A selective bis-thiophene chalcone-based spectrofluorimetric sensor for Fe3.

A highly selective bis thiophene-based chalcone as a chemosensor for detecting Fe3+ metal ions in DMF: H2O (9:1). This sensor was selective toward ferric ions over other metal ions with a detection limit in micromolar range.

Tracking the effect of roasting and fermentation on the metabolites of licorice root (Glycyrrhiza glabra L.) using UPLC-MS analysis combined with multivariate statistical analysis.

BACKGROUND: Roasting, honey-roasting and fermentation are the most common pre-processing procedures of licorice roots. They were shown to noticeably change the composition of extracts. In this work, the common alterations in licorice secondary metabolites by processing were interpreted. Comprehensive metabolic profiling of different studied samples was undergone. METHODS: UPLC-QqQ-MS/MS analysis coupled to various chemometric analysis models was implemented to unravel the effect of different pre-processing procedures on the chemical profile of licorice samples. RESULTS: UPLC-QqQ-MS/MS analysis designated 133 chromatographic peaks with saponins, flavonoids, chalcones and pterocarpans being the most abundant groups. Triterpene saponins dominated the secondary metabolites in the aqueous extracts, with fermented samples showing the highest relative amounts. Meanwhile the ethanol extracts showed significant amounts of chalcones. Melanoidins were only detected in roasted and honey roasted samples. Multivariate models indicated that roasting of samples induced a greater effect on the polar metabolites rather than nonpolar ones. Variable of importance (VIP) plot indicated that glycyrrhizin and its hydrolysis product glycyrrhetinic acid, trihdroxychalcone diglycoside, glabrone and glabridin are the main chemical features responsible for the discrimination of samples. CONCLUSION: Coupling UPLC-MS/MS to multivariate analysis was a successful tool that unveiled the significant effect of different pre-processing methods on the chemical profile of processed and unprocessed licorice samples. Moreover, such coupling unraveled the discriminatory chemical compounds among tested samples that can be employed as markers for the processing procedure of licorice.

Valorisation of liquorice (Glycyrrhiza) roots: antimicrobial activity and cytotoxicity of prenylated (iso)flavonoids and chalcones from liquorice spent (G. glabra, G. inflata, and G. uralensis).

Prenylated phenolics are antimicrobials found in liquorice (Glycyrrhiza spp.). Liquorice spent is a by-product rich in prenylated phenolics obtained after water extraction of roots, and is currently not valorised. We analysed the prenylated phenolics composition of spent extracts from Glycyrrhiza glabra, G. inflata, and G. uralensis, their antimicrobial activity, cytotoxicity, and effects on Caco-2 cell viability. G. glabra, G. inflata, and G. uralensis spent extracts showed distinct phytochemical profiles. Antibacterial activity (Lactobacillus buchneri, Streptococcus mutans, and Staphylococcus aureus) of G. uralensis and G. inflata (MICs 25-250 µg mL-1) was higher than of G. glabra (MICs 75-1000 µg mL-1). Marker compounds glabridin, licochalcone A, and glycycoumarin were equally potent (MICs 12.5-25 µg mL-1). G. inflata and G. uralensis showed cytotoxicity at 500 µg mL-1, whereas G. glabra was not toxic up to 1000 µg mL-1, but showed reduced viability between 50-500 µg mL-1. Linking antibacterial activity of the liquorice spent extracts with cell viability showed that MICs against S. aureus coincide with concentrations where cell viability was not reduced, whereas for the other bacteria and yeasts MICs concurred at concentrations where cell viability was reduced. In this study we show that liquorice spent is a by-product rich in antibacterial prenylated phenolics that offers interesting oppurtunities for e.g. control of microorganisms and the discovery of novel plant-derived antimicrobials.

Qualitative Analysis Related to Palynological Characterization and Biological Evaluation of Propolis from Prespa National Park (Greece).

Propolis samples from a geographical part of northwest Greece (Prespa National Park, PNP), which is characterized as a plant endemism center and biodiversity hotspot, were characterized through pollen analysis, chemically analyzed, and biologically evaluated. The majority of the studied propolis showed typical chemical constituents (phenolic acids, flavonoids, and chalcones) of European type, while a sample of Mediterranean-type propolis (rich in diterpenes) was also identified. The palynological characterization was implemented to determine the botanical origin and to explain the chemical composition. The total phenolic content and the DPPH assay showed that the European-type propolis samples possessed strong antioxidant activity (86-91% inhibition at 200 µg/mL). Moreover, promising antibacterial activity of the extracts (MIC values 0.56-1.95 mg/mL) and moderate antifungal activity (MIC values 1.13-2.40 mg/mL) were noticed, while the sample with the highest activity had a significant content in terpenes (Mediterranean type). Propolis samples from the PNP area represent a rich source of antibacterial and antioxidant compounds and confirm the fact that propolis is a significant natural product with potential use for improving human health and stimulating the body's defense. Finally, it is noteworthy that a significant chemical diversity was demonstrated, even in samples from a limited geographical area as this of PNP.

Impact of Tralopyril and Triazolyl Glycosylated Chalcone in Human Retinal Cells' Lipidome.

Antifouling (AF) coatings containing booster biocides are used worldwide as one of the most cost-effective ways to prevent the attachment of marine organisms to submerged structures. Nevertheless, many of the commercial biocides, such as Econea® (tralopyril), are toxic in marine environments. For that reason, it is of extreme importance that new efficient AF compounds that do not cause any harm to non-target organisms and humans are designed. In this study, we measured the half-maximal inhibitory concentration (IC50) of a promising nature-inspired AF compound, a triazolyl glycosylated chalcone (compound 1), in an immortalized human retinal pigment epithelial cell line (hTERT-RPE-1) and compared the results with the commercial biocide Econea®. We also investigated the effects of these biocides on the cellular lipidome following an acute (24 h) exposure using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). Our results showed that compound 1 did not affect viability in hTERT-RPE-1 cells at low concentrations (1 µM), in contrast to Econea®, which caused a 40% reduction in cell viability. In total, 71 lipids were found to be regulated upon exposure to 10 µM of both compounds. Interestingly, both compounds induced changes in lipids involved in cell death, membrane modeling, lipid storage, and oxidative stress, but often in opposing directions. In general, Econea® exposure was associated with an increase in lipid concentrations, while compound 1 exposure resulted in lipid depletion. Our study showed that exposure to human cells at sublethal Econea® concentrations results in the modulation of several lipids that are linked to cell death and survival.

Genetic mapping of sexually dimorphic volatile and non-volatile floral secondary chemistry of a dioecious willow.

Secondary chemistry often differs between sexes in dioecious plant species, a pattern attributed to its possible role in the evolution and/or maintenance of dioecy. We used GC-MS to measure floral volatiles emitted from, and LC-MS to quantitate non-volatile secondary compounds contained in, female and male Salix purpurea willow catkins from an F2 family. Using the abundance of these chemicals, we then performed quantitative trait locus (QTL) mapping to locate them on the genome, identified biosynthetic candidate genes in the QTL intervals, and examined expression patterns of candidate genes using RNA-seq. Male flowers emitted more total terpenoids than females, but females produced more benzenoids. Male tissue contained greater amounts of phenolic glycosides, but females had more chalcones and flavonoids. A flavonoid pigment and a spermidine derivative were found only in males. Male catkins were almost twice the mass of females. Forty-two QTL were mapped for 25 chemical traits and catkin mass across 16 of the 19 S. purpurea chromosomes. Several candidate genes were identified, including a chalcone isomerase associated with seven compounds. A better understanding of the genetic basis of the sexually dimorphic chemistry of a dioecious species may shed light on how chemically mediated ecological interactions may have helped in the evolution and maintenance of dioecy.

Preliminary study on the possible impact of Thalassodendron ciliatum (Forss.) den Hartog acidic polysaccharide fractions against TAA induced liver failure.

The water-soluble acidic polysaccharide from Thalassodendron ciliatum (Forss.) den Hartog was successfully extracted, fractionated and purified. The phytochemical profile of the two water-soluble fractions (F1 and F2), were detected using different analytic techniques. GC-MS analysis revealed the presence of 22 saccharide. Acidic polysaccharide, galacturonic and glucuronic acid were the most abundant. Moreover, paper chromatography and electrophoresis also performed as a preliminary chemical characterization of the polymer. The hepatoprotective activity of the fractions against thioacetamide (TAA) induced liver failure; antioxidant potential and preliminary immunomodulatory activity were assigned in-vivo. The results revealed a potent competence to improve the liver function profile (ALT, AST, total bilirubin, total glyceride, etc.) and a remarkable improvement in liver architecture in comparison to the challenged intoxicated groups. Moreover, they showed high anti-oxidative properties and a promising immunomodulatory influence via Il6. These findings provide new insight into the possible role of polysaccharide purified two fractions in the treatment of acute liver injury.

MS-based metabolite analysis of two licorice chalcones in mice plasma, bile, feces, and urine after oral administration.

Isoliquiritigenin (ILG) and isoliquiritin (ILQ), two kinds of major flavonoids in licorice, are biological active substances with antioxidant, anti-inflammatory, and tumor-suppressive effects. However, their in vivo metabolites, possible material basis of this two licorice chalcones for the treatment of diseases, have not been studied completely. To determine the metabolism of ILG and ILQ, after oral administration of 100 mg/kg/day of these compounds for consecutive 8 days, the metabolites of these two licorice chalcones in mice plasma, urine, feces, and bile were determined using liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry in this study. The structures of those metabolites were tentatively identified according to their fragment pathways, accurate masses, characteristic product ions, metabolism law, and reference standards-matching. As a result, a total of 25 and 29 metabolites of ILG and ILQ were identified, respectively. Seven main metabolic pathways, oxidation and reduction, deglycosylation and glycosylation, dehydroxylation and hydroxylation, demethoxylation and methoxylation, acetylation, glucuronidation, and sulfation, were summarized to tentatively explain how the metabolites were biologically transformed. These results provide the important information on the metabolism of ILG and ILQ, which may be helpful for the further research of their pharmacological mechanism.

Ultrastructural alterations in Plasmodium falciparum induced by chalcone derivatives.

OBJECTIVE: Chalcones (1, 3-diaryl-2-propen-1-ones) and their derivatives are widely explored from the past decade for its antimalarial activity. To elucidate their mechanism of action on the malaria parasite, the ultrastructural changes with the action of these derivatives in different organelles of the parasite were studied in vitro. Infected RBCs [CQ sensitive (MRC-2) and CQ resistant (RKL-9) Plasmodium strain] were treated with three chalcone derivatives 1, 2 and 3 and standard drugs, i.e., CQ and artemisinin at twice their respective IC50 values for 24 h and then harvested, washed, fixed, embedded and stained to visualize ultra-structure changes before and after intervention of treatment under in vitro condition through transmission electron microscope. RESULTS: The ultrastructural changes demonstrate the significant disturbance of all parasite membranes, including those of the nucleus, mitochondria and food vacuole, in association with a marked reduction of ribosomes in the trophozoites and cessation of developing schizonts which suggest multiple mechanisms of action by which chalcone derivatives act on the malaria parasite. The present study opens up perspectives for further exploration of these derivatives in vivo malaria model to discover more about its effect and mechanism of action.

Dalbergia ecastaphyllum (L.) Taub. and Symphonia globulifera L.f.: The Botanical Sources of Isoflavonoids and Benzophenones in Brazilian Red Propolis.

The Brazilian red propolis (BRP) constitutes an important commercial asset for northeast Brazilian beekeepers. The role of Dalbergia ecastaphyllum (L.) Taub. (Fabaceae) as the main botanical source of this propolis has been previously confirmed. However, in addition to isoflavonoids and other phenolics, which are present in the resin of D. ecastaphyllum, samples of BRP are reported to contain substantial amounts of polyprenylated benzophenones, whose botanical source was unknown. Therefore, field surveys, phytochemical and chromatographic analyses were undertaken to confirm the botanical sources of the red propolis produced in apiaries located in Canavieiras, Bahia, Brazil. The results confirmed D. ecastaphyllum as the botanical source of liquiritigenin (1), isoliquiritigenin (2), formononetin (3), vestitol (4), neovestitol (5), medicarpin (6), and 7-O-neovestitol (7), while Symphonia globulifera L.f. (Clusiaceae) is herein reported for the first time as the botanical source of polyprenylated benzophenones, mainly guttiferone E (8) and oblongifolin B (9), as well as the triterpenoids ß-amyrin (10) and glutinol (11). The chemotaxonomic and economic significance of the occurrence of polyprenylated benzophenones in red propolis is discussed.

Surface area expansion by flower-like nanoscale layered double hydroxides for high efficient stir bar sorptive extraction.

Enhancing the surface area of stationary phase is essential in chromatographic science. In this work, nanoscale NiAl-layered double hydroxides (NiAl-LDHs) with flower-like structure was used as a platform for supporting the stationary phase. Then strong hydrophobic p-naphtholbenzein molecule was immobilized onto the LDHs layer as sorbent for stir bar sorptive extraction (SBSE). The flower-like LDHs layer significantly increased the extraction efficiency through increasing the specific surface area and immobilized amounts of stationary phase. In addition, the LDHs can also provide anion exchange ability, which expanded the application of this stir bar for analysis of not only hydrophobic but also anionic analytes. For improving the workability, a poly(ether ether ketone) (PEEK) jacket stir bar with detachable dumbbell-shaped structure was employed. The PEEK jacket with high mechanical strength and dumbbell-shaped structure improved the durability of stir bar and the detectable design allowed elution to be realized with less solvent that enhanced the enrichment factor. The proposed stir bar showed good performance for the extraction of multiple analytes including flavonoids, non-steroid anti-inflammatory drugs and chlorophenoxy acids. By coupling with high performance liquid chromatography-ultraviolet detection (HPLC-UV), the SBSE-HPLC-UV method was applied for the extraction of three active components including bavachin, isobavachalcone and bavachinin in Psoralea corylifolia L. herb with low limit detection of 0.01-0.02 ng/mL.

Heterocycles 51: Liphophilicity investigation of some thiazole chalcones and aurones by experimental and theoretical methods.

Reversed-phase thin-layer chromatography and reversed-phase high-performance liquid chromatography were used for lipophilicity determination of a library of 30 thiazole chalcones and aurones previously synthetized in our laboratory. The experimental lipophilicity data have been compared with theoretical lipophilicity parameters estimated by various computational methods. Good correlations between the experimental and calculated lipophilicity parameters have been found for both investigated classes of compounds. Correlations between the lipophilicity of the thiazole chalcones and aurones and their antiproliferative activity were discussed. The methodologies and data gathered in this study will contribute to the lipophilicity studies of chalcones and aurones derivatives, two important classes of compounds in medicinal chemistry.

Model development for predicting in vitro bio-capacity of green rooibos extract based on composition for application as screening tool in quality control.

Mounting evidence of the ability of aspalathin to target underlying metabolic dysfunction relevant to the development or progression of obesity and type 2 diabetes created a market for green rooibos extract as a functional food ingredient. Aspalathin is the obvious choice as a chemical marker for extract standardisation and quality control, however, often the concentration of a single constituent of a complex mixture such as a plant extract is not directly related to its bio-capacity, i.e. the level of in vitro bioactivity effected in a cell system at a fixed concentration. Three solvents (hot water and two EtOH-water mixtures), previously shown to produce bioactive green rooibos extracts, were selected for extraction of different batches of rooibos plant material (n = 10). Bio-capacity of the extracts, tested at 10 µg ml-1, was evaluated in terms of glucose uptake by C2C12 and C3A cells and lipid accumulation in 3T3-L1 cells. The different solvents and inter-batch plant variation delivered extracts ranging in aspalathin content from 54.1 to 213.8 g kg-1. The extracts were further characterised in terms of other major flavonoids (n = 10) and an enolic phenylpyruvic acid glucoside, using HPLC-DAD. The 80% EtOH-water extracts, with the highest mean aspalathin content (170.9 g kg-1), had the highest mean bio-capacity in the respective assays. Despite this, no significant (P≥ 0.05) correlation existed between aspalathin content and bio-capacity, while the orientin, isoorientin and vitexin content correlated moderately (r≥ 0.487; P < 0.05) with increased glucose uptake by C2C12 cells. Various multivariate analysis methods were then applied with Evolution Program-Partial Least Squares (EP-PLS) resulting in models with the best predictive power. These EP-PLS models, based on all quantified compounds, predicted the bio-capacity of the extracts for the respective cell types with RMSECV values ≤ 11.5, confirming that a complement of compounds, and not aspalathin content alone, is needed to predict the in vitro bio-capacity of green rooibos extracts. Additionally, the composition of hot water infusions of different production batches of green rooibos (n = 29) at 'cup-of-tea' equivalence was determined to relate dietary supplementation with the extract to intake in the form of herbal tea.

Quantitation of dietary dihydrochalcones in Indian crabapple (Malus sikkimensis) using validated high-performance liquid chromatography.

In the present study, a systematic validated method was developed for the determination of two key dietary dihydrochalcones (DHC) viz. phloridzin (PZ) and phloretin (PT) in the leaves of Sikkim crabapple (Malus sikkimensis) using HPLC-Photo Diode Array (PDA). Chromatographic separation was optimized on a C18 column using a gradient elution of water/acetonitrile with the flow rate of 1.0 mL/min at 25°C at 280 nm. Sample preparation approach is rapid and energy efficient, and it requires no pre-concentration before analysis. Validation showed a good analytical performance in terms of specificity, linearity (r2 > 0.999), precision (% RSD < 1.08), recovery (97-100.4%) and sensitivities (limits of detection: 12.48 and 14.95 ng/mL; limit of quantification: 41.61 and 49.85 ng/mL) of PZ and PT, respectively. Developed approach was employed for targeted phytochemical analysis in the bark and fruits of M. sikkimensis. The PZ content in the bark and leaves was highest (12-13 mg/100 mg), about 90-fold higher than fruits. PT was only present in the leaves (0.57 mg/100 mg). The comparative data on PZ and PT content in various wild apple species/cultivar from different countries have also been discussed. The reliability of the validated method was established by analyzing global and expanded uncertainties in two DHC determinations in wild apple. The present method fulfills the technical requirement of ISO 17025:2017 for quality control of M. sikkimensis.

Classification of edible chrysanthemums based on phenolic profiles and mechanisms underlying the protective effects of characteristic phenolics on oxidatively damaged erythrocyte.

In this study, phenolic profiles of chrysanthemums derived from five main species were determined for characterization of rationality of their application in tea, beverages and functional foods. A total of 41 phenolics including 3 phenolic acids, 17 flavones, 9 flavanones, 1 dihydroflavonol, 4 flavonols, 4 chalcones and 3 aurones were identified. The contents of 22 characteristic phenolics were simultaneously determined. Chrysanthemum morifolium cv. 'Qiju' (with abundant phenolics) and Coreopsis tinctoria Nutt. (with unique and abundant flavonoid aglycones and glycosides), exhibited excellent cellular antioxidant activities and strong market potentials. Chlorogenic acid, 3,5-dicaffeoylquinic acid and luteolin-7-O-glucoside largely contributing to cellular antioxidant activity of 'Qiju' by forming protective membrane around erythrocyte should be markers for quality control of 'Qiju'. Okanin, the gut microbial-produced metabolite of marein, possessed strong protective effect on oxidatively damaged erythrocyte via incorporating in membrane and entering cytoplasm. Okanin and marein should be markers for quality control of C. tinctoria.

Virtual and experimental screening of phenylfuranchalcones as potential anti-Leishmania candidates.

Discovery of novel or repurposed chemical treatments for leishmaniasis is a priority given the limited number of therapeutic alternatives available. One way to accelerate the finding is by implementing virtual screening methodologies using structural information, with subsequent experimental validations. Here we tested a library of 48 phenylfuranchalcones as anti-Leishmania agents that can be associated to the potential inhibition of a protein target within the parasite. For that purpose, a list of 43 protein structures from different Leishmania species was prepared to dock the virtual compound library. The protein with the best predicted scores was used as reference to select a subset of previously synthesized compounds for in vitro validation of their cytotoxicity and anti-Leishmania activity. We found a set of active compounds (EC50 < 25 µM) that were compared with the computational results using Spearman correlations. The analysis allowed us to propose the inhibition of a phosphodiesterase enzyme as the potential mechanism of action.

[Analysis of flavonoids in Coreopsis tinctoria by integrating 2D-TLC and HPLC-IT-TOF-MS].

The qualitative analysis of flavonoids in Coreopsis tinctoria was carried out by a combination of 2 D-TLC and HPLC-IT-TOF-MS. The separation was conducted on 2 D-TLC and a Phenomenex Kinetex Evo C_(18) column(2.1 mm×100 mm, 2.6 µm) with methanol-0.05% aqueous formic acid by gradient elution. Electrospray ionization-(ESI) source was applied and operated in both positive and negative ionization modes. Eighteen flavonoids including three flavonoids, one flavonol, nine flavonones, one flavanonol and four chalcones, were putatively identified from the flavone-enriched fraction of C. tinctoria. 2 D-TLC could separate the flavonoids from C. tinctoria. HPLC-IT-TOF-MS was able to quickly and accurately analyze the flavonoids in C. tinctoria. The results would provide experimental information for the efficacy material basis clarification of C. tinctoria.

Visualization of Aspalathin in Rooibos (Aspalathus linearis) Plant and Herbal Tea Extracts Using Thin-Layer Chromatography.

Aspalathin, the main polyphenol of rooibos (Aspalathus linearis), is associated with diverse health promoting properties of the tea. During fermentation, aspalathin is oxidized and concentrations are significantly reduced. Standardized methods for quality control of rooibos products do not investigate aspalathin, since current techniques of aspalathin detection require expensive equipment and expertise. Here, we describe a simple and fast thin-layer chromatography (TLC) method that can reproducibly visualize aspalathin in rooibos herbal tea and plant extracts at a limit of detection (LOD) equal to 178.7 ng and a limit of quantification (LOQ) equal to 541.6 ng. Aspalathin is a rare compound, so far only found in A. linearis and its (rare) sister species A. pendula. Therefore, aspalathin could serve as a marker compound for authentication and quality control of rooibos products, and the described TLC method represents a cost-effective approach for high-throughput screening of plant and herbal tea extracts.

Enrichment of total flavones and licochalcone A from licorice residues and its hypoglycemic activity.

Industrial processing of glycyrrhizic leads to a lot of residues which are usually threw away randomly or used as feed. Therefore, the purpose of this study was to study licorice residues as a source of bioactive compounds with potentially applications. In this study, the enrichment and purification of total flavones from the licorice residues was achieved by using macroporous resins. The performances and separation characteristics of four selected macroporous resins with different chemical and physical properties were investigated. HPD-100 resin was the most effective, the content of total flavones increased from 50.94% in the original extract to 82.98% in the 80% ethanol fraction (a 1.63-fold increase). Further purification treatment by polyamide resin, licochalcone A with a purity of 80.28% was obtained in a 45% ethanol fraction, and a higher purity (>85%) of licochalcone A can be obtained by single crystallization operation. And hypoglycemic effect of the total flavones from licorice residues on high fat diet and STZ induced diabetic c57 mice was preliminary investigated. The results showed: the fasting blood glucose of mice in the low and medium dose total flavones group decreased significantly. The proposed technique is uncomplicated, easily managed, cost-effective, and environmentally friendly and is proper for both large-scale licorice residues application and waste management.

Licochalcone B Extracted from Glycyrrhiza uralensis Fisch Induces Apoptotic Effects in Human Hepatoma Cell HepG2.

The present study explored the molecular mechanism by which licochalcone B induces the cell cycle arrest and apoptosis in human hepatoma cell HepG2. Initial extraction and identification were performed by HPLC, UPLC-TOF-MS/MS, and NMR analysis, respectively. Licochalcone B inhibited the HepG2 growth with IC50 (110.15 µM) after 24 h, caused morphological distortion, and seized the cell cycle in the G2/M phase (cell arrest in G2/M:43.1 ± 2.2% for 120 µM versus 23.7 ± 1.2% for control), as well as induced apoptosis and intracellular ROS generation. Furthermore, exposure to licochalcone B markedly affected the cell cycle (up/down regulation) at mRNA and protein levels. Apoptosis was induced through the activation of receptor-mediated and mitochondrial pathways. The inhibition of Caspase 8 and Caspase 9 proteins abolished the licochalcone B induced apoptosis. The present work suggested that licochalcone B may further be identified as a potent functional food component with specific health benefits.