Recent advances and trends in the liquid-chromatography–mass spectrometry analysis of flavonoids

Insights on the Extraction and Analysis of Phenolic Compounds from Citrus Fruits: Green Perspectives and Current Status

Citrus fruits (CF) are highly consumed worldwide, fresh, processed, or prepared as juices and pies. To illustrate the high economic importance of CF, the global production of these commodities in 2021 was around 98 million tons. CF's composition is considered an excellent source of phenolic compounds (PC) as they have a large amount and variety. Since ancient times, PC has been highlighted to promote several benefits related to oxidative stress disorders, such as chronic diseases and cancer. Recent studies suggest that consuming citrus fruits can prevent some of these diseases. However, due to the complexity of citrus matrices, extracting compounds of interest from these types of samples, and identifying and quantifying them effectively, is not a simple task. In this context, several extractive and analytical proposals have been used. This review discusses current research involving CF, focusing mainly on PC extraction and analysis methods, regarding advantages and disadvantages from the perspective of Green Chemistry.

The effects of modifiers on electrospray ionization for small-to-medium-sized molecules in comparison with solution-phase ionization

Modifiers are essential additives in electrospray ionization (ESI) mass spectrometric analysis to enhance the production of ionic species in the gas phase for the detection of small-to-medium-sized molecules in biological and aqueous samples. Therefore, an appropriate modifier, in conjunction with the right ionization polarity, is crucial for sensitive ESI mass spectrometric analysis. However, the charge carried by basic and acidic functional groups in solution is neither quantitatively nor qualitatively reflected in the MS spectrum. For example, adding an acidic modifier will cause sufficient protonation of a basic functional group in solution; however, this may result in inferior positive ESI compared to using a basic modifier. Another example is when the MS spectrum does not reflect the charge distribution of multiply charged molecules in solution. Therefore, this review will summarize and discuss the proposed mechanisms by which modifiers induce and influence ESI. It will also cover molecular characteristics that affect ESI, such as charge state and polarity, which result in a difference between solution-phase ionization and ESI.

Assessment of multi-biomedical efficiency of Andrographis paniculata shoot extracts through in-vitro analysis and major compound identification

The present investigation looked into the various biomedical potentials of Andrographis paniculata shoot extracts. The results showed that the methanol extract (Met-E) of A. paniculata contains more phytochemicals than the acetone and petroleum ether extracts, including alkaloids, saponins, tannins, phenolics, flavonoids, glycosides, terpenoids, phytosterol, steroids, and protein. Accordingly, the Met-E alone showed considerable bactericidal activity (through agar well diffusion method) against the bacterial pathogens namely Shigella dysenteriae, Bacillus cereus, Salmonella typhi, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphlococcus aureus, E. coli, and B. subtilis. This bactericidal activity was found as dose dependent manner, since at 1000 μg ml concentration, the Met-E showed better antibacterial activity. Similarly, at increased concentration (1000 μg ml) it showed notable antidiabetic (α-amylase inhibition: 74.31% and α-glucosidase inhibition: 72.34%), antioxidant (DPPH: 78.24%), and anti-inflammatory (albumin denaturation inhibition: 79.84% and lipoxigenase inhibition: 69.4%) activities. The phytochemical profiling of Met-E was characterized by UV-visible spectrophotometer (UV-vis), Gas Chromatography-Mass Spectrometry (GC/MS), Fourier transform infrared (FTIR), and High Performance Liquid Chromatography (HPLC) analyses. The results showed the Met-E contain bioactive compounds such as gallic acid, epicatechin, catechin, naringin, vitexin-2-rhamnoside, taxifolin, kaempferol, hesperidin, myricetin, rutin, quercetin, phloretin, and ursolic acid compounds. While most of these substances have been recognised for their pharmacological application perspective, the biological properties of particular substances must be studied in the future using in-vivo strategies.

A perspective on the use of deep deterministic policy gradient reinforcement learning for retention time modeling in reversed-phase liquid chromatography

Artificial intelligence and machine learning techniques are increasingly used for different tasks related to method development in liquid chromatography. In this study, the possibilities of a reinforcement learning algorithm, more specifically a deep deterministic policy gradient algorithm, are evaluated for the selection of scouting runs for retention time modeling. As a theoretical exercise, it is investigated whether such an algorithm can be trained to select scouting runs for any compound of interest allowing to retrieve its correct retention parameters for the three-parameter Neue-Kuss retention model. It is observed that three scouting runs are generally sufficient to retrieve the retention parameters with an accuracy (mean relative percentage error MRPE) of 1 % or less. When given the opportunity to select additional scouting runs, this does not lead to a significantly improved accuracy. It is also observed that the agent tends to give preference to isocratic scouting runs for retention time modeling, and is only motivated towards selecting gradient scouting runs when penalized (strongly) for large analysis/gradient times. This seems to reinforce the general power and usefulness of isocratic scouting runs for retention time modeling. Finally, the best results (lowest MRPE) are obtained when the agent manages to retrieve retention time data for % ACN at elution of the compound under consideration that spread the entire relevant range of ACN (5 % ACN to 95 % ACN) as well as possible, i.e., resulting in retention data at a low, intermediate and high % ACN. Based on the obtained results, we believe reinforcement learning holds great potential to automate and rationalize method development in liquid chromatography in the future.

Advancing the analytical toolkit in the investigation of vector mosquito host biting site selection

High-resolution mass spectrometry and ion mobility spectrometry provide additional confidence in biological marker discovery and elucidation by adding additional peak capacity through physiochemical separation orthogonal to chromatography. Sophisticated analytical techniques have proved valuable in the identification of human skin surface chemicals used by vector mosquitoes to find their human host. Polydimethylsiloxane (PDMS) was used as a non-invasive passive wearable sampler to concentrate skin surface non-volatile and semi-volatile compounds prior to solvent desorption directly in an LC vial, thereby simplifying the link between extraction and analysis. Ultra-performance liquid chromatography with ion mobility spectrometry coupled with high-resolution mass spectrometry (UPLC-IMS-HRMS) was used for compound separation and detection. A comparison of the skin chemical profiles between the ankle and wrist skin surface region sampled over a 5-day period for a human volunteer was done. Twenty-three biomarkers were tentatively identified with the aid of a collision cross-section (CCS) prediction tool, seven associated with the ankle skin surface region and 16 closely associated with the wrist skin surface. Ten amino acids were detected and unequivocally identified on the human skin surface for the first time. Furthermore, 22 previously unreported skin surface compounds were tentatively identified on the human skin surface using accurate mass, CCS values and fragmentation patterns. Method limits of detection for the passive skin sampling method ranged from 8.7 (sulfadimethoxine) to 95 ng (taurine). This approach enabled the detection and identification of as-yet unknown human skin surface compounds and provided corresponding CCS values.

Luteolin: Nature's promising warrior against Alzheimer's and Parkinson's disease

Neurodegenerative disorders (NDs) are defined as the slow loss of a group of neurons that are particularly sensitive. Due to the intricate pathophysiological processes underlying neurodegeneration, no cure exists for these conditions despite the extensive research and advances in our knowledge of the onset and course of NDs. Hence, there is a medical need for the creation of a novel therapeutic approach for NDs. By focusing on numerous signaling pathways, some natural substances derived from medicinal herbs and foods have demonstrated potent activity in treating various NDs. In this context, flavonoids have recently attracted increased popularity and research attention because of their alleged beneficial effects on health. By acting as antioxidant substances, nutritional supplements made up of flavonoids have been found to lessen the extent of NDs like Alzheimer's disease (AD) and Parkinson's disease (PD). Luteolin is a flavone that possesses potent antioxidant and anti-inflammatory properties. As a consequence, luteolin has emerged as an option for treatment with therapeutic effects on many brain disorders. More research has focused on luteolin's diverse biological targets as well as diverse signaling pathways, implying its potential medicinal properties in several NDs. This review emphasizes the possible use of luteolin as a drug of choice for the treatment as well as the management of AD and PD. In addition, this review recommends that further research should be carried out on luteolin as a potential treatment for AD and PD alongside a focus on mechanisms and clinical studies.

Comprehensive Analysis of Chemical Ingredients of Waiganfengsha Granule and Absorbed Components in Rat Plasma Based on UHPLC-Q-TOF-MS

OBJECTIVE

Waiganfengsha Granule, an over-the-counter drug, is commonly used for treating windheat cold and sore throat in clinical settings. However, its material basis of medicinal efficacy is still unclear. In this study, an efficient integrated analytical strategy was established for its chemical and metabolite profiles study.

METHODS

Firstly, to avoid the possible false-positive results of structural elucidation, an in-house component library that contains chemical constituents reported in the literature from the six individual medicines of Waiganfengsha Granule was established. Secondary, mass data post-processing techniques, including precursor ion list and neutral loss filtering, were applied to enhance the identification accuracy. Thirdly, for the rapid characterization of those absorbed components after oral administration in rats, the identified chemical constituents were used as candidate components for the serum analysis. By comparing the retention time and analyzing mass data, the metabolites in rat plasma were identified.

RESULTS

As a result, 57 chemical ingredients were identified, including 21 phenolic acids, 9 alkaloids, 2 flavonoids, 5 lignins, 13 saponins, and 7 other compounds. Among these, 12 compounds were unambiguously identified by comparison with reference standards, and 45 were tentatively characterized by analyzing their accurate MS data, MS/MS fragmentation patterns, and also by comparison with those data reported in the literature. Additionally, 46 metabolites were detected and identified in rat plasma.

CONCLUSION

This study is beneficial for understanding the chemical composition and metabolic profiles of Waiganfengsha Granule, and the results obtained might provide a solid basis for further studies on its functional mechanism.

Progress in the design of portable colorimetric chemical sensing devices

The need for precise determination of heavy metals, anions, biomolecules, pesticides, drugs, and other substances is vital across clinical, environmental, and food safety domains. Recent years have seen significant progress in portable colorimetric chemical sensing devices, revolutionizing on-the-spot analysis. This review offers a comprehensive overview of these advancements, covering handheld colorimetry, RGB-based colorimetry, paper-based colorimetry, and wearable colorimetry devices. It explores the underlying principles, functional materials (chromophoric reagents/dyes and nanoparticles), detection mechanisms, and their applications in environmental monitoring, clinical care, and food safety. Noble metal nanoparticles (NPs) have arisen as promising substitutes in the realm of sensing materials. They display notable advantages, including heightened sensitivity, the ability to fine-tune their plasmonic characteristics for improved selectivity, and the capacity to induce visible color changes, and simplifying detection. Integration of NPs fabricated paper device with smartphones and wearables facilitates reagent-free, cost-effective, and portable colorimetric sensing, enabling real-time analysis and remote monitoring.

Comprehensive quantification of flavonoids and salicylic acid representative of Salix spp. using microLiquid Chromatography-Triple Quadrupole Mass Spectrometry: the importance of drying procedures and extraction solvent when performing classical solid-liquid extraction

Willow (Salix spp.) is gaining an increasing interest as a fast-growing tree with high biomass yield from low agricultural inputs, which contains potentially bioactive compounds. The present work aimed to develop a high-yield extraction procedure combined with robust, sensitive and fast microLiquid Chromatography-Triple Quadrupole Mass Spectrometry (LC-MS/MS) based method for comprehensively quantifying flavonoids and salicylic acid in the bark of Salix spp. We have investigated the effect of freeze- and oven-drying procedures and five extraction solvents on the yield of individual flavonoid and salicylic acid when performing classical solid-liquid extraction. The freeze-drying was the best drying procedure for preserving monomeric and polymeric flavan-3-ols, whereas other flavonoids were less affected. Salicylic acid was not affected by the drying procedures. The best extraction solvent in terms of the yield of individual flavonoid among the tested solvents in this study was the combination of methanol acidified with 1% hydrochloric acid. LC-MS/MS method has shown a high recovery percentage (≥80%), good precision and overall robustness.

An Interdisciplinary Assessment of Biochemical and Antioxidant Attributes of Six Greek Vicia sativa L. Varieties

Common vetch (Vicia sativa L.) is one of the most cultivated feed crops with extensive agricultural diversity and numerous cultivars. This study concerns the first-time investigation of the dry plant biomass and grains of six vetch cultivars to define the detailed fingerprint of their phenolic and fatty acid content, along with their respective antioxidant potencies. The results revealed a substantial variation in the feed quality traits among the tested Vicia sativa varieties, highlighting the crucial role and influence the genotype plays in the achievement of high-quality livestock nutrition. Among the six varieties tested, Istros and M-6900 displayed a particularly intriguing phytochemical profile characterized by elevated phenolic content, significant antioxidant potency and remarkably high fatty acid indices. These findings are indicative of the great potential of these varieties to function as suitable candidates for incorporation into farm animal diets either in the form of dry biomass (hay) or as a grain feed additive.

Metabolite Profiling of External and Internal Petals in Three Different Colors of Tea Flowers (Camellia sinensis) Using Widely Targeted Metabolomics

The flower is the reproductive organ of the tea plant, while it is also processed into different kinds of products and thus of great significance to be utilized. In this study, the non-volatile secondary metabolites in the internal and external petals of white, white and pink, and pink tea flowers were studied using a widely targeted metabolomics method with ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A total of 429 metabolites were identified, including 195 flavonoids, 121 phenolic acids, 40 alkaloids, 29 lignans and coumarins, 19 tannins, 17 terpenoids, and 8 other metabolites. The metabolites in the internal and external petals of different colored flowers showed great changes in flavonoids. Most flavonoids and all tannins in the internal petals were higher compared with the external petals. Some phenolic acids were more accumulated in the external petals, while others showed opposite trends. The pink tea flower contained more flavonoids, alkaloids, lignans, coumarins, terpenoids, and tannins compared with white tea flowers. In addition, cyanidin-3-O-glucoside was more accumulated in the external petals of the pink flower, indicating that anthocyanin may be the main reason for the color difference between the pink and white tea flower. The enriched metabolic pathways of different colored flowers were involved in flavonoid biosynthesis, glycine, serine and threonine metabolism, glycerophospholipid metabolism, and phenylpropanoid biosynthesis. The findings of this study broaden the current understanding of non-volatile compound changes in tea plants. It is also helpful to lay a theoretical foundation for integrated applications of tea flowers.

Evolution of anthocyanin content during grape ripening and characterization of the phenolic profile of the resulting wine by comprehensive two-dimensional liquid chromatography

The typical phenolic profile in grapes is characterized by its complexity both in terms of number of diverse chemical structures and their variation during ripening. Besides, the specific phenolic composition of grapes directly influences the presence of those components in the resulting wine. In this contribution, a new method based on the application of comprehensive two-dimensional liquid chromatography coupled to a diode array detector and tandem mass spectrometry has been developed to obtain the typical phenolic profile of Malbec grapes cultivated in Brazil. Moreover, the method has been demonstrated to be useful to study how the phenolic composition in grapes evolved during a 10-week ripening period. Main detected compounds in grapes and in the wine derived from them were anthocyanins, although a good number of polymeric flavan-3-ols were also tentatively identified, among other compounds. Results show how the amount of anthocyanins present in grapes was increased during ripening up to 5-6 weeks and then decreased towards week 9. The two-dimensional approach applied was demonstrated to be useful for the characterization of the complex phenolic profile of these samples, involving more than 40 different structures and has the potential to be further applied to the study of this important fraction is different grapes and wines systematically.

Time-Series-Dependent Global Data Filtering Strategy for Mining and Profiling of Xenobiotic Metabolites in a Dynamic Complex Matrix: Application to Biotransformation of Flavonoids in the Extract of Ginkgo biloba by Gut Microbiota

Efficient characterization of xenobiotic metabolites and their dynamics in a changing complex matrix remains difficult. Herein, we proposed a time-series-dependent global data filtering strategy for the rapid and comprehensive characterization of xenobiotic metabolites and their dynamic variation based on metabolome data. A set of data preprocessing methods was used to screen potential xenobiotic metabolites, considering the differences between the treated and control groups and the fluctuations over time. To further identify metabolites of the target, an in-house accurate mass database was constructed by potential metabolic pathways and applied. Taking the extract of Ginkgo biloba (EGB) co-incubated with gut microbiota as an example, 107 compounds were identified as flavonoid-derived metabolites (including 67 original from EGB and 40 new) from 7468 ions. Their temporal metabolic profiles and regularities were also investigated. This study provided a systematic and feasible method to elucidate and profile xenobiotic metabolism.

The recovery from agro-industrial wastes provides different profiles of anti-inflammatory polyphenols for tailored applications

Food and agro-industrial processing produce a great amount of side-stream and waste materials that are excellent sources of functional bioactive molecules such as phenolic compounds that recover them can be beneficial not only for food sustainability but also to human for many industrial applications such as flavor compounds and therapeutic applications such as antimicrobial and anti-inflammatory. The treatments and extraction techniques have major effects on the recovery of bioactive compounds. Along with the conventional extraction methods, numerous innovative techniques have been evolved and have been optimized to facilitate bioactive extraction more efficiently and sustainably. In this work, we have summarized the state-of-the-art technological approaches concerning novel extraction methods applied for five most produced crops in Italy; Grape Pomace (GP), Tomato Pomace (TP), Olive Pomace (OP), Citrus Pomace (CP), and Spent Coffee Grounds (SCG), presenting the extraction yield and the main class of phenolic classes, with the focus on their biological activity as an anti-inflammatory in vitro and in vivo studies via describing their molecular mechanism of action.

UHPLC-Q-Exactive Orbitrap MS/MS-Based Untargeted Metabolomics and Molecular Networking Reveal the Differential Chemical Constituents of the Bulbs and Flowers of Fritillaria thunbergii

Both the bulbs and flowers of Fritillaria thunbergii Miq. (BFT and FFT) are widely applied as expectorants and antitussives in traditional Chinese medicine, but few studies have been conducted to compare the chemical compositions of these plant parts. In this study, 50% methanol extracts of BFT and FFT were analyzed via UHPLC-Q-Exactive Orbitrap MS/MS, and the feasibility of using non-targeted UHPLC-HRMS metabolomics and molecular networking to address the authentication of bulb and flower samples was evaluated. Principal component analysis (PCA), Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA), and heat map analysis showed there were dissimilar metabolites in BFT and FFT. As a result, 252 and 107 peaks in positive ion mode and negative mode, respectively, were considered to represent significant difference variables between BFT and FFT. Then, MS/MS-based molecular networking of BFT and FFT was constructed to perform an in-depth characterization of the peaks using different variables. A total of 31 alkaloids with significant differences were annotated in this paper, including seven cis-D/E-vevanine without C20-OH and one trans-D/E-cevanine with C20-OH, thirteen trans-D/E-cevanine without C20-OH, five cevanine N-oxide, and five veratramine. Among the 31 alkaloids, eight alkaloids had higher FFT than BFT contents, while all the flavonoids identified in our work had greater FFT than BFT contents. The influence of different ingredients on the pharmacological activities of BFT and FFT should be investigated in future studies.

Biomedical and Antioxidant Potentialities in Chilli: Perspectives and Way Forward

Worldwide, since ages and nowadays, traditional medicine is well known, owing to its biodiversity, which immensely contributed to the advancement and development of complementary and alternative medicines. There is a wide range of spices, herbs, and trees known for their medicinal uses. Chilli peppers, a vegetable cum spice crop, are bestowed with natural bioactive compounds, flavonoids, capsaicinoids, phytochemicals, phytonutrients, and pharmacologically active compounds with potential health benefits. Such compounds manifest their functionality over solo-treatment by operating in synergy and consortium. Co-action of these compounds and nutrients make them potentially effective against coagulation, obesity, diabetes, inflammation, dreadful diseases, such as cancer, and microbial diseases, alongside having good anti-oxidants with scavenging ability to free radicals and oxygen. In recent times, capsaicinoids especially capsaicin can ameliorate important viral diseases, such as SARS-CoV-2. In addition, capsaicin provides an ability to chilli peppers to ramify as topical agents in pain-relief and also benefitting man as a potential effective anesthetic agent. Such phytochemicals involved not only make them useful and a much economical substitute to wonder/artificial drugs but can be exploited as obscene drugs for the production of novel stuffs. The responsibility of the TRPV1 receptor in association with capsaicin in mitigating chronic diseases has also been justified in this study. Nonetheless, medicinal studies pertaining to consumption of chilli peppers are limited and demand confirmation of the findings from animal studies. In this artifact, an effort has been made to address in an accessible format the nutritional and biomedical perspectives of chilli pepper, which could precisely upgrade and enrich our pharmaceutical industries towards human well-being.

Green comprehensive two-dimensional liquid chromatography (LC × LC) for the analysis of phenolic compounds in grape juices and wine

Grape juices and wines are rich in numerous groups of polyphenolic compounds which require a dedicated separation technique for such complex samples. LC × LC is considered the best technique for the analysis of such samples as it can achieve better resolution and higher peak capacity compared to 1D LC. The ever-growing demand for protecting the environment necessitates reducing or eliminating hazardous solvents to improve the environmental friendliness of analytical procedures. In this study, propylene carbonate was used as an eco-friendly mobile phase component in comprehensive two-dimensional liquid chromatography to analyze phenolic compounds in grape juices and a dealcoholized wine sample. Novel green RPLC × RPLC-DAD and RPLC × RPLC-MS methods were developed for the first time to identify phenolic compounds in five samples (two red grape juice samples, two white grape juice samples, and one dealcoholized wine sample). Four different RPLC × RPLC systems were developed; three systems were connected to a diode array detector (RPLC × RPLC-DAD), while the fourth system was connected to DAD and MS detectors (RPLC × RPLC-DAD-ESI-MS). Solvent X (propylene carbonate:ethanol, 60:40) was adopted as a green organic modifier in the first dimension (¹D) and methanol in the second dimension (²D). The practical peak capacity and the surface coverage were calculated as metrics to measure the separation performance of all proposed systems. The orthogonality values for the setups ranged from 0.64 to 0.92 when calculated by the convex hull method, and from 0.54 to 0.80 when calculated by the asterisk equations method. The practical peak capacity production rate ranged from 14.58 to 22.52 peaks/min. The results revealed that the phenolic compounds were separated efficiently with good coverage of the 2D separation space and high peak capacity. A total of 70 phenolic compounds were detected based on MS data and information from the literature.

Development and validation of ultra-high performance supercritical fluid chromatography method for quantitative determination of four target flavonoids components in citrus samples

A new method for the analysis of four target flavonoids in two kinds of citrus samples by ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed. Main variables affecting the UHPSFC separation were optimized, and under the optimized conditions the four target compounds (tangeretin, nobiletin, hesperetin and naringenin) can be separated within 10 min. The UHPSFC method allowed the determination of the four target compounds in the diluted stock solutions with limit of detection (LOD) ranging from 1.08 to 2.28 μg mL−1, and limit of quantification (LOQ) ranging from 1.45 to 4.52 μg mL−1, respectively. The coefficients of determination (R 2) of the calibration curves were higher than 0.9950. The recoveries of the four target compounds at three different concentrations were in the range of 82.4–117.6%. The validation results demonstrated that the proposed method is simple, accurate, time-saving and environment friendly, and it is applicable to a variety of complex samples such as medicine-food dual purpose herbs and functional foods.

Wild-Grown and Cultivated Glechoma hederacea L.: Chemical Composition and Potential for Cultivation in Organic Farming Conditions

Glechoma hederacea L. is a medicinal plant that is known in traditional medicine for its anti-inflammatory, antibacterial, antiviral, and anticancer properties. This study evaluated the potential for commercial production of G. hederacea and compared the chemical composition and activity of 70% ethanol extracts and steam-distilled essential oils from wild-grown and cultivated G. hederacea collected in different harvesting periods. The main compounds identified in the 70% ethanol extracts were phenolic acids (chlorogenic and rosmarinic acids) and flavonoid O-glycosides. The essential oil varied in the three accessions in the range of 0.32–2.98 mL/kg⁻¹ of dry weight. The extracts possessed potent antioxidant and anti-inflammatory properties in LPS-treated bone-marrow-derived macrophages. The results of flow cytometry show that extracts from different vegetation periods reduced the conversion of macrophages to the proinflammatory phenotype M1. The chemical composition varied the most with the different harvesting periods, and the most suitable periods were the flowering and vegetative phases for the polyphenolic compounds and essential oils, respectively. G. hederacea can be successfully grown under organic farming conditions, and cultivation does not significantly affect the chemical composition and biological activity compared to wild-grown plants.

Fast and Sensitive Determination of Bioflavonoids Using a New Analytical System Based on Label-Free Silver Triangular Nanoplates

Optical sensors based on silver triangular nanoplates (AgTNPs) are insufficiently studied as probes for the spectrophotometric determination of biologically active compounds. In the present article, an interaction between label-free AgTNPs and bioflavonoids in the presence of silver(I) ions was assessed to outline the possibilities of AgTNPs as a colorimetric probe for the fast and sensitive determination of bioflavonoids. It is shown that the interaction was accompanied by a bathochromic shift of the local surface plasmon resonance band of nanoparticles and an increase in its intensity. Seven bioflavonoids differing in their structure were tested. The influence of the structure of analytes and the main external factors on the analytical signal is discussed in detail. It was found that the detection limits of bioflavonoids in the selected optimal conditions increased in the series morin < rutin = quercetin < taxifolin and came to 0.9, 1.2, 1.2, and 2.0 μmol L-1, respectively. Chrysin, naringenin, and naringin were found not to affect the spectral characteristics of AgTNPs. The suggested approach was applied for the spectrophotometric determination of flavonoids in pharmaceuticals and onion peel.

Bioassay-Guided Fractionation of Siparuna glycycarpa&nbsp;n-Butanol Extract with Inhibitory Activity against Influenza A(H1N1)pdm09 Virus by Centrifugal Partition Chromatography (CPC)

Siparuna glycycarpa occurs in the Amazon region, and some species of this genus are used in Brazilian folk medicine. A recent study showed the inhibitory effect of this species against influenza A(H1N1)pdm09 virus, and in order to acquire active fractions, a polar solvent system n-butanol-methanol-water (9:1:10, v/v) was selected and used for bioassay-guided fractionation of n-butanol extract by centrifugal partition chromatography (CPC). The upper phase was used as stationary phase and the lower phase as mobile (descending mode). Among the collected fractions, the ones coded SGA, SGC, SGD, and SGO showed the highest antiviral inhibition levels (above 74%) at 100 µg·mL-1 after 24 h of infection. The bioactive fractions chemical profiles were investigated by LC-HRMS/MS data in positive and negative ionization modes exploring the Global Natural Products Social Molecular Networking (GNPS) platform to build a molecular network. Benzylisoquinoline alkaloids were annotated in the fractions coded SGA, SGC, and SGD collected during elution step. Aporphine alkaloids, O-glycosylated flavonoids, and dihydrochalcones in SGO were acquired with the change of mobile phase from lower aqueous to upper organic. Benzylisoquinolinic and aporphine alkaloids as well as glycosylated flavonoids were annotated in the most bioactive fractions suggesting this group of compounds as responsible for antiviral activity.

Comprehensive two-dimensional temperature-responsive × reversed phase liquid chromatography for the analysis of wine phenolics

Phenolic compounds are an interesting class of natural products because of their proposed contribution to health benefits of foods and beverages and as a bio-source of organic (aromatic) building blocks. Phenolic extracts from natural products are often highly complex and contain compounds covering a broad range in molecular properties. While many 1D-LC and mass spectrometric approaches have been proposed for the analysis of phenolics, this complexity inevitably leads to challenging identification and purification. New insights into the composition of phenolic extracts can be obtained through online comprehensive two-dimensional liquid chromatography (LC × LC) coupled to photodiode array and mass spectrometric detection. However, several practical hurdles must be overcome to achieve high peak capacities and to obtain robust methods with this technique. In many LC × LC configurations, refocusing of analytes at the head of the ²D column is hindered by the high eluotropic strength of the solvent transferred from the ¹D to the ²D, leading to peak breakthrough or broadening. LC × LC combinations whereby a purely aqueous mobile phase is used in the ¹D and RPLC is used in the ²D are unaffected by these phenomena, leading to more robust methods. In this contribution, the combination of temperature-responsive liquid chromatography (TRLC) with RPLC is used for the first time for the analysis of phenolic extracts of natural origin to illustrate the potential of this alternative combination for natural product analyses. The possibilities of the combination are investigated through analysis of wine extracts by TRLC × RPLC-DAD and TRLC × RPLC-ESI-MS.

Volatile Compounds from Flowers of Elaeagnus x submacrophylla Servett.: Extraction, Identification of Flavonoids, and Antioxidant Capacity

Beneficial to the ecosystem and with significant potential in permaculture, Elaeagnus x submacrophylla Servett. was studied here mainly for the identification of its floral odorants. After olfactory evaluation and determination of the volatile profile of freshly picked flowers by headspace/solid phase microextraction coupled with gas chromatography/mass spectrometry, an ethanolic extract was prepared and investigated for its antioxidant capacity. Unusual molecules were identified in the floral headspace, such as isochavicol or chrysanthemum acetate. The evaluation of the in vitro free radical scavenging capacity (from 0.4 to 1.3 mmol TE/g) and total phenolic content (65.1 mg GAE/g) of the extract pointed out a promising antioxidant activity, potentially related to the identification of several flavonoid glycosides. These results have to be considered in the context of the ever-increasing need to produce innovative natural extracts with notably interesting claims for the cosmetic field.

Full Collision Energy Ramp-MS2 Spectrum in Structural Analysis Relying on MS/MS

Albeit frequently being overlooked, MS² spectrum variation against collision energy (CE) implies auxiliary structural clues for m/z values. Online energy-resolved MS (ER-MS) provides the opportunity to acquire the trajectory of ion intensity against CE for any fragment ion of interest, thus exactly offering the desired momentum to empower the conventional MS² spectrum at a certain CE forward to a full-CE ramp MS² spectrum (FCER-MS²). Efforts were made here to construct an FCER-MS² spectrum and to evaluate its potential toward structural analysis. Flavonoids were employed as a proof of concept. MS² spectra of 76 compounds were recorded by LC-Q-Exactive-MS, and online ER-MS was subsequently programmed using LC-Qtrap-MS to build a breakdown graph for each obvious fragment ion. After defining the greatest value amongst all regressive apices as 100%, the normalized breakdown graphs comprised an FCER-MS² spectrum for each compound. The FCER-MS² spectrum contained the MS² spectrum at any CE as well as optimal CE (OCE) and maximal relative ion intensity (RII_max) of each fragment ion. Except the pronounced isomeric discrimination potential, either OCE or RII_max reflected certain structural properties, such as aglycone, glycosidic bond, and hydroxy, methoxy, and glycosyl substituents. These rules were subsequently applied for flavonoid-focused characterization of a famous herbal medicine, namely Scutellariae Radix, and high-level structural annotation was accomplished for 75 flavonoids. Above all, the FCER-MS² spectrum includes m/z, OCEs, and RII_max features, thus facilitating confidence-advanced structural analysis.

LC-Q-TOF-MS/MS detection of food flavonoids: principle, methodology, and applications

Flavonoids have been attracting increasing research interest because of their multiple health promoting effects. However, many flavonoids with similar structures are present in foods, often at low concentrations, which increases the difficulty of their separation and identification. Liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-Q-TOF-MS/MS) has become one of the most widely used techniques for flavonoid detection. LC-Q-TOF-MS/MS can achieve highly efficient separation by LC; it also provides structural information regarding flavonoids by Q-TOF-MS/MS. This review presents a comprehensive summary of the scientific principles and detailed methodologies (e.g., qualitative determination, quantitative determination, and data processing) of LC-Q-TOF-MS/MS specifically for food flavonoids. It also discusses the recent applications of LC-Q-TOF-MS/MS in determination of flavonoid types and contents in agricultural products, changes in their structures and contents during food processing, and metabolism in vivo after consumption. Moreover, it proposes necessary technological improvements and potential applications. This review would facilitate the scientific understanding of theory and technique of LC-Q-TOF-MS/MS for flavonoid detection, and promote its applications in food and health industry.

Supercritical fluid chromatography for the analysis of natural dyes: From carotenoids to flavonoids

Plant-derived natural dyes are used in a variety of formulated products, from food to cosmetics and pharmaceutics. In addition to their color, they also provide some bioactivity. While they are mostly analyzed with high-performance liquid chromatography, supercritical fluid chromatography was also employed for several dye families, mostly for carotenoids and chlorophylls, and more recently for anthraquinones and flavonoids. These supercritical fluid chromatography methods are described in this review. Because the dyes have different structures and structural variations (polarity, isomers, etc.), the best chromatographic system to achieve their separation is not always the same. Hydrophobic stationary phases are preferred for the most hydrophobic dyes (chlorophylls and carotenoids) while polar stationary phases are preferred for the polar dyes (anthraquinones and flavonoids). Regarding the mobile phase composition, chlorophylls and carotenoids are best eluted with moderate proportions of co-solvent in CO₂ (about 40%), while the most polar glycosylated flavonoids require higher proportions of co-solvent and acidic additives. Because dyes are colorful, ultraviolet-visible detection is often sufficient, while mass spectrometry offers additional structural information. Furthermore, fundamental information can also be gained through chromatographic analysis of dyes: either solubility in supercritical fluids, in view of their extraction, or retention behavior providing an understanding of stationary phase properties.

Prolonged Administration of Rudgea viburnoides (Cham.) Benth. Prevents Impairment of Redox Status, Renal Dysfunction, and Cardiovascular Damage in 2K1C-Hypertensive Rats by Inhibiting ACE Activity and NO-GMPC Pathway Activation

Rudgea viburnoides is widely found in the Brazilian Cerrado, and commonly used in Brazilian folk medicine. In this study, we evaluated the effects of prolonged administration of the aqueous extract from R. viburnoides leaves (AERV) on impaired redox status, renal dysfunction, and cardiovascular damage in 2K1C hypertensive rats, as well as its chemical composition by LC-DAD-MS. Renal hypertension (two kidney, one-clip model) was surgically induced in male Wistar rats and AERV (30, 100 and 300 mg/kg) was administered orally five weeks after surgery for 28 days. Renal function was assessed and urinary electrolytes, pH, and density were measured. Electrocardiography, blood pressure and heart rate were recorded. Cardiac and mesenteric vascular beds were isolated for cardiac morphometry and evaluation of vascular reactivity, and aortic rings were also isolated for measurement of cyclic guanosine monophosphate levels, and the redox status was assessed. Prolonged treatment with AERV preserved urine excretion and electrolyte levels (Na+, K+, Ca2+ and Cl-), reversed electrocardiographic changes, left ventricular hypertrophy and changes in vascular reactivity induced by hypertension, and reduced blood pressure and heart rate. This effect was associated with a positive modulation of tissue redox state, activation of the NO/cGMP pathway, and inhibition of the angiotensin-converting enzyme. Glycosylated iridoids, chlorogenic acids, glycosylated triterpenes, O-glycosylated flavonols, and triterpenoid saponins were annotated. AERV showed no acute toxicity in female Wistar rats. Therefore, AERV treatment reduced the progression of cardiorenal disease in 2K1C hypertensive rats, which can be involved with an important attenuation of oxidative stress, angiotensin-converting enzyme inhibition, and activation of the NO/cGMP pathway.

Flavonoids, alkaloids and saponins: are these plant-derived compounds an alternative to the treatment of rheumatoid arthritis? A literature review

Rheumatoid arthritis (RA) is a systemic inflammatory disease characterized by synovial inflammation leading to progressive joint erosion and, eventually, joint deformities. RA treatment includes anti-inflammatories, corticosteroids, synthetic disease-modifying antirheumatic drugs (DMARDs), and immunosuppressants. Drug administration is associated with adverse reactions, as gastrointestinal ulcers, cardiovascular complications, and opportunistic infections. Wherefore, different plant-derived phytochemical compounds are studied like new therapeutic approach to treatment of RA. Among the phytochemical compounds of plants for treatment of RA, flavonoids, alkaloids and saponins are related for present anti-inflammatory activity and act as physiological and metabolic regulators. They have low toxicity compared to other active plant compounds, so their therapeutic properties are widely studied. The intention of the review is to present an overview of the therapeutics of flavonoids, alkaloids, and saponins for RA. An extensive literature survey was undertaken through different online platforms:

PubMed, SciELO, and Virtual Health Library databases, to identify phytochemical compounds used in RA treatment and the descriptors used were medicinal plants, herbal medicines, and rheumatoid arthritis. Seventy-five research and review articles were found to be apt for inclusion into the review. The present study summarizes the phytochemicals isolated from plants that have therapeutic effects on RA models, in vitro and in vivo. The studied substances exerted anti-inflammatory, chondroprotective, immunoregulatory, anti-angiogenic, and antioxidant activities and the most compounds possess good therapeutic properties, valuable for further research for treatment of RA.

Changes of bioactive components and antioxidant potential during fruit development of Prunus humilis Bunge

Dynamic changes in flavonoid, total phenol, and antioxidant potential in different Prunus humilis accessions during fruit development stages were studied in order to provide a reference for the optimum harvest time for flavonoid extraction. 'Nongda 4', 'Nongda 5', 'DS-1' and '02-16' were selected as plant materials to determine the content of flavonoid, total phenol and antioxidant indices during six fruit development stages. Changes in total flavonoid content (TFC) and total phenol content (TPC) in different accessions of P. humilis were slightly different depending on the development stage of P. humilis fruit. TFC and TPC in 'Nongda 5' fruit showed a trend of continuous decline. There was a small increase in TFC and TPC from the young fruit stage to the stone hardening stage, followed by a decreasing trend, and then to the lowest level at the ripening stage of 'Nongda 4', 'DS-1', and '02-16' fruits. The trend of antioxidant capacity (ABTS, FRAP, DPPH) with the TFC and TPC of P. humilis fruit was basically the same, and the correlation analysis results showed that the TFC of P. humilis fruit was positively correlated with the antioxidant indices (P<0.01). Catechin (CC), rutin (RT), and quercetin-7-O-β-D-glucopyranoside (Q7G) were detected in all the fruit development stages of the four P. humilis fruits. Among them, catechin was the most abundant component, accounting for approximately 10%. Myricetin (MC) and quercetin (QC) were generally detected only in the early fruit development stage, but not in the later fruit development stage. Correlation analysis showed that the flavonoid components with TFC, TPC, and antioxidant indices differed between the different accessions. RT, CC, and liquiritigenin (LR) had a stronger correlation with TFC and antioxidant indices. Cyanidin-3-O-glucoside (C3G) was not detected until the coloring stage in two red P. humilis accessions ('Nongda 4' and 'DS-1'), and so it is better to choose a red P. humilis fruit to extract C3G at the ripening stage. Selecting an early stage of fruit development, especially the stone hardening stage, was important for extracting flavonoids, total phenols and other components. We believe that our results will provide basic information and reference for evaluation of fruit nutrition and health benefits, breeding of functional new varieties, and efficient utilization of P. humilis fruit.

Exploring the role of polyphenols in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory and autoimmune disorder which is mainly characterized by inflammation in joints, bone erosions and cartilaginous destruction that leads to joint dysfunction, deformation, and/or permanent functional impairment. The prevalence of RA is increasing, incurring a considerable burden on healthcare systems globally. The exact etiology of RA is unknown, with various pathways implicated in its pathophysiology. Non-steroidal anti-inflammatory drugs (NSAIDs) including celecoxib, diclofenac and ibuprofen, disease-modifying anti-rheumatic drugs (DMARD) including azathioprine, methotrexate and cyclosporine, biological agents including anakinra, infliximab, and rituximab and immunosuppressants are used for symptomatic relief in patients with RA, but these medications have severe adverse effects such as gastric ulcers, hypertension, hepatotoxicity and renal abnormalities which restrict their use in the treatment of RA; new RA treatments with minimal side-effects are urgently required. There is accumulating evidence that dietary polyphenols may show therapeutic efficacy in RA through their antioxidant, anti-inflammatory, apoptotic, and immunosuppressant activities and modulation of the tumor necrosis factor-α (TNF-α), interleukin (IL)-6, mitogen-activated protein kinase (MAPK), IL-1β, c-Jun N-terminal kinase (JNK), and nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways. While resveratrol, genistein, carnosol, epigallocatechin gallate, curcumin, kaempferol, and hydroxytyrosol have also been studied for the treatment of RA, the majority of data are derived from animal models. Here, we review the various pathways involved in the development of RA and the preclinical and clinical data supporting polyphenols as potential therapeutic agents in RA patients. Our review highlights that high-quality clinical studies are required to decisively establish the anti-rheumatic efficacy of polyphenolic compounds.

Electrospray ionisation mass spectrometric behaviour of flavonoid 5-O-glucosides and their positional isomers detected in the extracts from the bark of Prunus cerasus L. and Prunus avium L

INTRODUCTION

Literature data concerning the electrospray ionisation mass spectrometry (ESI-MS) behaviour of flavonoid 5-O-glycosides are poor and sometimes disputable. Therefore, we decided to analyse the compounds of this kind present in the bark of Prunus cerasus and Prunus avium by using high-performance liquid chromatography HPLC/ESI-MS.

OBJECTIVE

The aim of this study is to obtain the comprehensive information about the ESI-MS(+/-) behaviour of flavonoid 5-O-glucosides, to compare their behaviour with that of their positional isomers, to confirm that the known susceptibility of flavonoid 5-O-glucosides to hydrolysis may be successfully used for their identification.

METHOD

The bark from Prunus trees was extracted with pure methanol or, in order to perform hydrolysis and extraction simultaneously, with 5% methanolic solution of hydrochloric acid. The HPLC-ESI-MS analyses were performed using a Waters model 2690 HPLC pump and Waters/Micromass ZQ2000 mass spectrometer.

RESULTS

Flavonoid 5-O-glycosides were completely hydrolysed under the acid conditions used, in contrast to their positional isomers. In positive ion mode, at low cone voltage, flavonoid 5-O-glycosides yield abundant Y₀ ⁺ aglycone ions, in contrast to their positional isomers. In the negative ion mode, flavonoid 5-O-glycosides do not yield [Y₀ - H]^-· fragment ions, in contrast to their positional isomers. When aglycone contains only two hydroxyl groups, the flavonoid 5-O-glycosides can be detected in negative ion mode, whereas their positional isomers do not yield [M - H]^- ions.

CONCLUSION

It has been demonstrated that the susceptibility to hydrolysis of the analysed compounds, the abundances of respective fragment ions formed, and their ESI(-) response allow unambiguous identification of flavonoid 5-O-glycosides and their differentiation from their positional isomers.

Comprehensive off-line CCC × LC-DAD-MS separation of Cyclopia pubescens Eckl. & Zeyh. phenolic compounds and structural elucidation of isolated compounds

INTRODUCTION

The minor phenolic constituents of Cyclopia pubescens Eckl. & Zeyh. are unknown and one dimensional (1D) liquid chromatography (LC) is unable to provide sufficient separation.

METHODOLOGY

A two-dimensional (2D) LC method incorporating normal-phasehigh performance countercurrent chromatography (NP-HPCCC) in the first dimension (¹ D) and reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) as the second dimension (² D) was developed. The analytical HPCCC method was subsequently scaled up to semi-preparative mode and fractions pooled based on phenolic sub-groups. The phenolic compounds in selected fractions were subsequently isolated using RP-HPLC on a C₁₈ column. Isolated compounds were identified by nuclear magnetic resonance (NMR) spectroscopy. The absolute configurations of compounds were determined by optical rotation and electronic circular dichroism spectra. Sugars were identified by gas chromatography-mass spectrometry (GC-MS) analysis.

RESULTS

The comprehensive off-line 2D CCC × LC method gave a good spread of the phenolic compounds. Orthogonality calculated using both the convex hull and conditional entropy methods were 81%. High-resolution mass spectrometric fragmentation spectra obtained from a quadrupole-time-of-flight instrument and ultraviolet-visible (UV-vis) spectral data were used to (tentatively) identify 32 phenolic compounds from the analytical CCC fractions. Of the seven isolated compounds, (2S)-5-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl]eriodictyol (3) and (2S)-5-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl]-5,7,3',4'-tetrahydroxyflavan (4) were newly identified in all plants. The other isolated compounds were identified as (2S)-5-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl]naringenin (1), R-neo-eriocitrin (2), 3-O-α-l-arabinopyranosyl-3,4-dihydroxybenzoic acid (5), 4-O-β-d-glucopyranosyl-Z-4-hydroxycinnamic acid (6) and 4-(4'-O-β-d-glucopyranosyl-4'-hydroxy-3'-methoxyphenyl)-2-butanone (7).

CONCLUSIONS

Among the 32 compounds (tentatively) identified, only six were previously identified in Cyclopia pubescens using 1D LC. Most of the isolated compounds were also identified for the first time in Cyclopia spp., improving the knowledge of the minor phenolic compounds of this genus.

Enzymatic Synthesis, Structural Analysis, and Evaluation of Antibacterial Activity and α-Glucosidase Inhibition of Hesperidin Glycosides

This study was designed to investigate the structure of synthesized hesperidin glycosides (HGs) and evaluate their antibacterial and α-glucosidase inhibitory activities. The preliminary structure of HGs was confirmed by glucoamylase treatment and analyzed on thin layer chromatography (TLC). The LC-MS/MS profiles of HGs showed the important fragments at m/z ratios of 345.21 (added glucose to glucose of rutinose in HG1) and 687.28 (added maltose to glucose of rutinose in HG2), confirming that the structures of HG1 and HG2 were α-glucosyl hesperidin and α-maltosyl hesperidin, respectively. In addition, 1H and 13C-NMR of hesperidin derivatives were performed to identify their α-1,4-glycosidic bonds. The MIC and MBC studies showed that transglycosylated HG1 and HG2 had better antibacterial and bactericidal activities than hesperidin and diosmin, and were more active against Staphylococcus aureus than Escherichia coli. Hesperidin, HG1, HG2, and diosmin inhibited α-glucosidase with IC50 values of 2.75 ± 1.57, 2.48 ± 1.61, 2.36 ± 1.48, and 2.99 ± 1.23 mg/mL, respectively. The inhibition kinetics of HG2 shown by a Lineweaver–Burk plot confirmed HG2 was an α-glucosidase competitive inhibitor with an inhibitor constant, Ki, of 2.20 ± 0.10 mM. Thus, HGs have the potential to be developed into antibacterial drugs and treatments for treating α-glucosidase-associated type 2 diabetes.

Cost-Effective Simultaneous Separation and Quantification of Phenolics in Green and Processed Tea Using HPLC–UV–ESI Single-Quadrupole MS Detector and Python Script

Phenolic composition of green tea (Camellia sinensis) varies according to manufacturing processes that result in deglycosylation of glycosylated phenolics and condensation, epimerization, and degalloylation of flavan-3-ols (catechins). Ambiguous phenolic assignments based on UV absorbance alone can occur when the chromatographic peaks overlapped slightly. We established an improved method using an HPLC–UV coupled with a single-quadrupole MS detector (MS1) that can reject false UV peaks after checking the preceding MS1 peaks. Adjusted UV data coded by the Python algorithm were deployed to compare tea phenolics. Performance validation of the MS1 and UV analysis methods for 19 phenolics revealed a sensitivity of 0.17 and 0.47 pmol/injection, limit of detection of 15 and 33 μg/L, limit of quantification of 50 and 110 μg/L, intra-day precision of 5% and 1% relative standard deviation, and trueness of 83–135% and 97–100%, respectively. Our results suggest that the HPLC–UV–MS1 method, which is a low operational cost method, potentially provides the precise phenolic composition of teas.

Analytical determinations of luteolin

Plants, through the photosynthesis process, produce the substances necessary for all the life cycles of nature, which are called "primary metabolites." Moreover, there are some plants that synthesize, in addition to these, other substances with more specific functions, which are known as "secondary metabolites." It is inside this group that flavonoids are located, whose main function is to protect organisms from damage caused by different oxidizing agents. Luteolin (3,4,5,7-tetrahydroxy-flavone) belongs to the sub-class of flavonoids known as flavones and is one of 10,000 flavonoids currently known, being one of the most bio-active flavonoids. Its various beneficial properties for health, together with the increasing reduction in the use of synthetic antioxidants, make the study of luteolin a very active field. Within this, the quantification of this molecule has become a subject of very special interest given that it is transversal to all fields. In this review article, we aim to give the reader a broad and deep vision of this topic, focusing on the events reported in the last 5 years and covering all possible techniques related to analytical determinations. We will discuss in terms of advantages and disadvantages between techniques, selectivity, sensitivity, costs, time consumption, and reagents as well as in the complexity of operations.

Nephroprotective and antilithiatic activities of Costus spicatus (Jacq.) Sw.: Ethnopharmacological investigation of a species from the Dourados region, Mato Grosso do Sul State, Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Costus spicatus (Jacq.) Sw., also known as "cana-do-brejo," is a species that is widely used in Brazilian traditional medicine for the treatment of kidney diseases. However, no studies have evaluated its nephroprotective and antilithiatic effects.

AIM

To investigate nephroprotective and antilithiatic effects of C. spicatus in a preclinical model of acute kidney injury (AKI) and in vitro nephrolithiasis.

MATERIALS AND METHODS

C. spicatus leaves were collected directly from the natural environment in the Dourados region, Mato Grosso do Sul State, Brazil. The ethanol-soluble fraction of C. spicatus (ESCS) was obtained by infusion. Phytochemical characterization was performed by liquid chromatography coupled to diode array detector and mass spectrometer (LC-DAD-MS). We assessed whether ESCS has acute or prolonged diuretic activity. The nephroprotective effects of ESCS were evaluated in a model of AKI that was induced by glycerol (10 ml/kg, intramuscularly) in Wistar rats. Different doses of ESCS (30, 100, and 300 mg/kg) were administered orally for 5 days before the induction of AKI. Urinary parameters were measured on days 1, 3, 5, and 7. Twenty-four hours after the last urine collection, blood samples were obtained for the biochemical analysis. Blood pressure levels, renal vascular reactivity, renal tissue redox status, and histopathological changes were measured. Antilithiatic effects were evaluated by in vitro crystallization. Calcium oxalate precipitation was induced by sodium oxalate in urine samples with ESCS at 0.05, 0.5, and 5 mg/ml.

RESULTS

From LC-DAD-MS analyses, flavonoids, saponins and other phenolic compounds were determined in the composition of ESCS. Significant reductions of the excretion of urinary total protein, creatinine, sodium, and potassium were observed in the AKI group, with significant histopathological damage (swelling, vacuolization, necrosis, and inflammatory infiltration) in the proximal convoluted tubule. Treatment with ESCS exerted a significant nephroprotective effect by increasing the urinary excretion of total protein, urea, creatinine, sodium, potassium, calcium, and chloride. All of the groups that were treated with ESCS exhibited a reduction of histopathological lesions and significant modulation of the tissue redox state. We also observed a concentration-dependent effect of ESCS on the crystallization of urinary crystals, with reductions of the size and proportion of monohydrated crystals.

CONCLUSION

The data suggest that C. spicatus has nephroprotective and antilithiatic effects, suggesting possible effectiveness in its traditional use.

Recent applications of ion mobility spectrometry in natural product research

Ion mobility spectrometry (IMS) is a rapid separation technique capable of extracting complementary structural information to chromatography and mass spectrometry (MS). IMS, especially in combination with MS, has experienced inordinate growth in recent years as an analytical technique, and elicited intense interest in many research fields. In natural product analysis, IMS shows promise as an additional tool to enhance the performance of analytical methods used to identify promising drug candidates. Potential benefits of the incorporation of IMS into analytical workflows currently used in natural product analysis include the discrimination of structurally similar secondary metabolites, improving the quality of mass spectral data, and the use of mobility-derived collision cross-section (CCS) values as an additional identification criterion in targeted and untargeted analyses. This review aims to provide an overview of the application of IMS to natural product analysis over the last six years. Instrumental aspects and the fundamental background of IMS will be briefly covered, and recent applications of the technique for natural product analysis will be discussed to demonstrate the utility of the technique in this field.

From untargeted metabolomics to the multiple reaction monitoring-based quantification of polyphenols in chocolates from different geographical areas

Plants, including cocoa bean, are the main source of metabolites with multiple biological functions. Polyphenol extracts are widely used as a nutraceutical supplement for their well-known health-promoting role. In this paper, a preliminary untargeted metabolic screening was carried out by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF)/TOF on a pool of chocolate samples made by cocoa beans of different geographical areas. Then, a targeted approach was developed for polyphenol quantification by an optimized Liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method multiple reaction monitoring (MRM) ion mode. Detection limit of polyphenol standard ranged between 1 and 25 pg/μl with variation coefficient lower than 15%. External calibration curves were used for quantification of polyphenols in 18 samples. Fifty polyphenols were detected in a single LC-MRM/MS run and quantified by monitoring almost 90 transitions in a 5-minute run. The polyphenols content of different cocoa beans from several countries was finally compared by principal component analysis (PCA) statistical analysis suggesting that the chocolate made by Ecuador cocoa beans showed the highest level of polyphenols.

Identity confirmation of anthocyanins in berries by LC-DAD-IM-QTOFMS

Rugged analytical methods for the screening and identity confirmation of anthocyanins require a dedicated sample preparation, chromatographic setup, and the reliable generation of multiple identification points to confirm identity against the wide range of phenolic compounds typically present in food, beverage, and plant material samples. To this end, combinations of spectroscopic and mass spectrometric detection are frequently employed for this application to provide higher confidence in the absence of authentic standards. In the present work, low‐field drift tube ion mobility (DTIM) separation is evaluated for this task using a LC–DAD–DTIM–QTOFMS method. DTIM‐MS allows accurate determination of collision cross sections (^DTCCS) for all analysed compounds as well as a precise alignment tool for reconciling fragment and precursor ions in data independent acquisition mode. The presented approach thereby allows for an anthocyanin screening method taking true advantage of all dimensions of the analytical platform: relative retention (RPLC), UV/VIS absorption spectrum, accurate mass, ^DTCCS_N2, and confirmed high‐resolution fragment ions. From the analysis of authentic standards and several berry samples primarily from the Vaccinium genus, Level 1 confirmation data for six anthocyanins from the cyanidin family, and Level 2 confirmation for a further 29 anthocyanins confirmed in berry samples is provided. The method and accompanying dataset provided as part of this work provides a means to develop anthocyanin screening methods using the ion mobility dimension as an additional alignment and filtering parameter in data independent analysis acquisition across any LC–IM–MS platform.