Chemical Composition and Some Biological Activities of the Methanolic Encephalartos ferox Fruit Extract

Background: Although literature reports the therapeutic properties of Encephalartos ferox, there are limited pharmacological studies of its fruit. Objective: This study sought to evaluate the antibacterial, antioxidant, anti-quorum sensing and in vitro cytotoxic activities of the methanolic E. ferox fruit extract. Methods: The chemical constituent of the methanolic fruit extract was analysed using gas chromatography-mass spectrometry. Antibacterial activity of the extract was investigated against Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 10102), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) using the broth dilution method. The standard 2.2-diphenyl-1-picrylhydrazyl (DPPH) and 2.2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to evaluate the scavenging activities of the extract. Anti-quorum sensing activity was assessed against biosensor strain- Chromobacterium violaceum (ATCC 12472). Cytotoxicity in HepG2 cells was investigated using the tetrazolium-based colorimetric (MTT) assay. Results: The extract revealed eight volatile compounds with cis-Vaccenic acid (87.06%) and 9-Octadecenoic acid, 1,2,3-propanetriyl ester (5.21%) as the major components. Antibacterial activity against all tested strains with minimum inhibitory concentration range of 1.56 - 12.5 mg/mL was observed. The DPPH and ABTS assays demonstrated scavenging activities with the median inhibitory concentration (IC₅₀) values of 0.09 mg/mL and 0.003 mg/mL, respectively. The extract also displayed strong anti-quorum sensing activity with 93% inhibition of violacein production at 25 mg/mL. A half maximum inhibitory concentration (IC₅₀) of 5370 μg/mL was computed in HepG2 cells. Conclusion: The extract has potential to be used as a source of therapeutic compounds in pharmaceutical applications.