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- BioMol4Health_Biological chemistry: longevity in a cup of teaPublication . RESSAISSI, Asma; Fale, Pedro; Pacheco, Rita; Serralheiro, Maria LuisaInfusions have been studied on what concerns Alzheimer Disease, digestive process, diet cholesterol absorption and its biosynthesis inhibition. In the first two cases the inhibition of acetylcholinesterase (AChE) has been addressed. In the last two situations, an in vitro intestinal barrier has been simulated and the inhibition of the regulator enzyme (HMGR) in cholesterol biosysnthesis pathway has been studied. AChE has been the target of infusions inhibitory activity as its inhibition has been seen to improve cognition and global functioning1 in AD suffering people and to improve the gastrointestinal motility2. Given to lab animals the compounds presente in the infusions were able to reach the brain and inhibit the enzyme3. The effect of infusions on cholesterol bioavailability pointed out that some infusions were able to reduce cholesterol permeation4 and also to have some inhibitory activity5. Studies have indicated that phenolics are able to modify the cell proteome6. The infusions have also been shown to modify the amount of cholesterol transporter proteins in cell membrane and this maybe one of possible explanations for the reduction in cholesterol transport detected under the effect of infusions, on some people ando n simulated intestinal barrier.
- Isorhamnetin derivatives and piscidic acid for hypercholesterolemia: cholesterol permeability, HMG-CoA reductase inhibition, and docking studiesPublication . RESSAISSI, Asma; ATTIA, Nebil; Falé, Pedro Luís; Pacheco, Rita; Victor, Bruno L.; Machuqueiro, Miguel; Serralheiro, Maria Luísa M.Bioactive compounds, such as isorhamnetin and piscidic acid, were obtained from decoctions of cladodes (stem pads from Opuntia ficus-indica). The effect of these phenolic compounds, in a fiber-free extract, were evaluated as inhibitors of cholesterol permeation through a Caco-2 cell monolayer and as 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. A reduction of 38% in cholesterol permeation through the Caco-2 cell monolayer was obtained, and the phenolic compounds all permeated between 6 and 9%. A mixture of these compounds showed an IC50 of 20.3 mu g/mL as an enzyme inhibitor, whereas piscidic acid alone showed an IC50 of 149.6 mu g/mL; this was slightly outperformed by the isorhamnetin derivatives. Docking studies confirmed that both piscidic acid and isorhamnetin derivatives, present in the decoction, could adequately bind to the enzyme active site. These results reveal that O. ficus-indica, and cladodes derived there from, is a promising plant for use in the development of new functional foods and pharmaceutical products.
- 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.