Discovery of secondary metabolites from Avicennia marina to inhibit the anti-oxidant and anti-biofilm activities of biofilm forming bacteria

The present study is concentrated on screening of phytochemical and bioactive compounds from marine mangrove plant of Avicennia marina (A. marina). The plant extract was purified by soxhlet extraction process, and the available phytochemicals, bioactive compounds and other organic compounds were confirmed by LC-MS analysis. Subsequently, the antioxidant and DPPH scavenging activities of the A. marina extract was shown 79 % and 88 % at 500 µg/mL concentrations were observed respectively. Further, the antimicrobial efficacy of A. marina extract was shown 22 and 26 mm and 18 and 24 mm zones of inhibition against K. pneumoniae, A. baumannii, S. aureus and Enterococcus sp. at 500 µg/ml concentrations by agar well diffusion method. In addition, the liquid medium based bacterial inactivation was clearly observed with 78 %, 89 %, 81 % and 90 % at 500 µg/ml concentration. Furthermore, the biofilm inhibition concentration and exopolysaccharide degradation effect of A. marina extract indicated that the bacteria were completely arrested and the inhibition range of 92 %, 88 % 84 % and 90 % and 89 %, 94 %, 90 % and 86 % were observed respectively. Finally, the result evidences were clearly indicated that the mangrove plant A. marina was excellent antimicrobial inhibitor and also future drug discovery plant to fight against some important multi drug resistant pathogens.