LC-MSn identification and characterization of the phenolic compounds from the fruits of Flacourtia indica (Burm. F.) Merr. and Flacourtia inermis Roxb

Phenolic Compounds Characterization of Caryocar brasiliense Peel with Potential Antioxidant Activity

The pequi (Caryocar brasiliense) fruit peel, despite being frequently discarded, has a high content of bioactive compounds, and therefore has a high nutritional value. The present study aimed to explore the bioactivities in the pequi peel, particularly their potential health benefits at the level of antioxidant activity. The exploitation of this fruit could also present significant economic benefits and applications of pequi by-products would represent a reduction in waste, having a positive impact on the environment. Phenolic compounds present in the pequi exocarp and external mesocarp were identified by paper spray mass spectrometry (PS-MS) and quantified by HPLC. The total phenolic content (TPC) along with the amount of 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP), and the amount of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) were also determined in peel extracts. Epicatechin was the most abundant phenolic compound found, followed by the caffeic, salicylic, and gallic acids. In addition, fingerprinting revealed compounds related to several beneficial health effects. In short, the results obtained were encouraging for potential applications of pequi peel in the field of functional foods.

Metabolomic profiling and quantification of polyphenols from leaves of seven Acacia species by UHPLC-QTOF-ESI-MS

The genus Acacia (Fabaceae) comprises >1350 species and has been used in traditional medicine as infusions and decoctions to treat wounds, sores, headaches, diarrhea, and cough. The leaf methanolic extracts of seven Acacia species growing in Egypt namely: Acacia saligna, Acacia seyal, Acacia xanthophloea, Acacia tortilis subsp. raddiana., Acacia tortilis, Acacia laeta, Acacia albida were analyzed using UPLC-QTOF-ESI-MS. A total of 37 polyphenols were identified and discussed in detail. They included phenolic acids, flavonoids, and procyanidins, among which sixteen polyphenols were identified in Acacia for the first time. Folin-ciocalteau assay and ferric reducing antioxidant power, cupric reducing antioxidant capacity, 2,20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) cation radical and the scavenging capacity against 2,2-diphenyl-1- picrylhydrazyl radical were performed to investigate the total phenolic content and the antioxidant activity of the Acacia extracts, respectively. Furthermore, the absolute quantification of eighteen polyphenols common to most of the species was performed using UPLC-MS. It was evident that the differences in the chemical composition among the species accounted for the difference in antioxidant activity which was in line together with the total phenolic content.

Profiles of Free and Bound Phenolics and Their Antioxidant Capacity in Rice Bean (Vigna umbellata)

Rice bean (Vigna umbellata) is a medicinal and dietary legume rich in polyphenols. In this study, the free and bound phenolics in rice bean were extracted by water, 80% methanol, and acid, base, and composite enzymatic hydrolysis, respectively. The polyphenol profiles of the extracted fractions were analyzed. The outcome demonstrated that base hydrolysis was the most effective way to liberate bound phenolics from rice bean (14.18 mg GAE/g DW), which was 16.68 and 56.72 folds higher than those extracted by acid and enzymatic hydrolysis, respectively. The bound polyphenols released by base hydrolysis contributed to 71.15% of the total phenolic content. A total of 35 individual phenolics was identified, of which isoquercitrin, procyanidin B1, rutin, taxifolin, and catechin were the main monomeric phenolics in the free fraction, while gallic acid, protocatechuic acid, p-hydroxybenzoic acid, catechin, and phloroglucinol were the main monomeric phenolics in the bound fraction. In comparison to the free phenolics extracted by water and 80% methanol and the bound phenolics extracted using acid and composite enzymatic hydrolysis, the bound phenolics from base hydrolysis had a superior antioxidant capacity. The antioxidant activity of rice bean is primarily attributed to individual phenolics such as catechin, abundant both in free and bound fractions, and also p-hydroxybenzoic acid, gallic acid, and protocatechuic acid in bound fractions. The bound phenolics of rice bean were first reported and showed large differences with the composition of free phenolics. This work suggests that the bound fraction of rice bean must be taken into account in assessing its potential benefits to health.

Phytochemical-Based Evidence of the Health Benefits of Bidens Pilosa Extracts and Cytotoxicity

Purpose

Bidens pilosa L. is traditionally used as a flavouring agent in foods, in the treatment of diseases, in agriculture as a biopesticide and herbicide, and in the phytoremediation of soils contaminated with heavy metals. The vast range of uses of B. pilosa for a variety of purposes is questionable, hence motivating the objectives of this study, which are to assess the cytotoxicity, health benefits, and/or risks of B. pilosa using chemical-based evidence.

Methods

A real-time cell analysis (xCELLigence system), ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer, high-performance liquid chromatography with a diode array detector, and chemical-based spectrophotometric methods were adopted in the study.

Results

High concentrations of the ethanol extracts exhibited cytotoxic activity on HepG2 (cancerous), and Vero (non-cancerous) cell lines, whereas the water extracts promoted cell proliferation at selected concentrations. The chemical profiling enabled the separation as well as characterisation of 137 phytochemicals. These were mainly phenolic acids, flavonoids, fatty acids, coumarins, and furanocoumarins. There was no toxic compound identified.

Conclusion

The ethanol extracts are generally more potent and exhibit stronger antioxidant activity and cytotoxicity, probably due to the presence of more flavonoids and phenolic acids, validating the uses of B. pilosa and its relevance as a source of functional phytochemicals.

Salix subserrata Bark Extract-Loaded Chitosan Nanoparticles Attenuate Neurotoxicity Induced by Sodium Arsenate in Rats in Relation with HPLC-PDA-ESI-MS/MS Profile

Pollution is a worldwide environmental risk. Arsenic (As) is an environmental pollutant with a major health concern due to its toxic effects on multiple body organs, including the brain. Humans are exposed to As through eating contaminated food and water or via skin contact. Salix species (willow) are plants with medicinal efficacy. Salix subserrata Willd bark extract-loaded chitosan nanoparticles (SBE.CNPs) was formulated, characterized, and evaluated against As-induced neurotoxicity. The stem bark was selected for nanoparticle formulation based on HPLC-PDA-ESI-MS/MS profiling and in vitro antioxidant assessment using free radical scavenging activity. SBE.CNPs demonstrated an average un-hydrated diameter of 193.4 ± 24.5 nm and zeta potential of + 39.6 ± 0.4 mV with an encapsulation efficiency of 83.7 ± 4.3%. Compared to As-intoxicated rats, SBE.CNP-treated rats exhibited anxiolytic activity and memory-boosting as evidenced in open field test, light-dark activity box, and Y-maze. Also, it increased the antioxidant biomarkers, including superoxide dismutase and glutathione peroxidase associated with reducing the malondialdehyde levels and apoptotic activity. Besides this, SBE.CNPs maintained the brain architecture and downregulated both nuclear factor-kappa B and heme oxygenase-1 expression. These results suggest that SBE.CNP administration showed promising potent neuroprotective and antioxidative efficiencies against arsenic-induced oxidative threats.

Human Lung Cancer (A549) Cell Line Cytotoxicity and Anti-Leishmania major Activity of Carissa macrocarpa Leaves: A Study Supported by UPLC-ESI-MS/MS Metabolites Profiling and Molecular Docking

Lung cancer and cutaneous leishmaniasis are critical diseases with a relatively higher incidence in developing countries. In this research, the activity of Carissa macrocarpa leaf hydromethanolic extract and its solvent-fractions (n-hexane, EtOAc, n-butanol, and MeOH) against the lung adenocarcinoma cell line (A549) and Leishmania major was investigated. The MeOH fraction exhibited higher cytotoxic activity (IC₅₀ 1.57 ± 0.04 μg/mL) than the standard drug, etoposide (IC₅₀ 50.8 ± 3.16 μg/mL). The anti-L. major results revealed strong growth inhibitory effects of the EtOAc fraction against L. major promastigotes (IC₅₀ 27.52 ± 0.7 μg/mL) and axenic amastigotes (29.33 ± 4.86% growth inhibition at 100 μg/mL), while the butanol fraction exerted moderate activity against promastigotes (IC₅₀ 73.17 ± 1.62), as compared with miltefosine against promastigotes (IC₅₀ 6.39 ± 0.29 μg/mL) and sodium stibogluconate against axenic amastigotes (IC₅₀ 22.45 ± 2.22 μg/mL). A total of 102 compounds were tentatively identified using UPLC-ESI-MS/MS analysis of the total extract and its fractions. The MeOH fraction was found to contain several flavonoids and flavan-3-ol derivatives with known cytotoxic properties, whereas the EtOAc fractions contained triterpene, hydroxycinnamoyl, sterol, and flavanol derivatives with known antileishmanial activity. Molecular docking of various polyphenolics of the MeOH fraction with HDAC6 and PDK3 enzymes demonstrates high binding affinity of the epicatechin 3-O-β-D-glucopyranoside and catechin-7-O-β-D-glucopyranoside toward HDAC6, and procyanidin C2, procyanidin B5 toward PDK3. These results are promising and encourage the pursuit of preclinical research using C. macrocarpa's MeOH fraction as anti-lung cancer and the EtOAc fraction as an anti-L. major drug candidates.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Phenyl glycosides from the leaves of Flacourtia indica (Burm. f.) Merr (Salicaceae)

Thirteen phenolic glycosides, together with fourteen various known compounds, were isolated from the methanolic extract of leaves of Flacourtia indica. Twelve of these were composed of gentisyl or salicyl alcohols, glycosylated on the phenol and acylated on the primary alcohol with various more or less oxidized forms of pyrocatechuic acid. A number of positions on the glucose or on the acid were further acylated by benzoic or cinnamic acid. In addition to these, a glucoside of a phenyl propanoid was also isolated. The gross structures were elucidated by spectroscopic means including 1D and 2D NMR experiments and HR-ESI-MS analyses. Several of these structures, for example, xylosmin, were previously described but it proved extremely difficult to conclude on their exact identity with the absence of clear data on absolute configuration in the literature.

Flacourtia indica fruit extract modulated antioxidant gene expression, prevented oxidative stress and ameliorated kidney dysfunction in isoprenaline administered rats

This study evaluated the effect of Flacourtia indica fruit extract against isoprenaline (ISO) induced renal damage in rats. This investigation showed that ISO administration in rats increased the level oxidative stress biomarkers such as malondialdehyde (MDA), nitric oxide (NO), advanced protein oxidation product (APOP) in kidneys followed by a decrease in antioxidant enzymes functions. Flacourtia indica fruit extract, which is rich in strong antioxidants, also reduced the MDA, NO and APOP level in kidney of ISO administered rats. Inflammation and necrosis was also visible in kidney section of ISO administered rats which was significantly prevented by atenolol and Flacourtia indica fruit extract. Moreover, atenolol and Flacourtia indica fruit extract also modulated the genes expressions related to inflammation and oxidative stress in kidneys. The beneficial effects could be attributed to the presence of a number of phenolic antioxidants. This study suggests that Flacourtia indica fruit extract may prevent kidney dysfunction in ISO administered rats, probably by preventing oxidative stress and inflammation.

Chemical profiling, antimicrobial, anti-enzymatic, and cytotoxic properties of Phlomis fruticosa L

Structural diversity of biologically active compounds identified in plants after many years of storage is rarely reported in literature. Herein, we studied chemical profile and biological activities of Phlomis fruticosa L. after plant material storage for 20 years. Chemical analyzes were performed by UHPLC-LTQ-Orbitrap/MS, and revealed presence of 44 compounds: including 13 phenolic acids, 9 phenylethanoids, 20 flavonoids and 2 phenolic related compounds (a phenolic acid derivative and an aliphatic alcohol). The extract showed antimicrobial activity, being the most potent against Aspergillus fumigatus with minimum inhibitory concentration of 0.31 mg/mL. Also, the extract was able to inhibit biofilm formed by Candida species and to inhibit biofilm formation by Staphylococcus aureus. Obtained results revealed that the extract has potential to interfere with the cell membrane permeability of Candida albicans and to suppress production of virulence factor staphyloxanthin in S. aureus. Furthermore, the extract inhibited the activity of α-amylase which is one of the therapeutic targets for diabetes type II. Also, the antiproliferative effect of the extract was demonstrated on human cancer cell lines, while the extract did not exhibit any cytotoxic effect on primary human cells. Based on the obtained results, P. fruticosa could be an interesting source of biologically active compounds even after long term storage.

Characterization of Andean Blueberry in Bioactive Compounds, Evaluation of Biological Properties, and In Vitro Bioaccessibility

The aim of this study was to evaluate Andean blueberries (Vaccinium floribundum Kunth) from Ecuador as a potential functional ingredient for the food and pharmaceutical industries. The analysis of bioactive compounds by HPLC–DAD–MSⁿ determined a high content of (poly)phenols, mainly anthocyanins, and the presence of the carotenoid lutein. Regarding its biological properties, Andean blueberry did not show toxicity by the zebrafish embryogenesis test, showing also a lack of the antinutrients lectins. Moreover, the results of in vitro and in vivo antioxidant capacity evaluation suggested its possibility to be used as natural antioxidant. This fruit also exhibited antimicrobial activity toward Staphylococcus aureus and Escherichia coli in low doses. Finally, in vitro gastrointestinal (GI) digestion showed a partial bioaccessibility of (poly) phenols (~50% at the final step), showing high antioxidant capacity in the different GI phases. These results revealed Andean blueberry as an interesting candidate for being used as a functional ingredient and the development of further in vivo and clinical assays.

Chemical composition and antimycoplasma activity of a brown propolis from southern Brazil

Extracts of a sample of brown propolis produced in the district of Itapará (Southern Brazil) were obtained with solvents with increasing polarity. The extracts were analyzed by RPHPLC-DAD-ESI-MS/MS and evaluated toward activity against Mycoplasma bovis, M. gallisepticum, M. genitalium, M. hominis, M. hyorinis, M. penetrans and M. pneumonieae. Typical components of "alecrim-do-campo" propolis (e.g. prenylated phenylpropanoids and caffeoyl-quinic acids) were characterized in the analyzed extraccts, in addition to several flavonols. Less polar extracts showed higher anti-mycoplasma activity (MIC value commonly 3.9 μg/mL) than alcoholic and aqueous extracts (MIC value often 7.8-250 μg/mL). The results indicate that Itapará propolis is a promising source for the development of therapeutic drugs.

In vitro pro-inflammatory enzyme inhibition and anti-oxidant potential of selected Sri Lankan medicinal plants

Background

The extracts of the ten selected Sri Lankan medicinal plants have been traditionally used in the treatment of inflammatory mediated diseases. The extracts were investigated for anti-inflammatory and anti-oxidant potential in vitro to identify bio-active extracts for further chemical characterization.

Methods

In vitro anti-inflammatory activities of total ethanol extracts were investigated measuring the inhibitory activities of four pro-inflammatory enzymes, arachidonate-5- lipoxygenase (A5-LOX), hyaluronidase (HYL), xanthine oxidase (XO) and inducible nitric oxide (iNO) synthase. Cytotoxicity of extracts were determined by MTT assay. Oxidative burst inhibition (OBI) on human whole blood (WB) and isolated polymorphoneutrophils (PMNs) was carried out for a selected bio-active extract. Anti- oxidant activities of the extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, ferric reducing antioxidant power (FRAP), ferrous ion chelation (FIC) and oxygen radical absorbance capacity (ORAC) assays. Total polyphenol and total Flavonoid contents of the extracts were also determined. The most active plant extract was analysed using Gas chromatography-Mass spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC).

Results

The ethanol bark extract of Flacourtia indica showed the highest A5-LOX (IC₅₀: 22.75 ± 1.94 g/mL), XO (70.46 ± 0.18%; 250 μg/mL) and iNOs inhibitory activities on LPS- activated raw 264.7 macrophage cells (38.07 ± 0.93%; 500 μg/mL) with promising OBI both on WB (IC₅₀: 47.64 2.32 μg/mL) and PMNs (IC₅₀: 5.02 0.38 μg/mL). The highest HYL inhibitory activity was showed by the leaf extracts of Barathranthus nodiflorus (42.31 ± 2.00%; 500 μg/mL) and Diospyros ebenum (41.60 ± 1.18%; 500 μg/mL). The bark and leaf extracts of Callophyllum innophyllum (IC₅₀: 6.99 ± 0.02 μg/mL) and Symplocus cochinchinesis (IC₅₀: 9.85 ± 0.28 μg/mL) showed promising DPPH free radical scavenging activities. The GC-MS analysis of ethanol bark extract of F. indica showed the presence of two major bio-active compounds linoleic acid ethyl ester and hexadecanoic acid, ethyl ester (> 2% peak area). The HPLC analysis showed the presence polyphenolic compounds.

Conclusion

The ethanol bark extract of F. indica can be identified as a potential candidate for the development of anti-inflammatory agents, which deserves further investigations. The bio-active plant extracts may be effectively used in the applications of cosmetic and health care industry.

Non-targeted glycosidic profiling of international wines using neutral loss-high resolution mass spectrometry

Many metabolites naturally occur as glycosides, since sugar moieties can be crucial for their biological activity and increase their water solubility. In the plant kingdom they may occur as glycosides or sugar esters, depending on precursor chemical structure, and in wine they have traditionally attracted attention due to their organoleptic properties, such as astringency and bitterness, and because they affect the colour and aroma of wines. A new approach directed at detailed description of glycosides in a large selection of monovarietal wines (8 samples each of Pinot Blanc, Muller Thurgau, Riesling, Traminer, Merlot, Pinot Noir and Cabernet Sauvignon) was developed by combining high performance liquid chromatography with high resolution tandem mass spectrometry. Analytical separation was performed on an Accucore™ Polar Premium LC column, while mass analysis was performed in negative ion mode with an non-targeted screening approach, using a Full MS/AIF/NL dd-MS² experiment at a resolving power of 140,000 FWHM. Over 280 glycoside-like compounds were detected, of which 133 (including low-molecular weight phenols, flavonoids and monoterpenols) were tentatively identified in the form of pentose (6), deoxyhexose (17), hexose (73), hexose-pentose (16), hexose-deoxyhexose (7), dihexose (5) and hexose ester (9) derivatives. It was not possible to univocally define the corresponding chemical structure for the remaining 149 glycosides. Non-parametric statistical analysis showed it was possible to well characterise the glycosylated profile of all red and Traminer wines, while the identified glycosides were almost entirely lacking in Pinot Blanc, Riesling and Muller Thurgau wines. Also Tukey's Honestly Significant Difference test (p < 0.05) and Principal Component Analysis confirmed that it was possible to almost entirely distinguish the selected red wines from each other according to their glycosylated profile.

Profiling and Quantification of Regioisomeric Caffeoyl Glucoses in Berry Fruits

On the basis of a recently developed tandem mass spectrometry-based hierarchical scheme for the identification of regioisomeric caffeoyl glucoses, selected berry fruits were profiled for their caffeoyl glucose ester content. Fresh edible berries profiled, including strawberries, raspberries, blueberries, blackberries, red currant, black currant, lingonberries, gooseberries, and juices of elderberries, goji berries, chokeberries, cranberries, açai berries, sea buckthorn berries, Montmorency sour cherries, and pomegranates, were investigated. 1-Caffeoyl glucose was found to be the predominant isomer in the majority of samples, with further profiling revealing the presence of additional hydroxycinnamoyl glucose esters and O-glycosides with p-coumaroyl, feruloyl, and sinapoyl substituents. A quantitative liquid chromatography-mass spectrometry-based method was developed and validated, and all caffeoyl glucose isomers were quantified for the first time in edible berries.

Broad bean (Vicia faba L.) pods: a rich source of bioactive ingredients with antimicrobial, antioxidant, enzyme inhibitory, anti-diabetic and health-promoting properties

Broad bean pods have been proven to be a functional food with promising in vitro and in vivo biological activities.

Profiling and quantification of regioisomeric caffeoyl glucoses in Solanaceae vegetables

Based on the recently developed tandem MS based hierarchical scheme for the identification of regioisomeric caffeoyl glucoses, selected vegetables were profiled with respect to their caffeoyl glucose content. The dietary plants profiled were tomato, pepper, chilli and aubergine, all members of the Solanaceae family. 6-O-caffeoyl glucose was found to be the predominant isomer. In processed food such as tomato puree and ketchup a larger number of caffeoyl-glucose isomers formed through acyl migration reactions were observed. A LC-MS based quantitative method was developed, validated and caffeoyl glucose regioisomers quantified for the first time in dietary plants with quantitative data obtained from representative 30 food samples.

New pentose dimers with bicyclic moieties from pretreated biomass

Dipentoses with bicyclic moieties are proposed as new putative cellulase inhibitory reaction products forming during hydrothermal wheat straw biomass pretreatment.

Identification and characterization of phenolic compounds in hydromethanolic extracts of sorghum wholegrains by LC-ESI-MS(n)

Hydromethanolic extracts of brown, red, and white sorghum whole grains were analysed by LC-MS(n) in negative ESI mode within the range m/z 150-550amu. Besides the flavonoids already reported in sorghum, a number of flavonoids were also identified in the sorghum grain for the first time, including flavanones, flavonols and flavanonols, and flavan-3-ol derivatives. Various phenylpropane glycerides were also found in the sorghum grain, the majority of them are reported here for the first time, and a few of them were detected with abundant peaks in the extracts, indicating they are another important class of phenolic compounds in sorghum. In addition, phenolamides were also found in sorghum grain, which have not been reported before, and dicaffeoyl spermidine was detected in high abundance in the extracts of all three type sorghum grains. These results confirmed that sorghum is a rich source of various phenolic compounds.

Chlorogenic Acids Biosynthesis in Centella asiatica Cells Is not Stimulated by Salicylic Acid Manipulation

Exogenous application of synthetic and natural elicitors of plant defence has been shown to result in mass production of secondary metabolites with nutraceuticals properties in cultured cells. In particular, salicylic acid (SA) treatment has been reported to induce the production of phenylpropanoids, including cinnamic acid derivatives bound to quinic acid (chlorogenic acids). Centella asiatica is an important medicinal plant with several therapeutic properties owing to its wide spectrum of secondary metabolites. We investigated the effect of SA on C. asiatica cells by monitoring perturbation of chlorogenic acids in particular. Different concentrations of SA were used to treat C. asiatica cells, and extracts from both treated and untreated cells were analysed using an optimised UHPLC-QTOF-MS/MS method. Semi-targeted multivariate data analyses with the aid of principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA) revealed a concentration-dependent metabolic response. Surprisingly, a range of chlorogenic acid derivatives were found to be downregulated as a consequence of SA treatment. Moreover, irbic acid (3,5-O-dicaffeoyl-4-O-malonilquinic acid) was found to be a dominant CGA in C. asiatica cells, although the SA treatment also had a negative effect on its concentration. Overall SA treatment was found to be an ineffective elicitor of CGA production in cultured C. asiatica cells.

Neuraminidase inhibition of Dietary chlorogenic acids and derivatives – potential antivirals from dietary sources

Plants rich in chlorogenic acids (CGAs), caffeic acids and their derivatives have been found to exert antiviral effects against influenza virus neuroaminidase.

Comparison between Folin-Ciocalteu and Prussian Blue Assays to Estimate The Total Phenolic Content of Juices and Teas Using 96-Well Microplates

Folin-Ciocalteu colorimetric assay (FC) is the most widely used assay to estimate the total phenolic content in foods, beverages, herbs and other plant extracts, but many chemical compounds may act as interfering agents, producing inaccurate estimations of the real concentration of phenolic compounds in the matrix. Based on this limitation, the objective of this study was to compare, quantitatively, the Folin-Ciocalteu and Prussian Blue (PB) assays in estimating the total phenolic content in purple grape juices (n = 20; Vitis labrusca L.) and teas (n = 25) from different botanical origins using 96-well microplates. PB assay presented a low limit of detection (PB = 0.27 mg/L; FC = 0.25 mg/L) and quantification (PB = 0.92 mg/L; FC = 0.82 mg/L), showing its suitability in screening the total phenolic content in grape juices and teas. FC and PB assays presented a high association (P < 0.0001) for teas (r = 0.887) and grape juices (r = 0.923). The advantages of PB over FC assay are its simplicity, low time consumption (15 min reaction as compared to 60 min reaction for the FC assay), lower usage of reagents (solutions are prepared in a mM base), and higher selectivity. Additionally, PB assay was proven to be reproducible and repeatable and, therefore, may be used as an alternative to FC assay.

PRACTICAL APPLICATION

Prussian Blue assay (PB) has been used as an alternative to Folin-Ciocalteu assay (FC) to estimate the total content of phenolic compounds in herbs and some natural products. In our study we showed that the advantages of PB assay over FC are its simplicity, low time consumption (15 min reaction as compared to 60 min reaction for the FC assay), lower usage of reagents (solutions are prepared in a mM base) and higher selectivity as compared to FC assay. Additionally, PB assay was proven to be reproducible and repeatable and, therefore, may be used as an alternative to FC assay.

New insights into the qualitative phenolic profile of Ficus carica L. fruits and leaves from Tunisia using ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry and their antioxidant activity

RP-UHPLC-DAD-QTOF-MS gives new insights into the fig phenolic constituents that correlate with their antioxidant potency.

Identification and characterization of chlorogenic acids, chlorogenic acid glycosides and flavonoids from Lonicera henryi L. (Caprifoliaceae) leaves by LC-MSn

The chlorogenic acids, chlorogenic acid glycosides and flavonoids of the leaves of Lonicera henryi L. (Caprifoliaceae) were investigated qualitatively by liquid chromatography tandem mass spectrometry. Thirty-one chlorogenic acids and their glycosides were detected and characterized to their regioisomeric level on the basis of their unique fragmentation pattern in the negative ion mode tandem MS spectra. All of them were extracted for the first time from this source and thirteen of them were not reported previously in nature. For the positive identification of chlorogenic acid glycosides by LC-MS(n), multiple reaction monitoring and targeted MS(n) experiments were performed. We have developed an LC-MS(n) method for the systematic identification of chlorogenic acid glycosides and were also able to discriminate between chlorogenic acids and their isobaric glycosides. It was also possible to discriminate between 5-O-(3'-O-caffeoyl glucosyl)quinic acid and 5-O-(4'-O-caffeoyl glucosyl)quinic acid by LC-MS(n). This method can be applied for the rapid and positive identification of chlorogenic acids and their glycosides in plant materials, food and beverages.

Hierarchical key for the LC-MSn identification of all ten regio- and stereoisomers of caffeoylglucose

A chromatographic method was developed to separate all 10 regio- and stereoisomers of caffeoylglucose. Following chromatographic separation on reversed phase, the fragmentation behavior of all 10 regio- and stereoisomers of caffeoylglucose has been investigated using LC-MS(n). It is possible to discriminate between each of the isomers based on their characteristic fragment spectra and order of elution, including those for which commercial standards are not available. On the basis of the synthesis of authentic standards for 6-caffeoylglucose and 3-caffeoylglucose and nonselective further synthesis of suitable mixtures of isomers, it was possible to fully assign regiochemistry of all 10 isomeric compounds and stereochemistry of eight isomeric compounds. Their fragmentation pattern was rationalized based on assuming different hydrogen-bonding arrays of gas-phase ions opening distinct fragmentation pathways. An analysis of yerba maté extract showed all 10 regio- and stereoisomers of caffeoylglucose to be present in this dietary material, which could all be assigned to regioisomeric level and eight to stereoisomeric level.