Disruption in Quorum-Sensing Circuits and Biofilm Matrix in Pseudomonas aeruginosa by Super-Critical COExtracted Oleoresins From Rauvolfia serpentina Seeds Rescue Caenorhabditis elegans Model of Infection.

Abstract

Rauvolfia serpentina roots are a therapeutic mainstay in traditional medicines and across time have been seamlessly integrated into the modern medical framework. Its seeds, however, are largely untapped. This study uniquely promotes bioresource valorization and sustainability by unveiling the therapeutic potential of R. serpentina seeds. With quorum sensing-driven remarkable survival strategies, drug-resistant Pseudomonas aeruginosa is a WHO-listed critical priority pathogen. Quorum sensing inhibitors have emerged as promising alternatives to conventional bactericidal antibiotics. Fatty acids (FAs) are also known to interfere with quorum sensing-mediated bacterial pathogenicity rather than exerting selective pressure. In the similar context, here we show the anti-pseudomonal and anti-quorum sensing potential of supercritical-fluid-(CO)-extract/oleoresins of R. serpentina seeds (RsSO). GC-MS/MS analysis identified long-chain FAs in RsSO. In Caenorhabditis elegans-P. aeruginosa infection model, RsSO demonstrated notable anti-infective property by rescuing host's survival, life span, progeny, behavior patterns and decreasing infection load. RsSO reduced growth and viability of P. aeruginosa and significantly attenuated key virulence factors, including alginate, pyocyanin, siderophores, rhamnolipids and proteases. RsSO interfered in quorum sensing and biofilm formation by downregulating the expression of lasA, rhlR, pelA and algD genes. Quorum sensing inhibition was further validated using the bioindicator microbial strain, Chromobacterium violaceum. Overall, the study highlights the therapeutic potentials of R. serpentina seeds, that are traditionally reserved for germplasm maintenance, for targeting pseudomonal virulence and pathogenesis.