||The present investigation was undertaken to isolate and fractionate flavonoids from in vitro cell culture of the liverwort Marchantia linearis Lehm and Lindenb., a poorly documented bryophyte and its mode of bactericidal potentiality. Initially, callus culture was initiated from spores in MS/5 media containing growth regulators. From suspension culture flavonoids were isolated and fractionated by HPLC PAD chromatogram, which revealed the presence of a pool of active compounds. In vitro time-kill assessment data supports the MBC and MKC. Remarkable leakage of reducing sugar and high leakage of nucleic acid and protein were observed at different concentration of flavonoid. Further, respiratory chain enzyme dehydrogenases showed lower profile in the treated bacterial strains. SEM data substantiated the bactericidal potentiality. Thus, the flavonoids of M. linearis may be a potent candidate for the in vivo biological control of pathogenic bacteria. Further studies are warranted to purify the lead molecule and to elucidate the molecular mechanism of bactericidal action.