| 1. |
- Bustos, Atma-Sol, et al.
(författare)
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Interaction between Myricetin Aggregates and Lipase under Simplified Intestinal Conditions
- 2020
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- Myricetin, a flavonoid found in the plant kingdom, has previously been identified as a food molecule with beneficial effects against obesity. This property has been related with its potential to inhibit lipase, the enzyme responsible for fat digestion. In this study, we investigate the interaction between myricetin and lipase under simplified intestinal conditions from a colloidal point of view. The results show that myricetin form aggregates in aqueous medium and under simplified intestinal condition, where it was found that lipase is in its monomeric form. Although lipase inhibition by myricetin at a molecular level has been reported previously, the results of this study suggest that myricetin aggregates inhibit lipase by a sequestering mechanism as well. The size of these aggregates was determined to be in the range of a few nm to >200 nm.
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| 2. |
- Bustos, Atma Sol, et al.
(författare)
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Interaction Between Phenolic Compounds and Lipase : The Influence of Solubility and Presence of Particles in the IC50 Value
- 2018
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 83:8, s. 2071-2076
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is one of the principal human health problems and one of the main treatments against it is the inhibition of pancreatic lipase, the main responsible enzyme of lipid digestion. For that purpose, previous studies have tested several phenolic compounds against lipase, without considering their aggregation behavior in aqueous solutions. Because of this, the present study focuses on understanding how the solubility and the presence of particles affect the IC50 value of the interaction between lipase and phenolic compounds present in beverages like fruit juices and teas. Therefore, the inhibitory capacity against pancreatic lipase and the aggregate formation of 9 phenolic compounds (quercetin, rutin, myricetin, catechin, epigallocatechin gallate, cyanidin, caffeic acid, chlorogenic acid, and vanillic acid) were analyzed. The results obtained together with the solubility data from literature were treated by principal component analysis and indicate that the IC50 value does not correlate with the solubility or aggregate formation of the phenolic compounds. However, the IC50 values of phenolic compounds which aggregate during the assay conditions have low reproducibility. This study shows that the aggregate formation of phenolic compounds plays an important role during in vitro assays for pancreatic lipase inhibition and should be considered in future experiments as it can lead to false positive results. In terms of particle formation, the flavonoids investigated in this study are more prone to aggregation compared to the phenolic acids.
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| 3. |
- Bustos, Atma-Sol, et al.
(författare)
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Interaction of quercetin and epigallocatechin gallate (EGCG) aggregates with pancreatic lipase under simplified intestinal conditions
- 2020
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:4, s. 0224853-0224853
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Tidskriftsartikel (refereegranskat)abstract
- Diets rich in flavonoids have been related with low obesity rates, which could be related with their potential to inhibit pancreatic lipase, the main enzyme of fat assimilation. Some flavonoids can aggregate in aqueous medium suggesting that the inhibition mechanism could occur on both molecular and colloidal levels. This study investigates the interaction of two flavonoid aggregates, quercetin and epigallocatechin gallate (EGCG), with pancreatic lipase under simplified intestinal conditions. The stability and the morphology of these flavonoid aggregates were studied in four different solutions: Control (water), salt, low lipase concentration and high lipase concentration. Particles were found by optical microscopy in almost all the solutions tested, except EGCG-control. The results show that the precipitation rate decreases for quercetin and increases for EGCG in salt solution and that lipase stabilize quercetin aggregates. In addition, both flavonoids were shown to precipitate together with pancreatic lipase resulting in a sequestering of the enzyme.
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| 4. |
- Bustos, Atma-Sol
(författare)
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Lipases and phenolic aggregates : Characterization, inhibition and interaction
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent decades, obesity has gone from being a problem of first world countries to a global one. It is considered one of the main risk factors for many serious medical conditions. In order to treat and/or prevent obesity different strategies have been considered, one of the most common being the inhibition of lipase, the enzyme that is mainly responsible for lipid digestion. Even though there is a commercial drug that can inhibit lipase (orlistat), the most accessible treatment for obesity is based on the intake of a healthy diet. For example, some studies show that a diet rich in phenolic compounds is related to a low obesity index and that this can be related to their potential to inhibit lipase. The obesity studies based on lipase inhibition make use of endogenous lipases, such as gastric and pancreatic lipase, but there have been no studies of exogenous lipases, such as from probiotics, even though there are studies that reveal that probiotics could have an effect on obesity. Thus, in the present thesis, two potential lipases from Biffidobacterium longum NCC 2705 and Lactobacillus rhamnosus GG were investigated. Both were produced and characterized. The results indicate that both are active under physiological conditions in their monomeric forms. Also, they were able to hydrolyze long‐chain acyl groups (>C10), hence they present lipase activity. The inhibition of lipase by phenolic compounds has been widely investigated. The results indicate that the inhibition takes place at molecular levels when the phenolic compounds are considered soluble. From the literature it is known that some phenolic compounds have low solubility in aqueous systems and they can form aggregates in solution. Thus, understanding the role that these phenolic aggregates play in lipase inhibition could help to comprehend their relevance in lipid digestion. For the aforementioned, the interaction between pancreatic lipase and phenolic aggregates was also investigated in the present thesis. The results suggest that, among the studied phenolic compounds, flavonoids are more prone to form aggregates in aqueous medium and that the presence of these aggregates in a solution could affect the reproducibility of lipase assays. Three flavonoids were chosen in order to study in detail their interaction with lipase (myricetin, quercetin and EGCG). All of them were able to form aggregates in water and in the presence of lipase under simulated intestinal conditions. These aggregates have shown to interact with lipase by a sequestering mechanism under the intestinal conditions that were tested, in which it was found that lipase was in its monomeric form. The results of this thesis suggest that lipase inhibition by phenolic compounds can occur both by molecular mechanism, such as non‐competitive inhibition, and by a sequestering mechanism when phenolic aggregates are formed. The phenolic concentrations used in this thesis are common values found in drinkable products, therefore, the results from this thesis suggest that the inhibition by aggregates take place in real conditions.
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| 5. |
- Ibieta, Gabriela, et al.
(författare)
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Molecular characterization of a galactomannan extracted from Tara (Caesalpinia spinosa) seeds
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Tara gum (TG) is a polysaccharide extracted from the seeds of a South American tree called Tara (Caesalpinia spinosa). TG is a galactomannan with many applications in the food industry, mainly as an emulsifier and stabilizer agent. In addition, it is also used in the paper and cosmetic industries. In the present study, we performed a molecular characterization based on chemical composition and physicochemical properties to understand the properties behind TG applications. TG was extracted and purified from Tara seeds distributed in different ecoregions of Bolivia. The monosaccharide composition analysis was determined by high-performance anion-exchange chromatography/pulsed amperometric detection (HPAEC-PAD). At the same time, their molecular characteristics, such as molar mass, root-mean-square radius, hydrodynamic radius, conformation, and densities, were studied by asymmetrical flow field-flow fractionation coupled to multi-angle light scattering refractive index (AF4-MALS-dRI), also the specific refractive index increment (dn/dc) was determined for the first time using AF4 for TG. The results revealed that the gum samples are galactomannans composed of mannose (Man) and galactose (Gal) in a ratio of 3.37 (Man/Gal), with an average molar mass range from 2.460 × 107 to 3.699 × 107 Da, distributed in a single population. The root-mean-square radius range from 260.4 to 281.6 nm, and dn/dc is 0.1454. The Kratky plots based on 14 scattering angles indicated that the conformation of all samples corresponds to random coil monodisperse, while their gyration radius/hydrodynamic radius ratio (ρ) is high. All these results suggest that the chains have a low branched density, consistent with the Gal/Man composition. To the best of our knowledge, we report for the first time an integrated physicochemical study of TG relevant to developing emulsifier and stabilizer formulations.
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| 6. |
- Manasian, Panagiotis, et al.
(författare)
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First Evidence of Acyl-Hydrolase/Lipase Activity From Human Probiotic Bacteria: Lactobacillus rhamnosus GG and Bifidobacterium longum NCC 2705
- 2020
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X.
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Tidskriftsartikel (refereegranskat)abstract
- Lactobacillus rhamnosus GG (ATCC 53103) and Bifidobacterium longum NCC 2705 are among the most studied probiotics. However, the first evidence of acyl hydrolase/lipase of two annotated proteins, one in each genome of these strains, is reported in this work. Signal peptide analysis has predicted that these proteins are exported to the extracellular medium. Both proteins were produced in Escherichia coli, purified and characterized. Molecular masses (without signal peptides) were 27 and 52.3 kDa for the proteins of L. rhamnosus and B. longum, respectively. Asymmetrical flow field-flow fractionation analysis has shown that both proteins are present as monomers in their native forms at pH 7. Both have shown enzymatic activity on pNP-laurate at pH 7 and 37°C. The enzyme from L. rhamnosus was characterized deeper, showing preference on pNP-esters with short chain fatty acids. In addition, a computational model of the 3D structure has allowed the prediction of the catalytic amino acids. The enzymatic activities using synthetic substrates were very low for both enzymes. The investigation of natural substrates and biological functions of these enzymes is still open.
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