DETECTION OF ANTI-QUORUM SENSING ACTIVITY OF ROSEMARINUS OFFICINALIS AND VALERIANA OFFICINALIS USING MICROBIAL BIOSENSOR STRAIN

Quorum-sensing is a phenomenon in which bacteria exhibit several density dependent phenotypes. Quorum-sensing is achieved through production of auto – inducer which on acquiring a threshold concentration, activates the genes, bringing into effect the concerned phenotypes. Ayurvedic medicinal plant extracts are being used to treat a plethora of infectious disease and are known to be rich in phytochemical compounds. This work aims at screening Rosemarinus officinalis and Valeriana officinalis for their anti- quorum-sensing activity using microbial biosensor strains which includes Pseudomonas chlororaphis (aureofaciens) 30-84, S. aureus agr P3::blaZ pRN8826 and C. albicans 10231. Initially, the medicinal plant extracts are made and minimum inhibitory concentration (MIC) of these extracts is determined. Qualitative phytochemical tests are performed with the extracts in order to find out the phytochemical present in these medicinal plant extracts. This is further followed by reporter assays for the detection of anti-quorum sensing activity involving the microbial biosensor strains and then quantification of the activity. The Rosemary leaves and the Valeriana roots containing alkaloid, catecholic tannin and flavonoid as its active component respectively posses quorum sensing inhibitor. Valeriana roots shows an anti quorum sensing activity against Pseudomonas chlororaphis 30-84 and C. albicans 10231. On the other hand Rosemary leaves have an anti quorum sensing activity against all the three microbial biosensor strains used. The finding of this study suggests that these plants can be used in combination with conventional antibiotics for therapeutic purposes.