Anti-biofilm Activity of Extracts of Caryota no in Drosophila melanogaster Infected with Pseudomonas aeruginosa

Objectives: To investigate the anti-biofilm activity of the n-hexane and methanol extracts of Caryota no (CN) seeds against Pseudomonas aeruginosa (PA) infection in D. melanogaster.

Study Design: Experimental design.

Place and Duration: Sample: African Centre of Excellence for Phytomedicine Research and Development, University of Jos, Jos Plateau State Nigeria between June 2018 and February 2019. Methods: 20 flies (1-3 days old) were pricked in the dorsolateral aspect of the abdomen with a modified fly needle dipped in biofilm forming strain of P. aeruginosa inoculum and left to recover and then transferred into the appropriately labeled vials which include different doses of the extracts or those in various control conditions. This process was done in 2 batches of flies treated with extracts prior to infection and flies treated with extracts after infection. The flies were monitored for survival for 72 hours. Mortality records were taken 6 hourly during this period, and the percentage of death determined in each group. The statistical difference among test groups was presumed at P < .05.

Results: The result of n-hexane Caryota no extract showed significantly (P < .05) improved survival (or decreased mortality) when used prophylactically and in curative assays compared to the control. The 400 mg of the n-hexane extract seemed to be the optimal concentration in both prophylactic and curative assays since it showed the least percentage deaths (50% and 43%) respectively. The methanolic extract exhibited a nonsignificant (P > .05) decrease in percentage death prophylactically but direct significant (P < .05) dose-dependent reduction in percentage deaths than the control in the curative studies with the 400 mg dose also showing the least deaths (47%).

Conclusion: The results suggest that both methanolic and n-hexane extracts of Caryota no have potentials as antibiofilm agents.