolic, and total flavonoid contents than other extracts. However, the total flavonoid content of M. bourgaei was higher in the ethyl acetate extract. When evaluated for their antibacterial activity, ethanol, chloroform, and ethyl acetate in P. alpinum, chloroform in M. bourgaei, and methanol, chloroform, and ethyl acetate in G. alakirensis extracts showed antibacterial activity against more bacteria than others. This is the first study to evaluate and compare the total phenolic and flavonoid content, and antioxidant and antibacterial activities of 5 different extracts of these plants.

Antimicrobial and antioxidant study of combined essential oils of Anethum Sowa Kurz. and Trachyspermum ammi (L.) along with quality determination, comparative histo-anatomical features, GC‒MS and HPTLC chemometrics

Spices played crucial and variable roles in traditions, culture, history, religious ceremonials and festivals along with fetching food flavor and microbial protection globally due to presence of structurally unique and multi-natured chemotypes. Their existence in dishes portrayed key roles in improving shelf life by regulating spoilage of cuisine with different synergistic mechanism. Histo-anatomically (A) sowa exhibited distinguished cellular attributes which created remarkable differences with T. ammi. HPTLC chemometrics of both fruits revealed several peaks for active metabolomics with unique isocratic combination of menstruum. GC-MS study of hydro-distillate exhibited presence of monoterpenic cyclic and aromatic hydrocarbons, alcoholic and ketonic groups along with phenolic derivative that covers majorly 90% of total metabolites. Combined essential oils (EOs 1 + 2) of both fruits showed excellent antimicrobial activity against various clinical pathogenic strains such as K. pneumoniae at 10 µL/mL, S. aureus at 2.5 µL/mL, E. coli and E. faecalis at 1.25 µL/mL, and MRSA and Bcereus at 0.625 µL/mL and (C) albicans at 0.312 µL/mL as the MIC. The antioxidant study of (EOs 1 + 2) with maximum inhibition percentage to DPPH assay was 84.02 ± 1.05 at 100 µg/mL, and minimal inhibition was 72.31 ± 0.63 at 5 µg/mL with IC50 value 4.69 ± 0.22 µg/mL, while ABTS assay extreme was 79.15 ± 2.14 µg/mL and minimal was 67 ± 1.34 with the IC50 value of 18.37 ± 0.15 µg/mL, in superoxide assay uppermost inhibition was 81.03 ± 0.27 µg/mL and lowest was at 65.16 ± 3.15 with the IC50 value 16.46 ± 0.54, and H2O2 radical scavenging activity, predominant value was 78.01 ± 0.47 and least was 64.1 ± 2.01 with IC50 15.58 ± 0.34. These comparative key diagnostic features and synergistic effect of multicomponent natural antimicrobials will provide profound intellect of ancient utility and further scientists to explore their multiple mechanistic modality and application in food and beverages industry.

A Comprehensive Review of the Antimicrobial Effects of Hibiscus Species.

Hibiscus, particularly Hibiscus sabdariffa, is a flowering plant known for its bright red calyxes and diverse uses in traditional medicine. Historically, cultures throughout Africa, Asia, and the Caribbean have utilized hibiscus for its health benefits, including its role in treating high blood pressure, digestive problems, and skin conditions. The rich phytochemical profile of hibiscus, particularly its high content of anthocyanins and flavonoids, has attracted increasing scientific interest, particularly with regard to its antimicrobial properties. Research shows that hibiscus extracts possess significant antimicrobial activities against various pathogens, including bacteria such as Escherichia coli and Staphylococcus aureus and fungi such as Candida albicans. The active ingredients in hibiscus are believed to disrupt microbial membranes, inhibit enzyme activity, and effectively scavenge free radicals, thereby exerting a broad spectrum of antimicrobial effects. The promising antimicrobial properties of hibiscus suggest numerous potential applications, particularly in food preservation, natural antimicrobial agents, and adjunctive therapies for infection control. Future research should focus on elucidating the specific mechanisms of action, optimizing extraction methods for maximum effectiveness, and conducting clinical trials to validate effectiveness in different settings. Additionally, exploring the inclusion of hibiscus in health products, such as wound dressings and topical treatments, could open up new avenues for natural health solutions. Overall, hibiscus represents a valuable opportunity to advance antimicrobial strategies in a world increasingly wary of antibiotic resistance.

Unveiling the antibacterial and antioxidant capabilities of Diospyros buxifolia leaf and stem extracts via GC-MS analysis

Drug-resistant microorganisms pose a significant threat to public health as they can undermine the effectiveness of existing antibiotics and other medications. Additionally, the formation of free radicals, can contribute to various health problems. Diospyros buxifolia (D. buxifolia) belonging to Ebenaceae family is a large tropical evergreen tree utilised in traditional medicine to cure several health ailments. The present study was set out to separate bioactive speciation of aqueous and methanolic extracts of stem and leaves from D. buxifolia by using Gas Chromatography-Mass Spectrometry (GC-MS) followed by evaluation of its antimicrobial and antioxidant capabilities. GC-MS identified 14 different bioactive compounds, with four compounds common for both (leaf and stem) extracts. The methanolic extracts of leaf demonstrated significant antibacterial activity) while stem extracts exhibited notable antioxidant potential. Thus, D. buxifolia is proved source of natural antimicrobial and antioxidant agent, that could address the challenges posed by drug-resistant microorganisms and oxidative stress in global health.

Green Synthesis, Structural Insights, and Antimicrobial Potential of Zinc Oxide Nanoparticles Synthesized via Sustainable Method

Background: Green synthesized nanoparticles have gained wide interest in today’s world due to their inherent features like rapidity, eco-friendliness, and costeffectiveness [4].In this study, zinc oxide (ZnO) nanoparticles were synthesized using an aqueous extract of Ixora coccinea leaves. X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) studies were used to analyze the structural and morphological properties of prepared Zinc Oxide nanoparticles. Methods: The sol-gel method of synthesis via the green route was introduced to synthesize pure Zinc oxide nanoparticles. Silver-doped Zinc Oxide nanoparticles were also prepared using the same method Result: The XRD studies showed the crystalline nature and revealed the purity of Zinc Oxide nanoparticles. The specific functional groups responsible for reduction, stabilization, and capping agents present in the nanoparticles were examined using Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. The bacterial destruction was better for ZnO nanoparticles than reported for plant extracts and standard drugs. Conclusion: This study proves that Zinc Oxide nanoparticles contain natural antimicrobial agents through green synthesis, which may serve to produce drugs for antimicrobial therapeutics.

Nano-power: Unveiling the antimicrobial potency of nutmeg seed extract nanoemulsions

This study investigates the antimicrobial effects of nutmeg seed extract nanoemulsion on Staphylococcus aureus and Escherichia coli. The nanoemulsion was prepared using the oil-in-water method and modified spontaneous emulsification, resulting in a stable formulation with 3% (v/v) nutmeg extract and nonionic surfactants. GC-MS analysis identified 42 bioactive compounds, including fatty acids, esters, and aromatic compounds, known for their antimicrobial, antifungal, and antioxidant properties. FESEM and EDX Mapping confirmed a stable, spherical morphology with particle sizes below 100 nm, with NEp 3% averaging 31 nm and NEp 5% averaging 54 nm. The antimicrobial efficacy tests revealed significant inhibition zones, particularly highlighting hexadecanoic acid, ethyl ester as a key antimicrobial agent. The NEp 3% nanoemulsion demonstrated superior activity against S. aureus due to its smaller particle size, while the NEp 5% showed reduced efficacy, likely due to larger particle sizes. This study underscores the rich chemical composition and significant antimicrobial activity of nutmeg seed powder extract in a nanoemulsion form, particularly against S. aureus. Future research could explore its broader applications as a natural antimicrobial agent in industries such as food preservation, healthcare, and cosmetics.

Activity of Bambara Groundnut Seed Coat Extract Against Shewanella Species: Efficacy and Mechanisms of Action.

The Bambara groundnut is the indigenous legume in the southern part of Thailand. It contains a seed coat rich in polyphenols, which can serve as natural antimicrobial agents. The extracts from red and white seed coats of Bambara groundnuts, namely RSC and WSC, respectively, were prepared using an ultrasound-assisted extraction process. The extraction yield, total phenolic content (TPC), and antimicrobial activity of both extracts were examined. The RSC extract demonstrated a significantly higher extraction yield (8.35%) than WSC extract (2.34%) (p < 0.05). Furthermore, the TPC of RSC extract (420.98 ± 0.27 mg of gallic acid/g dry extract) was higher than that of WSC extract (28.29 ± 0.91 mg of gallic acid/g dry extract). The RSC extract exhibited stronger inhibition against Shewanella putrefaciens and S. algae than its WSC counterpart. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) analysis indicated that the RSC extract was rich in flavonoids and polyphenols, while the WSC extract contained more triterpenoid saponins. Time-kill kinetics showed that the RSC extract reduced bacterial loads in a dose-dependent manner. Scanning electron microscopic images revealed that drastic bacterial cell membrane damage with a rough surface and the deformation of cells was caused by the extract. Furthermore, confocal laser scanning microscopic (CLSM) images confirmed the inhibition of S. algae biofilm formation by RSC extract. RSC extract also suppressed bacterial motility, induced protein leakage, and reduced extracellular protease activity, thus highlighting its potent bactericidal effects. These findings suggested that the RSC extract rich in phenolic compounds could serve as an antimicrobial agent and hold promise as a natural preservative for perishable foods, especially seafoods.

Natural Antimicrobial Agents from Algae: Current Advances and Future Directions.

Infectious diseases have significantly shaped human history, leading to significant advancements in medical science. The discovery and development of antibiotics represented a critical breakthrough, but the rise of antibiotic-resistant pathogens now presents a serious global health threat. Due to the limitations of current synthetic antimicrobials, such as toxicity and environmental concerns, it is essential to explore alternative solutions. Algae, particularly microalgae and cyanobacteria, have emerged as promising sources of bioactive antimicrobial compounds. This review provides a comprehensive analysis of the antimicrobial properties of algal-derived compounds, including polysaccharides, fatty acids, and phenols, which have shown effectiveness against multi-drug-resistant bacteria. A co-occurrence bibliometric analysis using VOSviewer highlighted five key research clusters: antibiotic resistance, algal extracts, biosynthesis, water treatment, and novel pharmacological compounds. Furthermore, the primary mechanisms of action of these bioactive compounds, such as the inhibition of protein synthesis and cell membrane disruption, were identified, demonstrating their potential against both common and multi-resistant pathogens. Future research should prioritize optimizing algal biomass production, utilizing genetic and metabolic engineering, and creating innovative delivery systems to enhance the efficient production of bioactive compounds.