Phytochemicals Analysis, Antioxidant, and Antibacterial Activities from Fraction of Pneumatopteris callosa Leaves Extract

Many ferns contain metabolites with potential pharmaceutical applications. One of the ferns used in Indonesia as the herb is Paku Lindung (Pneumatopteris callosa). This fern was traditionally used to treat fever and hypertension. This study aimed to analyze the antioxidant and antibacterial activities of fractions from the ethanolic extract of Paku lindung by annotation of its phytochemicals. The ethanolic extract of Paku lindung was obtained using the maceration method at room temperature, and then it was fractionated successively using hexane, dichloromethane, and ethyl acetate solvents. The analysis of metabolites was conducted using the Liquid Chromatography-High Resolution Mass Spectrometer (LC-HRMS) with positive and negative ion methods, while the antioxidant activity was carried out using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, and the antibacterial activity was evaluated using the microdilution method. Total phenolic contents (TPC) and total flavonoid contents (TFC) were also determined in this study. The results revealed that ethyl acetate fraction (F3) had the highest activity toward radical DPPH with IC50 of 452.68±5.38 µg/mL, while the antioxidant activity of aqueous fraction (F4) revealed IC50 of 510.57±2.57 µg/mL. The antibacterial activity exhibited that crude ethanolic extract has the highest activity against both bacteria tested, Escherichia coli and Bacillus subtilis, with MIC50 values of 0.54 and 0.45 mg/mL, respectively. The LC-HRMS of F3 fraction identified 19 secondary metabolites belonging to the flavonoid, phenolic, fatty acid, chalcone, amide, and carboxylic acid. The biological activities and identification of metabolites contained in Paku Lindung leaf encourage the utilization of this plant in the food and medicinal industry.