Black sea cucumber (Holothuria atra Jaeger, 1833) extracts rescues Pseudomonas aeruginosa-infected Caenorhabditis elegans via reduction of pathogen virulence factors and enhancement of host immunity
A strategy to circumvent the problem of multidrug resistant pathogen is the discovery of anti-infectives targeting bacterial virulence or host immunity. The black sea cucumber (Holothuria atra) is a tropical marine sea cucumber species traditionally consumed as remedy for many ailments. There is a paucity of knowledge the anti-infectives capacity of H. atra and the underlying mechanisms involved. The objectives of this study were to utilize the Caenorhabditis elegans-P. aeruginosa infection model to assess the anti-infective properties of H. atra. A bioactive H. atra extract and fraction was demonstrated to have the capacity of promoting survival of C. elegans during a customarily lethal P. aeruginosa infection. The same entities also attenuated the production of elastase, protease, pyocanin and biofilm in P. aeruginosa. Treatment of infected transgenic lys-7::GFP worms with H. atra fraction restored the repressed expression of lys-7, a defense enzyme, which indicates improved host immunity. QTOF-LCMS analysis revealed the presence of aspidospermatidine, an indole alkaloid and inosine. Collectively, our finding shows that H. atra possess anti-infective properties against P. aeruginosa infection through inhibition of pathogen virulence and eventually, the restitution of host lys-7 expression.