PHYTOCHEMICAL, ANTIOXIDANT, AND IN SILICO ANTIBACTERIAL STUDY OF SYZYGIUM MALACCENSE EXTRACT AGAINST FLUOROQUINOLONE RESISTANCE

Background: Antibiotic resistance amongst other antimicrobial resistance remains a growing threat to global health, with more than 23 million confirmed cases of bacterial infections reported between 2016 and 2023. Fluoroquinolone resistance by bacteria species causes community acquired or healthcare-associated urinary tract infections and intra-abdominal infections, with over 50% of infections in some parts of the world, particularly in Asia. This study assessed the phytochemical, in vitro antioxidant and in silico antibacterial properties of fresh (AAJ1) and fermented (AAJ2) aqueous extracts of Syzygium malaccense on selected biomarkers in fluoroquinolone resistance. Materials and Methods: Fruits of Syzygium malaccense were plucked from the orchards of Covenant University. The phytochemical constituents of AAJ1 and AAJ2 were assessed using phytochemical screening assays and gas chromatography-mass spectrometry (GC-MS). The antioxidant activity was investigated using 2,2-diphenyl-1-1-picrylhydrazyl radical (DPPH) and ferric reducing antioxidant power assays (FRAP). Molecular docking was carried out to compare binding affinities of standard inhibitors and phytochemical constituents of AAJ1 against selected biomarkers. Results and Conclusion: Qualitative phytochemical screening showed that Syzygium malaccense extract contains flavonoids, phenols, and anthocyanins. The total phenolic content for AAJ1 and AAJ2 was 0.750 ± 0.12 mgGAE/ml and 1.005 ± 0.31 mgGAE/ml respectively. The total flavonoids content for AAJ1 and AAJ2 was 1.037 ± 0.09 mgQE/ml and 1.092 ± 0.06 mgQE/ml respectively. GC-MS chromatogram revealed the presence of 12 compounds. The most abundant phytochemicals were 2-butoxy-ethanol (54%), Hexamethyl-cyclotrisiloxane (17%) and octamethyl-cyclotetrasiloxane (6%). Oleonitrile and 3-methyl-5-phenyl-1H-1,3,4-benzotriazepin-2(3H)-one exhibited higher binding affinity for DNA gyrase and topoisomerase IV than the standard inhibitors. In conclusion, certain phytochemicals present in Syzygium malaccense are likely to be potential therapeutic candidates for fluoroquinolone-resistant infections.