Assessment of the Antibacterial Activity of Crescentia cujete (Calabash) Ethanolic Fruit Extract Against Pseudomonas aeruginosa and Bacillus subtilis

Bacillus subtilis and Pseudomonas aeruginosa are bacterial species that are known to rapidly develop antibacterial resistance against antibiotics used to treat the infections that they cause. Crescentia cujete is a tropical tree that is considered as a herbal plant due to the secondary metabolites that it contains. This study seeks to determine if C. cujete ethanolic fruit extract is effective against B. subtilis and P. aeruginosa. This study also aims to compare if there is a difference in the effectivity of Crescentia cujete ethanolic fruit extract in four concentrations of 10 mg/mL, 5 mg/mL, 2.5 mg/mL, and 1.25 mg-mL, as well as its pure extract, against B. subtilis and P. aeruginosa. The study follows an experimental research design and utilizes the use of Kirby-Bauer (Disc Diffusion) method in gathering the data. Notably, results show that the C. cujete ethanolic fruit extract of different concentrations yield no zone of inhibition against the bacteria except for an insignificant zone of inhibition of pure extract against P. aeruginosa. The study concludes that C. cujete ethanolic fruit extract is ineffective against B. subtilis and P. aeruginosa due to lack of inhibitory activity. This study recommends the utilization of a different bacteria and another part of the plant. Additionally, the use of another extraction method may reveal different results