Antioxidant Activity of Grapefruit (Citrus Paradisi) Extract

Citrus fruits are widely consumed around the world and among them grapefruit (Citrus paradisi macfad) stands out with its characteristic appearance and flavor. The fruit is growing on a tree that belongs to Rutaceae family and its positive contribution to health is attributed to phytochemicals found in it. The phytochemicals have the key role in mediating oxidation process because they act as antioxidants and by that prevention of cell damage, reducing the risks of many diseases, boosting of the immune system, balancing hormone levels, and notable antibacterial and antiviral response of the organism happens. Grapefruits contain several phytochemicals including: carotenoids, flavonoids (naringin), limonoids, organic acids, pectin, and folate. Considering the worldwide consumption and popularity in everyday diet of grapefruit, the antioxidant activity of its extracts is determined in this paper. Weighed amount 10 g of fresh grapefruits was added to a mixture consisting of organic solvents (hexane, acetone, and ethanol in volumes ratio 2:1:1, respectively) and 0.05% (w/v) butylated hydroxytoluene. The mixture was stoppered and mixed on an orbital shaker at 180 rpm for 15 minutes. The temperature during the mixing was kept at 5 °C in the water bath. Afterward, 7.5 ml of cold deionized water on every 10 grams of starting sample was added to the mixture and agitated for another 5 min. The suspension was transferred to a separation funnel to separate the upper (non-polar) from the lower (polar) phase for 10 minutes at room temperature. The polar phase was subjected for antioxidant capacity determination by ABTS, DPPH, FRAP and CUPRAC methods. The results for the applied methods expressed per kg of the sample are: 1.8 mmol∙kg-1, 0.72 mmol∙kg-1, 9.7 μmol∙kg-1, 4.66 mmol∙kg-1, respectively. The obtained results are recommending grapefruit as a potent source of phytochemicals with antioxidant properties.15th International symposium „Novel technologies and sustainable development", October 20-21 2023, Leskovac

Carotenoid and flavonoid levels, antioxidant activity and antimicrobial properties of tomato grown in Serbia

This work provides an insight into the nutritional quality of Hector-F1 tomato (Solanum lycopersicum L.) fruit grown in Serbia and the juice prepared from it regarding the contents of carotenoids, flavonoids and polyphenols as compounds beneficial for a healthy diet. Initially, ultra-high performance liquid chromatography with electrospray ionization mass spectrometry (UHPLC-ESI-MS) was employed for both polar and non-polar tomato extracts to identify compounds present in the samples. Then, lycopene, β-carotene, total polyphenols and flavonoids contents were determined by means of ultraviolet-visible (UV-Vis) spectrophotometry. To evaluate the antioxidant activity of the samples, four methods were applied, namely, the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method, 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, the ferric ion reducing antioxidant power (FRAP) method and the cupric ion reducing antioxidant capacity (CUPRAC) method. In addition, the antimicrobial potential was tested against gram-positive bacteria, gram-negative bacteria and the yeast Candida albicans. The thermal treatment in all cases modified the chemical composition of tomato as demonstrated by a decrease in values of all measured parameters. This comprehensive analysis provided data applicable to profiling and comparing cultivars grown in different geographical regions. © 2022 National Agricultural and Food Centre (Slovakia)

Synthesis, chemical characterization, and antimicrobial potency of picolinate-based halfsandwich Ru(II) complexes

Eleven new and three reported half-sandwich Ru(II) arene complexes were synthesized using [Ru(g6-benzene)Cl(l-Cl)]2 and [Ru(g6-toluene)Cl(l-Cl)]2 and four pyridine carboxylic acid-based ligands (dicarboxylic acids and halogen derivatives). The structures and purity of synthesized compounds were confirmed using 1H and 13C NMR spectroscopy, infrared spectroscopy, mass spectrometry, and elemental analysis. The stability of synthesized compounds in dimethyl sulfoxide solution was confirmed using 1H NMR spectroscopy. The seven ligands, two complex precursors (CP1 and CP2), and 14 half-sandwich Ru(II) picolinate complexes (C1–C14) were evaluated for in vitro antibacterial and antifungal activity against pathogens, such as Staphylococcus aureus, Bacillus cereus, Proteus mirabilis, Klebsiella pneumoniae, Ecsherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Enterobacter aerogenes, and yeast Candida albicans, using the microwell-dilution method. Among the tested samples, the ligands showed better inhibitory effect against Gram-positive bacteria when compared to the metal complexes. The most susceptible Gram-negative bacteria was Ecsherichia coli, with a MIC value of 1.25 mg/mL, for C3, C6, and C10. All synthesized complexes showed similar, slightly better activity against Candida albicans

Antimicrobial Properties of Silver-Modified Denture Base Resins

The surface quality of denture base resins allows for easy colonization by microorganisms including Candida albicans and Staphylococcus aureus, which cause major diseases of the oral cavity such as denture stomatitis. The widespread use of silver nanoparticles (AgNPs) in various fields of medicine has led to research of their possible application in dentistry, mostly in the prevention of bacterial adhesion, proliferation, and biofilm formation. The aim of the study was to synthesize cold and heat-curing denture base resins modified with AgNPs and AgCl, and evaluate the potential of the modified resins to reduce the growth of C. albicans and S.aureus. The produced material was characterized by Fourier transform infrared spectroscopy (FTIR). The antimicrobial potential of the modified material was demonstrated by the disc-diffusion method, microdilution method, and a modified microdilution method (i.e., disk-diffusion method in broth with viable counting). Spectroscopy confirmed the incorporation of biocidal materials into the structure of the denture base resins. The AgCl and AgNPs modified resins showed an antimicrobial effect. The significance of the study is in the potential therapeutic effects of the modified materials for prevention and threating staphylococci and candida in elderly patients, who are in most cases denture wearers and have a greater susceptibility to develop opportunistic infections. Modified denture base resins can significantly reduce the presence of infection at the point of contact between the denture and the mucous membrane of the prosthetic restoration. Biological tests of modified denture base resins will follow

Antibacterial 3-(arylamino)-1-ferrocenylpropan-1-ones: Synthesis, spectral, electrochemical and structural characterization

Syntheses of fourteen new 3-(arylamino)-1-ferrocenylpropan-1-ones have been achieved in good to excellent yields by an aza-Michael addition of different arylamines to acryloylferrocene. The reaction was performed by microwave (MW) irradiation (500 W/5 min) of a mixture of reactants and montmorillonite K-10, without a solvent. The obtained compounds were spectrally and electrochemically (cyclic voltammetry) fully characterized, whereas single-crystal X-ray analysis has been performed for three of them. In a microdilution assay, all of the compounds were shown to have a broad-spectrum effect on Gram-negative and -positive bacteria, although the degree of inhibition varied. A notable activity was observed for all compounds in inhibiting the growth of an important human pathogen Staphylococcus aureus. (C) 2011 Elsevier B.V. All rights reserved