Approach to the study of C-glycosyl flavones acylated with aliphatic and aromatic acids from Spergularia rubra by high-performance liquid chromatography-photodiode array detection/electrospray ionization multi-stage mass spectrometry

Prinsepia utilis Royle leaf extract: Ameliorative effects on allergic inflammation and skin lesions in allergic contact dermatitis and polyphenolic profiling through UPLC-MS/MS coupled to chemometric analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Allergic contact dermatitis (ACD) is a common allergic inflammatory disease that is concomitant with skin swelling, redness, dry itching, and relapses. Prinsepia utilis Royle, a Chinese and Indian folk medicine, is rich in polyphenols with potential anti-inflammatory and skin-protective activities. However, the underlying mechanism of P. utilis leaf (PUL) in the treatment of ACD and its functional basis remains unclear.

AIM OF THE STUDY

This study is aimed to explore and reveal the active substances and mechanism of PUL against ACD.

MATERIALS AND METHODS

Hyaluronidase inhibitory assay and fluorescein isothiocyanate (FITC)-induced ACD mouse model were performed to assess the antiallergic effects of PUL in vitro and in vivo. Different solvents were applied to obtain multiple PUL extracts. The extracts were further tested for total phenolic content (TPC) and total flavonoid content (TFC) by using spectrophotometric assays. Polyphenolic profiles were analyzed by using ultrahigh-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-QTOF-MS/MS), and a simultaneous quantification method was established using UPLC-QTrap-MS/MS through multiple reaction monitoring (MRM) and applied to analyze the pharmacokinetics of the multiple major polyphenols of PUL in mice.

RESULTS

The water extract of PUL with the highest TPC/TFC exhibited the strongest antihyaluronidase effect (IC₅₀ = 231.93 μg/mL). In vivo assays indicated that the oral administration of PUL water extract dose-dependently attenuated ACD-like symptoms by decreased interleukin (IL)-4, IL-5, IL-13, IL-33, thymic stromal lymphopoietin, and IgE production, suppressed eosinophil and basophil secretion, and increasing the expression of tight junction (TJ) proteins (claudin-1 [CLDN-1] and occludin). Concomitantly, UPLC-QTOF-MS/MS analysis enabled the identification of 60 polyphenols and the pharmacokinetic parameters of seven quantified constituents of PUL were characterized. Four compounds, trans-p-coumaric acid 4-O-β-D-glucopyranoside (11), vicenin-2 (21), isoschaftoside (31), and kaempferol 3-O-(2″,6″-di-O-α-L-rhamnopyransoyl)-β-D-glucopyranoside (38) which displayed satisfactory pharmacokinetic features, were considered as potential effective substances in PUL.

CONCLUSIONS

PUL water extract ameliorated the allergic inflammation of ACD by repairing the epithelial barrier and alleviating Th2-type allergic inflammation. The anti-allergic effect of PUL is closely related to its phenolic substances, and compounds 11, 21, 31, and 38 were the active substances of PUL. It revealed that P. utilis could be developed as a new source of antiallergic agents for ACD therapy.

UHPLC-MS Phytochemical Profiling and Insight into Bioactivity of Rabelera holostea (Greater Stitchwort) Extract

Rabelera holostea (L.) M. T. Sharples & E. A. Tripp (Greater Stitchwort), formerly known as Stellaria holostea L., is widespread in the warm temperate areas of Europe and Western Asia, the Caucasus region, as well as in some countries of North Africa. Nowadays it is considered as a weed, but earlier it was often used raw in salads or for the treatment of various inflammatory disorders. The goal of this study was to determine the constituents of the methanol extract of R. holostea aerial parts and its biological potential in terms of antioxidant, antimicrobial, and anti-inflammatory properties. Until now, the constituents and biological activities of this plant were not reported in detail. A comprehensive phytochemical profiling of the extract has shown that phenolic acids, such as ferulic, chlorogenic, and p-coumaric acid, flavonoids and flavonoid glucosides, such as chrysoeriol, rutin, and naringin, are the most abundant compounds. The antioxidant activity of R. holostea extract towards DPPH and ABTS radicals, but also the total antioxidant capacity and the inhibition of lipid peroxidation were moderate. The antimicrobial potential was pronounced mostly towards some fungi such as F. oxysporum (MIC 1.25 mg/mL), whereas the capacity of R. holostea to affect the growth of bacteria was much less pronounced. R. holostea extract was most inclined to anti-inflammatory activity. At a concentration of 50 µg/mL, it significantly inhibited both cyclooxygenase enzymes (COX-1 and COX-2) by 71.24% and 72.83%, respectively. Molecular docking studies indicated that chlorogenic acid and chrysoeriol are the main contributors to COX-1 and COX-2 inhibitory activity.

Costus spiralis extract restores kidney function in cisplatin-induced nephrotoxicity model: Ethnopharmacological use, chemical and toxicological investigation

ETHNOPHARMACOLOGICAL RELEVANCE

Costus spiralis (Jacq.). Roscoe (Costaceae) is traditionally used in Brazil for the treatment of kidney diseases such as pyelonephritis, urethra inflammation, kidney stones, and inflammatory conditions. There are reports of its use by Brazilian Indians since the 17th century when it was known as "pacocatinga." Currently, the use of the Costus species in Brazil is widespread, which was evidenced by the inclusion of the genus in the Brazilian National List of Medicinal Plants of Interest to the Unified Health System (RENISUS).

AIM OF THE STUDY

This study aimed to confirm the ethnopharmacological use of Costus spiralis in the treatment of kidney diseases, toxicity study using animal models, and the phytochemistry of the species.

MATERIALS AND METHODS

The chemical profile of Costus spiralis leaves extract (CSLE) was obtained for the hydroethanolic extract by ultra-performance liquid chromatography coupled to a mass spectrometer and ultraviolet detector with diode array (UPLC-UV/DAD-ESI-MS). The acute oral toxicity of the extract was predicted using the neutral red uptake cytotoxicity assay. Wistar rats were used in a model in vivo for confirmation of acute oral toxicity (2000 mg/kg p.o. for 14 days.) and determination of the effect on a cisplatin-induced nephrotoxicity model.

RESULTS

The analysis by UPLC-UV/DAD-ESI-MS showed that the chemical composition of the extract is mostly di-glycosylated flavones of apigenin. In the extract were identified the flavones vicenin II and schaftoside. The quantification of total flavonoids by spectrometry showed 0.880%. CSLE proved to be safe for acute oral administration (2000 mg/kg) with an IC₅₀ value of 222.9 μg/mL and predicted oral toxic dose of 523.82 μg/mL in a neutral red uptake cytotoxicity assay. The absence of death allows the classification of the extract in class 5 according to OECD 423 guidelines and therefore it can be considered as a high acute safety product, which is highly relevant, considering the wide popular use of the species. In the cisplatin-induced nephrotoxicity model, C. spiralis extract (5, 15, and 30 mg/kg) significantly improved renal function, reversing almost completely the effects on plasma creatinine levels and creatinine clearance (p < 0.001).

CONCLUSIONS

This study demonstrates that oral administration of Costus spiralis extract leaves is safe and effective in restoring the renal function in rats in a cisplatin-induced nephrotoxicity. It is suggested that the observed activity is related to the flavonoids present. This hypothesis should be confirmed, and the participation of other secondary metabolites should be investigated in the future.

Determination of Flavonoids in Selected Scleranthus Species and Their Anti-Collagenase and Antioxidant Potential

A new 5,7-dihydroxy-3′-methoxy-4′-acetoxyflavone-8-C-β-d-arabinopyranoside-2″-O-(4‴-acetoxy)-glucoside (6) and three known flavone C-glycosides—5,7,3′,4′-tetrahydroxyflavone-6-C-xyloside-8-C-β-d-glucoside (lucenin-1) (7), 5,7,3′-trihydroxyflavone-6-C-glucoside-8-C-β-d-glucoside (vicenin-2) (8), and 5,7,4′-trihydroxy-3′-methoxyflavone-6-C-β-d-glucopyranoside-8-C-α-arabinopyranoside (chrysoeriol-6-C-β-d-glucopyranoside-8-C-α-arabinopyranoside) (9)—were isolated from aerial parts of Scleranthus perennis L. (Caryophyllaceae). Their structures were determined through the use of comprehensive spectroscopic and spectrometric methods, and a method for the quantification of the major constituents of S. perennis and S. annuus L. was developed. Furthermore, the anti-collagenase and antioxidant activities of all isolated compounds obtained from extracts and fractions from both Scleranthus species were evaluated. The highest percentage of collagenase inhibition (at 400 µg/mL) was distinguished for methanolic extracts (22.06%, 32.04%) and ethyl acetate fractions (16.59%, 14.40%) from S. annuus and S. perennis. Compounds 6–9 displayed moderate inhibitory activity, with IC₅₀ values ranging from 39.59–73.86 µM.

Phytochemical characterisation of Phlomis linearis Boiss. & Bal and screening for anticholinesterase, antiamylase, antimicrobial, and cytotoxic properties

In the present work, essential oil and fatty acids and extracts obtained from aerial parts of Phlomis linearis Boiss. & Bal. were investigated for chemical composition and biological activities. The phytochemical analyses were conducted with gas chromatography-mass spectrometry/flame ionisation detector (GC-MS/FID) and liquid chromatography-mass spectromtetry (LC-MS/MS) techniques. The extracts and essential oil were studied for α-amylase and acetylcholinesterase activities with two different spectrophotometric methods. Antimicrobial activities of the extracts were investigated by microdilution. The extracts were evaluated in vitro for cytotoxic effects against cancer and normal cell lines by MTT assay. The essential oil (EO) contained α-pinene (12.5%) and β-caryophyllene (10.7%) as main compounds. Palmitic (26.5%) and nonadecanoic acids (26.6%) were determined as fatty acids. Phytochemical analysis of the extracts found phenolic acids, phlinosides, verbascoside, and flavonoids. The extracts and essential oil demonstrated poor α-amylase inhibitory activity. The best acetylcholinesterase inhibitory activity was obtained for diethly ether extract of P. linearis (67.2 ± 3.4%) at 10 mg /mL concentration. Ethyl acetate extract found to be effective against Staphlococcus aureus at a minimum inhibitory concentration (MIC) of 156.26 µg/mL. Diethyl ether extract of P. linearis was active on A549 cell lines with an IC50 = 316 ± 4.16 µg/mL when compared with cisplatin IC50 = 24.43 ± 0.14 µg/mL. To the best of our knowledge, the present work is the first comprehensive report on anti-acetylcholinesterase, anti-α-amylase, and antimicrobial activities, as well as cytotoxic effects of P. linearis.

Valorization of Heat-Treated Brewers' Spent Grain Through the Identification of Bioactive Phenolics by UPLC-PDA and Evaluation of Their Antioxidant Activities

Thermal processing not only disrupts cell membranes and cell walls, but also cleaves covalent bonds releasing low molecular phenolic. This study examined the impact of various heat treatments (100, 140, and 160°C) on the composition of phenolic acids and antioxidant activities in extracts obtained from defatted brewers spent grain (BSG) meal. Heating BSG at 160°C resulted in a 2-fold increase in total phenolic content [TPC, 172.98 ± 7.3 mg Gallic acid equivalent (GAE)/100 g defatted meal] and total flavonoid content [TFC, 16.15 ± 2.22 catechin equivalents (CE)/100 g defatted meal] compared to the untreated BSG extracts. The antioxidant activities of treated BSG extracts, determined by radical scavenging and ferric reducing antioxidant power (FRAP) were significantly (p < 0.5) higher than the corresponding untreated BSG extracts. Eleven phenolic acids were identified and quantified in BSG extracts by Ultra Performance Liquid Chromatography with Photodiode Array (UPLC-PDA). The amounts varied significantly (p < 0.05) depending on the degree of toasting BSG was subjected to. Chlorogenic acid, an ester of caffeic and quinic acid was the predominant phenolic acid present in all fractions. Significant (p < 0.05) increases in TPC, TFC, individual phenolic acids and antioxidant activity were observed in BSG extracts exposed to increasing oven temperatures. These results confirm the ability of heat processing to release bioactive phenolic from their bound forms thereby enhancing the phenolic acids and the digestibility of BSG meal in the intestinal tract.

Identification of C-glycosyl flavones and quality assessment in Dendrobium nobile

RATIONALE

Flavones are significant indicators of quality in traditional Chinese medicines (TCMs) and thus play a significant role in the quality control of TCMs in the pharmaceutical industry. Most flavones in Dendrobium nobile Lindl, a TCM with a long cultivation history and rich sources, have not been identified. This study was aimed at identifying the flavones in D. nobile from various habitats.

METHODS

High-performance liquid chromatography (HPLC) coupled with diode-array detection and HPLC multiple-stage tandem mass spectrometry was used to identify the chemical constituents of D. nobile from various habitats, and a method was established to determine the content of vicenin II, violanthin and isoviolanthin. Hierarchical cluster analysis, principal component analysis and orthogonal partial least-squares discriminant analysis were used to analyze the variations among 26 batches from different habitats.

RESULTS

A total of 33 flavones were tentatively identified. Twenty-five flavones, previously undescribed in D. nobile, were acylated by p-coumaroyl, feruloyl, sinapoyl or 3-hydroxy-3-methylglutaryl. The D. nobile habitats were distinguished by significant differences in their flavone content. The C-glycosyl flavones were demonstrated to be characteristic compounds for evaluating D. nobile from various habitats. In particular, flavones acylated with 3-hydroxy-3-methylglutaryl were specific compounds that were only detected in samples from Yunnan.

CONCLUSIONS

The results of this study could be used to improve the quality control of D. nobile and could provide references for the identification of acylated C-glycosyl flavones in other natural products.

Detection of flavone C-glycosides in the extracts from the bark of Prunus avium L. and Prunus cerasus L

The extracts from the bark of Prunus avium and Prunus cerasus have been analyzed by using high pressure liquid chromatography/electrospray ionization mass spectrometry. For the first time in the bark of Prunus species flavonoid C-glycosides have been detected. On the basis of the characteristic fragmentation patterns of their [M-H]^- and [M + H]⁺ ions, three flavonoid C-glycosides have been identified, namely apigenin-6,8-di-C-glucoside (vicenin-2), apigenin-6-C-glucoside (isovitexin) and chrysin-8-C-glucoside. Taking into account the widely studied biological activities of flavonoid C-glycosides, the barks of these common fruit trees seem to be interesting materials of potential medical or cosmetic application.

HPLC coupled with electrospray ionization multistage MS/MS and TLC analysis of flavones-C-glycosides and bibenzyl of Dendrobium hercoglossum

Dendrobium hercoglossum Rchb. f. (D. hercoglossum), as one of the origins of medicinal Dendrobium, has been widely used as a health food and nutrient source promoting fluid production. Due to a lack of quality control, it is often counterfeited or mixed with other Dendrobium. In this study, a high-performance liquid chromatography characteristic chromatogram method is established for the quality evaluation of D. hercoglossum. Based on the high-performance liquid chromatography characteristic chromatogram, D. hercoglossum is divided into two classes, each with different flavone peaks. These flavone peaks were identified using high-performance liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry. Among them, the acylated (3-hydroxy-3-methylglutaryl, p-coumaroyl, feruloyl, or sinapoyl) flavones-C-glycosides are first found in D. hercoglossum in this study. In addition, one unique band was found in D. hercoglossum by thin-layer chromatography, which can be used to distinguish it from other Dendrobium species as a characteristic marker of this plant. Combining the high-performance liquid chromatography characteristic chromatogram and high-performance liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry, the unique band was identified as 4,5-dihydroxy-3,3'-dimethoxybibenzyl. These analysis methods can be applied for the quality control and identification of D. hercoglossum as well as providing reference for the identification of similar constituents in other Dendrobium species.

Characterization of Extra Early Spanish Clementine Varieties (Citrus clementina Hort ex Tan) as a Relevant Source of Bioactive Compounds with Antioxidant Activity

The most relevant nutrients and bioactive compounds (soluble sugars, dietary fiber, ascorbic acid and organic acids, individual phenolic compounds, fatty acids, and tocopherols) as well as antioxidant activity have been characterized in three extra early varieties of clementine (Citrus clementina Hort ex Tan. Basol, Clemensoon and Clemenrubí) cultivated in Valencia (Spain). Clementines are a relevant source of bioactive compounds, such as vitamin C (values around 80 mg/100 g), allowing to satisfy the recommended daily intake with the consumption of a normal portion. Sucrose was the most abundant sugar, and potassium the main mineral while manganese was the least. Fat content was very low (<0.5 mg/100 g), with palmitic acid and α-tocopherol the most abundant fatty acid and vitamin E form, respectively. Flavonoids were the predominant phenolic compounds, with narirutin/naringin and (neo)hesperidin the best represented ones. The antioxidant capacity evaluated by reducing power, DPPH, and β-carotene bleaching inhibition assays was satisfactory with values similar to those reported in other citrus fruits. Thus, this fruit is a relevant source of bioactive compounds with antioxidant properties of interest for consumers and the food industry.

Reinvestigation of Herniaria glabra L. saponins and their biological activity

Twelve undescribed triterpenoid pentacyclic glycosides, medicagenic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[α-L-rhamnopyranosyl-(1 → 2)]-[β-D-apiofuranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[α-L-rhamnopyranosyl-(1 → 2)]-3,4-O-diacetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[2-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[3-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[4-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[β-D-glucopyranosyl-(1 → 2)]-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid), zanhic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}2β,3β,16α-trihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-β-D-fucopyranosyl-(1→)}-2β,3β,16α-trihydroxyolean-12-ene-23,28-dioic acid), 29-hydroxy-medicagenic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β,29β-trihydroxyolean-12-ene-23,28-dioic acid) and herniaric acid (28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-18-ene-23,28-dioic acid) were isolated from the whole plant extract of Herniaria glabra L. (Caryophyllaceae), wild growing in the Ukraine. In addition, five known triterpenoid saponins; i.e. herniariasaponins 1, 4, 5, 6, and 7 were also isolated. Their structures were elucidated by HRESIMS, 1D and 2D NMR spectroscopy, as well as by comparison with the literature data. Twelve herniariasaponins, the purified crude extract, and the saponin fraction were evaluated in vitro for their xanthine oxidase, collagenase, elastase, and tyrosinase inhibitory activity. Moreover, herniariasaponins 4, 5, and 7 were screened for their cholinesterase inhibitory potential. As a result, no or low inhibition towards the mentioned enzymes was observed.

Identification of C-glycosyl flavones by high performance liquid chromatography electrospray ionization mass spectrometry and quantification of five main C-glycosyl flavones in Flickingeria fimbriata

Flickingeria fimbriata is commonly applied in China as a traditional Chinese medicine (TCM), however the quality control of it is incomplete. In this work, we aim to identify and quantify the structures of C-glycosyl flavones in F. fimbriata. High performance liquid chromatography-diode array detector (HPLC-DAD) and High performance liquid chromatography–electrospray ionization–multiple stage tandem mass spectrometry (HPLC–ESI–MSⁿ) methods were combined to identify C-glycosyl flavones and determine their contents. Twenty acylated C-glycosyl flavones and ten non-acylated C-glycosyl flavones were identified for the first time in F. fimbriata on systematic MSⁿ analysis via HPLC–ESI–MSⁿ. The aglycones of all of these compounds were apigenin or chrysoeriol and were acylated with p-coumaric, ferulic, 3,4-dimethoxycinnamic or 3,4,5-trimethoxycinnamic acids. Furthermore, the quantification result suggest that two C-glycosyl flavones (vicenin-I and vicenin-III) with relative high contents were revealed to be more strongly acylated in F. fimbriata. The method is sufficiently precise, accurate, and sensitive for the qualitative and quantitative analysis of C-glycosyl flavones, which is expected to establish a standard for quality control and identification in this plant.

Nutritional, chemical and bioactive profiles of different parts of a Portuguese common fig (Ficus carica L.) variety

This study aims to give an unprecedented contribution on the chemical composition and bioactivities of the most produced and appreciated Portuguese fig variety ("Pingo de Mel") with the view of expanding the knowledge on its potentialities. An advanced characterization of its peel and pulp parts was carried out. Four free sugars (glucose, fructose, trehalose and sucrose), 5 organic acids (oxalic, quinic, malic, citric, and succinic acids), tocopherols in all their 4 forms, besides 23 fatty acids were detected in the samples. Fifteen different phenolic components were found in the peel hydroethanolic extract; whereas 12 were detected in the pulp hydroethanolic extract. Quercetin-3-O-rutinoside (rutin) was the major constituent of the peel, accounting for 33.8% of its phenolic content, followed by 5-O-caffeoylquinic acid and vanillic acid malonyl di-deoxyhexoside. Caffeic acid derivatives, such as caffeic acid hexosides, were the major components of pulp, followed by vanillic acid derivatives and O-caffeoylquinic acid. Both extracts displayed promising antioxidant capacities in all methods used, namely the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging, the reducing power, the inhibition of β-carotene bleaching assays, the thiobarbituric acid reactive substances assay and the oxidative haemolysis inhibition assay; however, the peel presented significantly lower IC₅₀ values than pulp. The extracts showed practically identical antibacterial capacities, being effective against methicillin-sensitive Staphylococcus aureus (MICs = 2.5 mg/mL), besides methicillin-resistant S. aureus, Escherichia coli and Morganella morganii (MICs = 5 mg/mL). The obtained results evidence that the fig peel is superior to the corresponding pulp as it relates to nutritional and phenolic profiles as well as bioactivities, endorsing the urgency in valorising and exploiting this usually discarded industrial by-product.

Scabiosa stellata L. Phenolic Content Clarifies Its Antioxidant Activity

The phenolic profile of Scabiosa stellata L., a species used in Moroccan traditional medicine, is disclosed. To obtain that profile the species extract was analyzed by ultra-high-performance chromatography coupled to photodiode-array detection and electrospray ionization/ion trap mass spectrometry (UHPLC-DAD-ESI/MSn). Twenty-five phenolic compounds were identified from which isoorientin and 4-O-caffeoylquinic acid can be highlighted because they are the major ones. The antioxidant activity was significantly controlled by the fraction type, with the n-butanol fraction showing the highest antioxidant activity (FRS50 = 64.46 µg/mL in the DPPH assay, FRS50 = 27.87 µg/mL in the ABTS assay and EC50 = 161.11 µg/mL in the reducing power assay). A phytochemical study of the n-butanol fraction was performed, and some important flavone glycosides were isolated. Among them the tamarixetin derivatives-the less common ones-can be emphasized. This phytochemical study and polyphenolic profile can be correlated with S. stellata extracts in vitro antioxidant activity. Moreover, it can be regarded as an evidence of its medicinal use and can incentivize its consumption.

Chemical findings and in vitro biological studies to uphold the use of Ficus exasperata Vahl leaf and stem bark

Ficus exasperata Vahl, commonly known as sandpaper, is a terrestrial Afro-tropical tree used in popular medicine. Despite the existence of some works on the biological activities of this species, its chemical composition is still poorly known. The aim of this study was to extend the knowledge on the phytochemistry and biological properties of this species. Aqueous extracts from F. exasperata leaves and stem bark were analysed. Thirty-one phenolic compounds, comprising cinnamoyl derivatives, flavonoid-O-glycosides, flavonoid-mono-C-glycosides, flavonoid-di-C-glycosides and one furanocoumarin, were determined by HPLC-DAD-ESI/MSⁿ and UPLC-ESI-QTOF-MS, 26 of them being reported for the first time in this species. The profile of organic acids, characterized by HPLC-UV, was also reported for the first time. The best radical scavenging activity was observed for the aqueous extract from leaves (IC₅₀ values of 222.5, 510.0 and 50.0 μg/mL against DPPH^•, ^•NO and O₂^•-, respectively). In addition, both aqueous extracts of the leaves and stem bark displayed a weak effect on α-amylase, and no cytotoxicity against gastric adenocarcinoma cell line, AGS. This study contributes to the valorisation of these vegetal materials, which may have application in functional foods and/or nutraceuticals.

Identification and quantification of flavonoids in yellow grain mutant of rice (Oryza sativa L.)

Flavonoids are naturally occurring phenolic compounds with potential health-promoting activities. Although anthocyanins and phenolic acids in coloured rice have been investigated, few studies have focused on flavonoids. Herein, we analysed flavonoids in a yellow grain rice mutant using UHPLC-DAD-ESI-Q-TOF-MS, and identified 19 flavonoids by comparing retention times and accurate mass measurements. Among them, six flavonoids, isoorientin, isoorientin 2″-O-glucoside, vitexin 2″-O-glucoside, isovitexin, isoscoparin 2″-O-glucoside and isoscoparin, were isolated and fully identified from the yellow grain rice mutant, and the levels were significantly higher than wild-type, with isoorientin particularly abundant in mutant embryo. Significant differences in total phenolic compounds and antioxidant activity were observed in mutant rice by DPPH, FRAP and TEAC assays. The results suggest that the representative six flavonoids may play an important role in colouration and antioxidant activity of embryo and endosperm tissue. The findings provide insight into flavonoid biosynthesis and the possibility of improving functionality in rice.

Comprehensive characterization of C-glycosyl flavones in wheat (Triticum aestivum L.) germ using UPLC-PDA-ESI/HRMSn and mass defect filtering

A comprehensive characterization of C-glycosyl flavones in wheat germ has been conducted using multi-stage high resolution mass spectrometry (HRMSn ) in combination with a mass defect filtering (MDF) technique. MDF performed the initial search of raw data with defined C-glycosyl flavone mass windows and mass defect windows to generate the noise-reduced data focusing on targeted flavonoids. The high specificity of the exact mass measurement permits the unambiguous discrimination of acyl groups (nominal masses of 146, 162 and 176.) from sugar moieties (rhamnose, glucose or galactose and glucuronic acid). A total of 72 flavone C-glycosyl derivatives, including 2 mono-C-glycosides, 34 di-C-glycosides, 15 tri-glycosides, 14 acyl di-C-glycosides and 7 acyl tri-glycosides, were characterized in wheat germ, some of which were considered to be important marker compounds for differentiation of whole grain and refined wheat products. The 7 acylated mono-O-glycosyl-di-C-glycosyl flavones and some acylated di-C-glycosyl flavones are reported in wheat for the first time. The frequent occurrence of numerous isomers is a remarkable feature of wheat germ flavones. Both UV and mass spectra are needed to maximize the structure information obtained for data interpretation. Copyright © 2016 John Wiley & Sons, Ltd.

Current Advances in the Metabolomics Study on Lotus Seeds

Lotus (Nelumbo nucifera), which is distributed widely throughout Asia, Australia and North America, is an aquatic perennial that has been cultivated for over 2,000 years. It is very stimulating that almost all parts of lotus have been consumed as vegetable as well as food, especially the seeds. Except for the nutritive values of lotus, there has been increasing interest in its potential as functional food due to its rich secondary metabolites, such as flavonoids and alkaloids. Not only have these metabolites greatly contributed to the biological process of lotus seeds, but also have been reported to possess multiple health-promoting effects, including antioxidant, anti-amnesic, anti-inflammatory, and anti-tumor activities. Thus, comprehensive metabolomic profiling of these metabolites is of key importance to help understand their biological activities, and other chemical biology features. In this context, this review will provide an update on the current technological platforms, and workflow associated with metabolomic studies on lotus seeds, as well as insights into the application of metabolomics for the improvement of food safety and quality, assisting breeding, and promotion of the study of metabolism and pharmacokinetics of lotus seeds; meanwhile it will also help explore new perspectives and outline future challenges in this fast-growing research subject.

Rapid Identification and Assignation of the Active Ingredients in Fufang Banbianlian Injection Using HPLC-DAD-ESI-IT-TOF-MS

Fufang Banbianlian Injection (FBI) is a well-known traditional Chinese medicine formula composed of three herbal medicines. However, the systematic investigation on its chemical components has not been reported yet. In this study, a high-performance liquid chromatography combined with diode-array detector, and coupled to an electrospray ionization with ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method, was established for the identification of chemical profile in FBI. Sixty-six major constituents (14 phenolic acids, 14 iridoids, 20 flavonoids, 2 benzylideneacetone compounds, 3 phenylethanoid glycosides, 1 coumarin, 1 lignan, 3 nucleosides, 1 amino acids, 1 monosaccharides, 2 oligosaccharides, 3 alduronic acids and citric acid) were identified or tentatively characterized by comparing their retention times and MS spectra with those of standards or literature data. Finally, all constituents were further assigned in the individual herbs (InHs), although some of them were from multiple InHs. As a result, 11 compounds were from Lobelia chinensis Lour, 33 compounds were from Scutellaria barbata D. Don and 38 compounds were from Hedyotis diffusa Willd. In conclusion, the developed HPLC-DAD-ESI-IT-TOF-MS method is a rapid and efficient technique for analysis of FBI sample, and could be a valuable method for the further study on the quality control of the FBI.

Chemical characterization and bioactive properties of Geranium molle L.: from the plant to the most active extract and its phytochemicals

After a period of indifference, in which synthetic compounds were favored, there is an increasing interest in the study of the biological properties of plants and the active principles responsible for their therapeutic properties. Geranium molle L. has been used in the Portuguese folk medicine for the treatment of various ailments including cancer but, unlike many of the species from the Geranium genus, its phytochemical characterization and biological activity are virtually unexplored. In this study a G. molle sample from Trás-os-Montes, north-eastern Portugal, was chemically characterized regarding nutritional value, free sugars, organic acids, fatty acids and tocopherols, and several aqueous (decoction, infusion) and organic (n-hexane, dichloromethane, ethyl acetate, acetone, methanol) extracts of the plant were assessed for their bioactive properties. The antioxidant activity was evaluated by means of the free radicals scavenging activity, reducing power and inhibition of lipid peroxidation. The cytotoxicity of the different extracts was assessed in vitro against several human cancer cell lines (breast, lung, cervical and hepatocellular carcinomas) and, additionally, their hepatotoxicity was evaluated using a porcine liver primary cell culture. G. molle was shown to be rich in carbohydrates and proteins, providing tocopherols and essential fatty acids. Amongst the various extracts, the acetone extract was found to have the highest content of phenolic compounds (mainly ellagitannins, but also some flavone and flavonol glycosides) as well as the highest antioxidant and cytotoxic activities. To the best of our knowledge, this is the first report on the chemical composition and bioactive properties of G. molle.

A phenyl lipid alkaloid and flavone C-diglucosides from Spergularia marina

A phenyl lipid alkaloid and seven phenolic compounds were isolated from the aerial part of Spergularia marina, a halophyte that grows on salt marshes and tidal flat. These compounds were identified as 2,4-di-tert-butylphenol, N-hexacosanoylanthranilic acid, tryptophan, 4-hydroxybenzyol glucopyranoside, luteolin 6-C-β-D-glucopyranoside 8-C-β-D-(2-O-feruloyl)glucopyranoside, luteolin 6-C-β-D-(2-O-feruloyl)glucopyranoside 8-C-β-D-glucopyranoside, apigenin 6-C-β-D-glucopyranoside 8-C-β-D-(2-O-feruloyl)glucopyranoside, and apigenin 6-C-β-D-(2-O-feruloyl)glucopyranoside 8-C-β-D-glucopyranoside. The structures were determined by nuclear magnetic resonance and electrospray ionization-mass spectroscopy.

Determination of interglycosidic linkages in O-glycosyl flavones by high-performance liquid chromatography/photodiode-array detection coupled to electrospray ionization ion trap mass spectrometry. Its application to Tetragonula carbonaria honey from Australia

RATIONALE

Tetragonula carbonaria pot-honeys are highly valued as a food source and for their biological activities in Australia, and there is a growing interest to know its composition. Phenolic metabolites, which could be related to their beneficial properties, have not been studied in depth yet.

METHODS

Mass spectrometry (MS) coupled to liquid chromatography (LC) is an advanced technique for the study of complex flavonoids present in difficult food matrices that hampers their isolation and purification. This allows the tentative characterization of diglycosides/triglycosides establishing the position of the O-glycosylation on the sugar moiety by the study of the MS data in T. carbonaria pot-honeys from Australia.

RESULTS

Their spectra obtained by high-performance liquid chromatography/photodiode-array detection/electrospray ionization ion trap mass spectrometry (HPLC/DAD/ESI-MS(n) ) revealed for the first time 19 quercetin, kaempferol and isorhamnetin O-glycosides. These compounds were clustered in flavonoid triglycosides, diglycosides and monoglycosides. The first cluster contained one flavonoid trihexoside, two -3-O-(2-hexosyl, 6-rhamnosyl)hexosides and their isomers and two -3-O-(2,6-di-rhamnosyl)hexosides. In the second cluster, eleven flavonoid diglycosides such as three -3-O-(2-hexosyl)hexosides, four -3-O-(2-rhamnosyl)hexosides and one -3-O-(6-rhamnosyl)hexoside as well as two -3-O-(2-pentosyl)hexosides and one tentative -3-O-(3-pentosyl)hexoside were detected. In the monoglycoside group, only one flavonoid -3-O-hexoside was identified.

CONCLUSIONS

The occurrence of this large number of flavonoid glycosides could be due to the low glucosidase activity previously reported in stingless bee honey.

In vitro antibacterial phenolic extracts from "sugarbag" pot-honeys of Australian stingless bees (Tetragonula carbonaria)

Australian stingless bee honeys have been shown to exert antioxidant and in vitro antimicrobial properties; however their bioactive factors remained unidentified. This study investigated the antibacterial properties of phenolic extracts from Tetragonula carbonaria honeys. Honeys were harvested from beehives in three sites of South East Australia. Liquid-liquid extractions yielded the phenolic concentrates, for analyses by liquid and gas chromatography mass spectrometry. Antibacterial assays were conducted against Staphylococcus aureus and Klebsiella pneumoniae by in vitro agar diffusion and broth dilution assays. The phenolic extracts averaged to 5.87 mg/100 g of raw honeys, and constituents were 3-phenyllactic acid, lumichrome, diglycosylflavonoids, norisoprenoids. The honeys did not contain methylglyoxal, dihydroxyacetone or phenolics characteristic of Leptospermum nectars. Hydrogen peroxide content amounted up to 155.8 μM in honeys. Beside the bactericidal effects of hydrogen peroxide at 760 μM, other antibacterial factors were the phenolic extracts of "sugarbag" honeys that were active at minimum bactericidal concentrations of 1.2-1.8 mg/mL.

Characterization of flavonoid glycosides from fenugreek (Trigonella foenum-graecum) crude seeds by HPLC-DAD-ESI/MS analysis

Fenugreek (Trigonella foenum-graecum) is a medicinal plant which is widely used for its pharmacological properties. In this study the phenolic composition of fenugreek crude seeds originating from Morocco has been investigated. Extraction was performed from defatted seeds by a hydromethanolic solution using an Accelerated Solvent Extractor. HPLC technique coupled to negative ion electrospray ionization mass spectrometry and diode array detection was employed to identify the polyphenol in the obtained extract. The obtained results allowed the detection of 32 phenolic compounds among which various flavonoid glycosides and phenolic acids have been tentatively identified on the basis of their UV and MS spectra, and comparisons with standards when available, as well as with literature data. A systematic study of the obtained MS spectra and the observed fragmentation showed that most of the identified compounds were acylated and non-acylated flavonoids with apigenin, luteolin and kaempferol as aglycons. Hydroxycinnamic acids mostly dominated by caffeic acid derivatives were also detected. The quantitative analysis of the identified compounds showed that the phenolic composition of the studied crude fenugreek seeds was predominantly acylated and non-acylated flavone derivatives with apigenin as the main aglycon.

Approach to the study of flavone di-C-glycosides by high performance liquid chromatography-tandem ion trap mass spectrometry and its application to characterization of flavonoid composition in Viola yedoensis

The mass spectrometric (MS) analysis of flavone di-C-glycosides has been a difficult task due to pure standards being unavailable commercially and to that the reported relative intensities of some diagnostic ions varied with MS instruments. In this study, five flavone di-C-glycoside standards from Viola yedoensis have been systematically studied by high performance liquid chromatography-electrospray ionization-tandem ion trap mass spectrometry (HPLC-ESI-IT-MS(n)) in the negative ion mode to analyze their fragmentation patterns. A new MS(2) and MS(3) hierarchical fragmentation for the identification of the sugar nature (hexoses or pentoses) at C-6 and C-8 is presented based on previously established rules of fragmentation. Here, for the first time, we report that the MS(2) and MS(3) structure-diagnostic fragments about the glycosylation types and positions are highly dependent on the configuration of the sugars at C-6 and C-8. The base peak ((0,2) X1 (0,2) X(2)(-) ion) in MS(3) spectra of di-C-glycosides could be used as a diagnostic ion for flavone aglycones. These newly proposed fragmentation behaviors have been successfully applied to the characterization of flavone di-C-glycosides found in V. yedoensis. A total of 35 flavonoid glycosides, including 1 flavone mono-C-hexoside, 2 flavone 6,8-di-C-hexosides, 11 flavone 6,8-di-C-pentosides, 13 flavone 6,8-C-hexosyl-C-pentosides, 5 acetylated flavone C-glycosides and 3 flavonol O-glycosides, were identified or tentatively identified on the base of their UV profiles, MS and MS(n) (n = 5) data, or by comparing with reference substances. Among these, the acetylated flavone C-glycosides were reported from V. yedoensis for the first time.

Piper betle leaves: profiling phenolic compounds by HPLC/DAD-ESI/MS(n) and anti-cholinesterase activity

INTRODUCTION

Piper betle L. is a widely distributed plant in the tropical and subtropical regions, its leaves being largely consumed as a masticator and mouth freshener.

OBJECTIVE

The purposes of this work were to characterise the phenolic profile of this species and to improve knowledge of its anti-cholinesterase properties.

METHODS

The phenolic composition of P. betle leaf aqueous and ethanol extracts was characterised by HPLC coupled with a diode-array detector and combined with electrospray ionisation tandem MS, and in vitro cholinesterase inhibitory capacity of both extracts was assessed by spectrophotometric microassays. The effect on neuronal cells (SH-SY5Y) viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction and lactate dehydrogenase leakage.

RESULTS

Twelve phenolic compounds, comprising a phenylpropanoid, five cinnamoyl and six flavonoids derivatives were identified in P. betle leaves. Hydroxychavicol was the major compound in both extracts; however, the aqueous extract presented a greater diversity of compounds. Both extracts showed strong activity against both acetyl- and butyrylcholinesterase, which can be due, at least partially, to the phenolic composition. Furthermore, the aqueous extract proved to be cytotoxic to human neuroblastoma cells at concentrations higher than 500 µg/mL.

CONCLUSION

The results suggest that the consumption of P. betle leaves as an infusion can have a positive impact in the prevention and treatment of neurodegenerative diseases. Apigenin and luteolin derivatives are reported for the first time in this species.

A new iced tea base herbal beverage with Spergularia rubra extract: metabolic profile stability and in vitro enzyme inhibition

Beverages are an ideal format to offer nutrients, specific health-promoting functionality, and desirable sensory attributes to consumers. Taking into account previous research on Spergularia rubra (L.) J. Presl & C. Presl, the aim of this work was to describe the chemistry and biochemistry associated with the production of a new iced tea base herbal beverage containing a hydroethanolic extract of this species, including both naturally occurring and added components. Phenolic compounds of S. rubra hydroethanolic extract and of the iced tea base herbal beverage were determined by HPLC-DAD. Thirty compounds, comprising nonacylated C-glycosyl flavones, C-glycosyl flavones acylated with aromatic acids, and C-glycosyl flavones acylated with aliphatic acids, were identified, being essentially represented by apigenin derivatives. Organic acids of both samples were determined by HPLC-UV, malic acid being the major one. A strong inhibition of α-glucosidase, acetylcholinesterase, and butyrylcholinesterase was observed. Furthermore, the influence of the pH of the digestive tube on the chemical composition of both extract and iced tea base herbal beverage and, consequently, on their biological activity, was assessed. In a general way, pH variation significantly decreased (p < 0.05) the metabolites content and enzymes inhibitory capacity. Nevertheless, the beverage enriched with S. rubra extract represents a valuable addition to consumer's health and nutrition, once the loss of activity is lower than the one verified for the base iced tea. Thus, the results suggest that the ingestion of this beverage could be of potential interest for several chronic disorders, particularly Alzheimer's disease.

Characterization of phenolic compounds in flowers of wild medicinal plants from Northeastern Portugal

Crataegus monogyna, Cytisus multiflorus, Malva sylvestris and Sambucus nigra have been used as important medicinal plants in the Iberian Peninsula since a long time ago, and are claimed to have various health benefits. This study aimed to determine the phenolic profile and composition of wild medicinal flowers of those species. The analysis was performed by HPLC-DAD-ESI/MS. Flavonoids, and particularly flavonols and flavones, were the main groups in almost all the studied samples. C. multiflorus sample gave the highest levels of total flavonoids (54.5 mg/gdw), being a chrysin derivative the most abundant flavone found (22.3 mg/gdw). C. monogyna revealed the highest concentration in phenolic acids (5.5 mg/gdw) that were not found in C. multiflorus sample; 5-O-caffeoylquinic acid was the most abundant phenolic acid found in the first species, being a procyanidin trimer also found (1.4 mg/gdw). Kaempferol-3-O-rutinoside (0.84 mg/gdw) and quercetin-3-O-rutinoside (14.9 mg/gdw) were the main flavonols present in M. sylvestris and S. nigra, respectively. Due to the well established antioxidant activity of phenolic compounds, the studied wild medicinal flowers could be selected for processing extracts with health-promoting properties or to be incorporate into functional beverages or products with bioactive properties related to oxidative stress.

Structural characterization of phenolics and betacyanins in Gomphrena globosa by high-performance liquid chromatography-diode array detection/electrospray ionization multi-stage mass spectrometry

The metabolite profiling of Gomphrena globosa inflorescences was performed by high-performance liquid chromatography-diode array detection/electrospray ionization multi-stage mass spectrometry (HPLC-DAD/ESI-MS(n)). Based on the fragmentation patterns, 24 phenolic compounds were characterized. The identified phenolics include p-coumaric and ferulic acids, quercetin, kaempferol, isorhamnetin, and hydroxylated 6,7-methylenedioxyflavone derivatives, as well as their aglycones, none of them reported before in the species. This is also the first time that tetrahydroxy-methylenedioxyflavone derivatives and acetylglycosides are described in nature. Betacyanins were also found. This study significantly extends the knowledge of the G. globosa metabolome, by providing further insights into its phenolic composition.