Formation of Cysteine Adducts with Chlorogenic Acid in Coffee Beans

The post-harvest processing of coffee beans leads to a wide range of reactions involving proteins. The formation of crosslinks between proteins and phenolic compounds present in high concentrations of coffee beans represents one of the most challenging and still not fully characterized reactions. The aim of this work was to assess the presence of products from such reactions in coffee samples, focusing on the adducts between cysteine and chlorogenic acids (CQAs). For this purpose, 19 green and 15 roasted coffee samples of the Coffea arabica, Coffea canephora, and Coffea liberica varieties were selected for this study and basically characterized. Then, targeted liquid chromatography mass spectrometry (LC-MS/MS) methods were developed to assess the formation of adducts between CQA and cysteine, glutathione, and N-acetylcysteine as the amino acid and peptide models, and quantified such adducts in coffee samples. The results of the characterization showed a heterogeneous distribution of the protein content (8.7-14.6%), caffeine (0.57-2.62 g/100 g), and antioxidant capacity (2-4.5 g ascorbic acid/100 g) in Arabica, Canephora, and Liberica samples. Glutamic acid, arginine, and proline were found to be the major amino acids, while 5-CQA (38-76%), 3-CQA (4-13%), and 4-CQA (4-13%) were the most abundant CQA derivatives of all coffee varieties. The model experiments for adduct formation demonstrated that cysteine binds to CQA via thiol groups and 5-CQA initially isomerizes to 3- and 4-CQA, depending on the conditions, allowing cysteine to bind to two different sites on 3-, 4- or 5-CQA molecules, thus, forming six different Cys-CQA adducts with m/z 476. The reaction was more favored at pH 9, and the adducts proved to be stable up to 90 °C for 10 min and up to 28 days at room temperature. The relative quantification of adducts showed peak area values ranging from 1100 to 3000 in green coffee bean samples, while no adducts were detected in roasted coffee beans. Overall, this work was the first attempt to demonstrate the presence of Cys-CQA adducts in coffee beans and paves the way for further investigations of such adduct formation at the protein level.

Chemometrics-Driven Variability Evaluation of Phenolic Composition, Antioxidant Capacity, and α-Glucosidase Inhibition of Sorbus aucuparia L. Fruits from Poland: Identification of Variability Markers for Plant Material Valorization

Sorbus aucuparia L. (rowan tree) is a widely distributed European plant, valued for its nutritional and medicinal qualities. The medicinal application of rowanberries, relying particularly on their antioxidant and antidiabetic effects, is closely connected with the presence of numerous phenolic compounds. However, the broad geographical occurrence of rowan trees may contribute to fluctuations in fruit composition, influencing their biological properties. This study aimed to identify the constituents most involved in this variability to facilitate effective quality control. The investigation encompassed 20 samples collected from diverse locations across Poland, evaluated in terms of the variation in composition and bioactivity. The UHPLC-PDA-ESI-MSn study identified 45 different constituents, including flavonoids, phenolic acid and flavon-3-ols. The detected compounds were quantitatively assessed by HPLC-PDA, alongside spectrophotometric evaluation of total phenolic content and the content of high-molecular-weight proanthocyanidins (TPA). Additionally, •OH scavenging capacity and α-glucosidase inhibition were included as bioactivity parameters. Chemometric analyses, including hierarchical cluster analysis and principal component analysis, revealed geographically dependent variability, with low to moderate variation observed for most factors (variation coefficients 20.44-44.97%), except for flavonoids (variation coefficients 45-76%). They also enabled the selection of seven constituents and TPA as the key markers of variability and biological activity of rowanberries. These markers could be employed for quality control of the fruits, offering a more efficient and cost-effective approach compared to full phytochemical analysis.

Unbiased and biased chemometric analysis of LC-MS data from human urine following coffee intake

We carried out a human volunteer study with 14 participants, eight of whom were asked to consume one cup of coffee at four different time points. Urine samples were collected at eight time points and analyzed by HPLC-MS analysis. The LC-MS data were subjected to unsupervised multivariate statistical analysis (principal component analysis) followed by supervised multivariate analysis (linear discriminant analysis). In an unbiased approach, in the absence of data preselection and filtering, the most important features explaining differences between coffee consumers and the control group observed showed variations in endogenous human hormonal steroid metabolites as well as xanthine derivatives. Only after a biased data treatment data revealed differences between the sample groups based on literature reported chlorogenic acid metabolites resulting directly from coffee intake. Such analysis could confirm the presence of 21 previously reported chlorogenic acid plasma metabolites as urinary metabolites. The application of tandem MS molecular networking revealed the presence of five bioavailable chlorogenic acid derivatives in urine previously not reported, including both quinic acid lactone and dimethoxy caffeoyl esters. Selected cinnamic acids were quantified in urine.

A Nanotechnological Approach to Exploit and Enhance the Bioactivity of an Extract from Onopordum illyricum L. Leaves

Plant-derived products have been used for preventive and curative purposes from the ancient era to the present day. Several studies have demonstrated the efficacy of either multicomponent-based extracts, enriched fractions, or isolated bioactives. However, they often display low solubility and bioavailability, chemical instability, poor absorption, and even toxicity, which restrict application in therapy. The use of drug delivery systems, especially nanocarriers, can overcome these physicochemical and pharmacokinetic limitations. In this study, an extract from Onopordum illyricum leaves was produced by maceration in 80% ethanol, characterized by liquid chromatography coupled to mass spectrometry, and formulated in phospholipid vesicles with the aim of exploiting and possibly enhancing its bioactivity for skin delivery. The results showed that phenolic compounds were abundantly present in the extract, especially hydroxycinnamic acid and flavonol derivatives. The extract-loaded vesicles showed small size (<100 nm), high entrapment efficiency (even >90% for most phenolic compounds), and good long-term stability. Moreover, the extract-loaded vesicles exhibited remarkable antioxidant activity, as demonstrated by colorimetric assays and by enhanced reduction of intracellular reactive oxygen species (ROS) levels in cultured skin cells. Hence, our findings support the key role of nanotechnological approaches to promote the potential of plant extracts and strengthen their application in therapy.

The burdock database: a multi-omic database for Arctium lappa, a food and medicinal plant

BACKGROUND

Burdock is a biennial herb of Asteraceae found in Northern Europe, Eurasia, Siberia, and China. Its mature dry fruits, called Niu Bang Zi, are recorded in various traditional Chinese medicine books. With the development of sequencing technology, the mitochondrial, chloroplast, and nuclear genomes, transcriptome, and sequence-related amplified polymorphism (SRAP) fingerprints of burdock have all been reported. To make better use of this data for further research and analysis, a burdock database was constructed.

RESULTS

This burdock multi-omics database contains two burdock genome datasets, two transcriptome datasets, eight burdock chloroplast genomes, one burdock mitochondrial genome, one A. tomentosum chloroplast genome, one A. tomentosum mitochondrial genome, 26 phenotypes of burdock varieties, burdock rhizosphere-associated microorganisms, and chemical constituents of burdock fruit, pericarp, and kernel at different growth stages (using UPLC-Q-TOF-MS). The wild and cultivation distribution of burdock in China was summarized, and the main active components and pharmacological effects of burdock currently reported were concluded. The database contains ten central functional modules: Home, Genome, Transcriptome, Jbrowse, Search, Tools, SRAP fingerprints, Associated microorganisms, Chemical, and Publications. Among these, the "Tools" module can be used to perform sequence homology alignment (Blast), multiple sequence alignment analysis (Muscle), homologous protein prediction (Genewise), primer design (Primer), large-scale genome analysis (Lastz), and GO and KEGG enrichment analyses (GO Enrichment and KEGG Enrichment).

CONCLUSIONS

The database URL is http://210.22.121.250:41352/ . This burdock database integrates molecular and chemical data to provide a comprehensive information and analysis platform for interested researchers and can be of immense help to the cultivation, breeding, and molecular pharmacognosy research of burdock.

Preliminary Characterization of Phytochemicals and Polysaccharides in Diverse Coffee Cascara Samples: Identification, Quantification and Discovery of Novel Compounds

Coffee cascara is the first and most significant by-product of the coffee processing industry, whose valorization has become an urgent priority to reduce harmful environmental impacts. This work aimed to provide an improved understanding of phytochemicals and polysaccharides in coffee cascara in order to offer information for the better evaluation of potential applications. Phytochemicals in 20 different coffee cascara samples were ultrasonically extracted and analyzed by HPLC-UV and HPLC-MS/MS. Four novel compounds were isolated for the first time from coffee cascara, including two still unknown tautomers (337 Da), and two dihydroflavonol glycosides (dihydromyricetin glycoside and dihydromyricetin rhamnosylglycoside). Their presence can contribute to the design of new value-added applications of coffee cascara. Chemical characterization of two polysaccharides from two of the coffee cascara pulp samples showed that they were mainly composed of homogalacturonan, with rhamnose and arabinose as minor neutral sugars. In addition, principal component analysis results indicated that coffee cultivar and/or country significantly impacted the phytochemical composition of coffee cascara, although differences may be reduced by the external environment and processing method. It is suggested that processing method should be carefully designed when generating coffee cascara from the same cultivar and country/farm.

Rapid identification of chemical constituents in Yinqiao Powder using ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight tandem mass spectrometry with data filtering strategy

Yinqiao Powder is a classic and effective prescription for the treatment of many kinds of pneumonia in China. To date, the chemical constituents had not been uncovered. Comprehensive identification of chemical constituents provided a structure basis to discover the potential anti-pneumonia ingredients in Yinqiao Powder. In this paper, ultra-high performance liquid chromatography coupled to quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) analysis with diagnostic product ions and neutral loss filtering strategy were established and applied for the comprehensive chemical profiling of Yinqiao Powder, which simplified structure elucidation of chemical constituents in Yinqiao Powder. A total of 124 compounds, including 8 C6-C2 glucoside conjugates, 28 iridoid glycosides, 14 lignans, 21 phenylethanol glycosides, 20 triterpenoid saponins, 9 chlorogenic acids and 24 flavonoids were rapidly identified in Yinqiao Powder, and 32 of them were characterized by comparing their MS/MS data and retention time with reference standards. The results indicated that UHPLC-QTOF-MS/MS method coupled with data filtering strategy was feasible and rational to identify the complex chemical constituents of Yinqiao Powder, which would be conducive to discover the active ingredients of Yinqiao Powder for the treatment of pneumonia and establish its quality standard.

Mechanistic insights on burdock (Arctium lappa L.) extract effects on diabetes mellitus

Diabetes mellitus (DM) type 2 is amongst the most common chronic diseases, being responsible for various problems in humans and contributing to increased mortality rates worldwide. Fructooligosaccharide, which can be produced from the roots of burdock (Arctium lappa L.), has been shown to have a wide range of pharmacological proprieties, including antiviral, anti-inflammatory, hypolipidemic, and antidiabetic effects. Moreover, burdock also contains chlorogenic acid, which has been used in traditional medicine as an antioxidant. Considering its natural origin and minimal toxicity, burdock fructooligosaccharides (BFO) has gained considerable attention from researchers owing its wide, efficient, and beneficial action against DM. Although the effectiveness of fructooligosaccharide and chlorogenic acid has been extensively discussed, limited information is available on the application of burdock for DM treatment. In this review, we discuss the beneficial contributions, and the recent in vitro and in vivo analytical findings on A. lappa extract as DM therapy.

Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds

The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4–8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma.

Characterization of chemical components and the potential anti-influenza mechanism of Fructus Arctii by a strategy integrating pharmacological evaluations, chemical profiling, serum pharmacochemistry, and network pharmacology

Chemical components in traditional Chinese medicine (TCM) were the functional basis for its therapy achievement, and the absorbed components under disease conditions were mainly contributing to the therapeutic effects. As...

The ethnopharmacology, phytochemistry, pharmacology and toxicology of the genus Erycibe (Convolvulaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Erycibe belongs to the Convolvulaceae family that contains approximately 70 species mainly distributed from tropical and subtropical Asia to north of Australia. Several Erycibe species are traditionally used in folk medicine for the treatment of various ailments, including rheumatic arthralgia, primary glaucoma, hepatopathies, and infectious and malignant diseases.

AIM OF THE REVIEW

This review aims to summarize comprehensive and updated information on traditional medicinal uses, phytochemistry, pharmacology, and toxicology of Erycibe species to provide a reference for the further research and application of the Erycibe genus.

MATERIALS AND METHODS

The scientific and extensive literatures between 1975 and 2020 were systematically gathered from scientific databases such as SciFinder Scholar, Science Direct, Web of Science, PubMed, Google Scholar, Scopus, Springer Link and China National Knowledge Infrastructure (CNKI), as well as Chinese herbal classic books, PhD and MSc theses, and several official websites.

RESULTS

Erycibe species have been used for the treatment of various rheumatoid diseases, glaucoma, a variety of hepatic diseases, infectious diseases and various malignancies in the traditional and local medicine. Since the 1970s, 153 compounds, including coumarins, quinic acid derivatives, flavonoids, alkaloids, lignans, and others have been isolated from five species of the Erycibe genus. Pharmacological studies have shown that these extracts and compounds from the Erycibe genus have extensive activities consistent with the traditional and local applications, such as anti-glaucoma, anti-arthritic, hepatoprotective and anti-cancer activities, as well as anti-inflammatory, anti-respiratory syncytial virus (RSV), and neuroprotective properties.

CONCLUSIONS

Although there are extensive data on the genus Erycibe, certain specific gaps still exist. For herbal preparations containing Erycibe species, clinical toxicological investigation is required for the safety of these herbal preparation therapies, as well as further investigations on pharmacokinetics and bioavailability for guideline for clinical application. Furthermore, more detailed pharmacological, toxicological and clinical researches are needed to assess the alternatives to Erycibe species. Systematic and comprehensive pre-clinical studies are similarly required to estimate the possibility of extracts and compounds from the genus Erycibe with bioactivity developing into new drugs.

Comparison of Nutritional and Nutraceutical Properties of Burdock Roots Cultivated in Fengxian and Peixian of China

This study aimed to analyze and compare the nutritional quality of powders of burdock root from Fengxian (FX) and Peixian (PX) in China. The nutrient composition including carbohydrates, protein, amino acids, vitamin C, carotenoids, as well as total phenols, total flavonoids and phenolic compounds were investigated in addition to in vitro antioxidant capacity. The results showed that the basic nutrients of burdock root powder (BRP) in both locations did not have significant differences (p > 0.05), although the in vitro antioxidant capacity of BRP of Fengxian (F-BRP) was greater than that of PX (p < 0.05). The burdock root peel powder (BRPP) possessed more phenolics and stronger in vitro antioxidant capacity than the burdock root powder (BRP) and peeled burdock root powder (PBRP) (p < 0.05). Moreover, better quality burdock root was obtained from FX. F-BRP was consequently analyzed by ultra-performance liquid chromatography tandem mass spectrometry for its phenolic composition. Seventeen phenolics, mainly caffeoylquinic acids, were detected. In addition, a total of 181 volatile compounds belonging to eight types were detected including alcohols, aldehydes, ketones, alkenes, esters, acids, linear or aromatic hydrocarbons, and others. The diverse compounds found in this study can provide a theoretical basis for the development and utilization of burdock in the food industry.

Novel insight into biological activity and phytochemical composition of Sorbus aucuparia L. fruits: Fractionated extracts as inhibitors of protein glycation and oxidative/nitrative damage of human plasma components

Sorbus aucuparia L. is a source of edible fruits appreciated for their nutritional and medicinal properties. In this work some bioactivity mechanisms were evaluated, which might be connected with the traditional application of rowanberries in cardiovascular complications of diabetes. With the use of a panel of chemical and biological in vitro models the rowanberry extracts were proved to significantly inhibit the formation of advanced glycation end products, neutralise multiple oxidants generated in vivo, increase the non-enzymatic antioxidant capacity of human plasma and protect plasma components (proteins and lipids) against oxidative/nitrative damage at in vivo-relevant levels (1-5 µg/mL). Moreover, the extracts were found safe in cytotoxicity tests on the peripheral blood mononuclear cells. The comprehensive phytochemical profiling of the extracts (RP/HILIC-UHPLC-PDA-ESI-MS³, HPLC-PDA, and UV-spectrophotometric methods) led to the identification of 51 phenolics, including caffeic and ferulic acids pseudodepsides (34 compounds, prevailing isomers of chlorogenic acid and cynarin, total content up to 269.4 mg/g), flavonols (mostly quercetin glycosides, up to 5.8 mg/g), flavan-3-ol derivatives (proanthocyanidin oligomers and polymers, up to 17.0 mg/g), and simple phenolic acids. The experiments on model constituents of the extracts and correlation studies were used to evaluate contribution of polyphenols to the observed effects. Taking into account the possible additive and synergistic effects, the co-occurrence of various compounds was indicated as partly responsible for biological activity of the fruits. Considering both the composition and activity parameters, the methanol-water (1:1, v/v) extract and its concentrated phenolic fractions appeared to be the most advantageous for biological application.

Uncovering the pharmacological mechanisms of Xijiao Dihuang decoction combined with Yinqiao powder in treating influenza viral pneumonia by an integrative pharmacology strategy

Xijiao Dihuang decoction combined with Yinqiao powder (XDD-YQP) is a classical combination formula; however, its therapeutic effects in treating influenza viral pneumonia and the pharmacological mechanisms remain unclear. The therapeutic effect of XDD-YQP in influenza viral pneumonia was evaluated in mice. Subsequently, an everted gut sac model coupled with UPLC/Q-TOF MS were used to screen and identify the active compounds of XDD-YQP. Furthermore, network pharmacological analysis was adopted to probe the mechanisms of the active compounds. Lastly, we verified the targets predicted from network pharmacological analysis by differential bioinformatics analysis. Animal experiments showed that XDD-YQP has a therapeutic effect on influenza viral pneumonia. Moreover, 113 active compounds were identified from intestinal absorbed solutions of XDD-YQP. Using network pharmacological analysis, 90 major targets were selected as critical in the treatment of influenza viral pneumonia through 12 relevant pathways. Importantly, the MAPK signaling pathway was found to be closely associated with the other 11 pathways. Moreover, seven key targets, EGFR, FOS, MAPK1, MAP2K1, HRAS, NRAS, and RELA, which are common targets in the MAPK signaling pathway, were investigated. These seven key targets were identified as differentially expressed genes (DEGs) between influenza virus-infected and uninfected individuals. Hence, the seven key targets in the MAPK signaling pathway may play a vital role in the treatment of influenza viral pneumonia with XDD-YQP. This research may offer an integrative pharmacology strategy to clarify the pharmacological mechanisms of traditional Chinese medicines. The results provide a theoretical basis for a broader clinical application of XDD-YQP.

Effect of in vitro gastro-intestinal digestion on the phenolic composition and antioxidant capacity of Burdock roots at different harvest time

The current study aimed to evaluate how the harvest time affects the phenolic composition in Burdock root flours (BRF) and how these phenolics are influenced by the gastro-intestinal digestive environment. Burdock roots were harvested in 2020 in Jiangsu Province in June (B1), July (B2) and August (B3). The main phenolic, 5-O-caffeoylquinic acid (5-CQA) decreased after in vitro digestion from 1.14 to 0.22 mg/g (B1 < B2 < B3). Total phenolic content of BRF was 61% lower after in vitro digestion whereas 5-CQA bioaccessibility remained at about 60%. Twelve other phenolic compounds were tentatively identified after in vitro digestion. An average reduction in antioxidant capacity of 27% and 10% was observed for DPPH and ABTS, respectively. In conclusion, data demonstrated that phenolic composition, bioaccessibility and antioxidant capacity of Burdock roots harvested at different times were subject to the influence of in vitro gastrointestinal digestion.

Polyphenols from Arctium lappa L ameliorate doxorubicin-induced heart failure and improve gut microbiota composition in mice

In this study, the ameliorative effect of purified polyphenols from Arctium lappa L (ALPP) on doxorubicin (DOX)-induce heart failure was investigated. Results indicated that ALPP pretreatment significantly reduced the activities of casein kinase and lactate dehydrogenase, lowered the levels of inflammatory indexes (TNF-α and NO), and alleviated antioxidant stress in DOX-induce mice, thus leading to a reduced heart failure syndrome. In addition, according to 16s high-throughput sequencing, the increased abundance of Lactobacillaceae, Muribaculaceae, and Ruminococcaceae and the decreased abundance of Proteobacteria, Enterobacteriaee, and Escherichia_Shigella were observed in ALPP treatment group. ALPP could significantly enhance the abundance of bacteria producing short chain fatty acids (SCFAs) and then promote the increase of SCFAs. Consequently, ALPP might be a therapeutic alternative in the treatment of DOX-induced heart failure. PRACTICAL APPLICATIONS: The effect of Arctium lappa L (ALPP) on doxorubicin (DOX)-induced heart failure was investigated. It provided experimental basis for further studies on the biological activity of polyphenols from ALPP. The results demonstrated that ALPP could significantly ameliorate DOX-induced heart failure and improve the gut microbiota composition. The obtained results could provide the potential application of ALPP as an alternative therapy for heart failure in the functional food industry.

Effect of Drying Methods on Volatile Compounds of Burdock (Arctium lappa L.) Root Tea as Revealed by Gas Chromatography Mass Spectrometry-Based Metabolomics

Burdock (Arctium lappa L.) is one of the nutritional foods widely planted in many countries. Dried burdock root (BR) is available as a herbal tincture and tea in many Asian countries with good flavor and taste. In this study, the volatile components in dried BR were identified and the effects of different drying methods on the volatile components were investigated by HS-GC-MS method. A total of 49 compounds were identified. Different drying methods including hot-air drying (HD, at 50, 60, 70, and 80 °C), vacuum drying (VD, at 50, 60, 70, and 80 °C), sunlight drying (SD), natural drying (ND), and vacuum freeze drying (VFD) were evaluated by HS-GC-MS-based metabolomics method. Results showed that different drying methods produced different effects on the volatile compounds. It was observed that 2,3-pentanedione, 1-(1H-pyrrol-2-yl)-ethanone, furfural, and heptanal were detected at higher concentrations in HD 80 and VD 70. The traditional HD and SD methods produced more flavor substances than VFD. The BR treated by the VFD method could maintain the shape of the fresh BR pieces while HD50 and VD80 methods could maintain the color of fresh BR pieces. These findings could help better understand the flavor of the corresponding processed BR and provide a guide for the drying and processing of BR tea.

Arctium lappa and Arctium tomentosum, Sources of Arctii radix: Comparison of Anti-Lipoxygenase and Antioxidant Activity as well as the Chemical Composition of Extracts from Aerial Parts and from Roots

Arctium lappa is a weed used in traditional medicine in the treatment of skin inflammation and digestive tract diseases. Arctium tomentosum is used in folk medicine interchangeably with Arctium lappa and, according to European Medicines Agency (EMA) monography, provides an equal source of Arctii radix (Bardanae radix), despite the small amount of research confirming its activity and chemical composition. The aim of the study was the comparison of the anti-lipoxygenase and the antioxidant activity, scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion (O₂^•−), and hydrogen peroxide (H₂O₂), of 70 % (v/v) ethanolic extracts from the aerial parts and the roots of Arctium lappa and Arctium tomentosum. In the tested extracts, the total polyphenols content and the chemical composition, analyzed with the HPLC–DAD–MSⁿ method, were also compared. The extracts were characterized by strong antioxidant properties, but their ability to inhibit lipoxygenase activity was rather weak. A correlation between the content of polyphenolic compounds and antioxidant activity was observed. The extracts from A. lappa plant materials scavenged reactive oxygen species more strongly than the extracts from A. tomentosum plant materials. Moreover, the extracts from A. lappa plant materials were characterized by the statistically significantly higher content of polyphenolic compounds.

Current Advances in Naturally Occurring Caffeoylquinic Acids: Structure, Bioactivity, and Synthesis

Caffeoylquinic acids (CQAs) are a broad class of secondary metabolites that have been found in edible and medicinal plants from various families. It has been 100 years since the discovery of chlorogenic acid in 1920. In recent years, a number of naturally derived CQAs have been isolated and structurally elucidated. Accumulated evidence demonstrate that CQAs have a wide range of biological activities, such as antioxidation, antibacterial, antiparasitic, neuroprotective, anti-inflammatory, anticancer, antiviral, and antidiabetic effects. Up to date, some meaningful progresses on the biosynthesis and total synthesis of CQAs have also been made. Therefore, it is necessary to comprehensively summarize the structure, biological activity, biosynthesis, and chemical synthesis of CQAs. This review provides extensive coverage of naturally occurring CQAs discovered from 1990 until 2020. Modern isolation techniques, chemical data (including structure, biosynthesis, and total synthesis), and bioactivity are summarized. This would be helpful for further research of CQAs as potential pharmaceutical agents.

Isolation, structure elucidation and neuroprotective effects of caffeoylquinic acid derivatives from the roots of Arctium lappa L

Five undescribed caffeoylquinic acid derivatives (CQAs), along with fifteen known CQAs, were isolated from the roots of Arctium lappa L.(burdock). The chemical structures of compounds were determined using extensive spectroscopic analyses, including UV, IR, NMR and MS. Further in vitro bioactive investigation demonstrated the neuroprotective effects of these compounds against the neurotoxicity of hydrogen peroxide (H₂O₂) and N-methyl-D-aspartate (NMDA). 1,3,5-tri-O-caffeoylquinic acid and 1,4,5-tri-O-caffeoylquinic acid significantly reduced H₂O₂-induced human neuroblastoma SH-SY5Y cell death with concentration for 50% of maximal effect (EC₅₀) values of 17.3 and 19.3 μM. Meanwhile, 3,5-di-O-caffeoyl-1-O-maloylquinic acid displayed protective effect against NMDA-induced cell injury with EC₅₀ values of 18.4 μM. Overall, the more caffeoyl, the better the antioxidant activity, while the maloyl-containing compounds had better anti-NMDA activity.

Arctium Species Secondary Metabolites Chemodiversity and Bioactivities

Arctium species are known for a variety of pharmacological effects due to their diverse volatile and non-volatile secondary metabolites. Representatives of Arctium species contain non-volatile compounds including lignans, fatty acids, acetylenic compounds, phytosterols, polysaccharides, caffeoylquinic acid derivatives, flavonoids, terpenes/terpenoids and volatile compounds such as hydrocarbons, aldehydes, methoxypyrazines, carboxylic and fatty acids, monoterpenes and sesquiterpenes. Arctium species also possess bioactive properties such as anti-cancer, anti-diabetic, anti-oxidant, hepatoprotective, gastroprotective, antibacterial, antiviral, antimicrobial, anti-allergic, and anti-inflammatory effects. This review aims to provide a complete overview of the chemistry and biological activities of the secondary metabolites found in therapeutically used Arctium species. Summary of pharmacopeias and monographs contents indicating the relevant phytochemicals and therapeutic effects are also discussed, along with possible safety considerations.

Semi-Preparative Separation of 10 Caffeoylquinic Acid Derivatives Using High Speed Counter-Current Chromatogaphy Combined with Semi-Preparative HPLC from the Roots of Burdock (Arctium lappa L.)

Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1–3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3-O-caffeoylquinic acid (32.7 mg, 95.7%), 1,5-O- dicaffeoylquinic acid (4.3 mg, 97.2%), 3-O-caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3-O-dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5-O-dicaffeoyl-3-O-(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5-O-dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5-O-dicaffeoyl-3-O-succinylquinic acid (8.7 mg, 93.4%), and 1,5-O-dicaffeoyl-4-O-succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4-O-dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5-O-dicaffeoyl-3-O-succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

Antioxidative and Anti-Melanogenic Activities of Bamboo Stems (Phyllostachys nigra variety henosis) via PKA/CREB-Mediated MITF Downregulation in B16F10 Melanoma Cells

Phyllostachys nigra var. henosis, a domestic bamboo species, has been attracting much attention; its bioactive compounds (especially in the leaf) show antioxidant, anti-inflammatory, and anti-obesity activities. Little information is available on the antioxidative and anti-melanogenetic activities of the bioactive compounds in bamboo stems. The anti-melanogenic and antioxidative activities of the EtOAc fraction (PN3) of a P. nigra stem extract were investigated in a cell-free system and in B16F10 melanoma cells. PN3 consisted of a mixture of flavonoids, such as catechin, chlorogenic acid, caffeic acid, and p-coumaric acid. The antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)), and hydroxyl radical scavenging) was evaluated, as well as the inhibition of reactive oxygen species (ROS) produced by the Fenton reaction. PN3 showed in vitro tyrosinase inhibition activity with the half maximal inbihitory concentration (IC₅₀) values of 240 μg/mL, and in vivo cytotoxic concentration ranges > 100 μg/mL. The protein expression levels and mRNA transcription levels of TYR, TRP-1, and MITF were decreased in a dose-dependent manner by the treatment with PN3. PN3 interfered with the phosphorylation of intracellular protein kinase A (PKA)/cAMP response element-binding protein (CREB), demonstrating potent anti-melanogenic effects. PN3 could inhibit PKA/CREB and the subsequent degradation of microphthalmia-associated transcription factor (MITF), resulting in the suppression of melanogenic enzymes and melanin production, probably because of the presence of flavonoid compounds. These properties make it a candidate as an additive to whitening cosmetics.

Chlorogenic acids and the acyl-quinic acids: discovery, biosynthesis, bioavailability and bioactivity

This review is focussed upon the acyl-quinic acids, the most studied group within theca.400 chlorogenic acids so far reported.

Leaf parts from Greek artichoke genotypes as a good source of bioactive compounds and antioxidants

Leaf blades had higher antioxidant activity and total phenolic compound content than midribs and petioles.

Synthesis, Structure, and Tandem Mass Spectrometric Characterization of the Diastereomers of Quinic Acid

(-)-Quinic acid possess eight possible stereoisomers, which occur both naturally and as products of thermal food processing. In this contribution, we have selectively synthesized four isomers, namely, epi-quinic acid, muco-quinic acid, cis-quinic acid, and scyllo-quinic acid, to develop a tandem LC-MS method identifying all stereoisomeric quinic acids. Four derivatives have been unambiguously characterized by single-crystal X-ray crystallography. The missing diastereomers of quinic acid were obtained by nonselective isomerization of (-)-quinic acid using acetic acid/concentrated H2SO4 allowing chromatographic separation and assignment of all diastereomers of quinic acid. We report for the first time that a full set of stereoisomers are reliably distinguishable on the basis of their tandem mass spectrometric fragment spectra as well as their elution order. A rationale for characteristic fragmentation mechanisms is proposed. In this study, we also observed that muco-quinic acid, scyllo-quinic acid, and epi-quinic acid are present in hydrolyzed Guatemalan roasted coffee sample as possible products of roasting.

Antioxidant Capacities and Analysis of Phenolic Compounds in Three Endemic Nolana Species by HPLC-PDA-ESI-MS

The antioxidant features, polyphenolic composition and chromatographic fingerprints of the aerial parts from three Chilean endemic plants from the Paposo Valley located on the cost of the Atacama Desert were investigated for the first time using high pressure liquid chromatography coupled with photodiode array detector and electrospray ionization mass analysis (HPLC-PDA-ESI-MS) and spectroscopic methods. The phenolic fingerprints obtained for the plants were compared and correlated with the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP) and quantification of the total content of phenolics and flavonoids measured by spectroscopic methods. Thirty phenolics were identified for the first time for these species, mostly phenolic acids, flavanones, flavonols and some of their glycoside derivatives, together with three saturated fatty acids (stearic, palmitic and arachidic acids). Nolana ramosissima showed the highest antioxidant activity (26.35 ± 1.02 μg/mL, 116.07 ± 3.42 μM Trolox equivalents/g dry weight and 81.23% ± 3.77% of inhibition in the DPPH, FRAP and scavenging activity (SA) assays, respectively), followed by N. aplocaryoides (85.19 ± 1.64 μg/mL, 65.87 ± 2.33 μM TE/g DW and 53.27% ± 3.07%) and N. leptophylla (124.71 ± 3.01, 44.23 ± 5.18 μM TE/g DW and 38.63% ± 1.85%).

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.

Identification and characterisation of the phenolics of Ilex glabra L. Gray (Aquifoliaceae) leaves by liquid chromatography tandem mass spectrometry

The phenolics of the leaves of Ilex glabra L. Gray (Aquifoliaceae) were investigated qualitatively by LC-MS(n). Thirty-two phenolics were detected and characterised 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 fifteen of them were not reported previously in nature. For the positive identification of phenolic glucosides by LC-MS(n) a series of authentic standards and experiments were carried out. This is the first report of a full characterisation of 3,4-dihydroxybenzoyl glucosides, 3,4-dihydroxybenzyl glucosides, 4-hydroxybenzoyl glucosides, chlorogenic acid glucosides and vanillic acid glucosides by LC-MS(2-4).

Chemical analysis and antihyperglycemic activity of an original extract from burdock root (Arctium lappa)

In the present study, we obtained a dried burdock root extract (DBRE) rich in caffeoylquinic acids derivatives. We performed the chemical characterization of DBRE and explored its antihyperglycemic potential in both in vitro and in vivo experiments. Chemical analysis of DBRE using LC-MS and GC-MS revealed the presence of a great majority of dicaffeoylquinic acid derivatives (75.4%) of which 1,5-di-O-caffeoyl-4-O-maloylquinic acid represents 44% of the extract. In the in vitro experiments, DBRE is able to increase glucose uptake in cultured L6 myocytes and to decrease glucagon-induced glucose output from rat isolated hepatocytes together with a reduction of hepatic glucose 6-phosphatase activity. DBRE did not increase insulin secretion in the INS-1 pancreatic β-cell line. In vivo, DBRE improves glucose tolerance both after intraperitoneal and oral subchronic administration. In conclusion, our data demonstrate that DBRE constitutes an original set of caffeoylquinic acid derivatives displaying antihyperglycemic properties.

Comparison of cytotoxic and anti-platelet activities of polyphenolic extracts from Arnica montana flowers and Juglans regia husks

Polyphenolic compounds of plant origin are well known to be beneficial to human health: they exert protective effects on haemostasis and have a particular influence on blood platelets. However, the anti-platelet properties of polyphenolic compounds observed so far have not been weighed against their potential cytotoxic action against platelets. The aim of this study was to demonstrate that anti-platelet and cytotoxic effects on blood platelets may interfere and therefore, may often lead to confusion when evaluating the properties of plant extracts or other agents towards blood platelets. The anti-platelet and cytotoxic in vitro effects of plant extracts obtained from the husks of walnuts (J. regia) and flowers of arnica (A. montana) on platelet reactivity and viability were examined. Platelet function was assessed using standard methods (flow cytometry: P-selectin expression, activation of GPIIbIIIa complex, vasodilator-stimulated phosphoprotein, VASP index; turbidimetric and impedance aggregometry) and newly set assays (flow cytometric monitoring of platelet cytotoxicity). The results reveal that none of the studied plant extracts demonstrated cytotoxicity towards blood platelets. The phenolic acid-rich extract of A. montana (7.5 and 15 µg/ml) significantly reduced the ADP-induced aggregation in both whole blood and PRP, and decreased the platelet reactivity index (PRI; VASP phosphorylation) in whole blood, while showing excellent antioxidant capacity. The extract of J. regia husks significantly reduced ADP-induced platelet aggregation in whole blood when applied at 7.5 µg/ml, and only slightly decreased the PRI at 15 µg/ml. Both examined extracts suppressed platelet hyper-reactivity, and such influence did not interfere with cytotoxic effects of the extracts. Thus, its high polyphenol content, excellent antioxidant capacity and distinct anti-platelet properties, in combination with its lack of toxicity, make the extract of A. montana flowers a possible candidate as an anti-platelet agent or a compounding diet supplement.

Identification and characterization of the phenolic glycosides of Lagenaria siceraria Stand. (bottle gourd) fruit by liquid chromatography-tandem mass spectrometry

Bottle gourd, Lagenaria siceraria Stand. (Cucurbitaceae), fruit is used in folk medicines and for culinary purposes in Asia. The phenolics of bottle gourd fruit were investigated qualitatively by LC-MS(n). Twenty-two phenolic glycosides were detected and characterized on the basis of their unique fragmentation pattern in the negative ion mode tandem MS spectra. Twenty of them were extracted for the first time from this source, and twelve of them have not been reported previously in nature. It was also possible to distinguish between the individual classes of isobaric phenolic glycosides by tandem and high-resolution mass spectrometry. In this study we also discuss the mass spectrometric fragmentation mechanism of 6-(hydroxycinnamoyl)glucoses. This is the first report of the full characterization of phenolic glycosides of bottle gourd fruit by LC-MS²⁻⁴.

Identification of phenolic compounds in plum fruits (Prunus salicina L. and Prunus domestica L.) by high-performance liquid chromatography/tandem mass spectrometry and characterization of varieties by quantitative phenolic fingerprints

Plums (Prunus domestica L. and Prunus salicina L.) are edible fruits mostly consumed in America, China, and Europe. We have used LC-MS(n) to detect and characterize the phenolic compounds in plum varieties. Forty-one phenolics were detected comprising caffeoylquinic acids, feruloylquinic acid, p-coumaroylquinic acids, methyl caffeoylquinates, methyl p-coumaroylquinate, caffeoylshikimic acids, catechin, epicatechin, rutin, esculin, quercetin, quercetin-3-O-hexosides, dimeric proanthocyanidins, trimeric proanthocyanidins, caffeoyl-glucoside, feruloyl-glucoside, p-coumaroyl-glucoside, vanillic acid-glucosides, 3,4-dihydroxybenzoyl-glucoside, quercetin-3-O-pentosides, quercetin-3-O-rhamnoside, quercetin-pentoside-rhamnosides, and 3-p-methoxycinnamoylquinic acid. This is the first time when 3-p-methoxycinnamoylquinic acid is reported in nature. Chlorogenic acids and proanthocyanidins were the major phenolics present in plums. Furthermore, HPLC with DAD and chemical reaction detection was used to generate quantitative phenolic fingerprints from the fruit flesh of 33 plum varieties. The predominant compound was 3-caffeoylquinic acid in nearly all varieties studied; generally, however, the qualitative and quantitative profiles showed high diversity even among closely related progenies.

Milk whey protein modification by coffee-specific phenolics: effect on structural and functional properties

A suitable vehicle for integration of bioactive plant constituents is proposed. It involves modification of proteins using phenolics and applying these for protection of labile constituents. It dissects the noncovalent and covalent interactions of β-lactoglobulin with coffee-specific phenolics. Alkaline and polyphenol oxidase modulated covalent reactions were compared. Tryptic digestion combined with MALDI-TOF-MS provided tentative allocation of the modification type and site in the protein, and an in silico modeling of modified β-lactoglobulin is proposed. The modification delivers proteins with enhanced antioxidative properties. Changed structural properties and differences in solubility, surface hydrophobicity, and emulsification were observed. The polyphenol oxidase modulated reaction provides a modified β-lactoglobulin with a high antioxidative power, is thermally more stable, requires less energy to unfold, and, when emulsified with lutein esters, exhibits their higher stability against UV light. Thus, adaptation of this modification provides an innovative approach for functionalizing proteins and their uses in the food industry.

Identification of phenolic constituents in Cichorium endivia var. crispum and var. latifolium salads by high-performance liquid chromatography with diode array detection and electrospray ioniziation tandem mass spectrometry

Chicory is a widely consumed vegetable and a source of phenolic compounds. Phenolic acid and flavonoid derivatives were identified in Cichorium endivia var. crispum and var. latifolium and fully characterized using complementary information from two different high-performance liquid chromatography detectors, diode array and mass spectrometer, in positive and negative modes. We describe about 40 phenolic compounds, some of which have never previously been reported in these plants, such as hydroxycinnamic acid derivatives (i.e., different mono- and dicaffeoylquinic acid isomers) and mono- and diglycosides of quercetin, kaempferol, and myricetin (differing also by the glycosylation site). These data provide a contribution to a more exhaustive identification of phenolic compounds in C. endivia vegetables.

Investigating the chemical changes of chlorogenic acids during coffee brewing: conjugate addition of water to the olefinic moiety of chlorogenic acids and their quinides

Coffee is one of the most popular and consumed beverages in the world and is associated with a series of benefits for human health. In this study we focus on the reactivity of chlorogenic acids, the most abundant secondary metabolites in coffee, during the coffee brewing process. We report on the hydroxylation of the chlorogenic acid cinnamoyl substituent by conjugate addition of water to form 3-hydroxydihydrocaffeic acid derivatives using a series of model compounds including monocaffeoyl and dicaffeoylquinic acids and quinic acid lactones. The regiochemistry of conjugate addition was established based on targeted tandem MS experiments. Following conjugate addition of water a reversible water elimination yielding cis-cinnamoyl derivatives accompanied by acyl migration products was observed in model systems. We also report the formation of all of these derivatives during the coffee brewing process.

Ethanolic extract of roots from Arctium lappa L. accelerates the healing of acetic acid-induced gastric ulcer in rats: Involvement of the antioxidant system

We evaluate the curative efficacy of the ethanolic extract (EET) of roots from Arctium lappa (bardana) in healing of chronic gastric ulcers induced by 80% acetic acid in rats and additionally studies the possible mechanisms underlying this action. Oral administration of EET (1, 3, 10 and 30mg/kg) reduced the gastric lesion area in 29.2%, 41.4%, 59.3% and 38.5%, respectively, and at 10mg/kg promoted significant regeneration of the gastric mucosa, which was confirmed by proliferating cell nuclear antigen immunohistochemistry. EET (10mg/kg) treatment did not increase the gastric mucus content but restored the superoxide dismutase activity, prevented the reduction of glutathione levels, reduced lipid hydroperoxides levels, inhibited the myeloperoxidase activity and reduced the microvascular permeability. In addition, EET reduced the free radical generation and increased scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals in vitro. Furthermore, intraduodenal EET (10 and 30mg/kg) decreased volume and acidity of gastric secretion. Total phenolic compounds were high in EET (Folin-Ciocalteau assay) and the analysis by liquid chromatography-mass spectrometry revealed that the main compounds present in EET were a serie of hydroxycinnamoylquinic acid isomers. In conclusion, these data reveal that EET promotes regeneration of damaged gastric mucosa, probably through its antisecretory and antioxidative mechanisms.

Small-RNA deep sequencing reveals Arctium tomentosum as a natural host of Alstroemeria virus X and a new putative Emaravirus

BACKGROUND

Arctium species (Asteraceae) are distributed worldwide and are used as food and rich sources of secondary metabolites for the pharmaceutical industry, e.g., against avian influenza virus. RNA silencing is an antiviral defense mechanism that detects and destroys virus-derived double-stranded RNA, resulting in accumulation of virus-derived small RNAs (21-24 nucleotides) that can be used for generic detection of viruses by small-RNA deep sequencing (SRDS).

METHODOLOGY/PRINCIPAL FINDINGS

SRDS was used to detect viruses in the biennial wild plant species Arctium tomentosum (woolly burdock; family Asteraceae) displaying virus-like symptoms of vein yellowing and leaf mosaic in southern Finland. Assembly of the small-RNA reads resulted in contigs homologous to Alstroemeria virus X (AlsVX), a positive/single-stranded RNA virus of genus Potexvirus (family Alphaflexiviridae), or related to negative/single-stranded RNA viruses of the genus Emaravirus. The coat protein gene of AlsVX was 81% and 89% identical to the two AlsVX isolates from Japan and Norway, respectively. The deduced, partial nucleocapsid protein amino acid sequence of the emara-like virus was only 78% or less identical to reported emaraviruses and showed no variability among the virus isolates characterized. This virus--tentatively named as Woolly burdock yellow vein virus--was exclusively associated with yellow vein and leaf mosaic symptoms in woolly burdock, whereas AlsVX was detected in only one of the 52 plants tested.

CONCLUSIONS/SIGNIFICANCE

These results provide novel information about natural virus infections in Acrtium species and reveal woolly burdock as the first natural host of AlsVX besides Alstroemeria (family Alstroemeriaceae). Results also revealed a new virus related to the recently emerged Emaravirus genus and demonstrated applicability of SRDS to detect negative-strand RNA viruses. SRDS potentiates virus surveys of wild plants, a research area underrepresented in plant virology, and helps reveal natural reservoirs of viruses that cause yield losses in cultivated plants.