The anti-inflammatory activity of curcumin is mediated by its oxidative metabolites.

The spice turmeric, with its active polyphenol curcumin, has been used as anti-inflammatory remedy in traditional Asian medicine for centuries. Many cellular targets of curcumin have been identified, but how such a wide range of targets can be affected by a single compound is unclear. Here, we identified curcumin as a pro-drug that requires oxidative activation into reactive metabolites to exert anti-inflammatory activities. Synthetic curcumin analogs that undergo oxidative transformation potently inhibited the pro-inflammatory transcription factor nuclear factor κB (NF-κB), whereas stable, non-oxidizable analogs were less active, with a correlation coefficient (R2) of IC50versus log of autoxidation rate of 0.75. Inhibition of glutathione biosynthesis, which protects cells from reactive metabolites, increased the potency of curcumin and decreased the amount of curcumin-glutathione adducts in cells. Oxidative metabolites of curcumin adducted to and inhibited the inhibitor of NF-κB kinase subunit ß (IKKß), an activating kinase upstream of NF-κB. An unstable, alkynyl-tagged curcumin analog yielded abundant adducts with cellular protein that were decreased by pretreatment with curcumin or an unstable analog but not by a stable analog. Bioactivation of curcumin occurred readily in vitro, which may explain the wide range of cellular targets, but if bioactivation is insufficient in vivo, it may also help explain the inconclusive results in human studies with curcumin so far. We conclude that the paradigm of metabolic bioactivation uncovered here should be considered for the evaluation and design of clinical trials of curcumin and other polyphenols of medicinal interest.

Heptaphylline induces apoptosis in human colon adenocarcinoma cells through bid and Akt/NF-κB (p65) pathways.

Heptaphylline derivatives are carbazoles in Clausena harmandiana, a medicinal plant that is utilized for headache, stomach ache, and other treatments of illness. The present study examined the effects of heptaphylline and 7-methoxyheptaphylline on apoptosis of human colon adenocarcinoma cells (HT-29 cell line). Quantification of cell viability was performed using cell proliferation assay (MTT assay) and of protein expression through immunoblotting. The results showed that only heptaphylline, but not 7-methoxyheptaphylline, significantly significantly activated cleaved of caspase-3 and poly (ADP-ribose) polymerase (PARP-1) which resulted in HT-29 cell death. We found that heptaphylline activated BH3 interacting-domain death agonist (Bid) and Bak, proapoptotic proteins. In contrast, it suppressed X-linked inhibitor-of-apoptosis protein (XIAP), Bcl-xL and survivin, inhibitors of apoptosis. In addition, heptaphylline inhibited activation of NF-κB/p65 (rel), a regulator of apoptotic regulating proteins by suppressing the activation of Akt and IKKα, upstream regulators of p65. The findings suggested that heptaphylline induces apoptosis in human colon adenocarcinoma cells .

Anti-inflammatory effects and the underlying mechanisms of action of daidzein in murine macrophages stimulated with Prevotella intermedia lipopolysaccharide.

BACKGROUND AND OBJECTIVE: Host modulatory agents directed at inhibiting specific proinflammatory mediators could be beneficial in terms of attenuating periodontal disease progression and potentially enhancing therapeutic responses. The aim of this study was to investigate whether daidzein could modulate the production inflammatory mediators in macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease, and to delineate underlying mechanisms of action. MATERIAL AND METHODS: LPS was extracted from P. intermedia ATCC 25611 cells by the standard hot phenol-water method. The amounts of nitric oxide (NO) and interleukin-6 (IL-6) secreted into the culture medium were assayed. A real-time PCR was performed to quantify inducible nitric oxide synthase (iNOS) and IL-6 mRNA expression. We used immunoblot analysis to characterize iNOS protein expression, phosphrylation of c-Jun N-terminal kinase (JNK) and p38, degradation of inhibitory κB-α (IκB-α), nuclear translocation of nuclear factor-κB (NF-κB) subunits and phosphorylation of signal transducer and activator of transcription 1 (STAT1). The DNA-binding activity of NF-κB was assessed by using ELISA-based kits. RESULTS: Daidzein significantly inhibited the production of NO and IL-6, as well as their mRNA expression, in P. intermedia LPS-treated RAW264.7 cells. The JNK and p38 pathways were not involved in the regulation of LPS-induced NO and IL-6 release by daidzein. Daidzein inhibited the degradation of IκB-α induced by P. intermedia LPS. In addition, daidzein suppressed NF-κB transcriptional activity via regulation of the nuclear translocation and DNA-binding activity of NF-κB p50 subunit and blocked STAT1 phosphorylation. CONCLUSION: Although additional studies are required to dissect the molecular mechanism of action, our results suggest that daidzein could be a promising agent for treating inflammatory periodontal disease. Further research in animal models of periodontitis is necessary to better evaluate the potential of daidzein as a novel therapeutic agent to treat periodontal disease.

The Shaggy Inc Cap medicinal mushroom, Coprinus comatus (O.F.Mull.: Fr.) Pers. (Agaricomycetideae) substances interfere with H2O2 induction of the NF-kappaB pathway through inhibition of Ikappaalpha phosphorylation in MCF7 breast cancer cells.

Breast cancer is the most commonly diagnosed cancer among women. Currently, there is no effective therapy for malignant estrogen-independent breast cancer. In our study, we used hydrogen peroxide, a well-known strong oxidative reagent capable of activating the nuclear factor kappa B (NF-kappaB) transcription factor. The IC50 value of the culinary-medicinal Shaggy Inc Cap mushroom Coprinus comatus culture liquid crude extract on MCF7 cell viability was found to be as low as 76 microg/mL, and the IC50 value of C. comatus ethyl acetate extract was only 32 microg/ mL. Our results also showed that both extracts significantly affected IkappaBalpha phosphorylation in a dose-dependent manner. The effect of ethyl acetate extract was comparable to the effect of curcumin, a known NF-kappaB pathway inhibitor, and seemed to be the most active inhibitor of H2O2-dependent IkappaBalpha phosphorylation. In addition, the data obtained showed that only ethyl acetate extract inhibited the activity of IKK complex, at close to 90% as compared to the control of the untreated sample. These results suggest that C. comatus contains potent compounds capable of inhibiting NF-kappaB function and also possibly acts as an antitumor agent.

Butrin, isobutrin, and butein from medicinal plant Butea monosperma selectively inhibit nuclear factor-kappaB in activated human mast cells: suppression of tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8.

Activation of mast cells in rheumatoid synovial tissue has often been associated with tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 production and disease pathogenesis by adjacent cell types. Butea monosperma (BM) is a well known medicinal plant in India and the tropics. The aim of this study was to examine whether a standardized extract of BM flower (BME) could inhibit inflammatory reactions in human mast cells (HMC) using activated HMC-1 cells as a model. Four previously characterized polyphenols--butrin, isobutrin, isocoreopsin, and butein--were isolated from BME by preparative thin layer chromatography, and their purity and molecular weights were determined by liquid chromatography/mass spectrometry analysis. Our results showed that butrin, isobutrin, and butein significantly reduced the phorbol 12-myristate 13-acetate and calcium ionophore A23187-induced inflammatory gene expression and production of TNF-alpha, IL-6, and IL-8 in HMC-1 cells by inhibiting the activation of NF-kappaB. In addition, isobutrin was most potent in suppressing the NF-kappaB p65 activation by inhibiting IkappaBalpha degradation, whereas butrin and butein were relatively less effective. In vitro kinase activity assay revealed that isobutrin was a potent inhibitor of IkappaB kinase complex activity. This is the first report identifying the molecular basis of the reported anti-inflammatory effects of BME and its constituents butrin, isobutrin, and butein. The novel pharmacological actions of these polyphenolic compounds indicate potential therapeutic value for the treatment of inflammatory and other diseases in which activated mast cells play a role.

Induction of laryngeal cancer cell death by Ent-11-hydroxy-15-oxo-kaur-16-en-19-oic acid.

BACKGROUND: Ent-11-hydroxy-15-oxo-kaur-16-en-19-oic acid (5F) is known to exhibit antitumor activity, but its mechanism is not completely understood. 5F has not been tested in laryngeal cancer. METHODS: Two laryngeal cancer cell lines were treated with 5F. Cell death was analyzed by MTT [3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide] and Annexin V assay. Nuclear factor kappa beta (NF-κB)- and apoptosis-related molecules were examined. RESULTS: 5F induced laryngeal cancer cell death in a dose-dependent manner. The Annexin V assay and the measurement of cleavage of procaspase-3 and poly(ADP-ribose) polymerase demonstrated that the 5F-induced cell death was mainly apoptotic. 5F slightly reduced the basal level of NF-κB, but significantly suppressed the inducible NF-κB by reducing its transcriptional activity, protecting its inhibitory subunit IκBα from degradation, and suppressing its level in the nucleus. 5F also inhibited pro-proliferative and anti-apoptotic molecules but promoted pro-apoptotic Bax. CONCLUSIONS: 5F induces apoptosis of laryngeal cancer cells by inhibiting NF-κB activation/induction, suppressing pro-proliferative and anti-apoptotic molecules, and promoting pro-apoptotic Bax.

Berberine inhibits RANKL-induced osteoclast formation and survival through suppressing the NF-kappaB and Akt pathways.

Berberine, an isoquinoline alkaloid isolated from several medicinal plants, has been reported to possess anti-bacterial, anti-inflammatory and antitumor properties. Although berberine also inhibits osteoclastogenesis and bone resorption, the molecular machinery for its inhibitory effects remains unknown. This study focused on the suppressive effects of berberine on receptor activator of nuclear factor kappaB (NF-kappaB) ligand (RANKL)-induced osteoclastogenesis and survival. Berberine inhibited RANKL-mediated osteoclast formation and survival while having no cytotoxic effects on bone marrow macrophages or osteoblastic cells. Berberine attenuated RANKL-induced activation of NF-kappaB through inhibiting phosphorylation at the activation loop of IkappaBalpha kinase beta, phosphorylation and degradation of IkappaBalpha, and NF-kappaB p65 nuclear translocation. RANKL-induced Akt phosphorylation was strongly inhibited by berberine; however, neither monocyte/macrophage-colony stimulating factor (M-CSF)-induced nor insulin-induced Akt activation was inhibited by the drug. Under M-CSF- and RANKL-deprived condition, berberine increased the active form of caspase-3 in osteoclasts. By contrast, berberine did not potentiate the activation of caspase-3 in M-CSF-deprived bone marrow macrophages. These findings indicate that berberine inhibits osteoclast formation and survival through suppression of NF-kappaB and Akt activation and that both pathways in the osteoclast lineage are highly sensitive to berberine treatment.

Green tea polyphenols-induced apoptosis in human osteosarcoma SAOS-2 cells involves a caspase-dependent mechanism with downregulation of nuclear factor-kappaB.

Development of chemotherapy resistance and evasion from apoptosis in osteosarcoma, a primary malignant bone tumor, is often correlated with constitutive nuclear factor-kappaB (NF-kappaB) activation. Here, we investigated the ability of a polyphenolic fraction of green tea (GTP) that has been shown to have antitumor effects on various malignant cell lines to inhibit growth and induce apoptosis in human osteosarcoma SAOS-2 cells. Treatment of SAOS-2 cells with GTP (20-60 microg/ml) resulted in reduced cell proliferation and induction of apoptosis, which correlated with decreased nuclear DNA binding of NF-kappaB/p65 and lowering of NF-kappaB/p65 and p50 levels in the cytoplasm and nucleus. GTP treatment of cells reduced IkappaB-alpha phosphorylation but had no effect on its protein expression. Furthermore, GTP treatment resulted in the inhibition of IKK-alpha and IKK-beta, the upstream kinases that phosphorylate IkappaB-alpha. The increase in apoptosis in SAOS-2 cells was accompanied with decrease in the protein expression of Bcl-2 and concomitant increase in the levels of Bax. GTP treatment of SAOS-2 cells also resulted in significant activation of caspases as was evident by increased levels of cleaved caspase-3 and caspase-8 in these cells. Treatment of SAOS-2 cells with a specific caspase-3 inhibitor Ac-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO) and general caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (OMe)-fluoromethyl ketone (Z-VAD-FMK) rescued SAOS-2 cells from GTP-induced apoptosis. Taken together, these results indicate that GTP is a candidate therapeutic for osteosarcoma that mediates its antiproliferative and apoptotic effects via activation of caspases and inhibition of NF-kappaB.