Valorisation des polyphénols des feuilles de Carthamus caeruleus L. : Étude phytochimique et évaluation in vitro des activités antioxydante, anti-inflammatoire et anticoagulante

Abstract

Carthamus caeruleus L. (Asteraceae) is a well-known medicinal plant widely used in Algerian traditional medicine, specifically for the treatment of skin burns and wounds. While previous studies have mainly focused on its roots, this work aims to evaluate the phytochemical profile and biological potential of polyphenolic extract of its leaves. The plant material (leaves) was harvested at an early growth stage in the Djemila region (Sétif, Algeria), dried, powdered, and subjected to ultrasound-assisted extraction (UAE) using a 70% hydro-ethanolic solvent after a defatting process. This extraction method yielded a significant recovery rate of 26.3%. Quantitative spectrophotometric estimations carried out to determine total polyphenol and flavonoid contents using the Folin-Ciocalteu and aluminum chloride methods, respectively revealed high amounts of phenolic compounds. The total phenolic content (TPC) reached 88.54 ± 0.75 mg GAE/g extract, and the total flavonoid content (TFC) was 55.20 ± 0.35 mg QE/g extract. The biological activities were thoroughly assessed. The antioxidant capacity, investigated via DPPH and Total Antioxidant Capacity (TAC) assays, demonstrated potent free radical scavenging properties with an IC50 of 370 ± 0.02 µg/mL and an A0.5 value of 280 µg/mL, respectively. Furthermore, the in vitro anti-inflammatory evaluation using the bovine serum albumin (BSA) denaturation assay showed remarkable, dose-dependent protection, reaching a maximum inhibition of 90.91 ± 0.90% at 0.5 mg/mL, which is significantly higher than the commercial drug aspirin (80.69%). Anticoagulant screening, evaluated through Prothrombin Time (PT) and Kaolin Cephalin Time (TCK) tests, indicated a clear concentration-dependent prolongation of clotting times, confirming a direct impact on the coagulation cascade. In conclusion, these findings scientifically justify the traditional therapeutic value of Carthamus caeruleus leaves as a rich source of safe, natural bioactive agents with potent antioxidant, anti-inflammatory, and anticoagulant properties, opening promising perspectives for future pharmaceutical and therapeutic applications. Keywords :Carthamus caeruleus, polyphenols, flavonoids, antioxidant activity, anti-inflammatory activity, anticoagulant activity.