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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.
- Phenolic compounds from Actinidia deliciosa leaves: Caco-2 permeability, enzyme inhibitory activity and cell protein profile studiesPublication . Henriques, Joana; Fale, Pedro; Pacheco, Rita; Florêncio, Maria Helena; Serralheiro, Maria LuisaChemical compounds from leaves of fruit-producing trees, a waste from agricultural activity can be isolated and used as a source of natural bioactive chemicals. Boiling water was used as an extractant of bioactive compounds from Actinidia deliciosa leaves and co-extracted fibres were removed with ethanol precipitation. Rutin and quercitrin were the main flavonoids identified and quantified by RP-HPLC-DAD. No cytotoxicity was detected for any of the extracts towards Caco- 2 cell line. A permeation of approx. 14% of extract components through the cells monolayer was determined. The cell protein profile of Caco-2 cells was modified when in the presence of the fibre-free extract and transketolase was the protein over-expressed in the presence of polyphenols. Acetylcholinesterase inhibitory activity was also studied, IC50 of 0.56 mg/mL was obtained with the fibre-free extract. A. deliciosa leaves are a good source of phenolic compounds and, therefore, some advantage may be taken of this agricultural residue, due to their biological activity.
- Action of euptox A from Ageratina adenophora juice on human cell lines: a top-down study using FTIR spectroscopy and protein profilingPublication . André, Rebeca; Catarro, Joana; Freitas, Dalia; Pacheco, Rita; Oliveira, Maria Conceição; Serralheiro, Maria Luisa; Fale, PedroEuptox A, from Ageratina adenophora juice, is a toxin associated with the plant's resistance to infections, invasiveness and traditional use in cancer treatment. We used FTIR spectroscopy and protein profiling of cell lines to study the impact of euptox A on human cells, to clarify its mechanism of action in a top-down approach. Euptox A was extracted from the juice of A. adenophora. Its stability in the gastrointestinal tract was evaluated, as the compound/juice is generally taken orally. Cytotoxicity was determined in HeLa, Caco-2 and MCF7 cells, and the mechanism of action analyzed by protein and metabolite profiles using electrophoresis and FTIR spectroscopy. Euptox A resisted gastrointestinal digestion and was the most cytotoxic component of the extract for all cell lines tests. Euptox A-treated HeLa cells showed changes in protein profile, especially on 40S ribosomal protein S8 (RP), generally associated with cancer cells. FTIR profiles of treated cells diverged in the same metabolites as cells treated with cisplatin, both in metabolite directed analysis and in multivariate analysis (principal component analysis). In conclusion, euptox A in this top-down study showed a cellular impact that suggests a strong potential against cancer, acting on cancer targeted cellular characteristics.
- Biological properties of phenolic compound extracts in selected Algerian honeys-The inhibition of acetylcholinesterase and alpha-glucosidase activitiesPublication . Zaidi, Hicham; Ouchemoukh, Salim; Amessis-Ouchemoukh, Nadia; DEBBACHE-BENAIDA, NADJET; Pacheco, Rita; Serralheiro, Maria Luisa; Araujo, Maria EduardaIntroduction: Honey is used in various cultures as a traditional medicine and folkloric treatment. The aim of this study was to determine the antioxidant and the anti-inflammatory activities of 31 Algerian honeys and acetylcholinesterase (AChE) and alpha-glucosidase inhibitory activities of phenolic compounds extracts of these honeys. Methods: The anti-inflammatory activity of honey was evaluated by the method of inhibition of BSA (Bovin Serum Albumin) heat-induced denaturation. The inhibition of AChE and alpha-glucosidase by the honey extracts was evaluated by in-vitro methods. Results: The highest percentage of inhibition (85.33%) of BSA denaturation was obtained with polyfloral honey (H27). Radical scavenging activity of honey samples against 1,1-diphenyl-2-picrilhydrazyl (DPPH), and 2,2'-azinobis(-3) -ethylbenzothiazoline-6-sulfonic acid (ABTS) varied from 4.41 to 83.93% and from 2.52 to 63.24%, respectively. AChE inhibitory activity is one target to prevent neurodegenerative damage in Alzheimer's disease. AChE inhibition recorded values from 20.69 to 76.04%. alpha-glucosidase inhibitors such as acarbose is preconized for the control of hyperglycemia and prevent diabetes damages. Honey extracts demonstrated a significant inhibitory effect on alpha-glucosidase activity. Moreover, the effect of Fabacece honey (H19) (IC50 = 52.20 mu g/mL) was found to be more potent than acarbose (IC50 = 204.27 mu g/mL). Correlations were observed between antioxidants and anti-inflammatory activities, AChE and alpha-glucosidase inhibitions with total phenolic compounds and flavonoids content in honey samples. Conclusion: This study showed that honey could be exploited as a potential antioxidant and anti-inflammatory agent within therapeutic medicine.
- Cork processing wastewaters components fractioned by ultrafiltration membranes–studies of antioxidant and antitumoral activityPublication . Gomes, Luís; Borges, Carlos; Serralheiro, Maria Luisa; Minhalma, Miguel; Pacheco, RitaBACKGROUND: Cork processing wastewater is an environmental problem due to its high content of organic matter, such as sugars and non-biodegradable compounds such as polyphenols (PPs), namely tannins. Membrane technology aimed at valorisation of the wastewaters components, concentrate stream, and simultaneously offer a pre-treatment of the wastewater, permeate stream. In this work, the identification of bioactive PPs was also envisaged. Several fractions of cork processing wastewaters were generated using two cellulose acetate ultrafiltration membranes of 3 kDa and 74 kDa for PPs isolation according to nature and molecular weights. The membranes were prepared by the phase inversion method and fractionation was made in concentration and diafiltration modes. The wastewater and the fractions were analyzed in terms of total organic carbon, total phenols, tannins and total polysaccharides content and the compounds present were identified by FTIR, LC–MS and quantified by HPLC-DAD. RESULTS: Compounds such as quinic, gallic, protocatechuic, brevifolin carboxylic and ellagic acids were identified as the major compounds in cork wastewater. The wastewater and the fractions were tested for antioxidant activity and for capacity to inhibit the proliferation of the growth of human breast carcinoma cell lines, MCF-7. The fractions revealed high antioxidant activity with EC 50 values ranging from 1.174 ± 0.069 to 1.943 ± 0.179 mg/mgDPPH. The fractions demonstrated to be efficient as cell proliferation inhibitors, with values of IC50 ranging from 0.20 ± 0.003 to 0.46 ± 0.02 mg mL-1. CONCLUSION: The process reported demonstrates that PPs compounds can be recovered from cork effluent and further reused as high-value bioactive compounds.
- Antiacetylcholinesterase activity and docking studies with chlorogenic acid, cynarin and arzanol from Helichrysum stoechas (Lamiaceae)Publication . Silva, Leticia; Rodrigues, Ana M.; Ciriani, Marina; Fale, Pedro Luís Vieira; Teixeira, Vítor; Madeira, Paulo; Machuqueiro, Miguel; Pacheco, Rita; Florêncio, Maria Helena; Ascensão, Lia; Serralheiro, Maria LuisaThis work was aimed at the study of the chemical composition in phenolic compounds responsible for the high antiacetylcholinesterase activity of aqueous extracts (decoctions) from Helichrysum stoechas aerial parts. Chlorogenic acid, cynarin, and arzanol were the main components of decoctions, detected by high-performance liquid chromatography with diode-array detection and liquid chromatography-mass spectrometry/mass spectrometry. Flowers and stems/leaves extracts inhibited antiacetylcholinesterase with IC50 values of 260.7 and 654.8 mu g/mL, respectively. The biological activity of these extracts was maintained after in vitro gastrointestinal digestion, indicating that the active compounds present in the extracts were not enzymatically modified by the gastrointestinal system used to simulate the digestion. Molecular docking studies with the main components were carried out in order to obtain information, at the molecular level, as to how these compounds access the enzyme's active site. The docking study showed for the first time that chlorogenic acid, cynarin, and arzanol fit nicely in the antiacetylcholinesterase active site channel, blocking all access to the catalytic triad. This explained the high inhibitory activity determined during in vitro experiments.
- 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.
- Antiacetylcholinesterase activity and docking studies with chlorogenic acid, cynarin and arzanol from Helichrysum stoechas (Asteraceae)Publication . Silva, Letícia; Rodrigues, Ana M.; Ciriani, Marina; Falé, Pedro Luís Vieira; Teixeira, Vitor; Madeira, Paulo; Machuqueiro, Miguel; Pacheco, Rita; Florêncio, Maria Helena; Ascensão, Lia; Serralheiro, Maria LuisaThis work was aimed at the study of the chemical composition in phenolic compounds responsible for the high antiacetylcholinesterase activity of aqueous extracts (decoctions) from Helichrysum stoechas aerial parts. Chlorogenic acid, cynarin, and arzanol were the main components of decoctions, detected by high-performance liquid chromatography with diode-array detection and liquid chromatography-mass spectrometry/mass spectrometry. Flowers and stems/leaves extracts inhibited antiacetylcholinesterase with IC50 values of 260.7 and 654.8 μg/mL, respectively. The biological activity of these extracts was maintained after in vitro gastrointestinal digestion, indicating that the active compounds present in the extracts were not enzymatically modified by the gastrointestinal system used to simulate the digestion. Molecular docking studies with the main components were carried out in order to obtain information, at the molecular level, as to how these compounds access the enzyme’s active site. The docking study showed for the first time that chlorogenic acid, cynarin, and arzanol fit nicely in the antiacetylcholinesterase active site channel, blocking all access to the catalytic triad. This explained the high inhibitory activity determined during in vitro experiments.
- Valorization of kiwifruit production: leaves of the pruning branches of Actinidia deliciosa as a promising source of polyphenolsPublication . Henriques, Joana; Ribeiro, Maria João; Fale, Pedro L; Pacheco, Rita; Ascenso, Lia; Florêncio, Maria Helena; Serralheiro, Maria LuisaThe present work concerns the novel application of a phenolic compound extraction methodology to leaves of Actinidea deliciosa. Recent studies have shown that crop residues could be raw material for recovery of natural bioactive compounds. Phenolic compounds from Actinidea deliciosa leaves were extracted with hot water, purified using reverse phase chromatography and mucilage precipitation with ethanol. The composition of the purified fraction was determined by HPLC-DAD and LC-MSn. Quercitrin, rutin, proantocyanidin B and C, quinic acid, myricitrin, and triterpene acid-O-hexoside were found. These compounds were present in all the fractions. The antioxidant activity was determined as general radical scavenging capacity, lipid peroxidation prevention, and NO radical scavenging activity. Values of EC50 of 9.4 mu g/mL, IC50 of 152.5 mu g/mL, and IC50 of 81 mu g/mL were determined, respectively. The best period of the year to obtain a high fraction of phenolic compounds (120 A mu g/mg of extract) from A. deliciosa leaves was December. The phenolic fraction obtained with hot water and ethanol precipitation is a promising good source of natural bioactive compounds and an easy method of taking advantage of the leaves from A. deliciosa. To the best of our knowledge, there are no previous works on the use of the residual leaves of this fruit tree. Several phenolic compounds with high antioxidant activity were extracted and identified in this plant for the first time.
- Serum albumin modulates the bioactivity of rosmarinic acidPublication . Brito, Elsa; Silva, André; Fale, Pedro; Pacheco, Rita; Serralheiro, António; Haris, Parvez I.; Ascensão, Lia; Serralheiro, Maria LuisaRosmarinic acid (RA) is a phenolic compound with biological activity. The objective of the present study was to investigate whether this compound kept its biological activity in the presence of proteins. For this purpose, bovine serum albumin (BSA) was used as a model protein, and the capacity of the RA to inhibit acetylcholinesterase (AChE) and affect antioxidant activity was evaluated in the absence and presence of BSA. A mixture of phenolic compounds containing RA, obtained from a medicinal plant was added to this study. The AChE inhibitory activity of RA was reduced by *57% in the presence of BSA, while the antioxidant activity increased. These results lead to the investigation of the effect of RA on the BSA structure using Fourier transform infrared spectroscopy (FTIR). At 37 C and higher temperatures, RA caused a decrease in the temperature modifications onthe proteinstructure. Furthermore, FTIR and native-gel analysis revealed that protein aggregation/ precipitation, induced bytemperature, wasreduced in thepresence of RA. The novelty of the present work resides in thestudy of the enzyme inhibitory activity and antioxidant capacity of polyphenols, such as RA, in the presence of a protein. The findings highlight the need to consider the presence of proteins when assessing biological activities of polyphenols in vitro and that enzyme inhibitory activity may be decreased, while the antioxidant capacity remains or even increases.