Protective effects of chlorogenic acid against cyclophosphamide induced liver injury in mice

We investigated possible protective effects of chlorogenic acid (CGA) against cyclophosphamide (CP) induced hepatic injury in mice. We measured aminotransferase alanine transaminase (ALT) and aspartate transaminase (AST) levels in the serum. We assayed catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in hepatic tissue. We assessed expression of nuclear transcription factor 2 (Nrf2) and Kelch sample related protein-1 (keap1) proteins in hepatic tissues using immunohistochemistry. The relative mRNA expression levels of heme oxygenase-1 (HO-1), NADH quinone oxidoreductase 1 (NQO1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Hematoxylin & eosin staining was used to assess liver histopathology. We found that administration of CGA prior to induction of injury by CP decreased serum ALT, AST and MDA expressions in hepatic tissue, while CAT, SOD, GSH and GSH-Px concentrations were increased. We found that hepatocytes of animals administered CGA gradually returned to normal morphology. CGA increased the protein expression of Nrf2 in murine hepatic tissue. Administration of CGA up-regulated mRNA expression levels of HO-1, NQO1, TNF-α and IL-6 in hepatic tissue. CGA exhibited a marked protective effect on CP induced liver injury in mice.

Exogenous chlorogenic acid inhibits quality deterioration in fresh-cut potato slices

Fresh-cut potatoes are prone to surface browning and physiological degradation. Chlorogenic acid (CGA), a natural phenolic antioxidant, has demonstrated preservative properties in various postharvest products. However, the underlying mechanisms of its application on maintaining quality remain unclear. Therefore, the effect of exogenous CGA treatment on quality deterioration of potato slices and the mechanisms involved were investigated. Results revealed CGA treatment retarded the browning coloration, suppressed microbial growth and inhibited the declines in starch, and ascorbic acid contents in potato slices. Meanwhile, the treatment activated the phenylpropanoid pathway but decreased the activities of phenolic decomposition-related enzymes such as polyphenol oxidase (PPO) and tyrosinase and downregulated StPPO expression. Moreover, the treated slices exhibited reduced accumulation of reactive oxygen species and increased activity of antioxidant enzymes. Additionally, they displayed enhanced 2,2-diphenyl-1-picrylhydrazyl radicals scavenging capacity and higher ATP levels. Therefore, these findings indicated that CGA treatment was effective for quality maintenance and antioxidant capacity enhancement in fresh-cut potatoes, thereby providing potential strategies for the preservation and processing of fresh-cut produce.

Chlorogenic acid prevents ovariectomized-induced bone loss by facilitating osteoblast functions and suppressing osteoclast formation

Osteoporosis is a usual bone disease in aging populations, principally in postmenopausal women. Anti-resorptive and anabolic drugs have been applied to prevent and cure osteoporosis and are associated to a different of adverse effects. Du-Zhong is usually applied in Traditional Chinese Medicine to strengthen bone, regulate bone metabolism, and treat osteoporosis. Chlorogenic acid is a major polyphenol in Du-Zhong. In the current study, chlorogenic acid was found to enhance osteoblast proliferation and differentiation. Chlorogenic acid also inhibits the RANKL-induced osteoclastogenesis. Notably, ovariectomy significantly decreased bone volume and mechanical properties in the ovariectomized (OVX) rats. Administration of chlorogenic acid antagonized OVX-induced bone loss. Taken together, chlorogenic acid seems to be a hopeful molecule for the development of novel anti-osteoporosis treatment.

Quantitative Phosphoproteomics Analysis Reveals the Protective Mechanism of Chlorogenic Acid on Immunologically Stressed Broiler Meat Quality

Modern poultry production is stressful for the birds, and this stress is recognized as a major cause of inferior meat quality. Chlorogenic acid (CGA), a plant phenolic acid, has excellent antioxidant and anti-inflammatory properties. The antioxidant capacity and phosphoproteomics of immunologically stressed broiler breast muscle were assessed to elucidate the mechanism of the beneficial effects of CGA on meat quality. Dietary CGA decreased drip and cooking loss, postmortem pH and antioxidant capacity of breast muscle from stressed broilers, and increased MyHC-I mRNA levels. Quantitative phosphoproteomics revealed that CGA supplementation downregulated the phosphorylation of myofibrillar proteins, glycolytic enzymes, and endoplasmic reticulum proteins involved in homeostasis, which contributed to improving the meat quality of broilers. Moreover, 14 phosphorylation sites (e.g., P13538-Ser1236 and F1NN63-Ser117) in 13 phosphoproteins were identified as key regulators of processes related to broiler meat quality. Together, these findings provide novel regulatory targets and nutritional strategies for improving the stressed broiler meat quality.

Hesperidin and chlorogenic acid mitigate arsenic-induced oxidative stress via redox regulation, photosystems-related gene expression, and antioxidant efficiency in the chloroplasts of Zea mays

The ubiquitous metalloid arsenic (As), which is not essential, can be found extensively in the soil and subterranean water of numerous nations, raising substantial apprehensions due to its impact on both agricultural productivity and sustainability. Plants exposed to As often display morphological, physiological, and growth-related abnormalities, collectively leading to reduced productivity. Polyphenols, operating as secondary messengers within the intricate signaling networks of plants, assume integral functions in the acquisition of resistance to diverse environmental stressors, including but not limited to drought, salinity, and exposure to heavy metals. The pivotal roles played by polyphenols in these adaptive processes underscore their profound significance in plant biology. This study aims to elucidate the impact of hesperidin (HP) and chlorogenic acid (CA), recognized as potent bioactive compounds, on maize plants exposed to As. To achieve this objective, the study examined the physiological and biochemical impacts, including growth parameters, photosynthesis, and chloroplastic antioxidants, of HP (100 μM) and CA (50 μM) on Zea mays plants exposed to arsenate stress (AsV, 100 μM - Na2HAsO4⋅7H2O). As toxicity led to reductions in fresh weight (FW) and dry weight (DW) by 33% and 26%, respectively. However, the application of As+HP and As + CA increased FW by 22% and 40% and DW by 14% and 17%, respectively, alleviating the effects of As stress. As toxicity resulted in the up-regulation of PSII genes (psbA and psbD) and PSI genes (psaA and psaB), indicating a potential response to the re-formation of degraded regions, likely driven by the heightened demand for photosynthesis. Exogenous HP or/and CA treatments effectively counteracted the adverse effects of As toxicity on the photochemical quantum efficiency of PSII (Fv/Fm). H2O2 content showed a 23% increase under As stress, and this increase was evident in guard cells when examining confocal microscopy images. In the presence of As toxicity, the chloroplastic antioxidant capacity can exhibit varying trends, with either a decrease or increase observed. After the application of CA and/or HP, a significant increase was observed in the activity of GR, APX, GST, and GPX enzymes, resulting in decreased levels of H2O2 and MDA. Additionally, the enhanced functions of MDHAR and DHAR have modulated the redox status of ascorbic acid (AsA) and glutathione (GSH). The HP or CA-mediated elevated levels of AsA and GSH content further contributed to the preservation of redox homeostasis in chloroplasts facing stress induced by As. In summary, the inclusion of HP and CA in the growth medium sustained plant performance in the presence of As toxicity by regulating physiological and biochemical characteristics, chloroplastic antioxidant enzymes, the AsA-GSH cycle and photosynthesis processes, thereby demonstrating their significant potential to confer resistance to maize through the mitigation of As-induced oxidative damage and the safeguarding of photosynthetic mechanisms.

High-Level Biosynthesis of Chlorogenic Acid from Mixed Carbon Sources of Xylose and Glucose through a Rationally Refactored Pathway Network

Chlorogenic acid (CGA) has incredible potential for various pharmaceutical, nutraceutical, and agricultural applications. However, the traditional extraction approach from plants is time-consuming, further limiting its production. Herein, we design and construct the de novo biosynthesis pathway of CGA using modular coculture engineering in Escherichia coli, which is composed of MG09 and BD07 strains. To accomplish this, the phenylalanine-deficient MG09 strain was engineered to utilize xylose preferentially and to overproduce precursor caffeic acid, while the tyrosine-deficient BD07 strain was constructed to consume glucose exclusively to enhance another precursor quinic acid availability for the biosynthesis of CGA. Further pathway modularization and balancing in the context of syntrophic cocultures resulted in additional production improvement. The coculture strategy avoids metabolic flux competition in the biosynthesis of two CGA precursors, caffeic acid and quinic acid, and allows for production improvement by balancing module proportions. Finally, the optimized coculture based on the aforementioned efforts produced 131.31 ± 7.89 mg/L CGA. Overall, the modular coculture engineering strategy in this study provides a reference for constructing microbial cell factories that can efficiently biomanufacture complex natural products.

Chlorogenic acid ameliorates the heat stress-induced impairment of porcine Sertoli cells by suppressing oxidative stress and apoptosis

Sertoli cells are an important type of somatic cell in the testis that are in direct contact with spermatogonia in vivo and play an important role in the process of spermatogenesis. Chlorogenic acid (CGA) plays a pivotal role in the regulation of the mammalian cell heat stress response. For example, CGA treatment protects porcine oocytes from heat stress-induced apoptosis and prevents reduced embryo quality. However, the role of CGA treatment in protecting porcine testicular Sertoli cells against heat-induced damage has rarely been studied. This study aimed to identify the protective effects of CGA on oxidative stress and apoptosis in Sertoli cells under heat stress. The present results demonstrated that the addition of CGA significantly inhibited the accumulation of reactive oxygen species (ROS) and apoptosis in Sertoli cells induced by heat stress and decreased the expression of CASP3 protein and the BAX/BCL-2 protein ratio. CGA pretreatment also prevented the heat stress-induced reductions in the mitochondrial membrane potential, PCNA protein expression, and SOD and CAT activities. Moreover, CGA treatment reversed S phase cell cycle arrest and increased the HSP70 protein expression levels. Overall, these results suggest that oxidative damage participates in the inhibition of the proliferation of Sertoli cells and the increase in their apoptosis induced by heat stress, and the protective effects of CGA treatment on Sertoli cells under heat stress provide a theoretical basis for preventing heat stress injury in animals.

Chlorogenic Acid Attenuates Hepatic Steatosis by Suppressing ZFP30

Nonalcoholic fatty liver disease (NAFLD) has become a major global health problem with no approved pharmacological treatment for this disease. Thus, it is urgent to develop effective therapeutic targets for clinical intervention. Here, we show for the first time that ZFP30, a member of the KRAB-ZFP family, is significantly increased in NAFLD models. ZFP30 silencing ameliorates free fatty acid (FFA)-induced lipid accumulation; in contrast, the ZFP30 overexpression exacerbates the triglyceride accumulation and steatosis in hepatocytes. Further investigation revealed that the effects of ZFP30 on hepatic lipid accumulation were mainly attributed to the PPARα downregulation in the NAFLD model. Mechanistically, ZFP30 directly binded to the promoter of PPARα and recruited KAP1 to suppress its transcription. Moreover, chlorogenic acid (CGA) reversed the upregulation of ZFP30 in NAFLD, promoting the PPARα expression, resulting in enhanced fatty acid oxidation and alleviated hepatic steatosis. Collectively, our study indicates ZFP30 as a potential target for NAFLD treatment.

Modulation of apoptosis and Inflammasome activation in chondrocytes: co-regulatory role of Chlorogenic acid

BACKGROUND

The B-cell lymphoma 2 (Bcl-2) protein regulates programmed cell death throughout the disease conditions by upholding apoptotic pathways. However, the mechanism by which it's expressed in chondrocytes still needs to be studied in chondrocyte-related disorders. Additionally, exploring the potential therapeutic role of Chlorogenic acid (CGA) in confluence with Bcl-2 modulation is of significant interest.

METHODS

In vivo and in vitro studies were performed according to our previous methodologies. The chondrocytes were cultured in specific growth media under standard conditions after expression verification of different microRNAs through high-throughput sequencing and verification of Bcl-2 involvement in tibial growth plates. The effect of Bcl-2 expression was investigated by transfecting chondrocytes with miR-460a, siRNA, and their negative controls alone or in combination with CGA. The RNA was extracted and subjected to a reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Western blot analysis and immunofluorescence assays were performed to visualize the intracellular localization of Bcl-2 and associated proteins related to apoptotic and inflammasome pathways. Moreover, apoptosis through flow cytometry was also performed to understand the modulation of concerning pathways.

RESULTS

The suppression of Bcl-2 induced higher apoptosis and mitochondrial dysfunction, leading to IL-1β maturation and affecting the inflammasome during chondrocyte proliferation. Conversely, overexpression attenuated the activation, as evidenced by reduced caspase activity and IL-1β maturation. In parallel, CGA successfully reduced siRNA-induced apoptosis by decreasing Cytochrome C (Cyto C) release from the mitochondria to the cytoplasm, which in turn decreased Caspase-3 and Caspase-7 cleavage with Bcl-2-associated X protein (Bax). Furthermore, siBcl-2 transfection and CGA therapy increased chondrocyte proliferation and survival. The CGA also showed a promising approach to maintaining chondrocyte viability by inhibiting siRNA-induced apoptosis.

CONCLUSIONS

Targeting Bcl-2-mediated regulation might be a possible treatment for chondrocyte-related conditions. Moreover, these results add knowledge of the complicated processes underlying chondrocyte function and the pathophysiology of related diseases, highlighting the significance of target specific therapies. Video Abstract.

Integrated metabolic profiling and transcriptome analysis of Lonicera japonica flowers for chlorogenic acid, luteolin and endogenous hormone syntheses

The active ingredients of many medicinal plants are the secondary metabolites associated with the growth period. Lonicera japonica Thunb. is an important traditional Chinese medicine, and the flower development stage is an important factor that influences the quality of medicinal ingredients. In this study, transcriptomics and metabolomics were performed to reveal the regulatory mechanism of secondary metabolites during flowering of L. japonica. The results showed that the content of chlorogenic acid (CGA) and luteolin gradually decreased from green bud stage (Sa) to white flower stage (Sc), especially from white flower bud stage (Sb) to Sc. Most of the genes encoding the crucial rate-limiting enzymes, including PAL, C4H, HCT, C3'H, F3'H and FNSII, were down-regulated in three comparisons. Correlation analysis identified some members of the MYB, AP2/ERF, bHLH and NAC transcription factor families that are closely related to CGA and luteolin biosynthesis. Furthermore, differentially expressed genes (DEGs) involved in hormone biosynthesis, signalling pathways and flowering process were analysed in three flower developmental stage.

The structure of a Lactobacillus helveticus chlorogenic acid esterase and the dynamics of its insertion domain provide insights into substrate binding

Chlorogenic acid esterases (ChlEs) are a useful class of enzymes that hydrolyze chlorogenic acid (CGA) into caffeic and quinic acids. ChlEs can break down CGA in foods to improve their sensory properties and release caffeic acid in the digestive system to improve the absorption of bioactive compounds. This work presents the structure, molecular dynamics, and biochemical characterization of a ChlE from Lactobacillus helveticus (Lh). Molecular dynamics simulations suggest that substrate access to the active site of LhChlE is modulated by two hairpin loops above the active site. Docking simulations and mutational analysis suggest that two residues within the loops, Gln145 and Lys164 , are important for CGA binding. Lys164 provides a slight substrate preference for CGA, whereas Gln145 is required for efficient turnover. This work is the first to examine the dynamics of a bacterial ChlE and provides insights on substrate binding preference and turnover in this type of enzyme.

EGR1 is crucial for the chlorogenic acid-provided promotion on liver regeneration and repair after APAP-induced liver injury

Improper use of acetaminophen (APAP) will induce acute liver failure. This study is designed to investigate whether early growth response-1 (EGR1) participated in the promotion on liver repair and regeneration after APAP-induced hepatotoxicity provided by natural compound chlorogenic acid (CGA). APAP induced the nuclear accumulation of EGR1 in hepatocytes regulated by extracellular-regulated protein kinase (ERK)1/2. In Egr1 knockout (KO) mice, the liver damage caused by APAP (300 mg/kg) was more severe than in wild-type (WT) mice. Results of chromatin immunoprecipitation and sequencing (ChIP-Seq) manifested that EGR1 could bind to the promoter region in Becn1, Ccnd1, and Sqstm1 (p62) or the catalytic/modify subunit of glutamate-cysteine ligase (Gclc/Gclm). Autophagy formation and APAP-cysteine adduct (APAP-CYS) clearance were decreased in Egr1 KO mice administered with APAP. The EGR1 deletion reduced hepatic cyclin D1 expression at 6, 12, or 18 h post APAP administration. Meanwhile, the EGR1 deletion also decreased hepatic p62, Gclc and Gclm expression, GCL enzymatic activity, and glutathione (GSH) content and decreased nuclear factor erythroid 2-related factor 2 (Nrf2) activation and thus aggravated oxidative liver injury induced by APAP. CGA increased EGR1 nuclear accumulation; enhanced hepatic Ccnd1, p62, Gclc, and Gclm expression; and accelerated the liver regeneration and repair in APAP-intoxicated mice. In conclusion, EGR1 deficiency aggravated liver injury and obviously delayed liver regeneration post APAP-induced hepatotoxicity through inhibiting autophagy, enhancing liver oxidative injury, and retarding cell cycle progression, but CGA promoted the liver regeneration and repair in APAP-intoxicated mice via inducing EGR1 transcriptional activation.

Effects Of Exercise Training And Chlorogenic Acid Supplementation On Hepatic Lipid Metabolism In Prediabetes Mice

BACKGRUOUND

Since prediabetes is a risk factor for metabolic syndromes, it is important to promote a healthy lifestyle to prevent prediabetes. This study aimed to determine the effects of green coffee (GC), chlorogenic acid (CGA) intake, and exercise training (EX) on hepatic lipid metabolism in prediabetes male C57BL/6 mice.

METHODS

Forty-nine mice were randomly divided into two groups feeding with a normal diet (n=7) or a high-fat diet (HFD, n=42) for 12 weeks. Then, HFD mice were further divided into six groups (n=7/group): control (pre-D), GC, CGA, EX, GC+EX, and CGA+EX. After additional 10 weeks under the same diet, plasma, and liver samples were obtained.

RESULTS

HFD-induced prediabetes conditions with increases in body weight, glucose, insulin, insulin resistance, and lipid profiles were alleviated in all treatment groups. Acsl3, a candidate gene identified through an in silico approach, was lowered in the pre-D group, while treatments partly restored it. HFD induced adverse alterations of de novo lipogenesis- and β oxidation-associated molecules in the liver. However, GC and CGA supplementation and EX reversed or ameliorated these changes. In most cases, GC or CGA supplementation combined with EX has no synergistic effect and the GC group had similar results to the CGA group.

CONCLUSION

These findings suggest that regular exercise is an effective non-therapeutic approach for prediabetes, and CGA supplementation could be an alternative to partially mimic the beneficial effects of exercise on prediabetes.

Chlorogenic Acid from Burdock Roots Ameliorates Oleic Acid-Induced Steatosis in HepG2 Cells through AMPK/ACC/CPT-1 Pathway

Hepatic steatosis can cause liver dysfunction and cell injury, on which natural functional factors are expected to be an effective approach for long-term intervention. However, the cellular molecular mechanisms are unclear. Chlorogenic acid is a phenolic compound, which can regulate lipid metabolism and is abundant in burdock root. The aim of this study was to investigate the potential molecular mechanism of the effect of chlorogenic acid from burdock root (ACQA) on steatosis in HepG2 cells. In this study, we found that ACQA reduced the number of lipid droplets and lipid levels in oleic acid-treated HepG2 cells. Molecular mechanistic results showed that ACQA enhanced CPT-1 expression by activating AMPK-related signaling pathways, and the concentrations of Ca2+ and cAMP were increased with the intervention of ACQA. In addition, ACQA enhanced the β-oxidation of fatty acids, reduced alanine transaminase and aspartate transaminase, and inhibited apoptosis in oleic acid-treated HepG2 cells. Our studies elucidate a novel mechanism that ACQA enhances the β-oxidation of fatty acids through the AMPK/ACC/CPT-1 pathway to protect against steatosis in HepG2 cells, which provides insight into its molecular mechanism as well as intervention strategies for chlorogenic acid against fatty liver diseases.

Chlorogenic Acid Modulates Autophagy by Inhibiting the Activity of ALKBH5 Demethylase, Thereby Ameliorating Hepatic Steatosis

Chlorogenic acid (CGA) is a naturally occurring plant component with the purpose of alleviating hepatic lipid deposition biological activities. However, the molecular mechanism behind this ability of CGA remains unelucidated. Consequently, we investigated the effect of CGA on hepatic lipid accumulation and elucidated its underlying mechanism. Our study used a high-fat diet (HFD)-induced mouse nonalcoholic fatty liver disease (NAFLD) model in mice to investigate the impact of CGA on hepatic lipid accumulation. The results revealed that the oral administration of CGA can ameliorate HFD-induced hepatic lipid deposition, reduce the NAFLD activity score (NAS), enhance liver autophagy, mitigate liver cell structural damage, and inhibit the MAPK/ERK signaling pathway. Meanwhile, CGA treatment increased the LC3B:LC3B ratio and decreased P62 expression. Cell experiments demonstrated that autophagy contributes to the ability of CGA to alleviate lipid deposition. Further analysis revealed that CGA specifically binds to ALKBH5 and inhibits its m6A methylase activity. The inhibition of ALKBH5 activity significantly reduces AXL mRNA stability in liver cells. The AXL downregulation resulted in suppressing ERK signaling pathway activation. Overall, this study demonstrates that CGA can alleviate hepatic steatosis by regulating autophagy through the inhibition of ALKBH5 activity inhibition.

Efficient Production of Chlorogenic Acid in Escherichia coli Via Modular Pathway and Cofactor Engineering

Chlorogenic acid is a natural phenolic compound widely used in the food and daily chemical industries. Compared to plant extraction, microbial cell factories provide a green and sustainable production method for the production of chlorogenic acid. However, complex metabolic flux distribution and potential byproducts limited the biosynthesis of chlorogenic acid in microorganisms. A de novo biosynthesis pathway for chlorogenic acid was constructed in Escherichia coli via modular engineering. Increasing the shikimate pathway flux greatly promoted chlorogenic acid production, and the influence of pyruvate metabolism on chlorogenic acid synthesis was also explored. The supply of cofactors for the key enzymes quinate/shikimate 5-dehydrogenase (YdiB) and 4-hydroxyphenylacetate 3-monooxygenase (HpaBC) was enhanced by a cofactor regeneration system. Furthermore, mutants of YdiB were verified for chlorogenic acid production in vivo. Chlorogenic acid browning occurred when the buffer pH of the buffer exceeded 6.0, but two-stage pH control achieved a chlorogenic acid titer of 2789.2 mg/L in a 5 L fermenter, the highest reported to date. This study provided a strategy for the efficient production of chlorogenic acid from simple carbon sources.

Combinatorial transcriptomics and metabolomics analysis reveals the effects of the harvesting stages on the accumulation of phenylpropanoid metabolites in Lonicera japonica

The flower buds of Lonicera japonica are widely used for its high medicinal value. It is reported that the accumulation of phenylpropanoids in the buds of L. japonica is affected by the stage at which it is harvested. However, the changes of active components and the underlying mechanisms in flower buds at different harvesting stages have not been reported. Integrative analyses of transcriptomics and metabolomics was used to explore the underlying mechanism of harvesting stages (green bud, GB; and white bud, WB) on the phenylpropanoids metabolites accumulation in L. japonica . The result showed that 3735 differentially expressed genes were identified, and the genes related to glycolysis/gluconeogenesis and phenylalanine biosynthesis pathway were significantly upregulated in GB stage. A total of 510 differential metabolites were identified in GB stage. Among them, 14 phenylpropanoids were changed during the GB and WB, seven of which increased in GB, including caffeic acid, sauchinone, coniferin, secoisolariciresinol diglucoside, scopolin, methyl cinnamate, chlorogenic acid, 7-hydroxycoumarin, while others such as sibiricose A6, coumarin, eleutheroside E decreased. Further correlation analysis showed that the unigenes for CSE, CAD, bg1, ADH, ALDH, DLAT and ENO significantly correlated with the 10 phenylpropanoid. The above results would provide basic data for the selection of harvesting stages in the production of L. japonica .

Chlorogenic acid improves intestinal morphology by enhancing intestinal stem-cell activity

BACKGROUND

Chlorogenic acid (CGA), as one of the most abundant naturally occurring phenolic acids, has been documented to be beneficial for intestinal health. However, the underlying mechanism is still not fully understood. The adult intestinal stem cell is the critical driver of epithelial homeostasis and regeneration.

RESULTS

This study hypothesized that CGA exerted intestinal health effects by modulating intestinal stem-cell functions. Lgr5-EGFP mice were treated for 14 days, and intestinal organoids derived from these mice were treated for 3 days, using CGA solution. In comparison with the control group, CGA treatment increased intestinal villous height and crypt depth in mice and augmented the area expansion and the number of budding intestinal organoids. Quantitative polymerase chain reaction (qPCR) analysis revealed that CGA treatment significantly increased the expression of genes coding intestinal stem-cell markers in intestinal tissue and organoids, and upregulated the expression of genes coding secretory cell lineages and enterocytes, although not statistically significantly. Fluorescence-activated cell-sorting analysis further confirmed that CGA augmented the number of stem cells. 5-Ethynyl-2'-deoxyuridine (EdU) incorporation and Ki67 immunostaining results also demonstrated that CGA treatment enhanced intestinal stem-cell proliferation.

CONCLUSION

Altogether, our findings indicate that CGA could activate intestinal stem-cell and epithelial regeneration, which could contribute to the improvement of intestinal morphology or organoid growth of mice. This highlights a promising mechanism for CGA as an excellent candidate for the formulation of dietary supplements and functional foods for intestinal protection. © 2023 Society of Chemical Industry.

Characterization of isogenic mutants with single or double deletions of four phenolic acid esterases in Lactiplantibacillus plantarum TMW1.460

In plants, hydroxycinnamic and hydroxybenzoic acids occur mainly as esters. This study aimed to determine the contribution of individual phenolic acid esterases in Lp. plantarum TMW1.460, which encodes for four esterases: TanA, Lp_0796, Est_1092 and a homolog of Lj0536 and Lj1228 that was termed HceP. To determine which of the phenolic acid esterases present in Lp plantarum TMW1.460 are responsible for esterase activity, mutants with deletions in lp_0796, est_1092, tanB, hceP, or hceP and est_1092 were constructed. The phenotype of wild type strain and mutants was determined with esters of hydroxycinnamic acids (chlorogenic acid and ethyl ferulate) and of hydroxybenzoic acids (methyl gallate, tannic acid and epigallocatechin-3-gallate). Lp. plantarum TMW1.460 hydrolysed chlorogenic acid, methyl ferulate and methyl gallate but not tannic acid or epigallocatechin gallate. The phenotype of mutant strains during growth in mMRS differed from the wild type as follows: Lp. plantarum TMW1.460ΔhceP did not hydrolyse esters of hydroxycinnamic acids; Lp. plantarum TMW1.460ΔtanB did not hydrolyse esters of hydroxybenzoic acids; disruption of est_1092 or Lp_0796 did not alter the phenotype. The phenotype of Lp. plantarum TMW1.460ΔΔhceP/est_1092 was identical to Lp. plantarum TMW1.460ΔhceP. The metabolism of phenolic acids during growth of the mutant strains in broccoli puree and wheat sourdough did not differ from metabolism of the wild type strain. In conclusion, esters of hydroxycinnamic and hydroxybenzoic acids each are hydrolysed by dedicated enzymes. The hydroxycinnamic acid esterase HceP is not expressed, or not active during growth of Lp. plantarum TMW1.460 in all food substrates.

Light plays a critical role in the accumulation of chlorogenic acid in Lonicera macranthoides Hand.-Mazz

Light has important effects on plant metabolism. However, the relationship between the chlorogenic acid (CGA) content and light in plants remains unclear. Here, we investigated the effects of shading treatment on gene expression and CGA content in Lonicera macranthoides Hand.-Mazz. (LM), a widely used medicinal plant. A total of 1891 differentially expressed genes (DEGs) were obtained in flower buds and 819 in leaves in response to light in shading treatment compared to the control sample by RNA-Seq. After shading treatment, the content of CGA in LM leaves decreased significantly by 1.78-fold, the carotenoid content increased, and the soluble sugar and starch contents significantly decreased. WGCNA and the expression of related genes verified by qRT‒PCR revealed that CGA synthesis pathway enzyme genes form a co-expression network with genes for carbohydrate synthesis, photosynthesis, light signalling elements, and transcription factor genes (TFs) that affect the accumulation of CGA. Through a virus-induced gene silencing (VIGS) system and CGA assay in Nicotiana benthamiana (NB), we determined that downregulation of NbHY5 expression decreased the CGA content in NB leaves. In this study, we found that light provides energy and material for the accumulation of CGA in LM, and light affects the expression of CGA accumulation-related genes. Our results show that different light intensities have multiple effects on leaves and flower buds in LM and are able to coregulate LmHY5 expression and CGA synthesis.

Transcription factor NtWRKY33a modulates the biosynthesis of polyphenols by targeting NtMYB4 and NtHCT genes in tobacco

There are abundant polyphenols in tobacco leaves mainly including chlorogenic acid (CGA), rutin, and scopoletin, which not only influence plant growth, development, and environmental adaptation, but also have a great impact on the industrial utilization of tobacco leaves. Few transcription factors regulating the biosynthesis of polyphenols have been identified in tobacco so far. In this study, two NtWRKY33 genes were identified from N. tabacum genome. NtWRKY33a showed higher transcriptional activity than NtWRKY33b, and encoded a nuclear localized protein. Overexpression and knock-out of NtWRKY33a gene revealed that NtWRKY33a inhibited the accumulation of rutin, scopoletin, and total polyphenols, but meanwhile promoted the biosynthesis of CGA. Chromatin immunoprecipitation and Dual-Luc assays indicated that NtWRKY33a could directly bind to the promoters of NtMYB4 and NtHCT, and thus induced the transcription of these two genes. The contents of polyphenols in ntwrky33a, ntmy4, and ntwrky33a/ntmyb4 mutants further confirmed that the repression of NtWRKY33a on the biosynthesis of rutin, scopoletin, and total polyphenols depends on the activity of NtMYB4. Moreover, the promotion of NtHCT by NtWRKY33a modulates the distribution of metabolism flux into the synthesis of CGA. Ectopic expression of NtWRKY33a inhibit the expression of NtSAUR14, NtSAUR59, NtSAUR66, NtIAA4, NtIAA17, and NtIAA19 genes, indicating that NtWRKY33a might be involved in the regulation of plant auxin response. Our study revealed new functions of NtWRKY33a in regulating the synthesis of polyphenols, and provided a promising target for manipulating polyphenols contents in tobacco.

BAHD acyltransferase induced by histone deacetylase inhibitor catalyzes 3-O-hydroxycinnamoylquinic acid formation in bamboo cells

Suspension-cultured cells of a bamboo species (Bambusa multiplex; Bm) produce 3-O-feruloylquinic acid (3-FQA) and 3-O-p-coumaroylquinic acid (3-pCQA) by treatment with the histone deacetylase inhibitor suberoyl bis-hydroxamic acid (SBHA). Acyltransferases catalyzing the formation of 5-O-hydroxycinnamoylquinic acid esters by transesterification from hydroxycinnamoyl-CoAs to the C-5 hydroxy group of quinic acid (hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase, HQT) have been identified in the biosynthesis of chlorogenic acids and monolignols; however, an HQT that catalyzes the acylation of the C-3 hydroxy group of quinic acid has not been identified previously. In the present study, we purified a native HQT from SBHA-treated Bm cells. The purified enzyme preferentially accepted feruloyl-/p-coumaroyl-CoAs as acyl-donors and quinic acid as the acyl-acceptor, and the enzyme specifically formed 3-FQA and 3-pCQA but not 5-O-hydroxycinnamoylquinic acid esters or esters with shikimic acid. A cDNA (BmHQT1) encoding this HQT was isolated. Although BmHQT1 is a phylogenetically unique member of the BAHD acyltransferase superfamily that does not cluster with other HQTs, functional characterization of the recombinant enzyme verified that BmHQT1 catalyzes the regiospecific formation of 3-O-hydroxycinnamoylquinic acid esters. Transcript levels of BmHQT1 markedly increased in Bm cells cultured in the presence of SBHA. Moreover, elevated acetylation levels of histone H3 were observed in the coding region of BmHQT1 in the presence of SBHA, indicating that the induced accumulation of 3-FQA/3-pCQA by SBHA is caused by transcriptional activation of BmHQT1 by the action of SBHA as a histone deacetylase inhibitor. The results demonstrate the utility of HDAC inhibitors for discovery of cryptic secondary metabolites and unknown biosynthetic enzymes.

Mulberry Leaf (Morus alba L.) Extracts and Its Chlorogenic Acid Isomer Component Improve Glucolipotoxicity-Induced Hepatic Lipid Accumulation via Downregulating miR-34a and Decreased Inflammation

Mulberry leaf (Morus alba L.) is used as a traditional medicine and potential health food to treat various metabolic diseases, such as hypertension, diabetes, and hyperlipidemia. However, we sought the mechanisms by which functional components of mulberry leaves mediate diabetic steatohepatitis. We applied an in vitro model of HepG2 cells induced by glucolipotoxicity and evaluated the effects of MLE and its major components nCGA, Crp, and CGA. The results showed that MLE and nCGA reduced liver fat accumulation by inhibiting SREBP-1/FASN, SREBP-2/HMG-CoAR, and activating PPARα/CPT-1. Additionally, MLE and nCGA decreased inflammatory responses associated with NF-κB, TNF-α, and IL-6 to alleviate steatohepatitis. Furthermore, we showed that MLE and nCGA exerted anti-glucolipotoxicity effects by downregulating miR-34a, thus activating SIRT1/AMPK signaling, and subsequently suppressing hepatic lipid accumulation.

Chlorogenic acid improves functional potential of follicles in mouse whole ovarian tissues in vitro

BACKGROUND

Chlorogenic acid (CGA) is one of the well-known polyphenol compounds possessing several important biological and therapeutic functions. In order to optimize a culture system to achieve complete development of follicles, we focused on the effects of CGA supplementation during in vitro culture (IVC) on follicular development, oxidative stress, antioxidant capacity, developmental gene expression, and functional potential in cultured mouse ovarian tissue.

METHODS AND RESULTS

The collected whole murine ovaries were randomly divided into four groups: (1) non-cultured group (control 1) with 7-day-old mouse ovaries, (2) non-cultured group (control 2) with 14-day-old mouse ovaries, (3) cultured group (experimental 1) with the culture plates containing only the basic culture medium, (4) cultured group (experimental 2) with the culture plates containing basic culture medium + CGA (50, 100 and 200 µmol/L CGA). Afterward, histological evaluation, biochemical analyses, the expression assessment of genes related to follicular development and apoptosis as well as the analysis of 17-β-estradiol were performed. The results showed that supplementation of ovarian tissue with the basic culture media using CGA (100 µmol/l) significantly increased the survival, developmental and functional potential of follicles in whole mouse ovarian tissues after 7 days of culture. Furthermore, CGA (100 µmol/L) attenuated oxidative damage and enhanced the concentration of antioxidant capacity along with developmental gene expression.

CONCLUSION

It seems that supplementation of ovarian tissue with culture media using CGA could optimize follicular growth and development in the culture system.

Effects of light quality, photoperiod, CO2 concentration, and air temperature on chlorogenic acid and rutin accumulation in young lettuce plants

Environmental stimuli modulate plant metabolite accumulation, facilitating adaptation to stressful conditions. In this study, the effects of blue and red light, photoperiod, CO2 concentration, and air temperature on the chlorogenic acid (CGA) and rutin contents of lettuce (Lactuca sativa L.) were evaluated. Under continuous blue light and a high CO2 concentration (1000 ppm), the CGA level increased. The increased expression of phenylalanine ammonia-lyase (PAL) and activity of its product were correlated with high expression of cinnamate 4-hydroxylase (C4H) and coumarate 3-hydroxylase (C3H). Furthermore, changes in PAL activity altered the CGA content in lettuce exposed to the three environmental factors, blue light, continuous lighting and high CO2 concentration. In addition, the expression levels of genes related to flavonoid biosynthesis increased in accordance with the promotion of CGA accumulation by the environmental factors. Under continuous blue light, 400 ppm CO2 promoted rutin accumulation to a greater degree compared to 1000 ppm CO2, by downregulating DFR expression. Low air temperature induced CGA accumulation in lettuce grown under continuous blue light and 1000 ppm CO2. Therefore, light quality, photoperiod, CO2 concentration, and air temperature exert synergistic effects on the CGA and rutin contents of lettuce by modulating activity in the corresponding biosynthesis pathways.

Central and Enteric Neuroprotective Effects by Eucommia ulmoides Extracts on Neurodegeneration in Rotenone-induced Parkinsonian Mouse

Parkinson's disease (PD) is a progressive neurodegenerative disease of both the central and peripheral / enteric nervous systems. Oxidative stress and neuroinflammation are associated with the pathogenesis of PD, suggesting that anti-oxidative and anti-inflammatory compounds could be neuroprotective agents for PD. Eucommia ulmoides (EU) is a traditional herbal medicine which exerts neuroprotective effects by anti-inflammatory and anti-oxidative properties. Our previous study showed that treatment with chlorogenic acid, a component of EU, protected against neurodegeneration in the central and enteric nervous systems in a PD model. In this study, we examined the effects of EU extract (EUE) administration on dopaminergic neurodegeneration, glial response and α-synuclein expression in the substantia nigra pars compacta (SNpc), and intestinal enteric neurodegeneration in low-dose rotenone-induced PD model mice. Daily oral administration of EUE ameliorated dopaminergic neurodegeneration and α-synuclein accumulation in the SNpc. EUE treatment inhibited rotenone-induced decreases in the number of total astrocytes and in those expressing the antioxidant molecule metallothionein. EUE also prevented rotenone-induced microglial activation. Furthermore, EUE treatment exerted protective effects against intestinal neuronal loss in the PD model. These results suggest that EU exerts neuroprotective effects in the central and enteric nervous systems of rotenone-induced parkinsonism mice, in part by glial modification.

Chlorogenic Acid Prevents UVA-Induced Skin Photoaging through Regulating Collagen Metabolism and Apoptosis in Human Dermal Fibroblasts

Skin aging is categorized as chronological aging and photo-aging that affected by intrinsic and extrinsic factors. The present study aimed to investigate the anti-aging ability and its underlying mechanism of chlorogenic acid (CGA) on human dermal fibroblasts (HDFs). In this study, CGA specifically up-regulated collagen I (Col1) mRNA and protein expressions and increased the collagen secretion in the supernatant of HDFs without affecting the cell viability, the latter was also demonstrated in BioMAP HDF3CGF system. Under ultraviolet A (UVA)-induced photoaging, CGA regulated collagen metabolism by increasing Col1 expression and decreasing matrix metalloproteinase 1 (MMP1) and MMP3 levels in UVA-irradiated HDFs. The activation of transforming growth factor-β (TGF-β)-mediated Smad2/3 molecules, which is crucial in Col1 synthesis, was suppressed by UVA irradiation and but enhanced at the presence of CGA. In addition, CGA reduced the accumulation of UVA-induced reactive oxygen species (ROS), attenuated the DNA damage and promoted cell repair, resulting in reducing the apoptosis of UVA-irradiated HDFs. In conclusion, our study, for the first time, demonstrate that CGA has protective effects during skin photoaging, especially triggered by UVA-irradiation, and provide rationales for further investigation of CGA being used to prevent or treat skin aging.

The Apoptotic Effect of Caffeic or Chlorogenic Acid on the C32 Cells That Have Simultaneously Been Exposed to a Static Magnetic Field

The induction of apoptosis is one of the main goals of the designed anti-cancer therapies. In recent years, increased attention has been paid to the physical factors such as magnetic fields and to the natural bioactive compounds and the possibilities using them in medicine. Hence, the aim of this study was to evaluate the anti-tumor effect of caffeic or chlorogenic acid in combination with a moderate-strength static magnetic field on C32 melanoma cells by assessing the effect of both factors on the apoptotic process. The apoptosis of the C32 cells was evaluated using a flow cytometry analysis. The expression of the apoptosis-associated genes was determined using the RT-qPCR technique. The caspase activity and the concentration of the oxidative damage markers were also measured. It was found that phenolic acids and a static magnetic field trigger the apoptosis of the C32 cells and also affect the expression of the genes encoding the apoptosis regulatory proteins. In conclusion, our study indicated that both of the phenolic acids and a static magnetic field can be used supportively in the treatment of melanoma and that caffeic acid is more pro-apoptotic than chlorogenic acid.

Mechanism of chlorogenic acid reducing lipopolysaccharideinduced acute lung injury in mice by regulating miR223/NLRP3 axis

OBJECTIVES

Chlorogenic acid has various physiological activities such as antibacterial, anti-inflammatory, and antiviral activities. Studies have shown that chlorogenic acid can alleviate the inflammatory response of mice with acute lung injury (ALI), but the specific mechanism is still unclear. This study aims to investigate whether chlorogenic acid attenuates lipopolysaccharide (LPS)-induced ALI in mice by regulating the microRNA-223 (miR-223)/nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) axis.

METHODS

SPF grade BALBc male mice were randomly divided into a control group, a model group, a chlorogenic acid group, a chlorogenic acid+miR-223 negative control (miR-223 NC) group, and a chlorogenic acid+miR-223 inhibitor (miR-223 antagomir) group, 10 mice in each group. Except the control group, the other groups were instilled with 4 mg/kg LPS through the airway to establish the ALI mouse model. After the modeling, the mice in the chlorogenic acid group were continuously given chlorogenic acid (100 mg/kg) by gavage for 7 d. The chlorogenic acid+miR-223 NC group and the chlorogenic acid+miR-223 antagomir group were given 100 mg/kg chlorogenic acid by gavage every day, and then were injected with 10 μL of miR-223 NC (0.5 nmol/μL) and miR-223 antagomir (0.5 nmol/μL) respectively for 7 consecutive days.The control group and the model group were replaced with normal saline. The lung tissues of mice were taken to measure the ratios of lung wet to dry weight (W/D). The bronchoalveolar lavage fluid of mice was collected to measure the levels of TNF-α, IL-6, and IL-1β by ELISA kit and to count the number of eosinophils (EOS), lymphocytes, neutrophils under light microscope. After HE staining, the pathological changes of lung tissues were observed and lung injury was scored. qRT-PCR method were used to determine the expression levels of miR-223 in lung tissues. Western blotting was used to determine the expression levels of NLRP3 protein in mouse lung tissues. Luciferase reporter assay was used to analyze the targeting relationship of miR-223 to NLRP3.

RESULTS

Compared with the control group, the lung W/D value, the lung injury score and the level of inflammatory factors in the bronchoalveolar lavage fluid were significantly increased in the model group (all P<0.05); the infiltration of inflammatory cells in the lung tissue was severe; the alveolar space was significantly increased; the alveolar wall was significantly thickened; the number of EOS, lymphocytes, and neutrophils in the bronchoalveolar lavage fluid was significantly increased (all P<0.05); the expression levels of miR-223 in lung tissue were significantly decreased (P<0.05); and the protein expression levels of NLRP3 were significantly increased (P<0.05). Compared with the model group, the W/D value of lungs, lung injury score, and levels of inflammatory factors in bronchoalveolar lavage fluid were significantly decreased in the chlorogenic acid group, the chlorogenic acid+miR-223 NC group, and the chlorogenic acid+miR-223 antagomir group (all P<0.05); lung tissues damage was alleviated; the numbers of EOS, lymphocytes, and neutrophils in bronchoalveolar lavage fluid were significantly decreased (all P<0.05); the expression levels of miR-223 in lung tissues were significantly increased (P<0.05); and the expression levels of NLRP3 protein were significantly decreased (P<0.05). Compared with the chlorogenic acid group, the lung W/D value, lung injury score, and inflammatory factor levels in the bronchoalveolar lavage fluid were significantly increased in the chlorogenic acid+miR-223 antagomir group (all P<0.05); lung tissue damage was aggravated; the number of EOS, lymphocytes and neutrophils in bronchoalveolar lavage fluid significantly increased (all P<0.05); the expression levels of miR-223 in lung tissues were significantly decreased (P<0.05); and the expression levels of NLRP3 protein were significantly increased (P<0.05). The results of luciferase reporter assay showed that miR-223 had a targeting relationship with NLRP3.

CONCLUSIONS

Chlorogenic acid may increase the level of miR-223, target the inhibition of NLRP3 expression, reduce LPS-induced inflammatory response in ALI mice, and alleviate pathological damage of lung tissues.

Chicory: Understanding the Effects and Effectors of This Functional Food

Industrial chicory has been the subject of numerous studies, most of which provide clinical observations on its health effects. Whether it is the roasted root, the flour obtained from the roots or the different classes of molecules that enter into the composition of this plant, understanding the molecular mechanisms of action on the human organism remains incomplete. In this study, we were interested in three molecules or classes of molecules present in chicory root: fructose, chlorogenic acids, and sesquiterpene lactones. We conducted experiments on the murine model and performed a nutrigenomic analysis, a metabolic hormone assay and a gut microbiota analysis, associated with in vitro observations for different responses. We have highlighted a large number of effects of all these classes of molecules that suggest a pro-apoptotic activity, an anti-inflammatory, antimicrobial, antioxidant, hypolipidemic and hypoglycemic effect and also an important role in appetite regulation. A significant prebiotic activity was also identified. Fructose seems to be the most involved in these activities, contributing to approximately 83% of recorded responses, but the other classes of tested molecules have shown a specific role for these different effects, with an estimated contribution of 23-24%.

Genomic and transcriptomic inventory of membrane transporters in coffee: Exploring molecular mechanisms of metabolite accumulation

The genus Coffea (Rubiaceae) encompasses a group of perennial plant species, including a commodity crop from which seeds are roasted, ground, and infused to make one of the most appreciated beverages in the world. As an important tropical crop restricted to specific regions of the world, coffee production is highly susceptible to the effects of environmental instabilities (i.e., local year-to-year weather fluctuations and global climate change) and threatening pest pressures, not to mention an increasing quality rigor by consumers in industrialized countries. Specialized metabolites are substances that largely affect plant-environment interactions as well as how consumers experience agricultural products. Membrane transporters are key targets, albeit understudied, for understanding and tailoring the spatiotemporal distribution of specialized metabolites as they mediate and control molecular trafficking and substance accumulation. Therefore, we analyzed the transportome of C. canephora encoded within the 25,574 protein-coding genes annotated in the genome of this species and identified 1847 putative membrane transporters. Following, we mined 152 transcriptional profiles of C. canephora and C. arabica and performed a comprehensive co-expression analysis to identify transporters potentially involved in the accumulation of specialized metabolites associated with beverage quality and bioactivity attributes. In toto, this report points to an avenue of possibilities on Coffea genomic and transcriptomic data mining for genetic breeding strategies, which can lead to the development of new, resilient varieties for more sustainable coffee production systems.

Finger sweat analysis enables short interval metabolic biomonitoring in humans

Metabolic biomonitoring in humans is typically based on the sampling of blood, plasma or urine. Although established in the clinical routine, these sampling procedures are often associated with a variety of compliance issues, which are impeding time-course studies. Here, we show that the metabolic profiling of the minute amounts of sweat sampled from fingertips addresses this challenge. Sweat sampling from fingertips is non-invasive, robust and can be accomplished repeatedly by untrained personnel. The sweat matrix represents a rich source for metabolic phenotyping. We confirm the feasibility of short interval sampling of sweat from the fingertips in time-course studies involving the consumption of coffee or the ingestion of a caffeine capsule after a fasting interval, in which we successfully monitor all known caffeine metabolites as well as endogenous metabolic responses. Fluctuations in the rate of sweat production are accounted for by mathematical modelling to reveal individual rates of caffeine uptake, metabolism and clearance. To conclude, metabotyping using sweat from fingertips combined with mathematical network modelling shows promise for broad applications in precision medicine by enabling the assessment of dynamic metabolic patterns, which may overcome the limitations of purely compositional biomarkers.

Effect of alcoholic and acetous fermentations on the phenolic acids of Kei-apple (Dovyalis caffra L.) fruit

BACKGROUND

The Kei apple is a tree found on the African continent. Limited information exists on the effect of alcoholic and acetous fermentation on the phytochemicals of Kei apple. The fruit has increased concentrations of l-malic, ascorbic, and phenolic acids among other compounds. Juice was co-inoculated with Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) to induce alcoholic fermentation (AF). Acetous fermentation followed AF, using an acetic acid bacteria (AAB) consortium.

RESULTS

Saccharomyces cerevisiae + Sp wines and vinegars had the highest pH. Total acidity, soluble solids and l-malic acid decreased during AF and acetous fermentation, and was highest in Sc wines and vinegars. Volatile acidity (VA) concentration was highest in Sp vinegars but was not significantly different from Sc and Sc + Sp vinegars. Gallic acid was highest in Sp wines and vinegars, whereas syringic acid was highest in Sc wines and vinegars. The Sc + Sp wines were highest in caffeic, p-coumaric, and protocatechuic acids. Schizosaccharomyces pombe vinegars were highest in caffeic and p-coumaric acids. Highest concentrations of ferulic and sinapic acids were found in Sp and Sc wines, respectively. Chlorogenic acid was most abundant phenolic acid in both wines and vinegars.

CONCLUSION

Saccharomyces cerevisiae + Sp and Sc fermentation had a positive effect on most phenolic acids; Sc + AAB had an increased effect on syringic and chlorogenic acids, whereas Sp + AAB resulted in an increase in gallic, caffeic, and p-coumaric acids. The AAB selected had minimal performance with respect to VA production in comparison to commercial vinegars. Acetic acid bacteria selection for acetous fermentation should therefore be reconsidered and the decrease of certain phenolic acids during acetous fermentation needs to be investigated. © 2021 Society of Chemical Industry.

LjaFGD: Lonicera japonica functional genomics database

Lonicera japonica Thunb., a traditional Chinese herb, has been used for treating human diseases for thousands of years. Recently, the genome of L. japonica has been decoded, providing valuable information for research into gene function. However, no comprehensive database for gene functional analysis and mining is available for L. japonica. We therefore constructed LjaFGD (www.gzybioinformatics.cn/LjaFGD and bioinformatics.cau.edu.cn/LjaFGD), a database for analyzing and comparing gene function in L. japonica. We constructed a gene co-expression network based on 77 RNA-seq samples, and then annotated genes of L. japonica by alignment against protein sequences from public databases. We also introduced several tools for gene functional analysis, including Blast, motif analysis, gene set enrichment analysis, heatmap analysis, and JBrowse. Our co-expression network revealed that MYB and WRKY transcription factor family genes were co-expressed with genes encoding key enzymes in the biosynthesis of chlorogenic acid and luteolin in L. japonica. We used flavonol synthase 1 (LjFLS1) as an example to show the reliability and applicability of our database. LjaFGD and its various associated tools will provide researchers with an accessible platform for retrieving functional information on L. japonica genes to further biological discovery.

A R2R3-MYB transcriptional activator LmMYB15 regulates chlorogenic acid biosynthesis and phenylpropanoid metabolism in Lonicera macranthoides

Lonicera macranthoides Hand-Mazz is an important medicinal plant widely distributed in southern China that has long been used in Chinese traditional medicines. Chlorogenic acid (CGA, 3-caffeoylquinic acid) is the major biologically active ingredient in L. macranthoides. Although key CGA biosynthetic genes have been well documented, their transcriptional regulation remains largely unknown. In this study, we observed that a R2R3 MYB transcription factor LmMYB15 showed a significant correlation with CGA content, indicating its potential role in CGA biosynthesis. A yeast two-hybrid assay suggested that LmMYB15 functions as a transcriptional activator. Overexpression of LmMYB15 in tobacco led to increased accumulation of CGA compared to those in wild-type leaves. To elucidate its functional mechanism, genome-wide DAP-seq was employed and identified the conserved binding motifs of LmMYB15, that is [(C/T) (C/T) (C/T) ACCTA(C/A) (C/T) (A/T)], as well as its direct downstream target genes, including 4CL, MYB3, MYB4, KNAT6/7, IAA26, and ETR2. Subsequently, yeast one-hybrid and dual-luciferase reporter assays verified that LmMYB15 could bind and activate the promoters of 4CL, MYB3 and MYB4, thereby facilitating CGA biosynthesis and phenylpropanoid metabolism. Our findings provide a new track for breeding strategies aiming to enhance CGA content in L. macranthoides that can significantly contribute to better mechanical properties.

Comparison of plasma and pulmonary availability of chlorogenic acid, forsythiaside A and baicalin after intratracheal and intravenous administration of Shuang-Huang-Lian injection

ETHNOPHARMACOLOGICAL RELEVANCE

The off-label nebulization of Shuang-Huang-Lian (SHL) injection is often utilized to treat respiratory tract infections in China. However, the pulmonary biopharmaceutics of SHL was generally unknown, limiting the rational selection of therapeutic dose and dose frequency.

AIM OF THE STUDY

To characterize the size distribution of nebulized aerosols and to compare the pharmacokinetics and the lung distribution of three chemical makers of SHL, chlorogenic acid (CHA), forsythiaside A (FTA) and baicalin (BC), after intratracheal and intravenous administration of SHL to rats.

MATERIALS AND METHODS

The droplet size distribution profiles over nebulization process were dynamically monitored using a laser diffraction method whereas the levels of CHA, FTA and BC in plasma, lung tissues and bronchoalveolar lavage fluids (BALF) were determined by a validated LC-MS/MS assay. The pulmonary anti-inflammatory efficacy was evaluated using a lipopolysaccharide (LPS) induced lung inflammation model as indicated by the level of tumor necrosis factor-α (TNF-α) in BALF.

RESULTS

The nebulization of SHL showed good inhalability and allowed the aerosols to reach the upper or lower respiratory tract dependent on the performance of selected nebulizers. Following intratracheal administration of SHL at different doses, CHA, FTA and BC were absorbed into the bloodstream with the mean absorption time being 67.5, 63.5 and 114 min, respectively, rendering mean absolute bioavailabilities between 42.4% and 61.4% roughly independent of delivered dose. Relative to the intravenous injection, the intrapulmonary delivery increased the lung-to-plasma concentration ratios of CHA, FTA and BC by more than 100 folds and markedly improved the lung availability by 563-676 folds, leading to enhanced and prolonged lung retention. The production of TNF-α in BALF was decreased by ~50% at an intratracheal dose of 125 μL/kg SHL to LPS-treated mice.

CONCLUSION

The nebulization delivery of SHL is a promising alternative to the intravenous injection for the treatment of respiratory tract infections.

Simulated Gastrointestinal Biotransformation of Chlorogenic Acid, Flavonoids, Flavonolignans and Triterpenoid Saponins in Cecropia obtusifolia Leaf Extract

It is well known that biotransformation processes in the human body are crucial to form potentially bioactive metabolites from particular classes of natural products. However, little research has been conducted concerning the bioavailability of polyphenols, especially in the colon. The gastrointestinal stability and colonic biotransformation of the crude extract of the leaves of Cecropia obtusifolia, rich in flavone C-glycosides, was investigated under in vitro conditions, and the processing and interpretation of results were facilitated by using an automated machine learning model. This investigation revealed that flavone C-glycosides and flavonolignans from C. obtusifolia were stable throughout their passage in the simulated gastrointestinal tract including the colon phase. On the other hand, the colon bacteria extensively metabolized chlorogenic acid, flavonol, and triterpenoid O-glycosides. This investigation revealed that the colonic microbiota has an important role in the biotransformation of some chemical constituents of this extract.

RNAi Modulation of Chlorogenic Acid and Lignin Deposition in Nicotiana tabacum and Insufficient Compensatory Metabolic Cross-Talk

Chlorogenic acid (CGA) and guaiacyl/syringyl (G/S) lignin formation involves hydroxycinnamoyl ester intermediacy, the latter formed via hydroxycinnamoyl CoA:shikimate hydroxycinnamoyl transferase (HCT) and hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase (HQT) activities. HQT and HCT RNAi silencing of a commercial tobacco (Nicotiana tabacum) K326 line was examined herein. NtHQT gene silencing gave relatively normal plant phenotypes, with CGA levels reduced (down to 1% of wild type) with no effects on lignin. RNAi NtHCT silencing had markedly adverse phenotypes (e.g., stunted, multiple stems, delayed flowering, with senescence delayed by several months). Lignin contents were partially lowered, with a small increase in cleavable p-hydroxyphenyl (H) monomers; those plants had no detectable CGA level differences relative to wild type. In vitro NtHCT kinetic parameters revealed preferential p-coumaroyl CoA and shikimate esterification, as compared to other structurally related potential acyl group donors and acceptors. In the presence of coenzyme A, NtHCT catalyzed the reverse reaction. Site-directed mutagenesis of NtHCT (His153Ala) abolished enzymatic activity. NtHQT, by comparison, catalyzed preferential conversion of p-coumaroyl CoA and quinic acid to form p-coumaroyl quinate, the presumed CGA precursor. In sum, metabolic pathways to CGA and lignins appear to be fully independent, and previous conflicting reports of substrate versatilities and metabolic cross-talk are resolved.

Multiple co-pigments of quercetin and chlorogenic acid blends intensify the color of mulberry anthocyanins: insights from hyperchromicity, kinetics, and molecular modeling investigations

BACKGROUND

The effect of multiple co-pigments on the color intensification of mulberry anthocyanins (ACs) using spectroscopic techniques in combination with a molecular docking study was studied. The hyperchromicity of ACs co-pigmented with chlorogenic acid (CH) and quercetin (Q) blends was measured and their color stability in liquid and encapsulated particle models was evaluated.

RESULTS

Multiple co-pigments exhibited higher hyperchromicity, pK_H -values, and heat-stability than their individual counterparts. Surflex-docking findings confirmed that stronger binding occurred between multiple ligands and AC than single ones due to their extra -OH, -COOH groups, and delocalization systems. The binding was allowed by increased H-bonding, van der Waals forces, and π-π sites by the extra groups of the multiple co-pigments with AC in aqueous juice and whey particle-based models.

CONCLUSION

This is the first report of the ternary mixture of phenolic acid-flavonol-anthocyanin which could be used as promising food red-colorants. © 2020 Society of Chemical Industry.

Genetic Architecture Underlying the Metabolites of Chlorogenic Acid Biosynthesis in Populus tomentosa

Chlorogenic acid (CGA) plays a crucial role in defense response, immune regulation, and the response to abiotic stress in plants. However, the genetic regulatory network of CGA biosynthesis pathways in perennial plants remains unclear. Here, we investigated the genetic architecture for CGA biosynthesis using a metabolite-based genome-wide association study (mGWAS) and expression quantitative trait nucleotide (eQTN) mapping in a population of 300 accessions of Populus tomentosa. In total, we investigated 204 SNPs which were significantly associated with 11 metabolic traits, corresponding to 206 genes, and were mainly involved in metabolism and cell growth processes of P. tomentosa. We identified 874 eQTNs representing 1066 genes, in which the expression and interaction of causal genes affected phenotypic variation. Of these, 102 genes showed significant signatures of selection in three geographical populations, which provided insights into the adaptation of CGA biosynthesis to the local environment. Finally, we constructed a genetic network of six causal genes that coordinately regulate CGA biosynthesis, revealing the multiple regulatory patterns affecting CGA accumulation in P. tomentosa. Our study provides a multiomics strategy for understanding the genetic basis underlying the natural variation in the CGA biosynthetic metabolites of Populus, which will enhance the genetic development of abiotic-resistance varieties in forest trees.

Integrated transcriptome, small RNA and degradome sequencing approaches proffer insights into chlorogenic acid biosynthesis in leafy sweet potato

Leafy sweet potato is rich in total phenolics (TP) which play key roles in health protection, the chlorogenic acid (CGA) constitutes the major components of phenolic compounds in leafy sweet potato. Unfortunately, the mechanism of CGA biosynthesis in leafy sweet potato is unclear. To dissect the mechanisms of CGA biosynthesis, we performed transcriptome, small RNA (sRNA) and degradome sequencing of one low-CGA content and one high-CGA content genotype at two stages. A total of 2,333 common differentially expressed genes (DEGs) were identified, and the enriched DEGs were related to photosynthesis, starch and sucrose metabolism and phenylpropanoid biosynthesis. The functional genes, such as CCR, CCoAOMT and HCT in the CGA biosynthetic pathway were down-regulated, indicating that the way to lignin was altered, and two possible CGA biosynthetic routes were hypothesized. A total of 38 DE miRNAs were identified, and 1,799 targets were predicated for 38 DE miRNAs by using in silico approaches. The target genes were enriched in lignin and phenylpropanoid catabolic processes. Transcription factors (TFs) such as apetala2/ethylene response factor (AP2/ERF) and Squamosa promoter binding protein-like (SPL) predicated in silico were validated by degradome sequencing. Association analysis of the DE miRNAs and transcriptome datasets identified that miR156 family negatively targeted AP2/ERF and SPL. Six mRNAs and six miRNAs were validated by qRT-PCR, and the results showed that the expression levels of the mRNAs and miRNAs were consistent with the sequencing data. This study established comprehensive functional genomic resources for the CGA biosynthesis, and provided insights into the molecular mechanisms involving in this process. The results also enabled the first perceptions of the regulatory roles of mRNAs and miRNAs, and offered candidate genes for leafy sweet potato improvements.

Effect of chlorogenic acid on alleviating inflammation and apoptosis of IPEC-J2 cells induced by deoxyniyalenol

Deoxynivalenol (DON) is extensively detected in many kinds of foods and feeds to harm human and animal health. This research aims to investigate the effect of chlorogenic acid (CGA) on alleviating inflammation and apoptosis of swine jejunal epithelial cells (IPEC-J2) triggered by DON. The results demonstrated that cell viability was decreased when DON concentrations increased or incubation time expanded. The pretreatment with CGA (40 μg/mL) for 1 h increased cell viability, decreased lactate dehydrogenase (LDH) release and apoptosis in cells triggered by DON at 0.5 μg/mL for 6 h, compared with the DON alone-treated cells. Moreover, the mRNA abundances of IL-8, IL-6, TNF-α, COX-2, caspase-3, Bax and ASCT2 genes, and protein expressions of COX-2, Bax and ASCT2 were significantly down-regulated; while the mRNA abundances of ZO-1, claudin-1, occludin, PePT1 and GLUT2 genes, and protein expressions of ZO-1, claudin-1 and PePT1 were significantly up-regulated in the CGA + DON group, compared with the DON alone group. This study indicated that CGA pretreatment alleviated cytotoxicity, inflammation and apoptosis in DON-triggered IPEC-J2 cells, and protected intestinal cell integrity from DON damages.

Identification of the metabolites of isochlorogenic acid A in rats by UHPLC-Q-Exactive Orbitrap MS

CONTENT

Isochlorogenic acid A, one of the main components of Duhaldea nervosa (Wallich ex Candolle) A. Anderberg (Asteraceae), is a folk medicine used to treat a variety of diseases including fracture and rheumatoid arthritis. Despite its widespread use, the metabolism of isochlorogenic acid A in vivo has not been fully studied.

OBJECTIVE

An analytical strategy based on UHPLC-Q-Exactive Orbitrap MS is proposed for the detection and identification of the metabolites of isochlorogenic acid A in rats.

MATERIALS AND METHODS

Six male Sprague-Dawley rats (180 ± 20 g) were randomly divided into two groups. Then, blood and tissue samples were obtained after oral administration of isochlorogenic acid A (200 mg/kg). All the samples were pre-treated by the Solid Phase Extraction (SPE) method. Next, the samples were analysed by UHPLC-Q-Exactive Orbitrap MS. Finally, the metabolites were identified based on the metabolomic workflow template.

RESULTS

A total of 33 metabolites were identified in rat plasma, with 30 of them being reported for the first time. The distribution of all metabolites in tissues was first investigated, three of them were widely distributed in liver, lungs, and kidneys. The corresponding reactions including methylation, hydrolysis, sulphate conjugation, glucuronide conjugation, as well as their composite reactions, are reported in this study.

DISCUSSION AND CONCLUSIONS

This method has wide-scale application prospects in the identification of metabolites. Considering that limited research has been conducted in this area, this study proposes metabolic pathways to further understand mechanisms of isochlorogenic acid A and the forms that are truly effective in vivo.

Metabolomic and Transcriptomic Analyses Reveal that Blue Light Promotes Chlorogenic Acid Synthesis in Strawberry

Light-emitting diodes (LEDs) have been widely used in plant factories and agricultural facilities. Different LEDs can be designed in accordance with the light quality and intensity requirements of different plants, allowing the regulation of plant growth and development, as well as metabolic processes. Blue and red lights have significant effects on anthocyanin metabolism in strawberry fruit, but their effects on other metabolites are unknown. Here, we studied the effects of blue and red lights on the metabolism and gene expression of strawberry using metabolomics combined with transcriptomics. A total of 33 differentially expressed metabolites (DEMs) and 501 differentially expressed genes (DEGs) were isolated and identified. Among these DEMs, chlorogenic acid synthesis was upregulated by the blue light compared with the red light. Co-expression network analysis of DEMs and DEGs revealed that the expression of hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (FvHCT), the main gene in the chlorogenic acid synthetic pathway, was induced by blue light. Using multi-omics-based approach, our results suggest that different LED lights have multiple effects on strawberry fruit, with blue light able to co-upregulate chlorogenic acid synthesis and FvHCT gene expression.

Chlorogenic Acid Enriched Green Coffee Ameliorated Renal Injury in Rats

The incidence of acute kidney injury (AKI) during the treatment with gentamicin (GM) is very common in hospitalized patients. Green coffee bean, containing chlorogenic acid (CGA) has been reported to improve non communicable diseases. In the present study, CGA enriched fraction of green coffee bean was evaluated on GM induced nephrotoxicity in rats. It was a preclinical case-controlled experimental intervention conducted in the Department of Pharmacology, R G Kar Medical College, Kolkata, India from 2016-2019 using animal model. CGA content of green coffee bean extract (GCBE) was isolated and quantified by high performance thin layer chromatography (HPTLC) (6.426%). The rats were treated with GCBE at the dose of 100, 200 and 400mg/kg in gentamicin (GM) induced AKI for five consecutive days. At day 6, the renal function was assessed through analysing urine, blood and renal tissues. GCBE dose dependently and significantly (p<0.001) lowered blood urea, creatinine and potassium while, enhanced sodium compared to AKI control. Moreover, it showed significant elevation in glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and reduction in lipid peroxides (p<0.001). It was suggested that chlorogenic acid of green coffee seed can protect kidney through down regulation of p53 transcription factor and thereby attenuation of oxidative stress, inflammation and apoptotic process in renal tubules.

The Protective Effect of Chlorogenic Acid on Vascular Senescence via the Nrf2/HO-1 Pathway

The world faces the serious problem of aging. In this study, we aimed to investigate the effect of chlorogenic acid (CGA) on vascular senescence. C57/BL6 female mice that were 14 ± 3 months old were infused with either Angiotensin II (AngII) or saline subcutaneously for two weeks. These mice were administered CGA of 20 or 40 mg/kg/day, or saline via oral gavage. AngII infusion developed vascular senescence, which was confirmed by senescence associated-β-galactosidase (SA-β-gal) staining. CGA administration attenuated vascular senescence in a dose-dependent manner, in association with the increase of Sirtuin 1 (Sirt1) and endothelial nitric oxide synthase (eNOS), and with the decrease of p-Akt, PAI-1, p53, and p21. In an in vitro study, with or without pre-treatment of CGA, Human Umbilical Vein Endothelial Cells (HUVECs) were stimulated with H2O2 for an hour, then cultured in the absence or presence of 0.5-5.0 μM CGA for the indicated time. Endothelial cell senescence was induced by H2O2, which was attenuated by CGA treatment. Pre-treatment of CGA increased Nrf2 in HUVECs. After H2O2 treatment, translocation of Nrf2 into the nucleus and the subsequent increase of Heme Oxygenase-1 (HO-1) were observed earlier in CGA-treated cells. Furthermore, the HO-1 inhibitor canceled the beneficial effect of CGA on vascular senescence in mice. In conclusion, CGA exerts a beneficial effect on vascular senescence, which is at least partly dependent on the Nuclear factor erythroid 2-factor 2 (Nrf2)/HO-1 pathway.

Differential Metabolic Responses Caused by the Most Important Insect Pest of Coffee Worldwide, the Coffee Berry Borer (Hypothenemus hampei)

The world's coffee supply is threatened by the coffee berry borer, Hypothenemus hampei, the most destructive pest affecting coffee production and quality. This study hypothesized that coffee berry borer infestation induces distinct metabolic responses in the green coffee seeds of Coffea arabica and Coffea canephora (robusta). A targeted metabolomics approach was conducted using liquid chromatography tandem mass spectrometry to quantify intracellular metabolites in infested and uninfested arabica and robusta green seeds. In parallel, the seed biomass content and composition were assessed for the same conditions. Coffee berry borer attack induced increases in the levels of chlorogenic acids in arabica seeds, whereas organic acids and sugar alcohols were more abundant in infested robusta seeds. Most importantly, a set of compounds was identified as biomarkers differentiating the metabolic response of these taxa to the coffee berry borer.

Exploration of Binding Mechanism of a Potential Streptococcus pneumoniae Neuraminidase Inhibitor from Herbaceous Plants by Molecular Simulation

Streptococcus pneumoniae can cause diseases such as pneumonia. Broad-spectrum antibiotic therapy for Streptococcus pneumoniae is increasingly limited due to the emergence of drug-resistant strains. The development of novel drugs is still currently of focus. Abundant polyphenols have been demonstrated to have antivirus and antibacterial ability. Chlorogenic acid is one of the representatives that has been proven to have the potential to inhibit both the influenza virus and Streptococcus pneumoniae. However, for such a potential neuraminidase inhibitor, the interaction mechanism studies between chlorogenic acid and Streptococcus pneumoniae neuraminidase are rare. In the current study, the binding mechanism of chlorogenic acid and Streptococcus pneumoniae neuraminidase were investigated by molecular simulation. The results indicated that chlorogenic acid might establish the interaction with Streptococcus pneumoniae neuraminidase via hydrogen bonds, salt bridge, and cation-π. The vital residues involved Arg347, Ile348, Lys440, Asp372, Asp417, and Glu768. The side chain of Arg347 might form a cap-like structure to lock the chlorogenic acid to the active site. The results from binding energy calculation indicated that chlorogenic acid had strong binding potential with neuraminidase. The results predicted a detailed binding mechanism of a potential Streptococcus pneumoniae neuraminidase inhibitor, which will be provide a theoretical basis for the mechanism of new inhibitors.

Should I stay or should I go: are chlorogenic acids mobilized towards lignin biosynthesis?

Chlorogenic acids (CGAs) and the biopolymer lignin are both products of the phenylpropanoid pathway. Whereas CGAs have been reported to play a role during stress responses, lignin is a major component of secondary cell walls, providing physical strength and hydrophobicity to supportive and water-conducting tissues. Because the chemical structure of CGAs largely resembles those of some lignin intermediates and because CGAs can be converted back to hydroxycinnamoyl-CoAs in vitro, CGAs have been considered authentic intermediates of the lignin biosynthetic pathway. However, it is still unclear whether and how the CGA pool can be channeled towards the production of lignin monomers in response to developmental or environmental signals. Comprehensive studies on the catalytic activity of recombinant enzymes together with functional characterizations in planta have been very useful in understanding the potential interdependence between these two metabolic routes. Here we present the current understanding on CGA metabolism and discuss the biochemical and molecular evidence of the metabolic re-routing of CGAs towards lignin.

Novel Fluorescence-Based Method To Characterize the Antioxidative Effects of Food Metabolites on Lipid Droplets in Cultured Hepatocytes

A fluorescence microscopic method for characterizing size, quantity, and oxidation of lipid droplets (LDs) in HepG2 cells was developed. LDs were induced by palmitic (PA), oleic (OA), or linoleic acids (LA) and stained with two fluorescent probes for neutral lipids and lipid peroxides. Each fatty acid increased the number of LDs and oxidized LDs (oxLDs) and the degree of LD oxidation time dependently, as well as increased intracellular triglyceride hydroperoxides. LDs induced by LA without 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) showed the most significant oxidation degree over PA and OA, especially in large LDs (area ≥ 3 μm², oxLD/LD = 52.3 ± 21.7%). Under this condition, two food-derived antioxidants were evaluated, and both of them significantly improved the LD characteristics. Moreover, chlorogenic acid reduced the quantity of large LDs by 74.0-87.6% in a dose-dependent manner. The proposed method provides a new approach to evaluate the effect of dietary antioxidants on LD characteristics.