Antibacterial properties of Alkaloid rich fractions obtained from various parts of Prosopis juliflora

The alkaloid rich fraction obtained from various parts of Prosopis juliflora were assessed for their antibacterial property using disc diffusion method on several Gram-negative and Gram-positive bacterial strains like E.coli, Staphylococcus aureus, Bacillus cereus, Psuedomonas putida, Klebsiella, Salmonella, Acinetobacter and Alcaligen. Strong antibacterial effect was shown by leaf, pod and flower extract, with MIC value ranging between 25μg/ml-100μg/ml. The extracts of leaves showed highest activity among all the plant parts. Klebsiella was found to be the most susceptible bacteria, whereas Acinetobacter and Alcaligen were the least susceptible. A comparison of zone of inhibition created by alkaloid rich fractions with that of standard antibiotics, ampicillin, tetracycline, chloramphenicol, oflaxacin, refampin, streptomycin and sulfa drug showed a comparable zone of inhibition. Growth of Acinetobacter and Alcaligen which were not inhibited by antibiotics, showed inhibition by the alkaloidal extracts, similarly a known ampicillin resistant E.coli strain was found to be inhibited by the plant extracts. Alkaloids present in the extracts were analysed by DART-MS. DART-MS analysis of the alkaloid rich fractions showed the presence of piperidine alkaloids.