Abstract
Upper respiratory tracts infections caused by Streptococcus pyogenes is one among the predominant infections. Biofilm formation is the major cause of bacterial pathogenesis and antibiotic resistance. Medicinal plants are widely studied for their inhibitory effect against biofilm forming S. pyogenes. The present study involved the antibiofilm activity of synergistic methanolic extracts of Leucas aspera, Vitex negundo and Gymnema sylvestre (LVG) against S. pyogenes isolated from pharyngitis patients. Minimum Inhibitory Concentration (MIC), Biofilm Inhibitory Concentration (BIC), antibacterial activity, growth curve, light microscopy and GC-MS analysis were performed. Results revealed significant (p<0.05) biofilm inhibition percentage (94.2%) against S. pyogenes at sub-MIC. The GC-MS analysis revealed the presence of thirty tree compounds among which n-hexadecanoic acid, phytol isomer, and octadec-9-Enoic acid were predominant. Microscopic analysis showed dose dependant reduction in the biofilm architecture as compared to control. To our knowledge this study is the first report on the synergistic antibiofilm activity of Leucas aspera, Vitex negundo and Gymnema sylvestre emphasizing on its importance as an alternative medicine. However, it remains for the further study to elucidate the active principles of the combined plant extracts against biofilm forming S. pyogenes.