EXPERIMENTAL INVESTIGATIONS ON CAMELLIA KISSI WALL. FOR ANTIOXIDANT, ANTI-QUORUM SENSING AND ANTI-BIOFILM ACTIVITIES

Abstract

Plants are known for their widespread biological activities with special reference to the use in folkloric medicines for the treatment of several diseases and metabolic disorders from ancient times. The presence of bioactive phytochemicals especially phenolic compounds, tocopherol, phytol etc. are responsible for the potential bioactivities of plants. In the present study, the radical scavenging potential of ethanolic extract of Camellia kissi wall. was evaluated. In addition, the effect of C. kissi wall. on quorum sensing (QS) associated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 was also investigated. The crude extract of C. kissi wall exhibited a significant antioxidant activity against DPPH and hydroxyl radicals with a scavenging percentage of 73.77 ± 3.58 and 75.3 ± 4.45 % respectively. The plant extract also significantly inhibited the QS regulated pyocyanin production, bacterial motility and recalcitrant biofilm formation in P. aeruginosa PAO1. The anti-biofilm activity was confirmed by confocal laser scanning microscopic (CLSM) analysis. The in vitro anti QS activity of C. kissi wall. was further confirmed by molecular docking studies specifically targeting the QS transcriptional regulatory protein, LasR. The present result will provide ample avenues to exploit medicinal plants in attenuating the QS regulated microbial infections and oxidative stress in the post-antibiotic era.