Antibacterial Activity of Polyalthia longifolia Leaf Extracts against Staphylococcus aureus and Escherichia coli

Abstract

Polyalthia longifolia, commonly known as the masquerade plant, is a tropical evergreen plant with cultural and medicinal importance in Nigeria. This study used the disc diffusion method to analyze the antibacterial activity of Polyalthia longifolia leaves extracts against Staphylococcus aureus and Escherichia coli. The leaves were dried, grounded, and ethanolic and aqueous extracts were used for antibacterial screening against the test isolates. The test isolates were confirmed based on cell morphology, gram reaction, and biochemical tests. The leaf extracts were subjected to phytochemical screening for alkaloids, saponins, flavonoids, steroids, phytosterols, and tannins. Phytochemical analysis of the leaf extracts of Polyalthia longifolia revealed that the leaves of this plant contain alkaloids, anthraquinone, phenols acid, and saponins, while flavonoids and steroids were absent. The results of the antibacterial screening for aqueous and ethanolic extracts of the plant indicated that ethanol and aqueous extracts of the plant exhibited antibacterial activities with Minimum Inhibitory Concentration and Minimum Bactericidal Concentrations of 100mg/mL for both MIC and MBC. In conclusion, the leaves of the Polyalthia longifolia plant can be used as an alternative medicine for treating bacterial infections caused by Staphylococcus aureus and Escherichia coli.