Potential Edible Pectin-based film for high water soluble Ellagic Acid salt release

Diet and nutrition are fundamental factors in the promotion and maintenance of good health conditions. They occupy a prominent role in the prevention of chronic diseases like obesity, diabetes, cardiovascular diseases, cancer and osteoporosis [1]. Medical research has uncovered the causes of these chronic diseases: virtually, the underlying mechanisms of all of these diseases depend on oxidative processes, which lead to products that display high reactivity and are able to affect specific molecular targets in the body, like cellular DNA [2]. Pectin is an etero-polysaccharide composed by D-Xylose, D-apiose, D-galactose and galacturonic acid as the most abundant. In other terms, pectin could be identified as a multi-block copolymer where monosaccharide units (D-Xylose or D-Apiose) bond blocks of homogalacturonan together, i.e. nearby chains of α-(1–4)-linked D-galacturonic acid. Galacturonic acid is present as free acid moiety or as a methyl ester: the amount of ester units [degree of esterification (DE)] depends on the source of pectin and the method of extraction and affects the properties of pectin itself (i.e. water compatibility, ionic interaction among chains and bivalent cations). Pectins are commonly used for the production of drug release systems; in addition, the possibility to obtain a reversible gel adding bivalent cations, permits to tune the mechanical properties of gels tailoring them for specific aims. We report the preparation of pectin-based films used as potentially edible ellagic acid (EA) release devices. EA, a natural polyphenol mainly present in pomegranate, berries and grapes, was selected due to its antioxidant effects and apoptosis-inducing activity against certain types of cancer cells ; on the other hand, the poor water solubility of EA (≈10µg ml-1) dramatically reduces its bioavailability and its applications. We prepared a highly water soluble EA-lysine salt, used to produce pectin-based films, obtained via solvent casting deposition of a solution of pectin, CaCl2 and EA-lysine salt. Two different types of pectin were used: high and low methoxylated. The release properties were assessed according to calcium concentration, the DE and the amount of EA-lysine salt. Figure 1. Chemical structure of homogalacturonan and Ellagic acid References (1) Yeo, M.; Lee, H.; Kim, G. Biomacromolecules 2011, 12, 502-510. (2) Weisburger, J. Food and Chemical Toxicology 1999, 37, 943-948.