ISSN 1420-3049 www.mdpi.com/journal/molecules Article
Derivatives of 10,16-Dihydroxyhexadecanoic Acid Isolated from Tomato (Solanum lycopersicum) as Potential Material for Aliphatic Polyesters
Daniel Arrieta-Baez *, Miguel Cruz-Carrillo, Mayra Beatriz Gómez-Patiño and L. Gerardo Zepeda-Vallejo Departamentode Química Orgánica, Escuela Nacional de Ciencias Biológicas-IPN, Prolongación de Carpio y Plan de Ayala S/N, Colonia Santo Tomás, D.F. 11340, Mexico * Author to whom correspondence should be addressed; E-Mail: firstname.lastname@example.org; Tel.: +52-55-5729-6300 Ext. 62345. Received: 6 May 2011; in revised form: 1 June 2011 / Accepted: 10 June 2011 / Published: 15 June 2011
Abstract: The mainmonomer of tomato cuticle, 10,16-dihydroxyhexadecanoic acid (or 10,16-dihydroxypalmitic acid; 10,16-DHPA), was isolated and used to efficiently synthesize two different monomers (16-hydroxy-10-oxo-hexadecanoic and 7-oxohexa-decanedioic acids) in addition to a dimer and linear and branched trimers. These compounds were fully characterized using NMR and MS techniques and could be used as startingmaterials for the synthesis of a wide range of chemicals and bio-polyesters, particularly the latter due to their physical properties, non-toxicity, and relative abundance among raw materials. Keywords: cutin; tomato; 16-hydroxyacids; dimer; trimer
1. Introduction There is a great need to develop chemistry that is based on the use of biodegradable and renewable resources . Natural aliphaticpolyesters are amongst the most important biocompatible and biodegradable materials that have received much recent attention; their applications in particular fields, such as agriculture, packaging, fiber, and biomedical research (e.g., tissue engineering, surgical suture, gene therapy, and controlled drug delivery) have grown significantly due to their availability as novel products with betterperformance characteristics [2,3]. Normally, polyester synthesis is performed by
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ester interchange reactions or by direct esterification of hydroxyacids or diacid/diol combinations from agro-resources, chemical synthesis and fossil resources (e.g., lactic acid-, fatty acid-derived materials, ε-caprolactones, different diols, adipic, sebacic or succinic acid, etc.)[4-8]. Development of these innovative biopolymer materials has been underway for a number of years, and continues to be an area of interest for many research fields [2,3,9]. Appreciable amounts of natural polyesters occur in higher plants as structural components; cutin, present in the cuticle that covers the aerial parts of plants, and suberin, which forms part of the periderm in woody plants, areboth examples of natural polyesters [10-12]. Their monomeric composition is usually complex and differs among plant species [10,11,13-17], and this complexity probably explains why the use of cutin and suberin as commercial sources of “green” chemicals has not been well-explored. Monomers such as ω-hydroxyl-hexadecanoic acid, α,ω-hexadecanedioic acid, and α,ω-hexadecanediol, which are present incutin and suberin, are found commercially and have been used in biological and polymeric studies [18-21]. On the other hand, aliphatic α,ω-dicarboxylic acids are used in the manufacture of engineered plastics, perfumes, lubricants, and adhesives . Tomato cutin is one of the most studied cuticles [11,15,22,23]. Various depolymerization protocols have indicated that the major monomers in thisunique natural polyester are 10,16-dihydroxyhexadecanoic acid (10,16-dihydroxypalmitic acid, 10,16-DHPA; more than 70%) and 16-hydroxyhexadecanoic acid [15,23,24]. However, studies describing the chemical or enzymatic reactions with purified monomers isolated from tomato cutin, have not yet been explored. These reactions require a robust chemical analysis in order to know the use of the monomers for...