Arzanol, a prenylated heterodimeric phloroglucinyl pyrone, inhibits eicosanoid biosynthesis and exhibits anti-inflammatory efficacy in vivo.

Based on its capacity to inhibit in vitro HIV-1 replication in T cells and the release of pro-inflammatory cytokines in monocytes, the prenylated heterodimeric phloroglucinyl α-pyrone arzanol was identified as the major anti-inflammatory and anti-viral constituent from Helichrysum italicum. We have now investigated the activity of arzanol on the biosynthesis of pro-inflammatory eicosanoids, evaluating its anti-inflammatory efficacy in vitro and in vivo. Arzanol inhibited 5-lipoxygenase (EC 7.13.11.34) activity and related leukotriene formation in neutrophils, as well as the activity of cyclooxygenase (COX)-1 (EC 1.14.99.1) and the formation of COX-2-derived prostaglandin (PG)E(2)in vitro (IC(50)=2.3-9μM). Detailed studies revealed that arzanol primarily inhibits microsomal PGE(2) synthase (mPGES)-1 (EC 5.3.99.3, IC(50)=0.4μM) rather than COX-2. In fact, arzanol could block COX-2/mPGES-1-mediated PGE(2) biosynthesis in lipopolysaccharide-stimulated human monocytes and human whole blood, but not the concomitant COX-2-derived biosynthesis of thromboxane B(2) or of 6-keto PGF(1α), and the expression of COX-2 or mPGES-1 protein was not affected. Arzanol potently suppressed the inflammatory response of the carrageenan-induced pleurisy in rats (3.6mg/kg, i.p.), with significantly reduced levels of PGE(2) in the pleural exudates. Taken together, our data show that arzanol potently inhibits the biosynthesis of pro-inflammatory lipid mediators like PGE(2)in vitro and in vivo, providing a mechanistic rationale for the anti-inflammatory activity of H. italicum, and a rationale for further pre-clinical evaluation of this novel anti-inflammatory lead

Ligustilide: a novel TRPA1 modulator

TRPA1 is activated by electrophilic compounds such as mustard oil (MO). Here, we demonstrate a bimodal sensitivity of TRPA1 to ligustilide (Lig), an electrophilic volatile dihydrophthalide of dietary and medicinal relevance. Lig is a potent TRPA1 activator and is also capable to induce a modest block of MO activated currents. Aromatization to dehydroligustilide (DH-Lig), as occurs during aging of its botanical sources, reversed this profile, enhancing TRPA1 inhibition and reducing activation. Mutation of the reactive cysteines in mouseTRPA1 (C622S, C642S, C666S) dramatically reduced activation by MO and significantly reduced that by Lig, but had an almost negligible effect on the action of DH-Lig, whose activation mechanism of TRPA1 is therefore largely independent from the alkylation of cysteine residues. Taken together, these observations show that the phthalide structural motif is a versatile platform to investigate the modulation of TRPA1 by small molecules, being tunable in terms of activation/inhibition profile and mechanism of interaction. Finally, the action of Lig on TRPA1 may contribute to the gustatory effects of celery, its major dietary source, and to the pharmacological action of important plants from the Chinese and native American traditional medicines.status: publishe

PP272—Migraine and parthenolide inhibition of transient receptor potential ankyrin 1

2013 e103 emerged as a major complication of bortezomib therapy, which usually appears in the first courses of therapy with a number of sensory and painful symptoms, including reduced threshold to mechanical and cold stimuli. No satisfactory explanation or effective treatment exists for bortezomib-evoked CIPN. Patients (or Materials) and Methods: In this study, we evaluated whether TRPA1 acted as a critical mediator of CIPN by bortezomib or oxaliplatin in a mouse model system. Results: Our data demonstrated that CIPN hypersensitivity phenotype that was stably established by bortezomib could be transiently reverted by systemic or local treatment with the TRPA1 antagonist HC-030031. A similar effect was produced by the oxidative stress scavenger α -lipoic acid. Notably, the CIPN phenotype was abolished completely in mice that were genetically deficient in TRPA1, highlighting its essential role. Administration of bortezomib or oxaliplatin, which also elicits TRPA1-dependent hypersensitivity, produced a rapid, transient increase in plasma of carboxy-methyllysine, a byproduct of oxidative stress. Short-term systemic treatment with either HC-030031 or α -lipoic acid could completely prevent hypersensitivity if administered before the cytotoxic drug. Conclusion: Our findings highlight a key role for early activation/ sensitization of TRPA1 by oxidative stress by-products in producing CIPN. Furthermore, they suggest prevention strategies for CIPN in patients through the use of early, short-term treatments with TRPA1 antagonists. Disclosure of Interest: None declared

Targeting oncogenic serine/threonine-protein kinase BRAF in cancer cells inhibits angiogenesis and abrogates hypoxia

Carcinomas are comprised of transformed epithelial cells that are supported in their growth by a dedicated neovasculature. How the genetic milieu of the epithelial compartment influences tumor angiogenesis is largely unexplored. Drugs targeted to mutant cancer genes may act not only on tumor cells but also, directly or indirectly, on the surrounding stroma. We investigated the role of the BRAF(V600E) oncogene in tumor/vessel crosstalk and analyzed the effect of the BRAF inhibitor PLX4720 on tumor angiogenesis. Knock-in of the BRAF(V600E) allele into the genome of human epithelial cells triggered their angiogenic response. In cancer cells harboring oncogenic BRAF, the inhibitor PLX4720 switches off the ERK pathway and inhibits the expression of proangiogenic molecules. In tumor xenografts harboring the BRAF(V600E), PLX4720 extensively modifies the vascular network causing abrogation of hypoxia. Overall, our results provide a functional link between oncogenic BRAF and angiogenesis. Furthermore, they indicate how the tumor vasculature can be “indirectly” besieged through targeting of a genetic lesion to which the cancer cells are addicted

Application of Hansch’s Model to Capsaicinoids and Capsinoids: A Study Using the Quantitative Structure−Activity Relationship. A Novel Method for the Synthesis of Capsinoids

We describe a synthetic approach for two families of compounds, the capsaicinoids and capsinoids, as part of a study of the quantitative relationship between structure and activity