Browsing by Author "Quelemes, Patrick V."
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- Anthelmintic, Antibacterial and Cytotoxicity Activity of Imidazole Alkaloids fromPilocarpus microphyllusLeavesPublication . Rocha, Jefferson A.; Andrade, Ivanilza M.; Véras, Leiz M.C.; Quelemes, Patrick V.; Lima, David F.; Soares, Maria J.S.; Pinto, Pedro L.S.; Mayo, Simon J.; Ivanova, Galya; Rangel, Maria; Correia, Manuela; Mafud, Ana Carolina; Mascarenhas, Yvonne P.; Delerue-Matos, Cristina; Moraes, Josué de; Eaton, Peter; Leite, José R.S.A.Pilocarpus microphyllus Stapf ex Wardlew (Rutaceae), popularly known as jaborandi, is a plant native to the northern and northeastern macroregions of Brazil. Several alkaloids from this species have been isolated. There are few reports of antibacterial and anthelmintic activities for these compounds. In this work, we report the antibacterial and anthelmintic activity of five alkaloids found in P. microphyllus leaves, namely, pilosine, epiisopilosine, isopilosine, epiisopiloturine and macaubine. Of these, only anthelmintic activity of one of the compounds has been previously reported. Nuclear magnetic resonance, HPLC and mass spectrometry were combined and used to identify and confirm the structure of the five compounds. As regards the anthelmintic activity, the alkaloids were studied using in vitro assays to evaluate survival time and damaged teguments for Schistosoma mansoni adult worms. We found epiisopilosine to have anthelmintic activity at very low concentrations (3.125 μg mL-1 ); at this concentration, it prevented mating, oviposition, reducing motor activity and altered the tegument of these worms. In contrast, none of the alkaloids showed antibacterial activity. Additionally, alkaloids displayed no cytotoxic effect on vero cells. The potent anthelmintic activity of epiisopilosine indicates the potential of this natural compound as an antiparasitic agent. Copyright © 2017 John Wiley & Sons, Ltd.
- Quaternized cashew gum: An anti-staphylococcal and biocompatible cationic polymer for biotechnological applicationsPublication . Quelemes, Patrick V.; Araújo, Alyne R. de; Plácido, Alexandra; Delerue-Matos, Cristina; Maciel, Jeanny S.; Bessa, Lucinda J.; Ombredane, Alicia S.; Joanitti, Graziella A.; Soares, Maria José dos S.; Eaton, Peter; Silva, Durcilene A. da; Leite, José Roberto S.A.Chemical modifications to cashew gum (CG) structure have been previously reported to obtain new physicochemical characteristics, however until now there were no reports of modifications by introduction of new functional groups to add cationic character. This study presents a quaternization route for CG using a quaternary ammonium reagent. The chemical features of the quaternized cashew gum derivatives (QCG) were analyzed by: FTIR, elemental analysis, degree of substitution, Zeta potential, 1H NMR and 1H-13C correlation (HSQC). QCG were evaluated for their anti-staphylococcal activity by determining minimum inhibitory and bactericidal concentrations against pathogenic Staphylococcus spp. and by imaging using atomic force microscopy. Moreover, the mammalian cell biocompatibility were also assessed through hemolytic and cell toxicity assays. QCG presented promising antimicrobial activity against methicillin-resistant S. aureus and biocompatibility on tested cells. These results show that QCG could be a promising tool in the development of biomaterials with an anti-septic action.
- Quaternized cashew gum: An anti-staphylococcal and biocompatible cationic polymer for biotechnological applicationsPublication . Quelemes, Patrick V.; Araújo, Alyne R. de; Plácido, Alexandra; Delerue-Matos, Cristina; Maciel, Jeanny S.; Bessa, Lucinda J.; Ombredane, Alicia S.; Joanitti, Graziella A.; Soares, Maria José dos S.; Eaton, Peter; Silva, Durcilene A. da; Leite, José Roberto S.A.Chemical modifications to cashew gum (CG) structure have been previously reported to obtain new physicochemical characteristics, however until now there were no reports of modifications by intro-duction of new functional groups to add cationic character. This study presents a quaternization route for CG using a quaternary ammonium reagent. The chemical features of the quaternized cashew gum derivatives (QCG) were analyzed by: FTIR, elemental analysis, degree of substitution, Zeta potential, 1H NMR and 1H-13C correlation (HSQC). QCG were evaluated for their anti-staphylococcal activity by deter-mining minimum inhibitory and bactericidal concentrations against pathogenic Staphylococcus spp. and by imaging using atomic force microscopy. Moreover, the mammalian cell biocompatibility were also assessed through hemolytic and cell toxicity assays. QCG presented promising antimicrobial activity against methicillin-resistant S. aureus and biocompatibility on tested cells. These results show that QCG could be a promising tool in the development of biomaterials with an anti-septic action.