Phytochemical analysis and evaluation of the antibacterial and antioxidant activities of the leaf extracts of Ficus sur Forssk

Ficus sur Forssk (family Moraceae) is one of the most commonly used medicinal plants in Ethiopia. This research reports the phytochemical constituents, antibacterial, and antioxidant activities of the methanol, acetone, and hexane leaf crude extracts of Ficus sur. The phytochemical constituents were analyzed using established standard procedures, with crude extracts prepared through consecutive maceration. The Folin-Ciocalteau method and aluminum chloride assay were employed to determine the quantity of total phenolic and flavonoid contents in the sample, respectively. The antioxidant activity was evaluated using a 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. Antibacterial efficacy was evaluated through the disc diffusion method against selected test bacteria, including gram-negative E. coli and K. pneumoniae, as well as gram-positive S. aureus and S. pneumonia. Qualitative screening of the crude extracts indicated the presence of steroids, saponins, flavonoids, tannins, alkaloids, terpenoids, glycosides, and phenols. Among the extracts, methanol extract demonstrated the highest total phenolic content of 87.323 ± 0.242 mg GAE/g dry weight, followed by acetone (70.233 ± 0.874) and hexane (65.418 ± 0.330). Similarly, the total flavonoid content was highest in the methanol extract (207.769 ± 5.588 mg QE/g), compared to acetone (187.256 ± 0.256) and hexane (157.0 ± 0.678). All extracts showed antioxidant activity, with IC50 values of 71.24 ± 4μg/mL for methanol, 83.70 ± 4 μg/mL for acetone, and 89.63 ± 4 μg/mL for hexane. Ascorbicacid served as the standard reference, exhibiting an IC50 value of 23.91 ± 4 μg/mL. The p-value (p < 0.001) confirmed a statistically significant difference in % inhibition among the groups (methanol, acetone, hexane, and ascorbic acid). The methanol extract showed more antibacterial activity against all tested pathogens, with the largest inhibition zone of 20 mm recorded against gram-positive S. aureus. Generally, the results showed that the crude extract, particularly the methanol extract, holds significant potential as an antioxidant and antibacterial agent.