Chlorogenic acid, a polyphenolic compound, treats mice with septic arthritis caused by Candida albicans

Osteogenic mechanism of chlorogenic acid and its application in clinical practice

Natural polyphenols may have a role in counteracting oxidative stress, which is associated with aging and several bone-related diseases. Chlorogenic acid (CGA) is a naturally occurring polyphenolic compound formed by the esterification of caffeic and quininic acids with osteogenic, antioxidant, and anti-inflammatory properties. This review discusses the potential of CGA to enhance osteogenesis by increasing the osteogenic capacity of mesenchymal stem cells (MSCs), osteoblast survival, proliferation, differentiation, and mineralization, as well as its ability to attenuate osteoclastogenesis by enhancing osteoclast apoptosis and impeding osteoclast regeneration. CGA can be involved in bone remodeling by acting directly on pro-osteoclasts/osteoblasts or indirectly on osteoclasts by activating the nuclear factor kB (RANK)/RANK ligand (RANKL)/acting osteoprotegerin (OPG) system. Finally, we provide perspectives for using CGA to treat bone diseases.

Chlorogenic Acid Relieves the Lupus Erythematosus-like Skin Lesions and Arthritis in MRL/lpr Mice

Chlorogenic acid (CGA) is a phenylpropyl substance synthesized through the shikimic acid pathway. In addition to its anti-tumor, anti-inflammatory, and antioxidant abilities, CGA also has immunomodulatory effects. The aim of the present study is to investigate the therapeutic effects of CGA on the skin damage and arthritis caused by systemic lupus erythematosus (SLE) in an MRL/lpr mouse model. In the SLE model, female MRL/lpr mice at the age of 10 weeks old were treated with CGA daily or cyclophosphamide (CTX) weekly via intraperitoneal injection for three months. After treatment, CGA can significantly alleviate the skin and mucous membrane damage caused by SLE and has a certain improvement effect on arthritis. CGA could inhibit dsDNA expression to a certain extent but has no obvious regulation on ANA concentration. The ELISA and BioMAP results indicated that CGA might play an anti-inflammatory role by down-regulating the interleukin (IL)-17 level. In conclusion, our study demonstrates that CGA can alleviate multiorgan damage in MRL/lpr mice by reducing IL-17.

Antimicrobial, antioxidant and antileishmanial activities of Ziziphus lotus leaves

The aim of this study was to investigate antimicrobial and antioxidant activities of different fractions obtained from edible Tunisian Ziziphus Lotus leaves of Tozeur region. Different organic extracts were tested: cyclohexane, dichloromethane, ethyl acetate, n-butanol and water. Bio-guided fractionation revealed that dichloromethane fraction is the most active against S. aureus and Methicillin-resistant S. aureus strains. Moreover, this fraction showed the highest antileishmanial activity with IC₅₀ values of 20.55 ± 0.34 μg/mL and 15.37 ± 0.17 μg/mL against L. major and L. infantum, respectively. The potentialities of antibacterial and leishmanicidal activities found in dichloromethane could be explained by the presence of major flavonoids such as catechin, rutin and luteolin 7-O-glucoside as revealed by HPLC system. The observed moderate antifungal activity, which was only given by butanolic fraction against pathogen fungi, may be attributed to the presence of chlorogenic acid. Furthermore, dichloromethane and butanolic fraction showed a good DPPH (2,2-diphenyl-1-picryl hydrazyl) scavenging activity and Ferric reducing power. These results suggest that Ziziphus lotus leaf fractions might be used as antioxidant and antimicrobialagent.

The rationality involved in the popular use of coffee (Coffea sp) and sunflower seed (Helianthus annuus) for the treatment of vitiligo: a case report

INTRODUCTION

Vitiligo is a dermatological disease that affects about 0.38% to 2.9% of the world population. Currently, the main treatments used for vitiligo involve the use of topical drugs such as corticosteroids and calcineurin inhibitors, phototherapy, systemic treatment with steroids and even surgical grafts and, in acute cases, depigmenting treatments. Natural products are an alternative for the treatment of vitiligo: mamacadela (Brosimum gaudichaudii), a plant rich in furanocoumarins, and sowthistle (Sonchus oleraceus), rich in phenolic substances, are already used to treat vitiligo. There are also popular reports of the use of a preparation containing coffee (Coffea sp) and sunflower seed (Helianthus annuus) to treat vitiligo.

CASE REPORT

A female patient, 28 years old, diagnosed with vitiligo, reported having obtained a positive result in the repigmentation of the pale white patches after the daily use of a preparation containing coffee and sunflower seed for about one year.

DISCUSSION

Data from the scientific literature demonstrated that chemical constituents of these plants, such as chlorogenic acid and its isomers, which have antioxidant and anti-inflammatory action, and substances such as linoleic acid and vitamins E and B, which help in the process of melanin formation on the skin, may be responsible for the observed repigmentation of the patches. Further research on this case report is important for scientific validation and the development of new therapeutic options, especially with less adverse effects, in the treatment of vitiligo.

Chlorogenic acid ameliorated allergic rhinitis-related symptoms in mice by regulating Th17 cells

Allergic rhinitis (AR) is a non-infectious chronic inflammatory disease of nasal mucosa provoking T helper cell (Th) 17 response. Chlorogenic acid (CGA), one of the most abundant polyphenol compounds in various agricultural products, possesses antiviral, anti-inflammatory, and antibacterial properties. However, the effect of CGA on AR is unclear. Thus, our study explored the effect of CGA in modulating AR-related symptoms and immunoreaction, especially Th17 response. AR mice were induced by ovalbumin (OVA) administration and further treated with CGA or dexamethasone (Dex). The frequencies of rubbing and sneezing of AR mice were recorded. Histopathological analysis of nasal mucosa was conducted by Hematoxylin–Eosin and Periodic acid–Schiff stainings. The serum and nasal mucosa levels of OVA-immunoglobulin (Ig)E, interferon (IFN)-γ, retinoic acid-associated nuclear orphan receptor (ROR)-γt, and interleukin (IL)-17A were measured by enzyme-linked immunosorbent assay, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), or Western blot. The ratio of CD4⁺IL-17⁺Th17 cells to CD4⁺ T cells in peripheral blood of AR mice was assessed by flow cytometer. CGA diminished the frequencies of rubbing and sneezing of AR mice in a concentration-dependent manner. CGA attenuated histopathological abnormalities and decreased goblet cell number in nasal mucosa of AR mice. CGA decreased the serum levels of OVA-IgE, ROR-γt, and IL-17A, while increasing the serum level of IFN-γ in AR mice. Meanwhile, CGA decreased the ratio of CD4⁺IL-17⁺Th17 cells to CD4⁺T cells in peripheral blood and the mRNA and protein levels of IL-17A and ROR-γt in AR mice. CGA ameliorated AR-related symptoms in mice by regulating Th17 cells, which could be a candidate for the treatment of AR.

Study of the Variation of Phenolic Acid and Flavonoid Content from Fresh Artemisiae argyi Folium to Moxa Wool

Artemisiae argyi Folium (AAF) is a popular herbal medicine that is always employed in moxa sticks and by oral dosage in clinical use. Less attention has been paid to nonvolatile compounds as active compounds, such as phenolic acids and flavonoids. In this study, we focused on the variation rule of phenolic acids and flavonoids in the various transformations of Artemisiae argyi Folium. Using the established ultra-performance liquid chromatography (UPLC) method with an excellent methodology under “spider-web” mode, six phenolic acids and three flavonoids were simultaneously quantified in fresh and drying Artemisiae argyi Folium as well as in moxa wool and residue. Some interesting phenomena about the variation rule of phenolic acids and flavonoids were uncovered. First, a sharp increase was observed in the detected compounds’ content as the moisture gradually decreased, when fresh Artemisiae argyi Folium was exposed to sunlight and ambient or high temperature. Nevertheless, the increased phenolic acids were subjected to high temperature, leading to obvious degradation under oven-drying (60 °C and 80 °C). Second, a wide content distribution was revealed for the detected compounds in Artemisiae argyi Folium from different habitats, especially rutin, caffeic acid, chlorogenic acid, jaceosidin, eupatilin, and cryptochlorogenic acid. Third, accompanied by the elevated ratio of Artemisiae argyi Folium/moxa wool, the detected compounds conspicuously decreased in moxa wool and the correspondingly removed powder as residue. Importantly, a greater variation was found in moxa wool. Our findings contribute to the optimization of the drying process, the quality evaluation of the various transformations of Artemisiae argyi Folium, and the distinctive characterization of moxa wool produced at different ratios of Artemisiae argyi Folium/moxa wool.

Chlorogenic acid prevents inflammatory responses in IL‑1β‑stimulated human SW‑1353 chondrocytes, a model for osteoarthritis

Chlorogenic acid (CGA), which is a natural compound found in various plants, has been reported to exert notable anti‑inflammatory activities. The present study investigated the effects and underlying mechanism of CGA on interleukin (IL)‑1β‑induced osteoarthritis (OA) chondrocytes. An in vitro OA‑like chondrocyte model was established using IL‑1β‑stimulated human SW‑1353 chondrocytes. Cell viability was assessed using an MTT assay. Nitric oxide (NO) and IL‑6 production were evaluated by Griess reaction and ELISA, respectively. The expression levels of inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), cyclooxygenase 2 (COX‑2), collagen II, matrix metalloproteinase (MMP)‑13, p65 nuclear factor (NF)‑κB and inhibitor‑κBα were detected by western blot analysis. The results indicated that CGA reversed IL‑1β‑induced increases in iNOS/NO, IL‑6, MMP‑13 and COX‑2/PGE2 production, and reversed the IL‑1β‑mediated downregulation of collagen II. In addition, the data suggested that CGA was capable of inhibiting the IL‑1β‑induced inflammatory response, at least partially via the NF‑κB signaling pathway. In conclusion, CGA may be considered a suitable candidate agent in the treatment of OA.

Validation of the AlamarBlue® Assay as a Fast Screening Method to Determine the Antimicrobial Activity of Botanical Extracts

Plant compounds are a potential source of new antimicrobial molecules against a variety of infections. Plant extracts suppose complex phytochemical libraries that may be used for the first stages of the screening process for antimicrobials. However, their large variability and complexity require fast and inexpensive methods that allow a rapid and adequate screening for antimicrobial activity against a variety of bacteria and fungi. In this study, a multi-well plate assay using the AlamarBlue® fluorescent dye was applied to screen for antimicrobial activity of several botanical extracts and the data were correlated with microbial colony forming units (CFU). This correlation was performed for three pathogenic model microorganisms: Escherichia coli (Gram negative bacteria), Staphylococcus aureus (Gram positive bacteria) and for the yeast-like fungi Candida albicans. A total of ten plant extracts from different Mediterranean plants, including several Cistus and Hibiscus species, were successfully tested. HPLC-DAD-ESI-MS/MS analysis was utilized for the characterization of the extracts in order to establish structure-activity correlations. The results show that extracts enriched in ellagitannins and flavonols are promising antibacterial agents against both Gram positive and Gram negative bacteria. In contrast, phenolic acids, anthocyanidins and flavonols may be related to the observed antifungal activity.

Antifungal effects of phytocompounds on Candida species alone and in combination with fluconazole

Invasive fungal infections caused by Candida spp. remain the most predominant nosocomial fungal infections. Owing to the increased use of antifungal agents, resistance of Candida spp. to antimycotics has emerged frequently, especially to fluconazole (FLC). To cope with this issue, new efforts have been dedicated to discovering novel antimycotics or new agents that can enhance the susceptibility of Candida spp. to existing antimycotics. The secondary metabolites of plants represent a large library of compounds that are important sources for new drugs or compounds suitable for further modification. Research on the anti-Candida activities of phytocompounds has been carried out in recent years and the results showed that a series of phytocompounds have anti-Candida properties, such as phenylpropanoids, flavonoids, terpenoids and alkaloids. Among these phytocompounds, some displayed potent antifungal activity, with minimum inhibitory concentrations (MICs) of ≤8 µg/mL, and several compounds were even more effective against drug-resistant Candida spp. than FLC or itraconazole (e.g. honokiol, magnolol and shikonin). Interestingly, quite a few phytocompounds not only displayed anti-Candida activity alone but also synergised with FLC against Candida spp., even leading to a reversal of FLC resistance. This review focuses on summarising the anti-Candida activities of phytocompounds as well as the interactions of phytocompounds with FLC. In addition, we briefly overview the synergistic mechanisms and present the structure of the antimycotic phytocompounds. Hopefully, this analysis will provide insight into antifungal agent discovery and new approaches against antifungal drug resistance.

Phytochemical Composition, Antifungal and Antioxidant Activity of Duguetia furfuracea A. St.-Hill

Background. Duguetia furfuracea is popular plant used in popular medicine. Hypothesis/Purpose. This claim evaluated the phytochemical composition of the hydroethanolic extract (HEDF), fractions of Duguetia furfuracea, and antioxidant and antifungal activity. Methods. The chemical profile was carried out by HPLC-DAD. The total phenolic contents and flavonoid components were determined by Folin-Ciocalteu and aluminium chloride reaction. The antioxidant activity was measured by scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and ferric reducing ability of plasma (FRAP) methods. The antifungal activity was determined by microdilution assay. Results. HPLC analysis revealed caffeic acid and rutin as major compounds (HEDF), caffeic acid and quercitrin (Mt-OH fraction), and quercitrin and isoquercitrin (Ac-OEt fraction). The highest levels of phenols and total flavonoids were found for Ac-OEt fraction, and the crude extract showed higher in vitro antioxidant potential. The antifungal activity showed synergic effect with fluconazole and EHDF against C. krusei, fluconazole and Mt-OH against C. krusei and C. tropicalis, and Ac-OE and fluconazole against C. albicans. Conclusion. The highest levels of phenols and total flavonoids were marked with antioxidant effect. This is the first report of bioactivity of the synergic effect of HEDF and fractions. More studies would be required to better clarify its mechanism of synergic action.

Evidence for anti-inflammatory and antioxidative properties of dried plum polyphenols in macrophage RAW 264.7 cells

This study presents the anti-inflammatory and antioxidative properties of dried plum (Prunus domestica L.) polyphenols in macrophage RAW 264.7 cells. We hypothesized that dried plum polyphenols have strong anti-inflammatory and antioxidant properties against lipopolysaccharide (LPS)-induced production of the pro-inflammatory markers, nitric oxide (NO) and cyclooxygenase-2 (COX-2), and the lipid peroxidation product, malondialdehyde, in activated macrophage RAW 264.7 cells. To test this hypothesis, macrophage RAW 264.7 cells were stimulated with either 1 μg ml(-1) (for measurement of NO production) or 1 ng ml(-1) (for measurement of COX-2 expression) of LPS to induce inflammation and were treated with different doses of dried plum polyphenols (0.0, 0.1, 1, 10, 100 and 1000 μg ml(-1)). Dried plum polyphenols at a dose of 1000 μg ml(-1) was able to significantly (P < 0.05) reduce NO production by 43%. Additionally, LPS-induced expression of COX-2 was significantly (P < 0.05) reduced by 100 and 1000 μg ml(-1) dried plum polyphenols. To investigate the antioxidant activity of dried plum polyphenols, macrophage RAW 264.7 cells were stimulated with 100 μg ml(-1) of FeSO4 + 1 mM ml(-1) of H2O2 to induce lipid peroxidation. Dried plum polyphenols at a dose of 1000 μg ml(-1) showed a 32% reduction in malondialdehyde production. These findings indicate that dried plum polyphenols are potent anti-inflammatory and antioxidative agents in vitro.

HPLC Analysis, Optimization of Extraction Conditions and Biological Evaluation of Corylopsis coreana Uyeki Flos

A method for the separation and quantification of three flavonoids and one isocoumarin by reverse-phase high performance liquid chromatography (HPLC) has been developed and validated. Four constituents present in a crude ethanolic extract of the flowers of Coryloposis coreana Uyeki, were analyzed. Bergenin, quercetin, quercitrin and isosalipurposide were used as calibration standards. In the present study, an excellent linearity was obtained with an r² higher than 0.999. The chromatographic peaks showed good resolution. In combination with other validation data, including precision, specificity, and accuracy, this method demonstrated good reliability and sensitivity, and can be conveniently used for the quantification of bergenin, quercetin, quercitrin and isosalipurposide in the crude ethanolic extract of C. coreana Uyeki flos. Furthermore, the plant extracts were analyzed with HPLC to determine the four constituents and compositional differences in the extracts obtained under different extraction conditions. Several extracts of them which was dependent on the ethanol percentage of solvent were also analyzed for their antimicrobial and antioxidant activities. One hundred % ethanolic extract from C. coreana Uyeki flos showed the best antimicrobial activity against the methicillin-resistant Staphylococcus aureus (MRSA) strain. Eighty % ethanolic extract showed the best antioxidant activity and phenolic content. Taken of all, these results suggest that the flower of C. coreana Uyeki flos may be a useful source for the cure and/or prevention of septic arthritis, and the validated method was useful for the quality control of C. coreana Uyeki.

Anti-arthritic activity of Fu-Fang-Lu-Jiao-Shuang on collagen-induced arthritis in Balb/c mice and its underlying mechanisms

Background:

Rheumatoid arthritis (RA) is a common, autoimmune disorder characterized by progressive multiple joint destruction, deformity, disability and premature death in most patients. Fu-Fang-Lu-Jiao-Shuang (FFLJS) is an effective traditional Chinese medicine, which has long been used clinically to treat RA patients.

Objective:

The objective of this study is aimed to evaluate the anti-rheumatic effects of FFLJS on collagen induced arthritis (CIA) model, as well as the underlying mechanisms, which have not previously been explored.

Materials and Methods:

CIA was induced by immunization with type II collagen (CII) in male Balb/c mice. The mice in the onset of arthritis were treated daily with FFLJS (125 or 500 mg/kg) or 1% carboxymethyl cellulose-Na for 28 days. Paw thickness and arthritic score were evaluated to confirm the anti-arthritic effect of FFLJS on CIA in mice. Levels of anti-CII antibody, proinflammatory cytokines interleukin-1 (IL-1) β, IL-17, and tumor necrosis factor-α (TNF-α) as well as prostaglandin E-2 (PGE-2) in serum and histological changes in the ankle joint were also analyzed. In addition, expressions of matrix metalloproteinases-1 (MMP-1), MMP-3 and tissue inhibitors of matrix metalloproteases-1 (TIMP-1) in synovial tissue were also detected to further study the molecular mechanism of the anti-arthritic effects of FFLJS.

Results:

During therapeutic treatment, FFLJS significantly reduced paw thickness and arthritic score in CIA mice, decreased the amounts of TNF-α, IL-1 β, IL-17, PGE-2 and anti-CII antibody in serum. In addition, FFLJS treatment could prevent the bone destruction by reducing the expression of MMP-1 and MMP-3, increasing the expression of TIMP-1 in synovial tissue of CIA mice.

Conclusion:

These findings offer the convincing evidence for the first time that the anti-rheumatic effects of FFLJS might be related to down-regulation of TNF-α, IL-1 β, IL-17 and PGE-2 levels for acute arthritis, and regulation of MMP-1, MMP-3 and TIMP-1 protein expression for chronic arthritis.

Tetrachlorobenzoquinone induces acute liver injury, up-regulates HO-1 and NQO1 expression in mice model: the protective role of chlorogenic acid

Tetrachlorobenzoquinone (TCBQ) is an active metabolite of pentachlorophenol (PCP). Although PCP has been investigated extensively, there are only a few reports describing the toxicity effect of TCBQ, and no report regarding TCBQ-induced liver injury in vivo. In the current study, we aimed to examine the acute hepatic toxicity of TCBQ in the mice model. Chlorogenic acid (CGA) exhibits promising antioxidant activity in the past studies, thus, the second aim of this study was to evaluate the protective effect of CGA on TCBQ-induced liver injury. Our results indicated TCBQ-intoxication caused marked liver cell necrosis and inflammation but not apoptosis, and this damage was alleviated by CGA treatment. Meantime, TCBQ-intoxication enhanced serum ALT, AST activities, TBIL content, hepatic oxidative stress and lipid peroxidation, decreased GSH content and inhibited the activities of antioxidant enzymes. Western blot and immunohistochemical analysis showed that TCBQ marked up-regulated HO-1 and NQO1 expression. On the other hand, pretreatment of CGA reduced TCBQ-induced liver damage remarkably. Taking together, these results revealed that TCBQ has strong hepatic toxic effect, and at least a part of this effect is initiated by free radical and relieved with CGA administration.

An outlook on chlorogenic acids-occurrence, chemistry, technology, and biological activities

Phenolics are widespread dietary antioxidants. Among these, chlorogenic acids (CGAs) received considerable attention for their wide distribution and part of human diet with potential biological effects. CGAs (71 compounds), being esters of derivatives of cinnamic acids with quinic acid are widely distributed in plant materials. Coffee is among the highest found in plants, ranging from 4 to 14%. Besides, these are reported in plant foods such as apples, pears, carrot, tomato, sweet potato, Phyllostachys edulis, oilseeds, Prunus domestica L, cherries, and eggplant. The traditional Chinese medicinal plants such as flowers and buds of Lonicera japonica Thunb and the leaves of Eucommia ulmodies contained CGAs as bioactive compound. These play an important role in the formation of roasted coffee flavor and have a marked influence on coffee cup quality. CGAs are considered as main precursors of coffee flavor and pigments. Recent technological advancements in the separation and purification of CGAs such as molecular-imprinted polymer technique; microwave-assisted extraction; pH gradient counter current chromatography has also been described. The consumption of coffee correlated to several health benefits such as reducing the risk of human chronic diseases such as inflammation, diabetes, and cardiovascular disease owing to its antioxidant potential.

WIN-34B May Have Analgesic and Anti-Inflammatory Effects by Reducing the Production of Pro-Inflammatory Mediators in Cells via Inhibition of IκB Signaling Pathways

WIN-34B showed analgesic and anti-inflammatory effects in various animal models of pain and osteoarthritis. However, the molecular mechanism by which WIN-34B inhibits pain and inflammation in vivo remains to be elucidated. We investigated the molecular mechanisms of the actions of WIN-34B using various in vitro models using fibroblast-like synoviocytes from patients with rheumatoid arthritis (RA FLSs), RAW264.7 cells and peritoneal macrophages. WIN-34B inhibited the level of IL-6, PGE₂, and MMP-13 in IL-1β-stimulated RA FLSs in a dose-dependent manner. The mRNA levels were also inhibited by WIN-34B. The level of PGE₂, NO, IL-1β, and TNF-α were inhibited by WIN-34B at different concentrations in LPS-stimulated RAW264.7 cells. The production of NO and PGE₂ was inhibited by WIN-34B in a dose-dependent manner in LPS-stimulated peritoneal macrophages. All of these effects were comparable to the positive control, celecoxib or indomethacin. IκB signaling pathways were inhibited by WIN-34B, and the migration of NF-κB into the nucleus was inhibited, which is consistent with the degradation of IκB-α. Taken together, the results suggest that WIN-34B has potential as a therapeutic drug to reduce pain and inflammation by inhibiting the production of pro-inflammatory mediators.

Ginsenoside Rd induces protective anti-Candida albicans antibody through immunological adjuvant activity

The role of an antibody against candidiasis is controversial. However, a certain Candida albicans surface epitope produces a protective antibody. Yet, its isolation is difficult. In this study, we investigated if ginsenoside Rd from Panax ginseng has an immunoadjuvant ability to induce surface mannan extract (CASM) to produce a protective antibody. Mice were immunized twice i.p. with an emulsion form of CASM mixed with one of the following: IFA [CASM/IFA], or CFA [CASM/CFA] or Rd with IFA [CASM/Rd/IFA]. One week after the booster, these mice were challenged i.v. with live C. albicans and their survivability was measured. Results showed that four of five CASM/Rd/IFA-vaccinated mice survived during the entire 110 day-observation period, whereas CASM/IFA- or CASM/CFA-vaccinated mice died within 19 and 23 days (P<0.05). The antiserum from CASM/Rd/IFA-immunized mice transferred the protection to naïve mice, whereas antiserum from CASM/CFA-given mice was not protective although CASM/CFA induced an antibody four times greater than CASM/Rd/IFA. IgG isotyping revealed that CASM/Rd/IFA-vaccine produced the most abundant IgG and IgG2a-resulting in the highest ratio (1.32) of IgG2a to IgG, which is helpful in treating Th2-oriented candidiasis. In contrast, the formulae lacking Rd had these ratios less than 1. This strongly indicates that Rd could enhance Th1 immunity. Cytokine profiles and DTH further confirmed the Th1 dominance. Rd caused no hemolysis. Combining all of these data together, Rd can enhance Th1-response to CASM in mice. This protects mice against disseminated candidiasis by eliciting higher titers of Th1 type antibody and a Th1-dominant immune response.

18β-glycyrrhetinic acid induces immunological adjuvant activity of Th1 against Candida albicans surface mannan extract

The aim of this study was to determine the immunological adjuvant effect of 18β-glycyrrhetinic acid (GA) isolated from Glycyrrhizae radix. In the experiments, BALB/c mice were immunized on days 1 and 22 intraperitoneally (i.p.) with an emulsion form of Candida albicans surface mannan extract (SM) mixed with either Incomplete Freund's Adjuvant [SM/IFA], or Complete Freund's Adjuvant [SM/CFA] or GA mixed with IFA [SM/GA/IFA]. One week after the second immunization, polyclonal sera were collected from these animals in order to determine IgG isotypes and cytokine profiles in the sera. After the collection, the spleen samples were collected to determine the degree of T cell proliferation. Additionally, the DTH (delayed type hypersensitivity) response was examined by measuring the footpad swelling of immunized mice. Data resulting from the T cell proliferation test showed that SM/GA/IFA enhanced the proliferation the most. The enhancement was about 85% more compared to SM/IFA (p<0.05). IgG isotypes and cytokine profiles displayed that SM/GA/IFA induced the most abundant production of total IgG with the highest IgG2a/IgG1 ratio (1.31) and greatest IFN-γ secretion. In contrast, SM/CFA resulted in an IgG2a/IgG1 ratio less than 1 and SM/IFA produced a dominant induction of IL-4, but almost no IFN-γ secretion. Together, these observations revealed that GA developed a greater Th1 immune response than Th2 response. The DTH determination confirmed that GA-addition induced dominant Th1 immunity - displaying the highest footpad-swelling followed by SM/CFA and BSA/IFA, respectively. All of this data indicates that GA has a Th1-immunological adjuvant activity, which would be beneficial in the treatment of Th1-disordered disease due to C. albicans.

Evaluation of the potential sensitization of chlorogenic Acid: a meta-analysis

Chlorogenic acid (CGA) widely exists in many plants, which are used as medicinal substances in traditional Chinese medicine injectables (TCMIs) that have been widely applied in clinical treatments. However, it is still controversial whether CGA is responsible for TCMIs-related hypersensitivity. Several studies have been performed to evaluate its potential sensitization property, but the results were inconclusive. Therefore, the aim of this study was to evaluate its potential sensitization systematically using meta-analysis based on data extracted from literatures, searching databases of PubMed, EMBASE, ISI Web of Knowledge, CNKI, VIP, and CHINAINFO from January 1979 to October 2012, a total of 108 articles were retrieved by electronic search strategy, out of which 13 studies met the inclusion criteria. In ASA test, odds ratio of behavior changes was 4.33 (1.62, 11.60), showing significant changes after CGA treatment (P = 0.004). Serum IgG, serum histamine, PLN cellularity, and IgG1 AFCs were significantly enhanced after CGA treatment (P < 0.05). Totally, these results indicated that CGA could induce a positive reaction in potential sensitization, and intravenous administration of it might be a key factor for sensitization triggering, which could at least warrant more careful application of TCMIs containing CGA in clinical practices.

Chlorogenic acid decreases retinal vascular hyperpermeability in diabetic rat model

To evaluate the effect of chlorogenic acid (CGA), a polyphenol abundant in coffee, on retinal vascular leakage in the rat model of diabetic retinopathy, Sprague-Dawley rats were divided into four groups: controls, streptozotocin-induced diabetic rats, and diabetic rats treated with 10 and 20 mg/kg chlorogenic acid intraperitoneally daily for 14 days, respectively. Blood-retinal barrier (BRB) breakdown was evaluated using FITC-dextran. Vascular endothelial growth factor (VEGF) distribution and expression level was evaluated with immunohistochemistry and Western blot analysis. Expression of tight junction proteins, occludin and claudin-5, and zonula occludens protein, ZO-1 was also evaluated with immunohistochemistry and Western blot analysis. BRB breakdown and increased vascular leakage was found in diabetic rats, with increased VEGF expression and down-regulation of occludin, claudin-5, and ZO-1. CGA treatment effectively preserved the expression of occludin, and decreased VEGF levels, leading to less BRB breakdown and less vascular leakage. CGA may have a preventive role in BRB breakdown in diabetic retinopathy by preserving tight junction protein levels and low VEGF levels.

Structure-activity differences of chlorogenic acid and its isomers on sensitization via intravenous exposure

Chlorogenic acid (CGA) is found in many plants that are used as medicinal substances in traditional Chinese medicine injectables (TCMIs). However, to date, there is controversy as to whether CGA is the major cause of TCMIs-related hypersensitivity administered intravenously. Therefore, the aim of this study was to evaluate the potential sensitization of CGA and structure-activity differences between its isomers using an intravenous exposure mouse model. The results showed that popliteal lymph nodes proliferation was significantly induced by CGA and its isomers. Both CGA and isochlorogenic acid A (iso-CGA A) significantly enhanced the secretion of trinitrophenyl (TNP) ovalbumin-specific immunoglobulin (Ig)G1; and iso-CGA B significantly induced TNP-specific IgG1, IgM, and IgG2b secreting. Furthermore, the results of quantitative structure-activity relationship analysis suggested that chemical structure factors, including atomic mass, electronegativity, atom shape and size, atom distribution, atomic weight, and atomic polarizabilities, the ionic currents, were significantly correlated with the potential sensitization of CGA and its isomers. In summary, when administered intravenously, the strength and type of sensitization may be correlated with structure differences in the CGA family.

Immunoadjuvant activity of icariin that induces Th1-type antibody in mice

The adjuvant effect of icariin from Epimedium koreanum on the immune responses to bovine serum albumin (BSA) in mice was examined. Mice were immunized on days 1 and 22 intraperitoneally (i.p.) with one of the following: an emulsion form of BSA mixed with Incomplete Freund's Adjuvant (BSA/IFA) or with Complete Freund's Adjuvant (BSA/CFA) or BSA plus icariin mixed with IFA (BSA/Icariin/IFA). One week after the booster, polyclonal sera were collected from these animals to determine IgG isotypes specific for BSA in the sera and then spleens of these animals were harvested to evaluate IFN-γ and IL-4 produced in the splenocyte cultures. In order to determine the DTH (delayed type hypersensitivity) response, BSA was administered into the footpads of mice that were immunized as described above and the degree of footpad-swelling was measured. Data from these experiments showed that the icariin combined with BSA (BSA/Icariin/IFA) provoked the most abundant of IgG production in mice and enhanced the Th1-lineage development of IgG2a and IFN-γ productions (p < 0.05), whereas BSA/IFA resulted in a highest ratio of IgG1 to IgG2 and most dominant IL-4 production, indicating a Th2 response. This pattern of immunity was confirmed by the DTH determination revealing that icariin-containing formula caused the highest footpad-swelling followed by BSA/CFA and BSA/IFA, respectively. In addition, hemolytic assay showed that icariin at a dose of 1000 μg/mL caused no hemolysis when compared with a water-treated mouse. All of these data indicate that icariin has the immunoadjuvant effect which may enhance Th1-immune response, suggesting that icariin as an adjuvant would be beneficial in the treatment of Th1-disordered diseases.

Chlorogenic acid inhibits LPS-induced microglial activation and improves survival of dopaminergic neurons

Pro-inflammatory factors released by activated microglia may contribute to the progression of neurodegenerative diseases. As a natural phenolic acid, chlorogenic acid (CGA) has been shown to have anti-inflammatory properties. However, it is unclear whether CGA has the ability to mediate microglial activation. The present study investigated the role of CGA in lipopolysaccharide (LPS)-stimulated microglia. Our data demonstrated that CGA significantly suppressed NO production and TNF-α release in LPS-stimulated primary microglia. In addition, CGA decreased LPS-stimulated phosphorylation and degradation of inhibitory kappa B-alpha (IκBα), and prevented translocation of nuclear factor-kappaB (NF-κB). Furthermore, CGA prevented neurotoxicity caused by microglial activation and ultimately improved survival of dopaminergic (DA) neuron. Finally, in vivo data showed that CGA pretreatment attenuated LPS-induced IL-1β and TNF-α release in substantia nigra (SN). Our results suggested that the pretreatment of CGA significantly inhibits the microglial activation, and CGA may be neuroprotective for pro-inflammatory factor-mediated neurodegenerative disorders.

Chlorogenic acid protects mice against lipopolysaccharide-induced acute lung injury

Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in human diet. Our previous in vitro study demonstrates that CGA presents anti-inflammatory activities in RAW 264.7 cells. Here we show that CGA protects mice against lipopolysaccharide (LPS)-induced acute lung injury (ALI). We treated mice with CGA (5, 20 and 50 mg/kg body weight) 30 min or 3 h after intratracheal administration of LPS. The histological results showed that CGA, at dose of 50 mg/kg, protected mice from LPS-induced ALI which displayed by edema, haemorrhage, blood vessel and alveolar structural damage. CGA inhibited LPS-increased pulmonary MPO activity and migration of polymorphonuclear neutrophils (PMNs) into bronchoalveolar lavage fluid (BALF). Furthermore, CGA markedly decreased the activity of inducible nitric oxide synthase (iNOS) in lung tissues and thus prevented nitric oxide (NO) release in response to LPS challenge. In conclusion, these results indicated that CGA was greatly effective in inhibiting ALI and might act as a potential therapeutic reagent for treating ALI in the future.