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Dinuclear Re(I) complexes have proportionally been much less studied than mononuclear analogues. In particular, very little information is available about their solid-state emission properties. In this work, two structural isomers of dinuclear complexes (Bi-Re-metaPhe and Bi-Re-paraPhe), which differ by the relative position of the coordination spheres on a central phenyl ring, were synthesized and compared with each other and with the parent mononuclear compound (Mono-Re-Phe), from a theoretical and experimental point of view. In solution, the electronic, electrochemical and spectroscopic properties of the dinuclear complexes were almost identical, and rather close to those of the monomer. In the solid state, the photoluminescence (PL) efficiency of dimers was not higher than that of the monomer, but a clear mechanoresponsive luminescence (MRL) effect appeared only for the former ones. The positional isomerism influenced the amplitude of this effect, as well as the aggregation-induced emission (AIE) properties in a water-acetonitrile mixture. This study reveals the importance of positional isomerism to modulate the emission properties in the solid state. It also shows the advantage of dinuclear structures to access new MRL-active materials.

The tricarbonylrhenium complexes that incorporate a mesoionic carbene ligand represent an emerging and promising class of molecules, the solid-state optical properties of which have rarely been investigated. The aim of this comprehensive study is to compare three of these complexes with their 1,2,3-triazole-based analogues. The Hirshfeld surface analysis of the crystallographic data revealed that the triazolylidene derivatives are more prone to π-π interactions than their 1,2,3-triazole-based counterparts. The FT-IR and electrochemical data indicated a stronger electron donor effect from the organic ligand to the rhenium atom for triazolylidene derivatives, which was confirmed by DFT calculations. All compounds were phosphorescent in solution, where the 1,2,3-triazole-based complexes showed unusually strong dependence on dissolved oxygen. All compounds also emitted in the solid state, some of them exhibited marked solid-state luminescence enhancement (SLE) effect. The 1,2,3-triazole based complex Re-Phe even displayed astounding photoluminescence efficiency with quantum yield up to 0.69, and proved to be an excellent candidate for applications linked to aggregation-induced emission (AIE). Interestingly, one triazolylidene-based complex (Re-T-BOP) showed attractive antibacterial activity. This study highlights the potential of these new molecules for applications in the fields of photoluminescent and therapeutic materials, and provides the first bases for the design of efficient molecules in these research areas.

Since intramolecular π-π stacking interactions can modify the geometry, crystal packing mode, or even the electronic properties of transition metal complexes, they are also likely to influence the solid-state luminescence properties. Following this concept, a new tricarbonylrhenium(I) complex (Re-BPTA) was designed, based on a simple symmetrical 5,5'-dimethyl-4,4'-diphenyl-3,3'-bi-(1,2,4-triazole) organic ligand. The complex was prepared in good yield using a three-step procedure. The crystallographic study revealed that both phenyl rings are located on the same side of the molecule, and twisted by 71° and 62°, respectively, with respect to the bi-(1,2,4-triazole) unit. They overlap significantly, although they are slipped parallel to each other to minimize the intramolecular interaction energy. The π-π stacking interaction was also revealed by 1 H NMR spectroscopy, in good agreement with the results of theoretical calculations. In organic solutions, a peculiar electrochemical signature was observed compared to closely-related pyridyl-triazole (pyta)-based complexes. With regard to the optical properties, the stiffness of the Re-BPTA complex led to the stabilization of the 3 MLCT state, and thus to an enhancement of the red phosphorescence emission compared to the more flexible pyta complexes. However, an increased sensitivity to quenching by oxygen appeared. In the microcrystalline phase, the Re-BPTA complex showed strong photoluminescence (PL) emission in the green-yellow wavelength range ( λ PL = 548 nm, Φ PL = 0.52, 〈 τ PL 〉 = 713 ns), and thus a dramatic solid-state luminescence enhancement (SLE) effect. These attractive emission properties can be attributed to the fact that the molecule undergoes little distortion between the ground state and the triplet excited state, as well as to a favorable intermolecular arrangement that minimizes detrimental interactions in the crystal lattice. The aggregation-induced phosphorescence emission (AIPE) effect was clear, with a 7-fold increase in emission intensity at 546 nm, although the aggregates formed in aqueous medium were much less emissive than the native microcrystalline powder. In this work, the rigidity of the Re-BPTA complex is reinforced by the intramolecular π-π stacking interaction of the phenyl rings. This original concept provides a rhenium tricarbonyl compound with very good SLE properties, and could be used more widely to successfully develop this area of research.

Tricarbonylrhenium(I) complexes that incorporate a chloride ligand are promising photoluminescent materials, but those incorporating a bromide or iodide ligand have received very little attention regarding their solid-state properties. In this work, three rhenium(I) complexes differing only by the nature of their halide ligand (X = Cl, Br, and I) were compared. They are based on a fac-[ReX(CO) 3 (N^N)] framework where the N^N bidentate ligand is a 3-(2-pyridyl)-1,2,4-triazole unit functionalized by an appended phenyl group. DFT calculations showed that the character of the lowest energy transitions progressively changes from Re → N^N ligand (MLCT) to X → N^N ligand (XLCT) when increasing the size of the halogen atom. Regarding the electrochemical behavior, the chloride and bromide complexes 1-Cl and 1-Br were similar, while the iodide complex 1-I exhibited a strikingly different electrochemical signature in oxidation. From a spectroscopic viewpoint, all three complexes emitted weak red-orange phosphorescence in dichloromethane solution. However, in the solid state, marked differences appeared. Not only was 1-Cl a good emitter of yellow light, but it had strong solid-state luminescence enhancement (SLE) properties. In comparison, 1-Br and 1-I were less emissive and they showed better mechanoresponsive luminescence (MRL) properties, probably related to a loose molecular arrangement in the crystal packing and to the opening of vibrational non-radiative deactivation pathways. This study highlights for the first time how the nature of the halide ligand in this type of complex allows fine tuning of the solid-state optical properties, for potential applications either in bio-imaging or in the field of MRL-active materials., (© 2022. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)

Inflammation mediators enhance the activity of connexin (Cx) hemichannels, especially in the epithelial and endothelial tissues. As potential release routes for injury signals, such as (oligo)nucleotides, Cx hemichannels may contribute to long-lasting inflammation. Specific inhibition of Cx hemichannels may therefore be a mode of prevention and treatment of long-lasting, chronic sterile inflammation. The activity of Cx hemichannels was analysed in N2A and HeLa cells transfected with human Cx26 and Cx46 as well as in Calu-3 cells, using dye uptake as functional assay. Moreover, the possible impacts of the bioactive phenolic agents CVB2-61 and CVB4-57 on the barrier function of epithelial cells was analysed using Calu-3 cells. Both agents inhibited the dye uptake in N2A cells expressing Cx26 (>5 µM) and Cx46 (>20 µM). In Calu-3 cells, CVB2-61 and CVB4-57 reversibly inhibited the dye uptake at concentrations as low as 5 µM, without affecting the gap junction communication and barrier function, even at concentrations of 20 µM. While CVB2-61 or CVB4-57 maintained a reduced dye uptake in Calu-3 cells, an enhancement of the dye uptake in response to the stimulation of adenosine signalling was still observed after removal of the agents. The report shows that CVB2-61 and CVB4-57 reversibly block Cx hemichannels. Deciphering the mechanisms of the interactions of these agents with Cx hemichannels could allow further development of phenolic compounds to target Cx hemichannels for better and safer treatment of pathologies that involve Cx hemichannels.

Strongly luminescent tricarbonylrhenium(I) complexes are promising candidates in the field of optical materials. In this study, three new complexes bearing a 3-(2-pyridyl)-1,2,4-triazole (pyta) bidentate ligand with an appended phenyl group were obtained in very good yields owing to an optimized synthetic procedure. The first member of this series, i.e. complex 1, was compared with the previously studied complex RePBO to understand the influence of the fluorescent benzoxazole unit grafted on the phenyl ring. Then, to gauge the effect of steric hindrance on the luminescence properties, the phenyl group of complex 1 was substituted in the para position by a bulky tert -butyl group or an adamantyl moiety, affording complexes 2 and 3, respectively. The results of theoretical calculations indicated that these complexes were quite similar from an electronic point of view, as evidenced by the electrochemical study. In dichloromethane solution, under excitation in the UV range, all the complexes emitted weak phosphorescence in the red region. In the solid state, they could be excited in the blue region of the visible spectrum and they emitted strong yellow light. The photoluminescence quantum yield was markedly increased with raising the size of the substituent, passing from 0.42 for 1 to 0.59 for 3. The latter complex also exhibited clear waveguiding properties, unprecedented for rhenium complexes. From this point of view, these easy-synthesized and spectroscopically attractive complexes constitute a new generation of emitters for use in imaging applications and functional materials. However, the comparison with RePBO showed that the presence of the benzoxazole group leads to unsurpassed mechanoresponsive luminescence (MRL) properties, due to the involvement of a unique photophysical mechanism that takes place only in this type of complex.

Inflammation involving the innate and adaptive immune systems is a normal response to infection. However, if it becomes uncontrolled, inflammation may result in autoimmune or auto inflammatory disorders, neurodegenerative diseases or cancers. The currently available anti-inflammatory drug therapy is often not successful or induces severe side effects. Thus, the search of new therapeutic options for the treatment of inflammation is highly required. Medicinal plants have been an interesting source for obtaining new active compounds. Diarylheptanoids characterized by a 1, 7-diphenylheptane structural skeleton, are a class of secondary plant metabolites that have gained increasing interest over the last few decades due to a wide variety of biological activities. This review covers 182 natural linear or macrocyclic diarylheptanoids described in the period of 1982 to 2020 with anti-inflammatory activities evaluated using quantified in vitro and/or in vivo assays. All of these data highlight the pharmacological potential of these natural compounds to act as anti-inflammatory drugs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Reactive oxygen species (ROS) are key signaling molecules and their overproduction plays an important role in the inflammation process, the secretion of inflammatory cytokines such as IL-1β and IL-6 and the progression of inflammatory disorders. Decreasing oxidative stress represents a promising challenge in the design of antioxidant and anti-inflammatory agents. In the present study, a series of new diarylheptanoids containing allylic alcohol, amide, hydantoin or triazole fragments were synthesized and fully characterized. We evaluated the ability of these agents to block the production of intracellular ROS and the subsequent inflammatory events exerted by lipopolysaccharide (LPS) on murine macrophage RAW 264.7. Five diarylheptanoids were found to exhibit the dual required properties., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Tedarene A is a macrocyclic diaryl ether heptanoid isolated from the marine sponge Tedania ignis showing an inhibitory effect against nitric oxide production. The first total synthesis of tedarene A was achieved starting from the commercially available 3-(4-methoxyphenyl)propan-1-ol in nine steps and 15.3% overall yield. The synthetic sequence featured an E,Z-dienic bond introduction and a macrocyclization under Ullman conditions. During the synthesis, the E,E-isomer of tedarene A was also obtained and fully characterized.

The neovascularization of atherosclerotic lesions is involved in plaque development and may contribute to intraplaque hemorrhage and plaque fragilization and rupture. Among the various proangiogenic agents involved in the neovascularization process, proatherogenic oxidized LDLs (oxLDLs) contribute to the formation of tubes via the generation of sphingosine 1-phosphate (S1P), a major mitogenic and proangiogenic sphingolipid mediator. In this study, we investigated whether 4-hydroxynonenal (4-HNE), an aldehydic lipid oxidation product abundantly present in oxLDLs, contributes to their proangiogenic properties. Immunofluorescence analysis of human atherosclerotic lesions from carotid endarterectomy showed the colocalization of HNE-adducts with CD31, a marker of endothelial cells, suggesting a close relationship between 4-HNE and neovessel formation. In vitro, low 4-HNE concentration (0.5-1  µ M) elicited the formation of tubes by human microvascular endothelial cells (HMEC-1), whereas higher concentrations were not angiogenic. The formation of tubes by 4-HNE involved the generation of reactive oxygen species and the activation of the sphingolipid pathway, namely, the neutral type 2 sphingomyelinase and sphingosine kinase-1 (nSMase2/SK-1) pathway, indicating a role for S1P in the angiogenic signaling of 4-HNE. Carbonyl scavengers hydralazine and bisvanillyl-hydralazone inhibited the nSMase2/SK1 pathway activation and the formation of tubes on Matrigel® evoked by 4-HNE. Altogether, these results emphasize the role of 4-HNE in the angiogenic effect of oxLDLs and point out the potential interest of pharmacological carbonyl scavengers to prevent the neovascularization process.

A series of bis-hydrazones derived from diaryl and diaryl ether hydroxybenzaldehyde frames 1 and 2 have been synthesized as potential antioxidant and antiangiogenic agents, two properties required to limit atherogenesis and cardiovascular events. These compounds were evaluated for their ability to neutralize free radical formation, to block endothelial cell-induced low-density lipoprotein oxidation (monitored by the formation of TBARS), an essential step in atherogenesis, and subsequent toxicity, to prevent angiogenesis evoked by low oxidized LDL concentration (monitored by the formation of capillary tubes on Matrigel) and to inhibit intracellular ROS increase involved in the angiogenic signaling. A structure/activity study has been carried out and finally allowed to select the phenolic diaryl ether hydralazine derivative 2a, sharing all these protective properties, as a promising hit for further development., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

PAI-1, a glycoprotein from the serpin family and the main inhibitor of tPA and uPA, plays an essential role in the regulation of intra and extravascular fibrinolysis by inhibiting the formation of plasmin from plasminogen. PAI-1 is also involved in pathological processes such as thromboembolic diseases, atherosclerosis, fibrosis and cancer. The inhibition of PAI-1 activity by small organic molecules has been observed in vitro and with some in vivo models. Based on these findings, PAI-1 appears as a potential therapeutic target for several pathological conditions. Over the past decades, many efforts have therefore been devoted to developing PAI-1 inhibitors. This article provides an overview of the publishing activity on small organic molecules used as PAI-1 inhibitors. The chemical synthesis of the most potent inhibitors as well as their biological and biochemical evaluations is also presented., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

A novel series of hydrazones derived from substituted benzaldehydes have been synthesized as potential antiatherogenic agents. Several methods were used for exploring their antioxidant and cytoprotective properties, such as their scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, the inhibition of superoxide anion (O₂(·-)) generation and the measurement of cell-induced low-density lipoprotein oxidation (monitored by the formation of TBARS). The cytoprotective efficacy was also evaluated by measuring the cell viability (monitored by the MTT assay) in the presence of cytotoxic oxidized LDL. In this report, we discuss the relationship between the chemical structure of phenolic hydrazones and their antioxidant and cytoprotective activities, for subsequent application as antiatherogenic agents. This SAR study confirms that the phenolic frame is not the only prerequisite for antioxidant activity and N-methylbenzothiazole hydrazone moiety magnifies the dual required properties in two most interesting derivatives., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: The high susceptibility of human immunodeficiency virus-infected people to tuberculosis (TB), the emergence of multi-drug-resistant (MDR-TB) strains and extensively drug-resistant (XDR-TB) ones, has brought TB into the focus of urgent scientific interest. As a result, there has been an upsurge in recent years to find new anti-TB agents, with the cinnamoyl moiety having been identified as a particularly simple and effective pharmacophore for this purpose., Areas Covered: This review aims at highlighting the potential of (non)natural cinnamic derivatives to treat TB. It provides an overview of the worldwide recent patent and literature surrounding this type of easy-to-prepare small molecules. There is a special focus on their salient structural and chemical features involved in the reported anti-TB activities., Expert Opinion: Cinnamic derivatives clearly appear as attractive drug candidates to combat TB. So far, literature has reported that they are easy to synthesize and have promising anti-TB activities. Nevertheless, the mode(s) of action of these small molecules remain(s) to date obscure, which is why the implicated molecular mechanisms deserve to be investigated in further detail in the near future.

Reactive oxygen species (ROS) generated within the vascular wall trigger low-density lipoprotein (LDL) oxidation, lipid peroxidation, and carbonyl stress that are involved in atherogenesis. We recently reported that the antihypertensive drug, hydralazine, exhibits carbonyl scavenger and antiatherogenic properties, but only moderate antioxidant activity, so that high concentrations are required for inhibiting LDL oxidation. We aimed to develop agents sharing both antioxidant and carbonyl scavenger properties. We have synthesized a new hydralazine derivative, the bisvanillyl-hydralazone (BVH). BVH strongly inhibited LDL oxidation induced by copper and by human endothelial cells (HMEC-1), and prevented the formation of macrophagic foam cells. BVH reduced both the extracellular generation of ROS (superoxide anion and hydrogen peroxide) induced by oxidized LDL (oxLDL), as well as intracellular oxidative stress and proteasome activation, NFkappaB activation, and oxLDL-mediated proinflammatory signaling. In parallel, BVH prevented the carbonyl stress induced by oxLDL on cellular proteins, and blocked the apoptotic cascade as assessed by the inhibition of Bid cleavage, cytochrome C release, and DEVDase activation. Lastly, BVH prevented atherogenesis and carbonyl stress in apoE(-/-) mice. In conclusion, BVH is the prototype of a new class of antioxidant and carbonyl scavenger agents designed for new therapeutical approaches in atherosclerosis.

Tuberculosis, HIV coinfection with TB, emergence of multidrug-resistant TB, and extensively drug-resistant TB are the major causes of death from infectious diseases worldwide. Because no new drug has been introduced in the last several decades, new classes of molecules as anti-TB drugs are urgently needed. Herein, we report the synthesis and structure-activity relationships of a series of thioester, amide, hydrazide, and triazolophthalazine derivatives of 4-alkoxy cinnamic acid. Many compounds exhibited submicromolar minimum inhibitory concentrations against Mycobacterium tuberculosis strain (H(37)Rv). Interestingly, compound 13e, a 4-isopentenyloxycinnamyl triazolophthalazine derivative, was found to be 100-1800 times more active than isoniazid (INH) when tested for its ability to inhibit the growth of INH-resistant M. tuberculosis strains. The results also revealed that 13e does not interfere with mycolic acid biosynthesis, thereby pointing to a different mode of action and representing an attractive lead compound for the development of new anti-TB agents.

Cinnamic acid and its phenolic analogues are natural substances. Chemically, in cinnamic acids the 3-phenyl acrylic acid functionality offers three main reactive sites; substitution at the phenyl ring, addition at the α,β- unsaturation and the reactions of the carboxylic acid functionality. Owing to these chemical aspects cinnamic acid derivatives received much attention in medicinal research as traditional as well as recent synthetic antitumor agents. We observed that in spite of their rich medicinal tradition, cinnamic acid derivatives and their anticancer potentials remained underutilized for several decades since the first published clinical use in 1905. In last two decades, there has been huge attention towards various cinnamoyl derivatives and their antitumor efficacy. This review provides a comprehensive and unprecedented literature compilation concerning the synthesis and biological evaluation of various cinnamoyl acids, esters, amides, hydrazides and related derivatives in anticancer research. We envisage that our effort in this review contributes a much needed and timely addition to the literature of medicinal research.

A novel series of hydrazones derived from syringaldehyde and their antioxidant properties have been explored. Several employed methods such as scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(+)) radical cation expressed as Trolox equivalent antioxidant capacity (TEAC), inhibition of superoxide anion (O(2)(-)) generation and of human cell-mediated low-density lipoprotein oxidation (monitored by the formation of TBARS) exhibited their potent antioxidant properties. The carbonyl scavenger efficacy was also evaluated by measuring the ability to decrease the protein carbonyl content in cells challenged with oxidized LDL. In this report, we discuss about the synthesis of hydrazones and their dual biological role, antioxidant and carbonyl scavenger for further application in atherosclerosis., (Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.)

A series of new 2(4-alkoxyphenyl)cyclopropyl hydrazide- and triazolo-derivatives were synthesized starting from 4-hydroxycinnamic acid (1) in a clean, mild, efficient and straightforward synthetic protocol. These compounds consisting of different alkoxy substitution, phenylcyclopropyl backbone and different heterocyclic groups were evaluated for in vitro anticancer activity against 4 cell lines displaying certain levels of resistance to pro-apoptotic stimuli and 2 cell lines sensitive to pro-apoptotic compounds. Compounds 7f and 8e were most active and displaying moderate in vitro cytostatic effect through different mechanisms. Significantly, chemically modified derivatives could be obtained in order to develop novel types of compounds aiming to combat apoptosis-resistant cancers, for example, those cancers associated with dismal prognoses., (Copyright 2010 Elsevier Ltd. All rights reserved.)

In an effort to develop potent new antituberculous drugs effective against Mycobacterium tuberculosis, we have prepared series of cinnamic derivatives (thioesters and amides) with 4-hydroxy and 4-alkoxy groups and investigated the in vitro activities of these compounds. Among them some displayed a good in vitro antibacterial activity, such as (E)-N-(2-acetamidoethyl)-3-{4-[(E)-3,7-dimethylocta-2,6-dienyloxy]phenyl}acrylamide 4b that showed a minimum inhibitory concentration of 0.1microg/mL (0.26microM) against M. tuberculosis H37Rv.

On the basis of the 5,5'-bisvanillin scaffold, a series of compounds has been synthesized presenting symmetric or dissymmetric frames on each phenolic moiety. These frames are alpha,beta-unsaturated (fluoro)phosphonate and/or alpha,beta-unsaturated hydrazone(s) formed by coupling aldehydic with isoniazid or hydralazine. All compounds were tested for their ability to inhibit cell-mediated low-density lipoprotein oxidation. Oxidized low-density lipoprotein induced cytotoxicity was also evaluated along with the carbonyl scavenger properties of selected compounds. The most efficient agents were found to be those possessing at least one hydralazinone frame, with the most potent being the symmetrical compound: 4,4'-dihydroxy-3,3'-dimethoxy-5,5'-biphenyl-1,1'-(diphthalazin-1-yl)methylhydrazone hydrochloride.

Oxidative dimerization of ferulic acid methyl ester afforded dihydrobenzofuran derivative and new linear compound identified by X-ray crystallography. The gallate derivatized dihydrobenzofuran analogue was obtained and all compounds were evaluated for potential antiatherogenic, antiplasmodial (best IC(50)=0.8 microM) and cytotoxic activities.

A series of cinnamic and phosphonocinnamic derivatives have been synthesized and their ability to inhibit cell-mediated LDL oxidation and oxidized LDL-induced cytotoxicity was investigated. Electron-donating substituents surrounding the necessary 4-OH group of the aromatic ring showed the best results. Among the different series tested, amide 1, thioester 5c, phosphonoester 7c, and the fluorophosphonocinnamic analogue 12c exhibited a potent inhibitory effect against LDL oxidation (and subsequent toxicity) mediated by cultured human microvascular endothelial cells (HMEC-1), with an efficacy comparable to that observed with probucol. Beside this indirect protective effect, these compounds exhibited a direct protective effect against the toxicity of previously oxidized LDL in HMEC-1. These data suggest that the newly synthesized cinnamic compounds should protect against early events (cell-mediated LDL oxidation) occurring within the vascular wall in atherosclerosis.

Cinnamoyl coenzyme A reductase (CCR, EC 1.2.1.44), one of the key enzymes in the biosynthesis of lignin monomers, catalyzes the NADPH-dependent reduction of cinnamoyl-CoA esters to their corresponding cinnamaldehydes. AtCCR1, one of the two distinct isoforms isolated from Arabidopsis thaliana, was shown to be involved in lignin biosynthesis during development. Here, we report on the purification of the recombinant AtCCR1 protein expressed in Escherichia coli and the subsequent determination of its kinetic properties (K(m) and k(cat)/K(m) values) towards its main substrates i.e. feruloyl-CoA, sinapoyl-CoA, and p-coumaroyl-CoA esters. In addition, the potential inhibitory effect of five substrate-like analogs possessing an N-acetylcysteamine thioester group was tested on CCR activity using either feruloyl-CoA or sinapoyl-CoA as substrates. The K(i) values were in the range of 4.4-502 microM and the type of inhibition was found to be either uncompetitive or noncompetitive. Interestingly, for compounds 3 and 5, the type of inhibition was found to be different depending on the substrate used to monitor the enzyme activity. The best inhibitors were those possessing the feruloyl (compound 3) and sinapoyl (compound 5) aromatic moiety (4.1 and 7.1 microM) while the enzyme activity was monitored using the corresponding substrates.

Coniferyl alcohol was polymerized in pectin solution in order to mimic the lignification that is the final step of biosynthesis of plant cell wall. Dehydrogenated polymers (DHP = coniferyl alcohol polymers = synthetic lignin) interact with pectin to form hydrophobic clusters as monitored by pyrene fluorescence spectroscopy. The structure of these clusters was studied during the polymerization of synthetic lignin by static and quasielastic light scattering and small angle neutron scattering experiments. We show that synthetic lignin and pectin contribute to the same clusters, but the inner structure of these clusters is very heterogeneous and displays three phases. One observes a segregation between well separated pectin and lignin rich phases at length scales below approximately 30 nm. As a corollary of this segregation, clusters embody a large amount of solvent. On average, the density of the polymer rich phase (lignin plus pectin) inside clusters increases while its specific surface area decreases throughout the polymerization process. These results are discussed with respect to in vivo lignification of the plant cell wall.

The case of a young boy developing hypertension 3 years after removal of a small kidney due to pyelonephritis and vesico-ureteral reflux. Discovery in the artery of the remaining kidney of a limited coarctation without any of the lesions usually responsible for hypertension. Cured by enlargement angioplasty with a 5 year follow-up. This case is interpreted as an example (to our knowledge the only case in the literature) of hypertension, the mechanism of which is that revealed by Schlegel's experiments.