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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.
- Molecular-level changes induced by hydroxycinnamic acid derivatives in HepG2 cell line: comparison with pravastatinPublication . RESSAISSI, Asma; Pacheco, Rita; Serralheiro, Maria LuisaHydroxycinnamic acid derivatives are an important class of polyphenols found in fruits, vegetables, and medicinal plants and widely consumed in human diet. In the present work, alterations of HepG2 cells biochemical profile under the effect of four hydroxycinnamic acid derivatives (caffeic acid, m-coumaric acid, chlorogenic acid and rosmarinic acid) relatively to the effect of pravastatin, a drug often prescribed to inhibit HMG-CoA reductase enzyme, the regulator enzyme in the cholesterol biosynthesis pathway, were reported. The application of FTIR spectroscopy in combination with multivariate analysis by PCA showed a similarity between pravastatin and the four hydroxycinnamic acid derivatives in metabolite profile modification expressed by various changes in proteins region, the phosphate region which mainly corresponds to nucleic acids as well as in lipids regions. FTIR structural analysis in the amide I region, using resolution enhancement methods, such as second derivative and amide I deconvolution method, revealed significant decrease in alpha-helix/random coil and intermolecular beta-sheet decreased while intramolecular beta-sheet in treated cells showed an increase. It was also noticed that the intracellular cholesterol as well as esterified ingredients such as cholesterol esters in the cell membrane decreased. Moreover, principal component analysis (PCA) of the spectral data showed that the compounds and pravastatin were well separated from untreated cells showing a different mode of action on HepG2 treated cells for each compound.
- Cholesterol transporter proteins in HepG2 cells can be modulated by phenolic compounds present in Opuntia ficus-indica aqueous solutionsPublication . RESSAISSI, Asma; ATTIA, Nebil; Pacheco, Rita; Fale, Pedro; Serralheiro, Maria LuisaIncreased blood cholesterol is a risk factor for atherosclerotic cardiovascular disease. This study tested the hypothesis that phenolic compounds can modulate the level of cholesterol transporters including Niemann-Pick C1-like 1 (NPC1L1) and ATP-binding cassette transporters in liver cells. HepG2 cells, used as a model of hepatocytes, showed a decrease in the abundance of cholesterol transporters comparatively to the control when treated with the Opuntia ficus-indica's cladodes decoction. The decrease was between 13-70%, 25-60%, 9-60% and 23-60% for NPC1L1, ABCA1, ABCG5 and ABCG8 transporters, respectively, when using between 0.15 and 0.35 mg/mL of decoction in the culture medium. FTIR analysis showed changes in the amount of RNA, which may be the cause of the decrease in the level of several proteins. These in vitro results pave the way to a molecular explanation for the decoction of cladodes effect on cholesterol levels as it reduced the membrane cholesterol transporter proteins, NPC1L1, ABCG5/ABCG8 and ABCA1, in HepG2 cells.
- 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.