Activation of mitogen-activated protein kinases and AP-1 by polysaccharide isolated from the radix of Platycodon grandiflorum in RAW 264.7 cells

Polysaccharides from Platycodon grandiflorum: A review of their extraction, structures, modifications, and bioactivities

Platycodon grandiflorum (P. grandiflorum) has long been used as a food and traditional herbal medicine. As a food, P. grandiflorum is often transformed into pickles for consumption, and as a traditional Chinese medicine, P. grandiflorum clears the lung, nourishes the pharynx, dispels phlegm, and discharges pus. Polysaccharides are among the main active components of P. grandiflorum. Recent literature has described the preparation, identification, and pharmacological activity of these polysaccharides. Studies have shown that these polysaccharides exhibit a variety of significant biological effects in vitro and in vivo, such as immune stimulation and antioxidant, anti-liver injury, anti-apoptosis and antitumour effects. However, there is no systematic summary of the related research articles on P. grandiflorum polysaccharide, which undoubtedly brings some difficulties to the future research. The purpose of this review is to comprehensively describe research progress on the extraction, purification, structural characterization, modification, and biological activity of P. grandiflorum polysaccharides. The shortcomings of recent research are summarized, further research on their biological activity is proposed to provide new reference value for the application of P. grandiflorum polysaccharides in drugs and health products in the future.

In vitro immune-enhancing effects of Platycodon grandiflorum combined with Salvia plebeian via MAPK and NF-κB signaling in RAW264.7 cells

The immune-enhancing activity of the combination of Platycodon grandiflorum and Salvia plebeian extracts (PGSP) was evaluated through macrophage activation using RAW264.7 cells. PGSP (250-1000 μg/mL) showed a higher release of NO in a dose-dependent manner. The results showed that PGSP could significantly stimulate the production of PGE2, COX-2, TNF-α, IL-1β, and IL-6 in RAW264.7 cells and promote iNOS, COX-2, TNF-α, IL-1β, IL-4, and IL-6 mRNA expression. Western blot analysis demonstrated that the protein expression of iNOS and COX-2 and the phosphorylation of ERK, JNK, p38, and NF-κB p65 were greatly increased in PGSP-treated cells. PGSP also promoted the phagocytic activity of RAW264.7 cells. All these results indicated that PGSP might activate macrophages through MAPK and NF-κB signaling pathways. Taken together, PGSP may be considered to have immune-enhancing activity and might be used as a potential immune-enhancing agent.

Preparation methods, structural characteristics, and biological activity of polysaccharides from Platycodon grandiflorus

Platycodon grandiflorus (P. grandiflorus), a traditional Chinese medicinal herb used for both medicine and food, has a long history of treating respiratory infections, bronchitis, pneumonia, and other lung-related diseases. The therapeutic effects of P. grandiflorus are attributed to its chemical components, including polysaccharides. Among these components, Platycodon grandiflorus polysaccharides (PGP) are recognized as one of the most important and abundant active ingredients, exhibiting various biological activities such as prebiotic, antioxidant, antiviral, anticancer, antiangiogenic, and immune regulatory properties. Incorporating the principles of traditional Chinese medicine, carrier concepts, and modern targeted drug delivery technologies, PGP can influence the target sites and therapeutic effects of other drugs while also serving as a drug carrier for targeted and precise treatments. Therefore, it is essential to provide a comprehensive review of the extraction, separation, purification, physicochemical properties, and biological activities of PGP. In the future, by integrating new concepts, technologies, and processes, further references and guidance can be provided for the comprehensive development of PGP. This will contribute to the advancement of P. grandiflorus in various fields such as pharmaceuticals, health products, and food.

Recent advances in Platycodon grandiflorum polysaccharides: Preparation techniques, structural features, and bioactivities

Platycodon grandiflorum, a globally recognized medicinal and edible plant, possesses significant nutritional value and pharmacological value. In traditional Chinese medicine, it has the effects of tonifying the spleen and replenishing the Qi, moistening the lung and relieving the cough, clearing the heat and detoxifying, and relieving the pain. Accumulating evidence has revealed that the polysaccharides from P. grandiflorum (PGPs) are one of the major and representative biologically active macromolecules and have diverse biological activities, such as immunomodulatory activity, anti-inflammatory activity, anti-tumor activity, regulation of the gut microbiota, anti-oxidant activity, anti-apoptosis activity, anti-angiogenesis activity, hypoglycemic activity, anti-microbial activity, and so on. Although the polysaccharides extracted from P. grandiflorum have been extensively studied for the extraction and purification methods, structural characteristics, and pharmacological activities, the knowledge of their structures and bioactivity relationship, toxicologic effects, and pharmacokinetic profile is limited. The main purpose of the present review is to provide comprehensively and systematically reorganized information on extraction and purification, structure characterizations, and biological functions as well as toxicities of PGPs to support their therapeutic potentials and sanitarian functions. New valuable insights for future research regarding PGPs were also proposed in the fields of therapeutic agents and functional foods.

Structure, selenization modification, and antitumor activity of a glucomannan from Platycodon grandiflorum

Platycodon grandiflorum is consumed popularly as a nutritional and healthy plant in East Asia, which has multiple medicinal functions. As an exploration to elucidate the beneficial ingredients, an acetylated glucomannan (PGP40-1) was purified from P. grandiflorum. Structural analysis showed that PGP40-1 was composed of →4)-β-Manp-(1→, →4)-β-Glcp-(1→, →6)-β-Glcp-(1→, and terminal α-Glcp-(1→. PGP40-1 was found to possess weak antitumor activity in vitro, which was thus modified to afford a selenized polysaccharide (Se-PGP40-1) by the HNO₃/Na₂SeO₃ method. Se-PGP40-1 showed significant antitumor activity in cell and zebrafish models, which could inhibit tumor proliferation and migration by inducing cell apoptosis and blocking angiogenesis. The research not only clarifies the ingredients of P. grandiflorum with high economical value, but also affords a potential antitumor agent originating from the plant polysaccharide.

Platycodon grandiflorus polysaccharides deeply participate in the anti-chronic bronchitis effects of platycodon grandiflorus decoction, a representative of “the lung and intestine are related”

Platycodon grandiflorus (Jacq.) A. DC. (PG) root is one of the most commonly used medicine-food materials for respiratory discomfort in Asia, usually in the form of a decoction or leaching solution. As everyone knows, both of decoction and leaching solution is a polyphase dispersion system, containing low-molecular-weight water-soluble active ingredients and hydrophilic macromolecules. This study aimed to discuss the synergistic effect of Platycodon grandiflorus polysaccharide (PGP) and platycodin D (PD) in PG decoction against chronic bronchitis (CB) and the mechanism underlying. A series of PGP, PD, and PGD + PD suspensions were administrated to CB model rats, on the levels of whole animal and in situ intestinal segment with or without mesenteric lymphatic vessels ligation. It exhibited that PGP exhibited synergistic effects with PD, on improving the histopathological abnormity, mucus secretion excess, and immunological imbalance in lung of CB model rat, closely associated with its modulations on the mucosal immunity status in small intestine. The polysaccharide macromolecules in PG decoction or leaching solution should be responsible for the modulation of pulmonary immune state, possibly through the common mucosal immune between small intestine and lung. These results might be a new perspective that illustrates the classical theory of “the lung and intestine are related” in traditional Chinese medicine.

Polysaccharide extracted from Taraxacum platycarpum root exerts immunomodulatory activity via MAPK and NF-κB pathways in RAW264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum platycarpum Dahlst. (Korean dandelion) is a medicinal herb used in traditional medicine in Korea to treat various disease such as furuncles, mammitis, hepatitis, jaundice. Moreover, a decoction prepared from T. platycarpum leaves and stems is an effective treatment for cancer, glycosuria, liver disease, pleurodynia, and stomach problems.

AIM OF THE STUDY

The main objective of this work was to study the composition and structural properties of polysaccharides (TPP) from Taraxacum platycarpum Dahlst. root and investigate the immunostimulatory activity on RAW264.7 cells.

MATERIALS AND METHODS

TPP was extracted from T. platycarpum using hot water extraction, ethanol precipitation method and its fractionated using DEAE-Sepharose fast flow column. The composition, molecular weight, and structural characterization of TPP and its fractions were evaluated by various techniques. Further, the immunostimulatory activity of polysaccharides was tested on murine macrophage cell line RAW264.7 by various in vitro assays. The structure effect of TPP on RAW264.7 cells was studied by the removal of sulfate (desulfation) and protein (deproteinization) contents from TPP.

RESULTS

We obtained three fractions namely TPP-1, TPP-2, and TPP-3 which mainly consisted of carbohydrates (75.55, 52.71, and 48.41%), sulfate (8.42, 15.19, and 27.67%), uronic acid (1.27, 6.56, and 4.39%), and protein (8.15, 24.85, and 9.73%). The average molecular weight of the fractions was 56.7, 108.2, and 132.3 × 10³ g/mol, respectively. The polysaccharides activate the RAW264.7 cell to produce a significant amount of NO and upregulate the various mRNA expression by the activation of MAPK and NF-κB pathways via TLR4, TLR2, and CR3 receptors. The structurally modified deproteinated derivative (DP-TPP-2) more effectively decreases the NO production which means the protein content of TPP-2 mainly contributes to the RAW264.7 cells activation. The structure of DP-TPP-2 primarily consists of 1 → 2)-Galp, 1 → 6)-Glup, 1 → 2) - Rhap, and 1 → 5) - Arap glycosidic linkages.

CONCLUSIONS

The present study demonstrated that the polysaccharide isolated from T. platycarpum shows admirable immunostimulatory by the activation of MAPK and NF-κB pathways through TLR4, TLR2, and CR3 receptors. The protein content of polysaccharides mainly contributes to the RAW264.7 cells activation. Our study results could be useful for developing a new immunostimulant agent.

Safety evaluation of fermented Platycodon grandiflorus (Jacq.) A.DC. extract: Genotoxicity, acute toxicity, and 13-week subchronic toxicity study in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Platycodon grandiflorus (Jacq.) A.DC. is a well-known traditional herbal medicine administered for bronchitis and inflammatory diseases. Especially, anti-inflammatory effect of fermented P. grandiflorus (Jacq.) A.DC. extract (FPGE) was higher than that of P. grandiflorus (Jacq.) A.DC. extract. However, toxicological information for FPGE is lacking.

AIM OF THE STUDY

In this study, we establish a toxicological profile for FPGE by testing genotoxicity, acute and 13-week subchronic toxicity.

MATERIALS AND METHODS

FPGE was evaluated with bacterial reverse mutation, chromosome aberration, and micronucleus test. For the acute- and 13-week subchronic toxicity tests, FPGE was administered orally at doses of 0, 750, 1500, and 3000 mg/kg in SD rats.

RESULTS

The results of the genotoxic assays indicated that FPGE induced neither mutagenicity nor clastogenicity. The acute toxicity test showed that FPGE did not affect animal mortality, clinical signs, body weight changes, or microscopic findings at ≤ 3000 mg/kg. The approximate lethal dose (ALD) of FPGE in SD rats was >3000 mg/kg. For the 13-week subchronic toxicity assay, no FPGE dose induced any significant change in mortality, clinical signs, body or organ weight, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination in either SD rat sex. The rat no observed adverse effects level (NOAEL) for FPGE was set to 3000 mg/kg.

CONCLUSIONS

The present study empirically demonstrated that FPGE has a safe preclinical profile and indicated that it could be safely integrated into health products for atopic dermatitis treatment.

Immunomodulatory effect of intracellular polysaccharide from mycelia of Agaricus bitorquis (QuéL.) Sacc. Chaidam by TLR4-mediated MyD88 dependent signaling pathway

Agaricus bitorquis (QuéL.) Sacc. Chaidam is a valuable edible fungus in Qinghai-Tibet plateau and ABSP is a novel intracellular polysaccharide from its mycelia. GC and NMR analysis determined ABSP is galactoglucomannan-like polysaccharide that may have immunomodulatory effect. This study used RAW264.7 as model cell to determine immunomodulatory effect of ABSP. After ABSP treatment, viability and phagocytic ability promoted, and NO, ROS, TNF-α levels also raised which proved ABSP had immune regulation to RAW264.7. WB and qRT-PCR determined the key proteins and genes expression of TLR4, MyD88, TRAF-6 and NF-κB significantly increased while protein and gene expression of TRAM had no significant increase. Also, TNF-α level extremely decreased by adding inhibitors of TLR4 and MyD88 which confirmed ABSP could immunologically regulate RAW264.7 byTLR4-MyD88 dependent pathway. This study would provide theoretical basis for further study on ABSP and be helpful for development of beneficial functionally foods and exploitation of this resource.

Characterization of an antioxidant pectic polysaccharide from Platycodon grandiflorus

Platycodonis Radix is widely used as homology of medicine and food in China; polysaccharides are thought to be one of its functional constituents. In this study, a pectic polysaccharide, PGP-I-I, was obtained from the root of the traditional medicine plant Platycodon grandiflorus through ion exchange chromatography and gel filtration. This was characterized being mainly composed of 1,5-α-L-arabinan and both arabinogalactan type I (AG-I) and II chains linked to rhamnogalacturonan I (RG-I) backbone linked to longer galacturonan chains. In vitro bioactivity study showed that PGP-I-I could restore the intestinal cellular antioxidant defense under the condition of hydrogen peroxide (H₂O₂) treatment through promoting the expressions of cellular antioxidant genes and protect against oxidative damages.

Extraction, structural elucidation and immunostimulating properties of water-soluble polysaccharides from wheat bran

A water-soluble polysaccharide was extracted from wheat bran (WBP) and investigate their structural characteristics and immunostimulatory activities. The chemical composition of WBP and purified fraction (WBP-F) mainly consists of neutral sugars (91.2 ± 1.2 and 98.7 ± 1.2%), proteins (8.6 ± 0.3 and 0.2 ± 0.1%) and uronic acids (0.7 ± 0.1 and 0.6 ± 0.1%). The molecular weight (M_w ) of WBP and WBP-F was calculated as 911.7 and 510.2 × 10³  g/mol, respectively. The WBP-F stimulates the RAW264.7 cells through the production of nitric oxide and various cytokines. The treatment of WBP-F facilitated the phosphorylation of P38, JNK, ERK, and NF-ƘB in RAW264.7 cells suggesting that they might stimulate RAW264.7 cells through the activation of NF-ƙB and MAPKs pathways. Furthermore, the structural details of WBP-F were studied by GC-MS and NMR spectrum, which confirms that the main backbone consists of 4-α-D-linked glucopyranosyl residues with branching points at C-6. PRACTICAL APPLICATIONS: Wheat bran is a potential source of health-promoting compounds. It has been reported that polysaccharides of wheat bran containing numerous beneficial activities. In this study, the wheat bran polysaccharide was extracted, fractionated and investigated their immunostimulatory activities. The results found in this study revealed that the purified polysaccharide from wheat bran potentially enhanced the RAW264.7 cells activation. Hence, these polysaccharides could be utilized as a potent immunity-enhancing agent in food and pharmaceutical industries.

PRP1, a heteropolysaccharide from Platycodonis Radix, induced apoptosis of HepG2 cells via regulating miR-21-mediated PI3K/AKT pathway

Two polysaccharides (PRP1 and PRP2) were isolated from Platycodonis Radix. Preliminary structural analysis indicated that PRP1 was composed of glucose, fructose, and arabinose in a molar ratio of 1:1.91:1.59 with a molecular weight of 440 kDa, whereas PRP2 was composed of arabinose, fructose, and galactose in a molar ratio of 1:1.39:1.18 with a molecular weight of 2.85 kDa. Compared with PRP2, PRP1 exerted stronger anticancer activity in vitro. Treatment with 5-30 μg/ml of PRP1 significantly inhibited the proliferation of HepG2 cells in vitro, and oral administration at the doses of 75-300 mg/kg also reduced the tumor growth in vivo. The miRNA expression patterns of human liver cancer cells HepG2 in vivo under PRP1 treatment were established, and microRNA-21 (miR-21) as the onco-miRNA was appreciably downregulated. PRP1 repressed the expression of miR-21, which directly targeted and suppressed PTEN (a negative regulator of the PI3K/Akt signaling cascade), and subsequently upregulated the expression of PTEN but downregulated the PI3K/AKT pathway, thereby promoting liver cancer cell apoptosis. These findings indicated that PRP1 inhibited the proliferation and induced the apoptosis of HepG2 mainly via inactivating the miR-21/PI3K/AKT pathway. Therefore, PRP1 could be used as a food supplement and candidate for the treatment of liver cancer.

Activation of RAW264.7 macrophage by Exopolysaccharide from Aphanothece halaphytica (EPSAH) and the underlying mechanisms

Exopolysaccharide from Aphanothece halophytica (EPSAH), a potent antitumor agent and immunological adjuvant, was investigated for the activation effect on RAW264.7 macrophages and the underlying mechanisms. EPSAH could significantly enhance macrophage phagocytosis and the secretion of nitric oxide, increase the mRNA expression levels of the pro-inflammatory cytokines (IL-1β, IL-6, IL-12, and TNF-α), anti-inflammatory cytokine IL-10, and chemokines (MCP-1 and MIP-1α). When RAW264.7 cells were treated with EPSAH, the mRNA expression of TLR4 and its downstream molecules TRAF6 and MyD88 were upregulated. When TLR4 was blocked using a TLR4-specific neutralizing antibody, nitric oxide secretion from the macrophages was significantly inhibited. EPSAH was further shown to induce phosphorylation of the mitogen-activated protein kinases (MAPKs) ERK, JNK, and p38, and promote cytoplasmic IκB phosphorylation and increase nuclear NF-κB p65 levels remarkably in RAW264.7 cells. These data demonstrate the capacity of EPSAH to induce macrophage activation possibly via TLR4/MyD88 pathway, which leads to the activation of its main signaling downstream molecules MAPKs and NF-κB.

Exopolysaccharide from Paecilomyces lilacinus modulates macrophage activities through the TLR4/NF‑κB/MAPK pathway

Multiple exopolysaccharides (EPSs) have been isolated from various organisms in extreme environments and have yielded a variety of activities. The present study evaluated the immunomodulatory capabilities of an EPS (termed PH‑EPS) derived from the fungus Paecilomyces lilacinus PH0016, which was isolated from a tropical and hyperhaline environment in southern China. The macrophage RAW 264.7 cell line was used to investigate the mechanism of PH‑EPS‑induced macrophage activation. The results indicated that RAW 264.7 macrophages were activated by PH‑EPS, in an effect slightly inferior to lipopolysaccharide (LPS), as evidenced by secretion of interleukin (IL)‑1β, tumor necrosis factor (TNF)‑α and nitric oxide (NO), and by significantly increased phagocytosis in the cells treated with PH‑EPS. Nuclear factor (NF)‑κB p65 was significantly translocated into the nucleus in the PH‑EPS‑treated cells. In addition, expression of inducible NO synthase (iNOS) and IκB‑α degradation were enhanced in PH‑EPS‑treated cells. The phosphorylation levels of p38, JNK and ERK were also significantly increased in the PH‑EPS‑treated cells. Furthermore, IL‑1β and TNF‑α production was markedly decreased in PH‑EPS‑treated cells when the mitogen‑activated protein kinase (MAPK) pathways were blocked by the inhibitor Dectin‑1 and by antibodies against Toll‑like receptor 4 (TLR4). The present results indicated that PH‑EPS from Paecilomyces lilacinus possessed the capability of activating RAW 264.7 cells via the TLR4/NF‑κB/MAPKs signaling pathway.

Effects of diosgenin and its derivatives on atherosclerosis

The effects of diosgenin are discussed with respect to endothelial dysfunction, lipid profile, macrophage foam cell formation, VSMC viability, thrombosis and inflammation during the formation of atherosclerosis.

Polysaccharide isolated from Sarcodon aspratus induces RAW264.7 activity via TLR4-mediated NF-κB and MAPK signaling pathways

Our previous report showed that the novel polysaccharide SAP isolated from the fruiting bodies of Sarcodon aspratus induced Hela cells apoptosis via mitochondrial dysfunction. In this study we found that SAP enhanced immunostimulatory activities of RAW264.7 cells, which was characterized by increased the production of nitric oxide (NO), reactive oxygen species (ROS), cytokines and phagocytic. However, SAP-induced macrophage activation was abolished when Toll-like receptor 4 (TLR4) signaling was blocked by anti-TLR4 antibodies. Moreover, according to the Western blot analysis and use of specific inhibitors against the MAPKs (mitogen-activated protein kinases) and NF-κB (nuclear factor-κB), we speculated that SAP activated RAW264.7 cells through TLR4-mediated activation of NF-κB and MAPKs pathways. Thus, Sarcodon aspratus is a potential immunomodulator that can be used as healthcare food.

Macrophage immunomodulatory activity of the polysaccharide isolated from Collybia radicata mushroom

Polysaccharides from Collybia radicata mushroom (CRP) possess many functions, such as antiviral, anti-aging and hypolipidemic activities. However, little is known about their immunomodulatory activity. To address this issue, we did a thorough research into their immune effects on murine macrophages. The results showed that the 14942Da polysaccharide not only obviously improved the proliferation and phagocytosis of macrophages, but also induced the secretion of nitric oxide (NO), inducible nitric oxide synthase (iNOS) and cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin factors (IL-1β, IL-6 and IL-10). At a concentration of 850.0μgmL^-1, the polysaccharide stimulated their proliferation and phagocytosis to 2.1 and 3.4 times, respectively, as compared to the negative group. Meanwhile, it raised the production of NO by inducing iNOS in a concentration-dependent manner. Furthermore, it enhanced the release of these cytokines to multiples from 2.3 to 3.6 times. As an inhibitor of TLR4 (Toll-like Receptor 4), TAK242 suppressed the secretion of NO, iNOS and cytokines above 51%, and ORP acted on the cells mainly via TLR4. Consequently, the polysaccharide has a potent immunomodulatory activity by stimulating macrophages and can be considered as a novel potential immunopotentiator in medical and food industries.

Herbal formula SC-E1 suppresses lipopolysaccharide-stimulated inflammatory responses through activation of Nrf2/HO-1 signaling pathway in RAW 264.7 macrophages

BACKGROUND

SC-E1 is a novel herbal formula consisting of five oriental medicinal herbs used frequently in traditional herbal medicine for the treatment of inflammatory diseases in Korea. This study examined the effects of SC-E1 on lipopolysaccharide (LPS)-stimulated macrophages and the molecular mechanism involved.

METHODS

The cytotoxic effect of the SC-E1 extract was evaluated in RAW 264.7 cells by MTT assay. The effects of SC-E1 on the free radical scavenging and generation of intracellular reactive oxygen species were measured using DPPH and DCFH-DA, respectively. The effects of SC-E1 on the production of pro-inflammatory cytokines, inflammatory mediators, and related products were determined by ELISA and western blotting. The molecular mechanism and the nuclear translocation of nuclear factor-kappa B (NF-κB) and NF-E2-related factor 2 (Nrf2) were examined by western blot analysis and immunocytochemistry.

RESULTS

SC-E1 exhibited strong anti-oxidant activity and inhibited LPS-induced NO secretion as well as iNOS expression and the production of pro-inflammatory cytokines, without affecting the cell viability. SC-E1 also suppressed the LPS-induced NF-κB activation and the mitogen-activated protein kinase (MAPK) pathway. Moreover, SC-E1 induced heme oxygenase-1 (HO-1) expression via the nuclear translocation of Nrf2. The inhibitory effects of SC-E1 on the production of pro-inflammatory cytokines were abrogated by treatment with SnPP, an HO-1 inhibitor.

CONCLUSION

These results suggest that SC-E1 exerts its anti-oxidant and anti-inflammatory effects through the inhibition of NF-κB and MAPK as well as Nrf2-mediated HO-1 induction in macrophages. These findings provide evidences for SC-E1 to be considered as a new prescription for treating inflammatory diseases.

Polysaccharide from wheat bran induces cytokine expression via the toll-like receptor 4-mediated p38 MAPK signaling pathway and prevents cyclophosphamide-induced immunosuppression in mice

Wheat bran-derived polysaccharides have attracted particular attention due to their immunomodulatory effects. However, the molecular mechanisms underlying their functions are poorly understood. The current study was designed to examine the effect of wheat bran polysaccharide (WBP) on RAW 264.7 cells and the underlying signaling pathways, which have not been explored. In addition, we also investigated the immuno-enhancement effects of WBP on cyclophosphamide (CTX)-induced immunosuppression in mice. WBP significantly increased the concentrations of intracellular nitric oxide (NO) and cytokines such as prostaglandin E₂ (PGE₂) and tumor necrosis factor-α (TNF-α) in RAW 264.7 cells. The result of RT-PCR analysis indicated that WBP also enhanced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α expression. Further analyses demonstrated that WBP rapidly activated phosphorylated p38 mitogen-activated protein kinase (MAPK) and the transcriptional activities of activator protein-1 (AP-1) and nuclear factor (NF)-κB via toll-like receptor 4 (TLR4). Furthermore, in vivo experiments revealed that WBP increased the spleen and thymus indices significantly, and markedly promoted the production of the serum cytokines IL-2 and IFN-γ in CTX-induced immunosuppressed mice. Taken together, these results suggest that WBP can improve immunity by enhancing immune function, and could be explored as a potential immunomodulatory agent in functional food.

Antitumor activity of orally administered maitake α-glucan by stimulating antitumor immune response in murine tumor

Maitake α-glucan, YM-2A, isolated from Grifola frondosa, has been characterized as a highly α-1,6-branched α-1,4 glucan. YM-2A has been shown to possess an anti-virus effect in mice; however, it does not directly inhibit growth of the virus in vitro, indicating that the anti-virus effect of YM-2A might be associated with modulation of the host immune system. In this study, we found that oral administration of YM-2A could inhibit tumor growth and improve survival rate in two distinct mouse models of colon-26 carcinoma and B16 melanoma. Orally administered YM-2A enhanced antitumor immune response by increasing INF-γ-expressing CD4⁺ and CD8⁺ cells in the spleen and INF-γ-expressing CD8⁺ cells in tumor-draining lymph nodes. In vitro study showed that YM-2A directly activated splenic CD11b⁺ myeloid cells, peritoneal macrophages and bone marrow-derived dendritic cells, but did not affect splenic CD11b^- lymphocytes or colon-26 tumor cells. YM-2A is more slowly digested by pancreatic α-amylase than are amylopectin and rabbit liver glycogen, and orally administered YM-2A enhanced the expression of MHC class II and CD86 on dendritic cells and the expression of MHC class II on macrophages in Peyer’s patches. Furthermore, in vitro stimulation of YM-2A increased the expression of pro-inflammatory cytokines in Peyer’s patch CD11c⁺ cells. These results suggest that orally administered YM-2A can activate dendritic cells and macrophages in Peyer’s patches, inducing systemic antitumor T-cell response. Thus, YM-2A might be a candidate for an oral therapeutic agent in cancer immunotherapy.

Physicochemical Characterization of a Polysaccharide Fraction from Platycladus orientalis (L.) Franco and Its Macrophage Immunomodulatory and Anti-Hepatitis B Virus Activities

A polysaccharide fraction, here called POP1, was purified from the leaves of Platycladus orientalis (L.) Franco by water extraction and alcohol precipitation. Physicochemical characterization indicated that POP1 had a relative molecular weight of 8.10 × 10(3) Da and consisted of rhamnose (5.74%), arabinose (12.58%), mannose (10.97%), glucose (64.96%), and galactose (6.55%). The main linkage types of POP1 consisted of (1→5)-linked α-l-Ara, (1→3)-linked α-l-Man, (1→6)-linked β-l-Rha, (1→4)-linked α-d-Glc, (1→6)-linked α-d-Glc, (1→6)-linked β-d-Gal, (1→3,6)-linked β-d-Gal, and termination with α-l-Man and α-d-Glc residues based on periodate oxidation, Smith degradation, methylation, and NMR analysis. POP1 exhibited excellent immunostimulating activity by enhancing macrophage NO, TNF-α, IL-6, and IL-12 secretion and activating related mRNA expression. Besides, POP1 showed significant anti-HBV activity through inhibiting the expression of HBsAg (IC50 = 1.33 ± 0.12 mg/mL) and HBeAg (IC50 = 1.67 ± 0.13 mg/mL) and interfering with the HBV DNA replication (IC50 = 0.80 ± 0.03 mg/mL). The present study suggested that POP1 could be used as immunoregulatory agent in functional foods for the prevention of HBV infection.

Toll-like receptor 4-related immunostimulatory polysaccharides: Primary structure, activity relationships, and possible interaction models

Toll-like receptor (TLR) 4 is an important polysaccharide receptor; however, the relationships between the structures and biological activities of TLR4 and polysaccharides remain unknown. Many recent findings have revealed the primary structure of TLR4/MD-2-related polysaccharides, and several three-dimensional structure models of polysaccharide-binding proteins have been reported; and these models provide insights into the mechanisms through which polysaccharides interact with TLR4. In this review, we first discuss the origins of polysaccharides related to TLR4, including polysaccharides from higher plants, fungi, bacteria, algae, and animals. We then briefly describe the glucosidic bond types of TLR4-related heteroglycans and homoglycans and describe the typical molecular weights of TLR4-related polysaccharides. The primary structures and activity relationships of polysaccharides with TLR4/MD-2 are also discussed. Finally, based on the existing interaction models of LPS with TLR4/MD-2 and linear polysaccharides with proteins, we provide insights into the possible interaction models of polysaccharide ligands with TLR4/MD-2. To our knowledge, this review is the first to summarize the primary structures and activity relationships of TLR4-related polysaccharides and the possible mechanisms of interaction for TLR4 and TLR4-related polysaccharides.

Exopolysaccharide from Trichoderma pseudokoningii induces macrophage activation

In this study, we evaluated the immunomodulatory activity of an exopolysaccharide (EPS) derived from Trichoderma pseudokoningii and investigated the molecular mechanism of EPS-mediated activation of macrophages. Results revealed that EPS could significantly induce the production of nitric oxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)-1β and enhance phagocytic activity in RAW 264.7 cells. Immunofluorescence staining indicated that EPS promoted the nuclear translocation of nuclear factor (NF)-κB p65 subunit. Western blot analysis showed that EPS increased the expression of inducible nitric oxide synthase (iNOS) protein, the degradation of IκB-α and the phosphorylation of mitogen-activated protein kinases (MAPKs). Furthermore, pretreatment of RAW 264.7 cells with specific inhibitors of NF-κB and MAPKs significantly attenuated EPS-induced TNF-α and IL-1β production. EPS also induced the inhibition of cytokine secretion by special antibodies against Toll-like receptor-4 (TLR4) and Dectin-1. These data suggest that EPS from Trichoderma pseudokoningii activates RAW 264.7 cells through NF-κB and MAPKs signaling pathways via TLR4 and Dectin-1.

Characterization of polysaccharide from longan pulp as the macrophage stimulator

A 44.7-kDa polysaccharide LPIIa from longan pulp was mainly composed of →6)-Glc-(1→, →5)-Ara-(1→, →4)-Man-(1→ and →6)-Gal-(1→. It stimulated macrophage activation partlyviaTLR4 and TLR2, followed by p38 MAPK- and NF-κB-dependent signaling pathways.

In vitro proliferation and production of cytokine and IgG by human PBMCs stimulated with polysaccharide extract from plants endemic to Gabon

Polysaccharides were extracted from seven plants endemic to Gabon to study their potential immunological activities. Peripheral blood mononuclear cell (PBMC) (5 × 10⁵ cells/mL) proliferation, cytokine and immunoglobulin G (IgG) assays were performed after stimulation with different concentrations of polysaccharide fractions compared with lipopolysaccharides (LPS) and concanavalin A (ConA) from healthy volunteers. The culture supernatants were used for cytokine and IgG detection by enzyme-linked immunosorbent assay (ELISA). The results show that pectin and hemicellulose extracts from Uvaria klainei, Petersianthus macrocarpus, Trichoscypha addonii, Aphanocalyx microphyllus, Librevillea klaineana, Neochevalierodendron stephanii and Scorodophloeus zenkeri induced production levels that were variable from one individual to another for IL-12 (3–40 pg/mL), IL-10 (6–443 pg/mL), IL-6 (7–370 pg/mL), GM-CSF (3–170 pg/mL) and IFN-γ (5–80 pg/mL). Only hemicelluloses from Aphanocalyx microphyllus produce a small amount of IgG (OD = 0.034), while the proliferation of cells stimulated with these polysaccharides increased up to 318% above the proliferation of unstimulated cells. However, this proliferation of PBMCs was abolished when the pectin of some of these plants was treated with endopolygalacturonase (p < 0.05), but the trend of cytokine synthesis remained the same, both before and after enzymatic treatment or saponification. This study suggests that these polysaccharides stimulate cells in a structure-dependent manner. The rhamnogalacturonan-I (RGI) fragment alone was not able to induce the proliferation of PBMC.

Activation of RAW264.7 mouse macrophage cells in vitro through treatment with recombinant ricin toxin-binding subunit B: involvement of protein tyrosine, NF-κB and JAK-STAT kinase signaling pathways

Ricin toxin-binding subunit B (RTB) is a galactose-binding lectin protein. In the present study, we investigated the effects of RTB on inducible nitric oxide (NO) synthase (iNOS), interleukin (IL)-6 and tumor necrosis factor (TNF)-α, as well as the signal transduction mechanisms involved in recombinant RTB-induced macrophage activation. RAW264.7 macrophages were treated with RTB. The results revealed that the mRNA and protein expression of iNOS was increased in the recombinant RTB-treated macrophages. TNF-α production was observed to peak at 20 h, whereas the production of IL-6 peaked at 24 h. In another set of cultures, the cells were co-incubated with RTB and the tyrosine kinase inhibitor, genistein, the phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, the p42/44 inhibitor, PD98059, the p38 inhibitor, SB203580, the JNK inhibitor, SP600125, the protein kinase C (PKC) inhibitor, staurosporine, the JAK2 inhibitor, tyrphostin (AG490), or the NOS inhibitor, L-NMMA. The recombinant RTB-induced production of NO, TNF-α and IL-6 was inhibited in the macrophages treated with the pharmacological inhibitors genistein, LY294002, staurosporine, AG490, SB203580 and BAY 11-7082, indicating the possible involvement of protein tyrosine kinases, PI3K, PKC, JAK2, p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in the above processes. A phosphoprotein analysis identified tyrosine phosphorylation targets that were uniquely induced by recombinant RTB and inhibited following treatment with genistein; some of these proteins are associated with the downstream cascades of activated JAK-STAT and NF-κB receptors. Our data may help to identify the most important target molecules for the development of novel drug therapies.

Immunomodulatory activity of polysaccharides isolated from Clerodendrum splendens: beneficial effects in experimental autoimmune encephalomyelitis

BACKGROUND

Extracts of leaves from Clerodendrum have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts.

METHODS

Polysaccharides from the leaves of Clerodendrum splendens were extracted and fractionated by ion exchange and size-exclusion chromatography. Molecular weight determination, sugar analysis, degree of methyl esterification, and other chemical characterization of the fractions were performed. Immunomodulatory activity of the fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO), cytokine production, and mitogen-activated protein kinase (MAPK) phosphorylation. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice, and severity of EAE was monitored in mice treated with intraperitoneal (i.p.) injections of the most active polysaccharide fraction. Lymph nodes (LN) and spleen were harvested, and levels of cytokines in supernatants from LN cells and splenocytes challenged with myelin oligodendrocyte glycoprotein peptide were determined.

RESULTS

Fractions containing type II arabinogalactan had potent immunomodulatory activity. Specifically, the high-molecular weight sub-fraction CSP-AU1 (average of 38.5 kDa) induced NO and cytokine [interleukin (IL)-1α, -1β, -6, -10, tumor necrosis factor (TNF; designated previously as TNF-α), and granulocyte macrophage-colony stimulating factor (GM-CSF)] production by human peripheral blood mononuclear cells (PBMCs) and monocyte/macrophages. CSP-AU1-induced secretion of TNF was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS, indicating a role for TLR4 signaling. Treatment with CSP-AU1 also induced phosphorylation of a number of MAPKs in human PBMC and activated AP-1/NF-κB. In vivo treatment of mice with CSP-AU1 and CSP-NU1 resulted in increased serum IL-6, IL-10, TNF, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α/CCL3, and MIP-1β/CCL4. CSP-AU1 treatment of mice with EAE (50 mg/kg, i.p., daily, 13 days) resulted in significantly reduced disease severity in this experimental model of multiple sclerosis. Levels of IL-13, TNF, interferon (IFN)-γ, IL-17, and GM-CSF were also significantly decreased, whereas transforming growth factor (TGF)-β was increased in LN cells from CSP-AU1-treated EAE mice.

CONCLUSIONS

Polysaccharide CSP-AU1 is a potent natural innate immunomodulator with a broad spectrum of agonist activity in vitro and immunosupressive properties after chronic administration in vivo.

Immune-stimulatory and anti-inflammatory activities of Curcuma longa extract and its polysaccharide fraction

Background:

While curcuminoids have been reported to possess diverse biological activities, the anti-inflammatory activity of polar extracts (devoid of curcuminoids) of Curcuma longa (C. longa) has seldom been studied. In this study, we have investigated immune-stimulatory and anti-inflammatory activities of an aqueous based extract of C. longa (NR-INF-02) and its fractions in presence and absence of mitogens.

Materials and Methods:

Effects of NR-INF-02 (Turmacin™, Natural Remedies Pvt. Ltd., Bangalore, India) on proliferation, nitric oxide (NO), monocyte chemotactic protein-1 (MCP-1), interleukins (ILs) and prostaglandin (PGE₂) levels of mouse splenocytes and mouse macrophage (RAW264.7) cells were determined.

Results:

NR-INF-02 increased splenocytes number in presence and absence of lipopolysaccharide (LPS) or concanavalin A. Treatment of NR-INF-02 showed a significant increase of NO, IL-2, IL-6, IL-10, IL-12, interferon (IFN) gamma, tumor necrosis factor (TNF) alpha and MCP-1 production in unstimulated mouse splenocytes and mouse macrophages. Interestingly, NR-INF-02 showed potent inhibitory effect towards release of PGE₂ and IL-12 levels in LPS stimulated mouse splenocytes. Further, NR-INF-02 was fractionated into polysaccharide fraction (F1) and mother liquor (F2) to study their immune-modulatory effects. F1 was found to be more potent than F2 toward inhibiting PGE₂ and IL-12 in LPS stimulated splenocytes.

Conclusion:

Present findings revealed the novel anti-inflammatory property of NR-INF-02 and its polysaccharide fraction by inhibiting the secretion of IL-12 and PGE₂in vitro.

Anti-inflammatory effects of saponins derived from the roots of Platycodon grandiflorus in lipopolysaccharide‑stimulated BV2 microglial cells

Radix platycodi is the root of Platycodon grandiflorus A. DC, which has been widely used as a food material and for the treatment of a number of chronic inflammatory diseases in traditional oriental medicine. In this study, the anti‑inflammatory effects of the saponins isolated from radix platycodi (PGS) on the production of inflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated BV2 murine microglial cells were examined. We also investigated the effects of PGS on LPS‑induced nuclear factor‑κB (NF-κB) activation and phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) signaling pathways. Following stimulation with LPS, elevated nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokine production was detected in the BV2 microglial cells. However, PGS significantly inhibited the excessive production of NO, PGE2 and pro‑inflammatory cytokines, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in a concentration-dependent manner without causing any cytotoxic effects. In addition, PGS suppressed NF-κB translocation and inhibited the LPS-induced phosphorylation of AKT and MAPKs. Our results indicate that the inhibitory effect of PGS on LPS-stimulated inflammatory response in BV2 microglial cells is associated with the suppression of NF-κB activation and the PI3K/AKT and MAPK signaling pathways. Therefore, these findings suggest that PGS may be useful in the treatment of neurodegenerative diseases by inhibiting inflammatory responses in activated microglial cells.

Immunomodulatory activity of polysaccharides isolated from Alchornea cordifolia

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of leaves from different species of the genus Alchornea have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts.

OBJECTIVE

The aim of this study was to evaluate the immunomodulatory activity of polysaccharides isolated from the leaves of Alchornea cordifolia.

MATERIALS AND METHODS

Water-soluble polysaccharides from leaves of Alchornea cordifolia were extracted and fractionated by DEAE-cellulose, Diaion HP-20, and size-exclusion chromatography. Molecular weight, sugar analysis, and other physical and chemical characterization of the fractions were performed. Immunomodulatory activity of the polysaccharide fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO) and cytokine production. Activation of mitogen activated protein kinases (MAPK) was also assessed using a phospho-MAPK array. Activation of nuclear factor κB (NF-κB) was measured using an alkaline phosphatase reporter gene assay in THP1-Blue monocytic cells.

RESULTS

Six polysaccharide fractions from Alchornea cordifolia were isolated. Fractions containing type II arabinogalactan had potent immunomodulatory activity. Particularly, the parent fraction AP-AU and its high-molecular weight sub-fraction AP-AU1 (average M(r) was estimated to be 39.5kDa) induced production of NO and cytokines [interleukin (IL)-1β, -6, -10, tumor necrosis factor (TNF)-α, and granulocyte-macrophage-colony stimulating factor (GM-CSF)] in human peripheral blood mononuclear cells and human and murine monocyte/macrophages cell lines in vitro. Furthermore, treatment with AP-AU1 induced phosphorylation of Akt2, p38δ/p38γ, p70S6K1, RSK2, and mTOR, as well as stimulation of NF-κB transcriptional activity.

CONCLUSION

Our results provide a molecular basis to explain a portion of the beneficial therapeutic properties of water extracts from Alchornea cordifolia leaves in traditional folk medicine of Africa.

Immunomodulatory and hemagglutinating activities of acidic polysaccharides isolated from Combretum racemosum

Extracts of leaves of different species of the genus Combretum have been used historically to treat a variety of medicinal problems. However, little is known about the active components conferring therapeutic properties to these extracts. In the present studies, we evaluated biochemical properties and immunomodulatory activity of polysaccharides isolated from the leaves of Combretum racemosum. Water-soluble polysaccharides from leaves of C. racemosum were extracted and fractionated by DEAE-cellulose and Diaion HP-20 to obtain a Diaion-bound fraction, designated Combretum polysaccharide-acidic bound or CP-AB, which was eluted with methanol, and an unbound fraction, designated as CP-AU. Molecular weight determination, sugar analysis, and other physical and chemical characterization of the fractions were performed. Fraction CP-AU (mol. weight 5.0 kDa) contained type II arabinogalactan and had potent immunomodulatory activity, inducing the production of interleukin (IL)-1β, -6, -10, and tumor necrosis factor-α (TNF-α) by human peripheral blood mononuclear cells (PBMC) and MonoMac-6 monocytic cells. Likewise, intraperitoneal administration of CP-AU increased in vivo serum levels of IL-6 and monocyte chemoattractant protein-1 (MCP-1) in mice. CP-AU-induced secretion of TNF-α in PBMC was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS. Treatment with CP-AU induced phosphorylation of Akt2, Akt3, GSK-3β, HSP27, mTOR, and all p38 MAPK isoforms (α, β, δ, and γ), as well as stimulation of AP-1/NF-κB transcriptional activity. In addition, CP-AU effectively agglutinated erythrocytes from several species, including human, mouse, and rabbit. In contrast, fraction CP-AB was inactive in all biological tests, including cytokine production and hemagglutination. These data suggest that at least part of the beneficial therapeutic effects reported for the water extracts of leaves from C. racemosum are due to modulation of leukocyte functions.

Improvement of atopic dermatitis-like skin lesions by Platycodon grandiflorum fermented by Lactobacillus plantarum in NC/Nga mice

Atopic dermatitis (AD) is characterized as a multi-factorial inflammatory skin disease that has been increasing worldwide. Previously, we demonstrated that FPG, which is Platycodon grandiflorum (PG) fermented by Lactobacillus plantarum (LP), increases the level of interferon (IFN)-gamma in mouse splenocytes in vitro. In this study, we investigated the effects of FPG in an animal model of AD, with a particular emphasis on its effects on T helper (Th)1 and Th2 immune responses. To assess the potential use of FPG for the inhibition of AD, we established a model of AD-like skin lesions in NC/Nga mice. Immunoglobulin isotypes (Igs) and Th1/Th2 cytokines in the sera and spleens of AD-like mice were examined. In addition, histological examination was also performed. AD symptoms in skin lesions improved following oral administration of FPG. IgE secretion was significantly down-regulated, and this was accompanied by decreased levels of interleukin (IL)-4 and IgG1 and increased serum levels of IL-12p40 and IgG2a in FPG-treated animals. In splenocytes, the production of the Th1 cytokines IL-12p40 and IFN-gamma was up-regulated, while the levels of the Th2 cytokines IL-4 and 5 were down-regulated by FPG treatment. These results suggest that FPG inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the Th2 cell response and increasing the Th1 cell responses. Our results indicate that FPG is safe and effective for the prevention of AD-like skin lesions.

Activation of macrophages by polysaccharide isolated from Paecilomyces cicadae through toll-like receptor 4

Paecilomyces cicadae have been reported to have immunomodulatory properties. In this study, we investigated the effect of polysaccharide (PCP) isolated from P. cicadae on the macrophages. PCP increased the production of nitric oxide (NO) and the gene expression of IL-1β, IL-6, and TNF-α in RAW 264.7 cells. To investigate the membrane receptor, we examined the effect of PCP on primary macrophages isolated from wild type C3H/HeN and C3H/HeJ mice having mutant-TLR4. PCP induced NO production and cytokine gene expression in macrophages from C3H/HeN, but not from tlr4-mutated C3H/HeJ mice, which suggests that TLR4 is the membrane receptor for PCP. PCP induced the phosphorylation of ERK, JNK, and p38, and the nuclear translocation of NF-κB p50/p65, which are the main signaling molecules downstream from TLR4. Among them, p38 and NF-κB signaling played a crucial role in PCP-induced NO production by macrophages. These results indicate that PCP activates macrophages through the TLR4 signaling pathway.

Inhibitory effect of Platycodon grandiflorum on T(H)1 and T(H)2 immune responses in a murine model of 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions

BACKGROUND

Platycodon grandiflorum is a traditional Asian medicine that is used to treat pulmonary and respiratory allergic disorders.

OBJECTIVE

to investigate the effects of P grandiflorum in vivo in an animal model of atopic dermatitis (AD), with particular emphasis on its effects on T(H)1 and T(H)2 immune responses.

METHODS

we established a model of AD-like skin lesions in NC/Nga mice. After oral administration of P grandiflorum, we measured cytokine and immunoglobulin profiles along with histologic examination of skin.

RESULTS

P grandiflorum was nontoxic in a 2,4-dinitrofluorobenzene-induced model of AD-like skin lesions in NC/Nga mice. AD symptoms in skin lesions improved after oral administration of P grandiflorum. IgE secretion was significantly downregulated in P grandiflorum-treated animals, accompanied by decreased levels of interleukin (IL) 4 and IgG1 and increased serum levels of IL-12p40 and IgG2a. In isolated splenocytes, the production of the T(H)1 cytokines IL-12p40 and interferon-γ was upregulated by P grandiflorum, whereas the levels of the T(H)2 cytokines IL-4 and IL-5 were downregulated in a mouse model of AD-like skin lesions.

CONCLUSIONS

these results suggest that P grandiflorum inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the T(H)2 cell response and increasing the T(H)1 cell responses. Our results indicate that P grandiflorum is safe and effective as a natural herbal medicine for the treatment of AD-like skin lesions.

Antiproliferative effects of saponins from the roots of Platycodon grandiflorum on cultured human tumor cells

Three new triterpenoid saponins, platyconic acid B lactone (1), deapio-platyconic acid B lactone (2), and deapio-platycodin D(2) (3), together with 17 known triterpenoid saponins, were isolated from a root extract of Platycodon grandiflorum. The structures of 1-3 were determined on the basis of spectroscopic data interpretation and chemical transformation. Saponins with a platycodigenin or polygalacic acid unit as a sapogenin demonstrated significant inhibitory effects on the proliferation of a small panel of cultured human tumor cells.

Glabridin inhibits lipopolysaccharide-induced activation of a microglial cell line, BV-2, by blocking NF-kappaB and AP-1

Glabridin, a flavonoid present in licorice root, is known to have antiinflammatory and cardiovascular protective activities. The present study reports an inhibitory effect of glabridin on microglial activation. Glabridin dose-dependently attenuated lipopolysaccharide (LPS)-induced production of inflammatory mediators, including nitric oxide, tumor necrosis factor-alpha and interleukin-1beta, in BV-2 cells, a murine microglia cell line. Moreover, mRNA expression of these inflammatory mediators was also suppressed by glabridin in LPS-stimulated BV-2 cells. Further study demonstrated that glabridin inhibited LPS-induced DNA binding activity of NF-kappaB and AP-1 in BV-2 cells. Collectively, the results presented in this report demonstrate that glabridin inhibits the production of inflammatory mediators in BV-2 cells and this is mediated, at least in part, by blocking NF-kappaB and AP-1 activation. The results suggest that glabridin might be a potential therapeutic agent for the treatment of neuroinflammatory and neurodegenerative diseases.