Browsing by Author "Philippsen, Gisele Strieder"
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- Effect of Curcuma longa L. extract and curcumin on porcine pancreatic α-amylase structure and activityPublication . Oliveira, Grazielle; Kaspchak, Elaine; Oliveira, Anielle; Leimann, Fernanda Vitória; Philippsen, Gisele Strieder; Seixas, Flávio Augusto Vicente; Igarashi-Mafra, Luciana; Mafra, Marcos R.This work aimed to evaluate alpha-amylase activity and structure in the presence of Curcuma longa L. extracts obtained with deep eutectic solvent (DES) and curcumin. Isothermal titration calorimetry (ITC), fluorescence, circular dichroism (CD), and molecular docking were applied to study the effect of additives on enzyme activity and structure. Results showed that in the presence of turmeric extracts, there was a lower catalytic rate. Through the ITC analysis, a lower reaction rate was noticed, related to the inhibition of the enzymatic activity, both in the presence of the extract and of curcumin. The turmeric extracts interacted with the enzyme by a static mechanism as demonstrated by fluorescence. CD showed an increase in negative bands characteristic of hydrophobic interactions between the enzyme and the samples, which probably difficult the access of substrate to the enzyme's active site. Molecular docking showed that curcumin is capable to interact with the active site of alpha-amylase confirming results obtained by other techniques. Results presented in this work show the turmeric extracts potential for alpha-amylase inhibition which may be of interest to the pharmaceutical and food industry.
- Potential of plant extracts in targeting SARS-CoV-2 main protease: an in vitro and in silico studyPublication . Araujo, Ingrid Garcia de; Pattaro-Junior, Jose Renato; Barbosa, Cecilia Gomes; Philippsen, Gisele Strieder; Silva, Ana Rita; Ioshino, Rafaella Sayuri; Moraes, Carolina Borsoi; Freitas-Junior, Lucio Holanda; Barros, Lillian; Peralta, Rosane M.; Fernandez, Maria Aparecida; Seixas, Flávio Augusto VicenteThe deaths caused by the covid-19 pandemic have recently decreased due to a worldwide effort in vaccination campaigns. However, even vaccinated people can develop a severe form of the disease that requires ICU admission. As a result, the search for antiviral drugs to treat these severe cases has become a necessity. In this context, natural products are an interesting alternative to synthetic medicines used in drug repositioning, as they have been consumed for a long time through traditional medicine. Many natural compounds found in plant extracts have already been shown to be effective in treating viral and bacterial diseases, making them possible hits to exploit against covid-19. The objective of this work was to evaluate the antiviral activity of different plant extracts available in the library of natural products of the Universidade Estadual de Maringa, by inhibiting the SARS-CoV-2 main protease (M-pro), and by preventing viral infection in a cellular model. As a result, the extract of Cytinus hypocistis, obtained by ultrasound, showed a M-pro inhibition capacity greater than 90%. In the infection model assays using Vero cells, an inhibition of 99.6% was observed, with a selectivity index of 42.7. The in silico molecular docking simulations using the extract compounds against M-pro, suggested Tellimagrandin II as the component of C. hypocistis extract most likely to inhibit the viral enzyme. These results demonstrate the potential of C. hypocistis extract as a promising source of natural compounds with antiviral activity against covid-19.