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ODREĐIVANJE FARMAKOLOŠKE AKTIVNOSTI SINTETSKIH BOJA NA BAZI PIRIDONA
No full textAzo dyes are known as structurally diverse class of organic compounds bearing one or more
azo groups (–N=N–) as a bridge between organic residues of which at least one is an aromatic moiety. This group of synthetic dyes is obtained easily by the reaction of diazo coupling with high yield. The importance of azo dyes is reflected in the fact that they account for 60 % of the total number of the dye structures known to be manufactured and used in the coloration of textiles, leather, plastics and cosmetics. Aside from their traditional usage, azo dyes are known for their therapeutic properties and wide range of applications in biomedicine and pharmaceutical industry. Hereby, the present study aims to investigate the relationship between the chemical structure and pharmacological activity of four azo pyridone dyes taking into account the tautomeric form of dyes. The relationship was determined empirically using appropriate software packages as well as in vitro using the 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The results of in silico prediction suggested that all investigated compounds possess good oral bioavailability, while the results of the ABTS assay indicate poor to excellent antioxidant activity depending on the substituent in the phenyl ring. Considering the broad applications of arylazo pyridone dyes, as well as the fact that their relative importance may increase in the future, results obtained in this study serve as a basis for further investigations.Azo boje predstavljaju strukturno najraznovrsniju klasu organskih jedinjenja koja sadrže jednu
ili više azo grupa (–N=N–) koje premošćavaju dva organska motiva od kojih je bar jedan aromatičan.
Ova grupa sintetskih boja dobija se jednostavnom sintezom koja uključuje reakciju diazo-kuplovanja u
visokom prinosu. Da su azo boje od neprocenjivog značaja u različitim granama industrije gde se primenjuju za nijansiranje tekstila, kože, plastike i kozmetičkih proizvoda, govori i činjenica da su zastupljene sa preko 60%. Pored tradicionalne primene, azo boje su poznate i po sve većoj upotrebu u biomedicini i farmaceutskoj industriji. Na osnovu navedeneg, cilj ovog rada je da se detaljnije ispita veza
između hemijske strukture četiri azo piridonske boje i njihove farmakološke aktivnosti uzimajući u obzir
tautomerni oblik boje. Ova veza određena je empirijski korišćenjem odgovarajućih softverskih paketa
kao i in vitro određivanjem njihove antioksidativne aktivnosti primenom ABTS metode. Rezultati in
silico predikcije pokazuju da sva ispitivana jedinjenja poseduju dobru oralnu bioraspoloživost i nisku
do odličnu antioksidativnu aktivnost u zavisnosti od spupsptituenta u fenilnom jezgru. Uzimajući u obzir
širok spektar primene arilazo piridonskih boja kao i činjenicu da će njihov značaj konstantno rasti,
rezultati ostvareni u ovom radu predstavljaju interesantnu osnovu za buduća istraživanja
Improvement of Alginate Extraction from Brown Seaweed (Laminaria digitata L.) and Valorization of Its Remaining Ethanolic Fraction
No full textThis study aimed to improve the conventional procedure of alginate isolation from the brown seaweed (Laminaria digitata L.) biomass and investigate the possibility of further valorization of the ethanolic fraction representing the byproduct after the degreasing and depigmentation of biomass. The acid treatment of biomass supported by ultrasound was modeled and optimized regarding the alginate yield using a response surface methodology based on the Box–Behnken design. A treatment time of 30 min, a liquid-to-solid ratio of 30 mL/g, and a treatment temperature of 47 °C were proposed as optimal conditions under which the alginate yield related to the mass of dry biomass was 30.9%. The use of ultrasonic radiation significantly reduced the time required for the acid treatment of biomass by about 4 to 24 times compared to other available conventional procedures. The isolated alginate had an M/G ratio of 1.08, which indicates a greater presence of M-blocks in its structure and the possibility of forming a soft and elastic hydrogel with its use. The chemical composition of the ethanolic fraction including total antioxidant content (293 mg gallic acid equivalent/g dry weight), total flavonoid content (14.9 mg rutin equivalent/g dry weight), contents of macroelements (the highest content of sodium, 106.59 mg/g dry weight), and microelement content (the highest content of boron, 198.84 mg/g dry weight) was determined, and the identification of bioactive compounds was carried out. The results of ultra high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry analysis confirmed the presence of 48 compounds, of which 41 compounds were identified as sugar alcohol, phenolic compounds, and lipids. According to the 2,2-diphenyl-1-picrylhydrazyl assay, the radical scavenging activity of the ethanolic fraction (the half-maximal inhibitory concentration of 42.84 ± 0.81 μg/mL) indicated its strong activity, which was almost the same as in the case of the positive control, synthetic antioxidant butylhydroxytoluene (the half-maximal inhibitory concentration of 36.61 ± 0.79 μg/mL). Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus) were more sensitive to the ethanolic fraction compared to Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei). The obtained results indicated the possibility of the further use of the ethanolic fraction as a fertilizer for plant growth in different species and antifouling agents, applicable in aquaculture
Exploring the antimicrobial and antioxidant potential of bacterial cellulose-cerium oxide nanoparticles hydrogel: Design, characterization and biomedical properties
No full textBacterial cellulose (BC) is a promising natural polymer prized for its biocompatibility, microporosity, transparency, conformability, elasticity, and ability to maintain a moist wound environment while absorbing exudates. These attributes make BC an attractive material in biomedical applications, particularly in skin tissue repair. However, its lack of inherent antimicrobial activity limits its effectiveness. In this study, BC was enhanced by incorporating cerium (IV)-oxide (CeO2) nanoparticles, resulting in a series of bacterial cellulose-CeO2 (BC-CeO2) composite materials. Characterization via FESEM, XRD, and FTIR confirmed the successful synthesis of the composites. Notably, BC-CeO2-1 exhibited no cytotoxic or genotoxic effects on peripheral blood lymphocytes, and it additionally protected cells from genotoxic and cytotoxic effects in H2O2-treated cultures. Redox parameters in blood plasma samples displayed concentration and time-dependent trends in PAB and LPP assays. The incorporation of CeO2 nanoparticles also bolstered antimicrobial activity, expanding the potential biomedical applications of these composites
Continuous Drive Friction Welded Al/Cu Joints Produced Using Short Welding Time, Elevated Rotational Speed, and High Welding Pressures
No full textThe present study aimed to enhance the efficiency and efficacy of the Al/Cu joint productionprocess implemented by the company VEMID Ltd., Jagodina, Serbia, by attaining sound joints withina very short welding time. For this purpose, the present study aimed at investigating the accuracyand the quality of the continuous drive friction welding (CDFW) process, as well as the optimumcombination of CDFW parameters with highest joint efficiency in terms of investigated properties.The accuracy was estimated through an analysis of temperature–time curves recorded during CDFWusing an infrared camera. The quality was evaluated through an investigation of the properties ofAl/Cu joints produced using different friction (66.7, 88.9, and 133.3 MPa) and forging (88.9, 222.2,and 355.6 MPa) pressures and a constant total welding time (4 s) and rotational speed (2100 rpm).Thermal imaging with an infrared camera demonstrated that the actual total welding time was 15%longer compared to the nominal value. This was attributed to the slow pressure response of thepneumatic brake system. The relative changes in the maximum surface temperature (TMS) during theCDFW process corresponded to changes in welding pressures, indicating the potential of the thermalimaging method for monitoring and assessing this process. A preliminary investigation demonstratedthat Al/Cu joints produced using welding pressures less than 88.9 MPa often displayed the presenceof non-joined micro-regions at the Al/Cu interface and a significant thickness of interfacial Al2Cu (upto 1 µm). However, when friction pressure was set at 66.7 MPa, an increase in the forging pressure to222.2 MPa eliminated the presence of non-joined micro-regions and reduced the thickness of Al2Cuto 0.5 µm on the average level. These Al/Cu joints achieved the highest joint efficiencies in terms ofstrength (100%) and ductility (61%). They exhibited an electrical conductivity higher than 92% ofthe theoretical value. A further increase in any welding pressure produced similar or deterioratedproperties, accompanied by an increase in the consumption of raw materials and energy. Such turnof events was counterproductive to the original goal of increasing the efficiency and efficacy of theCDFW process
Electrospun Pullulan/Hemp Protein Nanohybrids for Sustained Release of Phenylethanoid Glycosides
No full textInnovative electrospun pullulan/hemp protein isolate nanofibers (PUL/HP) with lecithin were successfully formulated for the delivery of phenylethanoid glycosides (PGs) from Teucrium montanum extract, at PUL to HP ratios of 80:20, 70:30, 60:40, 50:50, 40:60, and 30:70, based on total polymer mass (w/w). A higher HP content led to a more elastic behavior, which was stimulated by a stronger entanglement between polymer and polypeptide chains. The biopolymers used showed favorable compatibility with the investigated PGs, achieving an encapsulation efficiency of over 80 %. The increased elastic behavior led to the formation of a bead-on-string morphology and a higher average diameter. The thermal stability of the loaded nanofibers was diminished by the presence of incorporated polyphenolic extract. Under simulated gastrointestinal conditions, a sustained release of total phenolic content from the delivery systems was achieved. According to the FTIR spectra, this is mainly due to the efficient interplay of hydrogen and hydrophobic interactions with the polyphenols within the polysaccharide-phospholipid-polypeptide structure. The circular dichroism spectra showed that the polyphenol extract was involved in the secondary HP structure, resulting in a rather random, uncoiled structure. These results provide a time- and cost-efficient approach to stabilize naturally immiscible biopolymers without crosslinking or emulsion preparation, while similarly altering the physicochemical properties of the drug delivery systems
Cold plasma/alkaline pretreatment facilitates corn stalk fractionation and valorization towards zero-waste approach
No full textThe present study employed alkaline hydrogen peroxide pretreatment coupled with cold plasma for corn stalk’s complex biopolymers fractionation and valorization through enzymatic hydrolysis. This hurdle approach enables the prolonged generation of reactive oxidative species, initiating chemical reactions otherwise hardly possible under ambient conditions. A delignification rate between 76±1 and 86±2 % was obtained under different process parameters in a significantly shorter time compared to conventional alkaline pretreatment. Up to 94±4 % of cellulose in treated biomass was converted to glucose after enzymatic hydrolysis, achieving around 3.5 times higher glucose yield than the raw biomass. Different spectroscopic analyses confirmed specific alterations in the structure of the lignin-rich fraction caused by cold plasma. Micro- and nanoscale lignin particles obtained were rich in total phenolic content, reaching up to 140±20 and 107±12 µg gallic acid equivalents (GAE) per mg of lignin, respectively. The proposed concept of corn stalk fractionation through biorefinery can open new opportunities for valorizing different agricultural waste types.This is the peer-reviewed version of the following article: Grbić, J. Z., Mladenović, D. D., Veljković, M. B., Lazarević, S. S., Lević, S. M., Lazović, S. S.,& Đukić-Vuković, A. P.. (2024). Cold plasma/alkaline pretreatment facilitates corn stalk fractionation and valorization towards zero-waste approach. in Industrial Crops and Products. 2024;222: 119498. [https://doi.org/10.1016/j.indcrop.2024.119498]Published version: [https://technorep.tmf.bg.ac.rs/handle/123456789/7609
Harnessing the Potential of Amniotic Membrane Homogenate: A Novel Bioink for 3D Bioprinting in Breast Reconstruction
No full textINTRODUCTION Despite their safety and feasibility for patients, existing breast reconstruction techniques
post mastectomy carry the risk of potential complications, and do not significantly alter the likelihood of disease recurrence compared to mastectomy alone. The field of tissue engineering has been intensively growing
primarily focusing on crafting diverse scaffolds that act as templates for tissue regeneration. Human amniotic membrane (hAM) of the placenta has been utilized in skin and cornea regeneration, and numerous studies have demonstrated its antitumor, antifibrotic, anti-inflammatory, and immunomodulatory properties.
Here we aim to develop the scaffold biomaterial for 3D bioprinting using human AM homogenate (hAM-h)
that will preserve and exhibit its regenerative and antitumor effects over an extended period when applied
Antibacterial electrospun poly(ε-caprolactone) nanofiber mats loaded with cefazolin and meropenem for wound healing
No full textNanofiber wound dressings represent a promising approach to wound care, offering an
adaptable platform for promoting faster and more effective wound healing. The goal of this
research was the development of poly(ε-caprolactone) (PCL) nanofiber mats with incorporated
antibiotics cefazolin (CEF) and meropenem (MER) for wound healing treatments.
Nanofiber mats based on PCL (8 wt.% PCL prepared in 2,2,2-trifluoroethanol (TFE)) with
cefazolin or meropenem (10 % of the polymer's weight) were produced using the blend
electrospinning method. For comparison, PCL nanofibers without antibiotics were prepared by
dissolving PCL pellets in TFE. The electrospinning parameters were a flow rate of 2.7 ml/h for
PCL/CEF and 3 ml/h for neat PCL and PCL/MER solutions. The distance from the collector was
10 cm, and the voltage was 29 kV for all solutions.
In the processed samples, cefazolin and meropenem maintained their biological activity and
did not react with the PCL. The drug release profiles showed that the PCL/CEF released about
60 % of the drug, while the PCL/MER released about 40 % after 48 hours of incubation in
Mueller-Hinton broth. Both PCL/CEF and PCL/MER nanofiber mats showed similar growth
delays of Gram-positive clinical strains (S. aureus and S. epidermidis) compared to neat PCL.
However, PCL/MER nanofiber mats efficiently inhibited the growth of Gram-negative clinical
strains (E. coli, Klebsiella, Enterobacter spp., and Acinetobacter spp.). The effective antibacterial
action of PCL/MER nanofiber mats could minimize infection-related inflammation, reducing
the risk of complications like delayed healing, sepsis, and chronic wound formation.
The overall results of this study have shown that novel PCL nanofiber mats could be used as a
relevant drug scaffold, keeping the wound infection-free and promoting faster and more
effective tissue repair
Sustainable dyeing of the fabrics by using azo pyridone dyes with improved water solubility
No full textColored effluents from the textile industry contribute significantly to water pollution, posing a serious environmental challenge. Reducing water pollution is a key focus in the EU's goal of achieving climate neutrality by 2050. In line with this, the idea of reusing the same dyebath for multiple dyeing cycles in textile industry is suggested. Therefore, in this study, two azo pyridone dyes with enhanced water solubility are synthesized, fully characterized and used for dyeing fabrics of different chemical compositions. Firstly, the affinity of dyes towards different fabrics is screened by using multifiber fabric, and thereafter individual fabrics are dyed following the principles of sustainable dyeing. The fabrics dyed in each cycle are further analyzed for color strength. The results demonstrate the feasibility of reusing the same dyebath up to four times, significantly reducing the concentration of synthetic dye in the final wastewater