Antibacterial Activity of Endophytic Bacteria from Stem Bark of Dialium guineense (Wild).

Dialium guineense or African black velvet tamarind, is a common tree in West Africa whose parts have been established for its antimicrobial and therapeutic properties. In this study, the stem bark of the plant was accessed for endophytic bacteria and their activity against common clinical isolates were evaluated. Isolation of bacteria endophytes from the stem bark of the plant was achieved by surface sterilization using 70% ethanol and 2% sodium hypochlorite before aseptically cutting into small sizes of about 3.5 - 4.0 mm, plated on nutrient agar and then incubated for 24 hours. Pure isolates of the endophytes were obtained and identified macroscopically and molecularly by depositing 16SrRNA sequences of all the isolates on NCBI website. The endophytic bacteria isolates belong to the genera Pseudomonas, Halopseudomonas, Burkholderia, Streptococcus and Bacillus. Antibacterial activity carried out with the crude extracts of all endophytic bacteria isolates revealed that the bacteria endophyte mSB2 of the genera Halospeudomonas, had the most clearer zones and diameter of inhibition against all test isolates with zones ranging from 9.0 ± 0.35 mm to 35 ± 0.5 mm; hence, the extract from mSB2 was most active and posed effective antibacterial activities. This study established a fact that Dialium guineesnse harbors bacteria endophytes with active metabolites against common disease-causing organisms. Keywords: Dialium guineense, Endophytic bacteria, Stem bark, Antibacterial activities, Metabolites. DOI: 10.7176/JNSR/14-12-04 Publication date: September 30 th 2023