HPLC-ESI/MS-Based Polyphenolic Profiling and Bioactivities of Pistacia atlantica and Oudneya africana: Antioxidant, Anti-Inflammatory, Antimicrobial, and Photoprotective Potential.

Pistacia atlantica and Oudneya africana are medicinal plants from arid Tunisian regions, traditionally used for their therapeutic properties. This study comparatively evaluated their ethanol and aqueous leaf extracts for phytochemical content and biological activities. LC-ESI-MS identified 19 bioactive compounds, including flavonoids and phenolic acids. The ethanolic extracts exhibited significantly higher total phenolic contents (119.80 ± 2.45 mg GAE/g DW for O. africana vs. 110.14 ± 3.50 mg GAE/g DW for P. atlantica). Antioxidant assays revealed that P. atlantica aqueous extract exhibited the strongest DPPH and ABTS scavenging activities (IC50 = 113 and 8.96 µg/mL, respectively), while O. africana ethanolic extract showed the highest ferric-reducing power (EC50 = 51.00 µg/mL). Antimicrobial testing showed the ethanolic extracts had MIC values as low as 0.625 mg/mL against Candida albicans and Escherichia coli, indicating superior efficacy. Photoprotective analysis revealed P. atlantica ethanolic extract possessed a higher SPF (47.4) than O. africana (39.9), suggesting greater potential as a natural sunscreen agent. These comparative results highlight the advantages of ethanolic extraction for maximizing bioactive compound yield and biological effectiveness and emphasize P. atlantica's stronger potential in antioxidant and photoprotective applications compared to O. africana. This study underscores the value of both species as sources of natural bioactive compounds, with differential properties suited to various medicinal and cosmetic uses.