Amandine Léa Flourat

Macrobisphenols are a family of bio‐inspired bisphenols introduced in 2013, composed of two p ‐hydroxycinnamate units linked through ester bonds via a polyol scaffold. Unlike bisphenol A, macrobisphenols are non‐endocrine‐disrupting compounds, and display outstanding antiradical activity, making them attractive, safer alternatives for polymer‐related applications. Their versatility enables use as plasticizers, antioxidants, and monomers for polymer and materials synthesis. Over the past 12 years, substantial progress has been made to enhance their industrial viability by expanding structural diversity through extensive libraries of analogs, significantly lowering production costs, and minimizing environmental impact through greener synthetic strategies. This article critically reviews the evolution of macrobisphenol synthesis, highlights recent advances in sustainable and scalable pathways, and provides practical guidelines for selecting the most cost‐effective and environmentally responsible processes according to the targeted structure.

La nécessité d’un passage à une économie verte est de plus en plus pressante comme le confirme le récent rapport du GIEC. Afin de soutenir la structuration de filières agro-industrielles durables pour la production d’énergie ou de produits de commodité, le développement parallèle de marchés à plus petit volume mais avec une très forte valeur ajoutée est nécessaire. Parmi ces marchés à fort potentiel, les domaines de la santé et de la cosmétique sont particulièrement porteurs. Deux développements relevant de la chimie du végétal seront abordées par le prisme des coproduits générés à l’issue d’une première transformation de ressource renouvelable.En premier lieu, l’industrie papetière, en crise, génère de grandes quantités de sciure de bois qui peuvent être transformées par flash pyrolyse en lévoglucosénone. Cette molécule chirale, bi-cyclique (5 et 7 chaînons) présentant de nombreuses fonctionnalités chimiques (cétone, acétal, alcène) est un composé plateforme ouvrant un vaste champ d’opportunités pour la chimie biosourcée. L’obtention de molécules chirales à partir de la lévoglucosénone ouvre des applications dans le domaine pharmaceutique, dans le secteur du bio contrôle et aussi dans l’industrie agro-alimentaire.D’autre part, les acides para-hydroxycinnamiques obtenus à partir de résidus agricoles tels que le son de blé, les tourteaux de colza ou de tournesol ou encore le son de moutarde, représentent une source de composés phénoliques à fort potentiel. Ces molécules sont connues pour posséder un certain nombre d’activités physico-chimiques (anti-radicalaire, anti-UV) et biologiques (anticancéreux, anti-inflammatoire). Des voies de fonctionnalisation de ces molécules par des procédés de synthèse respectant les concepts de la chimie verte seront explorées dans le but d’améliorer ces propriétés, notamment pour la production d’anti-UV.

Stilbenes, such as resveratrol, possess numerous biological activities desirable in various industrial sectors ( e.g ., pharmaceutical, nutraceutical, and cosmetic). However, these activities are counteracted by their low bioavailability. In order to achieve an optimal hydrophylic/lipophilic balance (HLB) and thus maximize bioavailability, alkyl glucoside dimers of resveratrol ( i.e ., C2 to C12 alkyl oxystilbenin diglucosides (C8‐O4’ linkage) and δ‐Viniferin diglucoside (C3‐C8’ linkage)) were synthesized from piceid—a β‐glucoside of resveratrol—in one or two steps using a silver acetate‐mediated oxidative coupling in various alcoholic solvents as the key step. δ‐Viniferin diglucoside was functionalized by lauric acid using an enzyme‐mediated esterification. HLB values, determined from Log P (the partition coefficient between water and octan‐1‐ol), were calculated for the nine synthesized compounds, revealing that four exhibited values within the range considered favorable for bioabsorption. Finally, antiradical and antioxidant activities were assessed using DPPH and ORAC tests, respectively, prior to anti‐inflammatory testing on dermal human cells. These assays have shown very promising results with some activities overpassing that of resveratrol.

Derivatised aurones, based on phytochemical flavonoids, were synthesised and studied using steady‐state and ultrafast spectroscopy techniques. Aurones’ strong ultraviolet (UV) and visible absorption, in addition to being found in abundance in fruits, vegetables and flowers, makes them ideal photoprotection candidates for agrochemicals. Agrochemicals are well known to exhibit poor photostability, and the addition of photoprotectants to their formulations thus increases their longevity, and thereby environmental sustainability. The results presented here shed light on the complex ultrafast and long term photodynamics of five nature‐inspired derivatives in solution and on a wax surface, the latter designed to mimic the cuticle of a plant leaf. This study finds markedly different relaxation mechanisms between these condensed phase environments, highlighting the importance of studying photoprotectants in their real‐world environments. These findings inspire the development of safe and effective photoprotectants for agrochemicals.

Stilbenes are specialized metabolites that are particularly abundant in Vitis species. Although the biosynthetic pathways of stilbenes have been well-characterized, the role of specific peroxidases in stilbene oligomerization remains to be investigated. In this study, we used grapevine cell cultures to characterize the functional role of Vitis vinifera peroxidase 4 (VvPRX4) in the production of resveratrol oligomers after elicitation with methyl jasmonate (MeJA). We showed that MeJA triggers the accumulation of t-resveratrol, resveratrol dimers, and predicted resveratrol trimers in culture medium. This accumulation was correlated with upregulation of the PRX4 gene in grapevine cells. Using bacterial crude extracts containing VvPRX4, we demonstrated that VvPRX4 converts t-resveratrol into dimers, t-ε-viniferin into tetramers, and both combined substrates into resveratrol trimers. Additionally, VvPRX4 mediates the formation of glycosylated dimers using t-piceid and t-resveratrol as substrates. These results highlight the functional role of VvPRX4 in stilbene oligomerization in MeJA-elicited grapevine cell cultures.