Potential Natural Antioxidant and Anti-Inflammatory Properties of Carthamus caeruleus L. Root Aqueous Extract: An In Vitro Evaluation

Carthamus caeruleus L. is traditionally used in Algerian medicine, particularly for burn treatment, but its therapeutic potential remains insufficiently studied. This study aimed to evaluate the antioxidant and anti-inflammatory properties of the root aqueous extract, and to perform phytochemical characterization to identify its bioactive compounds. Phytochemical analysis was conducted using spectrophotometry and reverse-phase high-performance liquid chromatography (RP-HPLC). The antioxidant potential was assessed through various assays, including ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), DPPH radical scavenging, hydroxyl radical scavenging, ferrous ion chelation, and hydrogen peroxide decomposition. Anti-inflammatory activity was evaluated using membrane stabilization, protein denaturation, and membrane peroxidation assays. The extract exhibited moderate levels of polyphenols, flavonoids, and condensed tannins, quantified as 21.19 ± 0.37 mg GAE/g, 0.72 ± 0.013 mg QE/g, and 27.28 ± 1.04 mg TAE/g of dry extract, respectively. RP-HPLC analysis identified 22 phytochemical compounds, primarily phenolic acids, flavonoids, and tannins, with orientin and vanillin as the major constituents. The extract demonstrated significant antioxidant activity, with moderate efficacy in TAC and FRAP assays (IC50 values of 5405.1 ± 4.42 and 1132.35 ± 4.97 µg/mL, respectively). Notable activities included DPPH and hydroxyl radical scavenging (34.43 ± 4.83 and 512.81 ± 9.46 µg/mL, respectively), ferrous ion chelation (2462.76 ± 1.38 µg/mL), lipid peroxidation inhibition (22.32 ± 3.31%), and hydrogen peroxide decomposition (263.93 ± 7.87 µg/mL). Additionally, the extract stabilized erythrocyte membranes under osmotic, thermal, and oxidative stress conditions (98.13 ± 0.15%, 70 ± 1.27%, and 89 ± 0.87%, respectively), inhibited ovalbumin denaturation (81.05 ± 2.2%), and protected against lipid peroxidation in brain homogenates (69.25 ± 0.89%). These findings support the traditional therapeutic applications of C. caeruleus and highlight its potential as a source of antioxidant and anti-inflammatory agents.