Rapid fabrication of micro-nanofibers from grapevine leaf extract and gelatine via electroblowing: A novel approach for edible active food packaging

The objective of this study was to develop novel micro-nanofibers for food packaging using grapevine extract (GLP) and gelatine using electroblowing technique. The identified components of GLP were dominated by the flavone group phenolics, as analyzed by LC-MS/MS. SBS was used to fabricate gelatine micro-nanofiber mats loaded with three different concentrations of GLP, which were subsequently cross-linked. The micro-nanofibers were characterized by their morphology, chemistry, thermal properties, and bioactivity. The in-vitro antioxidant and antimicrobial effects of the nanofiber mats were determined using various methods, which showed an increase in effectiveness with increasing GLP concentration. The in-situ assessment, where the nanofibers were applied to cheese, also showed a consistent improvement in shelf life with the use of GLP-loaded gelatin electroblown fibers.

Emergence of Nano-Based Formulations for Effective Delivery of Flavonoids against Topical Infectious Disorders

Flavonoids are hydroxylated phenolic substances in vegetables, fruits, flowers, seeds, wine, tea, nuts, propolis, and honey. They belong to a versatile category of natural polyphenolic compounds. Their biological function depends on various factors such as their chemical structure, degree of hydroxylation, degree of polymerization conjugation, and substitutions. Flavonoids have gained considerable attention among researchers, as they show a wide range of pharmacological activities, including coronary heart disease prevention, antioxidative, hepatoprotective, anti-inflammatory, free-radical scavenging, anticancer, and anti-atherosclerotic activities. Plants synthesize flavonoid compounds in response to pathogen attacks, and these compounds exhibit potent antimicrobial (antibacterial, antifungal, and antiviral) activity against a wide range of pathogenic microorganisms. However, certain antibacterial flavonoids have the ability to selectively target the cell wall of bacteria and inhibit virulence factors, including biofilm formation. Moreover, some flavonoids are known to reverse antibiotic resistance and enhance the efficacy of existing antibiotic drugs. However, due to their poor solubility in water, flavonoids have limited oral bioavailability. They are quickly metabolized in the gastrointestinal region, which limits their ability to prevent and treat various disorders. The integration of flavonoids into nanomedicine constitutes a viable strategy for achieving efficient cutaneous delivery owing to their favorable encapsulation capacity and diminished toxicity. The utilization of nanoparticles or nanoformulations facilitates drug delivery by targeting the drug to the specific site of action and exhibits excellent physicochemical stability.

Fabrication of Biohybrid Nanofibers by the Green Electrospinning Technique and Their Antibacterial Activity

The development of bioactive polymer nanofiber sheets based on eco-friendly components is required to meet the needs of various medical applications as well as to preserve the environment. This study aimed to fabricate biohybrid nanofibers based on water-soluble polymers and aqueous extract of myrrh. The myrrh extract was incorporated into poly(vinyl alcohol)/tragacanth gum nanofiber mats (myrrh@PVA/TG) by the green electrospinning technique. Various characteristics of the prepared fibers such as morphology, fiber diameter distribution, crystallinity, and thermal stability were studied. The results confirmed that the morphology of biohybrid nanofibers was uniform without beads and tragacanth gum plays an important role in controlling the average diameter of fibers and the crystallinity. The antibacterial properties of the developed biohybrid nanofibers were investigated against common pathogens of Gram-positive and Gram-negative bacteria by the standard disc diffusion method. A significant antibacterial activity was observed toward bacterial strains after incorporation of aqueous myrrh extract into nanofibers, which increased on increasing the extract ratio. Due to their eco-friendly components and significant antibacterial activity, the prepared biohybrid nanofibers will open new avenues toward incorporating aqueous herbal extracts into degradable polymer fibers for use in many antibacterial applications.

Antimicrobial materials produced by incorporating copper acetate into ethylene-vinyl alcohol copolymer for its use in personal care and cosmetic packaging

Currently, there is a great demand for functional materials with effective pathogen-killing properties. In this research, we describe the use of green technology “reactive extrusion” for the synthesis of potent antimicrobial materials based on Ethylene-vinyl alcohol copolymer (EVOH). Herein, the antimicrobial agent, copper (II) acetate was used without pretreatment and introduced into the EVOH matrices at high temperatures. The thermal reaction of copper (II) acetate within the EVOH matrices and their effect on the thermal and thermomechanical properties of the polymer were investigated in regards to their concentration. The physicochemical, thermal, and rheological features, as well as, metal salt release kinetics were reported. The antimicrobial agent had significant effects on the properties of the matrix. Results showed a reduction in the glass transition temperatures and storage modulus of the materials in response to the incorporation of copper (II) acetate. Finally, the antimicrobial activity of the products was studied and demonstrated a possibility to create antimicrobial materials in a one-step, solvent-free extrusion process.

Co-electrospun nanofibrous mats loaded with bitter gourd (Momordica charantia) extract as the wound dressing materials: in vitro and in vivo study

BACKGROUND

Interactive dressings are innovatively designed to interact with the wound surface and alter the wound environment to promote wound healing. In the current study, we integrated the physicochemical properties of Poly (caprolactone)/ Poly (vinyl alcohol)/Collagen (PCL/PVA/Col) nanofibers with the biological activities of Momordica charantia pulp extract to develop an efficient wound dressing. The electrospinning method was applied to fabricate the nanofibers, and the prepared wound dressings were thoroughly characterized.

RESULTS

SEM imaging showed that the nanofibers were uniform, straight, without any beds with a diameter in the range of 260 to 480 nm. Increasing the concentration of the extract increased the diameter of the nanofibers and also the wettability characteristics while reduced the ultimate tensile strength from 4.37 ± 0.90 MPa for PCL/PVA/Col to 1.62 ± 0.50 MPa for PCL/PVA/Col/Ex 10% (p < 0.05). The in vivo studies showed that the application of the wound dressings significantly enhanced the healing process and the highest wound closure, 94.01 ± 8.12%, was obtained by PCL/PVA/Col/Ex 10% nanofibers (p < 0.05).

CONCLUSION

The incorporation of the extract had no significant effects on nanofibers' porosity, water vapor permeability, and swelling characteristics. The in vitro evaluations showed that the fabricated nanofibers were hemocompatible, cytocompatible, and prevent bacterial penetration through the dressing. These findings implied that the PCL/PVA/Col/Ex nanofibers can be applied as the wound dressing materials.

Antioxidant and Antimicrobial Screening of Isolated Alkaloids from <i>Tinospora crispa</i>

The antioxidant capacity by DPPH radical scavenging and antimicrobial activity by disk diffusion and broth microdilution method of nine isolated alkaloids from T. crispa were evaluated. All isolated alkaloids had been divided into three groups which were aporphine alkaloids, N-formylannonaine (1), N-formylnornuciferine (2), magnoflorine (9), oxoaporphine alkaloids, lysicamine (3) and liriodenine (4); and protoberberine alkaloids, columbamine(6), dihydrodiscretamine (7) and 4,13-dihydroxy-2,8,9-trimethoxydibenzo [a,g]quinolizinium (8). Protoberberine alkaloids showed (IC50 > 500-800 μg/mL) radical scavenging activity while oxaporphine alkaloids inhibited the growth of the Gram-positive bacteria, Staphylococcus aureus (+) and Enterococcus faecalis (+).The antioxidant and antimicrobial properties of different compounds support documented traditional use of T. crispa in wound healing and treatment of rheumatic, diarrhoea, ulcers, itches and wounds. Results of the present biological activity investigation further points to the potential of this plant species as a good source of natural antioxidant and preservative in food industry.

Nanotechnologies: An Innovative Tool to Release Natural Extracts with Antimicrobial Properties

Site-Specific release of active molecules with antimicrobial activity spurred the interest in the development of innovative polymeric nanocarriers. In the preparation of polymeric devices, nanotechnologies usually overcome the inconvenience frequently related to other synthetic strategies. High performing nanocarriers were synthesized using a wide range of starting polymer structures, with tailored features and great chemical versatility. Over the last decade, many antimicrobial substances originating from plants, herbs, and agro-food waste by-products were deeply investigated, significantly catching the interest of the scientific community. In this review, the most innovative strategies to synthesize nanodevices able to release antimicrobial natural extracts were discussed. In this regard, the properties and structure of the starting polymers, either synthetic or natural, as well as the antimicrobial activity of the biomolecules were deeply investigated, outlining the right combination able to inhibit pathogens in specific biological compartments.