Comparative Study of Fluorescence Emission of Fisetin, Luteolin and Quercetin Powders and Solutions: Further Evidence of the ESIPT Process.

Fisetin and Luteolin are important flavonoids produced in plants and known for their antioxidant, anti-inflammatory, neuroprotective, and analgesic properties. They are also good candidates for different types of biosensors. The model used to describe the fluorescence (FL) emission of these flavonoids involves an excited-state intermolecular proton transfer (ESIPT) process that causes a change in the molecule configuration and a corresponding decrease in the emission energy. Due to the different molecular structures of Fisetin and Luteolin, only one possible proton transfer within the molecule is allowed for each of them: transfer of the H3 proton for Fisetin and of the H5 for Luteolin. Here, we compare their calculated emission wavelengths, obtained using TDDFT/M06-2X/6-31++G(d,p), with their FL emission spectra measured on the corresponding powders and solutions and show that the experimental data are consistent with the presence of the ESIPT process. We also compare the emission wavelengths found for Fisetin and Luteolin with those calculated and measured for Quercetin, where, under photoexcitation, the transfers of both H3 and H5 protons are possible. We analyze the difference in the processes associated with the H3 and H5 proton transfers and discuss the reason for the predominance of the H5 proton transfer in Quercetin. Additionally, a new system of notation for flavonoid molecules is developed.

Grapevine varieties show different sensitivities to flavonoid alterations caused by high temperatures under two irrigation conditions.

This study aimed to assess the response of four red grapevine (Vitis vinifera L.) varieties to elevated temperature, drought and their combination, focusing on the concentration and profile of grape flavonoids. Fruit-bearing cuttings of Tempranillo, Cabernet Sauvignon, Merlot and Grenache grew in greenhouses under, either ambient temperature (T) or ambient temperature + 4 °C (T+4). Plants also received either full irrigation (FI, substrate field capacity) or deficit irrigation (DI, 50 % substrate field capacity). In general, T+4 decreased the concentration of anthocyanins, but DI mitigated this effect. T+4 and DI increased the abundance of methylated anthocyanins and flavonols with additive effects. Grapes under T+4 had higher abundance of acylated anthocyanins, while DI increased the proportion of tri-hydroxylated anthocyanins and flavonols. The impact of interacting elevated temperature and drought on grape composition was genotype dependent. In terms of anthocyanin concentration and profile, Tempranillo was the most affected variety, whereas Grenache was less sensitive.

Natural flavonols as probes for direct determination of borax: From conventional fluorescence analysis to paper-based smartphone sensing.

Borax is strictly regulated in the food processing and pharmaceutical industry due to its physiological toxicity, and the development of a direct analytical method is essential for effectively monitoring the borax abuse. In this work, the fluorescence properties of flavonoids, including flavones, isoflavones and flavonols, were systematically investigated from aqueous to borax solutions, and it was found that the weak intrinsic fluorescence of flavonols could be pervasively sensitized by borax. A natural flavonol, morin, was subsequently chosen as a representative probe to develop a turn-on fluorescence sensing method for borax analysis, which achieved a linear response spanning four orders of magnitude with a detection limit of 1.07 µM (0.22 µg mL-1 in terms of Na2B4O7 content). Furthermore, a smartphone-assisted paper-based test device was designed and constructed by 3D printing technology. Using morin-impregnated test strips as the carrier, the borax could be visually detected by the RGB signals of the captured images, with a detection limit of 0.13 mM (27.05 µg mL-1 for Na2B4O7). Combining ion exchange treatment for food samples and sodium periodate oxidation for drug samples, the developed methods were successfully applied for the direct analysis of borax in various products with the recoveries of 86.9-106.3% for traditional fluorescence analysis and 82.7-108.8% for smartphone-assisted fluorescence sensing. The fluorescence property of the morin-borax system was studied using time-dependent density functional theory, and the sensing mechanism was discussed in conjunction with experimental research.

A novel colormetric and light-up fluorescent sensor from flavonol derivative grafted cellulose for rapid and sensitive detection of Hg2+ and its applications in biological and environmental system.

Mercury ion (Hg2+) is one of harmful heavy metal ions that can accumulate inside the human organism and cause some health problems. In the article, a highly effective fluorescent probe named EC-T-PCBM was prepared by grafting flavonol derivatives onto ethyl cellulose for the specific recognition of Hg2+. EC-T-PCBM exhibited a remarkable fluorescence light-up response toward Hg2+ with excellent sensitivity. EC-T-PCBM possessed several prominent sensing properties for Hg2+, such as low detection limit (43.9 nM), short response time (5 min), and wide detection pH range (6-9). The response mechanism of EC-T-PCBM to Hg2+ has been verified through 1H NMR titration and DFT computation. Additionally, EC-T-PCBM not only can be used for accurately determining trace amount of Hg2+ in actual environmental water samples, but also can serve as a portable and rapid device by loading it on test strips for sensitive and selective visualization of Hg2+. More importantly, the confocal fluorescence imaging of onion cells suggested the favorable cell membrane permeability of EC-T-PCBM and its prominent ability to continuously monitor the enrichment from Hg2+ within fresh plant tissues.

Physicochemical properties, metabolomic analysis, antioxidant and lipid - lowering activity of a functional beverage based on cocona (Solanum sessiliflorum Dunal) / Propiedades fisicoquímicas, análisis metabolómico, actividad antioxidante e hipolipemiante de una bebida funcional a base de cocona (Solanum sessiliflorum Dunal)

The physicochemical, microbiological and metabolomics analysis, antioxidant and lipid - lowering effect, and shelf life prediction of a functional beverage based on cocona pul p of SRN9 ecotype was to carry out. According to the results obtained, the beverage complies with all the characteristics of the Peruvian technical standard for juices, nectars and fruit beverages NTP 203.110:2009 and is within the limits established by th e sanitary technical standard NTS N° 071 - MINSA/DIGESA - V.01, with a shelf - life period of 4 months and 1 day. The metabolome regarding bioactive compounds showed the presence of 30 compounds, including several glycosylated flavonols, two flavanols, and two s permidines. Likewise, showed a lipid - lowering effect statistically significant (p < 0.05) about the serum levels of total cholesterol and triglycerides, with a mean reduction of 41.52 mg/dL for total cholesterol levels and 130.80 mg/dL for triglyceride lev els. This beverage could be an alternative for the treatment of atherosclerosis and prevention of cardiovascular diseases.

Se rea lizó el análisis fisicoquímico, microbiológico y metabolómico, efecto antioxidante e hipolipemiante, y vida útil de una bebida funcional a base de cocona ecotipo SRN9. De acuerdo a los resultados, la bebida cumple con las características de la norma técnic a peruana para jugos, néctares y bebidas de frutas NTP 203.110:2009 y se encuentra dentro de los límites establecidos por la norma técnica sanitaria NTS N° 071 - MINSA/DIGESA - V.01, con una vida útil de 4 meses y 1 día. Del perfil metabolómico se identificaro n 30 compuestos, entre ellos varios flavonoles glicosilados, dos flavanoles y dos espermidinas. Asimismo, mostró un efecto hipolipemiante estadísticamente significativo (p < 0,05) sobre los niveles séricos de colesterol total y triglicéridos, con una reduc ción media de 41,52 mg/dL y de 130,80 mg/dL para los niveles de colesterol total y de triglicéridos, respectivamente. Esta bebida podría ser una alternativa para el tratamiento de la aterosclerosis y prevención de enfermedades cardiovasculares.

Dark-Chocolate-Coated BRS Clara Raisins: Phenolic Composition and Sensory Attributes.

Dark chocolate dragée confectionary was made with BRS Clara raisins pre-treated with extra virgin olive oil (EVOO). The evaluation of the changes in the phenolic composition (flavonols, hydrocinnamic acid derivatives (HCADs), stilbenes and flavan-3-ol monomers, dimers, and proanthocyanidins (PAs)) resulting from the covering process showed that the chocolate coating was responsible for an increase in the concentrations of flavan-3-ols and PAs when compared to just the raisins. For the flavonols and HCADs, a reduction in the total concentration of compounds was observed when comparing the dragées to the raisins. Furthermore, there was a strong influence of chocolate in the qualitative profile with the emergence of new compounds (quercetin-3-pentoside, kampfterol-3-rutinoside, p-coumaric acid, and caffeoyl-aspartate). The combination of these ingredients (raisins and chocolate) resulted in a dark chocolate coated raisin (DC) with good sensory acceptance and a more complex phenolic composition that may positively contribute to its functional quality.

Chemometrics-based investigation of non-volatiles/volatiles flavor of tencha (Camellia sinensis cv. Yabukita, Longjing 43 and Baiye 1).

The increasing demand for tea consumption calls for the development of more products with distinct characteristics. The sensory quality of tencha is significantly determined by innate differences among tea cultivars. However, the correlations between the chemical composition and sensory traits of tencha are still unclear. To enhance the understanding of the flavor formation mechanism in tencha and further to develop new cultivars resources, we investigated non-volatiles and volatile metabolites as well as sensory traits in tencha from different tea cultivars (Camellia sinensis cv. Yabukita, Longjing 43 and Baiye 1); the relationships between the flavor traits and non-volatiles/volatiles were further evaluated by partial least squares - discriminate analysis (PLS-DA), multiple factor analysis (MFA) and multidimensional alignment (MDA) analysis. A total of 64 non-volatiles and 116 volatiles were detected in all samples, among which 71 metabolites were identified as key flavor-chemical contributors involving amino acids, flavonol glycosides, flavones, catechins, ketones, alcohols, hydrocarbons, aldehydes, esters and acids. The levels of taste-related amino acids, flavonol glycosides and gallic acid varied significantly among the tencha samples made from different tea cultivars. All the samples exhibited typical quality characteristics of tencha. The tencha from Camellia sinensis cv. Longjing 43 and Camellia sinensis cv. Baiye 1 (cultivated in the open) exhibited higher levels of amino acids and gallic acid, which were associated with the umami taste and mellow taste of tea infusion. Abundant flavonol glycosides were related to the astringency, while partial tri-glycosides specifically quercetin-3-O-galactoside-rhamnoside-glucoside and total of flavonol galactoside-rhamnoside-glucoside were associated with mellow taste. The floral alcohols were identified as significant contributors to the refreshing aroma traits of tencha. The green, almond-like, acidic and fruity odorants were associated with a green and fresh aroma, while the green, cheesy and waxy odorants such as ketones, esters, acids and hydrocarbons were associated with seaweed-like aroma. This study provides insight into sensory-related chemical profiles of tencha from different tea cultivars, supplying valuable information on flavor and quality identification for tencha.

Peculiarities of the Variation of Biologically Active Compounds in Fruit of Vaccinium oxycoccos L. Growing in the Cepkeliai State Strict Nature Reserve.

This study was carried out to analyze the accumulation patterns of anthocyanins, proanthocyanidins, flavonols, chlorogenic acid, and triterpene compounds in fruit samples of Vaccinium oxycoccos L. berries growing in the Cepkeliai State Strict Nature Reserve in Lithuania. Studies were carried out on the phytochemical composition of cranberry fruit samples during the period of 2020-2022. Anthocyanins, flavonols, chlorogenic acid and triterpene compounds were identified and quantified using UPLC-DAD methods, and proanthocyanins were determined using spectrophotometric methods. The content of identified compounds varied, as reflected in the total amounts of anthocyanins (710.3 ± 40 µg/g to 6993.8 ± 119 µg/g), proanthocyanidins (378.4 ± 10 µg EE/g to 3557. 3 ± 75 µg EE/g), flavonols (479.6 ± 9 µg/g to 7291.2 ± 226 µg/g), chlorogenic acid (68.0 ± 1 µg/g to 3858.2 ± 119 µg/g), and triterpenoids (3780.8 ± 98 µg/g to 7226.9 ± 224 µg/g). Cranberry fruit samples harvested from open oligotrophic wetland habitats contained higher levels of anthocyanins, anthocyanidins, flavonol glycosides, and proanthocyanidins. The highest levels of triterpene compounds were found in the cranberry fruits harvested in the spring of the following year after the snowmelt. The use of principal component analysis showed that cranberry plant material harvested in October and November had higher levels of bioactive compounds.

GABase and glutaminase inhibitory activities of herbal extracts and acylated flavonol monoglycosides isolated from the leaves of Laurus nobilis L.

This study was to compare GABase [a mixture of γ-aminobutyric acid (GABA) aminotransferase and succinic semialdehyde dehydrogenase] and glutaminase inhibitory activities of 20 herbal extracts and investigate the isolation, structural elucidation and those inhibitory activities of three acylated flavonol monoglycosides from the selected extract of Laurus nobilis L. (laurel). On the basis of the NMR spectroscopic data and the ESI MS spectra together with the comparison with the literature values, three compounds were identified as kaempferol-3-O-(4″-E-p-coumaroyl)-α-l-rhamnopyranoside (1), kaempferol-3-O-(3″,4″-di-E-p-coumaroyl)-α-l-rhamnopyranoside (2) and kaempferol-3-O-(2″,4″-di-E-p-coumaroyl)-α-l-rhamnopyranoside (3), respectively. The IC50 values of GABase inhibitory activity of 1-3 and p-hydroxybenzaldehyde (HBA) as control were 0.24 mM, 0.14 mM, 0.12 mM and 0.43 mM, respectively. Additionally, the IC50 values of glutaminase inhibitory activity of 1-3 and 6-diazo-5-oxo-l-norleucine (DON) as control were 0.34 mM, 0.13 mM, 0.14 mM and 0.33 mM, respectively. The results suggest that the extract from laurel shows the strongest biological activities among 20 herbal extracts and three acylated flavonol monoglycosides may serve as potential lead compounds for the prevention and treatment of neurodegenerative and lifestyle-related diseases by targeting GABase and glutaminase. This is the first report on GABase and glutaminase inhibitory activities of 1-3.

Dracocephalum jacutense Peschkova from Yakutia: Extraction and Mass Spectrometric Characterization of 128 Chemical Compounds.

Dracocephalum jacutense Peschkova is a rare and endangered species of the genus Dracocephalum of the Lamiaceae family. The species was first described in 1997 and listed in the Red Data Book of Yakutia. Significant differences in the multicomponent composition of extracts from D. jacutense collected in the natural environment and successfully introduced in the Botanical Garden of Yakutsk were identified by a team of authors earlier in a large study. In this work, we studied the chemical composition of the leaves, stem, and inflorescences of D. jacutense using the tandem mass spectrometry method. Only three cenopopulations of D. jacutense were found by us in the territory of the early habitat-in the vicinity of the village of Sangar, Kobyaysky district of Yakutia. The aboveground phytomass of the plant was collected, processed and dried as separate parts of the plant: inflorescences, stem and leaves. Firstly, a total of 128 compounds, 70% of which are polyphenols, were tentatively identified in extracts of D. jacutense. These polyphenol compounds were classified as 32 flavones, 12 flavonols, 6 flavan-3-ols, 7 flavanones, 17 phenolic acids, 2 lignans, 1 dihydrochalcone, 4 coumarins, and 8 anthocyanidins. Other chemical groups were presented as carotenoids, omega-3-fatty acids, omega-5-fatty acids, amino acids, purines, alkaloids, and sterols. The inflorescences are the richest in polyphenols (73 polyphenolic compounds were identified), while 33 and 22 polyphenols were found in the leaves and stems, respectively. A high level of identity for polyphenolic compounds in different parts of the plant is noted for flavanones (80%), followed by flavonols (25%), phenolic acids (15%), and flavones (13%). Furthermore, 78 compounds were identified for the first time in representatives of the genus Dracocephalum, including 50 polyphenolic compounds and 28 compounds of other chemical groups. The obtained results testify to the unique composition of polyphenolic compounds in different parts of D. jacutense.

Identification and characterisation of MdUGT78T2 as a galactosyltransferase with dual activity on flavonol and anthocyanidin substrates in red-skinned apple fruit (Malus domestica L.).

Anthocyanidin and flavonol glycosides have been linked to the health-promoting effects associated with apple consumption. However, very few enzymes involved in flavonoid glycosylation have been characterised to date. Here, we present the identification and phylogenetic analysis of 234 putative glycosyltransferases involved in flavonoid biosynthesis, and detail the biochemical and structural characterisation of MdUGT78T2 as a strict galactosyltransferase involved in the formation of quercetin-3-O-galactoside and cyanidin-3-O-galactoside, the major glycoconjugates of flavonoids in apple. The enzyme is also active on other flavonoids but with a lower catalytic efficiency. Our data, complemented with gene expression analysis suggest that MdUGT78T2 synthesises the glycoconjugates at both the early and late stages of fruit development. This newly discovered type of catalytic activity can potentially be exploited for in vitro modification of flavonoids to increase their stability in food products and to modify apple fruits and other commercial crops through breeding approaches to enhance their health benefits.

Bioactive Compounds and Antioxidant Activity in the Fruit of Rosehip (Rosa canina L. and Rosa rubiginosa L.).

Rosehips (Rosa spp., Rosaceae) are wild rose bushes with more than 100 species. Its fruits vary in colour and size, depending on the species, and are recognised for their nutritional characteristics. Ten samples of Rosa canina L. and Rosa rubiginosa L. fruits were collected at different geographical points from Southern Chile. Nutrients such as crude protein and minerals and functional properties such as phenolic compounds, ascorbic acid, and also antioxidant activities were evaluated by HPLC-DAD-ESI-MS/MS. The results revealed a high content of bioactive compounds, primarily ascorbic acid (6.0 to 8.2 mg g-1 fresh weight (FW)), flavonols (427.9 ± 0.4 µg g-1 FW) and antioxidant activity. We established a relationship between the antioxidant activity using Trolox equivalent antioxidant capacity (TEAC), cupric reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl radical (DPPH) methods and the concentration of uncoloured compounds, such as flavonols and catechin. This antioxidant activity was primarily associated with the samples from Gorbea, Lonquimay, Loncoche, and Villarrica localities, and all of them were of the species Rosa rubiginosa L. The results here obtained represent novel information of rosehip fruits. In this sense, the reported information about compounds and antioxidant activities in rosehip fruits allowed us to continue new lines of research in relation to the potential formulation of new functional foods and also in the treatment and/or prevention of some diseases.

Analysis of proanthocyanidins and flavonols in the seedpods of Chinese Antique Lotus: A rich source of antioxidants.

Antique Lotus (Nelumbo) is a perennial aquatic plant with unique historical significance and cultural value, whereas its potential economic value hasn't been fully explored. The present study showed that lotus seedpods had significantly higher antioxidant capacity than other parts by FRAP, ABTS, and ORAC assays and analyzed the proanthocyanidins and flavonols in the seedpods of Antique Lotus. Polyphenols contributed to great antioxidant activity and 51 polyphenols were identified by UPLC-TQ-MS analysis. In which, 27 compounds were identified from lotus seedpods for the first time, including 20 trimers, 5 dimers and 2 tetramers of proanthocyanidin. Total proanthocyanidins explained 70%-90% of the different antioxidant activities and the content of proanthocyanidin trimers showed the strongest correlations with the antioxidant activities. This study provided a fundamental reference for the research of polyphenols in lotus and found that Antique Lotus seedpod extracts have the promising prospects of additives used in feed and food processing.

Metabolomics provide a novel interpretation of the changes in flavonoids during sea buckthorn (Hippophae rhamnoides L.) drying.

Flavonoids are major nutrients in sea buckthorn berries. However, the effects of drying methods on flavonoids in sea buckthorn berries are unclear. In this study, ultra-performance liquid chromatography and metabolomics were adopted to analyse the effects of hot air drying (HAD) and infrared drying (IRD) on flavonoid compounds and antioxidant capacity in sea buckthorn berries. In total, 97 metabolites belonging to 12 classes were identified, including 26 flavones, 23 flavonols, and 11 flavanones. Additionally, 32 differential metabolites were identified among groups. Isorhamnetin and quercetin contents increased in response to HAD and IRD, while (-)-epigallocatechin and (-)-gallocatechin contents decreased. Differential metabolism of flavonoid compounds occurred mainly via the flavonoid biosynthesis and secondary metabolite biosynthesis pathways. Flavonoid compound degradation might be associated with antioxidant activity during drying. This study elucidated the effect of drying on nutritional components of sea buckthorn berries and may guide the improvement of quality during food processing.

The Relationship between Dietary Flavonols Intake and Metabolic Syndrome in Polish Adults.

Metabolic syndrome (MetS) is a cluster of metabolic disorders primarily caused by central obesity, which results in chronic inflammation leading to hypertension, diabetes and atherogenic dyslipidemia. Inflammation underlying MetS could be the target for dietary flavonols as they present antioxidative properties. The aim of this paper was to analyze the differences in habitual intake of selected flavonols (quercetin, kaempferol, isorhamnetin and myricetin) between MetS patients and healthy participants, and its relationship with MetS advancement. Ninety participants were enrolled in this study. The one-year flavonol intake was assessed with a dedicated food frequency questionnaire. The patients with MetS consumed significantly less quercetin (p = 0.01), kaempferol (p = 0.04), isorhamnetin (p < 0.001), total flavonols (p = 0.01), tomatoes (p = 0.001) and wine (p = 0.01) daily. Further analysis revealed a moderate inverse correlation between quercetin (p = 0.001), kaempferol (p = 0.01), isorhamnetin (p < 0.001), total flavonols (p = 0.001) and tomato consumption (p = 0.004) and MetS stage. The analysis of laboratory parameters showed that dietary intake of flavonols was not correlated with lipid profile, glucose level or renal function. On the basis of this observation, a potential protective effect of dietary flavonols, mainly from tomatoes, against MetS could be suggested. However, when referring to MetS components, flavonols probably mainly impact central obesity and blood pressure, without a significant impact on conventional lipid-profile parameters and glucose level.

Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based metabolomics to clarify the mechanism of color change of saffron floral bio-residues.

Saffron floral bio-residues (SFB) are a valuable natural source of antioxidants and dyes that can contribute to the development of new food products and cosmetic products. Color change was usually observed during SFB storage, which may result in quality degradation of SFB or even cause potential hazard to human health. In order to clarify the mechanism of color change of SFB sample, the chemical differences among SFB samples stored under different conditions were analyzed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and chemometrics methods, from which differential flavonols and anthocyanins were screened and their kinetic variations during sample storage summarized. In addition, the color change of the SFB sample was digitalized using an electronic eye (E-eye), which was found to be related to the content of delphinidin-3,5-di-O-glucoside (DDG). Moreover, the degradation kinetic parameters of DDG under different storage conditions were studied. In conclusion, the variation of kaempferol-, isorhamnetin-, and quercetin-type flavonol, and delphinidin- and petunidin-type anthocyanin resulted in the color change of SFB sample, and anthocyanin was found more unstable than flavonol. PRACTICAL APPLICATION: Saffron floral bio-residues (SFB) are popular natural sources of antioxidants and colorants that can be used in food and cosmetic products. Color change usually occurs during SFB storage period. Clarifying the mechanism of the color change of SFB will help us to ensure the quality of SFB.

Genetic Diversity for Quercetin, Myricetin, Cyanidin, and Delphinidin Concentrations in 38 Blackeye Pea (Vigna unguiculata L. Walp.) Genotypes for Potential Use as a Functional Health Vegetable.

Blackeye peas (Vigna unguiculata L. Walp.) are mainly used as a vegetable throughout the world, however they may contain significant concentrations of quercetin, myricetin, cyanidin, and delphinidin for potential use as a functional vegetable. Thirty-eight blackeye pea genotypes were selected from the core collection in the USDA, ARS, Plant Genetic Resources Conservation Unit's cold storage at 4 °C during 2016. Information regarding concentrations of quercetin, myricetin, cyanidin, delphindin, and correlations among these as well as additional seed traits including seed coat color, seed pattern color, seed pattern, seed texture, and years in storage would add value to the blackeye pea genotypes for use as a functional vegetable. Using high performance liquid chromatography (HPLC), the red seeded accession originating from Mozambique, PI 367927 produced the highest quercetin (469.53 µg/g) and myricetin (212.23 µg/g) concentrations. The black seeded genotype, PI 353236, originating from India, produced the highest cyanidin (1,388.82 µg/g) concentration. However, PI 353236 and the brown seeded genotype, PI 353352 from India produced the highest concentrations of delphinidin (1,343.27 and 1,353.94 µg/g), respectively. Several correlations were observed and interestingly only delphinidin showed a significant negative correlation (r = -0.293*) with years in cold storage indicating that delphinidin declined in the seeds stored the longest (from 4-45 years) at 4 °C. Principal component analysis (PCA) explained how the flavonols, anthocyanidins, and the additional seed traits contributed to the variation of the blackeye pea genotypes. The cluster analysis showed six clusters representing low to high phytochemical concentrations. The genetic parameters including σ2g, σ2p, GCV, PCV, h2h, and GG indicate that improvement in these phytochemical traits is possible through selection. The genotypic and phenotypic correlations showed that improving one phytochemical significantly improved the other except for cyanidin with delphinidin. These results can be used by scientists to develop blackeye pea cultivars with high flavonol and anthocyanidin concentrations.

Copigmentation effect of flavonols on anthocyanins in black mulberry juice and their interaction mechanism investigation.

Copigmentation effect of flavonoids on black mulberry juice and its main anthocyanin, cyanidin-3-O-glucoside (C3G), was evaluated. Results showed that the hyperchromic effect of flavonols, such as kaempferol (KAE), hyperoside (HYP), rutin (RUT), quercetin (QTI) and isoquercitrin (IQT), was better than that of quercitrin (QTR) and catechin (CAT). The degradation rate constant (k) of C3G decreased by 8.6 %∼50.0 % when KAE, HYP, RUT, QTI and IQT were added, whilst half-life (t1/2), activation energy (Ea) and hydration reaction equilibrium constant (pKh) increased by 7.4 %∼99.0 %, 60.0 %∼95.7 % and 8.3 %∼37.8 % respectively. Meanwhile, the maximum absorption wavelength of the mixture displayed bathochromic shift. Molecular simulation indicated that the interaction energy with C3G was KAE > HYP > RUT > QTI > IQT > QTR > CAT. The main driving force forming C3G-flavonol complex were hydrogen bond and Van der Waals interaction. These results will provide theoretical reference to enhance color stability of food rich in anthocyanins.

Quality evaluation of ginkgo biloba leaves based on non-targeted metabolomics and representative ingredient quantification.

Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) combined with multivariate statistical analysis was applied to the study of plant metabolomics to reveal the factors affecting the content of ginkgo leaf compounds. As a follow-up analysis, the terpene lactones and ginkgolic acids were quantified simultaneously using ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QqQ-MS/MS), and subsequently total flavonol glycosides were quantified by high-performance liquid chromatography (HPLC). The results revealed that a total of 52 compounds were potentially identified by establishing a database, and 10 compounds were verified by reference standards; terpene lactones, ginkgolic acids, and flavonoids were the differential compounds; and ginkgolide A was identified as an important indicator compound for tree age. In addition, quantitative analysis showed that the contents of total flavonol glycosides and terpene lactones were highest during April and August in young ginkgo leaves, and differed based on origin. In summary, numerous compounds were rapidly detected by liquid chromatography coupled with MS, the ginkgo leaf samples were compared, and the differential metabolites were screened out. The content changing rules of the target compounds in ginkgo leaves from different regions with different tree ages and harvesting periods were clarified.

Determination of the polyphenolic content of berry juices using focusing-modulated comprehensive two-dimensional liquid chromatography coupled to mass spectrometry detection.

In this work, a comprehensive two-dimensional liquid chromatography system, comprised of a ZIC-HILIC and C18 columns in the first and second dimensions, respectively, was tuned and employed for attaining high resolution profiles of the polyphenolic pattern in seven commercial berry juices. The developed HILIC × RP-LC method was validated in terms of linearity range, correlation coefficients, limit of detection, limit of quantification, precision (intra- and inter-day), and recovery. A total of 104 polyphenolic compounds belonging to different chemical classes (hydroxybenzoic and cinnamic acid derivatives, flavone glycosides, flavonols, flavonol glycosides, dihydroflavonols, and anthocyanin glycosides) have been characterized and quantified in the juices investigated. Despite the constituents being similar, a notable quantitative variation among the analyzed berry species was observed. Elderberry contained the highest amount of polyphenols (918 ± 1.10 mg 100 mL-1), followed by chokeberry (516 ± 0.08 mg 100 mL-1). On the other hand, raspberry contained the lowest amount (104 ± 1.21 mg 100 mL-1). Further, total phenolic, flavonoid, and anthocyanin contents were determined spectrophotometrically, yielding consistent results. The free-radical scavenging activity (DPPH test) and reducing power of the juices, expressed as IC50 (µL mL-1) and mg ASE mL-1, varied from 2.79 ± 0.03 (honeyberry) to 31.66 ± 0.02 (blueberry) and from 1.71 ± 0.01 (blueberry) to 8.89 ± 0.12 (chokeberry), respectively. Such a ZIC-HILIC × C18 platform based on focusing modulation, never employed so far for berry juices, showed a remarkable separation capability with high values of corrected peak capacity (up to 1372) and orthogonality (Ao up to 0.80), thus providing a great applicability to be advantageously employed for other complex food samples.