High-resolution genome mapping and functional dissection of chlorogenic acid production in Lonicera maackii.

Amur honeysuckle (Lonicera maackii) is a widely used medicinal plant of the Caprifoliaceae family that produces chlorogenic acid. Research on this plant mainly focuses on its ornamental value and medicinal compounds, but a reference genome sequence and molecular resources for accelerated breeding are currently lacking. Herein, nanopore sequencing and high-throughput chromosome conformation capture (Hi-C) allowed a chromosome-level genome assembly of L. maackii (2n = 18). A global view of the gene regulatory network involved in the biosynthesis of chlorogenic acid and the dynamics of fruit coloration in L. maackii was established through metabolite profiling and transcriptome analyses. Moreover, we identified the genes encoding hydroxycinnamoyl-CoA quinate transferase (LmHQT) and hydroxycinnamoyl-CoA shikimic/quinate transferase (LmHCT), which localized to the cytosol and nucleus. Heterologous overexpression of these genes in Nicotiana benthamiana leaves resulted in elevated chlorogenic acid contents. Importantly, HPLC analyses revealed that LmHCT and LmHQTs recombinant proteins modulate the accumulation of chlorogenic acid (CGA) using quinic acid and caffeoyl CoA as substrates, highlighting the importance of LmHQT and LmHCT in CGA biosynthesis. These results confirmed that LmHQTs and LmHCT catalyze the biosynthesis of CGA in vitro. The genomic data presented in this study will offer a valuable resource for the elucidation of CGA biosynthesis and facilitating selective molecular breeding.

Investigation of the phytochemical composition and remedial effects of southern grape hyacinth (Muscari neglectum Guss. ex Ten.) plant extract against carbon tetrachloride-induced oxidative stress in rats.

We aimed to determine the phytochemical contents of the aerial part M. neglectum aerial part (MAP) and M. neglectum bulb (MB) ethanolic extract of Muscari neglectum and to investigate their protective effects on gastric damage induced by carbon tetrachloride (CCl4) in rats. After the toxicity testing, 42 female Wistar albino rats were divided into 7 groups, Control, MAP, MB, CCl4, CCl4 + MAP, CCl4 + MB, and CCl4 + Silymarin groups. At the end of the experiment, the serum biochemical parameters, antioxidant defense enzymes, and malondialdehyde (MDA) contents in the stomach tissue were evaluated to determine the antioxidant role of the M. neglectum extracts. According to the gas chromatography-mass spectroscopy, fatty acid analysis, octadecadienoic, and 9,12,15 octadecatrienoic fatty acids were found as major fatty acids in the MAP, whereas 9,12 octadecadienoic and octadecanoic acids were the major fatty acids in the MB. According to the liquid chromatography-tandem mass spectrometry, quinic acid, fumaric acid, gentisic acid, caffeic acid, kaempferol, and apigenin were found in the MAP, while quinic acid, fumaric acid, caffeic acid, and kaempferol were found in the MB. The total phenolic and flavonoid contents in the extract were determined in the MAP and MB. The MAP and MB extracts generally caused a statistically significant decrease in the MDA content and increase in the antioxidant parameters in the stomach tissue. It was concluded that MAP and MB extracts may have antioxidant and gastric protective effects due to the phytochemical content of M. neglectum.HighlightsAccording to LC-MS/MS results, quinic acid, fumaric acid, chemferol, apigenin, and caffeic acid were determined as major compounds in M. neglectum extracts.According to GC-MS results, octadecadienoic, octadecatrienoic, and octadecanoic methyl esters were the major fatty acids of the M. neglectum extracts.The M. neglectum extracts regulated the levels of stomach damage and biochemical parameters.The M. neglectum extracts extract might have pharmaceutical-nutritional potential.

Protective effect of D-(-)-quinic acid as food supplement in modulating AMP-activated protein kinase signalling pathway activation in HFD induced obesity.

BACKGROUND: Dietary quinic acid given as the nutritional supplement, which may leads to tryptophan and nicotinamide production in the intestinal tract and NAD+ precursor which can prevent from the negative consequences of high fat diet (HFD) consumption. OBJECTIVE: The present study was designed to assess in vivo and in vitro effect of D-(-)-Quinic acid in high-fat diet induced hyperlipidemia in mice. MATERIAL AND METHODS: Thirty six albino mice were randomly divided in six groups and each group had six mice. Group I, controlled mice given normal pellet diet, Group-II mice, administered with high fat diet (HFD), Group-III mice given standard drug, Atorvastatin (20 mg/kg, p.o.) along with HFD to mice and Group IV, V and VI mice received D-(-)-Quinic acid at a dose of 75, 150 and 300 mg/kg, respectively in separate group along with HFD to mice. After completion of trial (49 days) the animals were sacrificed and evaluated for body weight, organ fat pad weight, and changes in weight of liver, heart and kidney and also for biochemical parameters, expression of adipogenic and inflammation markers in adipose tissues, and histology examination of liver tissue. RESULTS: In vitro testing results showed, D-(-)-Quinic acid potentially inhibit α-glucosidase enzyme activity as compared to acarbose. The D-(-)-Quinic acid showed significant hypolipidemic activity by decreasing the increased level of cholesterol, triglyceride level, LDL, VLDL and other hepatic parameters like SGOT and SGPT in serum. D-(-)-Quinic acid reduces the mRNA expression level of PPAR-γ2, TNF-α, IL-1ß and IL-6 in adipose tissue in hyperlipidemic mice.

Novel Quinic Acid Glycerates from Tussilago farfara Inhibit Polypeptide GalNAc-Transferase.

The discovery of a bioactive inhibitor tool for human polypeptide N-acetylgalactosaminyl transferases (GalNAc-Ts), the initiating enzyme for mucin-type O-glycosylation, remains challenging. In the present study, we identified an array of quinic acid derivatives, including four new glycerates (1-4) from Tussilago farfara, a traditional Chinese medicinal plant, as active inhibitors of GalNAc-T2 using a combined screening approach with a cell-based T2-specific sensor and purified enzyme assay. These inhibitors dose-dependently inhibited human GalNAc-T2 but did not affect O-linked N-acetylglucosamine transferase (OGT), the other type of glycosyltransferase. Importantly, they are not cytotoxic and retain inhibitory activity in cells lacking elongated O-glycans, which are eliminated by the CRISPR/Cas9 gene editing tool. A structure-activity relationship study unveiled a novel quinic acid-caffeic acid conjugate pharmacophore that directs inhibition. Overall, these new natural product inhibitors could serve as a basis for developing an inhibitor tool for GalNAc-T2.

Caffeoylquinic acids: chemistry, biosynthesis, occurrence, analytical challenges, and bioactivity.

Caffeoylquinic acids (CQAs) are specialized plant metabolites we encounter in our daily life. Humans consume CQAs in mg-to-gram quantities through dietary consumption of plant products. CQAs are considered beneficial for human health, mainly due to their anti-inflammatory and antioxidant properties. Recently, new biosynthetic pathways via a peroxidase-type p-coumaric acid 3-hydroxylase enzyme were discovered. More recently, a new GDSL lipase-like enzyme able to transform monoCQAs into diCQA was identified in Ipomoea batatas. CQAs were recently linked to memory improvement; they seem to be strong indirect antioxidants via Nrf2 activation. However, there is a prevalent confusion in the designation and nomenclature of different CQA isomers. Such inconsistencies are critical and complicate bioactivity assessment since different isomers differ in bioactivity and potency. A detailed explanation regarding the origin of such confusion is provided, and a recommendation to unify nomenclature is suggested. Furthermore, for studies on CQA bioactivity, plant-based laboratory animal diets contain CQAs, which makes it difficult to include proper control groups for comparison. Therefore, a synthetic diet free of CQAs is advised to avoid interferences since some CQAs may produce bioactivity even at nanomolar levels. Biotransformation of CQAs by gut microbiota, the discovery of new enzymatic biosynthetic and metabolic pathways, dietary assessment, and assessment of biological properties with potential for drug development are areas of active, ongoing research. This review is focused on the chemistry, biosynthesis, occurrence, analytical challenges, and bioactivity recently reported for mono-, di-, tri-, and tetraCQAs.

Ethylene Induction of Non-Enzymatic Metabolic Antioxidants in Matricaria chamomilla.

Phytochemical investigations of Matricaria chamomilla L. (Asteraceae) stated the presence of several compounds with an established therapeutic and antioxidant potential. The chamomile non-enzymatic antioxidant system includes low molecular mass compounds, mainly polyphenols such as cinnamic, hydroxybenzoic and chlorogenic acids, flavonoids and coumarins. The objective of this work was to evaluate the role of the non-enzymatic antioxidant system after stimulation by ethylene in tetraploid chamomile plants. Seven days of ethylene treatment significantly increased the activity of phenylalanine ammonia-lyase, which influenced the biosynthesis of protective polyphenols in the first step of their biosynthetic pathway. Subsequently, considerable enhanced levels of phenolic metabolites with a substantial antioxidant effect (syringic, vanillic and caffeic acid, 1,5-dicaffeoylquinic acid, quercetin, luteolin, daphnin, and herniarin) were determined by HPLC-DAD-MS. The minimal information on the chlorogenic acids function in chamomile led to the isolation and identification of 5-O-feruloylquinic acid. It is accumulated during normal conditions, but after the excessive effect of abiotic stress, its level significantly decreases and levels of other caffeoylquinic acids enhance. Our results suggest that ethephon may act as a stimulant of the production of pharmaceutically important non-enzymatic antioxidants in chamomile leaves and thus, lead to an overall change in phytochemical content and therapeutic effects of chamomile plants, as well.

Bioavailability and metabolism of chlorogenic acids (acyl-quinic acids) in humans.

Acyl-quinic acids (chlorogenic acids) are produced by many plants, including fruits, vegetables, and herbal remedies, with coffee and maté particularly rich dietary sources. Epidemiological and intervention studies suggest that they can reduce the risk of developing type 2 diabetes and cardiovascular disease. This review addresses their metabolic handling after oral consumption to provide a mechanistic basis to explain their possible effects on health. Intact acyl-quinic acids are absorbed only to a small extent in the small intestine, but the cinnamic acids are efficiently absorbed after hydrolysis by either digestive or microbial enzymes in the colon. Metabolism results in phenolic conjugates in the blood and urine, but varying dependent on the acyl-quinic acid, and subject to significant interperson variability. The balance between hydrogenation and complete ß-oxidation of the cinnamic acids, both by liver and gut microbiota, determines the profile of metabolites. Pharmacokinetic data suggest that some metabolites are bound to human serum albumin and/or sequestered in tissues, and some exhibit biological activity in vitro, consistent with proposed protective action in vivo. Significant gaps in the literature include lack of plasma and urinary data for free-living individuals, and pharmacokinetic data for groups who consume coffee or maté at regular short intervals. Data are required for cis isomers. There is a critical need for precise urinary biomarkers of consumption of acyl-quinic acids, accounting for variability in individual metabolism and in beverage composition, thus facilitating better translation of urinary metabolite measurements into accurate coffee consumption data to improve the outcomes of future epidemiological and intervention studies.

Moderate consumption of a soluble green/roasted coffee rich in caffeoylquinic acids reduces cardiovascular risk markers: results from a randomized, cross-over, controlled trial in healthy and hypercholesterolemic subjects.

PURPOSE: Coffee is rich in bioactive compounds with health beneficial properties, with green coffee presenting higher phenol content than roasted. We evaluated the effects of regularly consuming realistic amounts of a green/roasted coffee blend on cardiovascular health-related biomarkers. METHODS: A randomized, cross-over, controlled study was carried out in 25 normocholesterolemic [total cholesterol (TC) < 200 mg/dL] and 27 hypercholesterolemic (TC 200-240 mg/dL) subjects. During 8 weeks, volunteers consumed 6 g/day of soluble green/roasted (35:65) coffee or a control beverage (water or an isotonic drink). Blood pressure, heart rate and body weight were monitored at the end of each intervention, and serum lipids [TC, HDL-C, LDL-C, VLDL-C, triglycerides and phospholipids], cytokines and chemokines (IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, IL-13, IL-17, G-CSF, GM-CSF, MCP-1, MIP-1ß, TNF-α, INF-γ), adhesion molecules (ICAM-1, VCAM-1), and C-reactive protein were measured. Plasma antioxidant capacity (FRAP, ORAC and ABTS methods), and lipid (malondialdehyde, MDA) and protein (carbonyl groups, CG) oxidation were also determined. RESULTS: Attending to the general lineal model of variance for repeated measures, after the green/roasted coffee intervention significant reductions in TC, LDL-C, VLDL-C and triglycerides levels (p = 0.006, 0.001, 0.003 and 0.017, respectively), and a significant group effect were observed (0.001, < 0.001, 0.019 and 0.027, respectively). Only within the hypercholesterolemic group, attending to the Bonferroni test, the aforementioned lipid parameters were significantly lower after regular green/roasted coffee intake compared to baseline values. Moreover, after the coffee stage, plasma antioxidant capacity improved, according to the increase in ORAC and FRAP values (p < 0.001 and p < 0.001, respectively) and decrease of MDA (p = 0.015) and CG (p < 0.001) levels, without differences between groups. Systolic (p = 0.001) and diastolic (p < 0.001) blood pressure, heart rate (p = 0.035), and body weight (p = 0.017) were reduced in both normo- and hypercholesterolemic groups. CONCLUSION: Regular consumption of moderate amounts of a soluble green/roasted (35:65) coffee blend may contribute to improve cardiovascular health in moderately hypercholesterolemic people, as reducing serum lipids, blood pressure and body weight effects, as well as increasing plasma antioxidant capacity, have been observed. Moreover, positive influences on blood pressure, body weight, and plasma antioxidant capacity were obtained in the healthy group. Therefore, incorporation of green coffee beans into the coffee brew can be recommended as part of a dietary strategy to protect from cardiovascular disease.

Comprehensive metabolite profiling in distinct chemotypes of Commiphora wightii.

Commiphora wightii (Arn.) Bhandari, known as guggul, produces a medicinally important gum resin which is used extensively by Ayurvedic physicians to treat various ailments. However, most of the studies on C. wightii have been limited to its gum resin. Comprehensive metabolic profiling of leaves, stem and gum resin samples was undertaken to analyse aqueous and non-aqueous metabolites from three distinct chemotypes (NBRI-101, NBRI-102 and NBRI-103) shortlisted from different agro-climatic zones. GC-MS, HPLC and NMR spectroscopy were used for comprehensive metabolomics. Multivariate analysis showed characteristic variation in quinic and citric acids, myo-inositol and glycine (aqueous metabolites) and 2,6-di-tert-butyl-phenol, trans-farnesol and guggulsterones (non-aqueous metabolites) amongst the three chemotypes. Quinic acid, citric acid and myo-ionositol were detected in substantial quantities from leaves and stem samples which provide opportunities for novel nutraceutical and pharmaceutical formulations. Quinic acid, from the leaves, was identified as a marker metabolite for early selection of high guggulsterones-yielding cultivars.

Hydrolysis of Dicaffeoylquinic Acids from Ilex kudingcha Happens in the Colon by Intestinal Microbiota.

Monocaffeoylquinic acids (mono-CQAs) can be hydrolyzed or metabolized by pancreatin, intestinal brush border esterase, and microbiota in the colon. Data about the conversion of dicaffeoylquinic acids (diCQAs) in digestion are scarce. The diCQA-rich fraction including 3,4-, 3,5-, and 4,5-diCQAs was prepared from Ilex kudingcha, and the conversion in simulated gastricintestine was investigated. Artificial saliva, gastric and pancreatic fluids, Caco-2 monolayer cells, and anaerobic fermentation model were utilized to mimic digestions of the oral cavity, stomach, small intestine, and colon in vitro. The results revealed that diCQAs remained intact in simulated saliva, gastric, and pancreatic fluids and within Caco-2 cells. In anaerobic fermentation with human fecal slurry, diCQAs were hydrolyzed to mono-CQAs and caffeic acid, which were further metabolized to caffeic acid and dihydrocaffeic acid, respectively. The hydrolysis of diCQAs depended on the chemical structures, carbohydrates in the culture medium, and microbial compositions. Our research demonstrated that hydrolysis of diCQAs happened in the colon by intestinal microbiota.

Development of Marker-Free Transgenic Potato Tubers Enriched in Caffeoylquinic Acids and Flavonols.

Potato (Solanum tuberosum L.) is a major crop worldwide that meets human economic and nutritional requirements. Potato has several advantages over other crops: easy to cultivate and store, cheap to consume, and rich in a variety of secondary metabolites. In this study, we generated three marker-free transgenic potato lines that expressed the Arabidopsis thaliana flavonol-specific transcriptional activator AtMYB12 driven by the tuber-specific promoter Patatin. Marker-free potato tubers displayed increased amounts of caffeoylquinic acids (CQAs) (3.35-fold increases on average) and flavonols (4.50-fold increase on average). Concentrations of these metabolites were associated with the enhanced expression of genes in the CQA and flavonol biosynthesis pathways. Accumulation of CQAs and flavonols resulted in 2-fold higher antioxidant capacity compared to wild-type potatoes. Tubers from these marker-free transgenic potatoes have therefore improved antioxidant properties.

Coffee Consumption and Melanoma: A Systematic Review and Meta-Analysis of Observational Studies.

BACKGROUND: Laboratory and animals studies have suggested a possible protective effect of coffee consumption on the development of melanoma. However, the results of epidemiological studies investigating this association have been inconclusive. OBJECTIVE: A systematic review and meta-analysis of published studies was conducted to evaluate any association between coffee consumption and melanoma. METHODS: Observational studies were searched for in MEDLINE, EMBASE, and the Cochrane Central Register from inception to September 1, 2015. The Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines were followed in conducting this study. RESULTS: We identified nine observational studies with a total of 927,173 study participants, of which 3787 had melanoma. With random-effects modeling, the pooled relative risks (RR) for melanoma among regular coffee drinkers was 0.75 (95 % confidence interval [CI] 0.63-0.89, p = 0.001) compared with controls. Visual inspection of a funnel plot suggested publication bias, although Egger's test (p = 0.981) delineated no small-study effects. The pooled relative risks for melanoma among decaffeinated coffee drinkers was, however, not statistically significant at 0.92 (95 % CI 0.82-1.05, p = 0.215). CONCLUSION: There is some evidence for the beneficial effects of regular coffee consumption on melanoma. More prospective cohort studies with systematic quantification of coffee consumption would be necessary to further elucidate this association.

Dicaffeoylquinic Acid-Enriched Fraction of Cichorium glandulosum Seeds Attenuates Experimental Type 1 Diabetes via Multipathway Protection.

Chicory has a major geographical presence in Europe and Asia. Cichorium glandulosum Boiss. et Huet, a genus Cichorium, is used for medicinal and food purposes in Asia. In this study, a dicaffeoylquinic acid-enriched fraction of C. glandulosum seeds n-BuOH fraction (CGSB) could ameliorate type 1 diabetes mellitus (T1DM) in streptozotocin (STZ)-induced diabetic mice with continuous administration for 2 weeks. CGSB treatment showed significantly higher plasma insulin levels but lower free fatty acids in adipose tissue and liver. Moreover, CGSB improved pancreatic islet mass. In vitro, different fractions of C. glandulosum seed (CGS) induced the differentiation of 3T3-L1 preadipocytes. The mRNA level for peroxisome proliferator-activated receptor alpha increased in high glucose treatment group in HepG2 cells, while CGSB significantly down-regulated the mRNA expression. The main compound of CGSB, 3,5-dicaffeoylquinic acid, was isolated and identified, which exhibited α-glucosidase inhibitory activity. These findings demonstrated that CGSB attenuated experimental T1DM via multipathway protection.

[Cloning and expression analysis of a hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferasegene(IiHCT) from Isatis indigotica].

Based on the transcriptome data, we cloned the open reading frame of IiHCT gene from Isatis indigotica, and then performed bioinformatic analysis of the sequence. Further, we detected expression pattern in specific organs and hairy roots treated methyl jasmonate( MeJA) by RT-PCR. The IiHCT gene contains a 1 290 bp open reading frame( ORF) encoding a polypeptide of 430 amino acids. The predicted isoelectric point( pI) was 5.7, a calculated molecular weight was about 47.68 kDa. IiHCT was mainly expressed in stem and undetectable in young root, leaf and flower bud. After the treatment of MeJA, the relative expression level of IiHCT increased rapidly. The expression level of IiHCT was the highest at 4 h and maintained two fold to control during 24 h. In this study, cloning of IiHCT laid the foundation for illustrating the biosynthesis mechanism of phenylpropanoids in I. indigotica.

Structure- and dose-absorption relationships of coffee polyphenols.

Chlorogenic acids (CGAs) from coffee have biological effects related to human health. Thus, specific data on their bioavailability in the upper gastrointestinal tract are of high interest, since some molecules are absorbed here and so are not metabolized by colonic microflora. Up to now, no data on structure-absorption relationships for CGAs have been published, despite this being the most consumed group of polyphenols in the western diet. To address this gap, we performed ex vivo absorption experiments with pig jejunal mucosa using the Ussing chamber model (a model simulating the mucosa and its luminal/apical side). The main coffee polyphenols, caffeoylquinic acid (CQA), feruloylquinic acid (FQA), caffeic acid (CA), dicaffeoylquinic acid (diCQA), and D-(-)-quinic acid (QA), were incubated in individual experiments equivalent to gut lumen physiologically achievable concentrations (0.2-3.5 mM). Identification and quantification were performed with HPLC-diode array detection and HPLC-MS/MS. Additionally, the presence of ABC-efflux transporters was determined by Western blot analysis. The percentages of initially applied CGAs that were absorbed through the jejunal pig mucosa were, in increasing order: diCQA, trace; CQA, ≈ 1%; CA, ≈ 1.5%; FQA, ≈ 2%; and QA, ≈ 4%. No differences were observed within the CGA subgroups. Dose-absorption experiments with 5-CQA suggested a passive diffusion (nonsaturable absorption and a linear dose-flux relationship) and its secretion was affected by NaN3 , indicating an active efflux. The ABC-efflux transporters MDR 1 and MRP 2 were identified in pig jejunal mucosa for the first time. We conclude that active efflux plays a significant role in CGA bioavailability and, further, that the mechanism of CGA absorption in the jejunum is governed by their physicochemical properties.

Medicinal flowers. XXXVIII. structures of acylated sucroses and inhibitory effects of constituents on aldose reducatase from the flower buds of Prunus mume.

The methanolic extract from the flower buds of Prunus mume, cultivated in Zhejiang province, China, showed an inhibitory effect on aldose reductase. From the methanolic extract, five new acylated sucroses, mumeoses F-J, were isolated together with 29 known compounds. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of the isolated compounds on aldose reductase were also investigated. Acylated quinic acid analogs, which are one of the major compounds of the flower buds of P. mume, were shown to substantially inhibit aldose reductase. In particular, mumeic acid-A was found to exhibit a potent inhibitory effect [IC50=0.4 µm].

Identification of the ortho-benzoquinone intermediate of 5-O-caffeoylquinic acid in vitro and in vivo: comparison of bioactivation under normal and pathological situations.

5-O-Caffeoylquinic acid (5-CQA) is one of the major bioactive ingredients in some Chinese herbal injections. Occasional anaphylaxis has been reported for these injections during their clinical use, possibly caused by reactive metabolites of 5-CQA. This study aimed at characterizing the bioactivation pathway(s) of 5-CQA and the metabolic enzyme(s) involved. After incubating 5-CQA with GSH and NADPH-supplemented human liver microsomes, two types of GSH conjugates were characterized: one was M1-1 from the 1,4-addition of GSH to ortho-benzoquinone intermediate; the other was M2-1 and M2-2 from the 1,4-addition of GSH directly to the α,ß-unsaturated carbonyl group of the parent. The formation of M1-1 was cytochrome P450 (P450)-mediated, with 3A4 and 2E1 as the principal catalyzing enzymes, whereas the formation of M2-1 and M2-2 was independent of NADPH and could be accelerated by cytosolic glutathione transferase. In the presence of cumene hydroperoxide, M1-1 formation increased 6-fold, indicating that 5-CQA can also be bioactivated by P450 peroxidase under oxidizing conditions. Furthermore, M1-1 could be formed by myeloperoxidase in activated human leukocytes, implying that 5-CQA bioactivation is more likely to occur under inflammatory conditions. This finding was supported by experiments on lipopolysaccharide-induced inflammatory rats, where a greater amount of M1-1 was detected. In S-adenosyl methionine- and GSH-supplemented human S9 incubations, M1-1 formation decreased by 80% but increased after tolcapone-inhibited catechol-O-methyltransferase (COMT) activity. In summary, the high reactivities of the ortho-benzoquinone metabolite and α,ß-unsaturated carbonyl group of 5-CQA to nucleophiles have been demonstrated. Different pathological situations and COMT activities in patients may alter the bioactivation extent of 5-CQA.

Content of antioxidative caffeoylquinic acid derivatives in field-grown Ligularia fischeri (Ledeb.) Turcz and responses to sunlight.

Ligularia fischeri (Ledeb.) Turcz, a commercial leafy vegetable, contains caffeoylquinic acid derivatives (CQAs) as major phenolic constituents. The HPLC chromatograms of leaf extracts collected from different areas in Korea showed a significant variation in CQA amount, and two tri-O-caffeoylquinic acids (triCQAs) were purified and structurally identified by NMR and MS from this plant. Radical scavenging activities among CQAs were found to be increased in proportion to the number of caffeoyl groups. Since this plant prefers damp and shady growth conditions, the effects of sunlight were investigated by growing plantlets in sunlight and shade for four weeks. Greater leaf thickness and higher phenolic contents were found for leaves grown in sunlight than in shade. Four major CQAs-5-mono-O-caffeoylquinic acid (5-monoCQA), and 3,4-, 3,5-, and 4,5-di-O-caffeoylquinic acid (diCQA)-were induced by solar irradiation, whereas the content of these compounds decreased steadily in shade leaves. The leaves of L. fischeri clearly showed adaptation responses to sunlight, and these characteristics can be exploited for cultivation of this plant for potential use as a nutraceutical and functional food.

Comparative analysis of caffeoylquinic acids and lignans in roots and seeds among various burdock (Arctium lappa) genotypes with high antioxidant activity.

Caffeoylquinic acids and lignans in the crude extracts of both roots and seeds from different burdock ( Arctium lappa L.) genotypes were simultaneously characterized and systematically compared by LC-MS and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS), and their antioxidant activities were also investigated. A total of 14 lignans were identified in burdock seeds and 12 caffeoylquinic acids in burdock roots. High levels of caffeoylquinic acids were also detected in burdock seeds, but only trace amounts of lignans were found in burdock roots. Burdock seeds contained higher concentrations of lignans and caffeoylquinic acids than burdock roots. Quantitative analysis of caffeoylquinic acids and lignans in roots and seeds of various burdock genotypes was reported for the first time. Great variations in contents of both individual and total phenolic compounds as well as antioxidant activities were found among different genotypes. Burdock as a root vegetable or medicinal plants possessed considerably stronger antioxidant activity than common vegetables and fruits.

New insights into an ancient antibrowning agent: formation of sulfophenolics in sodium hydrogen sulfite-treated potato extracts.

The effect of sodium hydrogen sulfite (S), used as antibrowning agent, on the phenolic profile of potato extracts was investigated. This extract was compared to one obtained in the presence of ascorbic acid (A). In the presence of A, two major compounds were obtained, 5-O-caffeoylquinic acid (5-CQA) and 4-O-caffeoyl quinic acid. With S, their 2'-sulfo-adducts were found instead, the structures of which were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Also, for minor caffeoyl derivatives and quercetin glycosides, the corresponding sulfo-adducts were observed. Feruloyl and sinapoyl derivatives were not chemically affected by the presence of S. Polyphenol oxidase (PPO) was thought to be responsible for the formation of the sulfo-adducts. This was confirmed by preparing 2'-sulfo-5-O-caffeoyl quinic acid in a model system using 5-CQA, sodium hydrogen sulfite, and PPO. This sulfo-adduct exhibited a small bathochromic shift (λmax 329 nm) as compared to 5-CQA (λmax 325 nm) and a strong hypochromic shift with an extinction coefficient of 9357±395 M(-1) cm(-1) as compared to 18494±196 M(-1) cm(-1), respectively. The results suggest that whenever S is used as an antibrowning agent, the O-quinone formed with PPO reacts with S to produce sulfo-O-diphenol, which does not participate in browning reactions.