Caffeoylferuloylquinic Acids Research Articles

Bioprospecting of Artemisia genus: from artemisinin to other potentially bioactive compounds

Species from genus Artemisia are widely distributed throughout temperate regions of the northern hemisphere and many cultures have a long-standing traditional use of these plants as herbal remedies, liquors, cosmetics, spices, etc. Nowadays, the discovery of new plant-derived products to be used as food supplements or drugs has been pushed by the exploitation of bioprospection approaches. Often driven by the knowledge derived from the ethnobotanical use of plants, bioprospection explores the existing biodiversity through integration of modern omics techniques with targeted bioactivity assays. In this work we set up a bioprospection plan to investigate the phytochemical diversity and the potential bioactivity of five Artemisia species with recognized ethnobotanical tradition (A. absinthium, A. alba, A. annua, A. verlotiorum and A. vulgaris), growing wild in the natural areas of the Verona province. We characterized the specialized metabolomes of the species (including sesquiterpenoids from the artemisinin biosynthesis pathway) through an LC–MS based untargeted approach and, in order to identify potential bioactive metabolites, we correlated their composition with the in vitro antioxidant activity. We propose as potential bioactive compounds several isomers of caffeoyl and feruloyl quinic acid esters (e.g. dicaffeoylquinic acids, feruloylquinic acids and caffeoylferuloylquinic acids), which strongly characterize the most antioxidant species A. verlotiorum and A. annua. Morevoer, in this study we report for the first time the occurrence of sesquiterpenoids from the artemisinin biosynthesis pathway in the species A. alba.

Lipid oxidation and changes in the phenolic profile of watercress (Nasturtium officinale L.) leaves during frying

Watercress leaves were fried in sunflower oil and analysed for lipid oxidation and phenolic compounds by high-performance liquid chromatography with diode array detection (HPLC–DAD). Results revealed that total phenolic contents and radical scavenging activity decreased significantly at the initial stages and were stable in frying oil, indicating stability of frying oil. A significant increase occurred in chlorophylls of watercress leaves and frying oil. HPLC chromatograms showed a total of 12 phenolic compounds containing caftaric acid (17.3–31.8 µg/g), sinapic acid derivative (11.2–14.4 µg/g), 4-O-caffeoylquinic acid (9.98–12.8 µg/g), 4-O-feruloyl quinic acid (8.47–13.4 µg/g), caffeoyl feruloyl quinic acid (7.31–11.7 µg/g) and 5-O-caffeoylquinic acid (3.73–6.51 µg/g) as major compounds. A significant increase in the caffeic acid, caffeoyl hexose, chlorogenic acid, caftaric acid, coumaric acid derivatives and 3, 4-di-O-caffeoylquinic acid was observed, while a decrease occurred in Sinapic acid derivative, 5-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 4-O-feruloyl quinic acid and caffeoyl feruloyl quinic acid. Frying of watercress leaves increase the bioavailability of medicinally important phenolic compounds and also help to stabilise the frying oil.

Identification and chromatographic determination of bioactive components in the instant coffee samples

This work is devoted to the identification of chlorogenic acids and their lactones as well as to the determination of the main isomers of these acids and caffeine in the instant coffee samples by HPLC-UV-MS. The features of HPLC determination of bioactive components (alkaloids and phenolic compounds) in coffee are discussed. The conditions for chromatographic separation of the main phenolic compounds - isomers of chlorogenic acids (CGA) and their derivatives, as well as for the caffeine in instant coffee, are selected. As a result of these studies the major components corresponding to the main isomers of caffeoylquinic acids (CQA) - 5-caffeoylquinic acid (5-CQA), 3-caffeoylquinic acid (3-CQA) and caffeine were identified. Using the literature data and the results of HPLC-UV-MS analysis the isomers of caffeoylquinic acids, feruloylquinic acids (FQA) and dicaffeoylquinic acids (diCQA) and some of their lactones were identified in the test samples of instant coffee. The components with m/z values of their deprotonated ions, which correspond to the coumaroylquinic, caffeoylferuloylquinic acids (CFQA) and some conjugates of cinnamic acid and tryptophan derivatives, were found. The content of 5-CQA, 3-CQA and caffeine in thirteen analyzed samples of instant coffee was determined and varied in the ranges of 3.4-11.6, 5.3-23.0 and 23.5-42.4 mg/g respectively. It was shown that the content of CGA in instant coffee can be an effective indicator of the quality of the product. Keywords : HPLC-UV-MS, isomers of chlorogenic acids, lactones of chlorogenic acids, caffeine, instant coffee DOI: http://dx.doi.org/10.15826/analitika.2017.21.3.008 E.A. Tishchenko, T.G. Tsiupko, V.V. Milevskaia, А .Z. Temerdashev Kuban State University, Stavropolskaia ul., 149, Krasnodar, 350040, Russia Federation

Exhaustive Qualitative LC-DAD-MSn Analysis of Arabica Green Coffee Beans: Cinnamoyl-glycosides and Cinnamoylshikimic Acids as New Polyphenols in Green Coffee.

Coffee is one of the most consumed beverages in the world, due to its unique aroma and stimulant properties. Although its health effects are controversial, moderate intake seems to be beneficial. The present work deals with the characterization and quantification of polyphenols and methylxanthines in four Arabica green coffee beans from different geographical origins. The antioxidant activity was also evaluated. Forty-three polyphenols (cinnamic acid, cinnamoyl-amide, 5 cinammoyl-glycosides, and 36 cinnamate esters) were identified using LC-MSn. Among these, cinnamate esters of six different chemical groups (including two dimethoxycinnamoylquinic acid isomers, three caffeoyl-feruloylquinic acid isomers, caffeoyl-sinapoylquinic acid, p-coumaroyl-feruloylquinic acid, two caffeoylshikimic acid isomers, and trimethoxycinnamoylshikimic acid) in addition to five isomers of cinnamoyl-glycosides called caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosic acid (CDOA) are described for the first time in Arabica green coffee beans. Moreover, 38 polyphenols (6-7% w/w) and 2 methylxanthines (1.3% w/w) were quantified by HPLC-DAD. Caffeoylquinic was the most abundant group of compounds (up to 85.5%) followed by dicaffeoylquinic and feruloylquinic acids (up to 8 and 7%, respectively) and the newly identified cinnamoyl-glycosides (CDOA) (up to 2.5%). Caffeine was the main methylxanthine (99.8%), with minimal amounts of theobromine (0.2%). African coffees (from Kenya and Ethiopia) showed higher polyphenolic content than American beans (from Brazil and Colombia), whereas methylxanthine contents varied randomly. Both phenols and methylxanthines contributed to the antioxidant capacity associated with green coffee, with a higher contribution of polyphenols. We conclude that green coffee represents an important source of polyphenols and methylxanthines, with high antioxidant capacity.

In vivo diabetic wound healing effect and HPLC–DAD–ESI–MS/MS profiling of the methanol extracts of eight Aloe species

Genus Aloe, Xanthorrhoeaceae, is well distributed all over Egypt, and many species have been used as medicinal plants; mainly reported to prevent cardiovascular diseases, cancer and diabetes. This study attempts to analyze the secondary metabolites in the methanol extract of the leaves of eight Aloe species; A. vera (L.) Burm. f., A. arborescens Mill., A. eru A. Berger, A. grandidentata Salm-Dyck, A. perfoliata L., A. brevifolia Mill., A. saponaria Haw. and A. ferox Mill. growing in Egypt. For this aim HPLC–DAD–MS/MS in negative ion mode was used. Although belonging to the same genus, the composition of each species presented different particularities. Seventy one compounds were identified in the investigated Aloe species, of which cis-p-coumaric acid derivaties, 3,4-O-(E) caffeoylferuloylquinic acid and caffeoyl quinic acid hexoside were the most common phenolic acids identified. Aloeresin E and isoaloeresin D, 2′-O-feruloylaloesin were the common anthraquinones identified. Lucenin II, vicenin II, and orientin were the common identified flavonoids in the investigated Aloe species. 6′-Malonylnataloin, aloe-emodin-8-O-glucoside, flavone-6,8-di-C-glucosides could be considered as chemotaxonomic markers for the investigated Aloe species. The eight Aloe species had significant anti-inflammatory activity, in addition to the significant acceleration of diabetic wound healing in rats following topical application of the methanol extracts of their leaves. This is the first simultaneous characterization and qualitative determination of multiple phenolic compounds in Aloe species from locally grown cultivars in Egypt using HPLC–DAD–MS/MS, which can be applied to standardize the quality of different Aloe species and the future design of nutraceuticals and cosmetic preparations.

Typical ultraviolet spectra in combination with diagnostic mass fragmentation analysis for the rapid and comprehensive profiling of chlorogenic acids in the buds of Lonicera macranthoides.

A major challenge of profiling chlorogenic acids (CGA) in natural products is to effectively detect unknown or minor isomeric compounds. Here, we developed an effective strategy, typical ultraviolet (UV) spectra in combination with diagnostic mass fragmentation analysis based on HPLC-DAD-QTOF-MS/MS, to comprehensively profile CGA in the buds of Lonicera macranthoides. First, three CGA UV patterns were obtained by UV spectra screening. Second, 13 types of CGA classified by molecular weights were found by thorough analysis of CGA peaks using high-resolution MS. Third, selected ion monitoring (SIM) was carried out for each type of CGA to avoid overlooking of minor ones. Fourth, MS/MS spectra of each CGA were investigated. Then 70 CGA were identified by matching their UV spectra, accurate mass signals and fragmentation patterns with standards or previously reported compounds, including six caffeoylquinic acids (CQA), six diCQA, one triCQA, three caffeoylshikimic acids (CSA), six diCSA, one triCSA, three p-coumaroylquinic acids (pCoQA), four p-coumaroylcaffeoylquinic acids (pCoCQA), four feruloylquinic acids (FQA), five methyl caffeoylquinates (MCQ), three ethyl caffeoylquinates (ECQ), three dimethoxycinnamoylquinic acids (DQA), six caffeoylferuloylquinic acids (CFQA), six methyl dicaffeoylquinates (MdiCQ), four FQA glycosides (FQAG), six MCQ glycosides (MCQG), and three ethyl dicaffeoylquinates (EdiCQ). Forty-five of them were discovered from Lonicera species for the first time, and it is noted that CGA profiles were investigated for the first time in L. macranthoides. Results indicated that the developed method was a useful approach to explore unknown and minor isomeric compounds from complex natural products.

TLC-DPPH•activity-guided separation and LC-DAD-MS identification of antioxidant compounds fromMutellina purpureaL. herb

Many phytochemical investigations have been focused recently on the antioxidant activity of herbal extracts which can be used in phytotherapy. The previous study revealed antioxidative properties of Mutellina purpurea extract, but the constituents responsible for this action were not described yet. The aim of this study was activityguided separation and identification of antioxidant compounds from M. purpurea herb. Thin-layer chromatography-2,2-diphenyl-1-picrylhydrazyl (TLC-DPPH•) assay was used to detect compounds of interest; liquid chromatography-diode array detection-mass spectrometry (LC-DAD-MS) analysis allowed to identify antioxidants. The active fractions analyzed with LC-DAD-MS contained as a main compound chlorogenic acid accompanied with p-coumaric acid, ferulic acid, three dicaffeoylquinic acids, and caffeoylferuloylquinic acid. The fast TLC-DPPH• assay with LC-DAD-MS identification enabled the accurate identification of antioxidants in M. purpurea herb, which was done for the first time.

Identification and quantification of bioactive compounds in coffee brews by HPLC–DAD–MSn

Coffee is a beverage widely consumed worldwide because of its organoleptic characteristics and stimulating and beneficial health effects. This paper presents the identification and quantification of chlorogenic acids and derivatives, trigonelline, nicotinic acid, 5-hydroxymethylfurfural, theobromine, theophylline, and caffeine in brews of 10 roasted ground coffee and 4 soluble coffee determined by HPLC–DAD–MSn. Among the chlorogenic acids and derivatives, 17 chlorogenic acids, 5 chlorogenic acid lactones, 2 cinnamoyl-amino acid conjugates, and 2 free cinnamic acids were identified. This is the first study that reports the presence of caffeoylferuloylquinic acid isomers, and cinnamoyl-amino acid conjugates in soluble coffee brews. Regular roasted ground coffee brews showed higher contents of chlorogenic acids (4162mg/100g), chlorogenic acid lactones (779mg/100g), p-coumaric acid (2.4mg/100g), trigonelline (2044mg/100g), nicotinic acid (100.4mg/100g), caffeine (4565mg/100g), and theobromine (12.5mg/100g) than regular soluble coffee brews. Decaffeinated coffee brews presented higher levels of chlorogenic acids, chlorogenic acid lactones, caffeic acid, and trigonelline when compared to the regular ones. Despite the differences in the levels of these compounds, brews of roasted ground coffee and soluble coffee, both regular and decaffeinated, represent an important source of bioactive compounds for habitual coffee consumers.

Polyphenolic and Hydroxycinnamate Contents of Whole Coffee Fruits from China, India, and Mexico

Air-dried whole coffee fruits, beans, and husks from China, India, and Mexico were analyzed for their chlorogenic acids (CGA), caffeine, and polyphenolic content. Analysis was by HPLC and Orbitrap exact mass spectrometry. Total phenol, total flavonol, and antioxidant capacity were measured. The hydroxycinnamate profile consisted of caffeoylquinic acids, feruloyquinic acids, dicaffeoylquinic acids, and caffeoyl-feruloylquinic acids. A range of flavan-3-ols as well as flavonol conjugates were detected. The CGA content was similar for both Mexican and Indian coffee fruits but was much lower in the samples from China. Highest levels of flavan-3-ols were found in the Indian samples, whereas the Mexican samples contained the highest flavonols. Amounts of CGAs in the beans were similar to those in the whole fruits, but flavan-3-ols and flavonols were not detected. The husks contained the same range of polyphenols as those in the whole fruits. The highest levels of caffeine were found in the Robusta samples.

Diagnostic fragment-ion-based and extension strategy coupled to DFIs intensity analysis for identification of chlorogenic acids isomers in Flos Lonicerae Japonicae by HPLC-ESI-MSn

A method of modified diagnostic fragment-ion-based extension strategy (DFIBES) coupled to DFIs (diagnostic fragmentation ions) intensity analysis was successfully established to simultaneously screen and identify the chlorogenic acids (CGAs) in Flos Lonicerae Japonicae (FLJ) by HPLC-ESI-MSn. DFIs, such as m/z 191 [quinic acid-H]−, m/z 179 [caffeic acid-H]− and m/z 173 [quinic acid–H–H2O]− were determined or proposed from the fragmentation patterns analysis of corresponding reference substances for every chemical family of CGAs. A “structure extension” method was then proposed based on the well-demonstrated fragmentation patterns and was successively applied into the rapid screening of CGAs in FLJ. Considering that substitution isomerism is a common phenomenon, a full ESI-MSn fragmentation analysis according to the intensity of DFIs has been performed to identify the CGA isomers. Based on the DFIs and intensity analysis, 41 peaks attributed to CGAs including 4 caffeoylquinic acids (CQA), 7 CQA glycosides, 6 dicaffeoylquinic acids (DiCQA), 10 DiCQA glycosides, 1 tricaffeoylquinic acids (TriCQA), 4p-coumaroylquinic acids (pCoQA), 3 feruloylquinic acids (FQA) and 6 caffeoylferuloylquinic acids (CFQA) were identified preliminarily in a 65-min chromatographic run. It was the first time to systematically report the presence of CGAs in FLJ, especially for CQA glycosides, DiCQA glycosides, TriCQA, pCoQA and CFQA. All the results indicated that the method of developed DFIBES coupled to DFIs analysis was feasible, reliable and universal for screening and identifying the constituents with the same carbon skeletons especially the isomeric compounds from the complex extract of TCMs.

Characterization and Quantification of Hydroxycinnamate Derivatives in Stevia rebaudiana Leaves by LC-MSn

Stevia rebaudiana leaves are used as a zero-calorie natural sweetener in a variety of food products in Asian countries, especially in Japan. In this study, the hydroxycinnamate derivatives of S. rebaudiana have been investigated qualitatively and quantitatively by LC-MSn. Twenty-four hydroxycinnamic acid derivatives of quinic and shikimic acid were detected, and 19 of them were successfully characterized to regioisomeric levels; 23 are reported for the first time from this source. These comprise three monocaffeoylquinic acids (Mr 354), seven dicaffeoylquinic acids (Mr 516), one p-coumaroylquinic acid (Mr 338), one feruloylquinic acid (Mr 368), two caffeoyl-feruloylquinic acids (Mr 530), three caffeoylshikimic acids (Mr 336), and two tricaffeoylquinic acids (Mr 678). Cis isomers of di- and tricaffeoylquinic acids were observed as well. Three tricaffeoylquinic acids identified in stevia leaves are reported for the first time in nature. These phenolic compounds identified in stevia might affect the organoleptic properties and add additional beneficial health effects to stevia-based products.

Determination of the hydroxycinnamate profile of 12 members of the Asteraceae family

The hydroxycinnamates of the leaves of 12 plants of the Astreraceae family, Achillea millefolium, Arnica montana, Artemesia dracunculus, Cichorium intybus, Cnicus benedictus, Cynara scolymus, Echinops humilis, Inula helenium, Lactuca sativa, Petasites hybridus, Solidago virgaurea, and Tanacetum parthenium were investigated qualitatively by LC–MS n . Thirty-nine chlorogenic acids were detected and all characterized to regioisomeric level on the basis of their fragmentation pattern in the tandem MS spectra, most of them for the first time from these sources with two of them previously not reported in nature. Both chlorogenic acids based on trans and cis-cinnamic acid substituents were identified. Assignment to the level of individual regioisomers was possible for seven caffeoylquinic acids ( 1–7), 11 dicaffeoylquinic acids ( 17–27), six feruloylquinic acids ( 9–14), two p-coumaroylquinic acids ( 15–16), two caffeoyl–feruloylquinic acids ( 28 and 29), four caffeoyl- p-coumaroylquinic acids ( 30– 33), three dicaffeoyl–succinoylquinic acids ( 34– 36), two dicaffeoyl–methoxyoxaloylquinic acids ( 37 and 38), and one tricaffeoylquinic acid ( 39). Furthermore, one caffeoylshikimic acid ( 40), one caffeoyltartaric acid ( 41), three dicaffeoyltartaric acids ( 42– 44), and three caffeoyl–feruloyltartaric acids ( 45– 47) were detected and shown to possess characteristic tandem MS spectra and were tentatively assigned on the basis of their retention time and previously developed hierarchical keys.

The Antioxidant and Chlorogenic Acid Profiles of Whole Coffee Fruits Are Influenced by the Extraction Procedures

Commercial whole coffee fruit extracts and powder samples were analyzed for chlorogenic acids (CGA), caffeine and antioxidant activities. CGA and caffeine were characterized by LC-MS(n) and HPLC accordingly, and quantified by UV absorbance. ORAC, HORAC, NORAC, SORAC and SOAC (antioxidant capacities) were assessed. Three caffeoylquinic acids, three feruloylquinic acids, three dicaffeoylquinic acids, one p-coumaroylquinic acid, two caffeoylferuloylquinic acids and three putative chlorogenic lactones were quantified, along with a methyl ester of 5-caffeoylquinic acid (detected in one sample, the first such report in any coffee material). Multistep whole coffee fruit extracts displayed higher CGA content than single-step extracts, freeze-dried, or air-dried whole raw fruits. Caffeine in multistep extracts was lower than in the single-step extracts and powders. Antioxidant activity in whole coffee fruit extracts was up to 25-fold higher than in powders dependent upon the radical. Total antioxidant activity of samples displayed strong correlation to CGA content.

Profiling and Characterization by LC-MSn of the Chlorogenic Acids and Hydroxycinnamoylshikimate Esters in Maté (Ilex paraguariensis)

The chlorogenic acids of mate (Ilex paraguariensis) have been investigated qualitatively by LC-MS(n). Forty-two chlorogenic acids were detected and all characterized to regioisomeric level on the basis of their fragmentation pattern in tandem MS spectra, 24 of them for the first time from this source. Both chlorogenic acids based on trans- and cis-cinnamic acid substituents were identified. Assignment to the level of individual regioisomers was possible for eight caffeoylquinic acids (1-8), five dicaffeoylquinic acids (20-24), six feruloylquinic acids (9-14), two diferuloyl quinic acids (25 and 26), five p-coumaroylquinic acids (15-19), four caffeoyl-p-coumaroylquinic acids (34-37), seven caffeoyl-feruloylquinic acids (27-33), three caffeoyl-sinapoylquinic acids (38-40), one tricaffeoylquinic acid (41), and one dicaffeoyl-feruloylquinic acid (42). Furthermore, four caffeoylshikimates (43-46), three dicaffeoylshikimates (47-49), one tricaffeoylshikimate (51), and one feruloylshikimate (50) have been detected and shown to possess characteristic tandem MS spectra and were assigned by comparison to reference standards.

Analysis of Phenolic Compounds in Ugandan Sweet Potato Varieties (NSP, SPK AND TZ)

Sweet potato varieties: Nsp, Tz and Spk obtained from Uganda were used in this study. Several phenolic compounds were identified on the basis of their mass spectra in full scan mode and the pattern of their fragmentation. The major compounds found were caffeoylquinic acid, dicaffeoylquinic acid, coumaroylquinic acid, feruloylquinic acid and caffeoylferuloylquinic acids. This is the first time that caffeoylferuloylquinic isomers have been identified in sweet potato samples.

Profiling the chlorogenic acids of sweet potato ( Ipomoea batatas) from China

The leaves, stem and root of sweet potato cultivated in China have been analysed qualitatively for chlorogenic acids by structure-diagnostic LC–MS 3. Chlorogenic acids were not detected in the root. Caffeoylquinic acids were quantitatively the major subgroup of chlorogenic acids detected in the stem and the only subgroup detected in the leaves. This subgroup was dominated by 5-caffeoylquinic acid. The stem also contained three feruloylquinic acids, 3,5- and 4,5-dicaffeoylquinic acid, and small amounts of at least four caffeoyl-feruloylquinic acids. This is the first report of feruloylquinic and caffeoyl-feruloylquinic acids from sweet potato. Two chemically unrelated and coeluting substances with the same molecular mass ( M r = 530) extracted from the Chinese sweet potato interfered with the characterisation of the caffeoyl-feruloylquinic acids. At least five caffeoyl-feruloylquinic acids were detected in the peel of sweet potato cultivated in Tanzania that lacked these interfering substances.

Profiling the chlorogenic acids of aster by HPLC–MSn

Using HPLC-MS(n), 33 chlorogenic acids were identified in an aqueous-alcoholic extract of Aster ageratoides Turcz. flower buds. These were three isomers each of p-coumaroylquinic acid, caffeoylquinic acid, feruloylquinic acid, dicaffeoylquinic acid and diferuloylquinic acid, and six isomers each of p-coumaroyl-caffeoylquinic acid, p-coumaroyl-feruloylquinic acid and caffeoyl-feruloylquinic acid. Only the caffeoylquinic acids and dicaffeoylquinic acids have been reported previously in Asteraceae. Three of the six p-coumaroyl-feruloylquinic acids (3-feruloyl-4-p-coumaroylquinic acid, '3-feruloyl-5-p-coumaroylquinic acid and 4-feruloyl-5-p-coumaroylquinic acid) have not been observed previously in nature. Cis-5-p-coumaroylquinic acid was identified at a concentration ca 25% that of the more common trans isomer. The feruloylquinic acids and diferuloylquinic acids dominated the mono- and di-acyl chlorogenic acid fractions, respectively, making this plant material a useful source of these commercially non-available substances. These 33 chlorogenic acids were not detected in the leaves or stem of A. ageratoides Turcz., or in the flower buds of A. ageratoides Turcz. var. Gerla or A. kalimeris indica (L) Sch. Bip. Only the feruloylquinic acids were detected in the root of A. ageratoides Turcz. It was not possible to detect any 1-acyl chlorogenic acids, any chlorogenic acids with a succinic acid substituent, or any chlorogenic acids based on muco-quinic acid.

Hierarchical scheme for LC-MSn identification of chlorogenic acids.

The fragmentation behavior of 18 chlorogenic acids that are not substituted at position 1 has been investigated using LC-MS(4) applied to a methanolic coffee bean extract and commercial cider (hard cider). Using LC-MS(3), it is possible to discriminate between each of the three isomers of p-coumaroylquinic acid, caffeoylquinic acid, feruloylquinic acid, and dicaffeoylquinic acid, and a hierarchical key has been prepared to facilitate this process when standards are not available. MS(4) fragmentations further support these assignments, but were not essential in reaching them. The distinctive behavior of 4-acyl and 3-acyl chlorogenic acids compared with the 5-acyl chlorogenic acids is a key factor permitting these assignments. The fragmentation patterns are dependent upon the particular stereochemical relationships between the individual substituents on the quinic acid moiety. Fragmentation is facilitated by 1,2-acyl participation and proceeds through quinic acid conformers in which the relevant substituents transiently adopt a 1,3-syn-diaxial relationship. Selected ion monitoring at m/z 529 clearly indicated the presence in coffee of six caffeoylferuloylquinic acid isomers, whereas previously only two or three had been demonstrated. The hierarchical key permitted specific structures to be assigned to each of the six isomers. These assignments are internally consistent and consistent with the limited data previously available.

Distinction between Arabica and Robusta Coffee Beans by Hydroxycinnamic Acid Derivatives, Especially by p-Coumaroyltryptophan.

Eleven chlorogenic acids, caffeoyltryptophan (CaT), and p-coumaroyltryptophan (CoT) in coffee beans (Coffea canephora var. robusta (Robusta) and C. arabica (Arabica)) and instant coffees on the market were analyzed by HPLC. Robusta beans contained more caffeoylferuloylquinic acids and CaT than Arabica beans. CoT was detected only in Robusta beans. The more intensely the coffee beans were roasted, the more all the chlorogenic acids decreased. CoT decreased the most slowly among phenols during roasting. Only instant coffees made of Robusta beans contained CoT. CoT becomes an indicator of Robusta beans.

Phenols and caffeine in wet-processed coffee beans and coffee pulp

The contents of low molecular mass phenols and caffeine have been analysed in five samples of beans and the associated pulp, derived from two species of coffee and two associated hybrids. The composition of the coffee beans was consistent with previous reports. The pulp contained smaller quantities of the same caffeoylquinic acids, feruloylquinic acids and dicaffeolyquinic acids as the beans, but caffeoylferuloylquinic acids were not found even in the pulp from a robusta coffee. Pulp from a robusta coffee had a lower caffeine content than the pulp from two arabica cultivars, the reverse of the situation existing in the beans. A significant component in all pulp samples was isolated and identified as protocatechuic acid.