Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.

Plant Polyphenols: Chemical Properties, Biological Activities, and Synthesis

Polyphenols as antimicrobial agents

Plant phenolics: recent advances on their biosynthesis, genetics, and ecophysiology.

Polyphenolic compounds present in tea, red wine, and chocolate form thin adherent polyphenol films on substrates through spontaneous adsorption from solution. From this observation emerged a versatile and comprehensive approach to surface modification of a variety of solid, porous, and nanoparticulate substrates composed of metals, ceramics, and polymers (see picture; ROS=reactive oxygen species).

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Colorless Multifunctional Coatings Inspired by Polyphenols Found in Tea, Chocolate, and Wine

Funf Portionen Obst und Gemuse am Tag! Das ist nach heutigen Masgaben notig, um fit und gesund zu bleiben, das wird uberall empfohlen und ebenso heftig beworben. Regelmasig gruner Tee, ab und zu Schokolade sowie der Genuss von ein paar Glaschen Rotwein am Tag sollen zusatzlich lebensverlangernd wirken. Warum? Eine vollstandige Antwort darauf kann die Wissenschaft noch nicht geben, aber eine bestimmte Klasse von naturlichen Substanzen, die in Obst und Gemuse vorkommt, gilt allgemein als besonders gesundheitsfordernd: die Polyphenole! Was aber sind diese pflanzlichen Stoffe genau? Welche physikalisch-chemischen Eigenschaften haben sie? Wie entfalten sie ihre biologische Wirkung? Konnen sie wirklich der Vorbeugung von Krankheiten dienen? Konnen aus ihnen neue Arzneimittel entwickelt werden? Wie weit ist die organische Synthese, um sie herzustellen? Dieser Aufsatz gibt einige Antwort aus der chemischen Perspektive, fasst den aktuellen Stand der Dinge zusammen und stellt die wichtigsten Fortschritte in der Polyphenolforschung vor.

Pflanzliche Polyphenole: chemische Eigenschaften, biologische Aktivität und Synthese

Synthetic helical aromatic amide foldamers and in particular those based on quinolines have recently attracted much interest due to their capacity to adopt bioinspired folded conformations that are highly stable and predictable. Additionally, the introduction of water-solubilizing side chains has allowed to evidence promising biological activities. It has also created the need for methods that may allow the parallel synthesis and screening of oligomers. Here, we describe the application of solid phase synthesis to speed up oligomer preparation and allow the introduction of various side chains. The synthesis of quinoline-based monomers bearing protected side chains is described along with conditions for activation, coupling, and deprotection on solid phase, followed by resin cleavage, side-chain deprotection, and HPLC purification. Oligomers having up to 8 units were thus synthesized. We found that solid phase synthesis is notably improved upon reducing resin loading and by applying microwave irradiation. We also demonstrate that the introduction of monomers bearing benzylic amines such as 6-aminomethyl-2-pyridinecarboxylic acid within the sequences of oligoquinolines make it possible to achieve couplings using a standard peptide coupling agent and constitute an interesting alternative to the use of acid chloride activation required by quinoline residues. The synthesis of a tetradecameric sequence was thus smoothly carried out. NMR solution structural studies show that these alternate aminomethyl-pyridine residues do not perturb the canonical helix folding of quinoline monomers in protic solvents, contrary to what was previously observed in nonprotic solvents.

Céline Douat-Casassus

Papers

Plant Polyphenols: Chemical Properties, Biological Activities, and Synthesis

Plant Polyphenols: Chemical Properties, Biological Activities, and Synthesis

Pflanzliche Polyphenole: chemische Eigenschaften, biologische Aktivität und Synthese

Solid phase synthesis of aromatic oligoamides: application to helical water-soluble foldamers.

Microwave-enhanced solid-phase synthesis of N,N'-linked aliphatic oligoureas and related hybrids.