In Vitro Antibacterial Activity of Crude Leaf Extracts of Pentas Schimperiana
Abstract
Background Medicinal plants are important sources of therapeutic agents, with approximately 80% of people in developing countries depend on traditional plant-based medicines. Pentas schimperiana (P. schimperiana) is traditionally used to the treatment of wound infections, malaria and gastrointestinal disorders. This study evaluated the in vitro antibacterial activity of crude leaf extracts of P. schimperiana. Methods P. schimperiana leaves were extracted by maceration using ethanol, chloroform, and n-hexane. Phytochemical screening was conducted, and antibacterial activity against Escherichia coli (E. coli) and Pseudomonas Aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), and Streptococcus pyogenes (S. pyogenes) was assessed using disk diffusion method, using kanamycin as the positive control. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated by broth dilution. Results Ethanol extraction produced the highest yield (4.08%). Phytochemical analysis revealed that ethanol extract contained all tested secondary metabolites, whereas chloroform and n-hexane extracts lacked alkaloids and anthraquinones; the n-hexane extract also lacked tannins and saponins. All extracts exhibited concentration-related antibacterial activity, with the highest activity generally observed at 200 mg/mL, the ethanol extract showed the greatest antibacterial activity, followed by n-hexane and chloroform extracts. MIC values ranged from 3.13–6.25 mg/mL for ethanol, 3.13–12.5 mg/mL for chloroform, and 12.5–25 mg/mL for n-hexane extracts, depending on the tested bacterial strain. Corresponding MBC values ranged from 6.25–12.5 mg/mL, 6.25–12.5 mg/mL, and 6.25–25 mg/mL, respectively. Conclusion P. schimperiana leaf extracts exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria, warranting further investigation of their active compounds and mechanisms of action. Graphical Abstract