Antiquorum Sensing Potential of Andrographolide from Andrographis paniculata in Vibrio harveyi

The recently discovered cell-cell communication system through signaling molecules among bacterial pathogens is known as Quorum sensing. It is well known for bacterial virulence, antibiotic resistance and biofilm production. Microbial pathogenicity is reduced by inhibiting the quorum sensing activity in all infections caused by bacteria. In this present study the compound Andrographolide which is present as a secondary metabolite in Andrographis paniculata was assessed for its anti quorum sensing activity against acyl homoserine lactone (AHL)-dependent biofilm formation and bioluminescence production in Vibrio harveyi (MTCC 7771). The Andrographolide showed a concentration dependent (100 μg/ml) reduction in biofilm production to a level of 97% and reduction of bioluminescence at the level of 98% in Vibrio harveyi (MTCC 7771) and compared with the standard Andrographolide (sigma aldrich). Light microscopic analysis and Microtiter plate assay further confirmed the reduction in the biofilm forming ability of Vibrio harveyi (MTCC 7771) when treated with andrographolide. The andrographolide at its standard concentration showed antibacterial effect on Vibrio harveyi(MTCC 7771).