Browsing by Author "Guedes, Laura"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Bioactivities of centaurium erythraea (Gentianaceae) decoctions: antioxidant activity, enzyme inhibition and docking studiesPublication . Guedes, Laura; Reis, Pedro B. P. S.; Machuqueiro, Miguel; RESSAISSI, Asma; Pacheco, Rita; Serralheiro, Maria LuisaCentaurium erythraea is recommended for the treatment of gastrointestinal disorders and to reduce hypercholesterolemia in ethno-medicinal practice. To perform a top-down study that could give some insight into the molecular basis of these bioactivities, decoctions from C. erythraea leaves were prepared and the compounds were identified by liquid chromatography-high resolution tandemmassspectrometry(LC–MS/MS).Secoiridoidsglycosides,likegentiopicrosideandsweroside, and several xanthones, such as di-hydroxy-dimethoxyxanthone, were identified. Following some of the bioactivities previously ascribed to C. erythraea, we have studied its antioxidant capacity and the ability to inhibit acetylcholinesterase (AChE) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Significant antioxidant activities were observed, following three assays: free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction; lipoperoxidation; and NO radical scavengingcapacity. TheAChEandHMGRinhibitoryactivitiesforthedecoctionwerealsomeasured (56% at 500 µg/mL and 48% at 10 µg/mL, respectively). Molecular docking studies indicated that xanthones are better AChE inhibitors than gentiopicroside, while this compound exhibits a better shape complementarity with the HMGR active site than xanthones. To the extent of our knowledge, thisisthefirstreportonAChEandHMGRactivitiesbyC.erythraeadecoctions,inatop-downanalysis, complemented with in silico molecular docking, which aims to understand, at the molecular level, some of the biological effects ascribed to infusions from this plant.
- Bioactivities of iridoids and flavonoids present in decoctions from aerial parts of Verbascum betonicifoliumPublication . Fadel, Sezan R.; Bendif, Hamdi; Guedes, Laura; André, Rebeca; Pacheco, Rita; Guedes, Rita; Merabti, Karim; Miara, Mohamed Djamel; Serralheiro, Maria LuisaIntroduction: Verbascum betonicifolium (V. betonicifolium) is a plant used in traditional medicine for several ailments. The objective of this study was to determine the antioxidant activity and acetylcholinesterase inhibitory activity of the aqueous extract together with the metabolites responsible for these activities. This paper presents the first phytochemical characterization and bioactivities of aqueous extracts from aerial parts. Methods: The compounds present in the aerial part aqueous extract were identified by high performance liquid chromatography, coupled to a diode-array detector (HPLC-DAD) and by high-resolution mass spectrometry (HRMS), using LC-MS/MS analyses. Antioxidant activity was measured as the capacity to scavenge the free radical DPPH and the AChE activity was determined using the Ellman test. The cytotoxicity was determined used HepG2 cell lines. Results: Several types of metabolites were found, primary metabolites (malic, citric and gluconic acids), phenolic compounds (verbascoside, luteolin), terpenoids (iridoid glycoside, unedide), among others. The total phenol content of 28 mu g of gallic acid equivalents/mg of extract was determined. The aqueous extract antioxidant activity had and EC50 of 70 mu g/mL and the AChE inhibitory activity an IC50 of 750 mu g/mL. No cytotoxicity towards HepG2 cells was detected, even using a concentration of 1 mg/mL. Conclusions: The phenolic compounds present in the extract may be the main contributors to the bioactivities of V. betonicifolium. These results show for the first time the richness of phytochemicals and the strong bioactivities of V. betonicifolium and that the aqueous extract could be used as new natural sources of bioactive molecules.
- Effect of food preparations on in vitro bioactivities and chemical components of fucus vesiculosusPublication . André, Rebeca; Guedes, Laura; Melo, Ricardo; Ascensão, Lia; Pacheco, Rita; Vaz, Pedro D.; Serralheiro, Maria LuisaFucus vesiculosus is a brown macroalgae used in food and generally considered safe to be consumed, according to EU Directive (EC 258/97). The aim of this study is to analyze the e_ect of food preparation on F.vesiculosus of di_erent origins on what concerns its chemical constituents and final bioactivities. The aqueous extract of the seaweeds were obtained at di_erent temperatures, similar to food preparation and then purified by SPE. The compound identification was carried out by Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS/MS) and algae extracts microstructure were observed by Scanning Electron Microscopy (SEM). The activities were determined by using antioxidant activity, inhibition of acetylcholinesterase (AChE) and 3-hidroxi-3-methyl-glutaril-CoA (HMG-CoA) reductase (HMGR) together with Caco-2 cells line simulating the intestinal barrier. The activity of AChE and the HMGR were inhibited by the extracts giving IC50 values of 15.0 _ 0.1 _g/mL and 4.2 _ 0.1 _g/mL, respectively and 45% of the cholesterol permeation inhibition. The main compounds identified were phlorotannins and peptides derivatives. The mode of preparation significantly influenced the final bioactivities. Moreover, the in vitro results suggest that the preparation of F. vesiculosus as a soup could have hypercholesterolemia lowering effect.