Ultra-high Performance Liquid Chromatography-diode Array Research Articles

Protective Potential of Cicerbita alpina Leaf Extract on Metabolic Disorders and Oxidative Stress in Model Animals.

Metabolic disorders (MDs) include disease states such as diabetes mellitus, obesity, dyslipidemia, hyperuricemia, etc., affecting about 30% of the planet's population. The purpose of the present study was to investigate the protective potential of Cicerbita alpina leaf extract (ECA) against chemically induced type 2 diabetes in Wistar rats. Additionally, some biochemical parameters in the blood serum and liver, as well as histopathological investigation, were also performed. Quantitative analysis of the major compounds in the used extract was performed using ultrahigh-performance liquid chromatography-diode array detection (UHPLC-DAD) analyses using the external standard method. C. alpina extract revealed a beneficial effect on MDs, lowering blood sugar levels and MDA quantity in the liver, increasing the reduced glutathione level, and increasing antioxidant enzyme activity. Cichoric acid (CA) (91.93 mg/g dry extract (de) ± 4.64 mg/g de) was found to be the dominant compound in the extract, followed by caftaric (11.36 ± 2.10 mg/g de), and chlorogenic acid (CGA) (9.25 ± 0.05 mg/g de). In conclusion, C. alpina leaf extract (ECA) is rich in caffeoyltartaric and caffeoylquinic acids and provides beneficial effects on the diabetic animal model.

Bioactive (Poly)phenol Concentrations in Plant-Based Milk Alternatives in the US Market.

Plant-based milk alternatives (PBMAs) are increasingly consumed as a dairy alternative [Olson, S. Milk and Non-Dairy Milk - US - 2021, 2021.]. Plant foods are rich sources of (poly)phenols, but concentrations of these bioactive phytochemicals in processed PBMAs are not well documented. We procured twenty-seven PBMA products of 6 types (almond, coconut, oat, pea, rice, and soy) for (poly)phenol analysis. Samples were analyzed via ultra high-performance liquid chromatography-diode array with mass spectrometry. The (poly)phenol content of PBMAs varies and is dependent on plant source, brand, and added flavorings. Soy milk had the highest concentration and rice milk had the lowest (91.9 ± 2.7 and 0.9 ± 0.2 mean mg ± SD/cup serving, respectively). Almond milk, the most widely consumed PBMA, averaged 12.1 ± 8.2 mg/cup serving, but the majority of (poly)phenols are derived from added flavorings. PBMAs contain a wide range of potentially bioactive (poly)phenols and may contribute significantly to overall dietary (poly)phenol intake with the potential to impact health outcomes.

Comparative study of atmospheric brown carbon at Shanghai and the East China Sea: Molecular characterization and optical properties

The pollution burdens and compositions of atmospheric brown carbon (BrC) that determine their impacts on climate-health-ecosystems have not been well studied, particularly in some mega-economic coastal areas. Herein, atmospheric BrC samples synchronously collected from urban Shanghai (SH) and Huaniao Island (HNI) in the East China Sea during winter were characterized through ultrahigh-performance liquid chromatography-diode array detector-high resolution mass spectrometry (UHPLC-DAD-HRMS). The three polarity-dependent BrC fractions exhibited significant differences in both light absorption and chromophore composition. The average light absorption coefficients of BrC subfractions at 365 nm in SH were 2.6–3.7 times higher than those in HNI. The water-insoluble BrC (WIS-BrC) and humic-likes BrC (HULIS-BrC) dominated the total BrC absorption in SH (45 ± 7 %) and HNI (43 ± 6 %), respectively. Compared with SH, the higher O/Cw, lower molecule conjugation degree, and reduced mass absorption efficiency at 365 nm (MAE365) in HNI imply a potential bleaching mechanism during the transportation oxidation process. Thousands of BrC chromophores were detected at both sites. >20 major chromophores with strong absorption were unambiguously identified in HULIS-BrC and accounted for ∼40 % of the HULIS light absorption at 365 nm at both sites. These chromophores in SH HULIS-BrC featured oxygenated aromatics and nitroaromatics, while alkyl benzenesulfonic acids with emissions from cargo ships were found in HNI HULIS-BrC. Moreover, 22 major chromophores identified in WIS-BrC included alkaloids, polyaromatic hydrocarbons (PAHs), and carbonyl oxygenated PAHs, contributing 39 % and 49 % of the WIS-BrC light absorption at 365 nm in SH and HNI, respectively. Ascertaining the molecular-specific optical properties of BrC chromophores over the mega-economic coastal area is helpful for the predictive understanding of the sources and evolution of BrC, as well as its atmospheric behavior from land to sea.

Resolving Ultraviolet-Visible Spectra for Complex Dissolved Mixtures of Multitudinous Organic Matters in Aerosols.

Light-absorbing organic aerosols, referred to as brown carbon (BrC), play a vital role in the global climate and air quality. Due to the complexity of BrC chromophores, the identified absorbing substances in the ambient atmosphere are very limited. However, without comprehensive knowledge of the complex absorbing compounds in BrC, our understanding of its sources, formation, and evolution mechanisms remains superficial, leading to great uncertainty in climatic and atmospheric models. To address this gap, we developed a constrained non-negative matrix factorization (NMF) model to resolve the individual ultraviolet-visible spectrum for each substance in dissolved organic aerosols, with the power of ultrahigh-performance liquid chromatography-diode array detector-ultrahigh-resolution mass spectrometry (UHPLC-DAD-UHRMS). The resolved spectra were validated by selected standard substances and validation samples. Approximately 40,000 light-absorbing substances were recognized at the MS1 level. It turns out that BrC is composed of a vast number of substances rather than a few prominent chromophores in the urban atmosphere. Previous understanding of the absorbing feature of BrC based on a few identified compounds could be biased. Weak-absorbing substances missed previously play an important role in BrC absorption when they are integrated due to their overwhelming number. This model brings the property exploration of complex dissolved organic mixtures to a molecular level, laying a foundation for identifying potentially significant compositions and obtaining a comprehensive chemical picture.

Quantitative determination of specialised metabolites in different parts of Juglans regia Linn. and Carya illinoinensis (Wangenh.) K. Koch by using UHPLC-DAD-QTOF-MS/MS.

Juglans regia Linn. and Carya illinoinensis (Wangenh.) K. Koch are nut-producing plant species of the Juglandaceae family. Bioactive compounds like naphthoquinones, tetralones, and diarylheptanoids are dominant in these species. The study aimed to develop and validate a fast and sensitive analytical method by ultrahigh-performance liquid chromatography diode array detection mass spectrometry (UHPLC-DAD-MS) for quantification and identification of bioactive compounds in fruit pericarps and leaves of J.regia and C.illinoinensis collected from two different states of north India. The dried pericarps of J.regia and C.illinoinensis (500 mg) were extracted with ethyl acetate-methanol (50:50 v/v, 20 mL, 50°C, 30 min) by ultrasonication and analysed by ultrahigh-performance liquid chromatography diode array detection quadrupole time-of-flight tandem mass spectrometry (UHPLC-DAD-QTOF-MS/MS) for qualitative and quantitative examination of phytoconstituents. The method was validated according to International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human use (ICH) guidelines for linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ). Here, we report the quantification of dihydrophaseic acid (1), 4,5-dihydroxytetralone (2), 4,8-dihydroxytetralone (3), 5,8-dihydroxy-3-methoxytetralone (4), and juglanin A (5) in the pericarps and leaves of J.regia and C.illinoinensis. Furthermore, using the hyphenated analytical method, a total of 62 compounds were tentatively characterised in different samples. The principal component analysis (PCA) showed diversity between the analysed sample's composition. Also, the study evaluated the variation of bioactive compounds among different parts of J.regia and C.illinoinensis collected from different regions of northern India by UHPLC-DAD-QTOF-MS/MS. The developed method is simple, rapid, and selective for the identification and characterisation of bioactive molecules.

Sterilisation of biopharmaceuticals: Effect of gamma irradiation, e-beam irradiation and nitrogen dioxide on human insulin

Biopharmaceuticals are administered parenterally and therefore sterility is required. Sterility can be obtained via different processes including exposure to steam or dry heat. Sterilisation studies on biopharmaceuticals, which are highly sensitive medicinal products, are scarce. This study investigates the effect of different sterilisation processes on recombinant human insulin in solid state (gamma and e-beam irradiation (w/wo dry ice), nitrogen dioxide (NO2)) and in aqueous solution (gamma irradiation (w/wo dry ice, w/wo glycerin)) using ultra-high performance liquid chromatography-diode array detection-mass spectrometry. It is observed that NO2 substantially degrades the solid samples, while gamma and e-beam irradiation result in lower levels of degradation (mean normalized peak areas of 95.2–96.2 % with respect to the non-sterilised samples). Gamma irradiation of insulin solutions with and without dry ice at 2.5 kGy results in mean normalised peak areas of 85 % and <40 % with respect to the non-sterilised samples, respectively. It is concluded that sterilisation using ionising radiation of liquid biopharmaceuticals with insulin and sterilisation of insulin dry powder using NO2 is less suitable with the set-ups used here because of substantial degradation. In contrast, evidence is presented in favour of sterilisation of insulin dry powder using ionising radiation.

Development of a Novel Flavored Goat Cheese with Gentiana lutea Rhizomes.

Gentiana lutea rhizomes, generally used as a bittering agent in food, were harvested from two geographical sites (Massif Central: MC and Jura: J) to evaluate their potential use in the flavoring step during goat cheesemaking. Gentian flavored goat cheeses (MCGC and JGC) were elaborated by a one-night immersion of unflavored goat cheeses (CGC) into gentian-infused whey. The impregnation of gentian in goat cheeses was evaluated by chemical and sensory analysis. The chemical composition of cheeses was analyzed by HS-SPME-GC-MS (Head-Space-Solid Phase MicroExtraction-Gas Chromatography-Mass Spectrometry) for volatile compounds (alcohols, ketones, aldehydes, esters, alkenes, alkanes, acids, terpenes) and UHPLC-DAD (Ultra High-Performance Liquid Chromatography-Diode Array Detector) for gentian bitter compounds (seco-iridoids). The sensory analysis consisted of a bitterness rating and a free description of cheeses by 17 trained panelists. Results of the study highlighted that unflavored goat cheeses presented higher unpleasant notes (goaty and lactic whey) and higher amounts of hexanoic acid and toluene compared to gentian flavored goat cheeses. The bitterness of gentian flavored goat cheeses was higher compared to unflavored cheeses and could be explained by loganic acid transfer from yellow gentian to flavored cheeses. Other free descriptors of gentian flavored goat cheeses revealed more complex notes (herbal, vegetal, floral, sweet, spicy and creamy) and higher relative amounts of volatile compounds such as 3-methyl butanoic acid, 2-methyl propanoic acid, 4-methyl decane, 2,3-butanediol, ethanol, diacetyl, methyl acetate and 2-phenylethyl acetate, compared to unflavored cheeses. Phenylethyl acetate was the only volatile compound that enabled differentiation of gentian origin on gentian flavored goat cheeses. Gentian rhizomes could be considered a promising flavoring agent contributing to the olfactive and gustative complexity of flavored goat cheeses and the reduction of their goaty perceptions.

Development and optimization of natural deep eutectic solvent-based dispersive liquid-liquid microextraction coupled with UPLC-UV for simultaneous determination of parabens in personal care products: evaluation of the eco-friendliness level of the developed method.

Dispersive liquid-liquid microextraction (DLLME) combined with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD) method has been developed and validated for the determination of parabens in personal care products. In this study, a natural deep eutectic solvent (NADES) composed of menthol and formic acid at a molar ratio of 1 : 2 was prepared and used as an extraction solvent. The influencing variables on the extraction efficiency such as extraction solvent type and volume, composition of NADES, salt addition, vortex and centrifugation time were investigated. The proposed method exhibited good linearity with determination coefficients of ≥0.9992. The relative recoveries for the studied analytes ranged from 82.19 to 102.45%. Limits of detection and limits of quantification were in the range of 0.17-0.33 ng mL-1 and 0.51-0.99 ng mL-1, respectively. To evaluate the applicability of the developed method, it was successfully applied to determine four parabens in personal care products. Additionally, the eco-friendliness level of the presented method was evaluated using Eco-Scale Assessment, Green Analytical Procedure Index and Analytical GREEnness metric. The developed method is simple, environmentally friendly and cost effective and it could be employed for determination of parabens in personal care products without harming the environment.

GC-MS and LC-DAD-MS Phytochemical Profiling for Characterization of Three Native Salvia Taxa from Eastern Mediterranean with Antiglycation Properties.

Salvia fruticosa and S. pomifera subsp. calycina are native to Eastern Mediterranean and S. pomifera subsp. pomifera is endemic to Greece. The primary aim of this study was to develop an analytical methodology for metabolomic profiling and to study their efficacy in combating glycation, the major biochemical complication of diabetes. After sequential ultrasound-assisted extraction of 2 g of leaves with petroleum ether and 70% methanol, the volatile metabolites in the petroleum ether extracts were studied with GC-MS (Gas Chromatography-Mass Spectrometry), whereas the polar metabolites in the hydroalcoholic extracts were determined and quantified by UHPLC-DAD-ESI-MS (Ultra-High Performance Liquid Chromatography-Diode Array Detector-Mass Spectrometry). This methodology was applied to five populations belonging to the three native taxa. 1,8-Cineole was the predominant volatile (34.8-39.0%) in S. fruticosa, while S. pomifera had a greater content of α-thujone (19.7-41.0%) and β-thujone (6.0-39.1%). Principal Component Analysis (PCA) analysis of the volatiles could discriminate the different taxa. UHPLC-DAD-ESI-MS demonstrated the presence of 50 compounds, twenty of which were quantified. PCA revealed that not only the taxa but also the populations of S. pomifera subsp. pomifera could be differentiated. All Salvia samples inhibited advanced glycation end-product formation in a bovine serum albumin/2-deoxyribose assay; rosmarinic and carnosic acid shared this activity. This study demonstrates the antiglycation activity of S. fruticosa and S. pomifera extracts for the first time and presents a miniaturized methodology for their metabolomic profiling, which could aid chemotaxonomic studies and serve as a tool for their authentication and quality control.

PhUGT78A22, a novel glycosyltransferase in Paeonia ‘He Xie’, can catalyze the transfer of glucose to glucosylated anthocyanins during petal blotch formation

BackgroundFlower color patterns play an important role in the evolution and subsequent diversification of flowers by attracting animal pollinators. This interaction can drive the diversity observed in angiosperms today in many plant families such as Liliaceae, Paeoniaceae, and Orchidaceae, and increased their ornamental values. However, the molecular mechanism underlying the differential distribution of anthocyanins within petals remains unclear in Paeonia.ResultsIn this study, we used an intersectional hybrid between the section Moutan and Paeonia, hereafter named Paeonia ‘He Xie’, which has purple flowers with dark purple blotches. After Ultra-high performance liquid chromatography-diode array detector (UPLC-DAD) analysis of blotched and non-blotched parts of petals, we found the anthocyanin content in the blotched part was always higher than that in the non-blotched part. Four kinds of anthocyanins, namely cyanidin-3-O-glucoside (Cy3G), cyanidin-3,5-O-glucoside (Cy3G5G), peonidin-3-O-glucoside (Pn3G), and peonidin-3,5-O-glucoside (Pn3G5G) were detected in the blotched parts, while only Cy3G5G and Pn3G5G were detected in the non-blotched parts. This suggests that glucosyltransferases may play a vital role in the four kinds of glucosylated anthocyanins in the blotched parts. Moreover, 2433 differentially expressed genes (DEGs) were obtained from transcriptome analysis of blotched and non-blotched parts, and a key UDP-glycosyltransferase named PhUGT78A22 was identified, which could use Cy3G and Pn3G as substrates to produce Cy3G5G and Pn3G5G, respectively, in vitro. Furthermore, silencing of PhUGT78A22 reduced the content of anthocyanidin 3,5-O-diglucoside in P. ‘He Xie’.ConclusionsA UDP-glycosyltransferase, PhUGT78A22, was identified in P. ‘He Xie’, and the molecular mechanism underlying differential distribution of anthocyanins within petals was elucidated. This study provides new insights on the biosynthesis of different kinds of anthocyanins within colorful petals, and helps to explain petal blotch formation, which will facilitate the cultivar breeding with respect to increasing ornamental value. Additionally, it provides a reference for understanding the molecular mechanisms responsible for precise regulation of anthocyanin biosynthesis and distribution patterns.

Detoxification mechanism of vinegar-processed Kansui revealed by systematic phytochemical analysis using ultrahigh-performance liquid chromatography diode array detection tandem mass spectrometry, ultrahigh-performance liquid chromatography high-resolution mass spectrometry and in silico drug target identification.

The dried roots of Euphorbia kansui L., known as Kansui, are used to treat ascites and edema in traditional Chinese medicine. However, the toxicity of this herb has seriously restricted its clinical application. A unique vinegar-processing method has been used to reduce its toxicity since the time of ancient China. However, the detoxification mechanism underlying such vinegar processing has not been fully revealed. To find the answer, the process-induced changes in components should be carefully investigated. We performed a systematic analysis of chemical components in raw and vinegar-processed Kansui using ultrahigh-performance liquid chromatography (UHPLC) diode array detection tandem mass spectrometry and UHPLC high-resolution mass spectrometry. Thirty-one chemical components in raw and vinegar-processed Kansui were found, the chemical structures of 28 components among them were proposed and the process-induced changes in components were then investigated. A comprehensive conclusion about the process-induced chemical change was drawn. It was found that jatrophane-type diterpenoids decreased markedly after vinegar processing, while ingenane-type diterpenoids were retained during vinegar processing. In silico drug target identification gave hints that jatrophane-type diterpenoids, which decreased markedly during vinegar processing, may have more intense toxicity involving cholinesterase and mitogen-activated protein kinases, while ingenane-type diterpenoids, which were retained during vinegar processing, may have a more intense therapeutic effect involving carbonic anhydrase. The possible detoxification mechanism of vinegar-processed Kansui is presented. The research has significance for the therapeutic/toxic chemical basis of Kansui. Also, it has significance for drug discovery from terpenoids within the herb.

Metabolic profiling of outer fruit peels from 15 accessions of pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.) fruit peels are known to enrich the nutritional value of pomegranate juice due to their highly abundant phenolic metabolites such as hydrolyzable tannins (HTs), anthocyanins, and flavonoids, as well as the whole-fruit-based industrial extraction process. These shikimate pathway-derived metabolites also provide protection against pests and abiotic stresses for the fruit, and are important for the commercial trait of fruit peel color. To better understand the chemical diversity and biosynthetic relationships of phenolic metabolites in the outer fruit peel, we conducted metabolite profiling of outer peels from 15 pomegranate accessions largely varied in peel color using ultra high-performance liquid chromatography-diode array detection (uHPLC-DAD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 48 metabolites were (tentatively) identified through comparison to authentic standards, as well as MS or MS/MS spectral data in metabolomics databases. The 15 pomegranate accessions differ greatly in levels of anthocyanins, HTs, flavonoids, and other shikimate pathway-related metabolites, with the largest variations observed in the anthocyanin content. Negative correlations between HTs and flavonoids/anthocyanins, and between anthocyanins and proanthocyanins were observed, suggesting that these metabolites may compete for the same biosynthetic precursors for their production and are coordinately regulated.

Fractionation of Extracts from Black Chokeberry, Cranberry, and Pomegranate to Identify Compounds That Influence Lipid Metabolism.

Polyphenols show a spectrum of bioactive effects, including an influence on lipid metabolism. In this study, we performed activity-guided fractionations of black chokeberry (aronia), cranberry, and pomegranate extracts to identify the biologically active compounds. The extracts were prepared from fruit juice concentrates with the adsorbent resin Amberlite XAD-7 and were separated into a copigment and an anthocyanin fraction, followed by fractionation into a polymer and monomeric fraction by means of hexane precipitation. For further fractionation of the cranberry and pomegranate copigment fractions, high-performance countercurrent chromatography (HPCCC) was used. The compounds in each fraction were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS), and the quantification was performed by ultra high-performance liquid chromatography-diode array detector (UHPLC-DAD) analyses. Each of the (sub-)fractions was tested in three in vitro assays: phosphodiesterase 3B (PDE) activity, lipid accumulation, and lipolysis in 3T3-L1 cells. The results showed that various fractions and subfractions can inhibit lipid accumulation and PDE activity as well as increase lipolysis, particularly copigments. Overall, our results indicate an influence of polyphenol-rich (sub-)fractions on the lipid metabolism.

Chemical Characterisation, Antioxidant and Antibacterial Activities of Pinus pinaster Ait. and Pinus pinea L. Bark Polar Extracts: Prospecting Forestry By-Products as Renewable Sources of Bioactive Compounds

Agroforestry by-products have gained rising attention in recent years as they represent inexpensive and abundant raw materials that are a source of added-value chemicals, e.g., for food and pharmaceutical applications, as well as for bioenergy generation. Pinus pinaster Ait. bark extracts are consumed worldwide for their cardiovascular benefits, whilst the health potential of Pinus pinea L. bark has not yet been deeply exploited. Therefore, this study highlights the chemical characterisation of Portuguese P. pinaster Ait. and P. pinea L. bark polar extracts, via ultra-high performance liquid chromatography-diode array detection-tandem mass spectrometry (UHPLC-DAD-MSn) analysis, and their antioxidant and antibacterial activities. Quinic acid, an A-type procyanidin dimer isomer, protocatechuic acid, and quercetin were identified for the first time as P. pinea L. bark components. Moreover, this bark demonstrated a higher total content of identified polar compounds than P. pinaster Ait. bark, with quinic acid being the most abundant compound identified. Regarding antioxidant activity, the pine bark polar extracts exhibited strong reducing power and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) radical scavenging effects compared to natural antioxidants. Moreover, the bactericidal actions of pine bark extracts were shown against Staphylococcus aureus and Escherichia coli at a 3.13–25 mg mL−1 range. Globally, these promising insights can boost the sustainable exploitation of P. pinea L. bark, as already occurs with P. pinaster Ait. bark, for the food and biomedical fields.

UHPLC-DAD-ESI-MS analiza infuzije "Centaurium erythraea"

Chemical composition was estimated in a tea sample, i.e. infusion prepared from dried aerial herb of Centaurium erythraea. The plant was harvested in the Stara Planina mountain (Serbia, 42°43'00"N; 24°55'04"E) during the flowering stage. The flowering tops of the plant were dried to the moisture content of 7.89 (w/w) in a dark place. Qualitative analysis was done by Ultrahigh performance liquid chromatography-diode array detector-electrospray mass spectrometry (UH-PLC-DAD-ESI-MS/MS) method. The aim of this study was to detect and identify phytochemicals in the infusion prepared in a traditional way and present it as a good source of biologically active substances and bio-antioxidants. The analysis of C. erythraea infusion primarily indicated the presence of secoiridoid glycosides (sweroside, gentiopicroside, secologanoside, swertiamarin), xanthones and flavo-noids, which promises good quality of tea from Eastern Serbia.

Nickel(II) interactions with chlorophylls in solution: impact to degradation induced by UV-irradiation

Chlorophylls and metal substituted complexes of chlorophylls with known photosensitizing abilities can be used in many types of biological and solar energy applications; thus, it is important to analyze their basic properties when they are treated by visible light and/or UV radiation. Nickel(II) can replace central magnesium from chlorophyll (Chl) molecule to form a metal substituted, “central” Ni-Chl complex. So, the possible formation of nickel-chlorophyll complexes in 95% ethanol at 40 °C was studied by UHPLC-DAD chromatography (UltraHigh Performance Liquid Chromatography–Diode Array Detector). Nickel(II)-chlorophylls interactions in the reaction solutions at 40 °C lead not only to the formation of the Ni-related Chls, Ni-Chl complexes but several oxidation and demetalation products of chlorophylls. On the other hand, the influence of nickel(II) – chlorophyll interactions on chlorophylls solutions stability under continual UV-A, -B, and -C irradiation in 95% ethanol, was followed by UV-Vis spectrophotometry. Chlorophylls as well as their reaction solutions with nickel(II) undergo photochemical degradation obeying first- order kinetics. In general, the degradation is “energy-dependent”, i.e. proportional to the UV photons energy input. Chlorophylls are less stable than their reaction solutions with nickel(II), probably due to the higher stability of Ni-chlorophylls complexes, to all three subranges of UV- irradiation.

Modification of Natural Proanthocyanidin Oligomers and Polymers Via Chemical Oxidation under Alkaline Conditions.

We tested the susceptibility of 102 proanthocyanidin (PA)-rich plant extracts to oxidation under alkaline conditions and the possibility to produce chemically modified PAs via oxidation. Both the nonoxidized and the oxidized extracts were analyzed using group-specific ultrahigh-performance liquid chromatography–diode array detection–tandem mass spectrometry (UHPLC–DAD–MS/MS) methods capable of detecting procyanidin (PC) and prodelphinidin (PD) moieties along the two-dimensional (2D) chromatographic fingerprints of plant PAs. The results indicated different reactivities for PCs and PDs. When detected by UHPLC–DAD only, most of the PC-rich samples exhibited only a subtle change in their PA content, but the UHPLC–MS/MS quantitation showed that the decrease in the PC content varied by 0–100%. The main reaction route was concluded to be intramolecular. The PD-rich and galloylated PAs showed a different pattern with high reductions in the original PA content by both ultraviolet (UV) and MS/MS quantitation, accompanied by the shifted retention times of the chromatographic PA humps. In these samples, both intra- and intermolecular reactions were indicated.

Miracle Fruit Leaf Extract: Antioxidant Activity Evaluation, Constituent Identification, and Medical Applications

A systematic study was carried out on the antioxidants in miracle fruit leaf extract. The total phenols, total flavonoids, saponins and the antioxidant activities of the extract were evaluated using the 2,2′-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethyl-benzotiazolin-6-sulfonic acid (ABTS), metal chelating capacity (MCC) and ferric reducing antioxidant power (FRAP) assays. The results showed that the leaves contained high phenol concentrations of 90.0 ± 4.78 mg gallic acid equivalent/g dry weight, total flavonoids at 33.0 ± 1.92 mg rutin equivalent/g dry weight, and saponins at 27.8 ± 1.64 mg oleanolic acid equivalent/g dry weight. The extract possessed excellent free radical scavenging ability and high antioxidant capacities. Furthermore, eighteen polyphenol and flavonoid constituents in the extract were identified by using ultra-high performance liquid chromatography-diode array detector-tandem mass spectrometry (UPLC-DAD-MSn) method and standard chemicals. The constituents were gallic acid, 5-O-caffeoylquinic acid, 3-O-p-coumaroylquinic acid, 5-O-p-coumaroylquinic acid, 3-O-feruloylquinic acid, 4-O-caffeoylquinic acid, 4-O-p-coumaroylquinic acid dimer, 4-O-p-coumaroylquinic acid, 4-O-feruloylquinic acid, 4-O-feruloylquinic acid, rutin, myricetin-3-O-rhamnoside, quercetin-3-D-galactoside, quercetin-3-glucoside, kaempferol-3-O-glucoside, quercetin-3-rhamnoside, myricetin-O-galloylrhamnoside and quercetin-3-O-(2′′-galloyl)-rhamnoside.Eight constituents were quantified with values from 0.12 to 4.13 mg·g‒1. The extract of miracle fruit leaves was also used in an anti-Alzheimer's disease model for potential medical applications. The assay indicated that the extract provided apparent inhibition for the paralysis of Caenorhabditis elegans at a concentration of 0.02 mg·mL‒1. This work demonstrated that miracle fruit leaves are rich in bioactive antioxidants with potential for drug and functional product development.

Honey as Source of Nitrogen Compounds: Aromatic Amino Acids, Free Nucleosides and Their Derivatives.

The content of selected major nitrogen compounds including nucleosides and their derivatives was evaluated in 75 samples of seven varieties of honey (heather, buckwheat, black locust, goldenrod, canola, fir, linden) by targeted ultra-high performance liquid chromatography-diode array detector - high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-DAD-QqTOF-MS) and determined by UHPLC-DAD. The honey samples contained nucleosides, nucleobases and their derivatives (adenine: 8.9 to 18.4 mg/kg, xanthine: 1.2 to 3.3 mg/kg, uridine: 17.5 to 51.2 mg/kg, guanosine: 2.0 to 4.1 mg/kg; mean amounts), aromatic amino acids (tyrosine: 7.8 to 263.9 mg/kg, phenylalanine: 9.5 to 64.1 mg/kg; mean amounts). The amounts of compounds significantly differed between some honey types. For example, canola honey contained a much lower amount of uridine (17.5 ± 3.9 mg/kg) than black locust where it was most abundant (51.2 ± 7.8 mg/kg). The presence of free nucleosides and nucleobases in different honey varieties is reported first time and supports previous findings on medicinal activities of honey reported in the literature as well as traditional therapy and may contribute for their explanation. This applies, e.g., to the topical application of honey in herpes infections, as well as its beneficial activity on cognitive functions as nootropic and neuroprotective, in neuralgia and is also important for the understanding of nutritional values of honey.

Quantitative analysis of flavonols, flavonol glycoside and homoisoflavonoids in Polygonatum verticillatum using UHPLC‐DAD‐QTOF‐IMS and evaluation of their antioxidant potential

Polygonatum is widely used as a part of food in different regions of the world which covers five main categories such as drinks, vegetables, snacks, staple and seasoning foods. Presently, no analytical method is available for the quality control of Polygonatum. Development and validation of a method using ultrahigh-performance liquid chromatography diode array detector quadrupole time-of-flight (UHPLC-DAD/QTOF) technique for the estimation of six compounds including a flavonol glycoside [rutin (1)], two flavonols [quercetin (2) and kaempherol (3)] and three homoisoflavonoids [5,7-dihydroxy-3-(2-hydroxy-4-methoxybenzyl)-chroman-4-one (4), 5,7-dihydroxy-3-(2-hydroxy-4-methoxybenzyl)-8-methylchroman-4-one (5) and 5,7-dihydroxy-3-(4-methoxybenzyl)-8-methylchroman-4-one (6)]. In addition, screening of extract, fractions and compounds of P. verticillatum for antioxidant activity was also determined. The separation was achieved on C-18 column using acetonitrile and water containing 0.1% formic acid. The method was validated as per ICH (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use) guidelines. The validated method was applied for the simultaneous identification and quantification of compounds 1-6 in extract (E) and fractions (F1-F4) of P. verticillatum. Furthermore, antioxidant potential of E, F1 and F2 and compounds was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The method was within the linear range (r2 ) of 0.982 to 0.999, precise (intra- and inter-day percentage relative standard deviations < 2.72 and 2.26) and accurate with recoveries (89.1-98.3%). The limit of detection and limit of quantification were in the ranges 0.02-0.16 and 0.06-0.48 ng/mL, respectively. Compounds 1-6 were quantified in all the samples. Compounds 1, 2 and 5 showed higher activity with half maximal inhibitory concentration (IC50 ) values 0.41, 0.39, 0.72 at 10, 20 and 30 μg/mL, respectively. Developed method will be helpful to assess the quality of P. verticillatum raw material and their derived products.