Available online at www.sciencedirect.com Colloids and Surfaces A: Physicochem. Eng. Aspects 318 (2008) 134–140 Synthesis and properties of antioxidant amphiphilic ascorbate salts Thierry Koumbi Mounanga a,b , Philippe G´ erardin b , Boudah Poaty b , Dominique Perrin b , Christine G´ erardin a,∗ a ´ Equipe Mat´ eriaux Tensioactifs Polym` eres et Collo¨ ıdaux, LCPOC, UMR CNRS-UHP 7565, Nancy-Universit´ e, Facult´ e des Sciences et Techniques, BP 239, 54506 Vandoeuvre les Nancy, France b Equipe Chimie Organique et Microbiologie, LERMAB, UMR INRA-ENGREF-UHP1093, Nancy-Universit´ e, Facult´ e des Sciences et Techniques, BP 239, 54506 Vandoeuvre les Nancy, France Received 18 April 2007; received in revised form 12 December 2007; accepted 17 December 2007 Available online 6 January 2008 Abstract Synthesis of new surfactants with antioxidant properties was carried out from ascorbic acid and different fatty amines. Characterization of physicochemical properties of these new compounds indicated a classical behavior of cationic surfactants. Antioxidant properties, estimated using methyl linoleate oxidation inhibition and DPPH methods, were close to that of ascorbic acid tested in the same conditions. These compounds were investigated in the formulation of wood preservation mixtures containing propiconazole, a widely used fungicide, and compared to the formulation obtained with an industrial nonionic surfactant. Biological tests were carried out under laboratory conditions to evaluate the ability of these formulations to protect beech wood blocks exposed to Coriolus versicolor, a white rot fungus. Results indicated that using aqueous formulation of propiconazole allows reducing the quantity of biocide compared to solutions of the same concentrations in ethanol. Protection achieved with antioxidant surfactant was slightly superior to that obtained with conventional surfactant. © 2008 Elsevier B.V. All rights reserved. Keywords: Antioxidant; Aqueous formulation; Fungicide; Surfactant; Wood 1. Introduction Surfactants are widely used as detergents, cleaners, auxil- iaries for textiles, leather and paper, chemical treatments and processes, cosmetic, pharmaceutical and food industries [1]. Comprising a water-soluble part and a hydrophobic part, sur- factants are first used to reduce the surface tension of the liquid in which they are dissolved allowing the solubilization of compounds in this liquid. However, it could be of inter- est to synthesize surfactants with additional properties that could lead to specific applications. In that prospect, we have investigated the synthesis and characterization of amphiphilic compounds with antioxidant properties. Such compounds could find valuable applications in biological systems where radicals or active oxygen species like peroxides, hydroperoxides and hydroxyl radicals are involved or in processes where oxidations are involved in the degradation of different products like food ∗ Corresponding author. Tel.: +33 3 83 68 43 32; fax: +33 3 83 68 43 22. E-mail address: Christine.Gerardin@lesoc.uhp-nancy.fr (C. G´ erardin). or polymers. Due to the increasing trend to substitute chemicals from renewable origin for chemicals from petrochemical origin, we investigated the synthesis of surfactants derived from the reaction of ascorbic acid chosen as polar head with several fatty amines. Ascorbic acid (2,3-dehydro-l-gulonic acid -lactone, also known as vitamin C) is a powerful natural antioxidant. It has been reported to possess strong reductive properties due to the presence of the enediol moiety, leading to the use of some of its salts in medicinal preparations [2]. Ascorbic acid and its deriva- tives obtained by esterification of the primary hydroxyl group in position 6 with different carboxylic acids are strong radical scavengers with interesting applications as protective agents for fats, vitamins and other degradable materials [3–7]. Because of its structure, ascorbic acid is a water-soluble antioxidant, insol- uble in fats and unable to penetrate the lipophilic membranes of biological systems. The addition of a hydrocarbon chain such as an ester confers to the ascorbyl esters amphiphilic properties allowing their solubilization and penetration in biomembranes, where they can perform their antioxidant function. Wood is a naturally occurring polymer, consisting of cellu- lose, hemicelluloses and lignin, easily degraded by fungi, which 0927-7757/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfa.2007.12.048