Characterization of Anti-Inflammatory and Antioxidant Constituents from Scutellaria baicalensis Using LC-MS Coupled with a Bioassay Method.

An effective and previously demonstrated screening method for active constituents in natural products using LC-MS coupled with a bioassay was reported in our earlier studies. With this, the current investigation attempted to identify bioactive constituents of Scutellaria baicalensis through LC-MS coupled with a bioassay. Peaks at broadly 17-20 and 24-25 min on the MS chromatogram displayed an inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. Similarly, peaks at roughly 17-19 and 22 min showed antioxidant activity with an 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)/2,2-diphenyl-1- picrylhydrazyl (DPPH) assay. For confirmation of LC-MS coupled with a bioassay, nine compounds (1-9) were isolated from an MeOH extract of S. baicalensis. As we predicted, compounds 1, 8, and 9 significantly reduced lipopolysaccharide (LPS)-induced NO production in BV2 cells. Likewise, compounds 5, 6, and 8 exhibited free radical-scavenging activities with the ABTS/DPPH assay. In addition, the structural similarity of the main components was confirmed by analyzing the total extract and EtOAc fractions through molecular networking. Overall, the results suggest that the method comprised of LC-MS coupled with a bioassay can effectively predict active compounds without an isolation process, and the results of molecular networking predicted that other components around the active compound node may also be active.

In vitro synergistic effect of retapamulin with erythromycin and quinupristin against Enterococcus faecalis.

To find a therapeutic alternative for the treatment of skin and soft tissue infections, we evaluated the effects of combinations of retapamulin with macrolide, lincosamide, and streptogramin (MLS) antibiotics against Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecium, and Enterococcus faecalis. Using both the disk diffusion test and checkerboard assay, we initially examined the effects of combinations of retapamulin with MLS antibiotics against standard strains of these species. Combinations of retapamulin with erythromycin, quinupristin/dalfopristin and quinupristin showed synergistic activity against E. faecalis only. Synergy of retapamulin with clindamycin and dalfopristin was not observed. Then, a checkerboard assay was performed to evaluate the effects of the combinations against 15 clinical strains of E. faecalis. Retapamulin and quinupristin, the most synergistic combination, showed activity against all erythromycin-susceptible, -intermediate, and -resistant strains tested. Among the eight strains with high-level erythromycin resistance, five strains were synergistically inhibited in the presence of only 1 µg of retapamulin per ml. Time-kill assay revealed that combinations of retapamulin with erythromycin and quinupristin were bacteriostatic. These results suggest that combinations of retapamulin with erythromycin and quinupristin have in vitro synergistic activity against E. faecalis, including strains with high-level erythromycin resistance.

Minecoside Modulates Cell Invasion via Regulation of CXCR4 Expression in Breast and Colon Cancer Cells.

Metastasis, which is closely linked to cancer-related deaths, is a highly complex process. It is an organ-specific process and involves interactions between the host and cancer cells. CXC chemokine receptor 4 is known to be expressed in various tumors and the binding with CXC ligand 12 induces signaling in cancer cell survival, migration, and proliferation. Particularly, the CXC chemokine receptor 4/CXC ligand 12 axis is known to promote the metastasis of breast cancer. Thus, agents that can downregulate CXC chemokine receptor 4 expression have potential against cancer metastasis. Minecoside is an active compound extracted from Veronica peregrina L. It is widely distributed in Korea and has been used as a traditional drug for the treatment of various chronic diseases. However, the anticancer and anti-inflammatory effects of minecoside have yet to be clarified. In this study, we found that minecoside downregulates constitutive CXC chemokine receptor 4 expression in MDA-MB-231 breast cancer cells. This downregulation also occurred at the transcriptional level. Minecoside-mediated suppression of CXC chemokine receptor 4 expression inhibited CXC ligand 12-induced invasion of breast and colorectal cancer cells. Overall, our results suggest that minecoside can be a novel anticancer agent that can inhibit cancer metastasis through inhibition of CXC chemokine receptor 4 expression.

Icariin abrogates osteoclast formation through the regulation of the RANKL-mediated TRAF6/NF-κB/ERK signaling pathway in Raw264.7 cells.

BACKGROUND: Icariin is pharmacologically active prenylated flavonoid glycoside that has various biologic effects such as antioxidant, anticancer, and anti-inflammatory activities. In addition, icariin has been used in Chinese medicine for thousands of years to treat osteoporosis and it is still being used today. However, direct mechanism of icariin in the treatment of bone disease is not understood. PURPOSE: The purpose of this study is to investigate whether icariin influences RANKL-induced osteoclast formation in murine macrophages. METHODS: Osteoclastogenesis was determined by TRAP staining and activity assay. Inhibition of signaling pathways and marker protein expression were evaluated by western blot analysis. The NF-κB (p65) nuclear localization was detected by immunofluorescence assay, and NF-κB/DNA-binding activity was detected by electrophoretic mobility shift assay (EMSA). RESULTS: In our study, icariin inhibited the differentiation of pre-osteoclast cells into osteoclasts and suppressed expression of various genes involved in osteoclast formation and bone resorption. Also, icariin blocked the osteoclastogenesis induced by MCF7 and MDA-MB-231 breast cancer cells through inhibition of NF-κB activation. We found that icariin inhibited RANKL-stimulated TRAF-6 expression, and subsequently suppressed the phosphorylation of ERK, but icariin did not show an effect on p38, JNK, and Akt activation. CONCLUSION: These results indicate that icariin is likely to be a candidate for bone-related disease treatment and that icariin provides insights into the molecular mechanisms that influence RANKL-induced osteoclast differentiation.

Allergen­removed Rhus verniciflua Stokes suppresses invasion and migration of pancreatic cancer cells through downregulation of the JAK/STAT and Src/FAK signaling pathways.

Pancreatic cancer is a leading cause of mortality and morbidity worldwide. Due to drug resistance, and the high toxicity and adverse side effects of existing chemotherapeutic drugs, the current treatment of highly aggressive pancreatic cancer is considered inadequate. Allergen­removed Rhus verniciflua Stokes (aRVS) has a strong antiproliferative effect in various cancer cells, and due to its low toxicity, it has emerged as an attractive candidate for cancer treatment. However, the potential use of aRVS as a treatment for pancreatic cancer is relatively unexplored. The present study examined the effects of aRVS on the invasion and migration of pancreatic cancer cells, and identified the molecular mechanisms underlying its anticancer effects. aRVS inhibited the Janus kinase/signal transducer and activator of transcription pathway in pancreatic cancer cells, and decreased the protein expression of mucin 4. In addition, it inhibited the activation of focal adhesion kinase and Src signaling, and decreased the expression of matrix metalloproteinase 9, which may reduce the migration and invasion of pancreatic cancer cells. In conclusion, the present study suggested that aRVS may be a potential treatment for aggressive pancreatic cancer.

Characterization of inhibitory constituents of NO production from Catalpa ovata using LC-MS coupled with a cell-based assay.

An effective screening method for inhibitors of NO production in natural products using LC-QTOF MS/MS coupled with a cell-based assay was proposed. The ethyl acetate fraction of Catalpa ovata exhibited a strong inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. We attempted to identify the active constituents of C. ovata by using LC-QTOF MS/MS coupled with a cell-based assay. Peaks at approximately 14-15 min on the MS chromatogram were estimated to be the bioactive constituents. A new iridoid compound, 6-O-trans-feruloyl-3ß-hydroxy-7-deoxyrehamaglutin A (4), and nine known compounds (1-3, 5-10) were isolated from the ethyl acetate fraction of C. ovata by repeated column chromatography. Compounds 3, 4, 5, 7, and 8 significantly attenuated lipopolysaccharide-stimulated NO production in BV2 cells. Our results indicate that LC-QTOF MS/MS coupled with a cell-based NO production inhibitory assay successfully predicted active compounds without a time-consuming isolation process.

Screening and identification of neuroprotective compounds from Scrophularia buergeriana using cell extraction coupled with LC-MS.

In the cell extraction_LC-MS method, when cells are incubated with natural product extracts, bioactive compounds selectively bind to extracellular or intracellular targets. The extracts and major compounds (phenylpropanoids and iridoid glycosides) of Scrophularia buergeriana Miquel have been reported to show neuroprotective effects both in vitro and in vivo. In this study, the cell extraction_LC-MS strategy was applied to screen and identify potential neuroprotective compounds from S. buergeriana by using immortalized mouse hippocampal HT22 cells. The results showed that two known compounds from S. buergeriana selectively bound HT22 cells. Additionally, metabolomics analyses were performed using the Mass Profiler Professional and Limma differential expression package of R to identify significant differences between HT22 cells treated with S. buergeriana and untreated cells. The cell extraction approach more accurately reflects in vivo conditions compared with other methods and can be readily used for screening bioactive components from natural products.

Triptolide blocks the STAT3 signaling pathway through induction of protein tyrosine phosphatase SHP-1 in multiple myeloma cells.

Triptolide, an active component extracted from the medicinal plant Tripterygium wilfordii Hook F., has been used to treat various diseases, including lupus, cancer, rheumatoid arthritis and nephritic syndrome. The present study investigated the effects of triptolide on multiple myeloma using western blotting and an electrophoretic mobility shift assay. Triptolide was found to suppress the inducible and constitutive activation of signal transducer and activator of transcription 3 (STAT3), which is closely associated with inflammation and tumorigenesis. Triptolide also inhibited the DNA binding of STAT3. This correlated with the downregulation of Src kinase and Janus kinase 1 and 2, and with the upregulation of protein tyrosine phosphatase non­receptor type 6 (also known as SHP­1). In addition, triptolide downregulated the expression of the STAT3­regulated antiapoptotic (Bcl­xL and myeloid cell leukemia­1), proliferative (cyclin D1), and angiogenic (vascular endothelial growth factor) genes, suggesting that triptolide can induce apoptosis of tumor cells. These results suggest that triptolide may be a potential therapeutic anticancer agent for the prevention and treatment of multiple myeloma; thus further in­depth investigations into its efficacy and toxicity are warranted.

Onbaekwon Suppresses Colon Cancer Cell Invasion by Inhibiting Expression of the CXC Chemokine Receptor 4.

Cysteine X cysteine (CXC) chemokine receptor 4 (CXCR4) and C-X-C motif chemokine 12 (CXCL12) were originally identified as chemoattractants between immune cells and sites of inflammation. Since studies have validated an increased level of CXCL12 and its receptor in patients with colorectal cancers, CXCL12/CXCR4 axis has been considered as a valuable marker of cancer metastasis. Therefore, identification of CXCR4 inhibitors has great potential to abrogate tumor metastasis. Onbaekwon (OBW) is a complex herbal formula that is derived from the literature of traditional Korean medicine Dongeuibogam. In this study, we demonstrated that OBW suppressed CXCR4 expression in various cancer cell types in a concentration- and time-dependent manner. Both proteasomal and lysosomal inhibitors had no effect to prevent the OBW-induced suppression of CXCR4, suggesting that the inhibitory effect of OBW was not due to proteolytic degradation but occurred at the transcriptional level. Electrophoretic mobility shift assay further confirmed that OBW could block endogenous activation of nuclear factor kappa B, a key transcription factor that regulates the expression of CXCR4 in colon cancer cells. Consistent with the aforementioned molecular basis, OBW abolished cell invasion induced by CXCL12 in colon cancer cells. Together, our results suggest that OBW, as a novel inhibitor of CXCR4, could be a promising therapeutic agent contributing to cancer treatment.

Pomolic acid suppresses HIF1α/VEGF-mediated angiogenesis by targeting p38-MAPK and mTOR signaling cascades.

BACKGROUND: Pomolic acid (PA), an active triterpenoid from Euscaphis japonica, inhibits the proliferation of a variety of cancer cells, but the molecular mechanisms of the anti-angiogenic potential of PA have not been fully elucidated in breast cancer cells. HYPOTHESIS/PURPOSE: We investigated the molecular mechanisms underlying the anti-angiogenic effect of PA in epidermal growth factor (EGF)-responsive human breast cancer cells, MCF-7 and MDA-MB-231, and human umbilical vascular endothelial cells (HUVEC). STUDY DESIGN/METHODS: Effects of PA on EGF-induced HIF1α/VEGF expression in MCF-7, MDA-MB-231 and HUVEC were assayed. As to the mechanisms, EGF-mediated MAPKs, PI3K/Akt, and mTOR signaling pathway were performed. Wound healing and invasion assay, tube formation assay, immunoblot assay, real-time PCR, luciferase gene assay, electrophoretic mobility shift assay and immunofluorescence staining were used for assessment. RESULTS: PA significantly and selectively suppressed EGF-induced HIF1α/VEGF expression, whereas it did not affect the expression of HIF1ß in MCF-7 and MDA-MB-231. Furthermore, PA inhibited EGF-induced angiogenesis in vitro and downregulated HIF1α/VEGF expression in HUVEC. Mechanistically, we found that the inhibitory effects of PA on HIF1α/VEGF expression are associated with inhibition of HIF1α/VEGF expression through an EGF-dependent mechanism. In addition, PA suppressed the EGF-induced phosphorylation of p38-MAPK and mTOR. CONCLUSION: PA suppresses EGF-induced HIF1α protein translation by inhibiting the p38-MAPK and mTOR kinase signaling pathways and plays a novel anti-angiogenic role.

Optimization of pancreatic lipase inhibitory and antioxidant activities of Ilex paraguariensis by using response surface methodology.

Response surface methodology (RSM) using a Box-Behnken design was used to optimize the extraction conditions for obtaining pancreatic lipase inhibitory and antioxidant principles from Ilex paraguariensis leaves. Three influencing factors: extraction time (min), the liquid-solid ratio, and ethanol concentration (%, v/v) were investigated in the ultrasonic extraction process. Optimization of the extraction conditions to obtain a product with minimum PL activity, maximum antioxidant activity, and maximum yield was performed using RSM by focusing on the three target influencing factors. The optimum conditions were established as the ethanol concentration (54.8 %), liquid-solid ratio (35.4), and extraction time (70.0 min). Under these conditions, the 2,2-diphenyl-1-picrylhydrazyl scavenging activity, PL activity, extraction yield were 59.3 ± 3.5, 35.3 ± 3.0, and 34.4 ± 0.4 %, respectively, similar to the theoretical predicted values of 59.7, 35.2, and 34.3 %, respectively.

Hispolon from Phellinus linteus induces apoptosis and sensitizes human cancer cells to the tumor necrosis factor-related apoptosis-inducing ligand through upregulation of death receptors.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent anticancer agent possessing the ability to induce apoptosis in various cancer cells but not in non­malignant cells. However, certain type of cancer cells are resistant to TRAIL­induced apoptosis and some acquire resistance after the first treatment. So development of an agent that can reduce or avoid resistance in TRAIL­induced apoptosis has garnered significant attention. The present study evaluated the anticancer potential of hispolon in TRAIL­induced apoptosis and indicated hispolon can sensitize cancer cells to TRAIL. As the mechanism of action was examined, hispolon was found to activate caspase­3, caspase­8 and caspase­9, while downregulating the expression of cell survival proteins such as cFLIP, Bcl­2 and Bcl­xL and upregulating the expression of Bax and truncated Bid. We also found hispolon induced death receptors in a non­cell type­specific manner. Upregulation of death receptors by hispolon was found to be p53-independent but linked to the induction of CAAT enhancer binding protein homologous protein (CHOP). Overall, hispolon was demonstrated to potentiate the apoptotic effects of TRAIL through downregulation of anti­apoptotic proteins and upregulation of death receptors linked with CHOP and pERK elevation.

SB365, Pulsatilla saponin D, suppresses the growth of gefitinib-resistant NSCLC cells with Met amplification.

Clinical treatment using epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib or erlotinib has been applied in patients with non-small cell lung cancers (NSCLCs). Unfortunately, acquired drug resistance emerges in these patients due to the amplification of the Met proto-oncogene, which may be a compensatory mechanism of NSCLCs against EGFR inhibition. To overcome this resistance, identification of new small-molecule natural compounds is crucial for cancer therapeutics. In this regard, SB365, saponin D from the root of Pulsatilla koreana which has been used as a traditional medicine in Korea for several diseases, has attracted wide interest. In the present study, SB365 effectively suppressed the proliferation of gefitinib-resistant HCC827GR NSCLC cells with Met amplification. Notably, our data revealed that SB365 inhibited the phosphorylation of Met and the downstream signaling pathway required for growth and survival in the Met-amplified HCC827GR cells. Moreover, SB365 suppressed the anchorage-independent growth, migration and invasion along with induction of apoptosis in the HCC827GR cells. Therefore, these results suggest that SB365 is good candidate as a natural product for use in the treatment of Met-amplified NSCLCs.

Upsides and downsides of reactive oxygen species for cancer: the roles of reactive oxygen species in tumorigenesis, prevention, and therapy.

SIGNIFICANCE: Extensive research during the last quarter century has revealed that reactive oxygen species (ROS) produced in the body, primarily by the mitochondria, play a major role in various cell-signaling pathways. Most risk factors associated with chronic diseases (e.g., cancer), such as stress, tobacco, environmental pollutants, radiation, viral infection, diet, and bacterial infection, interact with cells through the generation of ROS. RECENT ADVANCES: ROS, in turn, activate various transcription factors (e.g., nuclear factor kappa-light-chain-enhancer of activated B cells [NF-κB], activator protein-1, hypoxia-inducible factor-1α, and signal transducer and activator of transcription 3), resulting in the expression of proteins that control inflammation, cellular transformation, tumor cell survival, tumor cell proliferation and invasion, angiogenesis, and metastasis. Paradoxically, ROS also control the expression of various tumor suppressor genes (p53, Rb, and PTEN). Similarly, γ-radiation and various chemotherapeutic agents used to treat cancer mediate their effects through the production of ROS. Interestingly, ROS have also been implicated in the chemopreventive and anti-tumor action of nutraceuticals derived from fruits, vegetables, spices, and other natural products used in traditional medicine. CRITICAL ISSUES: These statements suggest both "upside" (cancer-suppressing) and "downside" (cancer-promoting) actions of the ROS. Thus, similar to tumor necrosis factor-α, inflammation, and NF-κB, ROS act as a double-edged sword. This paradox provides a great challenge for researchers whose aim is to exploit ROS stress for the development of cancer therapies. FUTURE DIRECTIONS: the various mechanisms by which ROS mediate paradoxical effects are discussed in this article. The outstanding questions and future directions raised by our current understanding are discussed.

Zyflamend sensitizes tumor cells to TRAIL-induced apoptosis through up-regulation of death receptors and down-regulation of survival proteins: role of ROS-dependent CCAAT/enhancer-binding protein-homologous protein pathway.

AIM: TNF (tumor necrosis factor)-related apoptosis-inducing ligand (TRAIL), is a selective killer of tumor cells, although its potential is limited by the development of resistance. In this article, we investigated whether the polyherbal preparation Zyflamend(®) can sensitize tumor cells to TRAIL. RESULTS: We found that Zyflamend potentiated TRAIL-induced apoptosis in human cancer cells. Zyflamend manifested its effects through several mechanisms. First, it down-regulated the expression of cell survival proteins known to be linked to resistance to TRAIL. Second, Zyflamend up-regulated the expression of pro-apoptotic protein, Bax. Third, Zyflamend up-regulated the expression of death receptors (DRs) for TRAIL. Up-regulation of DRs was critical as gene-silencing of these receptors significantly reduced the effect of Zyflamend on TRAIL-induced apoptosis. The up-regulation of DRs was dependent on CCAAT/enhancer-binding protein-homologous protein (CHOP), as Zyflamend induced CHOP, its gene-silencing abolished the induction of receptors, and mutation of the CHOP binding site on DR5 promoter abolished Zyflamend-mediated DR5 transactivation. Zyflamend mediated its effects through reactive oxygen species (ROS), as ROS quenching reduced its effect. Further, Zyflamend induced DR5 and CHOP and down-regulated the expression of cell survival proteins in nude mice bearing human pancreatic cancer cells. INNOVATION: Zyflamend can sensitize tumor cells to TRAIL through modulation of multiple cell signaling mechanisms that are linked to ROS. CONCLUSION: Zyflamend potentiates TRAIL-induced apoptosis through the ROS-CHOP-mediated up-regulation of DRs, increase in pro-apoptotic protein and down-regulation of cell survival proteins.

Turmeric (Curcuma longa) inhibits inflammatory nuclear factor (NF)-κB and NF-κB-regulated gene products and induces death receptors leading to suppressed proliferation, induced chemosensitization, and suppressed osteoclastogenesis.

SCOPE: The incidence of cancer is significantly lower in regions where turmeric is heavily consumed. Whether lower cancer incidence is due to turmeric was investigated by examining its effects on tumor cell proliferation, on pro-inflammatory transcription factors NF-κB and STAT3, and on associated gene products. METHODS AND RESULTS: Cell proliferation and cell cytotoxicity were measured by the MTT method, NF-κB activity by EMSA, protein expression by Western blot analysis, ROS generation by FACS analysis, and osteoclastogenesis by TRAP assay. Turmeric inhibited NF-κB activation and down-regulated NF-κB-regulated gene products linked to survival (Bcl-2, cFLIP, XIAP, and cIAP1), proliferation (cyclin D1 and c-Myc), and metastasis (CXCR4) of cancer cells. The spice suppressed the activation of STAT3, and induced the death receptors (DR)4 and DR5. Turmeric enhanced the production of ROS, and suppressed the growth of tumor cell lines. Furthermore, turmeric sensitized the tumor cells to chemotherapeutic agents capecitabine and taxol. Turmeric was found to be more potent than pure curcumin for cell growth inhibition. Turmeric also inhibited NF-κB activation induced by RANKL that correlated with the suppression of osteoclastogenesis. CONCLUSION: Our results indicate that turmeric can effectively block the proliferation of tumor cells through the suppression of NF-κB and STAT3 pathways.

Boswellic acid suppresses growth and metastasis of human pancreatic tumors in an orthotopic nude mouse model through modulation of multiple targets.

Pancreatic cancer (PaCa) is one of the most lethal cancers, with an estimated 5-year survival of <5% even when patients are given the best treatment available. In addition, these treatments are often toxic and expensive, thus new agents which are safe, affordable and effective are urgently needed. We describe here the results of our study with acetyl-11-keto-ß-boswellic acid (AKBA), an agent obtained from an Ayurvedic medicine, gum resin of Boswellia serrata. Whether AKBA has an activity against human PaCa, was examined in in vitro models and in an orthotopic nude mouse model of PaCa. We found that AKBA inhibited the proliferation of four different PaCa cell lines (AsPC-1, PANC-28, and MIA PaCa-2 with K-Ras and p53 mutations, and BxPC-3 with wild-type K-Ras and p53 mutation). These effects correlated with an inhibition of constitutively active NF-κB and suppression of NF-κB regulating gene expression. AKBA also induced apoptosis, and sensitized the cells to apoptotic effects of gemcitabine. In the orthotopic nude mouse model of PaCa, p.o. administration of AKBA alone (100 mg/kg) significantly inhibited the tumor growth; this activity was enhanced by gemcitabine. In addition, AKBA inhibited the metastasis of the PaCa to spleen, liver, and lungs. This correlated with decreases in Ki-67, a biomarker of proliferation, and CD31, a biomarker of microvessel density, in the tumor tissue. AKBA produced significant decreases in the expression of NF-κB regulating genes in the tissues. Immunohistochemical analysis also showed AKBA downregulated the expression of COX-2, MMP-9, CXCR4, and VEGF in the tissues. Overall these results demonstrate that AKBA can suppress the growth and metastasis of human pancreatic tumors in an orthotopic nude mouse model that correlates with modulation of multiple targets.

Identification of novel anti-inflammatory agents from Ayurvedic medicine for prevention of chronic diseases: "reverse pharmacology" and "bedside to bench" approach.

Inflammation, although first characterized by Cornelius Celsus, a physician in first Century Rome, it was Rudolf Virchow, a German physician in nineteenth century who suggested a link between inflammation and cancer, cardiovascular diseases, diabetes, pulmonary diseases, neurological diseases and other chronic diseases. Extensive research within last three decades has confirmed these observations and identified the molecular basis for most chronic diseases and for the associated inflammation. The transcription factor, Nuclear Factor-kappaB (NF-kappaB) that controls over 500 different gene products, has emerged as major mediator of inflammation. Thus agents that can inhibit NF-kappaB and diminish chronic inflammation have potential to prevent or delay the onset of the chronic diseases and further even treat them. In an attempt to identify novel anti-inflammatory agents which are safe and effective, in contrast to high throughput screen, we have turned to "reverse pharmacology" or "bed to benchside" approach. We found that Ayurveda, a science of long life, almost 6,000 years old, can serve as a "goldmine" for novel anti-inflammatory agents used for centuries to treat chronic diseases. The current review is an attempt to provide description of various Ayurvedic plants currently used for treatment, their active chemical components, and the inflammatory pathways that they inhibit.

Celastrol, a triterpene, enhances TRAIL-induced apoptosis through the down-regulation of cell survival proteins and up-regulation of death receptors.

Whether celastrol, a triterpene from traditional Chinese medicine, can modulate the anticancer effects of TRAIL, the cytokine that is currently in clinical trial, was investigated. As indicated by assays that measure plasma membrane integrity, phosphatidylserine exposure, mitochondrial activity, and activation of caspase-8, caspase-9, and caspase-3, celastrol potentiated the TRAIL-induced apoptosis in human breast cancer cells, and converted TRAIL-resistant cells to TRAIL-sensitive cells. When examined for its mechanism, we found that the triterpene down-regulated the expression of cell survival proteins including cFLIP, IAP-1, Bcl-2, Bcl-xL, survivin, and XIAP and up-regulated Bax expression. In addition, we found that celastrol induced the cell surface expression of both the TRAIL receptors DR4 and DR5. This increase in receptors was noted in a wide variety of cancer cells including breast, lung, colorectal, prostate, esophageal, and pancreatic cancer cells, and myeloid and leukemia cells. Gene silencing of the death receptor abolished the effect of celastrol on TRAIL-induced apoptosis. Induction of the death receptor by the triterpenoid was found to be p53-independent but required the induction of CAAT/enhancer-binding protein homologous protein (CHOP), inasmuch as gene silencing of CHOP abolished the induction of DR5 expression by celastrol and associated enhancement of TRAIL-induced apoptosis. We found that celastrol also induced reactive oxygen species (ROS) generation, and ROS sequestration inhibited celastrol-induced expression of CHOP and DR5, and consequent sensitization to TRAIL. Overall, our results demonstrate that celastrol can potentiate the apoptotic effects of TRAIL through down-regulation of cell survival proteins and up-regulation of death receptors via the ROS-mediated up-regulation of CHOP pathway.