Browsing by Author "Petrovski, Zeljko"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Antimicrobial activities of highly bioavailable organic salts and ionic liquids from fluoroquinolonesPublication . Santos, Miguel M.; Alves, Celso; Silva, Joana; Florindo, Catarina; Petrovski, Zeljko; Marrucho, Isabel M.; Pedrosa, Rui; Branco, Luís C.As the development of novel antibiotics has been at a halt for several decades, chemically enhancing existing drugs is a very promising approach to drug development. Herein, we report the preparation of twelve organic salts and ionic liquids (OSILs) from ciprofloxacin and norfloxacin as anions with enhanced antimicrobial activity. Each one of the fluoroquinolones (FQs) was combined with six di erent organic hydroxide cations in 93–100% yield through a bu er-assisted neutralization methodology. Six of those were isomorphous salts while the remaining six were ionic liquids, with four of them being room temperature ionic liquids. The prepared compounds were not toxic to healthy cell lines and displayed between 47- and 1416-fold more solubility in water at 25 and 37 C than the original drugs, with the exception of the ones containing the cetylpyridinium cation. In general, the antimicrobial activity against Klebsiella pneumoniae was particularly enhanced for the ciprofloxacin-based OSILs, with up to ca. 20-fold decreases of the inhibitory concentrations in relation to the parent drug, while activity against Staphylococcus aureus and the commensal Bacillus subtilis strain was often reduced. Depending on the cation–drug combination, broad-spectrum or strain-specific antibiotic salts were achieved, potentially leading to the future development of highly bioavailable and safe antimicrobial ionic formulations.
- Highlighting the biological potential of the brown seaweed Fucus spiralis for skin applicationsPublication . Freitas, Rafaela; Martins, Alice; Silva, Joana; Alves, Celso; Pinteus, Susete; Alves, Joana; Teodoro, Fernando; Ribeiro, Helena Margarida; Gonçalves, Lídia; Petrovski, Zeljko; Branco, Luís; Pedrosa, RuiSkin aging is a biological process influenced by intrinsic and extrinsic factors. The last ones, mainly exposure to UV radiation, increases reactive oxygen species (ROS) production leading to a loss of extracellular matrix, also enhanced by enzymatic degradation of matrix supporting molecules. Thus, and with the growing demand for eco-friendly skin products, natural compounds extracted from brown seaweeds revealed to be good candidates due to their broad range of bioactivities, especially as antioxidants. The aim of this study was to assess the dermo-cosmetic potential of di erent fractions obtained from the brown seaweed Fucus spiralis. For this purpose, in vitro antioxidant (Total Phenolic Content (TPC), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, Ferric Reducing Antioxidant Power (FRAP), Oxygen Radical Absorbance Capacity (ORAC)), anti-enzymatic (collagenase, elastase and hyaluronidase), antimicrobial, anti-inflammatory (NO production) and photoprotective (ROS production) capacities were evaluated. Although nearly all fractions evidenced antioxidant e ects, fraction F10 demonstrated the highest antioxidant ability (EC50 of 38.5 g/mL, DPPH assay), and exhibited a strong e ect as an inhibitor of collagenase (0.037 g/mL) and elastase (3.0 g/mL). Moreover, this fraction was also the most potent on reducing ROS production promoted by H2O2 (IC50 of 41.3 g/mL) and by UVB (IC50 of 31.3 g/mL). These bioactivities can be attributed to its high content of phlorotannins, as evaluated by LC-MS analysis, reinforcing the potential of F. spiralis for further dermatological applications.
- Unravelling the dermatological potential of the brown seaweed Carpomitra costataPublication . Susano, Patrícia; Silva, Joana; Alves, Celso; Martins, Alice; Gaspar, Helena; Pinteus, Susete; Mouga, Teresa; Goettert, Márcia Ines; Petrovski, Zeljko; Branco, Luís B.; Pedrosa, RuiThe ever-increasing interest in keeping a young appearance and healthy skin has leveraged the skincare industry. This, coupled together with the increased concern regarding the safety of synthetic products, has boosted the demand for new and safer natural ingredients. Accordingly, the aim of this study was to evaluate the dermatological potential of the brown seaweed Carpomitra costata. The antioxidant, anti-enzymatic, antimicrobial, photoprotective and anti-inflammatory properties of five C. costata fractions (F1–F5) were evaluated. The ethyl acetate fraction (F3) demonstrated the most promising results, with the best ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (EC50 of 140.1 g/mL) and the capacity to reduce reactive oxygen species (ROS) production promoted by UVA and UVB radiation in 3T3 cells, revealing its antioxidant and photoprotective potential. This fraction also exhibited the highest anti-enzymatic capacity, inhibiting the activities of collagenase, elastase and tyrosinase (IC50 of 7.2, 4.8 and 85.9 g/mL, respectively). Moreover, F3 showed anti-inflammatory potential, reducing TNF- and IL-6 release induced by LPS treatment in RAW 264.7 cells. These bioactivities may be related to the presence of phenolic compounds, such as phlorotannins, as demonstrated by NMR analysis. The results highlight the potential of C. costata as a source of bioactive ingredients for further dermatological applications.