Analysis of Quorum Sensing Inhibition and Phytochemicals in Different Extracts of Garlic

Usage of Allium sativum L. bulb (Amaryllidaceae) against the pathogenesis of Pseudomonas aeruginosa is an emphasized approach. However, biological response and safety of herbal extracts depend upon the processing methods and solvents used in preparation. In this study, various garlic bulb extracts (ethanol, ethyl acetate, methanol, acetone, chloroform, toluene, raw and heated) were prepared and examined for their quorum sensing inhibitory (QSI) potential in terms of reduction in quorum sensing signal molecules(QSSMs) production, biofilm formation and motility exhibited by P. aeruginosa. Out of all these, toluene extract of garlic (TGE) in its sub-MIC showed highly significant reduction in production of QSSMs (80%), biofilm formation (5 folds, p<0.01) and three forms of motilities (p<0.05) as compared to P. aeruginosa grown in the absence of any of the extracts. Further, phytochemical profiling of extracts indicated a maximum abundance of thiosulfinates (THS) in TGE and possibility of relevance of saponins in motility.