Evaluation of phytochemical analysis and antibacterial potential of different solvent extracts of leaves and stem bark of Eucalyptus camaldulensis against selected pathogenic bacteria

Abstract

Research into the phytotherapeutic potentials of plants in the treatment of ailments has significantly received attention in recent years. Here, using two solvent extracts, we aimed to evaluate the antibacterial efficacy of phytochemicals extracted from leaf and stem bark of Eucalyptus camaldulensis against selected pathogenic bacteria. Solvent extracts of the leaf and stem bark of E. camaldulensis were prepared with methanol and chloroform. Phytochemical screening of crude extract was performed using standard methods. The leaf and stem bark extracts were tested for their antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Bacillus subtilis and Escherichia coli using the agar well diffusion method. Aqueous extract of plant (50 mg/mL) was used to prepare 50 mg/mL, 25 mg/mL, 12.5 mg/mL and 6.25 mg/mL concentrations of extract. Qualitative phytochemical analysis showed that in the methanolic leaf extract; cardiac glycosides, saponins, flavonoids and terpenoids were present while alkaloids and steroids were found in the chloroform leaf extract. Tannins were present in both extracts. Also, methanolic and chloroform stem bark extracts showed the presence of alkaloids, flavonoids, cardiac glycosides, steroids and tannins. Furthermore, both methanolic and chloroform extracts showed inhibitory effects at varying concentrations. Methanolic extract was effective on E. coli, B. substilis and P. aeruginosa at 25 mg/mL while chloroform extract exhibited inhibitory effect on E. coli at concentrations of 12.5 mg/mL and 6.25 mg/mL. Phytochemical screening of leaf and stem bark extract of E. camaldulensis revealed the presence of some active secondary metabolites; with the methanolic extracts showing more considerable antimicrobial effects.