Phytochemical Profiling and Biological Activities of Extracts from Three Fern Species: Adiantum raddianum, Nephrolepis exaltata, and Phlebodium aureum

Ferns represent one of the most diverse groups of vascular plants, widely distributed across various ecological habitats. They are recognized as valuable sources of bioactive secondary metabolites with significant biological activities. The present study aimed to investigate the phenolic profile, antioxidant and antimicrobial activities of three fern species, Adiantum raddianum (AR), Phlebodium aureum (PA), and Nephrolepis exaltata (NE), by using three extraction solvents (methanol, acetone and water) applied to dried and fresh fern leaf material. A total of 20 phenolic compounds were identified by HPLC-DAD-ESI-MS, including hydroxybenzoic acids, hydroxycinnamic acids, and flavonols being the abundant class. Additionally, antioxidant capacity was noticed in the aqueous extracts of dried P. aureum (DPPH: 4.07 ± 0.01 µmol TE/g extract) and A. raddianum (DPPH: 4.05 ± 0.02 µmol TE/g extract), which also exhibited ABTS antioxidant capacity of 6.10 ± 0.01 and 5.99 ± 0.23 µmol TE/g extract, respectively. Fern extracts demonstrated selective bioactivity, showing effectiveness against Gram-negative and Gram-positive bacteria and fungal strains. A. raddianum exhibited consistent MIC values across solvents, while N. exaltata demonstrated notable antifungal activity, particularly against Candida species. The current findings highlight the importance of ferns as alternative sources of bioactive compounds and support their continued investigation within pharmacological and phytochemical research.