CONICET | Buscador de Institutos y Recursos Humanos

Prosopis ruscifolia "vinal", a wild tree from Argentina, produces antioxidant compounds (AOC) in leavesunder oxidative stress. Theaim was to evaluate the factors affecting the extraction and stability (E&S) of the AOC from the leaves of vinal (VL). VL were obtained from trees grown on a saline in Santiago del Estero, dried at 40°C during 45 hs, milled, and stored at -20°C. Factors related to the E&S ofthe AOC tested using design experiments were: extraction method (infusion or decoction), pH (5, 7 or 9); ionic strength (I: 50 or 100 mM); temperature (T: 8 or 25°C) and the presence of light or darkness (D). For infusions, 1.6 g of VL was added to 10 mL of boiling buffer, whereas for decoction, the mixture of VL with buffer was boiled. The measurement of the antioxidant activity (AA) of the extracts was carried out by the method of capture of the radical ABTS. The factors that influence significantly (p=0.0536) the AOCextraction were: extraction method, resulting decoction more effective than infusion (up to 5% more of AA), and I, yielding greater AA when the I of the medium was 50 mM (up to 2% more). The pH did not influence the extraction of AOC (p = 0.4740). After 15 days of storage, it was observed that the highest pH (9), the highest T (25°C) and D were the best conditions for preserving the AOC, since 98.3% of initial AA is kept (up to 20% is lost in other conditions). Although the I of the buffer influenced the extraction did not affect the storage of AOC (p = 0.1682). It was observed that the extracts obtained by decoction are more stable from a microbiological point of view since the VL are boiled. To conclude, the best conditions to extract the AOC of the VL in a queous medium are: decoction, I=50 mM and the most appropriate conditions for storing of extract solutions during 15 days are a slightly alkaline medium, room T and D.

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