Abstract
A biological screening of the activity of Justicia secunda Vahl. extracts and fractions against several Gram-positive and Gram-negative bacterial strains of Enterobacteriaceae and in the brine shrimp Artemia salina Linn. assay, is reported. The ethanol extract of the aerial parts of the plant was sequentially partitioned with n -hexane (FHX) and chloroform (FCH), remaining a water solution (FOH). All fractions showed bactericidal activity against Gram-positive bacteria Bacillus cereus (ATCC 9634) and Staphylococcus aureus (ATCC 6538P), while they were inactive against Gram-negative strains Escherichia coli (ATCC 0389), Klebsiella pneumoniae (ATCC 10031), Proteus vulgaris (ATCC 9920) and Salmonella typhimurium (ATCC 14028). The water-soluble fraction (FOH) showed activity in the brine shrimp bioassay, yielding a LC 50 value of 37.93 µg/ml. The original FHX and FCH fractions were subjected to short column chromatography. Three fractions from FHX and four fractions from FCH were active against Gram-positive bacterial strains, and they were inactive against the Gram-negative ones.