Optimized ultrasonic-assisted deep eutectic solvents extraction of Clematis flammula L. leave s, phytochemical screening, biological activities and the characterization of its volatile compounds

Lately, green chemistry has pushed researchers to investigate alternative solvents for the recovery of phenolic compounds (PC). Therefore, the optimization of PC extraction from Clematis flammula L. leaves (CFL) using ultrasound-assisted deep eutectic solvents (UAE-DES) was investigated. Additionally, phytochemical screening, biological activity, and characterization of the bioactive molecules using gas chromatography coupled with mass spectrometry (GC–MS) were performed. Choline chloride-acetic acid (ChCl-Acet) was explored as a potential extractant of TPC (110 ± 5.98 mgGAE/Gdw) and the optimal extraction conditions were as follows: 18.2% of water, 49.4 °C, and 40 min of extraction time. Also, the in vitro antioxidant assays revealed that CFL extract was a potent antioxidant agent with a high inhibition compared to the control with 97.23 ± 1.72% and 94 ± 4.21% inhibition for ABTS and DPPH, respectively. CFL extract showed antimicrobial effects against fungus and two bacterial strains, namely Candida albicans (CA), Methicillin-resistant staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (PA), respectively, with a minimal inhibitor concentration (MIC) of 390 μg/mL. For the first time, GC–MS was used to assess the characterization and quantification of phenolic profiles. Protoanemonin (63.94%), phenol (8.76%), decamethyl (7.00%), linalool (5.47%), salicylic acid (4.66%), dodecamethyl (4.41%), and n -dexadecanoic acid (4.22%) were the major compounds identified. The obtained results highlight the effectiveness of choline chloride-based DES as an alternative extraction solvent for phenolic compounds for industrial and pharmaceutical applications.