Interaction of Clematis flammula extracts with membrane models: characterization of anti-inflammatory and antibacterial activities

The present study aimed at elucidating the anti-inflammatory, antioxidant, and antibacterial mechanisms of Clematis flammula (CF) leaf extracts. Methodologically, antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl and ferric ion reducing antioxidant power assays, and antibacterial activity was assessed using Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) cell cultures. Anti-inflammatory potency was evaluated through cyclooxygenase and trypsin inhibitory activities. Moreover, the anti-inflammatory and antibacterial mechanisms of the active extracts were elucidated using two membrane models: erythrocytes and liposomes. The phenolic compounds in the extracts were identified using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Ethyl acetate extract inhibited S. aureus growth at a minimum inhibitory concentration of 78 μg/mL, possibly due to its lytic activity of liposomes (56.75 ± 0.54%). Additionally, the extract presented the best anti-trypsin activity (IC₅₀ =7.67 ± 0.61 μg/mL) and inhibited cyclooxygenase activity (IC₅₀ = 594.33 ± 11.15 μg/mL), probably related to its high polyphenol content (192.64 ± 1.55 mg GAE/g E). HPLC-MS analysis revealed the presence of flavones and flavonols. Conclusively, the results of this study suggest that CF extracts exert anti-inflammatory and antibacterial effects by inhibiting cyclooxygenase and trypsin activities and altering bacterial cell membrane, suggesting the potential of CF in the treatment of bacterial infections and inflammatory disorders.