Screening of selected medicinal plants for its potential to inhibit biofilm formation and virulence factor production by Pseudomonas aeruginosa PAO1 Rajeswari M.* Assistant Professor, Department of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore - 641043, Tamil Nadu, India *Corresponding Author E-mail: rajeshwari_bc@avinuty.ac.in
Online Published on 5 February, 2024. Abstract Pseudomonas aeruginosa is a virulent human pathogen which exerts its pathogenicity with the aid of various factors namely biofilm formation, virulence factors production, and motility mechanisms. Increase in the rate of resistance mechanisms against conventional methods of treatment has led to the discovery of alternative approaches to treat its pathogenesis associated ailments in humans. In this study, we have screened four medicinal plants namely Amomum subulatum, Holarrhena pubescens, Laurus nobilis, and Punica granatum for their antibiofilm and antiquorum sensing activity. Initially, the plants were extracted using methanol and their minimum inhibitory concentration (MIC) were determined by microbroth dilution method. The MIC of A. subulatum, H. pubescens, L. nobilis, and P. granatum was found to be 4mg/ml, 0.5mg/ml, 6.25mg/ml, and 25 mg/ml, respectively. Further, at sub-MICs, all the four extracts inhibited the formation of biofilm in P. aeruginosa PAO1 without affecting its growth. The highest inhibitory percentage on biofilm formation (67%) was exhibited by L. nobilis. The impact of extracts on exopolysaccharide (EPS) production was investigated which revealed that production of EPS decreased with increase in sub-MICs. The influence of extracts on production of virulence factors in P. aeruginosa PAO1 namely pyocyanin, rhamnolipids, and alginate were evaluated. Among the four extracts, A. subulatum exhibited the maximum inhibitory activity at its sub-MIC of 2 mg/ml on production of pyocyanin, rhamnolipids, and alginate. Finally, swimming and swarming motility behaviors in P. aeruginosa PAO1 was also affected on treatment with sub-MICs of the plant extracts with greatest effect shown by A. subulatum and P. granatum. Hence these findings may provide an underlying knowledge on identification of new antibiofilm and antiquorum sensing compounds for treating biofilm-related infections caused by P. aeruginosa. Top Keywords Pseudomonas aeruginosa, Plant extracts, Crystal violet staining, Pyocyanin, Rhamnolipids, Alginate, Swimming motility, Swarming motility. Top |