P-89 The Study of Caffeine as Novel Quorum Sensing Inhibitor

Quorum sensing enables bacterial to communicate and at the same time control the gene expression in response to the cell density [1]. It is widely used by both gram-positive and gram-negative bacteria to regulate variety of bacterial physiological functions such as biofilm formation [2], bioluminescence [3], virulence factors [4] and swarming [5] which has been shown contribute to bacterial pathogenesis. With this knowledge, the use of QS inhibitor would be a particular value in treating bacterial pathogenicity and infections. In this work we have tested caffeine as quorum sensing inhibitor by using C.violaceum CV026 as a bioassay. This C.violaceum CV026 mutant strain is incapable of producing the purple pigment called violacein unless there are exogenous supply of N-hexanoylhomoserine lactone (C6-HSL) or other short chain AHL.The Inhibitory activity was measured by quantifying violacein production using a spectrophotometer. The results have revealed that Caffeine significantly reduced violacein production in a concentration dependent manner, indicating inhibition of quorum sensing. The presence of caffeine that exhibit anti-quorum sensing activity may be useful as the lead of anti-infective drugs