Antibacterial Activities of Citrullus lanatus Seed Extracts Against Staphyloccocus aureus and Pseudomonas aeruginosa Isolated from Wound Infections

Abstract

Watermelon seeds are from watermelon fruits, originally from vine plants that is rich in nutrients and bioactive compounds. This study aimed at assessing the antibacterial activities of Citrullus lanatus (Watermelon) seed extracts against Staphyloccocus aureus and Pseudomonas aeruginosa isolated from wound infections. Preliminary phytochemical screening of the ethanol and aqueous extracts of the watermelon seed was carried out using standard analytical methods. The two extracts were screened for antibacterial activities against S. aureus and P. aeruginosa isolated from wound swabs using agar well diffusion and broth dilution assay. The result of the phytochemical screening revealed the presence of saponins, steroids, tannins, phenol, quinines and terpenoids in the ethanol extract while saponins, steroids, quinones, phenol, terpenoids, and tanins were present in the aqueous extract. The inhibitory zone of the ethanol extract against S. aureus ranged between 12.25±3.18 mm to 15.50±0.71 mm while that of P. aeruginosa ranged between 12.80±0.00 mm to 15.25±1.06 mm at 50 and 100 (mg/mL) respectively. The inhibitory zone of the aqueous extract against the clinical isolate of S. aureus ranged between 11.50±0.71 mm to 11.75±2.87 mm at 50 and 100 (mg/mL) respectively, while P. aeruginosa had inhibitory activity of 14.40±0.00 mm at 100 mg/mL only. The Minimum Inhibitory Concentration and the Minimum Bactericidal Concentration, on the average were 50 mg/mL and 100 mg/mL respectively. The observed inhibitory activity of the ethanol and aqueous extracts of the seed against the clinical isolates could be due to the phytochemical components presence within the seed.