Antimicrobial Activity Research Articles

Underutilized edible Himalayan herb, Viola canescens Wall.; chemical composition, antioxidant and antimicrobial activity against respiratory tract pathogens

Understanding the intricacies of herbs and foods against bacterial infections is paramount for informed therapeutic choices. Delving into this domain, current study was focused to assess antimicrobial properties of Viola canescens organ specific extracts against prevalent respiratory tract pathogens (Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumonia). Our methodology entailed proximate composition, TPC, TFC, Total condensed tannins and comprehensive chemical profiling by GC-MS, UPLC-PDA, and UPLC-MS/MS. Further, in-vitro, antioxidant potential through ABTS ֹ+ and DPPH ֹ radical scavenging assays was assessed. The root showed higher amount of proximate composition than its counterparts. Further, ethanol extract showed highest TPC (32.15±0.92mg GAE/g), TFC (125.61±2.28mg RE/g), and comparable TCT with methanol extract (34±0.19mg CE/g). UPLC analysis showed that p-coumaric acid was most predominant followed by rutin and luteolin among the V. canescens parts. In GC/MS analysis, methyl linoleate emerged as a major component as 10.70%, 17.62%, and 35.90% in flowers, leaves, and roots, respectively. Further, UHPLC- MS/MS data-based METLIN search revealed the presence of flavonoids, coumarins, terpenoids, and fatty acid derivatives etc. Chemo-metric analysis also showed variations of metabolites in different parts. All samples showed significant antioxidant activity with highest in methanol and ethanol flower extracts (0.037±0.001, 0.071±0.001 DPPHֹ and ABTS ֹ + IC50 mg/mL). The study suggested aerial parts can be a promising source of antioxidant and antimicrobial agents that may protect against respiratory tract pathogens similar to azithromycin. This substantiates the potential of V. canescens as a foundational ingredient for novel therapeutics.

Cm-p5, a molluscan-derived antifungal peptide exerts its activity by a membrane surface covering in a non-penetrating mode

Amidst the health crisis caused by the rise of multi-resistant pathogenic microorganisms, Antimicrobial Peptides (AMPs) have emerged as a potential alternative to traditional antibiotics. In this sense, Cm-p5 is an AMP with fungistatic activity against the yeast Candida albicans. Its antimicrobial activity and selectivity have been well characterized; however, the mechanism of action is still unknown. This study used biophysical approaches to gain insight into how this peptide exerts its activity. Stability and fluidity of lipid membrane were explored by liposome leakage and Laurdan generalized polarization (GP) respectively, suggesting that Cm-p5 does not perturb lipid membranes even at very high concentrations (≥100µm.L-1). Likewise, no depolarizing action was observed using 3,3'-propil-2,2'-thyodicarbocianine, a potential membrane fluorescent reporter, with C. albicans cells or the corresponding liposome models. Changes in liposome size were analyzed by Dynamic Light Scattering (DLS) data, indicating that Cm-p5 covers the vesicular surface slightly increasing liposome hydrodynamic size, without liposome rupture. These results were further corroborated with Langmuir monolayer isotherms, where no significant changes in lateral pressure or area per lipid were detected, indicating little or no insertion. Finally, data obtained from molecular dynamics simulations aligned with in vitro observations, whereby Cm-p5 slightly interacted with the fungal membrane model surface without causing significant perturbation. These results suggest Cm-p5 is not a pore-forming anti-fungal peptide and that other mechanisms of action on the membrane as some limitation of fungal nutrition or receptor-dependent transduction for depressing growth development should be explored.

Implementation of Silver Nanoparticles Green Synthesized with Leaf Extract of Coccinia grandis as Antimicrobial Agents Against Head and Neck Infection MDR Pathogens.

Head and neck infections (HNI) associated with multidrug resistance (MDR) offer several health issues on a global scale due to inaccurate diagnosis. This study aimed to identify the bacteria and Candidal isolates and implement the silver nanoparticles green synthesized with leaf extract of Coccinia grandis (Cg-AgNPs) as a therapeutic approach against HNI pathogens. The Cg-AgNPs were characterized by the UV-visible spectrophotometer, FT-IR analysis, Zeta particle size, Zeta potential, and field emission scanning electron microscope (FESEM) analysis to validate the synthesis of nanoparticles. Additionally, the antimicrobial activity of Cg-AgNPs was presented by the zone of inhibition (ZOI), minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and antibiofilm assay. Moreover, the cell wall rupture assay was visualized on SEM for the morphological study of antimicrobial activities, and the in-vivo toxicity was performed in a swiss mice model to evaluate the impact of Cg-AgNPs on various biological parameters. Different bacterial strains (Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and Candida sp. (Candida albicans, Candida tropicalis, Candida orthopsilosis, and Candida glabrata) were identified. The MIC, MBC, and antibiofilm potential of Cg-AgNPs were found to be highest against A. baumannii: 1.25 μg/ml, 5 μg/ml, and 85.01±5.19% respectively. However, C. albicans and C. orthopsilosis revealed 23 mm and 21 mm of ZOI. Subsequently, the micromorphology of the cell wall rupture assay confirmed the efficacy of Cg-AgNPs, and no significant alterations were seen in biochemical and hematological parameters on the swiss mice model in both acute and subacute toxicity studies. The green synthesized Cg-AgNPs have multifunctional activities like antibacterial, anticandidal, and antibiofilm activity with no toxicity and can be introduced against the HNI pathogens.

Biodegradable active films based on Chlorella biomass and cellulose nanocrystals isolated from hemp stalk fibers

Cellulose nanocrystals (CNC)-reinforced biopolymers have emerged as a widely embraced approach for enhancing the characteristics of biopolymers due to their exceptional properties. Biocomposite (Chl-CNC) films were fabricated by blending Chlorella biomass and varying concentrations of CNCs via a solution casting technique. CNCs were effectively isolated from hemp stalk fibers, as confirmed by structural, surface, thermal, and morphological analysis. The crystallinity of films increased by CNC incorporation, which was confirmed by the XRD. The presence of molecular interactions between CNC and protein-rich Chlorella biomass was illustrated with the FTIR analysis. These interactions enhanced the physicochemical properties of the films. Further, films demonstrated a high level of soil biodegradation in the 42 days, while their total phenolic, chlorophyll, carotenoid contents, and antibacterial activity were unaffected by the incorporation of CNCs. The Chl-CNC films, regardless of CNC addition, indicated antimicrobial activity toward Escherichia coli but not Staphylococcus aureus. These results indicate that developed biobased and biodegradable Chl-CNC films could be highly beneficial in active food packaging applications.

PLA/PCL POLYMER NANOCOMPOSITE WITH SILVER AND COPPER NANOPARTICLES AND LAVENDER ESSENTIAL OIL: SYNTHESIS, CHARACTERIZATION AND APPLICATION IN TISSUE ENGINEERING

The present work aims to synthesize, characterize, and evaluate the cytotoxicity and antimicrobial activity of PLA/PCL polymeric nanocomposite with silver nanoparticles (AgNPs) and copper (CuNPs) and the addition of lavender essential oil (LEO) for application in tissue engineering. For the synthesis of the nanocomposite films, the central composite rotational design (CCRD 2²) was used, where the ideal condition was 0.5%wt. of AgNPs and CuNPs (3:1D) with a higher cell viability (196.1%) after 24 hours. After defining the ideal condition, the effect of incorporating LEO into the polymer blend and nanoparticles in the proportions of 0.5 (3:1D0.5), 0.75 (3:1D0.75) and 1 v v-1 (3:1D1) was evaluated. All nanocomposite films were characterized structurally, morphologically, thermally, and mechanically by X-ray diffraction (XRD), Field Emission Gun–Scanning Electron Microscopy (FEG-SEM), Thermogravimetric analysis (TGA), contact angle and mechanical Properties (displacement and maximum tension). To evaluate cytotoxicity, an in vitro safety profile was performed in HFF-1 (fibroblasts) and HaCat (keratinocytes) cell lines, where PLA/PCL polymer blend with 0.5 %wt. of AgNPs and CuNPs (3:1D) and PLA/PCL polymer blend with 0.5 %wt. of AgNPs and CuNPs and LEO (0.5 v v-1) (3:1D0.5) nanocomposite film showed the best cell viability without the nitric oxide (NO) generation, total levels of reactive oxygen species (ROS) or dsDNA release for the HFF-1 and HaCat cell lines, as well as genoprotective characteristic and without genotoxic profile. Moreover, the tests were carried out on the pH of injured skin at different immersion times (3, 6, 12 and 24 hours) and didn´t show cell death or inflammatory reaction. For the antimicrobial activity, the 3:1D, 3:1D0.5, and PLA/PCL polymer blend with 0.5 %wt. of AgNPs and CuNPs and LEO (0.75 v v-1) (3:1D0.75) nanocomposite films showed the formation of biofilm for S. aureus, E. coli, P. aeruginosa and K. pneumoniae. Therefore, the PLA/PCL polymer nanocomposite with AgNPs and CuNPs showed potential application as a healing dressing for skin regeneration.

Apigenin Bioisosteres: Synthesis and Evaluation of their Antioxidant, Antimicrobial, and Anticancer Activities

: A novel series of Apigenin bioisosteres [1(4-chlorophenyl)-3-phenyl prop-2-ene-1-one] non-cyclic derivatives (4a-4c) and [7-hydroxy-2-phenyl-4H-chromen-4-one] cyclic derivatives (9a- 9d) were synthesized. The newly synthesized apigenin bioisosteres were confirmed using UV, IR, NMR, and mass spectroscopic methods. The antioxidant, antibacterial, and anti-cancer activities of all newly synthesized compounds were assessed using the DPPH free radical scavenging capacity, disc diffusion method, and in vitro MTT assay on the human breast cancer MCF-7 cell line. Almost all the synthesized apigenin bioisosteres had greater antioxidant and antimicrobial activity than standard Apigenin. Out of seven compounds (4a-4c and 9a-9d), five compounds were found to exhibit notable antiproliferative activity on the breast cancer cell line (MCF-7), whereas two compounds, 9c and 9d, did not show notable activity. Our analysis suggests that synthesized Apigenin bioisosteres function as prospective antioxidant, antimicrobial, and anticancer agents.

Recent Progress in Isolating and Purifying Amide Alkaloids from their Natural Habitats: A Review

: Alkaloids are nitrogen-containing chemical compounds found in nature. Many alkaloids are heterocyclic in nature. They are nitrogen-based organic compounds with the nitrogen atoms enclosed in a heterocyclic ring. The chemical "pro alkaloid" is derived from the alkyl amines in it. Many ancient people, long before the advent of organic chemistry, recognized that many of these substances have measurable effects on the body's physiological functions. Alkaloids are a type of natural substances that are classified as secondary metabolites. Many different types of organisms create alkaloids, which are a class of natural products. Alkaloids showed antifungal, local anesthetic, anti-inflammatory, anticancer, analgesic, neuropharmacologic, antimicrobial, and many other activities. Amines, as opposed to alkaloids, are the more common classification for naturally occurring compounds that contain nitrogen in the exocyclic position (such as mescaline, serotonin, and dopamine). An amide molecule has a nitrogen atom that is chemically bound to a carbon atom in the carbonyl group. The -oic acid ending of the corresponding carboxylic acid is converted to -amide to form the correct nomenclature for an amide. This article offers an overview of numerous techniques for extracting, separating, and purifying alkaloids for use in natural medicine.

An Overview of Metallic Nanoparticles: Classification, Synthesis, Applications, and their Patents.

Nanotechnology has gained enormous attention in pharmaceutical research. Nanotechnology is used in the development of nanoparticles with sizes ranging from 1-100 nm, with several extraordinary features. Metallic nanoparticles (MNPs) are used in various areas, such as molecular biology, biosensors, bio imaging, biomedical devices, diagnosis, pharmaceuticals, etc., for their specific applications. For this study, we have performed a systematic search and screening of the literature and identified the articles and patents focusing on various physical, chemical, and biological methods for the synthesis of metal nanoparticles and their pharmaceutical applications. A total of 174 references have been included in this present review, of which 23 references for recent patents were included. Then, 29 papers were shortlisted to describe the advantages, disadvantages, and physical and chemical methods for their synthesis, and 28 articles were selected to provide the data for biological methods for the formulation of metal NPs from bacteria, algae, fungi, and plants with their extensive synthetic procedures. Moreover, 27 articles outlined various clinical applications of metal NPs due to their antimicrobial and anticancer activities and their use in drug delivery. Several reviews are available on the synthesis of metal nanoparticles and their pharmaceutical applications. However, this review provides updated research data along with the various methods employed for their development. It also summarizes their various advantages and clinical applications (anticancer, antimicrobial drug delivery, and many others) for various phytoconstituents. The overview of earlier patents by several scientists in the arena of metallic nanoparticle preparation and formulation is also presented. This review will be helpful in increasing the current knowledge and will also inspire to innovation of nanoparticles for the precise and targeted delivery of phytoconstituents for the treatment of several diseases.

Comprehensive analysis of soybean (Glycine max L.) by-products: nutritional value, phenolic composition, and bioactive properties

Soybeans are key components in vegetable beverage production, generating two by-products: soybean hulls and okara. For every ton of soybeans, 50-80 kg of hulls and 120 kg of okara are produced, being often discarded or used in low-value applications like fertilizers or feed. This study aims at characterizing their biochemical and nutritional profiles to assess their potential reintroduction into the food chain. Both by-products have high levels of protein and dietary fiber, mainly insoluble. Okara and hulls predominantly contain oleic acid and linoleic acid, respectively. Seventeen phenolic compounds, mainly isoflavones, were identified, with genistein as the main compound. Hulls exhibit superior antioxidant activity compared to okara. Neither extract showed cytotoxicity or anti-inflammatory effects and exhibited limited antimicrobial activity. However, both demonstrate prebiotic potential, promoting beneficial gut bacteria growth. The results suggest that these by-products have significant potential as new ingredients for their protein, isoflavone, and fiber content, alongside prebiotic properties.

Fighting H. pylori with Medicinal Plants: A Study on Jordan's Traditional Remedies

Aims of the Study: This study was designed to evaluate the antimicrobial activity of some medicinal plants used among Jordanians for the treatment of gastritis and gastric ulcers against H. pylori. Moreover, plants' inhibitory activity against the H. pylori urease enzyme was also evaluated. Materials and Methods: The activity of 11 medicinal plants used by common people and herbalists to treat ulcers was evaluated against H. pylori (NCTC 11916). Ethanol and essential oil extracts from the tested plants were evaluated using a standard agar dilution method and the MICs were determined. Furthermore, the potential inhibitory effect of each preparation was tested against the enzyme urease using a kinetic colorimetric assay. Results: Cinnamomum cassia oil showed the highest efficiency against H. pylori with the lowest MIC (0.0122 mg.mL-1), followed by Origanum syriacum and Foeniculum vulgare (MICs of 0.39 mg.mL-1). Furthermore, significant urease inhibition activity was recorded for Carum carvi oil (IC50~0.45 mg.mL-1). C. cassia oil (IC50 ~2.8 mg.mL-1), Aloysia citriodora, and Artemisia Judaica (IC50 5.8 mg.mL-1) reported potential urease inhibition activities. Conclusion: Herbs used in Jordanian traditional medicine were found to have anti-H. pylori and significant urease inhibitory activity. These findings might support the use of medicinal plants as adjuvant or alternative therapy for the treatment of H. pylori.

Anti-inflammatory and Antimicrobial Potential of 1, 3, 4-oxadiazoles and its Derivatives: A Review.

1, 3, 4-oxadiazole and its derivatives have significant anti-inflammatory and antimicrobial property. Their precise mechanism of action is not known but it is postulated that they act by inhibiting the biosynthesis of certain prostaglandins. 1, 3, 4-oxadiazoles are a class of heterocyclic compounds with wide variety of biological and pharmacological activities. They have been reported to possess analgesic, antimicrobial, antipyretic and anti-inflammatory properties. These compounds are also active against a number of other inflammatory conditions such as arthritis, gout etc. A wide variety of these compounds have been synthesized and some of them are under clinical trials. In this review article, anti-inflammatory and antimicrobial activity of the 1, 3, 4- oxadiazole shall be discussed.

Therapeutic and Health Promoting Potential of Terminalia chebula: An Exploratory Literature Review

: The plant Terminalia chebula has been used traditionally in many regions of the world for its therapeutic properties, especially in India. Its therapeutic and health-promoting potential has been recognized for centuries, and modern research continues to unveil its numerous benefits. One of the most significant applications of this plant is its antimicrobial and antioxidant potential. The plant contains high levels of phenolic compounds and flavonoids, which scavenge harmful free radicals in the body, reducing oxidative stress and cellular damage. This antioxidant action contributes to its anti-inflammatory effects, making it beneficial for a wide range of conditions, including arthritis, cardiovascular diseases, and neurodegenerative disorders. Furthermore, Terminalia chebula exhibits antimicrobial activity against various bacteria and fungi, including those responsible for common infections. It has been used to treat respiratory infections, urinary tract infections, and skin ailments. Its broad-spectrum antimicrobial effects make it a valuable natural remedy for combating microbial pathogens. Moreover, Terminalia chebula shows potential in managing diabetes and promoting cardiovascular health. Studies have indicated its ability to regulate blood sugar levels, improve insulin sensitivity, and reduce lipid abnormalities. These properties make it a promising adjunct therapy for individuals with diabetes or at risk of heart disease. In conclusion, Terminalia chebula possesses remarkable therapeutic and health-promoting potential. Its antioxidant, anti-inflammatory, antimicrobial, and digestive benefits make it a valuable natural remedy for various ailments. While research on Terminalia chebula is ongoing, its long-standing use in traditional medicine and emerging scientific evidence solidify its status as a potent medicinal plant with diverse applications in promoting overall well-being.

Phytochemical screening and in vitro antimicrobial activity of Rosmarinus officinalis leaves

Rosmarinus officinalis is a medicinal plant, which belongs to family Lamiaceae. It is an evergreen bush. It was analyzed for its phytochemical constitution and antibacterial activity. For this purpose, leaves of n-hexane, ethyl acetate and methanolic extracts were used. The tests of phytochemical screening showed that the plant leaves contain anthraquinones, terpenoids, flavonoids, reducing sugars, saponins, cardiac glycosides, coumarins, phenols, carbohydrates, proteins, steroids, alkaloids and quinones, while tannin was absent. The antibacterial activity was determined against E. coli and staphylococcus aureus; the invitro antibacterial activity was performed by disc diffusion method. The n-hexane and ethyl acetate extracts showed no antibacterial activity against E. coli while ethyl acetate extracts showed antibacterial activity against Staphylococcus sp. The results showed that the highest mean inhibition zone was observed in the methanolic extracts.

Structure-based design and synthesis of (E)-l-(s-pheny1)-N-(4-(2,2,4-trimethy1-2,3-dihydro-lH-benzo[b][l,4]diazepin-l-yl)phenyl)methanimine motifs as antimicrobial and anti-tubercular agents

Benzodiazepines' chemistry and synthesis as heterocyclic compounds have recently attracted a lot of attention, due to their extensive biological diversity in drug design and potential for usage in agrochemicals. Eco-friendly and highly efficient method was herein reported for the synthesis of a new series of Schiff base of benzodiazepine derivatives 3a-l using microwave-assisted approach. Firstly, 2,2,4-trimethy1-2,3-dihydro-lH-benzo[b][l,4]diazepine (1) was synthesized by AgNO3-catalyzed reaction of o-phenylenediamine with excess of acetone. Coupling of benzodiazepine 1 with 4-chloroaniline afforded intermediate benzodiazepine 2 which was subsequently reacted with benzaldehyde derivatives via microwave irradiation technique to access twelve final targeted benzodiazepine Schiff bases, 3a-l. The chemical structures of the scaffolds 3a-l were authenticated using analytical and spectroscopic data. Benzodiazepine Schiff bases 3a-l were investigated for their in vitro antimicrobial activities using Agar diffusion technique and screened for their minimum inhibitory concentration (MIC) using microtube dilution technique. Ten pathogenic organisms comprising of seven bacterial and three fungal isolates were utilized for the screening. Ciprofloxacin was the positive control for antibacterial screening while fluconazole was engaged as the positive control for the antifungal screening. The most efficacious antimicrobial agent among the series was (E)-l-(2-Chloropheny1)-N-(4-(2,2,4-trimethyl-2,3-dihydro-lH-benzo[b][l,4] diazepinlyl)phenyl)methanimi ne (3b) with a MIC value of 3.13 µg/mL and MBC of 6.25 µg/mL among all the synthesized compounds synthesized and screening for antimicrobial assessment. Compound 3b also emerged as the best anti-tubercular agent IC50 of 40 µg/mL against Mycobacterium tuberculosis, Mycobacterium bovis and H37Rv

Eucalyptus globulus essential oil as food preservative: Chemical composition, antimicrobial (in vitro and in situ), antibiofilm and insecticidal potential

The use of species within the Eucalyptus genus has been widespread in traditional medicine practices globally. However, concerns regarding safety and toxicity data have been prominent due to the extensive use of its essential oil, which is widely regarded for its medicinal properties and various applications. This research aimed to analyze the chemical makeup of Eucalyptus globulus essential oil (EGEO) and explore its antibacterial and insecticidal properties both in laboratory settings and real-life scenarios. Gas chromatography/mass spectrometry (GC/MS) was employed to identify the chemical constituents of EGEO, revealing 1,8-cineole (86.1 %), ο-Cymene (4.9 %), α-Pinene (3.8 %), γ-Terpinene (2.2 %), and α-Terpinene (1.6 %) as the primary components. The disc diffusion method demonstrated EGEOʼs strongest antimicrobial activity against Micrococcus luteus (p < 0.05), while minimal inhibition concentration tests indicated notable effectiveness against Streptococcus pneumoniae (MIC50 2.25 mg/mL and MIC90 2.79 mg/mL). In situ antibacterial assessments using white radish and pear food models showed heightened activity compared to contact application, particularly with the highest concentration (500 µg/L), yielding optimal results against Pseudomonas putida (p < 0.05). Additionally, the study investigated EGEO's antibiofilm properties against Salmonella enterica using mass spectrometry and the crystal violet method. In terms of insecticidal action, EGEO at 100 % concentration resulted in the mortality of 90 % of Harmonia axyridis individuals. This comprehensive investigation contributes to a deeper understanding of both the chemical composition and biological activities of Eucalyptus globulus essential oil, highlighting its potential as a source of natural compounds with promising therapeutic properties.

Synthesis and Biological Evaluation of Amino Acid and Peptide Conjugates of 5-Bromovaleric Acid.

Among various carboxylic acid derivatives, valeric acid or pentanoic acid is found to be widely distributed in nature. It is a straight-chain alkyl carboxylic acid containing five carbon atoms. Due to the therapeutic value of valeric acid, it is used as a versatile nucleus in the pharmaceutical field. Valeric acid derivatives are associated with a broad spectrum of biological activities, like anticonvulsant, antiplatelet, antidiabetic, and plant growth activities. It has previously been revealed that peptide derivatives of carboxylic acids are accountable for enhanced antimicrobial activity. Therefore, it was hypothesized that coupling peptides with valeric acid would increase the antimicrobial properties of the target compounds. So, the objective of the present study was to synthesize peptide derivatives of 5-bromovaleric acid and evaluate their antibacterial and antifungal activities. 5-bromovaleric acid was synthesized by the reaction of cyclopentanone and hydrogen peroxide in the presence of copper bromide and sodium bromide. Additionally, 5-bromovaleric acid was coupled with amino acid methyl esters, dipeptides, tripeptides, and tetrapeptides in the presence of dicyclohexylcarbodimide (DCC) and N-methylmorpholine (NMM) as a base under continuous stirring for 36 hours to produce its peptide derivatives. The results obtained showed that 5-bromovaleric acid possesses more potent antibacterial activity than N-terminal 5-bromovaleric acid conjugates of selected di-, tri, and tetra peptide Cterminal methyl esters against ciprofloxacin as a standard. The selected dipeptide and tripeptide Nterminal 5-bromovaleric acid-conjugated C-terminal methyl ester derivatives were more active than the selected tetrapeptide methyl ester analogue. Using fluconazole as a reference, the antifungal efficacy of 5-bromovaleric acid against C. albicans and A. niger declined as it was combined with C-terminal methyl esters of selected dipeptides, tripeptides, and tetrapeptides. The novel selected peptide derivatives had less antibacterial and antifungal action than the parent 5-bromovaleric acid. Antibacterial and antifungal investigations showed that 5- bromopentanoic acid peptide derivatives might impair antimicrobial efficacy. Further, attaching 5- bromopentanoic acid to di, tri, and tetra peptides did not boost their antibacterial potential.

Effect of ozone gassing time and stirring duration on peroxide value, microbial decontamination, aflatoxin detoxification and sensorial characteristics of dried pistachios

Aflatoxin contamination in agricultural products such as pistachios threatens human health. Ozone has intense antimicrobial activity against microorganisms. The effect of ozone-treated time (3,4 and 5 hours) and stirring time (10, 15 and 20 minutes) on microbial, aflatoxin content, peroxide value, and sensory properties of aflatoxin contaminated pistachios were investigated in this study. The microbial test results also show a significant reduction of microbial load in ozone-treated samples. According to the results, ozone gas caused a significant reduction in aflatoxin levels in pistachio kernels. Aflatoxins B1, B2, G1, G2 and total which was 33.5, 1.5, 0.06, 0. 31 and 35.13 ppb in the control sample, reached 0 ppb after 5 hours of ozone-treatment (15 or 20 min). The results show that the longer the ozone gas is gasified, the higher the peroxide value. The lowest and highest peroxide value was observed in the control and the ozone-treated sample for 5 hours (stirring the samples every 20 minutes), respectively. All peroxide values were below the allowable limit (1 meq/kg). The results of sensory evaluation show that ozonation did not have a negative effect on the falvor, texture, and color score of pistachios, but only had a significant effect on the aroma of pistachios that were ozone-treated for 5 hours. According to results, 3 hours of ozonation and stirring of pistachios every 20 minutes is recommended as the best treatment for reducing microbial load, aflatoxin content, peroxide value and maintaining the sensory properties of dried pistachios.

Self-assembling into nanostructure of Cu-Ag NPs with both enhanced antimicrobial activity and cytocompatibility

Self-assembling into nanostructure of Cu-Ag NPs with both enhanced antimicrobial activity and cytocompatibility

Fabrication, characterisation, physicochemical and biological studies of gelatin/PVA/ silk fibre with manganese substituted hydroxyapatite scaffold for bone tissue engineering application

In recent years, researchers have been aiming for the development of multifunctional materials to repair bone tissue. The development of metal, ceramic, glass, and composite implants is the subject of interest in bone tissue engineering. Among these, HAP (ceramic) is either combined with other components, such as polymers or doped with ions to give improved properties or to add novel characteristics. The present study is focused on fabricating a novel scaffold with the required properties. Here gelatin/PVA/SF-Mn-HAP (MGPS) was fabricated by electrospinning to prepare a nano-level scaffold. The manganese-hydroxyapatite (Mn-HAP) was prepared by hydrothermal method. The nano scaffold was fabricated using various wt % (20, 40, 60) of Mn-HAP (Ca5-x Mnx (PO4)3 OH) (x = 0.1, 0.5) with gelatin/PVA/silk fibre. The fabricated nano scaffold phase formation was confirmed by X-ray diffraction (XRD), the functional group belonging to the nano scaffold was confirmed by Fourier transform infrared spectroscopy (FTIR), the topography of the nano scaffold was seen by scanning electron microscopy and the composition of elements was noted from energy dispersive X-ray analysis (EDAX). From the results, the fabricated scaffold MGPS 16 (60 wt% of Mn-HAP (x = 0.5 M) with gelatin-PVA-silk fibre) showed the highest tensile strength of 95.61 MPa. The antimicrobial activity of MGPS 16 showed the zone of inhibition against S. aureus – 62 ± 1.36 mm,E. coli – 71 ± 1.24 mm and C. albicans – 70 ± 1.22 mm. The hemolytic (%) of the MGPS 16 was 1.86 %. The SEM images of biomineralized samples showed the formation of apatite on the surface of the nano-composite.

Optimization of chitosan-gelatin-based 3D-printed scaffolds for tissue engineering and drug delivery applications

The combination of biocompatible materials and advanced three-dimensional (3D) additive manufacturing technologies holds great potential in the development of finely tuned complex scaffolds with reproducible macro- and micro-structural characteristics for biomedical applications, such as tissue engineering and drug delivery. In this study, biocompatible printable inks based on chitosan, collagen and gelatin were developed and 3D-printed with a pneumatic-based extrusion printer. The printability of various chitosan–gelatin (CS-Gel) hydrogel inks was assessed by evaluating the quality of the printed constructs. The inks required an extrusion pressure of 150 ± 40 MPa with G22 and G25 nozzles for optimal printing. Inks with low chitosan concentrations (<4% w/v) exhibited poor printability, while inks with 4 % w/v chitosan and 1 % w/v gelatin (CG) demonstrated satisfactory extrusion and printing quality. The addition of collagen (0.1 % w/v) to the optimized ink (CGC) did not compromise printability. Post-printing stabilization using KOH produced self-supporting scaffolds with consistent morphological integrity, while weaker bases like NaOH/EtOH and ammonia vapors resulted in lower pore sizes and reduced structural stability. Water evaporation studies showed that neutralized samples had slower evaporation rates due to the strong intermolecular interactions formed during the neutralization process, contributing to a stable crosslinked network. FTIR spectra confirmed the formation of polyelectrolyte complexes in the CS-Gel and CS-Gel-Collagen blends, further enhancing structural stability. Swelling tests indicated that neutralized constructs maintained stability in different pH environments, with KOH-treated samples exhibiting the lowest swelling ratios and the highest structural stability. After optimizing the ink composition, 10 wt% Levofloxacin was loaded in the constructs as a model antibiotic and it’s in vitro release rate was quantified. Drug loading was approximately 4 % for both ink compositions GC and CGC. CG Levo released over 80 % of levofloxacin within the first hour, reaching full release in 24 h, indicating inadequate control, while CGK Levo exhibited slower initial release (55 % in 15 min) followed by stabilized release after 4 h, likely due to controlled diffusion from expanded constructs. These findings demonstrate that the developed hydrogel inks and optimized printing parameters can produce scaffolds suitable for tissue engineering applications. Finally, the cell compatibility of the 3D-printed constructs was confirmed with MTT assay on fibroblasts and the antimicrobial activity of the drug-loaded constructs was tested against E. coli and S. aureus, showing an increase of the bacteria free zone from 8 ± 0.4 mm of the control against E. coli up to 16.4 ± 0.37 mm in the presence of the KOH-treated CG Levo printed construct.