Abstract

The widespread distribution of Crinum macowanii across the African continent has entrenched the plant’s medicinal usage in treating diverse diseases. While its phytochemistry is well established, its microbial symbionts and their utility have not been described. As such, five bacterial endophytes, viz. Staphylococcus species C2, Staphylococcus species C3, Bacillus species C4, Acinetobacter species C5 and Staphylococcus species C6 were isolated from fresh C. macowanii  bulb and their phenotypic and genotypic profiles verified by Gram staining and 16S rRNA gene sequencing; respectively. The latter was used to construct a phylogenetic tree that showed similarities (higher than 50 bootstrap values) among the endophytic bacterial isolates. Chemical analysis of bacterial endophytes was done by extracting the crude extracts of each endophyte. Antibacterial activity of each endophyte was performed against a few selected bacterial pathogenic strains (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Bacillus cereus) using the disk diffusion method with Streptomycin used as a positive control. The crude extracts of all the endophytes showed no bioactivity against K. pneumoniae, though the inhibition was observed against E. coli, P. aeruginosa, S. aureus and B. cereus. These results suggest that crude extracts of endophytic bacteria from C. macowanii have the potential to be used as antimicrobial agents.

Key words: Antibacterial activity, Crinum macowanii, endophytes, phylogentic analysis.