Caffeic Acid Esters Research Articles

Protective effects of rosmarinic acid against radiation-induced damage to the hematopoietic system in mice.

Rosmarinic acid (RA) is an ester of caffeic acid and 3, 4-dihydroxyphenyl lactic acid. It is a potent antioxidant that functions by scavenging free radicals. Here, we used a 30-day survival assay to investigate the radioprotective effects of RA. Mice were treated with RA once per day for 10 consecutive days starting at 3 days before gamma irradiation at 7.5 Gy until 7 days post irradiation. Mice treated with 100 and 200 mg/kg body weight (bw) of RA had 30-day survival rates of 89% and 72%, respectively, compared with 32% in the control group, and the differences were statistically significant (P = 0.0008 and 0.0421, respectively). Spleen colony–forming units (CFU-S), the number of nucleated cells in the bone marrow (BMNC), bone marrow DNA content, and hematological parameters of the peripheral blood were measured to investigate the radioprotective effect of RA on the hematopoietic system. The treatment groups that received RA at 50, 100 and 150 mg/kg bw and whole-body exposure to 5.5 Gy of 137Cs γ- radiation had significantly higher CFU-S, BMNC and DNA content than the irradiation-only group. Assessment of hematological parameters in the peripheral blood showed that the treatment groups receiving RA at doses of 50, 100 and 150 mg/kg bw had higher white blood cell counts, hemoglobin and platelets than the radiation-only group. These results suggested that the administration of RA promoted the recovery of peripheral blood cells in irradiated mice.

Methyl jasmonate enhanced production of rosmarinic acid in cell cultures of Satureja khuzistanica in a bioreactor

The growing interest in rosmarinic acid (RA), an ester of caffeic acid and 3,4‐dihydroxyphenyl lactic acid, is due to its biological activities, which include cognitive‐enhancing effects, slowing the development of Alzheimer's disease, cancer chemoprotection, and anti‐inflammatory activity. Inspired by the challenge of meeting the growing demand for this plant secondary metabolite, we developed a biotechnological platform based on cell suspension cultures of Satureja khuzistanica. The high amounts of RA produced by this system accumulated mainly inside the cells. To further improve production, two elicitors, 100 μM methyl jasmonate (MeJA) and 40 mM cyclodextrin (CD), were tested, separately and together. MeJA increased RA productivity more than 3‐fold, the elicited cultures achieving an RA production of 3.9 g L−1 without affecting biomass productivity. CD did not have a clear effect on RA production, and under the combined treatment of MeJA + CD only a small amount of RA was released to the medium. When the cell culture was transferred from a shake flask to a wave‐mixed bioreactor, a maximum RA production of 3.1 g L−1 and biomass productivity of 18.7 g L−1 d−1 was achieved under MeJA elicitation, demonstrating the suitability of S. khuzistanica cell suspensions for the biotechnological production of this bioactive plant secondary metabolite.

Identification and Characterization of Five BAHD Acyltransferases Involved in Hydroxycinnamoyl Ester Metabolism in Chicory.

Chicory (Cichorium intybus) accumulates caffeic acid esters with important significance for human health. In this study, we aim at a better understanding of the biochemical pathway of these bioactive compounds. Detailed metabolic analysis reveals that C. intybus predominantly accumulates caftaric and chicoric acids in leaves, whereas isochlorogenic acid (3,5-diCQA) was almost exclusively accumulated in roots. Chlorogenic acid (3-CQA) was equally distributed in all organs. Interestingly, distribution of the four compounds was related to leaf age. Induction with methyljasmonate (MeJA) of root cell suspension cultures results in an increase of 3-CQA and 3,5-diCQA contents. Expressed sequence tag libraries were screened using members of the BAHD family identified in Arabidopsis and tobacco as baits. The full-length cDNAs of five genes were isolated. Predicted amino acid sequence analyses revealed typical features of BAHD family members. Biochemical characterization of the recombinant proteins expressed in Escherichia coli showed that two genes encode HCTs (hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyltransferases, HCT1 and HCT2) whereas, three genes encode HQTs (hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferases, HQT1, HQT2, and HQT3). These results totally agreed with the phylogenetic analysis done with the predicted amino acid sequences. Quantitative real-time polymerase chain reaction analysis of gene expression indicated that HQT3, HCT1, and HCT2 might be more directly associated with CQA accumulation in cell culture in response to MeJA elicitation. Transient expression of HCT1 and HQT1 in tobacco resulted in a higher production of 3-CQA. All together these data confirm the involvement of functionally redundant genes in 3-CQA and related compound synthesis in the Asteraceae family.

Acute rosmarinic acid treatment enhances long-term potentiation, BDNF and GluR-2 protein expression, and cell survival rate against scopolamine challenge in rat organotypic hippocampal slice cultures

BackgroundRosmarinic acid (RA) is a polyphenolic ester of caffeic acid and is commonly found in the Nepetoideae subfamily of flowering mint plants. Because RA has previously exhibited antioxidant, neuroprotective, and antidepressant-like effects, we evaluated its influences on cellular functions in neuronal cultures. ObjectiveTo elucidate possible mechanisms of RA, we investigated the influences of acute RA administration on long-term potentiation (LTP), plasticity-related protein expression, and scopolamine-induced cell death in organotypic hippocampal slice cultures. MethodsLTP analysis in organotypic hippocampal slice cultures (OHSCs) was carried out with various ion channel blockers, such as AP5 (10 μM), CNQX (10 μM), niflumic acid (100 μM), and scopolamine (300 μM) in response to RA (1, 10 or 100 μg/mL) treatment. Protein expression and cell death assays in the presence of scopolamine were examined to observe the effects of RA. For LTP analysis, baseline field excitatory postsynaptic potentials (fEPSPs) were recorded in CA1 by a 60-channel multielectrode array (MEA) every min for 40 min before 15 min of high-frequency stimulation (HFS) to the Schaffer collaterals and commissural pathways, followed by a successive 50 min of recording. For protein expression measurements, anti-BDNF and anti-GluR2 antibodies were used for Western blotting assays in whole-hippocampal tissue homogenate. Finally, for cell death assays, OHSCs were exposed to a culture medium containing propidium iodide (PI) for 24 or 48 h, followed by the assessment of cell death by fluorescent image analysis of PI uptake. Resultsand discussion: Our results indicate that RA treatment enhances fEPSPs following HFS in CA1 synapses at 1 and 10 μg/ml RA, an effect that was inhibited by CNQX and NFA but not by AP5. RA treatment also increases the expression of BDNF and GluR-2 proteins and prevents cell death of scopolamine-exposed OHSCs. Our results suggest the possibility that rosmarinic acid can enhance neural plasticity by modulating glutamatergic signaling pathways, as well as providing neuroprotection with reduced cholinergic activity.

Chlorogenic acid ameliorates intestinal mitochondrial injury by increasing antioxidant effects and activity of respiratory complexes

Dietary polyphenols are thought to be beneficial for human health by acting as antioxidants. Chlorogenic acid (CGA) is abundant in plant-based foods as an ester of caffeic acid and quinic acid. In this study, we investigated the effects of CGA on mitochondrial protection. Our results demonstrated that pretreatment with CGA ameliorated the intestinal mitochondrial injury induced by H2O2; membrane potential was increased, mitochondrial swelling, levels of reactive oxygen species, contents of 8-hydroxy-2-deoxyguanosine, and cytochrome c released were decreased. The beneficial effects of CGA were accompanied by an increase in antioxidant and respiratory-chain complex I, IV, and V activities. In trinitrobenzene-sulfonic acid-induced colitic rats indicated that CGA supplementation improved mitochondria ultrastructure and decreased mitochondrial injury. Our results suggest a promising role for CGA as a mitochondria-targeted antioxidant in combating intestinal oxidative injury. Daily intake of diets containing CGA, such as coffee and honeysuckle, may be useful for prevention of intestinal diseases.

The Effect of Rosmarinic Acid on Immunological and Neurological Systems: A Basic Science and Clinical Review

Rosmarinic acid (RosA) is an ester of caffeic acid and 3,4-dihydroxyphenylactic acid. RosA has a number of beneficial biological activities, including antiviral, antibacterial, anti-inflammatory, and antioxidant properties. Oxidative stress is recognized as a common factor in many neurodegenerative diseases and is a proposed mechanism for age-related degenerative processes as a whole. RosA has shown antioxidative action, acting as a scavenger of free radicals. RosA protects neurons from oxidative stress, significantly attenuated hydrogen peroxide-induced reactive oxygen species generation, and apoptotic cell death and could contribute at least in part to neuroprotective effects. RosA has also been shown to suppress immunoglobulin responses and inflammatory responses of polymorphonuclear leukocytes which may explain its effectiveness at treating seasonal allergic rhinoconjuctivitis in human clinical trials. The anti-inflammatory effects of RosA along with its immunomodulatory effects may also make it a novel agent for the treatment of auto-immune disorders. This review is focused on the effect of RosA on both immunological and neurological systems and its potential as a novel therapeutic agent for the treatment of associated conditions, especially those in which oxidative stress is a factor.

Chemo and regioselective serendipitous electrochemically initiated spirocyclization of caffeic acid esters with barbituric acid derivatives

An interesting sequence of oxidation/Michael addition/oxidation/spirocyclization is observed in the electrolysis of caffeic acid esters in the presence of barbituric acid derivatives leading to the synthesis of a series of novel spirocycles. In an experimentally simple and clean procedure, the electrolyses proceed via a domino of electrochemical (E) and chemical (C) events with employing electrons as the only reagents in aqueous solution without introducing any catalyst or oxidant. From mechanistic point of view, a new type of domino mechanism (ECECi, Ci=spirocyclization) is proven with a unique Ci phenomenon at final step. Also, in light of experimental and theoretical NMR investigations, highly chemo and regioselectivities have been detected in these synthetic electrolyses.

Establishment and characterization of a Satureja khuzistanica Jamzad (Lamiaceae) cell suspension culture: a new in vitro source of rosmarinic acid.

An in vitro approach to the production of rosmarinic acid (RA), a medicinally important caffeic acid ester, in a cell suspension culture (CSC) of Satureja khuzistanica Jamzad (Lamiaceae) has been investigated for the first time. The CSC was established from friable calli derived from shoot tip explants in Gamborg's B5 liquid medium supplemented with 30g/L sucrose, 20mg/L L-glutamine, 200mg/L casein hydrolysate, 5mg/L benzyladenine (BA) and 1mg/L indole-3-butyric acid (IBA). The effect of nitrogen source (KNO3 and (NH4)2SO4) and their different concentrations on the fresh and dry weight (g/L), as well as RA content (mg/g dry weight) were measured. CSC growth measurements indicated a maximum specific cell growth rate of 1.5/day, a doubling time of 7.6days and a high percentage of cell viability (96.4%) throughout the growth cycle. Maximum cell fresh weight (353.5g/L), dry weight (19.7g/L) and RA production (180.0mg/g) were attained at day 21 of culture. Cell growth and RA content were affected by nitrogen deficiency. Media containing 8.3mM of total nitrogen (¼ of B5 standard medium) led to a minimum cell fresh weight (243.0g/L), dry weight (17.4g/L) and RA content (38.0mg/g) after 21 days. The established CSC provided useful material for further optimization experiments aimed at a large-scale production of RA.

Species-specific differences in synthesis of flavonoids and phenolic acids under increasing periods of enhanced blue light

Species-specific differences in synthesis of flavonoids and phenolic acids were studied under lengthening periods of enhanced blue light in a greenhouse experiment in Northern Finland in the autumn of 2012. The aim was to compare red- and blue- weighted light spectra in relation to biosynthesis of the compounds. The species studied were red leaf lettuce and basil. There were five treatments for these inter-lighting LED manipulations using traditional high pressure sodium lamps as background light sources. Two treatments were exposed for the entire experimental period with (1) red- and (2) blue- weighted light for 48 days. The other three treatments were initiated with red- weighted light, but after each subsequent 12 day sub-period, one red-weighted treatment was switched to blue, resulting in the following treatments: 48, 36, 24, 12 and 0 days under enhanced blue light. Flavonoid and phenolic acid biosynthesis in plants were found to be species dependent. The most abundant compound in red leaf lettuce was cichoric acid (a dicaffeoyltartaric acid) while rosmaric acid (an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid) dominated in basil. Other compounds detected also varied between the species. Red leaf lettuce was much more responsive to supplemental blue light. Based on these results, it is suggested that both blue and red light may be needed to regulate the accumulation of phenolics in basil. Some of the compounds detected accumulated continuously as a function of the spent time under supplemental blue light in red leaf lettuce, but not in basil.

The cellular protective effects of rosmarinic acid: from bench to bedside.

Rosemary (Rosmarinus officinalis L.) is one of the most common household herbs, used as spices in a variety of foods, and employed in traditional medicine for its healing properties. Rosemary is a rich source of active antioxidant constituents such as phenolic diterpenes, flavonoids and phenolic acids. Caffeic acid and rosmarinic acid are the most important bioactive constituents. Rosmarinic acid is the ester of caffeic acid and 3,4-dihydroxyphenyllactic acid and is widely identified in different plant species. Chemical structure of rosmarinic acid contains two phenolic rings: one of them is derived from phenylalanine via caffeic acid and the other from tyrosine via dihydroxyphenyl-lactic acid. Its large-scale production is obtained from plant cell cultures of Coleus blumei Benth. It is easily absorbed through gastrointestinal tract as well as the skin. Rosmarinic acid is one of the most important and well known natural antioxidant compounds, which possesses neuroprotective effects in different models of neuroinflammation, neurodegeneration, as well as chemicalinduced neurotoxicity and oxidative stress. Therefore, in present review, we aim to discuss about chemistry, sources, biotechnological production and neuroprotective actions of rosmarinic acid with emphasis on its possible molecular mechanisms of neuroprotection.

Rosmarinic Acid Attenuates Sodium Taurocholate-Induced Acute Pancreatitis in Rats by Inhibiting Nuclear Factor-κB Activation.

Rosmarinic Acid (RA), a caffeic acid ester, has been shown to exert anti-inflammation, anti-oxidant and antiallergic effects. Our study aimed to investigate the effect of RA in sodium taurocholate ( NaTC )-induced acute pancreatitis, both in vivo and in vitro. In vivo, RA (50 mg/kg) was administered intraperitoneally 2 h before sodium taurocholate injection. Rats were sacrificed 12 h, 24 h or 48 h after sodium taurocholate injection. Pretreatment with RA significantly ameliorated pancreas histopathological changes, decreased amylase and lipase activities in serum, lowered myeloperoxidase activity in the pancreas, reduced systematic and pancreatic interleukin-1 β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) levels, and inhibited NF-κB translocation in pancreas. In vitro, pretreating the fresh rat pancreatic acinar cells with 80 μ mol/L RA 2 h before 3750 nmol/L sodium taurocholate or 10 ng/L TNF-α administration significantly attenuated the reduction of isolated pancreatic acinar cell viability and inhibited the nuclear activation and translocation of NF-κB. Based on our findings, RA appears to attenuate damage in sodium taurocholate-induced acute pancreatitis and reduce the release of inflammatory cytokines by inhibiting the activation of NF-κB. These findings might provide a basis for investigating the therapeutic role of RA in managing acute pancreatits.

Propolis in Dogs: Clinical Experiences and Perspectives (A Brief Review)

In light of the scarcity of novel therapeutic agents that are effective, the pharmaceutical industry has found a newer source of therapeutic compounds in natural products and herbal medicine to address the current health problems in humans and animals. What is particularly promising about these agents is that they produce fewer side effects and are more cost effective than synthetic compounds. This means greater availability of these treatments particularly for less developed countries who can’t afford expensive treatments. The reduced side effects also mean greater patient tolerance and increased compliance thereby yielding maximal therapeutic effect without negatively impacting on quality of life. Among the natural products more frequently employed nowadays is propolis, a resin that is routinely collected by bees (Apis mellifera). Propolis contains flavonoids, caffeic acid esters and diterpenic acids, which provide the bactericidal, antiviral and antifungal properties to this product. The use of propolis to address a variety of conditions in small animal species is beginning to play an important role in the currently available treatments. Its use appears to be an effective treatment with no side effects at low cost. This paper reviews the different applications of this compound to treat diseases in dogs.

Lipophilic modification enhances anti-colitic properties of rosmarinic acid by potentiating its HIF-prolyl hydroxylases inhibitory activity

Inhibition of hypoxia inducible factor-prolyl hydroxylase-2 (HPH), leading to activation of hypoxia inducible factor (HIF)-1 is a potential therapeutic strategy for the treatment of colitis. Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid is a naturally occurring polyphenolic compound with two catechols, a or inhibition of HPH. To improve accessibility of highly hydrophilic RA to HPH, an intracellular target, RA was chemically modified to decrease hydrophilicity. Of the less-hydrophilic derivatives, rosmarinic acid methyl ester (RAME) most potently inhibited HPH. Accordingly, RAME prevented hydroxylation of HIF-1α and consequently stabilized HIF-1α protein in cells. RAME inhibition of HPH and induction of HIF-1α were diminished by elevated doses of the required factors of HPH, 2-ketoglutarate and ascorbate. RAME induction of HIF-1α led to activation of an ulcer healing pathway, HIF-1-vascular endothelial growth factor (VEGF), in human colon carcinoma cells. RAME administered rectally ameliorated TNBS-induced rat colitis and substantially decreased the levels of pro-inflammatory mediators in the inflamed colonic tissue. In parallel with the cellular effects of RAME, RAME up-regulated HIF-1α and VEGF in the inflamed colonic tissue. Thus, lipophilic modification of RA improves its ability to inhibit HPH, leading to activation of the HIF-1-VEGF pathway. RAME, a lipophilic RA derivative, may exert anti-colitic effects via activation of the ulcer healing pathway.

Rosmarinic acid potentiates ATRA-induced macrophage differentiation in acute promyelocytic leukemia NB4 cells

Rosmarinic acid (RA, an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid) has a number of biological activities, but little is known about anti-leukemic activities of RA combined with all-trans retinoic acid (ATRA) against acute promyelocytic leukemia (APL) cells. We examined the differentiation marker, CD11b, in bone marrow cells (BMC) of an APL patient, in NB4 cells (APL cell line), and in normal BMC and peripheral blood mononuclear cells (PBMC) of healthy subjects by flow cytometric analysis. ATRA/RA induced expression of CD11b in the BMC of the APL patient and in NB4 cells, but not in normal BMC or PBMC. Therefore, we realized that RA potentiated ATRA-induced macrophage differentiation in APL cells. Further characterization of the induced macrophages showed that they exhibited morphological changes and were able to phagocytose and generate reactive oxygen species. Th also had typical expression of C–C chemokine receptor type 1 (CCR1), CCR2, and intercellular adhesion molecule-1 (ICAM-1). Moreover, the expression of CD11b+ and CD14+ cells depended on ERK-NF-κB axis activation. Together, these results indicate that RA potentiates ATRA-induced macrophage differentiation in APL cells. Thus, RA may play an important role as an appurtenant differentiation agent for functional macrophage differentiation in APL. Additionally, the differentiated macrophages might have a normal life span and, they could die. These data indicate that co-treatment with RA and ATRA has potential as an anti-leukemic therapy in APL.

Caffeic Acid Phenethyl Ester (CAPE) in Romanian Propolis

Introduction. Propolis is an important bee product, rich in biologically active compounds (MAƒrghitaș et al ., 2013). It is collected by the bees from buds and exudates of different trees and plants and it has been used since ancient times as a natural remedy or in embalming process. Caffeic acid phenethyl ester (CAPE) is one of the main medicinal components of propolis, possessing important biological activities, such as anti-bacterial, anti-oxidant anti-inflammatory and the most important anti-cancer properties (Son and Lewis, 2002). Aims. Taking into account that CAPE is an excellent compound in cancer, hepatitis and other oxidative stress diseases treatment; we consider that knowing the amount of this compound in Romanian propolis is a very challenging proposal. Materials and Methods. Different propolis samples were harvested in Transilvania, Romania, freeze immediately after harvest, finely ground, extracted with 70% ethylic alcohol and analyzed by high performance liquid chromatography. The measurements were done on a Shimadzu equipment, using acetonitril:water as mobile phase. To calculate the amount of CAPE in the samples, a calibration curve of different concentrations of standard compound was constructed. Results were expressed as mg/g propolis. Results: The analyzed propolis samples show that beside different phenolic acids and flavonoiuds, Romanian propolis is also rich in CAPE. Concentrations ranging from 0.86 to 3.87mgCAPE/g was measured and correlated with high amounts of chrysin. High concentrations of caffeic acid  (1.4 mg/ml) and pinocembrin (2.85 mg/g) were also determined in the analyzed samples. Conclusion. HPLC analysis of propolis samples from different locations in Romania, has highlighted the fact that they contain large amounts of CAPE. This propolis may be used successfully in the treatment of various diseases, including cancer. References MAƒrghitaș L., Dezmirean D. and Bobiș O. (2013). Important developments in Romanian propolis research, Evid. Based Complement. Alternat. Med., 2013:159392. Son S. And Lewis B.A. (2002). Free radical scavenging and antioxidative activity of caffeic acid amide and ester analogues: structure-activity relationship. J.Agric.Food Chem. 50:468-472.

A Rapid and Practical Catalytic Esterification for the Preparation of Caffeic Acid Esters

A convenient and practical catalytic method for the preparation of caffeic acid esters is reported. This esterification was carried out with high efficiency in the presence of ytterbium triflate in nitromethane without any other auxiliary reagents. The wide scope of application and especially the higher reactivity and more convenient procedure than previous methods make it a valuable application for the synthesis of caffeic acid esters and other cinnamic acid esters.

Protective Effects of Chlorogenic Acid against Experimental Reflux Esophagitis in Rats.

Esophageal reflux of gastric contents causes esophageal mucosal damage and inflammation. Recent studies show that oxygen-derived free radicals mediate mucosal damage in reflux esophagitis (RE). Chlorogenic acid (CGA), an ester of caffeic acid and quinic acid, is one of the most abundant polyphenols in the human diet and possesses anti-inflammatory, antibacterial and anti-oxidant activities. In this context, we investigated the effects of CGA against experimental RE in rats. RE was produced by ligating the transitional region between the forestomach and the glandular portion and covering the duodenum near the pylorus ring with a small piece of catheter. CGA (10, 30 and 100 mg/kg) and omeprazole (positive control, 10 mg/kg) were administered orally 48 h after the RE operation for 12 days. CGA reduced the severity of esophageal lesions, and this beneficial effect was confirmed by histopathological observations. CGA reduced esophageal lipid peroxidation and increased the reduced glutathione/oxidized glutathione ratio. CGA attenuated increases in the serum level of tumor necrosis factor-α, and expressions of inducible nitric oxide synthase and cyclooxygenase-2 protein. CGA alleviates RE-induced mucosal injury, and this protection is associated with reduced oxidative stress and the anti-inflammatory properties of CGA.

New trends in biotechnological production of rosmarinic acid.

Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyl lactic acid, is widely distributed in the plant kingdom. Interest in it is growing due to its promising biological activities, including cognitive-enhancing effects and slowing the development of Alzheimer's disease, cancer chemoprotection or anti-inflammatory activity, among others. In order to meet the increasing demand for this compound, several biotechnological approaches to its production based on plant cell and hairy root cultures have been developed. Empirical strategies are currently being combined with metabolic engineering tools to increase RA production in plant cell platforms in a more rational way. Discussed here are the latest advances in the field, together with recent trends in plant biotechnology, such as the application of single use technology and the use of biosensors in downstream processes.

Straightforward Enzyme-Catalyzed Asymmetric Synthesis of Caffeic Acid Esters in Enantioenriched Form

Enantiopure caffeic acid esters were successfully synthesized from caffeic acid and corresponding (R,S)-alcohol catalyzed by an immobilized lipase (Novozym 435) from Candida antarctica. Effects of the alcohol carbon chain length and the type of organic solvents were first investigated, and anhydrous isooctane was finally selected as the most suitable reaction medium. The optimal synthesis parameters for caffeic acid ester synthesis were evaluated using response surface methodology. The actual experimental conversions of 33.8 ± 1.8% and an E value of >100 for (R)-1-methylbutyl caffeate, achieved under optimized reaction conditions, indicated a good fit to the predictive model. Kinetic and thermodynamic analyses were conducted to determine the main factors affecting enantiomeric discrimination. Results from the batch reuse stability study show that the immobilized enzyme could be effectively reused. The present study is the first to use lipase as the chiral catalyst to prepare optically pure caffeic acid es...

Thermal transformation of trans-5-O-caffeoylquinic acid (trans-5-CQA) in alcoholic solutions

Chlorogenic acid (CQA), the ester of caffeic acid with quinic acid supplied to human organisms mainly with coffee, tea, fruit and vegetables, has been one of the most studied polyphenols. It is potentially useful in pharmaceuticals, food additives, and cosmetics due to its recently discovered biomedical activity, which revived interest in its properties, isomers and natural occurrence. We found that the heating of the alcoholic solution of trans-5-O-caffeoylquinic acid produced at least twenty compounds (chlorogenic acid derivatives and its reaction products with water and alcohol). The formation of three of them (methoxy, ethoxy and propoxy adducts) has not been reported yet. No reports exist either on methoxy adducts of 3- and 4-O-caffeoylquinic acid appearing in buffered methanol/water mixtures at pH exceeding 7. We observed that the amount of each formed component depended on the heating time, type of alcohol, its concentration in alcoholic/water mixture, and pH.