Julián Londoño-Londoño

Hesperidin and hesperetin membrane interaction: Understanding the role of 7-O-glycoside moiety in flavonoids

Citrus species contain various typical flavonoids. However, absorption and metabolism of flavonoids are complex processes that determine its bioavailability which remain not clear until now. The aim of this study was to investigate the interactions among dimyristoyl-phosphatidyl choline (DMPC) liposomes and the flavanones hesperidin (glycoside) and hesperetin (aglycone). The results describe the molecular details of these interactions and the consequences for the membranes properties, by using differential scanning calorimetry (DSC), atomic force microscopy (AFM), fluorescence (using MC540 as probe), X-ray diffraction and theoretical study. The results show that hesperetin interacts with membranes stronger than hesperidin. It is possible to hypostatize that hesperidin, due to its rutinoside moiety, is located at the level of polar head whereas hesperetin interacts better with acyl chains and adopts a more planar conformation. The findings of this work may contribute to explain the high bioavailability of aglycones due to better membrane interaction.

Citrus juice extraction systems: effect on chemical composition and antioxidant activity of clementine juice.

Clementines are especially appreciated for their delicious flavor, and recent years have seen a great increase in the consumption of clementine juice. In previous decades, antioxidant compounds have received particular attention because of widely demonstrated beneficial health effects. In this work, the organoleptic, volatile flavor, and antioxidant quality of clementine juice were studied with regard to the influence on them by different juice extraction systems: plug inside fruit and rotating cylinders. The results showed that juice extracted by the former method presented higher yields and hesperidin content, which was related to higher antioxidant activity, demonstrated by ORAC and LDL assays. The organoleptic quality was not affected by the processing technique, whereas there were significant differences in the chemical flavor profile. There are important differences in chemical and functional quality between juice extraction techniques, which must be taken into account when employing processing systems to produce high-quality products.

Proatherogenic macrophage activities are targeted by the flavonoid quercetin

Many studies have demonstrated that the flavonoid quercetin protects against cardiovascular disease (CVD) and related risk factors. Atherosclerosis, the underlying cause of CVD, is also attenuated by oral quercetin administration in animal models. Although macrophages are key players during fatty streak formation and plaque progression and aggravation, little is known about the effects of quercetin on atherogenic macrophages. Here, we report that primary bone marrow-derived macrophages internalized less oxidized low-density lipoprotein (oxLDL) and accumulated less intracellular cholesterol in the presence of quercetin. This reduction of foam cell formation correlated with reduced surface expression of the oxLDL receptor CD36. Quercetin also targeted the lipopolysaccharide-dependent, oxLDL-independent pathway of lipid droplet formation in macrophages. In oxLDL-stimulated macrophages, quercetin inhibited reactive oxygen species production and interleukin (IL)-6 secretion. In a system that evaluated cholesterol crystal-induced IL-1β secretion via nucleotide-binding domain and leucine-rich repeat containing protein 3 inflammasome activation, quercetin also exhibited an inhibitory effect. Dyslipidemic apolipoprotein E-deficient mice chronically treated with intraperitoneal quercetin injections had smaller atheromatous lesions, reduced lipid deposition, and less macrophage and T cell inflammatory infiltrate in the aortic roots than vehicle-treated animals. Serum levels of total cholesterol and the lipid peroxidation product malondialdehyde were also reduced in these mice. Our results demonstrate that quercetin interferes with both key proatherogenic activities of macrophages, namely foam cell formation and pro-oxidant/proinflammatory responses, and these effects may explain the atheroprotective properties of this common flavonoid.

Quantification of phytoprostanes – bioactive oxylipins – and phenolic compounds of Passiflora edulis Sims shell using UHPLC-QqQ-MS/MS and LC-IT-DAD-MS/MS

The genus Passiflora, comprising about 500 species, is the largest in the Passion flower family. Passiflora edulis Sims f. edulis (gulupa) is one of the most important fruits cultivated in Colombia. In recent years and due to its organoleptic and bioactive properties, its exports have significantly increased. In this work, six new bioactive oxylipins -phytoprostanes - were detected in gulupa shell by a UHPLC-QqQ-MS/MS method: F1t-phytoprostanes and D1t-phytoprostanes were the predominant and minor classes, respectively. Moreover, the polyphenol profile of the shell was investigated and we were able to detect and quantify phenolic compounds that have not been described previously, like luteolin-8-C-(2-O-rhamnosyl)hexoside and quercetin-3-O-(6″-acetyl)glucosyl-2″-sinapic acid. Consequently, this study provides new insights into the importance of gulupa shell as a valuable option in the design of new beverages rich in antioxidant phytochemicals, as part of a well-balanced diet, and in the process and quality control of such products.

Natural Biflavonoids Modulate Macrophage–Oxidized LDL Interaction In Vitro and Promote Atheroprotection In Vivo

The accumulation of oxidized ApoB-100-containing lipoproteins in the vascular intima and its subsequent recognition by macrophages results in foam cell formation and inflammation, key events during atherosclerosis development. Agents targeting this process are considered potentially atheroprotective. Since natural biflavonoids exert antioxidant and anti-inflammatory effects, we evaluated the atheroprotective effect of biflavonoids obtained from the tropical fruit tree Garcinia madruno. To this end, the pure biflavonoid aglycones morelloflavone (Mo) and volkensiflavone (Vo), as well as the morelloflavone’s glycoside fukugiside (Fu) were tested in vitro in primary macrophages, whereas a biflavonoid fraction with defined composition (85% Mo, 10% Vo, and 5% Amentoflavone) was tested in vitro and in vivo. All biflavonoid preparations were potent reactive oxygen species (ROS) scavengers in the oxygen radical absorbance capacity assay, and most importantly, protected low-density lipoprotein particle from both lipid and protein oxidation. In biflavonoid-treated macrophages, the surface expression of the oxidized LDL (oxLDL) receptor CD36 was significantly lower than in vehicle-treated macrophages. Uptake of fluorescently labeled oxLDL and cholesterol accumulation were also attenuated in biflavonoid-treated macrophages and followed a pattern that paralleled that of CD36 surface expression. Fu and Vo inhibited oxLDL-induced ROS production and interleukin (IL)-6 secretion, respectively, whereas all aglycones, but not the glucoside Fu, inhibited the secretion of one or more of the cytokines IL-1β, IL-12p70, and monocyte chemotactic protein-1 (MCP-1) in lipopolysaccharide (LPS)-stimulated macrophages. Interestingly, in macrophages primed with low-dose LPS and stimulated with cholesterol crystals, IL-1β secretion was significantly and comparably inhibited by all biflavonoid preparations. Intraperitoneal administration of the defined biflavonoid fraction into ApoE−/− mice was atheroprotective, as evidenced by the reduction of the atheromatous lesion size and the density of T cells and macrophages infiltrating the aortic root; moreover, this treatment also lowered the circulating levels of cholesterol and the lipid peroxidation product malondialdehyde. These results reveal the potent atheroprotective effects exerted by biflavonoids on key events of the oxLDL–macrophage interphase: (i) atheroligand formation, (ii) atheroreceptor expression, (iii) foam cell transformation, and (iv) prooxidant/proinflammatory macrophage response. Furthermore, our results also evidence the antioxidant, anti-inflammatory, hypolipemiant, and atheroprotective effects of Garcinia madruno’s biflavonoids in vivo.

Untargeted metabolomics reveals specific withanolides and fatty acyl glycoside as tentative metabolites to differentiate organic and conventional Physalis peruviana fruits

The agronomic production systems may affect the levels of food metabolites. Metabolomics approaches have been applied as useful tool for the characterization of fruit metabolome. In this study, metabolomics techniques were used to assess the differences in phytochemical composition between goldenberry samples produced by organic and conventional systems. To verify that the organic samples were free of pesticides, individual pesticides were analyzed. Principal component analysis showed a clear separation of goldenberry samples from two different farming systems. Via targeted metabolomics assays, whereby carotenoids and ascorbic acid were analyzed, not statistical differences between both crops were found. Conversely, untargeted metabolomics allowed us to identify two withanolides and one fatty acyl glycoside as tentative metabolites to differentiate goldenberry fruits, recording organic fruits higher amounts of these compounds than conventional samples. Hence, untargeted metabolomics technology could be suitable to research differences on phytochemicals under different agricultural management practices and to authenticate organic products.

Passive Sampling to Monitor Hazardous Compounds in Water: A Tool for the Risk Assessment of Consuming Aquatic Food

Abstract Heavy metals are toxic compounds, which in low quantities can cause severe damage to human health. Heavy metal compounds appear in water naturally, but some anthropogenic activities can generate large discharges. Once in the water bodies, these compounds dilute and remain in quantities that are difficult to detect with most common analytical procedures. Therefore, the monitoring of inorganic pollutants is an ongoing challenge for the analytical chemistry. To establish the quality of different compartments of our environment, a relatively large number of samples must be taken from a given location over the entire duration of sampling when conventional sampling methods are applied. This type of approach to sampling is time-consuming and can be very costly. Passive sampling is a developing technique that is based on the flow of the analyte from the aquatic medium to a receiving phase due to the difference on their chemical potentials. Compared to others, this technique presents relative advantages such as preconcentration of the analyte and protection of the analyte. This chapter presents the conceptual principles involved in passive sampling and proposes it as a useful tool to monitor potential risks associated with heavy metal ingestion, in both drinking water and fish.

Microencapsulation of lutein by spray-drying: Characterization and stability analyses to promote its use as a functional ingredient

Lutein, a xanthophyll, is associated to decreased risk of age-related macular degeneration, atherosclerosis and other diseases (Bovier et al., 2013; El-raey, Ibrahim, & Eldahshan, 2013). When lutein is extracted, it becomes highly unstable, reducing its functionality as an antioxidant. The aim of this research was to improve the stability of lutein using maltodextrin, arabic gum and a modified starch, to obtain micro-particles using spray-drying. Each of the formulations was characterized in terms of yield, encapsulation efficiency, particle size distribution, water activity and moisture content. The formulations with arabic gum (100%) and arabic gum:maltodextrin:modified starch (33.3:33.3:33.3%), with encapsulation efficiencies of 91.94 ± 6.88 and 65.72 ± 0.93%, respectively, were selected to study stability at 45 °C and 75% RH (relative humidity). Based on our results, encapsulation could be considered as an alternative for the generation of high value-added functional ingredients that can be used in different industries.