Identification of plant compounds that disrupt the insect juvenile hormone receptor complex.

Insects impact human health through vector-borne diseases and cause major economic losses by damaging crops and stored agricultural products. Insect-specific growth regulators represent attractive control agents because of their safety to the environment and humans. We identified plant compounds that serve as juvenile hormone antagonists (PJHANs). Using the yeast two-hybrid system transformed with the mosquito JH receptor as a reporter system, we demonstrate that PJHANs affect the JH receptor, methoprene-tolerant (Met), by disrupting its complex with CYCLE or FISC, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants: Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD50 values. Topical application of two diterpenes caused reduction in the expression of Met target genes and retardation of follicle development in mosquito ovaries. Hence, the newly discovered PJHANs may lead to development of a new class of safe and effective pesticides.

3-Methoxy-catalposide inhibits inflammatory effects in lipopolysaccharide-stimulated RAW264.7 macrophages.

Pseudolysimachion rotundum var. subintegrum is utilized as a traditional herbal remedy to treat cough, bronchitis, and asthma in Korea, Russia, China, and Europe. Here, we show that 3-methoxy-catalposide, a novel iridoide glycoside isolated from P. rotundum var. subintegrum has the anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated macrophages. The chemical structure of 3-methoxy-catalposide was determined by NMR, optical rotation and HRESIMS. In in vitro experiment, RAW264.7 cells were treated with 3-methoxy-catalposide for 2h before exposure to LPS for different times. Inflammatory gene and protein expressions were assayed using RT-PCR and ELISA. Activities of signal proteins were examined using western analysis. Our results demonstrated that 3-methoxy-catalposide significantly inhibits the expression of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in RAW264.7 cells stimulated by LPS, thereby suppressing the release of prostaglandin E2 (PGE2) and nitric oxide (NO). Moreover, 3-methoxy-catalposide markedly reduced the LPS-induced expression of pro-inflammatory genes, such as interleukin (IL)-6, IL-1ß, and TNF-α. Further, 3-methoxy-catalposide inhibited both LPS-induced activation of three MAP kinases (ERK 1/2, JNK, and p38) and the nuclear translocation of NF-κB and AP-1. These results support that 3-methoxy-catalposide may be a promising candidate for inflammation treatment.

Conifer Diterpene Resin Acids Disrupt Juvenile Hormone-Mediated Endocrine Regulation in the Indian Meal Moth Plodia interpunctella.

Diterpene resin acids (DRAs) are important components of oleoresin and greatly contribute to the defense strategies of conifers against herbivorous insects. In the present study, we determined that DRAs function as insect juvenile hormone (JH) antagonists that interfere with the juvenile hormone-mediated binding of the JH receptor Methoprene-tolerant (Met) and steroid receptor coactivator (SRC). Using a yeast two-hybrid system transformed with Met and SRC from the Indian meal moth Plodia interpunctella, we tested the interfering activity of 3704 plant extracts against JH III-mediated Met-SRC binding. Plant extracts from conifers, especially members of the Pinaceae, exhibited strong interfering activity, and four active interfering DRAs (7α-dehydroabietic acid, 7-oxodehydroabietic acid, dehydroabietic acid, and sandaracopimaric acid) were isolated from roots of the Japanese pine Pinus densiflora. The four isolated DRAs, along with abietic acid, disrupted the juvenile hormone-mediated binding of P. interpunctella Met and SRC, although only 7-oxodehydroabietic acid disrupted larval development. These results demonstrate that DRAs may play a defensive role against herbivorous insects via insect endocrine-disrupting activity.

Novel TRAIL sensitizer Taraxacum officinale F.H. Wigg enhances TRAIL-induced apoptosis in Huh7 cells.

TRAIL (TNF-related apoptosis inducing ligand) is a promising anti-cancer drug target that selectively induces apoptosis in cancer cells. However, many cancer cells are resistant to TRAIL-induced apoptosis. Therefore, reversing TRAIL resistance is an important step for the development of effective TRAIL-based anti-cancer therapies. We previously reported that knockdown of the TOR signaling pathway regulator-like (TIPRL) protein caused TRAIL-induced apoptosis by activation of the MKK7-c-Jun N-terminal Kinase (JNK) pathway through disruption of the MKK7-TIPRL interaction. Here, we identified Taraxacum officinale F.H. Wigg (TO) as a novel TRAIL sensitizer from a set of 500 natural products using an ELISA system and validated its activity by GST pull-down analysis. Furthermore, combination treatment of Huh7 cells with TRAIL and TO resulted in TRAIL-induced apoptosis mediated through inhibition of the MKK7-TIPRL interaction and subsequent activation of MKK7-JNK phosphorylation. Interestingly, HPLC analysis identified chicoric acid as a major component of the TO extract, and combination treatment with chicoric acid and TRAIL induced TRAIL-induced cell apoptosis via JNK activation due to inhibition of the MKK7-TIPRL interaction. Our results suggest that TO plays an important role in TRAIL-induced apoptosis, and further functional studies are warranted to confirm the importance of TO as a novel TRAIL sensitizer for cancer therapy. © 2015 Wiley Periodicals, Inc.

Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells.

Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells.

Anti-allergic flavones from Arthraxon hispidus.

Bioactivity-guided fractionation for an EtOAc-soluble fraction of methanolic extract of Arthraxon hispidus, using primary cell assay with bone marrow-derived mast cells (BMMC), led to an isolation of six new flavones and nine known compounds. The structures of the new compounds were established by one dimensional (1D)- and 2D-NMR spectroscopic data, as luteolin 8-C-ß-kerriopyranoside (1), luteolin 8-acetic acid methyl ester (2), 7-methyl-luteolin 8-C-ß-(6-deoxyxylo-3-uloside) (3), apigenin 8-C-α-fucopyranoside (4), apigenin 8-C-ß-fucopyranoside (5) and luteolin 8-C-ß-fucopyranoside (6). All the isolates were evaluated for inhibitory activities on interleukin-6 release in the primary cultures using BMMC. Of the tested compounds, compounds 2, 3 and 10 were found to inhibit interleukin-6 release. Furthermore, compound 2 displayed inhibitory activity against prostaglandin D2, leukotriene C4, and ß-hexosaminidase releases.

Tigliane diterpene esters with IFN γ-inducing activity from the leaves of Aleurites fordii.

Bioactivity-guided fractionation on the leaves of Aleurites fordii led to the isolation of a new tigliane diterpene ester, 12-O-hexadecanoyl-7-oxo-5-ene-16-hydroxyphorbol-13-acetate (1) along with four known compounds, 12-O-hexadecanoyl-7-oxo-5-ene-phorbol-13-acetate (2), 12-O-hexadecanoyl-phorbol-13-acetate (3), 12-O-hexadecanoyl-16-hydroxyphorbol-13-acetate (4), and 12-O-hexadecanoyl-4-deoxy-4α-16-hydroxyphorbol-13-acetate (5). The structures of these compounds were determined by interpretation of NMR (1D and 2D) spectroscopic data and MS data. All the isolates were evaluated for their effects on the induction of IFN-γ in NK92 cells. Compounds 3 and 4 exhibited the most potent responses in IFN-γ induction, comparable to the positive control, phorbol 12-myristate 13-acetate (PMA).

Cytotoxic terpenes from the stems of Dipterocarpus obtusifolius collected in Cambodia.

From the stems of Dipterocarpus obtusifolius, five new triterpenes, 3-oxo-20-hydroxy-30α-methyl,17(29)α-epoxy-28-norlupane (1), 3-oxo-20-hydroxy-30ß-methyl-17(29)α-epoxy-28-norlupane (2), 3,20-dioxo-28,29-norlupan-17α-ol (3), 27-demethyl-20(S)-dammar-23-ene-20-ol-3,25-dione (4), and 3-epi-cecropic acid (5) together with 13 known compounds including diterpene, sesquiterpenes and triterpenes were isolated and characterized. All isolates were tested for their cytotoxicities against a small panel of human cancer cell lines. Of the tested compounds, compounds 4-11 were found to be cytotoxic against one or more human cancer cell lines.

Cytotoxicities of enniatins H, I, and MK1688 from Fusarium oxysporum KFCC 11363P.

Enniatins (ENs) H, I, and MK1688 and beauvericin (BEA) were purified from concentrated chloroform extracts of Fusarium oxysporum KFCC 11363P submerged cultures using HPLC, and their in vitro cytotoxicities were evaluated against four human carcinoma cell lines (lung, A549; ovarian, SK-OV-3; skin melanoma, SK-MEL-2; and colon, HCT15) using the sulforhodamine B (SRB) method. ENs I and MK1688 inhibited the growth of cancer cell lines most strongly and had similar cytotoxic effects on the tested human cancer cell cultures. The cytotoxicity of ENs I and MK1688 was three- to fourfold higher than that of BEA and EN H. When cultivated in Fusarium-defined medium (FDM), the concentrations of ENs and BEA produced in F. oxysporum KFCC 11363P decreased in the following order: EN MK1688 (0.81 g/L) >EN I (0.55 g/L) >BEA (0.17 g/L) > EN H (0.16 g/L). This study has shown that ENs H, I, and MK1688 exhibit cytotoxicity against certain adenocarcinoma cell lines. The results indicate the need for more investigations into the significance of the biological properties of these new ENs.

Diversity in Beauvericin and Enniatins H, I, and MK1688 by Fusarium oxysporum isolated from potato.

Beauvericins and enniatins are cyclohexadepsipeptide mycotoxins that exhibit phytotoxicity and insecticidal activities. In the present study, the production of beauvericin and newly found enniatins (H, I, and MK1688) was characterized in 28 Fusarium strains isolated from potato samples in Korea. The predominant Fusarium species in potato was F. oxysporum (53.6%). Fifteen strains of F. oxysporum and two strains of other Fusarium species produced beauvericin (at concentrations from 3.1 to 743.2 microg/g) in culture on rice. Enniatins H and I were produced by 3 and 11 strains at concentrations from 33.1 to 781.3 microg/g and from 6.5 to 730.3 microg/g, respectively. Five isolates produced enniatin MK1688 at concentrations from 4.6 to 432.6 microg/g. In particular, one isolate (No. 1501) identified as F. oxysporum and two other Fusarium strains (Nos. 804 and 910) produced all of the tested toxins. These results indicate that enniatins H, I, and MK1688 and beauvericin are produced by Fusarium isolates occurring on potato. We do not know if the toxins can accumulate in the environment since it was not demonstrated.

Statistical optimization of growth medium for the production of the entomopathogenic and phytotoxic cyclic depsipeptide beauvericin from Fusarium oxysporum KFCC 11363P.

The production of the entomopathogenic and phytotoxic cyclic depsipeptide beauvericin (BEA) was studied in submerged cultures of Fusarium oxysporum KFCC 11363P isolated in Korea. The influences of various factors on mycelia growth and BEA production were examined in both complete and chemically defined culture media. The mycelia growth and BEA production were highest in Fusarium defined medium. The optimal carbon and nitrogen sources for maximizing BEA production were glucose and NaNO3, respectively. The carbon/ nitrogen ratio for maximal production of BEA was investigated using response surface methodology (RSM). Equations derived by differentiation of the RSM model revealed that the production of BEA was maximal when using 108 mM glucose and 25 mM NaNO3.

Cytotoxic activities of Telectadium dongnaiense and its constituents by inhibition of the Wnt/ß-catenin signaling pathway.

BACKGROUND: Wnt/ß-catenin signaling pathway is a potential target for the treatment of human colon cancer. Thus, the inhibitory effects of various plant extracts on cell proliferation and Wnt signal transduction were evaluated to discover a Wnt signaling inhibitor. PURPOSE: The present study aimed to investigate the cytotoxicity involved in Wnt pathway of the MeOH extract from Telectadium dongnaiense bark (TDB) and to identify its bioactive constituents by bioassay-guided fractionation. METHODS: The sulforhodamine B-based proliferation assay and the ß-catenin/TCF-responsive reporter gene assay were employed as screening systems. The isolation and identification of compounds were elucidated on the basis of spectroscopic methods. Inhibitory effects on the expression levels of Wnt target genes were determined by real-time PCR and western blotting. RESULTS: The extract of TDB most strongly inhibited cell proliferation and TOPflash activity (IC50 = 1.5 and 2.0 µg/ml), which was correlated with its inhibitory effects on the expression of Wnt target genes. Three major compounds were isolated from bioactive fractions and were identified as 1,4-dicaffeoylquinic acid (1), quercetin 3-rutinoside (2), and periplocin (3). Only compound 3 showed anti-proliferative activity (IC50 = 0.06 µM) and exhibited Wnt signaling inhibitory effects in HCT116 colon cancer cells. CONCLUSIONS: This study contributes to understanding the cytotoxic properties of TDB extract and its constituents and provides a potent strategy for its further application.

Inhibitory Effects of Norwogonin, Oroxylin A, and Mosloflavone on Enterovirus 71.

Severe complications associated with EV71 infections are a common cause of neonatal death. Lack of effective therapeutic agents for these infections underlines the importance of research for the development of new antiviral compounds. In the present study, the anti-EV71 activity of norwogonin, oroxylin A, and mosloflavone from Scutellaria baicalensis Georgi was evaluated using a cytopathic effect (CPE) reduction method, which demonstrated that all three compounds possessed strong anti-EV71 activity and decreased the formation of visible CPEs. Norwogonin, oroxylin A, and mosloflavone also inhibited virus replication during the initial stage of virus infection, and they inhibited viral VP2 protein expression, thereby inhibiting viral capsid protein synthesis. However, ribavirin has a relatively weaker efficacy compared to the other drugs. Therefore, these findings provide important information that will aid in the utilization of norwogonin, oroxylin A, and mosloflavone for EV71 treatment.

Ethanol extract of the tuber of Alisma orientale reduces the pathologic features in a chronic obstructive pulmonary disease mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: The tuber of Alismataceae Alisma orientale Juzepzuk has been prescribed as a remedy for treating the diseases associated with body fluid dysfunction such as edema and inflammatory lung diseases. Chronic obstructive pulmonary disease (COPD) is a debilitating, inflammatory lung disease without effective treatment. Along with persistent inflammation, autophagy has been recently reported to contribute to COPD. Here, by employing a murine model, we examined whether the tuber of the plant is effective against COPD MATERIALS AND METHODS: The ethanol extract of the tuber of A. orientale Juzepzuk (EEAO) was fingerprinted by HPLC. For the establishment of COPD lung, mice received single intratracheal (i.t.) spraying of elastase and LPS per week for 2 weeks. After approximated to the dose prescribed typically to patients, EEAO was administered to the lung 2h after each LPS treatment. Morphometric analyses, semi-quantitative RT-PCR, and western blot were performed to evaluate the effects of EEAO on emphysema, inflammation, and autophagy in mouse lungs. The effect of EEAO on autophagy was also assessed by western blot at the cellular level with murine macrophages and human lung epithelial cells. RESULTS: When receiving i.t. elastase and LPS for 2 weeks, mice developed emphysema and inflammation in the lung. EEAO treatment, however, significantly reduced emphysema and inflammatory cell infiltration to the lung with concomitant decrease of the production of pro-inflammatory cytokines including TNF-α, IL-6, and TGF-ß, signature cytokines of COPD. Unlike control mice, the lungs of the COPD mice expressed LC3-II, a biomarker for autophagy formation, which was decreased by EEAO treatment. EEAO also lowered the expression of LC3-II in murine macrophage, RAW 264.7, and human lung epithelial cell, BEAS-2B, which was associated with EEAO activating mTOR. CONCLUSION: EEAO relieved COPD pathologic features in a mouse model, which was associated with suppression of lung inflammation, emphysema, and autophagy. Our results suggest an effectiveness of the tuber of A. orientale in chronic inflammatory lung diseases such as COPD.

Phenylacylphenol derivatives with anti-melanogenic activity from Stewartia pseudocamellia.

Three new phenylacylphenol derivatives, stewartianol (1), deoxystewartianol-4'-O-arabinoglucoside (2), and stewartianol-3-O-glucoside (3), along with nine known compounds, methylesculin (4), fraxoside (5), fraxetin (6), scopletin (7), (+)-dihydromyricetin (8), (+)-taxifolin-7-O-ß-D-glucose (9), (+)-taxifolin (10), (+)-dihydrokaempferol-7-O-ß-D-glucose (11), and 3-acetyl-ursolic acid (12), were isolated from the twigs of Stewartia pseudocamellia; commonly used as folk medicine in Korea. The structures of the isolated compounds were identified using spectroscopic analysis, including 1D, 2D NMR, MS and compared with published data. The compounds were tested for their anti-melanogenic activity in cultured murine B16 melanoma cells. Stewartianol (1) and stewartianol-3-O-glucoside (3) showed an inhibitory effect significantly on melanogenesis in a concentration-dependent manner.

Antiviral Activity of Oroxylin A against Coxsackievirus B3 Alleviates Virus-Induced Acute Pancreatic Damage in Mice.

The flavonoids mosloflavone, oroxylin A, and norwogonin, which were purified from Scutellaria baicalensis Georgi, significantly protected Vero cells against Coxsackievirus B3 (CVB3)-induced cell death. To investigate the in vivo antiviral activity of oroxylin A, we intraperitoneally inoculated CVB3 into 4-week-old BALB/c mice. Body weights and blood glucose levels of the mice were decreased after CVB3 infection, and these changes were attenuated by the administration of oroxylin A. Importantly, treatment of mice with oroxylin A reduced viral titers in the pancreas and decreased the serum levels of the inflammatory cytokines including interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α. Additionally, the administration of oroxylin A mitigated the histological pancreatic lesions and apoptotic cell death induced by CVB3 infection and increased the levels of phospho-eIF2α in infected pancreata. The results suggest that oroxylin A may represent a potent antiviral agent against CVB3 infection.

Euphorbia supina inhibits inflammatory mediators in mouse bone marrow-derived mast cells and macrophages.

Euphorbia supina has been traditionally used for the treatment of furuncle and bloody diarrhea relevant to the inflammatory process. It has been proven to have a variety of pharmacological efficacies including antiarthritic, detoxification, hemostatic, and diuretic activities. RAW 264.7 macrophages and bone marrow-derived mast cells (BMMCs) were used to determine the anti-inflammatory and anti-allergic effects of E. supina (ES). NO production was assayed by measuring the nitrite content of the supernatants of cultured RAW 264.7 cells. ß-hexosaminidase, a marker of mast cell degranulation, was quantitated by spectrophotometric analysis. ELISA was used for the analysis of interleukin-6 expression, and Western blotting was used to analyze 5-LOX, iNOS, and MAPK activation. The relevant gene expression upon ES treatment was measured by RT-PCR. ES inhibited inducible nitric oxide synthase (iNOS) in RAW 264.7 cells, and IL-6 and LTC4 production in PMA- and A23187-induced BMMCs along with the downregulation of 5-LOX gene expression. Furthermore, in the present study, a decrease in p-ERK, p-JNK, and p-P38 expression, as well as the suppression of degranulation, were observed by treatment with ES. Further in vivo study revealed that ES treatment also remarkably inhibited xylene-induced mouse ear edema and MPO levels in mice ears. This study demonstrates that ES has a potential regulatory effect on the expression of inflammatory mediators through the inhibition of both the phosphorylation of MAPK signaling and the activation of degranulation.

The effect of 4α,5α-epoxy-10α,14-dihydro-inuviscolide, a novel immunosuppressant isolated from Carpesium abrotanoides, on the cytokine profile in vitro and in vivo.

The plant Carpesium abrotanoides (CA) is used in Asian herbal medicines as an insecticide and to treat bruises. However, the effect of single compounds from CA blooms and the mechanism of its immunosuppressive effect remain poorly understood. The aim of this study was to investigate the mechanism of the immunosuppressive effect in the three kinds of immune cells, and the immunosuppressive effect of CA bloom extract (CAE) in acute inflammation models (LPS and ConA-induced inflammation). Interleukin-6, IL-4, IL-13, IFNγ, and IL-10-but not TNFα-were significantly reduced in a dose-dependent manner by 4α,5α-epoxy-10α,14-dihydro-inuviscolide (INV). Furthermore, INV inhibited NF-κB transcriptional activation and IL-10 promoter activity in the same manner as for Bay11. Meanwhile, treatment with dexamethasone reduced the levels of IFNγ, but not IL-10, and resulted in no change in NF-κB transcriptional activation or the IL-10 promoter. INV did not affect PMA-induced IκB kinase complex phosphorylation, IκB degradation, or MAPK and the nuclear translocation of p65, as with DEX. The in vivo, CAE has an immunosuppressive effect on the LPS-induced inflammation response model by inhibiting the plasma level of IFNγ and IL-6 levels. CAE treatment also tends to attenuate the plasma level of IFNγ, IL-4, and IL-6 in ConA-induced inflammation. These findings indicate that INV causes the reduction of the cytokine profile by blocking the NF-κB transcription factor activation and the molecular mechanism by which INV operates could provide new insights into the unique mechanisms responsible for NF-κB inhibition, in contrast to established immunosuppressants, as a therapeutic agent for immunopathological treatment.

Luteolin 8-C-ß-fucopyranoside downregulates IL-6 expression by inhibiting MAPKs and the NF-κB signaling pathway in human monocytic cells.

Numerous studies have been suggested that derivatives can improve the effects of original substances. Therefore, we made luteolin derivative luteolin 8-C-ß-fucopyranoside (LU8C-FP) for better anti-inflammatory and anti-cancer effects. In a previous study, we demonstrated that LU8C-FP inhibits invasion of human breast cancer cells via suppression of matrix metalloproteinase 9 and IL-8, which play major roles in tumor progression and cancer cell invasion. Various stimuli trigger inflammatory responses by inducing pro-inflammatory cytokines and chemokines in THP-1 cells. IL-6 induces inflammation via inducing various cytokines and appears to be a potential mediator of inflammatory diseases. Here, we investigated the precise mechanism by which LU8C-FP inhibited phorbol 12-myristate 13-acetate-induced IL-6 mRNA and protein expression. We showed LU8C-FP downregulated IL-6 expression by inhibiting mitogen-activated protein kinases and the nuclear factor-kappaB signaling pathway in human monocytic cells. Furthermore, LU8C-FP exerts less cytotoxicity than luteolin and also it has specific inhibitory effect on IL-6 expression. However, luteolin has a variety of inhibitory effects on pro-inflammatory cytokines and chemokines. Our in vitro studies may provide valuable information leading to the use of LU8C-FP to treat inflammatory diseases caused by IL-6.

Piscroside C, a novel iridoid glycoside isolated from Pseudolysimachion rotundum var. subinegrum suppresses airway inflammation induced by cigarette smoke.

ETHNOPHARMACOLOGICAL RELEVANCE: Pseudolysimachion rotundum var. subintegrum (Speedwell, Plantaginaceae) is used as a traditional herbal medicine for treating bronchitis, cough and asthma in Korea, China, Russia, and Europe. AIM OF THE STUDY: In this study, we investigated the protective effects of the novel iridoid glycoside, piscroside C (compound 1) isolated from the methanolic extract of P. rotundum var. subintegrum against inflammatory responses using a cigarette smoke induced chronic obstructive pulmonary disease (COPD) and TNF-α-stimulated human airway epithelial NCI-H292 cells. MATERIALS AND METHODS: The novel iridoid glycoside piscroside C was isolated from the methanolic extract of P. rotundum var. subintegrum. The chemical structure was established by NMR, HRESIMS, and optical rotation. In in vivo experiment, the mice received 1h of cigarette smoke for 3 days. Piscroside C was administered to mice by oral gavage 1h before cigarette smoke exposure for 3 days. In in vitro experiment, we evaluated the effect of piscroside C on proinflammatory mediators in H292 cells stimulated with TNF-α. RESULTS: Piscroside C significantly reduced the neutrophil influx, reactive oxygen species production, IL-6, TNF-α, and elastase activity in bronchoalveolar lavage fluid in COPD animals. In addition, piscroside C attenuated NF-κB and IκB phosphorylation, leading to reduced recruitment of inflammatory cells into the lung tissue. Consistent with the results of in vivo experiment, piscroside C significantly inhibited the expression of inflammatory cytokines (IL-6, IL-8 and IL-1ß) by inhibiting NF-κB activation, as resulting decrease in the phosphorylation of IKKß, IκBα and TAK1 in TNF-α-stimulated H292 cells. CONCLUSION: These findings indicate that piscroside C effectively inhibits inflammatory responses, which is an important process in the development of COPD through suppression of IKK/NF-κB activation. Our study suggest that piscroside C might represent a useful therapeutic for the treatment of inflammatory airway disease.