Unveiling the antimicrobial, biofilm inhibition, and photoprotective potential of Bupleurum falcatum L. for dermatological applications.

Bupleurum falcatum L. is known for its therapeutic properties, especially in treating fever, inflammation, and infectious diseases. However, its potential for dermatological applications remains mainly unexplored. Thus, the present study explores antimicrobial potential of B. falcatum against biofilm-associated infections, antibiotic-resistant strains, and UV-induced skin damage. This aligns with the growing interest in natural products as sources of bioactive compounds with skin-protecting features. Herein, we employed maceration (M) and ultrasound-assisted extraction (USA) at 50 Hz and 100 Hz (USA 50 and USA 100) to obtain extracts from aerial parts of the plant. Chemical profiling was performed using UHPLC. Antimicrobial activity, biofilm inhibition, EPS and eDNA production were assessed using microdilution test, crystal violet, Congo red, and eDNA assays, respectively. Cytotoxicity and photoprotective effects were evaluated on human keratinocytes using the MTT assay. Chemical analysis identified 64 compounds, including benzoic and cinnamic acid derivatives, flavonoid glycosides, and saikosaponins. Extracts showed strong antimicrobial activity against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MIC as low as 0.5 mg/mL). The M extract displayed moderate biofilm inhibition and reduced eDNA production. Cytotoxicity assays confirmed safety on keratinocytes, while M and USA 100 extracts demonstrated photoprotective effects. B. falcatum extracts showed promising potential in addressing biofilm-associated infections, antibiotic resistance, and UV-induced skin damage. See also the graphical abstract(Fig. 1).