Valorization of Haloxylon scoparium aqueous extract by chromatographic separation on Sephadex LH-20 column

Many scientific researches, across various specialties, have been developed to investigate compounds isolated from medicinal plants and agri-food products. In this context, this study focuses on the valorization of Haloxylon scoparium , a plant native to southeast Morocco. The objective is to isolate and characterize fractions of plant extracts that exhibit significant antioxidant power using chromatographic separation methods. This work represents a continuation of previously conducted and published research on the same plant. Three separation series were performed on the aqueous extract (AE-HS _AP ) (IC50 = 0.65 mg/mL) using exclusion chromatography on a Sephadex LH-20 column, resulting in a total 19 of fractions. The antioxidant power of these fractions was assessed by the DPPH test. The results revealed some fractions exhibiting higher antioxidant activity compared to the initial extract. Notably, the fraction (F4'') registered an antioxidant activity (IC50 = 0.078 mg/mL) close to that of the reference compound ascorbic acid (IC50 = 0.08 mg/mL). Based on the phytochemical tests conducted in the previous study, alkaloids and polyphenols were identified in the aqueous extract. GC-MS analysis of fraction F4'' revealed a prominent presence of three alkaloid classes: tetrahydroisoquinolines (THIQ), phenylethylamines (PHEA), and tryptamines (TRPM). The most abundant compound detected was salsolinol, with a concentration of 252.09 mg per 100 g of dry matter. The high antioxidant activity observed in fraction F4'' may be largely attributed to salsolinol. Furthermore, this antioxidant capacity could also result from other polar compounds, such as polyphenols present in the fraction, or from a synergistic effect among these constituents.