Study of Antibacterial Bioactive Compounds from Hibiscus sabdariffa and Syzygium aromaticum Extracts as an Alternative for Handling Methicillin Resistant Staphylococcus aureus (MRSA) Infections

Abstract

The global rise in infectious disease-related mortality, coupled with the uncontrolled use of antibiotics, has significantly contributed to the emergence of antibiotic-resistant bacteria. In response to this public health threat, plant-derived compounds have gained attention as promising, renewable antibacterial agents. This study aimed to investigate the antibacterial activity of clove ( Syzygium aromaticum ) and roselle ( Hibiscus sabdariffa ) flower extracts against Escherichia coli and Staphylococcus aureus . Both plants were extracted via the maceration method using a variety of solvents: ethanol, acetone, ethyl acetate, and distilled water (at room temperature and 100°C). The phytochemical screening revealed the presence of flavonoids, alkaloids, and tannins in all extracts, while saponins and glycosides were detected only in selected solvents. Antibacterial activity was evaluated using the disc diffusion and microdilution methods. The ethyl acetate extracts of both clove and roselle demonstrated the highest antibacterial efficacy, with inhibition zones of up to 32.5 mm and 25 mm for E. coli and S. aureus , respectively. The minimum inhibitory concentration (MIC) for clove extract was 41.7 mg/mL ( E. coli ) and 85.7 mg/mL ( S. aureus ), whereas roselle extract exhibited MIC values of approximately 33.4 mg/mL for both bacteria. These findings suggest that H. sabdariffa and S. aromaticum extracts contain significant antibacterial compounds—particularly flavonoids and phenolic compounds—and hold potential as natural alternatives to combat antibiotic-resistant bacterial infections.