Ultra high performance liquid chromatography with ion-trap TOF-MS for the fast characterization of flavonoids in Citrus bergamia juice

Bergamot and olive extracts as beer ingredients: their influence on nutraceutical and sensory properties

Citrus bergamia and Olea europaea L. variety Carolea are accounted as niche functional food for their high content of bio active compounds. Their extracts were used as adjunct to produce two beers with different styles, Blanche and Weiss, rich in antioxidants for a pool of consumers interested in a healthy lifestyle. The nutraceutical properties of these two beers were compared to Blanche and Weiss without any addition to verify if the beers enriched with natural extracts changed their aromaticity, flavors, and functionality. The antioxidant activity changed in the order: blanche bergamot beer > Weiss olive beer > blanche basal beer > Weiss basal beer. The phenolic profile of bergamot beer was qualitatively and quantitatively the richest in bio-compounds. Pearson’s correlation evidenced that total phenols contained in bergamot and olive beers were positively and significantly correlated with the antioxidant activities and precisely, with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and total antioxidant capacity (TAC). Correlation data evidenced that the bergamot was the beer with the greatest antioxidant activity and bioactive compound amount. This study highlighted as the addition of these natural extracts together with the right productive process improved sensorial beer properties, satisfying consumer taste while potentially increasing the beneficial effects on human health.

Evaluation of lipid and cholesterol-lowering effect of bioflavonoids from bergamot extract

Several natural products have been reported to be involved in the suppression of adipogenesis. In this study, we reveal that a bergamot extract (BE) decreased the accumulation of intracellular lipids in murine pre-adipocytes 3T3-L1 cells during adipogenic differentiation. Both the inhibition of HMG-CoA reductase activity and the differentiation and proliferation of adipocytes could be used as a strategy for the treatment and prevention of obesity. The results of this study show a reduction of HMG-CoA activity and of lipid droplet accumulation in the presence of the BE, suggesting the potential of BE as an anti-adipogenic agent to lower the content of cholesterol and body fat and prevent a gain in body weight. Moreover, BE as the result of high percentages of flavonoid compounds such as neoriocitrin, naringin and neohesperidin, the main flavonoids contained in BE, led to significant inhibition of DPPH free radical, demonstrating a strong radical scavenging activity.

Polyphenolic Extract from Tarocco (Citrus sinensis L. Osbeck) Clone "Lempso" Exerts Anti-Inflammatory and Antioxidant Effects via NF-kB and Nrf-2 Activation in Murine Macrophages

Citrus fruits are often employed as ingredients for functional drinks. Among Citrus, the variety, “Lempso”, a typical hybrid of the Calabria region (Southern Italy), has been reported to possess superior antioxidant activity when compared to other common Citrus varieties. For these reasons, the aim of this study is to investigate in vitro the nutraceutical value of the Tarocco clone, “Lempso”, highlighting its anti-inflammatory and antioxidant potential. A post-column 2,2′-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay for the screening of antioxidant compounds in these complex matrices was developed. Subsequently, polyphenolic extract was tested on a murine macrophage cell line under inflammatory conditions. The extract resulted was able to significantly inhibit nitric oxide (NO) and cytokine release and inducible nitric oxide synthase (iNOS) and cycloxygenase-2 (COX-2) expression. The inhibition of these pro-inflammatory factors was associated to Nuclear factor-kB (NF-kB) inhibition. Our results also indicate an anti-oxidant potential of the extract as evidenced by the inhibition of reactive oxygen species (ROS) release and by the activation of the nuclear factor E2-related factor-2 (Nrf-2) pathway in macrophages. The obtained results highlight the anti-inflammatory and antioxidant potential of Lempso extract and its potential use, as a new ingredient for the formulation of functional beverages with high nutraceutical value, providing health benefits to consumers.

Qualitative and Quantitative Analyses of Active Constituents in Trollius ledebourii

Trollius ledebourii has been more involved in Mongolian medicine and is often used as a type of tea for heat-clearing and detoxifying in the populus. In this study, a rapid and sensitive method was established for the qualitative and quantitative analyses of the major constituents in T. ledebourii. Ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was developed for the identification of the multi-constituents in T. ledebourii. A total of 37 chemical constituents in T. ledebourii extract were unambiguously or tentatively identified, including 17 flavonoid glycosides, 6 flavones, 3 flavonols, 1 dihydroflavone, 8 phenolic acids, 1 amide and 1 triterpene. Pectolinarin, naringenin, isorhamnetin, diosmetin, protocatechuic acid, paeonol, caffeic acid and ferulic acid were first detected in T. ledebourii and the buttercup family. High-performance liquid chromatography-quadrupole ion trap tandem mass spectrometry was applied for the simultaneous determination of 11 compounds, which were either with high contents or strong bioactivities. Satisfactory linearity was achieved with a wide linear range and fine determination coefficient (r > 0.9987). The overall recoveries ranged from 98.07 to 101.2%, and the precision in terms of RSD was <0.74%. The results might provide the basis for quality control analysis of T. ledebourii.

Bioavailability of Bergamot (Citrus bergamia) Flavanones and Biological Activity of Their Circulating Metabolites in Human Pro-Angiogenic Cells

Myeloid angiogenic cells (MACs) play a key role in endothelial repairing processes and functionality but their activity may be impaired by the lipotoxic effects of some molecules like stearic acid (SA). Among the dietary components potentially able to modulate endothelial function in vivo, (poly)phenolic compounds represent serious candidates. Here, we apply a comprehensive multidisciplinary approach to shed light on the prospects of Bergamot (Citrus bergamia), a citrus fruit rich in flavanones and other phenolic compounds, in the framework of lipotoxicity-induced MACs impairment. The flavanone profile of bergamot juice was characterized and 16 compounds were identified, with a new 3-hydroxy-3-methylglutaryl (HMG) flavanone, isosakuranetin-7-O-neohesperidoside-6″-O-HMG, described for the first time. Then, a pilot bioavailability study was conducted in healthy volunteers to assess the circulating flavanone metabolites in plasma and urine after consumption of bergamot juice. Up to 12 flavanone phase II conjugates (sulfates and glucuronides of hesperetin, naringenin and eriodyctiol) were detected and quantified. Finally, the effect of some of the metabolites identified in vivo, namely hesperetin-7-O-glucuronide, hesperetin-3′-O-glucuronide, naringenin-7-O-glucuronide and naringenin-4′-O-glucuronide, was tested, at physiological concentrations, on gene expression of inflammatory markers and apoptosis in MACs exposed to SA. Under these conditions, naringenin-4′-O-glucuronide and hesperetin-7-O-glucuronide were able to modulate inflammation, while no flavanone glucuronide was effective in curbing stearate-induced lipoapoptosis. These results demonstrate that some flavanone metabolites, derived from the in vivo transformation of bergamot juice phenolics in humans, may mitigate stearate-induced inflammation in MACs.

Flavonoid Composition of Tarocco (Citrus sinensis L. Osbeck) Clone "Lempso" and Fast Antioxidant Activity Screening by DPPH-UHPLC-PDA-IT-TOF

INTRODUCTION

Clonal selection and hybridisation are valid strategies to obtain fruits with enhanced sensorial and nutraceutical properties. Within Citrus sinensis varieties, Tarocco clone "Lempso" is a typical product of the Calabria region (Italy) characterised by its red pulp. This is the first report concerning its accurate profiling.

OBJECTIVE

To characterise in detail the flavonoid composition of Lempso clone and to compare its antioxidant potential with other Citrus varieties by a fast screening method.

METHODOLOGY

Extracts were subjected to solid phase extraction and the qualitative/quantitative profile was elucidated through ultra-high performance liquid chromatography (UHPLC) coupled to photodiode array (PDA) and ion trap time-of-flight (IT-TOF) mass spectrometry detection, and compared to both Cleopatra mandarin (Citrus reticulata) and blood orange (Citrus sinensis (L.) Osbeck) Sanguinello varieties. The antioxidant activity was assessed by pre-column 2,2'-diphenyl-1-picrylhydrazyl (DPPH) reaction coupled to UHPLC-PDA.

RESULTS

Lempso is characterised by flavonoids (17) and anthocyanins (8). Flavanones content (Hesperidin: 57.19 ± 0.49, Vicenin-2: 4.59 ± 0.03, Narirutin: 5.78 ± 0.13 mg/100 mL) was considerably higher than Cleopatra and Sanguinello varieties. The developed DPPH-UHPLC-PDA method provides information regarding the single contributions to antioxidant activity, highlighting how Ferulic acid, Quercetin and Cyanidin derivatives possess considerable radical scavenging activity (> 50%). The total antioxidant activity was also evaluated and compared with positive controls, showing higher scavenging activity than Cleopatra and Sanguinello (IC₅₀ : 333.76 ± 10.81 μg/mL vs. 452.62 ± 10.81 and 568.39 ± 26.98 μg/mL, respectively).

CONCLUSION

These data evidence the nutraceutical potential of Lempso variety, which could be an ingredient for functional beverages. Copyright © 2017 John Wiley & Sons, Ltd.

Liquid chromatography-high resolution mass spectrometry for the analysis of phytochemicals in vegetal-derived food and beverages

The recent years witnessed a change in the perception of nutrition. Diet does not only provide nutrients to meet the metabolic requirements of the body, but it also constitutes an active way for the consumption of compounds beneficial for human health. Fruit and vegetables are an excellent source of such compounds, thus the growing interest in characterizing phytochemical sources, structures and activities. Given the interest for phytochemicals in food, the development of advanced and suitable analytical techniques for their identification is fundamental for the advancement of food research. In this review, the state of the art of phytochemical research in food plants is described, starting from sample preparation, throughout extract clean-up and compound separation techniques, to the final analysis, considering both qualitative and quantitative investigations. In this regard, from an analytical point of view, fruit and vegetable extracts are complex matrices, which greatly benefit from the use of modern hyphenated techniques, in particular from the combination of high performance liquid chromatography separation and high resolution mass spectrometry, powerful tools which are being increasingly used in the recent years. Therefore, selected applications to real samples are presented and discussed, in particular for the analysis of phenols, polyphenols and phenolic acids. Finally, some hot points are discussed, such as waste characterization for high value-compounds recovery and the untargeted metabolomics approach.

Detailed polyphenolic profiling of Annurca apple (M. pumila Miller cv Annurca) by a combination of RP-UHPLC and HILIC, both hyphenated to IT-TOF mass spectrometry

Annurca apple, a Southern Italian cultivar, possesses not only a particular taste and flavor, different from other types of apple, but also several healthy properties. With the aim to thoroughly elucidate the polyphenolic profile of this variety, listed as Protected Geographical Indication product, an extensive qualitative profiling of Annurca apple polyphenolic peel extract was carried out, by employing a combination of ultra high performance reversed phase (RP-UHPLC) and hydrophilic liquid chromatography (HILIC) coupled to ion trap-time of flight (IT-TOF) mass spectrometry. A total of 63 compounds were tentatively identified, 25 of which not reported in Annurca apple extract so far. Furthermore, thanks to the different selectivity obtained with the HILIC, in combination with accurate mass measurements, an improved separation and detection of procyanidins, was obtained. Moreover, the obtained profiles were compared with those of a conventional variety, such as Red Delicious (RD), highlighting their differences. This work contributes to increase the knowledge about the polyphenolic fingerprint of this typical apple variety.

Profiling of phenolic and other compounds from Egyptian cultivars of chickpea (Cicer arietinum L.) and antioxidant activity: a comparative study

The metabolic profiling of seven Egyptian cultivars of chickpeaviaRP-HPLC-DAD-ESI-QTOF-MS enabled the characterization of 96 phenolic compounds.

Liquid chromatography with mass spectrometry method based two-step precursor ion scanning for the structural elucidation of flavonoids

Plant flavonoids are very important secondary metabolites for insect and virus control of their host plant and are potent nutrients for humans. To be able to understand the bioavailability and functions of plant flavonoids, it is necessary to reveal their exact chemical structures. Liquid chromatography with tandem mass spectrometry is a powerful approach for structural elucidation of metabolites. In this report, a two-step precursor ion scanning based liquid chromatography with tandem mass spectrometry method was developed for the structural elucidation of plant flavonoids. The established method consists of the two-step precursor ions scanning for possible flavonoids extraction, MS(2) fragment spectra acquisition and comparison with an online database, liquid chromatography retention rules correction, and commercial standards verification. The developed method was used for the structure elucidation of flavonoids in flowers and leaves of tobacco (Nicotiana tabacum), and 17 flavonoids were identified in the tobacco variety Yunyan 97. Nine of the 17 identified flavonoids were considered to be found in tobacco flowers or/and leaves for the first time based on the available references. This method was proved to be very effective and can be used for the identification of flavonoids in other plants.

Flavonoid fraction of Bergamot juice reduces LPS-induced inflammatory response through SIRT1-mediated NF-κB inhibition in THP-1 monocytes

Plant polyphenols exert anti-inflammatory activity through both anti-oxidant effects and modulation of pivotal pro-inflammatory genes. Recently, Citrus bergamia has been studied as a natural source of bioactive molecules with antioxidant activity, but few studies have focused on molecular mechanisms underlying their potential beneficial effects. Several findings have suggested that polyphenols could influence cellular function by acting as activators of SIRT1, a nuclear histone deacetylase, involved in the inhibition of NF-κB signaling. On the basis of these observations we studied the anti-inflammatory effects produced by the flavonoid fraction of the bergamot juice (BJe) in a model of LPS-stimulated THP-1 cell line, focusing on SIRT1-mediated NF-κB inhibition. We demonstrated that BJe inhibited both gene expression and secretion of LPS-induced pro-inflammatory cytokines (IL-6, IL-1β, TNF-α) by a mechanism involving the inhibition of NF-κB activation. In addition, we showed that BJe treatment reversed the LPS-enhanced acetylation of p65 in THP-1 cells. Interestingly, increasing concentrations of Sirtinol were able to suppress the inhibitory effect of BJe via p65 acetylation, underscoring that NF-κB-mediated inflammatory cytokine production may be directly linked to SIRT1 activity. These results suggest that BJe may be useful for the development of alternative pharmacological strategies aimed at reducing the inflammatory process.