S. PRIYADARSHINI1 AND C.C. RATH
Abstract
The unprecedented rise in the bacterial infections has led to the exploration of novel antibiotics from endophytic microorganisms. In the present study endophytic bacteria isolated from Andrographis paniculata were screened for their antibacterial activities. Out of nine endophytic bacterial isolates a single isolate APNS1 showed significant antimicrobial activity against Bacillus sp., Salmonella sp., Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and MRSA. The zone of inhibition was shown to be maximum against MRSA (16.6±0.5 mm), followed by E. coli (16.3±0.5 mm) and P. aeruginosa (16.3±0.5 mm). The selected endophytic bacterium was identified as Mammaliicoccus sciuri by 16s rRNA gene sequencing with NCBI accession number PQ169006. The FTIR analysis of the ethyl acetate extract has shown several peaks within a range of 4000 cm-1 to 400 cm-1. The bands later interpreted as aromatic compounds, saturated aliphatic compounds (with CH2 and CH3 stretch) and carboxylic acid group. Bioactive compounds such as nhexadecanoic acid, malonic acid ester and beta-L- arabinopyranoside were identified through GC-MS analysis of the bacterial extract. These bioactive compounds with antimicrobial properties could be considered as potential ingredients for future pharmaceutical studies to develop novel antibiotics.