Browsing by Author "Mafud, Ana C."
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- HPLC-DAD, ESI-MS/MS, and NMR of Lycopene Isolated From P. guajava L. and Its Biotechnological ApplicationsPublication . Amorim, Adriany G. N.; Souza, Jessica M. T.; Santos, Raimunda C.; Gullón, Beatriz; Oliveira, Ana; Santos, Luiz F. A.; Virgino, Adamor L. E.; Mafud, Ana C.; Petrilli, Helena M.; Mascarenhas, Yvonne P.; Delerue-Matos, Cristina; Pintado, Manuela E.; Leite, José R. S. A.Psidium guajava L. have been reported to be a rich source of antioxidant compounds. Its carotenoids have been highlighted by their high antioxidant capacity, which offers several benefits for human health. In this sense, lycopene isomers need to be identified. In this work, the comprehensive chemical characterization, by HPLC‐DAD, MS/MS, and NMR, of lycopene isolated from P. guajava L., antioxidant and antimicrobial activity of lycopene extracts and isolated lycopene are evaluated. The FTIR results reported a structure with Z configuration, confirmed by UV‐Vis, with λmax = 448, 473, and 505 nm for 5‐Z lycopene. Furthermore, MS/MS positive ionization shows one fragment m/z 309 [M‐227]+, relatively abundant for isolated lycopene. Experimental and Theoretical NMR studies revealed that guava may contain 5‐Z lycopene because of the similarity found among the peaks. Lycopene extracts presented higher antioxidant activity than isolated lycopene, from both P. guajava L. and tomato, when measured by ABTS and ORAC (r2 = 0.9995 and r2 = 0.9992, respectively). In addition, lycopene extract shows antibacterial efficacy against E. coli, S. aureus, and L. innocua, presenting MBC values of 20 mg mL−1. These results suggest that lycopene extract have potential applicability for food, cosmetics, and pharmaceutical industry.Practical Applications: Lycopene from P. guajava L. is characterized by HPLCDAD, MS, NMR, FTIR, and X-Ray, presented antioxidant capacity by ORAC and antibacterial efficacy against food pathogens.
- Layer-by-layer films containing peptides of the Cry1Ab16 toxin from Bacillus thuringiensis for potential biotechnological applicationsPublication . Plácido, Alexandra; Farias, Emanuel Airton de Oliveira; Marani, Mariela M.; Vasconcelos, Andreanne G.; Mafud, Ana C.; Mascarenhas, Yvonne P.; Eiras, Carla; Leite, José R.S.A.; Delerue-Matos, CristinaCry1Ab16 is a toxin of crystalline insecticidal proteins that has been widely used in genetically modified organisms (GMOs) to gain resistance to pests. For the first time, in this study, peptides derived fromthe immunogenic Cry1Ab16 toxin (from Bacillus thuringiensis) were immobilized as layer-by-layer (LbL) films. Given the concern about food and environmental safety, a peptide with immunogenic potential, PcL342–354C, was selected for characterization of the electrochemical, optical, and morphological properties. The results obtained by cyclic voltammetry (CV) showed that the peptide have an irreversible oxidation process in electrolyte of 0.1 mol·L−1 potassiumphosphate buffer (PBS) at pH7.2. Itwas also observed that the electrochemical response of the peptide is governed mainly by charge transfer. In an attempt to maximize the electrochemical signal of peptide, it was intercalated with natural (agar, alginate and chitosan) or synthetic polymers (polyethylenimine (PEI) and poly(sodium 4-styrenesulfonate (PSS)). The presence of synthetic polymers on the film increased the electrochemical signal of PcL342–354C up to 100 times. Images by Atomic Force Microscopy (AFM) showed that the immobilized PcL342–354C formed self-assembled nanofibers with diameters ranging from 100 to 200 nm on the polymeric film. By UV–Visible spectroscopy (UV–Vis) it was observed that the ITO/PE/PSS/PcL342–354C film grows linearly up to the fifth layer, thereafter tending to saturation. X-ray diffraction confirmed the presence on the films of crystalline ITO and amorphous polypeptide phases. In general, the ITO/PEI/PSS/PcL342–354C film characterization proved that this systemis an excellent candidate for applications in electrochemical sensors and other biotechnological applications for GMOs and environmental indicators.