Tamara P. Kondratyuk

Cytokine expression in normal and inflamed esophageal mucosa: a study into the pathogenesis of allergic eosinophilic esophagitis.

Objectives: We studied the expression of cytokines and inflammatory cells in normal and inflamed esophageal mucosa of children with the aim of furthering our understanding of the pathophysiology of allergic eosinophilic esophagitis (AEE). Methods: Controls and AEE patients (≥15 eosinophils/high-power field on esophageal mucosal biopsies) between the ages of 1 and 18 years were recruited. Esophageal biopsies were obtained for histologic examination, immunohistochemical studies, and cytokine analysis. Results: Eight controls (4 males; mean age 9.99 years) and 11 AEE patients (8 males; mean age 7.15 years) were studied. mRNA expression of interferon (IFN)-γ, interleukin (IL)-4, IL-5, IL-13, eotaxin-1, eotaxin-2, eotaxin-3, and RANTES was studied. IFN-γ and IL-5 expressions were significantly up-regulated in AEE patients compared with controls. Expressions of IL-4 and IL-13 were similar between AEE patients and controls. Eotaxin-1 expression was significantly up-regulated in AEE patients, whereas eotaxin-2 was up-regulated in controls. Expression of RANTES and eotaxin-3 was similar between the two groups. There was increased staining for mast cells in AEE patients compared with controls. Conclusions: Our data suggests that AEE is primarily an IL-5 selective TH2 response, with a possible TH1 component, and a differential role of eosinophilic chemoattractants. The role of mast cells in the pathogenesis of AEE needs additional study.

Selective synthesis and biological evaluation of sulfate-conjugated resveratrol metabolites.

Five resveratrol sulfate metabolites were synthesized and assessed for activities known to be mediated by resveratrol: inhibition of tumor necrosis factor (TNF) alpha induced NFkappaB activity, cylcooxygenases (COX-1 and COX-2), aromatase, nitric oxide production in endotoxin-stimulated macrophages, proliferation of KB or MCF7 cells, induction of quinone reductase 1 (QR1), accumulation in the sub-G(1) phase of the cell cycle, and quenching of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. Two metabolites showed activity in these assays; the 3-sulfate exhibited QR1 induction, DPPH free radical scavenging, and COX-1 and COX-2 inhibitory activities and the 4-sulfate inhibited NFkappaB induction, as well as COX-1 and COX-2 activities. Resveratrol and its 3-sulfate and 4-sulfate inhibit NO production by NO scavenging and down-regulation of iNOS expression in RAW 264.7 cells. Resveratrol sulfates displayed low antiproliferative activity and negligible uptake in MCF7 cells.

Natural Product Polyphenols of Relevance to Human Health

Polyphenols are widely distributed in the plant kingdom and represent an abundant antioxidant component of the human diet. The review offers a brief description of the chemistry and occurrence in plant food of four important groups of polyphenols: phenolic acids, flavonoids, stilbenes, and lignans. Interest in the possible health benefits of polyphenols has increased due to corresponding antioxidant capacity. Considerable evidence is now available showing anticarcinogenic effects of polyphenolic compounds, as well as potential to prevent cardiovascular and cerebrovascular diseases. The use of botanicals has received a large amount of attention in recent years. Epidemiological studies have shown that a reduced risk of cancer is associated with diets rich in vegetables and fruits, and methods for the discovery and characterization of active compounds from plant sources are available. These results are promising, but additional research on the molecular mechanism of action of polyphenols and their application to human health is required.

Novel Marine Phenazines as Potential Cancer Chemopreventive and Anti-Inflammatory Agents

Two new (1 and 2) and one known phenazine derivative (lavanducyanin, 3) were isolated and identified from the fermentation broth of a marine-derived Streptomyces sp. (strain CNS284). In mammalian cell culture studies, compounds 1, 2 and 3 inhibited TNF-α-induced NFκB activity (IC50 values of 4.1, 24.2, and 16.3 μM, respectively) and LPS-induced nitric oxide production (IC50 values of >48.6, 15.1, and 8.0 μM, respectively). PGE2 production was blocked with greater efficacy (IC50 values of 7.5, 0.89, and 0.63 μM, respectively), possibly due to inhibition of cyclooxygenases in addition to the expression of COX-2. Treatment of cultured HL-60 cells led to dose-dependent accumulation in the subG1 compartment of the cell cycle, as a result of apoptosis. These data provide greater insight on the biological potential of phenazine derivatives, and some guidance on how various substituents may alter potential anti-inflammatory and anti-cancer effects.

Arenamides A−C, Cytotoxic NFκB Inhibitors from the Marine Actinomycete Salinispora arenicola⊥

Three new cyclohexadepsipeptides, arenamides A-C (1-3), were isolated from the fermentation broth of a marine bacterial strain identified as Salinispora arenicola. The planar structures of these compounds were assigned by detailed interpretation of NMR and MS/MS spectroscopic data. The absolute configurations of the amino acids, and those of the chiral centers on the side chain, were established by application of the Marfey and modified Mosher methods. The effect of arenamides A and B on NFkappaB activity was studied with stably transfected 293/NFkappaB-Luc human embryonic kidney cells induced by treatment with tumor necrosis factor (TNF). Arenamides A (1) and B (2) blocked TNF-induced activation in a dose- and time-dependent manner with IC(50) values of 3.7 and 1.7 microM, respectively. In addition, the compounds inhibited nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production with lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Moderate cytotoxicity was observed with the human colon carcinoma cell line HCT-116, but no cytotoxic effect was noted with cultured RAW cells. Taken together, these data suggest that the chemoprevention and anti-inflammatory characteristics of arenamides A and B warrant further investigation.

Resveratrol derivatives as promising chemopreventive agents with improved potency and selectivity

SCOPEnDespite scores of investigations, the actual impact of resveratrol (3,5,4-trihydroxy-trans-stilbene) on human health, as a dietary component or supplement, remains moot. This is due to many factors, such as relatively low potency, pleiotropic mechanisms, and rapid metabolism. Nonetheless, as a promiscuous molecule that interacts with numerous targets, resveratrol can be viewed as a scaffold for designing structural relatives potentially capable of mediating more intense responses with greater mechanistic stringency.nnnMETHODS AND RESULTSnWe currently report the synthesis and biological evaluation of 92 stilbene analogs. The compounds were tested with in vitro assays for activation of quinone reductase 1, inhibition of quinone reductase 2, nitric oxide production, aromatase, NFκB, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase, or cyclooxygenase-1 and -2, quenching of 2,2-diphenyl-1-picrylhydrazyl free radical, interaction with estrogen receptors, and as antiproliferative agents. Several compounds were found to mediate responses with much greater potency than resveratrol; some mediated pleiotropic responses, as is the case with the parent molecule, but others were highly specific or totally inactive. When administered to rats, higher serum concentrations and greater stability was demonstrated with prototype lead molecules.nnnCONCLUSIONnOwing to structural simplicity, facile syntheses are available for large-scale production. These data support the promise of more advanced development of novel resveratrol derivatives as drug entities.

Potential chemopreventive agents based on the structure of the lead compound 2-bromo-1-hydroxyphenazine, isolated from Streptomyces species, strain CNS284.

The isolation of 2-bromo-1-hydroxyphenazine from a marine Streptomyces species, strain CNS284, and its activity against NF-κB, suggested that a short and flexible route for the synthesis of this metabolite and a variety of phenazine analogues should be developed. Numerous phenazines were subsequently prepared and evaluated as inducers of quinone reductase 1 (QR1) and inhibitors of quinone reductase 2 (QR2), NF-κB, and inducible nitric oxide synthase (iNOS). Several of the active phenazine derivatives displayed IC₅₀ values vs QR1 induction and QR2 inhibition in the nanomolar range, suggesting that they may find utility as cancer chemopreventive agents.

Fijiolides A and B, Inhibitors of TNF-α-Induced NFκB Activation, from a Marine-Derived Sediment Bacterium of the Genus Nocardiopsis

Fijiolide A, a potent inhibitor of TNF-alpha-induced NFkappaB activation, along with fijiolide B, were isolated from a marine-derived bacterium of the genus Nocardiopsis. The planar structures of fijiolides A (1) and B (2) were elucidated by interpretation of 2D NMR spectroscopic data, while the absolute configurations of these compounds were defined by interpretation of circular dichroism and 2D NMR data combined with application of the advanced Moshers method. Fijiolides A and B are related to several recently isolated chloroaromatic compounds, which appear to be the Bergman cyclization products of enediyne precursors. Fijiolide A reduced TNF-alpha-induced NFkappaB activation by 70.3%, with an IC(50) value of 0.57 micro-M. Fijiolide B demonstrated less inhibition, only 46.5%, without dose dependence. The same pattern was also observed with quinone reductase (QR) activity: fijiolide A was found to induce quinone reductase-1 (QR1) with an induction ratio of 3.5 at a concentration of 20 microg/mL (28.4 microM). The concentration required to double the activity was 1.8 microM. Fijiolide B did not affect QR1 activity, indicating the importance of the nitrogen substitution pattern for biological activity. On the basis of these data, fijiolide A is viewed as a promising lead for more advanced anticancer testing.

Optimizing thiadiazole analogues of resveratrol versus three chemopreventive targets.

Chemoprevention is an approach to decrease cancer morbidity and mortality through inhibition of carcinogenesis and prevention of disease progression. Although the trans stilbene derivative resveratrol has chemopreventive properties, its action is compromised by weak non-specific effects on many biological targets. Replacement of the stilbene ethylenic bridge of resveratrol with a 1,2,4-thiadiazole heterocycle and modification of the substituents on the two aromatic rings afforded potential chemopreventive agents with enhanced potencies and selectivities when evaluated as inhibitors of aromatase and NF-κB and inducers of quinone reductase 1 (QR1).

Inhibition of lipopolysaccharide-induced cyclooxygenase-2 and inducible nitric oxide synthase expression by 4-[(2'-O-acetyl-α-L-rhamnosyloxy)benzyl]isothiocyanate from Moringa oleifera.

Moringa oleifera Lamarck is commonly consumed for nutritional or medicinal properties. We recently reported the isolation and structure elucidation of novel bioactive phenolic glycosides, including 4-[(2′-O-acetyl-α-L-rhamnosyloxy)benzyl]isothiocyanate (RBITC), which was found to suppress inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in lipopolysaccharide-stimulated RAW 264.7 mouse macrophage cells. Inhibitors of proteins such as cyclooxygenase-2 (COX-2) and iNOS are potential antiinflammatory and cancer chemopreventive agents. The inhibitory activity of RBITC on NO production (IC50 = 0.96 ± 0.23 μM) was greater than that mediated by other well-known isothiocyanates such as sulforaphane (IC50 = 2.86 ± 0.39 μM) and benzyl isothiocyanate (IC50 = 2.08 ± 0.28 μM). RBITC inhibited expression of COX-2 and iNOS at both the protein and mRNA levels. Major upstream signaling pathways involved mitogen-activated protein kinases and nuclear factor-κB (NF-κB). RBITC inhibited phosphorylation of extracellular signal-regulated kinase and stress-activated protein kinase, as well as ubiquitin-dependent degradation of inhibitor κBα (IκBα). In accordance with IκBα degradation, nuclear accumulation of NF-κB and subsequent binding to NF-κB cis-acting element was attenuated by treatment with RBITC. These data suggest RBITC should be included in the dietary armamentarium of isothiocyanates potentially capable of mediating antiinflammatory or cancer chemopreventive activity.