Feruloylquinic Acids Research Articles

Revealing the spatial distribution of chlorogenic acids and sucrose across coffee bean endosperm by desorption electrospray ionization-mass spectrometry imaging

Endosperm tissue of cross-sectioned green arabica coffee beans was analyzed by the ambient ionization technique desorption electrospray ionization-mass spectrometry (DESI-MS) imaging and the spatial distribution of chlorogenic acids and sucrose across the bean endosperm was revealed. Quinic acid and feruloylquinic acid were located, preferably, in the hard external region of the endosperm, while caffeoylquinic acid was detected in high levels in the soft internal region. This non-homogeneous spatial distribution appears to be related to different functions of these distinct tissue regions. Sucrose was detected across the whole coffee bean endosperm. A damaged green coffee bean with holes caused by the coffee berry borer (Hypothenemus hampei) was also analyzed and increased levels of caffeoyl-sinapoylquinic acid and the unidentified m/z ion 535 were observed in the injured endosperm region compared to other regions. This new approach, of using DESI-MS imaging for coffee analysis, could help expand our knowledge about coffee chemistry and physiology.

In vitro studies on the stability in the proximal gastrointestinal tract and bioaccessibility in Caco-2 cells of chlorogenic acids from spent coffee grounds

Spent coffee grounds are a potential commercial source of substantial amounts of chlorogenic acids (CGAs). The aim of this study was to evaluate the stability of spent coffee CGAs using in vitro simulated gastroduodenal digestion and to investigate their potential absorption using an in vitro Caco-2 model of human small intestinal epithelium. During in vitro digestion, lactones were partially degraded while caffeoylquinic and feruloylquinic acids were much more stable. Transport and metabolism studies showed that 1% of the total CGAs were absorbed and transported from the apical to the basolateral side of a Caco-2 cell monolayer after 1 h. Lactones and coumaroylquinic acids showed the rate of highest absorption. Caco-2 cells possessed low metabolic activity. In conclusion, spent coffee extracts contain large amounts of CGAs, which remained bioaccessible across the intestinal barrier, albeit to a relatively low degree.

Traditional elderflower beverages: a rich source of phenolic compounds with high antioxidant activity.

Traditional elderflower beverages are very popular due to their pleasing taste and pro-health properties. Phenolics were quantified in three elderflower extracts (methanolic extraction and two water extracts prepared as fresh drinks according to local recipes) with HPLC-MS. Chromatographic patterns of methanolic and water extracts were quite similar; however, content levels of individual compounds differed between the two extraction solvents. Two feruloylquinic acids and two p-coumaroyl-caffeoylquinic acids and different flavonol glycosides have been identified in elderflowers for the first time. Hydroxycinnamic acids and flavonol glycosides were the major phenolic constituents in elderflowers. Methanolic extract contained higher levels of all phenolic groups compared to water-extracted samples. The yield of elderflower extracts depended on extract solution and time of extraction. Elderflower beverages were characterized by high total phenolic content (91.09 to 746.63 mg GAE/L). The results confirmed that elderflower beverages (sabesa, syrup) should be recommended as a good source of phenolics in human diet.

Phenolic profiling of the South American "Baylahuen" tea (Haplopappus spp., Asteraceae) by HPLC-DAD-ESI-MS.

The aerial parts of several Haplopappus species (Asteraceae), known under the common name “baylahuen”, are used as herbal teas in Chile and Argentina. In Chile, “baylahuen” comprises H. multifolius, H. taeda, H. baylahuen and H. rigidus. Little is known about the chemical identity of the infusion constituents in spite of widespread consumption. The aim of the present work was the characterization of phenolics occurring in the infusions and methanol extracts of “baylahuen” by HPLC-DAD-ESI-MS. A simple HPLC-DAD-ESI-MS method was developed for the fast identification and differentiation of Haplopappus spp. used as a tea source, based on the phenolics from the tea and methanol extracts. Some 27 phenolics were tentatively identified in the infusions and methanol extract, including 10 caffeoyl quinic and feruloyl quinic acid derivatives and 17 flavonoids. The HPLC patterns of the Haplopappus tea and methanol extract allow a clear differentiation at the species level. The occurrence of hydroxycinnamic acid derivatives and flavonoids can explain the reputed nutraceutical and health beneficial properties of this herbal tea.

Anthocyanins and antioxidant capacities of six Chilean berries by HPLC–HR-ESI-ToF-MS

The HPLC profiles of six fruits endemic of the VIII region of Chile were investigated using high resolution mass analysis (HR-ToF-ESI-MS). The anthocyanin fingerprints generated for the fruits were compared and the antioxidant capacities measured by the scavenging of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and correlated with the inhibition of lipid peroxidation in human erythrocytes (LP) and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Several anthocyanins were identified, including 3-O-glycosides derivatives of delphinidin, cyanidin, petunidin, peonidin and malvidin. Three phenolic acids (feruloyl-quinic acid, chlorogenic acid, and neochlorogenic acid) and five flavonols (hyperoside, isoquercitrin, quercetin, rutin, myricetin and isorhamnetin) were also identified. Calafate fruits showed the highest antioxidant activity. However, the highest LP activity was found for Chilean blueberries (>95%) followed by calafate fruits (91.27%) and luma (83.4%).

Antioxidant activities and phenolics profiling of different parts of Carica papaya by LCMS-MS

This article deals with the comparison of the antioxidant activity of aqueous extracts of various parts of Carica papaya L. The evaluation of total phenolic content and total flavonoid content revealed high antioxidant potential of the seeds and fruits. The free radical-scavenging potential of the aqueous extracts indicated the seeds to have better DPPH-scavenging activity than fruits. The results were augmented by the FRAP activity as well. The phenolics present in the extracts were separated and identified as 5-hydroxy feruloyl quinic acid, acetyl p-coumaryl quinic acid, quercetin-3-O-rhamnoside, syringic acid hexoside, 5-hydroxy caffeic quinic acid, peonidin-3-O-glucoside, sinapic acid-O-hexoside, cyaniding-3-O-glucose and methyl feruloyl glycoside by LCMS-MS technique.

In vitro enzymic hydrolysis of chlorogenic acids in coffee.

Coffee is rich in quinic acid esters of phenolic acids (chlorogenic acids) but also contains some free phenolic acids. A proportion of phenolic acids appear in the blood rapidly after coffee consumption due to absorption in the small intestine. We investigated in vitro whether this appearance could potentially be derived from free phenolic acids in instant coffee or from hydrolysis of chlorogenic acids by pancreatic or brush border enzymes. We quantified six free phenolic acids in instant coffees using HPLC-DAD-mass spectrometry. The highest was caffeic acid, but all were present at low levels compared to the chlorogenic acids. Roasting and decaffeination significantly reduced free phenolic acid content. We estimated, using pharmacokinetic modelling with previously published data, that the contribution of these compounds to small intestinal absorption is minimal. Hydrolysis of certain chlorogenic acids was observed with human-differentiated Caco-2 cell monolayers and with porcine pancreatin, which showed maximal rates on 3- and 5-O-caffeoylquinic acids, respectively. The amounts of certain free phenolic acids in coffee could only minimally account for small intestinal absorption based on modelling. The hydrolysis of caffeoylquinic, but not feruloylquinic acids, by enterocyte and pancreatic esterases is potentially a contributing mechanism to small intestinal absorption.

The necrotrophic effector protein SnTox3 re-programs metabolism and elicits a strong defence response in susceptible wheat leaves.

BackgroundThe fungus Stagonospora nodorum is a necrotrophic pathogen of wheat. It causes disease by secreting proteinaceous effectors which interact with proteins encoded by dominant susceptibility genes in the host. The outcome of these interactions results in necrosis, allowing the fungus to thrive on dead plant material. The mechanisms of these effectors though are poorly understood. In this study, we undertake a comprehensive transcriptomics, proteomic and metabolomic approach to understand how a susceptible wheat cultivar responds to exposure to the Stagonospora nodorum effector protein SnTox3.ResultsMicroarray and proteomic studies revealed that SnTox3 strongly induced responses consistent with those previously associated with classical host defence pathways including the expression of pathogenicity-related proteins and the induction of cell death. Collapse of the photosynthetic machinery was also apparent at the transcriptional and translational level. SnTox3-infiltrated wheat leaves also showed a strong induction of enzymes involved in primary metabolism consistent with increases in hexoses, amino acids and organic acids as determined by primary metabolite profiling. Methionine and homocysteine metabolism was strongly induced upon exposure to SnTox3. Pathogenicity in the presence of homocysteine was inhibited confirming that the compound has a role in plant defence. Consistent with the strong defence responses observed, secondary metabolite profiling revealed the induction of several compounds associated with plant defence, including the phenylpropanoids chlorogenic acid and feruloylquinic acid, and the cyanogenic glucoside dhurrin. Serotonin did not accumulate subsequent to SnTox3 infiltration.ConclusionsThese data support the theory that the SnTox3 effector protein elicits a host cell death response to facilitate the pathogen’s necrotrophic infection cycle. Our data also demonstrate that the mechanism of SnTox3 appears distinct from the previously characterised Stagonospora nodorum effector SnToxA. Collectively, this comprehensive analysis has advanced our understanding of necrotrophic effector biology and highlighted the complexity of effector-triggered susceptibility.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0215-5) contains supplementary material, which is available to authorized users.

A comprehensive characterisation of beer polyphenols by high resolution mass spectrometry (LC–ESI-LTQ-Orbitrap-MS)

Beer is the second most consumed alcoholic beverage in Europe and shown by the European Prospective Investigation into Cancer and Nutrition cohort study to be the main food contributor to hydroxybenzoic acid intake. About 70–80% of the total polyphenol content in beer comes from malt, and the remaining 30–20% from hops. In this work, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique has been used for an accurate identification of beer polyphenols. 47 phenolic compounds were identified using high mass accuracy and confirmed by MS2 experiments, including simple phenolic acids, hydroxycinnamoylquinics, flavanols, flavonols, flavones, alkylmethoxyphenols, alpha- and iso-alpha-acids, hydroxyphenylacetic acids and prenylflavonoids. As far as we know, 7 of these compounds have been recognised in beer for the first time: feruloylquinic acid, caffeic acid-O-hexoside, coumaric acid-O-hexoside, sinapic acid-O-hexoside, catechin-O-dihexoside, kaempferol-O-hexoside, and apigenin-C-hexoside-pentoside.

Anthocyanin characterization, total phenolic quantification and antioxidant features of some Chilean edible berry extracts.

The anthocyanin composition and HPLC fingerprints of six small berries endemic of the VIII region of Chile were investigated using high resolution mass analysis for the first time (HR-ToF-ESI-MS). The antioxidant features of the six endemic species were compared, including a variety of blueberries which is one of the most commercially significant berry crops in Chile. The anthocyanin fingerprints obtained for the fruits were compared and correlated with the antioxidant features measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Thirty one anthocyanins were identified, and the major ones were quantified by HPLC-DAD, mostly branched 3-O-glycosides of delphinidin, cyanidin, petunidin, peonidin and malvidin. Three phenolic acids (feruloylquinic acid, chlorogenic acid, and neochlorogenic acid) and five flavonols (hyperoside, isoquercitrin, quercetin, rutin, myricetin and isorhamnetin) were also identified. Calafate fruits showed the highest antioxidant activity (2.33 ± 0.21 μg/mL in the DPPH assay), followed by blueberry (3.32 ± 0.18 μg/mL), and arrayán (5.88 ± 0.21), respectively.

Resource assessment and economic potential of bilberries (Vaccinium myrtillus and Vaccinium uliginosum) on Osogovo Mtn., R. Macedonia

Bilberries in Macedonia represent significant natural resource that provides additional income for number of people. However, the systems for collection, licensing, control and monitoring are still not well developed in most of the Republic of Macedonia which puts pressure on natural habitats and wild species and leads to unsustainable use.The aim of this paper is to assess the economic potential based on sustainable usage of bilberries (Vaccinium myrtillus – European bilberry and Vaccinium uliginosum – Bog bilberry) on Osogovo Mtn., north-east Macedonia by intensive field assessment of annual production of fruits and leaves along with chemical characterization of the leaves and analysis of the importance of bilberries for local population.Field methods for assessment of surface of the heathlands and were based on remote sensing and ground truth data by using GIS; leaves and fruits production was estimated by standard transect square method; chemical characterization of the leaves was done by HPLC/DAD/ESI-MSn.The average production of dry leaves and fruits was 11.7gm−2 and 213.2gm−2, respectively.The total dry fruits biomass on Osogovo Mtn. in 2008 was estimated at 249.11t (218.82t in heathlands) from which 53% was European bilberry fruits. The total dry leaves biomass was estimated at 1459.4t (927.1t of European bilberry).The total content of all phenolic compounds in freeze-dried extract of V. myrtillus was 36.53mgg−1. Phenolic acids (caffeic acid and its esters with quinic acid and glucose, or other hydroxycinammic acids such as p-coumaric, p-coumaroylquinic or feruloylquinic acid and corresponding p-coumaroyl glucoside) represented 36% of total phenolic compounds in the European bilberry leaves extract, followed by flavonols (60%) and catechin (4%).Estimated economic income of sustainable use of fruits and leaves is 1.6 and 0.5milion€, respectively. This amount can support 340 people with average Macedonian annual gross salary.

ABTS radical scavenging capacity in green and roasted coffee extracts

The impact of two parameters (temperature and duration) on the radical scavenging capacity of individual compounds, and total extracts found in coffee was investigated. Phenolic coffee extracts of light (200 °C), medium (225 °C) and dark (235 °C) roasted coffees in a range of 0–30 min were analyzed by an on-line RP-HLPC-ABTS•+ decolourization assay. This study revealed a general decrease of radical scavenging capacity related to native phenolic compounds. Processing coffee beans leads to generation of up to 10 new radical scavengers. The roasting process influences not only color and taste in coffees, but also the radical scavenging capacity of coffee as well. Phenolic content in roasted coffee and green coffee is very different. Six compounds identified as caffeoylquinic acids and dicaffeoylquinic acids, endowed with radical scavenging capacity were found in green coffee, whereas depending on the roasting process, roasted coffees can present up to 16 different radical scavengers. The compounds formed during the roast are most likely chlorogenic acids derivatives, of which 4 could be clearly identified as two feruloylquinic acids and two caffeoylquinides. In longer roasting durations, these molecules are subjected to auto-degradation, thus total radical scavenging capacity in coffee decline along with roasting (duration and temperature).

Development and Optimization of an UPLC-QTOF-MS/MS Method Based on an In-Source Collision Induced Dissociation Approach for Comprehensive Discrimination of Chlorogenic Acids Isomers from Momordica Plant Species.

Chlorogenic acids (CGA) have been profiled in the leaves of Momordica balsamina, Momordica charantia, and Momordica foetida. All three species were found to contain the trans and cis isomers of 4-acyl para-coumaroylquinic acid (pCoQA), caffeoylquinic acid (CQA), and feruloylquinic acid (FQA). To the best of our knowledge, this is the first report of pCoQA and FQA and their cis isomers in these Momordica species. These profiles were obtained by a newly developed UPLC-qTOF-MS method based on the in-source collision induced dissociation (ISCID) method optimized to mimic the MS2 and MS3 fragmentation of an ion trap-based MS. The presence of the cis isomers is believed to be due to high UV exposure of these plants. Furthermore, the absence of the 3-acyl and 5-acyl CGA molecules points to a metabolic mark that is unusual and represents a very interesting biochemical phenotype of these species. Our optimized ISCID method was also shown to be able to distinguish between the geometrical isomers of all three forms of CGA, a phenomenon previously deemed impossible with other common mass spectrometry systems used for CGA analyses.

Analysis of phenolic acids of Jerusalem artichoke (Helianthus tuberosus L.) responding to salt-stress by liquid chromatography/tandem mass spectrometry.

Plant phenolics can have applications in pharmaceutical and other industries. To identify and quantify the phenolic compounds in Helianthus tuberosus leaves, qualitative analysis was performed by a reversed phase high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) and quantitative analysis by HPLC. Ten chlorogenic acids (CGAs) were identified (3-o-caffeoylquinic acid, two isomers of caffeoylquinic acid, caffeic acid, p-coumaroyl-quinic acid, feruloylquinic acid, 3,4-dicaffeoyquinic acid, 3,5-dicaffeoylquinic acid, 1,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid) by comparing their retention times, UV-Vis absorption spectra, and MS/MS spectra with standards. In addition, four other phenolic compounds, including caffeoyl glucopyranose, isorhamnetin glucoside, kaempferol glucuronide, and kaempferol-3-o-glucoside, were tentatively identified in Helianthus tuberosus leaves for the first time. The 3-o-caffeoylquinic acid (7.752 mg/g DW), 4,5-dicaffeoylquinic acid (5.633 mg/g DW), and 3,5-dicaffeoylquinic acid (4.900 mg/g DW) were the major phenolic compounds in leaves of Helianthus tuberosus cultivar NanYu in maturity. The variations in phenolic concentrations and proportions in Helianthus tuberosus leaves were influenced by genotype and plant growth stage. Cultivar NanYu had the highest concentration of phenolic compounds, in particular 3-o-caffeoylquinic acid and 4,5-dicaffeoylquinic acid compared with the other genotypes (wild accession and QingYu). Considering various growth stages, the concentration of total phenolics in cultivar NanYu was higher at flowering stage (5.270 mg/g DW) than at budding and tuber swelling stages. Cultivar NanYu of Helianthus tuberosus is a potential source of natural phenolics that may play an important role in the development of pharmaceuticals.

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.

On‐line process monitoring of coffee roasting by resonant laser ionisation time‐of‐flight mass spectrometry: bridging the gap from industrial batch roasting to flavour formation inside an individual coffee bean

Resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOFMS) enables the fast and sensitive on-line monitoring of volatile organic compounds (VOC) formed during coffee roasting. On the one hand, REMPI-TOFMS was applied to monitor roasting gases of an industrial roaster (1500 kg/h capacity), with the aim of determining the roast degree in real-time from the transient chemical signature of VOCs. On the other hand, a previously developed μ-probe sampling device was used to analyse roasting gases from individual coffee beans. The aim was to explore fundamental processes at the individual bean level and link these to phenomena at the batch level. The pioneering single-bean experiments were conducted in two configurations: (1) VOCs formed inside a bean were sampled in situ, i.e. via a drilled μ-hole, from the interior, using a μ-probe (inside). (2) VOCs were sampled on-line in close vicinity of a single coffee bean's surface (outside). The focus was on VOCs originating from hydrolysis and pyrolytic degradation of chlorogenic acids, like feruloyl quinic acid and caffeoyl quinic acid. The single bean experiments revealed interesting phenomena. First, differences in time-intensity profiles between inside versus outside (time shift of maximum) were observed and tentatively linked to the permeability of the bean's cell walls material. Second, sharp bursts of some VOCs were observed, while others did exhibit smooth release curves. It is believed that these reflect a direct observation of bean popping during roasting. Finally, discrimination between Coffea arabica and Coffea canephora was demonstrated based on high-mass volatile markers, exclusively present in spectra of Coffea arabica.

Phenolic composition, caffeine content and antioxidant capacity of coffee silverskin

Coffea arabica silverskin (CSS), the inner fruit layer surrounding coffee beans, was analyzed for its (poly)phenolic and caffeine content by means of liquid chromatography–tandem mass spectrometry and evaluated for its antioxidant properties by means of the Folin–Ciocalteu and FRAP methods. The most abundant quantified phenolics were caffeoylquinic acids, with the 5- and 3-isomers being the most relevant (199mg/100g and 148mg/100g, respectively). The three caffeoylquinic acid isomers reached a total concentration of 432mg/100g, corresponding to 74% of the total chlorogenic acids detected in CSS. The level of the three feruloylquinic acids detected was 143mg/100g, corresponding to 23%, and the two identified coumaroylquinic acids plus the two caffeoylquinic acid lactones were only marginally contributing to the final figure (only 3% of total hydroxycinnamates). No unconjugated phenolic acid was detected. Caffeine content in CSS was equal to 10mg/g of product, 3.5 times lower than most coffee brews. The total antioxidant capacity (TAC) of CSS was 139mmol Fe2+/kg, a value similar to those of valuable sources of food antioxidants like dark chocolate, herbs and spices. Besides its potential as a food supplement, CSS may represent an innovative functional ingredient exploitable to increase the TAC of a wide range of food products.

Composition, antifungal and antioxidant properties of Hyssopus officinalis L. subsp. pilifer (Pant.) Murb. essential oil and deodorized extracts

The aim of the study was to investigate the chemical composition of Hyssopus officinalis L. subsp. pilifer (Pant.) Murb. essential oil (EO) and deodorized extracts (DE) and to evaluate their potential antifungal and antioxidant activities. EO was analyzed by GC–FID and GC–MS. Among the 30 compounds identified in the oil, the main were 1.8-cineole (36.43%), β-pinene (19.55%), isopinocamphone (15.32%) and trans-pinocamphone (6.39%). Deodorized aqueous extract (DAE) was analyzed by LC-DAD/ESI-TOF MS. The most significant phenolic acids detected in DAE were syringic, caffeoylqunic acids, feruloylquinic and rosmarinic acid. Aspergillus niger, A. ochraceus, A. versicolor, A. fumigatus, Cladosporium cladosporioides, C. fulvum, Penicillium funiculosum, P. ochrochloron, Trichoderma viride and Candida albicans yeast were used for antifungal assay. Minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of the tested EO and DEs were recorded by the microdilution method. The antioxidant potential of the extracts was evaluated by means of the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging method. The deodorized aqueous extract (DAE) possessed the highest scavenging activity (EC50=0.54mg/ml) followed by the deodorized methanol extract (DME) (EC50=0.82mg/ml) and deodorized ethyl acetate extract (DEE) (EC50=2.97mg/ml). EO possessed the lowest activities compared to other extracts and control substances. Total phenolic content of DEs was determined by Folin–Ciocalteau (FC) assay and gallic acid was used as the standard. DAE of H. officinalis subsp. pilifer exhibited the highest phenolic content 96.47 GAE.

The effect of processing on chlorogenic acid content of commercially available coffee

Chlorogenic acids (CGA) are a class of polyphenols noted for their health benefits. These compounds were identified and quantified, using LC–MS and HPLC, in commercially available coffees which varied in processing conditions. Analysis of ground and instant coffees indicated the presence of caffeoylquinic acids (CQA), feruloylquinic acids (FQA) and dicaffeoylquinic acids (diCQA) in all 18 samples tested. 5-CQA was present at the highest levels, between 25 and 30% of total CGA; subsequent relative quantities were: 4-CQA>3-CQA>5-FQA>4-FQA>diCQA (sum of 3,4, 3,5 and 4,5-diCQA). CGA content varied greatly (27.33–121.25mg/200ml coffee brew), driven primarily by the degree of coffee bean roasting (a high amount of roasting had a detrimental effect on CGA content). These results highlight the broad range of CGA quantity in commercial coffee and demonstrate that coffee choice is important in delivering optimum CGA intake to consumers.

Acylated sucroses and acylated quinic acids analogs from the flower buds of Prunus mume and their inhibitory effect on melanogenesis

The methanolic extract from the flower buds of Prunus mume, cultivated in Zhejiang Province, China, showed an inhibitory effect on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. From the methanolic extract, five acylated sucroses, mumeoses A-E, and three acylated quinic acid analogs, 5-O-(E)-p-coumaroylquinic acid ethyl ester, and mumeic acid-A and its methyl ester, were isolated together with 13 known compounds. The chemical structures of the compounds were elucidated on the basis of chemical and physicochemical evidence. Inhibitory effects of the isolated compounds on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells were also investigated. Acylated quinic acid analogs substantially inhibited melanogenesis. In particular, 5-O-(E)-feruloylquinic acid methyl ester exhibited a potent inhibitory effect [inhibition (%): 21.5±1.0 (P<0.01) at 0.1 μM]. Moreover, its biological effect was much stronger than that of the reference compound, arbutin [inhibition (%): 10.6±0.6 (P<0.01) at 10 μM]. Interestingly, the obtained acylated quinic acid analogs displaying melanogenesis inhibitory activity showed no cytotoxicity [cell viability >97% at 10 μM]. It is concluded that acylated quinic acid analogs are promising therapeutic agents for the treatment of skin disorders.