Phytochemical Screening, Antibacterial Effects and Antioxidant Activities of Ethanolic Stem Bark Extract of Pterocarpus erinaceus

Background and Objective: In Nigeria, Pterocarpus erinaceus is used as a medicinal plant to treat many illnesses ranging from malaria, ulcer, cough and fever, to rheumatism. The antioxidant, antimalaria, antiulcerogenic and antibacterial properties of stem bark, leaves and root of P. erinaceus have been studied. The aim of this study was aimed to determine the phytochemical compositions, antibacterial effect and antioxidant activity of the stem bark of Pterocarpus erinaceus. Materials and Methods: A Gas Chromatography Flame Ionization Detector (GC-FID) instrument was used for the analysis and quantification of phytochemicals present in the ethanolic stem bark extract of P. erinaceus. The antibacterial test was carried out using the agar well method against standard bacteria: Staphylococcus aureus, Bacillus subtilius, Pseudomonas aeruginosa and Escherichia coli the antioxidant activity was carried out by evaluating the DPPH scavenging activity. Results: The results of GC-FID analysis revealed flavonoids (38.98%), alkaloids (23.96%), steroids (4.86%), tannins (2.63%) and anti-nutrients (12.61%). The ethanolic stem bark extracts of P. erinaceus exhibited significant antibacterial activity against all bacterial strains selected (Bacillus subtilius, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) at all tested concentrations (100, 150 and 200 µg mL‾¹). DPPH scavenging activity was found to be 97.53% at a concentration of 1000 µg mL‾¹ and 24.26% at a concentration of 40 µg mL‾¹. Conclusion: The study revealed that the crude ethanolic extract of P. erinaceus stem bark contained pharmacologically active compounds and exhibited significant antibacterial activity and DPPH free radical scavenging activity in a concentration-dependent manner.