Grape seeds are a valuable source for obtaining enotannins, natural compounds with phenolic structures that possess remarkable antioxidant properties. In order to improve the physical-chemical properties of these compounds, by oxidation-reduction processes, their solubility’s were changed and were obtained new compounds with pronounced antioxidant, antibacterial and antifungal properties, which can be successfully used in important fields such as medicine, cosmetic and agriculture [1,2]. To broaden the spectrum of physical-chemical and pharmacological analysis of compounds in this class, Italian enotannins were selected as raw material for research, from white grape seeds (Tannin 1) and red grapes (Tannin 2), that were subjected to physical-chemical properties modification. New compounds, Tanoxil 1 and Tanoxil 2 were obtained by depolymerization reactions of macromolecular structures of initial enotannins Tannin 1 and respectively Tannin 2. [3] The total number of acidic functional groups (carboxylic and phenolic), Ctotal, by acid-base titration were determined, according to Temporary Pharmacopoeia Monograph for the pharmaceutically active substance Enoxil, adjusted to optimal parameters for measurements in aqueous 5% solutions. Ctotal values determined for Tanoxil products certify a double increase for Tanoxil 1 (Ctotal 0.1565 meq/g) or even triple increase for Tanoxil 2 (Ctotal 0.1901 meq/g) of the value of this parameter, compared to the total content of acidic functional groups of the initial tannin products Tannin 1 (Ctotal 0.0726meq/g) and respectively (Ctotal 0.0662 meq/g) for a 5% solution Tannin 2.The influence of storage time of 5% aqueous solutions of Tanoxil 1 and 2 on Ctotal parameter were studied. The obtained results allowed us to conclude that the total acidic functional groups (carboxylic and phenolic) remains practically unchanged during the studied period of 30 days. For the determination of antioxidant activities (AAT%) of the investigated compounds, it has been used ABTS radical cation decolorization assay. The obtained data indicate that the antioxidant activity of the new products, as it refers to Tanoxil 1 and 2, is very similar and, at the same time, is very high (93.16% -95.58%). These new compounds of natural origin have strong antioxidant activities and are of great interest for future microbiological and pharmacological research, as they have high antioxidant activities (about AAT% = 95) and a considerable content of acidic groups (Ctotal/g = 0,1901 meq/g).
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