Bioactive components of plants are significant plant metabolites that are known to possess antimicrobial properties.The antimicrobial properties of flavonoids and saponins of ginger (Zingiber officinale) and garlic (Allium sativum) on Pseudomonas aeruginosa and Staphylococcus aureus were investigated.The isolates of P. aeruginosa and S. aureus were obtained from the Microbiology Laboratory, Department of Microbiology, Rivers State University, and their identities were confirmed using standard biochemical procedures. The extraction of crude saponin and flavonoid extracts was carried out using a standard method. The extracts were prepared into different concentrations and impregnated on sterile discs for antimicrobial susceptibility testing.The mean range of flavonoids in ginger was 211.74 ± 1.16–341.74 ± 1.16 g, while the range in garlic was 206.11 ± 0.63–399.65 ± 0.63 g. Saponins in ginger ranged from 2.5 ± 0.01 to 3.10% ± 0.01 % while in garlic, they ranged from 8.5 ± 0.02 to 12.77% ± 0.02%. The zone of inhibition of the saponin extract of ginger on P. aeruginosa ranged from 0.0 ± 0.0 to 11.5 ± 0.7 mm, while the range on S. aureus was 0.0 ± 0.0–18.0 ± 0.0 mm. The zone of inhibition of the flavonoid extract of the ginger on S. aureus was 0.0 ± 0.0–13.0 ± 1.4 mm, while the range on P. aeruginosa was 0.0 ± 0.0–12.0 ± 0.0 mm. The zone inhibition of the saponin extract of garlic on S. aureus ranged from 0.0 ± 0.0 to 13 ± 0.0 mm, while for P. aeruginosa it ranged from 0.0 ± 0.0 to 12.0 ± 1.4 mm. The zone of inhibition of the flavonoid extract of garlic on S. aureus ranged from 0.0 ± 0.0 to 14.5 ± 0.7 mm, while on P. aeruginosa, it ranged from 0.0 ± 0.0 to 18.5 ± 0.7 mm. The antibacterial effect of the extract was influenced by the concentration.The flavonoid extracts of ginger and garlic displayed better antibacterial activity on P. aeruginosa,while the saponin extract was best on S. aureus.

Keywords: Antimicrobial activity, Ginger, Garlic, P. aeruginosa, S. aureus