Phytochemical Studies, In-vitro Antibacterial Activities and Antioxidant Properties of the Methanolic and Ethyl Acetate Extracts of the Leaves of Anogeissus leiocarpus

Aims: To conduct a study on the antibacterial activity, phytochemical constituents and antioxidant properties that identify the medicinal potency of medicinal plants on the methanolic and ethyl acetate extracts of the leaves of Anogeissus leiocarpus. Antibacterial activity was determined by well diffusion method against four bacterial strains commonly associated with wound infections.

Study Design: Standard Phytochemical quantitative and qualitative test, DPPH radical scavenging activity and well diffusion method.

Place and Duration of Study: Department of Chemistry (Natural Products Laboratory), University of Cape Coast and Department of Microbiology, Korle-Bu Teaching Hospital, University of Ghana, between March 2012 and January 2013.

Methodology: Standard chemical procedures were used to identify phytoconstituents present in the plant extracts. DPPH radical scavenging assay and well diffusion method were used to determine antioxidant and antibacterial activity respectively. UV-spectrophotometry was employed to further quantify the phenolic and flavonoid content.

Results: The extracts showed pronounced activity against all the bacterial strains tested.

Ethyl acetate exhibited the maximum zone of inhibition against Klebsiella pneumonia while the Methanol extract exhibited the maximum zone of inhibition against Citrobacter sp. All the extracts showed higher sensitivity against Gram negative bacterial strains than the Gram positive bacterial strain used in this study. Phytochemical study was performed by using standard methods. Quantitative estimation of bioactive phytoconstituents showed that the plant contains alkaloids (152.0 ± 0.1 mg/g), phenolics (1294.81 ± 3.0 mg/g), flavonoids (330.7 ± 3.0 mg/g) in the methanol extract and alkaloids (80.20 ± 0.0 mg/g), phenolics (616.5 ± 4.4 mg/g), flavonoids (202.5 ± 4.0 mg/g) in the ethyl acetate extract respectively. In similar fashion, the results from the scavenging activity against 1,1-diphenyl-2-picryl hydrazyl radical (DPPH) and the Ferric reducing antioxidant power (FRAP) assay for both extracts were high and concentration dependent.

Conclusion: The study clearly indicates that A. leiocarpus possesses significant antioxidant activity and antibacterial activity against the tested wound infectious bacterial strains. Hence constituents of the plant could be studied in the aim to be used in chemotherapy.