Anti-Quorum Sensing Efficacy of Mangifera indica Kernel Extract against Biofilm Formation in Pseudomonas aeruginosa

Abstract

P.aeruginosa (PA) is responsible for causing both acute and chronic infections in immune compromised individuals. Multi-drug resistance among them is a very common phenomenon due to their complex biofilm forming nature enabling the bacteria to evade antibiotic treatment as well as human immune defence mechanism. In the present study, biofilm inhibition in P.aeruginosa was analysed using mango peel (MPE) and kernel extract (MKE). MKE has a greater content of phytoconstituents such as tannin and phenol (1.6458± 0.07 mg g-1 TAE; 1.56± 0.007 mg g-1 GAE) than MPE (0.2938± 0.05 mg g-1 TAE; 1.31± 0.003 mg g-1 GAE). MKE at 12.5-200μg ml-1 showed significant reduction of biofilm (70-75%) and quorum sensing (QS) (35-65%) against PA and C. violaceum whereas MPE showed only 20-23% of biofilm and 5-15% of QS inhibition. Epi-fluorescence and CLSM micrographs demonstrated the efficacy of MKE in inhibiting surface adhesion and biofilm thickness. As a result, MKE at 50μg ml-1 (1/4 BIC) suppressed PA biofilm formation without impairing planktonic cell growth, reducing the possibility of the emergence of multi-drug resistance. Additionally, MKE inhibited the production of pyocyanin and had a negative impact on swarming and twitching motility. Eight distinct phytochemicals were found in MKE after it was characterised, but 2(3h)-furanone, 3-(15-hexadecynylidene)dihydro-4-hydroxy-5-methyl, 4r-(3e,4.alpha.,5.beta) represented 33.75% of the peak area and is presumed to be the antibiofilm compound.