Phenolic compounds and biological activities of different organs from aerial part of Nitraria retusa (Forssk.) Asch.: effects of solvents

Nitraria retusa is an edible halophyte shrub that is known for its high importance in folk medicine and ecology. . The fruits are tasty, eaten by humans and birds and are used to prepare a refreshing juice. The fleshy and bitter leaves of N. retusa, mixed with water, were used to make poultices, which are applied to reduce swellings. The dry leaves are used, in decoction, as a substitute for tea. Many phytochemical studies on this plant showed its diversity in active compounds such as phenolic compounds. In this work, the biochemical analysis and biological effects were investigated for water-ethanol/methanol/acetone extracted from leaves, flowers, stems, and fruits using two different extraction methods. Results revealed that polyphenol amounts were highest in leaves extracted by hydroethanolic decoction method with 46.97 mg GAE/g DW. Ethanol 70% leaves extracts has the highest contents of condensed tannins with 26.06 mg Cat/g DW by decoction, followed by methanol 70% water. Furthermore, four flavonoids were identified by HPLC-DAD: Luteolin 7-O-glucoside, Rutin, Kaempferol 3-O-rutinoside, and Isorhamnetin 3-O-rutinoside. For antioxidant activity, ethanol fraction was renowned for a high total antioxidant activity with 45.82 mg GAE/g DW and an important antiradical activity with an IC 50 of 22.05 µg/mL. The ethanolic extract showed the best activity inhibiting the production of NO* at an IC 50 of 36.60 µg/mL. These results show that this plant could be a promising source of bioactive substances and can be used for the production of juices and functional food supplements.