(-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid exerts anti-tumour effects against uveal melanoma through PI3K/AKT pathway.

PURPOSE: Uveal melanoma is the most common primary intraocular tumour in adults. There is no standard adjuvant treatment to prevent metastasis and no effective therapy in the metastatic setting. (-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid (QA) is a new compound isolated from the endophytic fungus Penicillium sp.FJ-1 of Avicennia marina, with potent activities to inhibit the PI3K. Our work further investigated effects of QA against uveal melanoma and explored its underlying mechanisms. METHODS: MP65 cells were treated with QA at different concentrations. CCK-8 assay was used to detect effects of QA on cell viability. PI staining was used to detect cell cycle arrest. Tumour model was established by injecting MP65 cells into nude mice subcutaneously. Tumour-bearing mice were divided into three groups (5 mice per group). Mice were treated with QA (5 or 10 mg/kg) or saline by intraperitoneal injection five times per week. RT-qPCR and western blot were used to detect the expression of genes and proteins, respectively. RESULTS: QA significantly inhibited the proliferation of uveal melanoma cells and induced the cell cycle arrest as well as autophagy. Moreover, QA treatment significantly slowed tumour growth of uveal melanoma, shown by decreased tumour volume and weight. Furthermore, QA treatment markedly decreased the protein expression of p-PI3K and p-AKT in tumour tissues. CONCLUSIONS: Our data provided scientific rationale to develop QA as a promising anti-tumour agent against uveal melanoma.

4,5 caffeoylquinic acid and scutellarin, identified by integrated metabolomics and proteomics approach as the active ingredients of Dengzhan Shengmai, act against chronic cerebral hypoperfusion by regulating glutamatergic and GABAergic synapses.

Dengzhan Shengmai (DZSM) is a proprietary Chinese medicine for remarkable curative effect as a treatment of cerebrovascular diseases, such as chronic cerebral hypoperfusion (CCH) and dementia based on evidence-based medicine, which have been widely used in the recovery period of ischemic cerebrovascular diseases. The purpose of this study was to investigate the active substances and mechanism of DZSM against CCH. Integrative metabolomic and proteomic studies were performed to investigate the neuroprotective effect of DZSM based on CCH model rats. The exposed components of DZSM in target brain tissue were analysed by a high-sensitivity HPLC-MS/MS method, and the exposed components were tested on a glutamate-induced neuronal excitatory damage cell model for the verification of active ingredients and mechanism of DZSM. Upon proteomic and metabolomic analysis, we observed a significant response in DZSM therapy from the interconnected neurotransmitter transport pathways including glutamatergic and GABAergic synapses. Additionally, DZSM had a significant regulatory effect on glutamate and GABA-related proteins including vGluT1 and vIAAT, suggested that DZSM could be involved in the vesicle transport of excitatory and inhibitory neurotransmitters in the pre-synaptic membrane. DZSM could also regulated the metabolism of arachidonic acid (AA), phospholipids, lysophospholipids and the expression of phospholipase A2 in post-synaptic membrane. The results of glutamate-induced neuronal excitatory injury cell model experiment for verification of active ingredients and mechanism of DZSM showed that there are five active ingredients, and among them, 4,5 caffeoylquinic acid (4,5-CQA) and scutellarin (SG) could simultaneously affect the GABAergic and glutamatergic synaptic metabolism as well as the related receptors, the NR2b subunit of NMDA and the α1 subunit of GABAA. The active ingredients of DZSM could regulate the over-expression of the NMDA receptor, enhance the expression of the GABAA receptor, resist glutamate-induced neuronal excitatory damage, and finally maintain the balance of excitatory and inhibitory synaptic metabolism dominated by glutamate and GABA. Furtherly, we compared the efficacy of DZSM, 4,5-CQA, SG and the synergistic effect of 4,5-CQA and SG, and the results showed that all the groups significantly improved cell viability compared with the model group (p < 0.001). The western blot results showed that DZSM, 4,5-CQA, SG and 4,5-CQA/SG co-administration groups could significantly regulate the expression of receptors (GABAA α1 and NR2b subunit of NMDA) and synaptic-related proteins, such as Sv2a, Syp, Slc17a7, bin1 and Prkca, respectively. These results proved DZSM and its active ingredients (4,5-CQA and SG) had the effect of regulating glutamatergic and GABAergic synapses. Finally, membrane potential FLIPR assay of 4,5-CQA and SG was used for GABRA1 activity test, and it was found that the two compounds could increase GABA-induced activation of GABRA1 receptor (GABA 10 µM) in a dose-dependent manner with EC50 value of 48.74 µM and 29.77 µM, respectively. Manual patch clamp method was used to record NMDA NR1/NR2B subtype currents, and scutellarin could cause around 10 % blockade at 10 µM (p＜0.05 compared with the control group). These studies provided definitive clues of the mechanism for the neuroprotective effect of DZSM for CCH treatment and the active compounds regulating glutamatergic and GABAergic synapses. Additionally, 4,5-CQA and SG might be potential drugs for the treatment of neurodegenerative disease related to CCH.

(-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) Quinic Acid Inhibits the Function of Myeloid-Derived Suppressor Cells to Enhance the Efficacy of Anti-PD1 against Colon Cancer.

PURPOSE: Immunotherapy in the clinic has demonstrated its potential to control cancer through disinhibiting the immune system, especially for immune checkpoint inhibitors such as anti-programmed cell death protein 1/anti-programmed death-ligand 1 (anti-PD1/anti-PD-L1). However, although these new immunotherapies have resulted in durable clinical responses in various cancers, multiple mechanisms of immune resistance and suppression exist in tumors. One significant barrier to efficacy of anti-PD1 against colon cancer may be the recruitment of myeloid-derived suppressor cells (MDSCs) into the tumor microenvironment. Here we demonstrated functional inhibition of G-MDSC with (-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid (QA), an inhibitor of PI3Kδ/γ, reshaped the tumor immune microenvironment and promoted cytotoxic T cell-mediated tumor regression, resultantly enhancing responses to anti-PD1 treatment in colon tumor model. METHODS: A syngeneic colon tumor mouse model was used to study the effects of QA on tumor immune microenvironment and its potential synergistic effects with anti-PD1 blockade. RESULTS: QA treatment inhibited G-MDSC function in the tumor tissue. Additionally, combination treatment induced CD8+ T lymphocyte-dependent tumor growth delay and prolonged survival time in colon cancer. CONCLUSIONS: Our results offered opportunities for new combination strategies using a selective small molecule PI3Kδ/γ inhibitor, to suppress MDSCs to enhance responses to immune checkpoint blockade in colon cancer.

In Vivo and In Vitro Anti-Arthritic Effects of Cardenolide-Rich and Caffeoylquinic Acid-Rich Fractions of Periploca forrestii.

Periploca forrestii Schltr. (P. forrestii) is a species used in Traditional Chinese Medicine (TCM) known as "Miao medicine", and has a long history of use in the treatment of rheumatism, rheumatoid arthritis (RA), and joint pain. The present study aimed to evaluate the anti-arthritis effects of the cardenolide-rich and caffeoylquinic acid-rich fractions (CDLFs and CQAFs) of P. forrestii in collagen-induced arthritic (CIA) rats, and defined the mechanisms of therapeutic action in MH7A cells treated with TNF-α. Serum rheumatoid factor (RF), TNF-α, IL-6, IL-1ß, PGE2, NO, SOD, and MDA were determined by ELISA or other commercially assay kits. Histopathological changes in ankle joint tissues were examined. The mRNA expressions of IL-1ß, IL-6, COX-2, and iNOS in MH7A cells were measured by qRT-PCR assays. In addition, the expressions of iNOS, COX-2, and p65 proteins, and the phosphorylation of IκBα, p38, ERK1/2, and JNK proteins in MH7A cells were analyzed by Western blot. The results showed that CDLF and CQAF could suppress the paw swelling in CIA rats at different doses (125 mg/kg, 250 mg/kg, and 500 mg/kg). Histopathological examination suggests that the CDLF and CQAF significantly relieved the damage of the structure of the ankle joint in CIA rats. In addition, serum RF, TNF-α, IL-6, IL-1ß, PGE2, NO, and MDA were decreased, along with increased activity of serum SOD. Furthermore, CDLF and CQAF downregulated the expressions of IL-1ß, IL-6, COX-2, iNOS, and p65, and inhibited the phosphorylation of IκBα, p38, ERK1/2, and JNK in MH7A cells treated with TNF-α. These findings demonstrated that both CDLF and CQAF exhibited anti-arthritic activity, which might be associated with their inhibitory effects on the NF-κB and MAPK signaling pathways.

Chlorogenic Compounds from Coffee Beans Exert Activity against Respiratory Viruses.

Chlorogenic acids are secondary metabolites in diverse plants. Some chlorogenic acids extracted from traditional medicinal plants are known for their healing properties, e.g., against viral infections. Also, green coffee beans are a rich source of chlorogenic acids, with 5-O-caffeoylquinic acid being the most abundant chlorogenic acid in coffee. We previously reported the synthesis of the regioisomers of lactones, bearing different substituents on the quinidic core. Here, 3,4-O-dicaffeoyl-1,5-γ-quinide and three dimethoxycinnamoyl-γ-quinides were investigated for in vitro antiviral activities against a panel of 14 human viruses. Whereas the dimethoxycinnamoyl-γ-quinides did not show any antiviral potency in cytopathogenic effect reduction assays, 3,4-O-dicaffeoyl-1,5-γ-quinide exerted mild antiviral activity against herpes simplex viruses, adenovirus, and influenza virus. Interestingly, when the compounds were evaluated against respiratory syncytial virus, a potent antiviral effect of 3,4-O-dicaffeoyl-1,5-γ-quinide was observed against both subtypes of respiratory syncytial virus, with EC50 values in the submicromolar range. Time-of-addition experiments revealed that this compound acts on an intracellular post-entry replication step. Our data show that 3,4-O-dicaffeoyl-1,5-γ-quinide is a relevant candidate for lead optimization and further mechanistic studies, and warrants clinical development as a potential anti-respiratory syncytial virus drug.

Chlorogenic Acid: Recent Advances on Its Dual Role as a Food Additive and a Nutraceutical against Metabolic Syndrome.

Chlorogenic acid (5-O-caffeoylquinic acid) is a phenolic compound from thehydroxycinnamic acid family. This polyphenol possesses many health-promoting properties, mostof them related to the treatment of metabolic syndrome, including anti-oxidant, anti-inflammatory,antilipidemic, antidiabetic, and antihypertensive activities. The first part of this review will discussthe role of chlorogenic acid as a nutraceutical for the prevention and treatment of metabolicsyndrome and associated disorders, including in vivo studies, clinical trials, and mechanisms ofaction. The second part of the review will be dealing with the role of chlorogenic acid as a foodadditive. Chlorogenic acid has shown antimicrobial activity against a wide range of organisms,including bacteria, yeasts, molds, viruses, and amoebas. These antimicrobial properties can beuseful for the food industry in its constant search for new and natural molecules for thepreservation of food products. In addition, chlorogenic acid has antioxidant activity, particularlyagainst lipid oxidation; protective properties against degradation of other bioactive compoundspresent in food, and prebiotic activity. The combination of these properties makes chlorogenic acidan excellent candidate for the formulation of dietary supplements and functional foods.

5-Caffeoylquinic acid decreases diet-induced obesity in rats by modulating PPARα and LXRα transcription.

BACKGROUND: Chlorogenic acids (CGAs) are widely distributed in plant material, including foods and beverages. 5-Caffeoylquinic acid (5-CQA) is the most studied CGA, but the mechanism of its hypolipidaemic effect remains unclear. This study aimed to determine the effect of 5-CQA on lipid metabolism in the liver of Sprague-Dawley rats fed a high-fat diet (HFD). RESULTS: 5-CQA suppressed HFD-induced increases in body weight and visceral fat-pad weight, serum lipid levels, and serum and hepatic free fatty acids in a dose-dependent manner. Real-time polymerase chain reaction revealed that 5-CQA altered the mRNA expression of the transcription factors peroxisome proliferator-activated receptor α (PPARα) and liver X receptor α (LXRα) and target genes involved in hepatic fatty acid uptake, ß-oxidation, fatty acid synthesis, and cholesterol synthesis. Moreover, hepatic tissue sections from HFD-fed rats showed many empty vacuoles, suggesting that liver cells were filled with more fat droplets. However, 5-CQA significantly ameliorated this effect. CONCLUSION: 5-CQA may improve lipid metabolism disorders by altering the expression of PPARα and LXRα, which are involved in multiple intracellular signalling pathways.

Caffeoylquinic Acid Mitigates Neuronal Loss and Cognitive Decline in 5XFAD Mice Without Reducing the Amyloid-ß Plaque Burden.

Background: Caffeoylquinic acid (CQA), which is abundant in coffee beans and Centella asiatica, reportedly improves cognitive function in Alzheimer's disease (AD) model mice, but its effects on neuroinflammation, neuronal loss, and the amyloid-ß (Aß) plaque burden have remained unclear. Objective: To assess the effects of a 16-week treatment with CQA on recognition memory, working memory, Aß levels, neuronal loss, neuroinflammation, and gene expression in the brains of 5XFAD mice, a commonly used mouse model of familial AD. Methods: 5XFAD mice at 7 weeks of age were fed a 0.8% CQA-containing diet for 4 months and then underwent novel object recognition (NOR) and Y-maze tests. The Aß levels and plaque burden were analyzed by enzyme-linked immunosorbent assay and immunofluorescent staining, respectively. Immunostaining of markers of mature neurons, synapses, and glial cells was analyzed. AmpliSeq transcriptome analysis and quantitative reverse-transcription-polymerase chain reaction were performed to assess the effect of CQA on gene expression levels in the cerebral cortex of the 5XFAD mice. Results: CQA treatment for 4 months improved recognition memory and ameliorated the reduction of mature neurons and synaptic function-related gene mRNAs. The Aß levels, plaque burden, and glial markers of neuroinflammation seemed unaffected. Conclusions: These findings suggest that CQA treatment mitigates neuronal loss and improves cognitive function without reducing Aß levels or neuroinflammation. Thus, CQA is a potential therapeutic compound for AD, improving cognitive function via as-yet unknown mechanisms independent of reductions in Aß or neuroinflammation.

Dietary intake and major food sources of polyphenols in a Spanish population at high cardiovascular risk: the PREDIMED study.

BACKGROUND AND AIMS: Epidemiological data have shown an inverse association between the consumption of polyphenol-rich foods and the risk of cardiovascular disease or overall mortality. A comprehensive estimation of individual polyphenol intake in nutritional cohorts is needed to gain a better understanding of this association. The aim of this study was to estimate the quantitative intake of polyphenols and the major dietary sources in the PREDIMED (PREvención con DIeta MEDiterránea) cohort using individual food consumption records. METHODS AND RESULTS: The PREDIMED study is a large, parallel-group, multicentre, randomised, controlled 5-year feeding trial aimed at assessing the effects of the Mediterranean diet on the primary prevention of cardiovascular disease. A total of 7200 participants, aged 55-80 years, completed a validated 1-year food frequency questionnaire (FFQ) at baseline. Polyphenol consumption was calculated by matching food consumption data from the FFQ with the recently developed Phenol-Explorer database on polyphenol content in foods. The mean total polyphenol intake was 820 ± 323 mg day⁻¹ (443 ± 218 mg day⁻¹ of flavonoids and 304 ± 156 mg day⁻¹ of phenolic acids). Hydroxycinnamic acids were the phenolic group with the highest consumption and 5-caffeoylquinic acid was the most abundantly ingested individual polyphenol. The consumption of olives and olive oil was a differentiating factor in the phenolic profile of this Spanish population compared with other countries. CONCLUSION: In Mediterranean countries, such as Spain, the main dietary source of polyphenols is coffee and fruits, but the most important differentiating factor with respect to other countries is the consumption of polyphenols from olives and olive oil.

Gene expression profiling reveals underlying molecular mechanism of hepatoprotective effect of Phyllanthus niruri on thioacetamide-induced hepatotoxicity in Sprague Dawley rats.

BACKGROUND: The liver plays an essential role in the body by regulating several important metabolic functions. Liver injury is associated with the distortion of these functions causing many health problems. Pharmaceutical drugs treat liver disorders but cause further damage to it. Hence, herbal drugs are used worldwide and are becoming increasingly popular. METHODS: The hepatoprotective activity of Phyllanthus niruri (PN) was evaluated against liver cirrhosis induced by thioacetamide (TAA) in male Sprague Dawley rats. Rats received intraperitoneal injections of thioacetamide (TAA, 200 mg/kg, b.w. three times weekly) for eight weeks. Daily treatments with plant extract (200 mg/kg) were administered orally for eight weeks. At the end of the study, hepatic damage was evaluated by monitoring transforming growth factor (TGFß), collagen α1 (Collα1), matrix metalloproteinase-2 (MMP2) and tissue inhibitor of matrix metalloproteinase-1 (TIMP1) gene expression by real-time PCR. Moreover, different chromatographic techniques including column chromatography, thin layer chromatography, and Ultra Performance Liquid Chromatography (UPLC) with Liquid Chromatography/Mass Spectrometry (LC/MS) were used to isolate the active constituents of the plant. RESULTS: The results revealed that treatment with PN significantly reduced the effect of thioacetamide toxicity and exhibited effective hepatoprotective activity. The mechanism of the hepatoprotective effect of PN is proposed to be by normalizing ROSs. Additionally, PN treatment regulated the expression of TGFß, Collα1, MMP2, and TIMP1 genes. In the active fraction of P. niruri, the isolated chemical constituents were 4-O-caffeoylquinic acid and quercetin 3-O-rhamnoside. CONCLUSIONS: The results of the present study indicate that PN ethanol extracts possess hepatoprotective activity that is most likely because of the isolated chemical constituents.

Ameliorative effects of Scutellaria Pinnatifida subsp. pichleri (Stapf) Rech.f. Extract in streptozotocin-induced diabetic rats: chemical composition, biochemical and histopathological evaluation.

BACKGROUNDS: Scutellaria Pinnatifida subsp. pichleri (Stapf) Rech.f. (SP) is used in folk medicine for the treatment of diabetes. The aim of the study was to determine the phenolic profile of SP extract (SPE) by LC-MS/MS and to investigate the antidiabetic, hepatoprotective and nephroprotective effects of SPE in streptozotosin (STZ)-induced diabetic rat model. METHODS: Forty-two rats were randomly divided into six groups (n = 7): Control (nondiabetic), diabetes mellitus (DM), DM + SP-100 (diabetic rats treated with SPE, 100 mg/kg/day), DM + SP-200 (diabetic rats treated with SPE, 200 mg/kg/day), DM + SP-400 (diabetic rats treated with SPE, 400 mg/kg/day) and DM + Gly-3 (diabetic rats treated with glibenclamide, 3 mg/kg/day). Live body weight, fasting blood glucose (FBG) level, antidiabetic, serum biochemical and lipid profile parameters, antioxidant defense system, malondyaldehyde (MDA) and histopathological examinations in liver, kidney and pancreas were evaluated. RESULTS: Apigenin, luteolin, quinic acid, cosmosiin and epigallocatechin were determined to be the major phenolic compounds in the SPE. Administration of the highest dose of SP extract (400 mg/kg) resulted in a significant reduction in FBG levels and glycosylated hemoglobin levels in STZ-induced diabetic rats, indicating an antihyperglycemic effect. SPE (200 and 400 mg/kg) and glibenclamide significantly improved MDA in liver and kidney tissues. In addition, SPE contributed to the struggle against STZ-induced oxidative stress by stimulating antioxidant defense systems. STZ induction negatively affected liver, kidney and pancreas tissues according to histopathological findings. Treatment with 400 mg/kg and glibenclamide attenuated these negative effects. CONCLUSIONS: In conclusion, the extract of the aerial part of Scutellaria pinnatifida subsp. pichleri has hepatoprotective, nephroprotective and insulin secretion stimulating effects against STZ-induced diabetes and its complications due to its antidiabetic and antioxidant phytochemicals such as apigenin, luteolin, quinic acid, cosmosiin and epigallocatechin.

Coffee polyphenols modulate whole-body substrate oxidation and suppress postprandial hyperglycaemia, hyperinsulinaemia and hyperlipidaemia.

Postprandial energy metabolism, including postprandial hyperglycaemia, hyperinsulinaemia and hyperlipidaemia, is related to the risk for developing obesity and CVD. In the present study, we examined the effects of polyphenols purified from coffee (coffee polyphenols (CPP)) on postprandial carbohydrate and lipid metabolism, and whole-body substrate oxidation in C57BL/6J mice. In mice that co-ingested CPP with a lipid-carbohydrate (sucrose or starch)-mixed emulsion, the respiratory quotient determined by indirect calorimetry was significantly lower than that in control mice, whereas there was no difference in VO2 (energy expenditure), indicating that CPP modulates postprandial energy partitioning. CPP also suppressed postprandial increases in plasma glucose, insulin, glucose-dependent insulinotropic polypeptide and TAG levels. Inhibition experiments on digestive enzymes revealed that CPP inhibits maltase and sucrase, and, to a lesser extent, pancreatic lipase in a concentration-dependent manner. Among the nine kinds of polyphenols (caffeoyl quinic acids (CQA), di-CQA, feruloyl quinic acids (FQA)) contained in CPP, di-CQA showed more potent inhibitory activity than CQA or FQA on these digestive enzymes, suggesting a predominant role of di-CQA in the regulation of postprandial energy metabolism. These results suggest that CPP modulates whole-body substrate oxidation by suppressing postprandial hyperglycaemia and hyperinsulinaemia, and these effects are mediated by inhibiting digestive enzymes.

Anti-Inflammatory Effect of 4,5-Dicaffeoylquinic Acid on RAW264.7 Cells and a Rat Model of Inflammation.

Anti-inflammatory agents that are safer and more effective than the currently used non-steroidal anti-inflammatory drugs are urgently needed. The dicaffeoylquinic acid (diCQA) isomer 4,5-diCQA exhibits antioxidant activity and various other health-promoting benefits; however, its anti-inflammatory properties require further investigation. This study was conducted to evaluate the anti-inflammatory properties of 4,5-diCQA in vitro and in vivo using RAW264.7 cells and a carrageenan-induced inflammation model, respectively. In RAW264.7 cells, 4,5-diCQA pretreatment significantly inhibited lipopolysaccharide-induced expression of nitric oxide, prostaglandin E2, nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, interleukin-1ß, and interleukin-6, without inducing cytotoxicity. The inhibitory effects of 4,5-diCQA were mediated by the suppression of nuclear factor-κB nuclear translocation and mitogen-activated protein kinase (MAPK) phosphorylation. Oral administration of 4,5-diCQA at doses of 5, 10, and 20 mg/kg of the body weight suppressed carrageenan-induced edema and the expression of nitric oxide synthase, cyclooxygenase-2, and tumor necrosis factor-α in a dose-dependent manner. Collectively, our results suggest that 4,5-diCQA exerts anti-inflammatory effects by suppressing activation of the nuclear factor-κB and MAPK pathways in vitro and reducing carrageenan-induced edema in vivo. Therefore, 4,5-diCQA shows potential as a natural alternative to non-steroidal anti-inflammatory drugs.

Anti-ulcerogenic effect and HPLC analysis of the caffeoylquinic acid-rich extract from Ligularia stenocephala.

The leaves of three Ligularia species belonging to the family Compositae, Ligularia stenocephala, L. fischeri, and L. fischeri var. spiciformis, were qualitatively and quantitatively analyzed on the caffeoylquinic acids by HPLC and subjected to peroxynitrite-scavenging assay. The IC(50) of the MeOH extract of L. stenocephala was 1.62+/-0.03 mug/ml and the major caffeoylquinic acids of L. stenocephala were 5-O-caffeoylquinic acid, 3,5-di-O-caffeoyl-muco-quinic acid, and 3,5-di-O-caffeoylquinic acid. The compositions of caffeoylquinic acids were different for the three plants. Since percentage of total caffeoylquinic acids of the extract was highest (42.20% of the MeOH extract and 94.52% of the BuOH extract) in L. stenocephala and potent in peroxynitrite-scavenging assay, the extracts of L. stenocephala were chosen to perform in vivo anti-ulcerogenic activity. Treatment of mice with the MeOH- and BuOH extracts decreased the diameter of gastric lesions caused by HCl/ethanol- and indomethacin/bethanechol and decreased the volume of gastric juice, suggesting that caffeoylquinic acids have anti-ulcerogenic activity. These results suggest that the leaves of Ligularia species may help prevent or treat gastric ulcers.

3,5-Di-O-caffeoyl-epi-quinic acid from the leaves and stems of Erigeron annuus inhibits protein glycation, aldose reductase, and cataractogenesis.

In our ongoing project directed toward the discovery of novel treatments for diabetic complications from herbal medicines, sixteen compounds including three caffeoylquinic acids and four flavonoids were isolated from an EtOAc-soluble extract of the stems and leaves of Erigeron annuus. All the isolates were evaluated in vitro for inhibitory activity on the formation of advanced glycation end products (AGEs) and rat lens aldose reductase (RLAR). Of these, 3,5-di-O-caffeoyl-epi-quinic acid (3) exhibited the most potent inhibitory activity in both the AGEs and aldose reductase (AR) assays. Compound 3 markedly reduced AGEs-bovin serum albumin (BSA) cross-linking in a dose-dependent manner. Furthermore, opacity of lenses was significantly prevented when they were treated with 3 in an ex vivo experiment.

Caffeoylquinic Acids in Centella asiatica Reverse Cognitive Deficits in Male 5XFAD Alzheimer's Disease Model Mice.

Centella asiatica (CA) is an edible plant and a popular botanical dietary supplement. It is reputed, in Ayurveda, to mitigate age-related cognitive decline. There is a considerable body of preclinical literature supporting CA's ability to improve learning and memory. This study evaluated the contribution of CA's triterpenes (TT), widely considered its active compounds, and caffeoylquinic acids (CQA) to the cognitive effects of CA water extract (CAW) in 5XFAD mice, a model of Alzheimer's disease. 5XFAD mice were fed a control diet alone, or one containing 1% CAW or compound groups (TT, CQA, or TT + CQA) equivalent to their content in 1% CAW. Wild-type (WT) littermates received the control diet. Conditioned fear response (CFR) was evaluated after 4.5 weeks. Female 5XFAD controls showed no deficit in CFR compared to WT females, nor any effects from treatment. In males, CFR of 5XFAD controls was attenuated compared to WT littermates (p = 0.005). 5XFAD males receiving CQA or TT + CQA had significantly improved CFR (p < 0.05) compared to 5XFAD male controls. CFR did not differ between 5XFAD males receiving treatment diets and WT males. These data confirm a role for CQA in CAW's cognitive effects.

Quinic acid derivatives from Saussurea triangulata attenuates glutamate-induced neurotoxicity in primary cultured rat cortical cells.

The leaves of Saussurea triangulata (Compositae) have been eaten with rice as a wrapping vegetable for preventing neuro-aging. However, the components responsible for the neuroprotective effects of S. triangulata still remain unidentified. In the process of investigating the neuroprotective activity of S. triangulata, we found that a methanol extract of S. triangulata exhibited significant protection against glutamate-induced toxicity in primary cultured rat cortical cells. Three quinic acid derivatives were isolated from the n-BuOH fraction of S. triangulata. Among these three quinic acid derivatives, methyl 5-caffeoylquinic acid (3) exhibited significant neuroprotective activities against glutamate-induced toxicity exhibiting cell viability of about 50%, at concentrations ranging from 0.1 microM to 10 microM. Therefore, the neuroprotective effect of S. triangulata might be due to the inhibition of glutamate-induced toxicity by the quinic acid derivatives from S. triangulata.

Chemical investigation of Hyptis suaveolens seed, a potential antihyperuricemic nutraceutical, with assistance of HPLC-SPE-NMR.

The seed of Hyptis suaveolens, commonly known as wild flour ball (san fen yuan) in Taiwan, serves as a main refreshing drink substance in several regions. This study investigated firstly its secondary metabolites, leading to the isolation of five major caffeoylquinic acid derivatives (1-5) from the ethanol extract. In addition, ten minors, including three caffeoylquinic acid derivatives (12-14), were characterized via assistance of HPLC-SPE-NMR. Of these isolates, sodium 4,5-dicaffeoylquinate (2) and methyl 3,5-dicaffeoylquinate (4) showed moderate inhibitory activity against xanthine oxidase with the respective IC50 values of 69.4 µM and 92.1 µM (c.f. allopurinol IC50 28.4 µM). Quantitative HPLC analysis of the EtOH extract indicates the content of sodium 3,5-dicaffeoylquinate (1) and sodium 4,5-dicaffeoylquinate (2) to be 0.1% and 0.08% (w/w, dry seed), respectively. This study not only discloses the bioactive constituents, but also demonstrates the potential of H. suaveolens seed as an antihyperuricemic nutraceutical.

Hydroxyhydroquinone interferes with the chlorogenic acid-induced restoration of endothelial function in spontaneously hypertensive rats.

BACKGROUND: Coffee is a rich source of antioxidative polyphenols, but epidemiological studies and interventional trials have failed to demonstrate any clear beneficial effects of coffee consumption on hypertension. The interaction between hydroxyhydroquinone (HHQ) and 5-caffeoylquinic acid (CQA) was examined, in an attempt to understand the controversial effects of coffee on hypertension. METHODS: Male Wistar Kyoto (WKY) rats or spontaneously hypertensive rats (SHRs, 14 weeks old) were divided into the following four groups; those on a control diet, 0.005% HHQ diet, 0.5% CQA diet, and HHQ plus CQA diet. The rats were fed the above diets for 8 weeks, and the tail arterial blood pressure was monitored in conscious rats at 2-week intervals. Urinary nitric oxide (NO) metabolites and hydrogen peroxide (H(2)O(2)) excretion were measured 8 weeks after the start of the experiment. Endothelium-dependent and -independent vasorelaxant responses and immunohistochemical staining for nitrotyrosine were examined in aortas. RESULTS: HHQ inhibited the CQA-induced improvement in hypertension, urinary NO metabolites or H(2)O(2) excretion, endothelial dysfunction, and nitrotyrosine deposits in aortas in SHR. However, the administration of HHQ alone had little effect on either strain. CONCLUSIONS: Based on the content ratio of HHQ and chlorogenic acids in coffee, HHQ interfered with the CQA-induced improvement in blood pressure and endothelial function in SHR. The results explain, at least in part, the conflicting action of coffee drinking on hypertension and vascular reactivity.

Quinic acid inhibits vascular inflammation in TNF-α-stimulated vascular smooth muscle cells.

Atherosclerosis is a chronic inflammatory disease, and the increased expression of adhesion molecules on vascular smooth muscle cells contributes to the progression of vascular disease. Quinic acid (QA) has been shown to possess radioprotection, anti-neuroinflammatory, and anti-oxidant activities; however, an anti-vascular inflammatory effect has not been reported. This study investigated the effect of QA on the expression of vascular cell adhesion molecule-1 (VCAM-1) stimulated by TNF-α in MOVAS cells. Pre-incubation of MOVAS cells, the mouse vascular smooth muscle cell line for 2h with QA (0.1, 1 and 10 µg/mL) dose-dependently inhibits TNF-α-induced mRNA and protein expression of VCAM-1 and monocyte adhesion. QA inhibits TNF-α-stimulated phosphorylation of MAP kinase and NK-κB activation. Our results indicate that QA inhibits the TNF-α-stimulated induction of VCAM-1 in VSMC by inhibiting the MAP kinase and NF-κB signaling pathways and the adhesion capacity of VSMC, which may explain the ability of QA to inhibit vascular inflammation such as atherosclerosis.