Dicaffeoylquinic Acid-Enriched Fraction of Cichorium glandulosum Seeds Attenuates Experimental Type 1 Diabetes via Multipathway Protection

Screening of α-Glucosidase Inhibitors in Cichorium glandulosum Boiss. et Huet Extracts and Study of Interaction Mechanisms

Cichorium glandulosum Boiss. et Huet (CGB) extract has an α-glucosidase inhibitory effect (IC50 = 59.34 ± 0.07 μg/mL, positive control drug acarbose IC50 = 126.1 ± 0.02 μg/mL), but the precise enzyme inhibitors implicated in this process are not known. The screening of α-glucosidase inhibitors in CGB extracts was conducted by bioaffinity ultrafiltration, and six potential inhibitors (quercetin, lactucin, 3-O-methylquercetin, hyperoside, lactucopicrin, and isochlorogenic acid B) were screened as the precise inhibitors. The binding rate calculations and evaluation of enzyme inhibitory effects showed that lactucin and lactucopicrin exhibited the greatest inhibitory activities. Next, the inhibiting effects of the active components of CGB, lactucin and lactucopicrin, on α-glucosidase and their mechanisms were investigated through α-glucosidase activity assay, enzyme kinetics, multispectral analysis, and molecular docking simulation. The findings demonstrated that lactucin (IC50 = 52.76 ± 0.21 μM) and lactucopicrin (IC50 = 17.71 ± 0.64 μM) exhibited more inhibitory effects on α-glucosidase in comparison to acarbose (positive drug, IC50 = 195.2 ± 0.30 μM). Enzyme kinetic research revealed that lactucin inhibits α-glucosidase through a noncompetitive inhibition mechanism, while lactucopicrin inhibits it through a competitive inhibition mechanism. The fluorescence results suggested that lactucin and lactucopicrin effectively reduce the fluorescence of α-glucosidase by creating lactucin-α-glucosidase and lactucopicrin-α-glucosidase complexes through static quenching. Furthermore, the circular dichroism (CD) and Fourier transform infrared spectroscopy (FT-IR) analyses revealed that the interaction between lactucin or lactucopicrin and α-glucosidase resulted in a modification of the α-glucosidase's conformation. The findings from molecular docking and molecular dynamics simulations offer further confirmation that lactucopicrin has a robust binding affinity for certain residues located within the active cavity of α-glucosidase. Furthermore, it has a greater affinity for α-glucosidase compared to lactucin. The results validate the suppressive impact of lactucin and lactucopicrin on α-glucosidase and elucidate their underlying processes. Additionally, they serve as a foundation for the structural alteration of sesquiterpene derived from CGB, with the intention of using it for the management of diabetic mellitus.

In Vitro Gastrointestinal Digestion of Various Sweet Potato Leaves: Polyphenol Profiles, Bioaccessibility and Bioavailability Elucidation

The chemical composition discrepancies of five sweet potato leaves (SPLs) and their phenolic profile variations during in vitro digestion were investigated. The results indicated that Ecaishu No. 10 (EC10) provided better retention capacity for phenolic compounds after drying. Furthermore, polyphenols were progressively released from the matrix as the digestion process proceeded. The highest bioaccessibility of polyphenols was found in EC10 intestinal chyme at 48.47%. For its phenolic profile, 3-, 4-, and 5-monosubstituted caffeoyl quinic acids were 9.75%, 57.39%, and 79.37%, respectively, while 3,4-, 3,5-, and 4,5-disubstituted caffeoyl quinic acids were 6.55, 0.27 and 13.18%, respectively. In contrast, the 3,4-, 3,5-, 4,5-disubstituted caffeoylquinic acid in the intestinal fluid after dialysis bag treatment was 62.12%, 79.12%, and 62.98%, respectively, which resulted in relatively enhanced bioactivities (DPPH, 10.51 μmol Trolox/g; FRAP, 8.89 μmol Trolox/g; ORAC, 7.32 μmol Trolox/g; IC50 for α-amylase, 19.36 mg/g; IC50 for α-glucosidase, 25.21 mg/g). In summary, desirable phenolic acid release characteristics and bioactivity of EC10 were observed in this study, indicating that it has potential as a functional food ingredient, which is conducive to the exploitation of the sweet potato processing industry from a long-term perspective.

Chemometric Discrimination of Cichorium glandulosum Boiss. et Huet and Cichorium intybus L. via Their Metabolic Profiling, Antioxidative, and Hypoglycemic Activities

Cichorium glandulosum Boiss. et Huet (CG) and Cichorium intybus L. (CI) are widely used as the main raw material of functional food with hepatoprotective and hypoglycemic effects. Due to the lack of comparison on the chemical ingredients and efficacy, they were often used imprecisely and interchangeably. It is necessary to distinguish between them. With the plant metabolomics based on high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) and multivariate chemometric techniques, the chemical ingredients were characterized and 59 compounds between CG and CI were classified. As for antioxidative and hypoglycemic activities in vitro, CI extraction exhibited better antioxidant activity than CG, while CG extraction showed stronger hypoglycemic activity. Furthermore, a bivariate correlation between the chemical composition and efficacy of the extract was also analyzed, and three differentially strong correlation components between CI and CG were prepared, and the antioxidative and hypoglycemic efficacies were compared in vivo and different active phenotypes were obtained. Finally, we revealed chemical and biological differences between CG and CI, providing a basis for achieving better quality control and developing more effective functional foods.

Advances in Anti-Diabetic Cognitive Dysfunction Effect of Erigeron Breviscapus (Vaniot) Hand-Mazz

Diabetic cognitive dysfunction (DCD) is the decline in memory, learning, and executive function caused by diabetes. Although its pathogenesis is unclear, molecular biologists have proposed various hypotheses, including insulin resistance, amyloid β hypothesis, tau protein hyperphosphorylation hypothesis, oxidative stress and neuroinflammation. DCD patients have no particular treatment options and current pharmacological regimens are suboptimal. In recent years, Chinese medicine research has shown that herbs with multi-component, multi-pathway and multi-target synergistic activities can prevent and treat DCD. Yunnan is home to the medicinal herb Erigeron breviscapus (Vant.) Hand-Mazz. (EBHM). Studies have shown that EBHM and its active components have a wide range of pharmacological effects and applications in cognitive disorders. EBHM's anti-DCD properties have been seldom reviewed. Through a literature study, we were able to evaluate the likely pathophysiology of DCD, prescribe anti-DCD medication and better grasp EBHM's therapeutic potential. EBHM's pharmacological mechanism and active components for DCD treatment were also summarized.

Polysaccharide from Hovenia dulcis (Guaizao) improves pancreatic injury and regulates liver glycometabolism to alleviate STZ-induced type 1 diabetes mellitus in rats

Hovenia dulcis is a traditional medicinal and edible plant and has a major geographical presence in China. In this study, a polysaccharide purified from H. dulcis (HDPs-2A) was found to ameliorate type 1 diabetes mellitus (T1DM) in streptozotocin-induced diabetic rat. HDPs-2A treatment resulted in significantly lower fasting blood glucose levels, but higher body weight, plasma insulin, and liver glycogen levels. Moreover, HDPs-2A improved dyslipidemia, pancreatic oxidative stress, and reduced serum pro-inflammatory factors. In addition, HDPs-2A up-regulated PDX-1, activated and up-regulated IRS2 expression, and regulated apoptosis and regeneration of islet β cells to recover islet β-cell function injury in TIDM rats. HDPs-2A also up-regulated the expression of pancreatic GK and GLUT2 to improve insulin secretion ability of islet β-cells, ultimately improving the glucose metabolism disorder of T1DM rats. Moreover, HDPs-2A significantly up-regulated the expression of GK and down-regulated the expression of G6Pase in liver to improve liver glycogen synthesis, inhibit liver gluconiogenesis, and improve liver glucose metabolism disorder of T1DM rats. In summary, the hypoglycemic mechanisms of HDPs-2A may include regulating the regeneration and apoptosis of islet β-cells and activating liver glycometabolism-related signaling pathways in T1DM rats.

Potential Mechanisms Involved in the Protective Effect of Dicaffeoylquinic Acids from Artemisia annua L. Leaves against Diabetes and Its Complications

Diabetes mellitus is a chronic disease affecting the globe and its incidence is increasing pandemically. The use of plant-derived natural products for diabetes management is of great interest. Polar fraction of Artemisia annua L. leaves has shown antidiabetic activity in vivo. In the present study, three major compounds were isolated from this polar fraction; namely, 3,5-dicaffeoylquinic acid (1); 4,5-dicaffeoylquinic acid (2), and 3,4- dicaffeoylquinic acid methyl ester (3), using VLC-RP-18 and HPLC techniques. The potential protective effects of these compounds against diabetes and its complications were investigated by employing various in vitro enzyme inhibition assays. Furthermore, their antioxidant and wound healing effectiveness were evaluated. Results declared that these dicaffeoylquinic acids greatly inhibited DPPIV enzyme while moderately inhibited α-glucosidase enzyme, where compounds 1 and 3 displayed the most prominent effects. In addition, compound 3 showed pronounced inhibition of α-amylase enzyme. Moreover, these compounds markedly inhibited aldose reductase enzyme and exerted powerful antioxidant effects, among which compound 3 exhibited the highest activity implying a notable potentiality in impeding diabetes complications. Interestingly, compounds 2 and 3 moderately accelerated scratch wound healing. Our findings suggest that these dicaffeoylquinic acids can be promising therapeutic agents for managing diabetes and its complications.

Prohydrojasmon Promotes the Accumulation of Phenolic Compounds in Red Leaf Lettuce

Prohydrojasmon (PDJ) is a synthetic jasmonate derivative that is primarily used as a growth regulator, but its mechanism of action is unclear. In this study, we elucidated the effects of PDJ on phytochemical production in red leaf lettuce. The PDJ treatments promoted the accumulation of phenolic compounds in aerial plant parts. An LC-MS analysis revealed that these accumulated compounds were identified as cyanidin-3-O-glucoside, cyanidin-3-O-(6″-O-malonyl)-glucoside and cyanidin-3-O-(6″-O-malonyl)-glucoside methyl ester. The abundance of these compounds in lettuce extracts increased significantly in response to the PDJ treatment. Additionally, the LC-MS analysis also identified the accumulated phenolic compounds in the extracts of PDJ-treated lettuce, including caffeoyltartaric acid, chlorogenic acid, caffeoylmalic acid, chicoric acid, and dicaffeoylquinic acid. Gene expression analyses indicated the PDJ treatments upregulated the expression of PAL, F3H, and ANS genes in lettuce. These results suggest that PDJ treatments enhance the expression of genes involved in the synthesis of anthocyanins and phenolic compounds, resulting in an increase in the quantities of these compounds, which reportedly have various functions affecting human physiology.

3,5-Dicaffeoylquinic Acid Lowers 3T3-L1 Mitotic Clonal Expansion and Adipocyte Differentiation by Enhancing Heme Oxygenase-1 Expression

Adipogenesis is a complex process in which cell commitment and mitotic clonal expansion (MCE) are in-sequence crucial events leading to terminal adipocyte differentiation. The molecules able to block some key signals in this cascade can hamper adipogenesis becoming promising agents to counteract hyperplasia and hypertrophy of adipose tissue. Mono- and di-caffeoylquinic acid isomers are biologically active polyphenols, displaying in vitro and in vivo antioxidant, hepatoprotective, anti-diabetic and anti-obesity properties. Among these isomers, 3,5-dicaffeoylquinic acid (DCQA) has been reported to inhibit lipid accumulation in adipose cells more successfully than others. Thus, we investigated DCQA effects and molecular mechanisms on 3T3-L1 pre-adipocytes induced to differentiate with a hormonal cocktail (MDI). Oil Red O incorporation assessed that DCQA pre-treatment inhibited lipid accumulation in 3T3-L1 cells induced to differentiate for 10 days. At this time, an increased phosphorylation of both AMP-activated kinase and acetyl-CoA carboxylase, as well as a strong decrease in fatty acid synthase protein level, were registered by immunoblotting, thereby suggesting that DCQA treatment can reduce fatty acid anabolism in 3T3-L1 adipocytes. Furthermore, BrdU incorporation assay, performed 48 h after hormonal stimulation, revealed that DCQA treatment was also able to hinder the 3T3-L1 cell proliferation during the MCE, which is an essential step in the adipogenic process. Thus, we focused our attention on early signals triggered by the differentiation stimuli. In the first hours after hormonal cocktail administration, the activation of ERK1/2 and Akt kinases, or CREB and STAT3 transcription factors, was not affected by DCQA pre-treatment. Whereas 24 h after MDI induction, DCQA pre-treated cells showed increased level of the transcription factor Nrf2, that induced the expression of the antioxidant enzyme heme oxygenase 1 (HO-1). In control samples, the expression level of HO-1 was reduced 24 h after MDI induction in comparison with the higher amount of HO-1 protein found at 2 h. The HO-1 decrease was functional by allowing reactive oxygen species to boost and allowing cell proliferation induction at the beginning of MCE phase. Instead, in DCQA-treated cells the HO-1 expression was maintained at high levels for a further 24 h; in fact, its expression decreased only 48 h after MDI stimulation. The longer period in which HO-1 expression remained high led to a delay of the MCE phase, with a subsequent inhibition of both C/EBP-α expression and adipocyte terminal differentiation. In conclusion, DCQA counteracting an excessive adipose tissue expansion may become an attractive option in obesity treatment.

Effect-Directed Profiling of 17 Different Fortified Plant Extracts by High-Performance Thin-Layer Chromatography Combined with Six Planar Assays and High-Resolution Mass Spectrometry

An effect-directed profiling method was developed to investigate 17 different fortified plant extracts for potential benefits. Six planar effect-directed assays were piezoelectrically sprayed on the samples separated side-by-side by high-performance thin-layer chromatography. Multipotent compounds with antibacterial, α-glucosidase, β-glucosidase, AChE, tyrosinase and/or β-glucuronidase-inhibiting effects were detected in most fortified plant extracts. A comparatively high level of antimicrobial activity was observed for Eleutherococcus, hops, grape pomace, passiflora, rosemary and Eschscholzia. Except in red vine, black radish and horse tail, strong enzyme inhibiting compounds were also detected. Most plants with anti-α-glucosidase activity also inhibited β-glucosidase. Green tea, lemon balm and rosemary were identified as multipotent plants. Their multipotent compound zones were characterized by high-resolution mass spectrometry to be catechins, rosmarinic acid, chlorogenic acid and gallic acid. The results pointed to antibacterial and enzymatic effects that were not yet known for plants such as Eleutherococcus and for compounds such as cynaratriol and caffeine. The nontarget effect-directed profiling with multi-imaging is of high benefit for routine inspections, as it provides comprehensive information on the quality and safety of the plant extracts with respect to the global production chain. In this study, it not only confirmed what was expected, but also identified multipotent plants and compounds, and revealed new bioactivity effects.

Constituents from Solidago virgaurea var. gigantea and their inhibitory effect on lipid accumulation

In this study, the anti-adipogenic activities of compounds isolated from Solidago viraurea var. gigantea (SG) extracts were investigated using Oil Red O staining in the 3T3-L1 cell line. Four known compounds including 3,5-di-O-caffeoylquinic acid (5), protocatechuic acid (6), chlorogenic acid (7), and kaempferol-3-O-rutinoside (8), and four undescribed compounds including (1R,2S,3S,5R,7S)-methyl 7-((cinnamoyloxy)methyl)-2,3-dihydroxy-6,8-dioxabicyclo[3.2.1]octane-5-carboxylate (1), (1R,2S,3S,5R,7S)-methyl 2,3-dihydroxy-7-((((Z)-3-phenylacryloyl)oxy)methyl)-6,8-dioxabicyclo[3.2.1]octane-5-carboxylate (2), (1R,2S,3S,5R,7S)-2,3-dihydroxy-7-((((Z)-3-phenylacryloyl)oxy)methyl)-6,8-dioxabicyclo[3.2.1]octane-5-carboxylic acid (3), and (1R,2S,3S,5R,7S)-7-((cinnamoyloxy)methyl)-2,3-dihydroxy-6,8-dioxabicyclo[3.2.1]octane-5-carboxylic acid (4) were isolated from S. viraurea var. gigantea. The structures of the compounds were first identified by comparing their ¹H NMR spectra with spectral data from the literature and a more detailed identification was then performed using 2D NMR (Correlated spectroscopy (COSY), heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), and nuclear overhauser spectroscopy (NOESY)), and X-ray crystallography analyses. The anti-adipogenic activities of all compounds were evaluated by MTT assay and Oil Red O staining in 3T3-L1 cells. 3,5-di-O-caffeoylquinic acid was found to inhibit lipid accumulation more potently than the other tested compounds.

Systematic investigation of the mechanism of Cichorium glandulosum on type 2 diabetes mellitus accompanied with non-alcoholic fatty liver rats

Cichorium glandulosum(CG) can treat various diseases with multiple targets effectively. It has been widely used in folk medicine to treat nonalcoholic fatty liver disease (NAFLD) as well as type 2 diabetes mellitus (T2DM). However, the active compounds and underlying mechanisms of CG on T2DM accompanied with NAFLD (T2DM-NAFLD) remain unclear. In this study, a systems pharmacology method was used to explain the pharmacology mechanism of CG for treatment of T2DM-NAFLD. Twenty four main compounds were detected by UPLC-Q-TOF-MS, of which 13 showed favorable pharmacokinetic profiles. We demonstrated with target fishing and pathway analysis that CG has protective effects on T2DM-NAFLD, probably through the regulation of 88 targets and 86 pathways. Forty nine targets were related to T2DM, and 39 were related to NAFLD, while 27 targets, primarily involved in insulin resistance and inflammation were common to T2DM and NAFLD related pathways. A NF-κB signaling pathway was chosen to validate the impacts of CG on T2DM-NAFLD because CG can ameliorate T2DM-NAFLD by regulating the NF-κB signaling pathway according to animal experiments. These findings systematically interpreted the active compounds and mechanism of the efficiency of CG for treating T2DM-NAFLD. This study not only laid a basis for understanding the active compounds and action mechanism of CG, but also provides a reference for a study of the mechanism of a herbal medicine for the treatment of multiple diseases.

4,5-dicaffeyolquinic acid improves high-fat diet-induced cognitive dysfunction through the regulation of insulin degrading enzyme

This study was performed to investigate the effects of Artemisia argyi and 4,5-dicaffeyolquinic acid (4,5-diCQA) as a main compound of ethyl acetate fraction from Artemisia argyi (EFAA) on high-fat diet (HFD)-induced cognitive dysfunction. Both EFAA and 4,5-diCQA were effective in improving cognitive function on HFD-induced cognitive dysfunction. In brain tissue analysis, it was confirmed that EFAA and 4,5-diCQA inhibited the reduction of neurotransmitters as well as oxidative stress and mitochondrial dysfunction. In addition, they inhibited amyloid β (Aβ) accumulation by increasing the expression of insulin-degrading enzyme and consequently prevented apoptosis. In conclusion, it is presumed that Artemisia argyi may help to improve the cognitive impairment due to the HFD, and it is considered that this effect is closely related to the physiological activity of 4,5-diCQA. PRACTICAL APPLICATIONS: Artemisia argyi is used in traditional herbal medicine in Asia. Type 2 diabetes mellitus has been proven by a variety of epidemiological studies to be a risk factor for cognitive impairment, such as Alzheimer's disease. This study confirmed that 4,5-diCQA is a bioactive compound of Artemisia argyi on improving HFD-induced cognitive dysfunction. Therefore, this study can provide useful information to the effect of Artemisia argyi and related substance.

The protective effects of Cichorium glandulosum seed and cynarin against cyclophosphamide and its metabolite acrolein-induced hepatotoxicity in vivo and in vitro

Cyclophosphamide (CP) is a widely utilized chemotherapy drug. CP and its metabolite, acrolein, could induce hepatotoxicity. In this study, Cichorium glandulosum seed (CGS) effectively mitigated CP-induced hepatotoxicity in mice. Protection of cynarin, the major compound of CGS, against acrolein cytotoxicity in HepG2 cells was studied. Pretreatment with cynarin could improve cell survival against acrolein cytotoxicity. Cynarin restored the balance of glutathione (GSH) and reactive oxygen species (ROS), and inhibited mitochondrial depolarization. The kinetics of Nrf2 expression in cytosolic and nuclear fractions were observed after acrolein exposure. Intracellular Nrf2 expression was triggered within 6 h of exposure but did not translocate to the nucleus. Cynarin pretreatment ameliorated the expression and activity of GSH S-transferase and triggered Nrf2 nuclear translocation. In conclusion, treatment with CGS and cynarin protects liver injury against CP and acrolein hepatotoxicity via improvement of GSH activity and activation of the Nrf2 pathway.

Hydrolysis of Dicaffeoylquinic Acids from Ilex kudingcha Happens in the Colon by Intestinal Microbiota

Monocaffeoylquinic acids (mono-CQAs) can be hydrolyzed or metabolized by pancreatin, intestinal brush border esterase, and microbiota in the colon. Data about the conversion of dicaffeoylquinic acids (diCQAs) in digestion are scarce. The diCQA-rich fraction including 3,4-, 3,5-, and 4,5-diCQAs was prepared from Ilex kudingcha, and the conversion in simulated gastricintestine was investigated. Artificial saliva, gastric and pancreatic fluids, Caco-2 monolayer cells, and anaerobic fermentation model were utilized to mimic digestions of the oral cavity, stomach, small intestine, and colon in vitro. The results revealed that diCQAs remained intact in simulated saliva, gastric, and pancreatic fluids and within Caco-2 cells. In anaerobic fermentation with human fecal slurry, diCQAs were hydrolyzed to mono-CQAs and caffeic acid, which were further metabolized to caffeic acid and dihydrocaffeic acid, respectively. The hydrolysis of diCQAs depended on the chemical structures, carbohydrates in the culture medium, and microbial compositions. Our research demonstrated that hydrolysis of diCQAs happened in the colon by intestinal microbiota.