Quinic Acid Esters Research Articles

The hydrates of chlorogenic acid in its aqueous solution and in stored food products

Chlorogenic acids (CQAs), a large family of naturally occurring esters of quinic acid with one, two or even three cinnamic acids moieties and/or moieties of cinnamic acids derivatives, supplied to human organisms mainly with coffee, tea, fruit and vegetables, have been among the most frequently studied polyphenols. Of these, caffeic acid esters predominate, and 5-O-caffeoylquinic acid (5-CQA) is their main and most widespread representative. Recently performed studies have shown that after removing water from the aqueous solution of 5-CQA, its dry residue contains two hydrates of this compound, each consisting of two 5-CQA molecules and two molecules of H2O (2 × 5-CQA*2xH2O). The results presented in the paper not only define the characteristic features of 5-CQA but, more importantly, offer solid evidence that 5-CQA hydrates begin to form already in the aqueous solution of 5-CQA immediately after the dissolution of this compound and that the analogous process can occur in food products containing 5-CQA during their storage. Moreover, the performed experiments indicate the validity of the hypothesis that 5-CQA hydrates are formed by active collisions of 5-CQA molecules with monomeric/dimeric water molecules existing in trace amount in strongly associated aqueous systems. The presence of 5-CQA hydrates in liquid food products may have a significant impact on the assessment of some of their physicochemical properties as well as their biochemical activity.

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.

High-Resolution Liquid Chromatography-Mass Spectrometry-Based Metabolomics for the Classification of Chuquiraga (Barnadesioideae, Asteraceae): New Phenylpropanoid Derivatives as Chemical Markers for Chuquiraga spinosa.

Despite their relatively poorly investigated phytochemistry, species of the genus Chuquiraga are widely commercialized. The present study reports the use of a high-resolution liquid chromatography-mass spectrometry-based metabolomics approach coupled with exploratory and supervised multivariate statistical analyses for species classification and chemical marker identification of four species of Chuquiraga (C. jussieui, C. weberbaueri, C. spinosa, and Chuquiraga sp.) from Ecuador and Peru. Based on these analyses, a high percentage of correct classifications (87% to 100%) allowed the prediction of the taxonomic identity of Chuquiraga species. Through the metabolite selection process, several key constituents with the potential to be chemical markers were identified. Samples of C. jussieui displayed alkyl glycosides and triterpenoid glycosides as discriminating metabolites, while Chuquiraga sp. displayed high concentrations of p-hydroxyacetophenone, p-hydroxyacetophenone 4-O-glucoside, p-hydroxyacetophenone 4-O-(6-O-apiosyl)-glucoside, and quinic acid ester derivatives as the main metabolites. Caffeic acid was characteristic for C. weberbaueri samples, whereas C. spinosa displayed higher concentrations of the following new phenylpropanoid ester derivatives: 2-O-caffeoyl-4-hydroxypentanedioic acid (24), 2-O-p-coumaroyl-4-hydroxypentanedioic acid (34), 2-O-feruloyl-4-hydroxypentanedioic acid (46), 2,4-O-dicaffeoylpentanedioic acid (71), and 2-O-caffeoyl-4-O-feruloylpentanedioic acid (77).

The downside of metabolic diversity: Postingestive rearrangements by specialized insects

Deploying toxins in complex mixtures is thought to be advantageous and is observed during antagonistic interactions in nature. Toxin mixtures are widely utilized in medicine and pest control, as they are thought to slow the evolution of detoxification counterresponses in the targeted organisms. Here we show that caterpillars rearrange key constituents of two distinct plant defense pathways to postingestively disable the defensive properties of both pathways. Specifically, phenolic esters of quinic acid, chlorogenic acids (CAs), potent herbivore and ultraviolet (UV) defenses, are reesterified to decorate particular sugars of 17-hydroxygeranyllinalool diterpene glycosides (HGL-DTGs) and prevent their respective anti–herbivore defense functions. This was discovered through the employment of comparative metabolomics of the leaves of Nicotiana attenuata and the frass of this native tobacco’s specialist herbivore, Manduca sexta larvae. Feeding caterpillars on leaves of transgenic plants abrogated in each of the two pathways, separately and together, revealed that one of the fully characterized frass conjugates, caffeoylated HGL-DTG, originated from ingested CA and HGL-DTGs and that both had negative effects on the defensive function of the other compound class, as revealed by rates of larval mass gain. This negative defensive synergy was further explored in 183 N. attenuata natural accessions, which revealed a strong negative covariance between the two defense pathways. Further mapping analyses in a biparental recombinant inbred line (RIL) population imputed quantitative trait loci (QTLs) for the two pathways at distinct genomic locations. The postingestive repurposing of defense metabolism constituents reveals a downside of deploying toxins in mixtures, a downside which plants in nature have evolved to counter.

Predictive Multi Experiment Approach for the Determination of Conjugated Phenolic Compounds in Vegetal Matrices by Means of LC-MS/MS.

Polyphenols (PCs) are a numerous class of bioactive molecules and are known for their antioxidant activity. In this work, the potential of the quadrupole/linear ion trap hybrid mass spectrometer (LIT-QqQ) was exploited to develop a semi-untargeted method for the identification of polyphenols in different food matrices: green coffee, Crocus sativus L. (saffron) and Humulus lupulus L. (hop). Several conjugate forms of flavonoids and hydroxycinnamic acid were detected using neutral loss (NL) as a survey scan coupled with dependent scans with enhanced product ion (EPI) based on information-dependent acquisition (IDA) criteria. The presented approach is focused on a specific class of molecules and provides comprehensive information on the different conjugation models that are related to specific base molecules, thus allowing a quick and effective identification of all possible combinations, such as mono-, di-, or tri-glycosylation or another type of conjugation such as quinic acid esters.

Comparison of the Phytochemical Variation of Non-Volatile Metabolites within Mother Tinctures of Arnica montana Prepared from Fresh and Dried Whole Plant Using UHPLC-HRMS Fingerprinting and Chemometric Analysis.

Arnica montana L. has been recognized for centuries as an herbal remedy to treat wounds and promote healing. It also has a long tradition of use in homeopathy. Depending on its medicinal utilization, standardization regulations allow different manufacturing processes, implying different raw materials, such as the whole arnica plant in its fresh or dried state. In this study, an untargeted metabolomics approach with UHPLC-HRMS/MS was used to cross-compare the phytochemical composition of mother tinctures of A. montana that were prepared from either fresh whole plant (fMT) matter or from oven-dried whole plant (dMT) matter. The multivariate data analysis showed significant differences between fMT and dMT. The dereplication of the HRMS and MS/MS spectra of the more discriminant compounds led to annotated quinic acid, dicaffeoyl quinic acids, ethyl caffeate, thymol derivatives and dehydrophytosphingosine, which were increased in fMT, while Amadori rearrangement products (ARP) and methoxyoxaloyl-dicaffeoyl quinic acid esters were enhanced in dMT. Neither sesquiterpene lactones nor flavonoids were affected by the drying process. This is the first time that a sphingosine, ethyl caffeate and ARP are described in A. montana. Moreover, putative new natural products were detected as 10-hydroxy-8,9-epoxy-thymolisobutyrate and an oxidized proline fructose conjugate, for which isolation and full structure elucidation will be necessary to verify this finding.

Agronomic and Metabolomic Side-Effects of a Divergent Selection for Indol-3-Ylmethylglucosinolate Content in Kale (Brassica oleracea var. acephala).

Brassica oleracea var. acephala (kale) is a cruciferous vegetable widely cultivated for its leaves and flower buds in Europe and a food of global interest as a “superfood”. Brassica crops accumulate phytochemicals called glucosinolates (GSLs) which play an important role in plant defense against biotic stresses. Studies carried out to date suggest that GSLs may have a role in the adaptation of plants to different environments, but direct evidence is lacking. We grew two kale populations divergently selected for high and low indol-3-ylmethylGSL (IM) content (H-IM and L-IM, respectively) in different environments and analyzed agronomic parameters, GSL profiles and metabolomic profile. We found a significant increase in fresh and dry foliar weight in H-IM kale populations compared to L-IM in addition to a greater accumulation of total GSLs, indole GSLs and, specifically, IM and 1-methoxyindol-3-ylmethylGSL (1MeOIM). Metabolomic analysis revealed a significant different concentration of 44 metabolites in H-IM kale populations compared to L-IM. According to tentative peak identification from MS interpretation, 80% were phenolics, including flavonoids (kaempferol, quercetin and anthocyanin derivates, including acyl flavonoids), chlorogenic acids (esters of hydroxycinnamic acids and quinic acid), hydroxycinnamic acids (ferulic acid and p-coumaric acid) and coumarins. H-IM kale populations could be more tolerant to diverse environmental conditions, possibly due to GSLs and the associated metabolites with predicted antioxidant potential.

Differentiating Pu-erh raw tea from different geographical origins by 1 H-NMR and U-HPLC/Q-TOF-MS combined with chemometrics.

Pu-erh tea is believed to be a beneficial beverage for health due to its many kinds of pharmacological effects. Nevertheless, detailed information related to differences in metabolites of Pu-erh raw tea from different geographical origins remains scarce. In this study, 43 elements were found in water-soluble components of Pu-erh raw tea by highly sensitive ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (U-HPLC/Q-TOF-MS). The characteristic groups of 29 metabolites from nondestructive proton nuclear magnetic resonance (1 H-NMR) spectroscopy were assigned. The variables contributed largely to the origin classification, mainly including valine, threonine, chlorogenic acid, quinic acid, epiafzelechin, and gallic acid ester, were screened out by sparse partial least squares discriminant analysis (sPLS-DA) method. This study provided a feasible and rapid technique for distinguishing Pu-erh tea from different areas by 1 H-NMR combined with sPLS-DA.

FLAVONOIDS AND PHENILPROPANOIDS OF THE ABOVE GROUND ORGANS OF THE BUPLEURUM MUL-TINERVE DC. OF THE FLORA OF THE BAIKAL REGION

A study of the flavonoids and phenylpropanoids of the aerial organs of Bupleurum multinerve was carried out. Samples of raw materials were collected in the Baikal region in the vicinity of. Verkholensk, Irkutsk region. The raw materials were collected during the flowering period in 2019 in the herb-grass association. For analysis, raw materials were extracted with 70% ethyl alcohol in an ultrasonic bath for 30 minutes, followed by centrifugation of the extract. Compounds were identified by the UPLC-DAD-ESI-MS method in comparison with standard samples. In the aerial organs of B. multinerve, 15 compounds were identified (8 flavonoids and 7 phenylpropanoids). Flavonoids B. multinerve are derivatives of quercetin, kempferol, isoramnetin; phenylpropanoids – esters of quinic acid with coffee, ferulic, coumaric. The contents of B. multinerve compounds were first established: quercetin-3-O-glucuronide, kempferol-3-O-glucoside (astragaline), 5-O-p-coumaroylquinic acid, 5-O-feruloylquinic acid, 3-O-feruloylquinic acid, 3,5-di-O-caffeoylquinic acid; 4,5-di-O-caffeoylquinic acid. The quantitative content of glycosides of flavonoids isoramnetin-3-O-rutinoside (narcissin) 20.74 mg/g, quercetin-3-O-rutinoside (rutin) 19.53 mg/g, quercetin-3 was determined by MK-HPLC-UV in the aerial organs of B. multinerve -O-glucoside (isocvercitrin) 2.24 mg/g, camperol-3-O-glucoside (astragaline) 0.39 mg/g, quercetin-3-O-glucuronide 0.25 mg/g; quercetin flavonoid aglycones 0.43 mg/g; isoramnetin 0.53 mg/g; the predominant phenylpropanoids were 5-O-caffeoylquinic acid 6.60 mg/g, 3,5-di-O-caffeylquinic acid 1.58 mg/g. The total content of identified flavonoids was 44.97 mg/g, phenylpropanoids 9.53 mg/g.

Application of Chemometrics Tools to the Study of the Fe(III)-Tannic Acid Interaction.

Chemometric techniques were applied to the study of the interaction of iron(III) and tannic acid (TA). Modeling the interaction of Fe(III)–TA is a challenge, as can be the modeling of the metal complexation upon natural macromolecules without a well-defined molecular structure. The chemical formula for commercial TA is often given as C76H52O46, but in fact, it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of galloyl moieties per molecule ranging from 2 up to 12. Therefore, the data treatment cannot be based on just the stoichiometric approach. In this work, the redox behavior and the coordination capability of the TA toward Fe(III) were studied by UV-vis spectrophotometry and fluorescence spectroscopy. Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and Parallel Factor Analysis (PARAFAC) were used for the data treatment, respectively. The pH range in which there is the redox stability of the system Fe(III)–TA was evaluated. The binding capability of TA toward Fe(III), the spectral features of coordination compounds, and the concentration profiles of the species in solution as a function of pH were defined. Moreover, the stability of the interaction between TA and Fe(III) was interpreted through the chemical models usually employed to depict the interaction of metal cations with humic substances and quantified using the concentration profiles estimated by MCR-ALS.

Mass Spectrometry and 1H-NMR Study of Schinopsis lorentzii (Quebracho) Tannins as a Source of Hypoglycemic and Antioxidant Principles.

The ethyl acetate extract of the commercial tannin Tan’Activ QS-SOL (from Schinopsis lorentzii wood), employed for the production of red wine, was subjected to chromatography on Sephadex LH-20, providing nine fractions (A-1–A-9), which were estimated for total phenols content (GAE), antioxidant activity (DPPH, ORAC), and hypoglycemic activity (α-glucosidase and α-amylase inhibition). All the fractions were analyzed by means of HPLC/ESI-MS/MS and 1H-NMR to identify the principal active constituents. Fractions A-1 and A-3 showed the highest antioxidant activity and gallic acid (1), pyrogallol (3), eriodictyol (6), catechin (12), and taxifolin (30) were identified as the major constituents. The highest α-glucosidase and α-amylase inhibitory activity was observed in fractions A-7–A-9 containing condensed (9′, 15, 18, 19, 23, and 27) hydrolysable tannins (13 and 32) as well as esters of quinic acid with different units of gallic acid (5, 11, 11′, 14, and 22). This last class of gallic acid esters are here reported for the first time as α-glucosidase and α-amylase inhibitors.

Sunflower (Helianthus annuus L.) Plants at Various Growth Stages Subjected to Extraction-Comparison of the Antioxidant Activity and Phenolic Profile.

The aim of this study was to evaluate the differences in the antioxidant activity and phenolic profile of sunflower (Helianthus annuus L.) extracts obtained from the aerial parts of plants harvested at five growth stages. In vitro assays were used to determine the antioxidant activity, i.e., ABTS•+ and DPPH• scavenging activity, the ferric-reducing antioxidant power (FRAP) and the ability to inhibit β-carotene–linoleic acid emulsion oxidation. Phenolic compounds, such as mono- and dicaffeoylquinic acid isomers and caffeic acid hexose, were identified using the LC–TOF–MS/MS technique. The predominant compound during the growth cycle of the plant was 3,5-di-O-caffeoylquinic acid, whose content was the highest at the mid-flowering stage. The total phenolic content was also the highest in sunflowers at the mid-flowering stage. The main phenolic compound contents were closely correlated with ABTS•+ and DPPH• scavenging activity and FRAP. No significant correlation was found between the total phenolic content and the antioxidant activity in the emulsion system. The highest antiradical activity and FRAP were generally determined in older plants (mid-flowering and late flowering stages). In conclusion, the aerial parts of sunflowers, in particular those harvested at the mid-flowering stage, are a good plant material from which to obtain phenolic compound extracts, albeit mainly of one class (esters of caffeic acid and quinic acid), with high antioxidant activity.

Caffeic acid: a brief overview of its presence, metabolism, and bioactivity

Caffeic acid is a bioactive compound found in a variety of plants including vegetables, fruits, herbs, and drinks. It belongs to the huge group of chemicals called polyphenols and is a major representative of the polyphenol subgroup of hydroxycinnamic acids. In foods, caffeic acid occurs mostly as a quinic acid ester called chlorogenic acid. Caffeic acid, like other polyphenols, is believed to exhibit many health benefits associated with their antioxidant properties, including the prevention of inflammation, cancer, neurodegenerative diseases, and diabetes. Nowadays, the use of naturally occurring bioactive substances, including caffeic acid, is becoming a very common phenomenon. Thus, information about their functions and properties is very important.Keywords: caffeic acid, polyphenols, bioactive compound, oxidative stress

Phenolic compounds from Nerium oleander leaves: microwave assisted extraction, characterization, antiproliferative and cytotoxic activities.

A microwave-assisted extraction (MAE) method was used for the extraction of phenolic compounds from Nerium oleander leaves. The influence of variables such as ethanol concentration, microwave power, irradiation time and liquid/solid ratio on polyphenol extraction was modelled using a second-order regression equation based on response surface methodology (RSM). The optimal conditions for MAE were: extraction solvent 35% ethanol concentration, 500 W microwave power, 60 s irradiation time and a solvent/material ratio of 20 mL g-1. Under optimal MAE conditions, the recovery of TPC was 25.752 mg GAE per g dw. 19 compounds have been identified by HPLC-ESI-MS/MS analysis; the main compounds identified were chlorogenic acid, rutin and quinic acid esters, such as caffeoylquinic acids and dicaffeoylquinic acids. Additionally, the optimized extract demonstrated potential to inhibit HT29 colorectal cancer cell growth (EC50 = 2.432 μg mL-1) without presenting cytotoxicity in confluent Caco-2 cells, a model of human intestinal epithelium. These results supply new information about the phenolic composition of Nerium oleander leaves and their antiproliferative effect.

Quinic acid esters from Erycibe obtusifolia with antioxidant and tyrosinase inhibitory activities

A new quinic acid derivative, 3-O-syringoylquinic acid methyl ester (1), along with eight known quinic acid derivatives (2-9), three coumarins (10-12), one phenylpropanoid (13), three feruloyltyramine derivatives (14-16), one lignan (17) and two isoflavones (18-19) were isolated from an ethyl acetate-soluble fraction of the roots and stems of Erycibe obtusifolia. The structure was elucidated on the basis of spectroscopic methods such as 1D and 2D-NMR, including HR-ESI-MS spectrometry. All of these compounds were investigated for their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and inhibitory effects on mushroom tyrosinase. Compounds 2–9, quinic acid derivatives with caffeoyl moiety, showed significant DPPH radical scavenging activity. Moreover, compounds 2 and 5–10 showed weak mushroom tyrosinase inhibitory effects.

Metabolomic Profiling of the Host Response of Tomato (Solanum lycopersicum) Following Infection by Ralstonia solanacearum.

Tomato (Solanum lycopersicum) is an important dietary source of bioactive phytochemicals and active breeding programs constantly produce new cultivars possessing superior and desirable traits. The phytopathogenic Ralstonia solanacearum, the causal agent of bacterial wilt, is a highly destructive bacterial disease with a high economic impact on tomato production. This study followed an untargeted metabolomic approach involving four tomato cultivars and aimed at the identification of secondary metabolites involved in plant defense after infection with R. solanacearum. Liquid chromatography coupled to mass spectrometry (LC-MS) in combination with multivariate data analysis and chemometric modelling were utilized for the identification of discriminant secondary metabolites. The total of 81 statistically selected features were annotated belonging to the metabolite classes of amino acids, organic acids, fatty acids, various derivatives of cinnamic acid and benzoic acids, flavonoids and steroidal glycoalkaloids. The results indicate that the phenylpropanoid pathway, represented by flavonoids and hydroxycinnamic acids, is of prime importance in the tomato defense response. The hydroxycinnamic acids esters of quinic acid, hexoses and glucaric acids were identified as signatory biomarkers, as well as the hydroxycinnamic acid amides to polyamines and tyramine. Interestingly, the rapid and differential accumulation of putrescine, dopamine, and tyramine derivatives, along with the presence of a newly documented metabolite, feruloyl serotonin, were documented in the infected plants. Metabolite concentration variability in the different cultivar tissues point to cultivar-specific variation in the speed and manner of resource redistribution between the host tissues. These metabolic phenotypes provide insights into the differential metabolic signatures underlying the defense metabolism of the four cultivars, defining their defensive capabilities to R. solanacearum.

Phenolic Profile of Artemisia alba Turra.

The aim of this study was to evaluate flower and leaf methanol extracts of Artemisia alba Turra for their total phenolic and flavonoid contents, antioxidant capacity and to investigate their phenolic composition. The flower extract was richer in total phenolics and flavonoids and possessed higher antioxidant activity through DPPH and ABTS assays. The UHPLC-PDA-MS analysis of the flower and leaf methanol extracts revealed similar phenolic profile and allowed identification of 31 phenolic compounds (flavonoids, coumarins, and phenolic acids) by comparison with the respective reference compounds or tentatively characterized by their chromatographic behavior, UV patterns, and MS fragmentations. The presence of hispidulin, jaceosidin, desmethoxycentaureidin, and dicaffeoyl esters of quinic acid in A.alba is reported herein for the first time. The distribution of flavonoids in A.alba from different origins was discussed from chemotaxonomic point of view.

Chlorogenic acids – their properties, occurrence and analysis

<p>Chlorogenic acids (CQAs), the esters of caffeic acid and quinic acid, are biologically important phenolic compounds present in many plant species. Nowadays much is known from their pro-health properties, including anti-cancer activity. Yet, the supposition that they may be helpful in fighting obesity and modify glucose-6-phosphatase involved in glucose metabolism have led to a revival of research on CQAs properties and their natural occurrence. Much attention is also paid to the proper analysis of CQAs content in plants and plant products due to the fact that the main CQAs representative in nature <em>i.e.</em> 5-<em>O</em>-caffeoylquinic acid (5-CQA) is commonly employed as a quality marker in the control of various natural products.</p><p>The common procedures used so far for CQAs determination in plants involve conventional long lasting solvent extraction realized at higher temperatures prior to chromatographic analysis. The drawbacks associated to the conventional extraction techniques have led to the search for new alternative extraction processes that additionally could improve extracts quality. The latter is particularly important as regards CQAs applications, and the fact that these compounds easily transform/degrade to others. According to reports, the conventional heating of 5-CQA in the presence of water causes its isomerization and transformation. The reports prove that 5-CQA not only isomerizes to 3- and 4-<em>O</em>-caffeoylquinic acid, but also undergoes other transformations such as esterification and reactions with water. Hence, in the attempt to improve the process of chlorogenic acids extraction and to make it more effective and environmentally friendly, innovative so-called "enhanced" techniques of extraction have been recently developed and applied. To guarantee the proper analysis of compounds with very similar properties forming the chlorogenic acids family and their numerous transformation/degradation products, hyphenated techniques, in particular LC-MS, are currently being used.</p>

Green coffee seed residue: A sustainable source of antioxidant compounds

Oil extraction from green coffee seeds generates residual mass that is discarded by agribusiness and has not been previously studied. Bioactive secondary metabolites in coffee include antioxidant phenolic compounds, such as chlorogenic acids. Coffee seeds also contain caffeine, a pharmaceutically important methylxanthine. Here, we report the chemical profile, antioxidant activity, and cytotoxicity of hydroethanolic extracts of green Coffea arabica L. seed residue. The extracts of the green seeds and the residue have similar chemical profiles, containing the phenolic compounds chlorogenic acid and caffeine. Five monoacyl and three diacyl esters of trans-cinnamic acids and quinic acid were identified by ultra-performance liquid chromatography/electrospray ionization-quadruple time of flight mass spectrometry. The residue extract showed antioxidant potential in DPPH, ABTS, and pyranine assays and low cytotoxicity. Thus, coffee oil residue has great potential for use as a raw material in dietary supplements, cosmetic and pharmaceutical products, or as a source of bioactive compounds.

Synthesis of new dicinnamoyl 4-deoxy quinic acid and methyl ester derivatives and evaluation of the toxicity against the pea aphid Acyrthosiphon pisum.

New dicinnamoyl (caffeoyl, feruloyl, ortho and para-coumaroyl) 4-deoxyquinic acid and esters were synthesized by using a new 4-deoxy quinic acid triol intermediate. The optimisation of both coupling and deprotection steps allowed the preparation in good yields of the target products either as the carboxylic acid or the methyl ester form. Eight new compounds were evaluated for their ability to influence the feeding behaviour of the pea aphid Acyrthosiphon pisum. Artificial diet bioassays showed that two compounds are toxic (mortality and growth inhibition) at lower concentrations than the reference 3,5-dicaffeoyl quinic acid.