Phytochemical analysis and antibacterial activity of trema orientalis (Ulmaceae) stem bark extracts on respiratory tract bacteria

Abstract

Respiratory tract infection causing micro-organisms are becoming increasingly resistant to common antibiotics. This negative health trend has rekindled interest in the search for plant constituents as sources of antibacterial agents that can be used for the treatment of respiratory tract infectious diseases. The objective of this study is to carry out phytochemical analysis and antibacterial activity of Trema orientalis stem bark extracts on respiratory tract bacteria. Phytochemical screening and thin layer chromatography (TLC) were done on T. orientalis stem bark extracts obtained by successive extraction with n-hexane, chloroform, ethyl acetate, methanol and water. Also, the antibacterial activity of the extracts were carried out using clinical isolate of Pseudomonas fluorescens, Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, and Proteus mirabilis. The most active chloroform extract was further screened by TLC bioautography using the test microorganisms. The phytochemical screening of the stem bark extracts revealed the presence of flavonoids, steroids, terpenoids, saponins and tannins. The chloroform extract inhibited the growth of all the test organisms especially E. coli and K. pneumonia. The minimum inhibitory concentration (MIC) for E. coli and K. pneumonia were 0.4 mg/mL and 1.6 mg/mL respectively; while the minimum bactericidal concentration (MBC) was 0.8 mg/mL for E. coli and 12.8 mg/mL for K. pneumonia. This study has justified the traditional use of this plant for the treatment of respiratory tract infections.