Anti-quorum sensing potential of nonspecific lipid transfer protein/bi-functional trypsin alpha-amylase inhibitor isolated from Eleusine coracana (L.) Gaertn

Small plant defense proteins known as nonspecific lipid transfer proteins (nsLTPs) possess diverse biological activities and promising therapeutic potential. Eleusine coracana (finger millet) is a nutrient-rich cereal crop recognized for its diverse bioactive compounds and potential health promoting properties. In this study, the proteins were extracted, dialyzed and four fractions were obtained by RP-HPLC. Further, the LC-MS/MS based peptide mass fingerprinting identified a bioactive nsLTP in the fraction 1. The pure nsLTP showed strong anti-quorum sensing activity against Pseudomonas aeruginosa and dual inhibitory activity against α-amylase and trypsin. At the minimum inhibitory concentration, the nsLTP reduced biofilm formation by 77 %, along with significant inhibition of exopolysaccharide, protease, elastase, and pyocyanin production. Confocal laser scanning microscopy confirmed biofilm disruption, while RT-qPCR analysis revealed the downregulation of quorum-sensing associated genes. Molecular docking further suggested favorable interactions of nsLTP with the quorum-sensing autoinducer 3-oxo-C12-HSL and the LasI, LasR, and LasA proteins, supporting its potential anti-quorum sensing mechanism. These results demonstrate the novelty of E. coracana derived nsLTP as a multifunctional bioactive protein with enzyme inhibitory and anti-virulence characteristics, indicating as a natural therapeutic candidate for managing P. aeruginosa infections and battling antibiotic resistance.