Direct bioautography and gas-chromatography-mass spectrometry profiling of ethanolic extracts of leaves of Ipomoea marginata (Desr.) Verdc. against select oral microorganisms

Antimicrobial resistance is a global concern in management of bacterial infections.Plant based therapeutics have immense potential in combating bacterial infections without causing antimicrobial resistance.The oral cavity harbours a diverse and well-structured microbiome.Streptococcus mutans (S. mutans) is a highly virulent microorganism causing tooth decay and Treponema denticola (T.denticola) is known to cause inflammation of the gums termed gingivitis.Though, mouth washes such as chlorhexidine (CHX) are having proven antibacterial action, recent literature has reported oral dysbiosis and development of bacterial resistance on long term use of these mouth washes.Identification of the bioactive compounds of herbal extracts and proving their antibacterial action against pathogenic oral microorganisms can pave way for novel therapeutic oral formulations.This study was designed to identify the bioactive compounds of ethanolic extract of leaves of Ipomea marginata (Desr.)Verdc.by gas chromatography-mass spectrometry (GC-MS) profiling and antibacterial screening of the bioactive fraction present by direct bioautography.GC-MS analysis of the leaves of ethanolic extract of I. marginata was performed on a GC-MS equipment.Direct bioautography of the bioactive compounds was carried out using Mueller Hinton agar (MH agar) plate covered with sterile lens paper and the dried TLC plates with matching spots placed aseptically on it.Two compounds; namely, triethyl citrate and phenol 3,5 -bis (1,1-dimethylethyl) were eluted using GC-MS.On performing direct bioautography, S. mutans and T. denticola showed antibacterial activity and zone of inhibition similar to that of standard CHX.The results of the study indicated the two bioactive compounds present in ethanolic extract of leaves of I. marginata exhibited antibacterial property against S. mutans and T. denticola.