Spectral analysis and antibacterial potential of bioactive principles of Sargassum crassifolium J. Agardh from Red sea of Jazan origin

Seaweeds have been focused as potential and promising resources to develop novel pharmaceuticals. The present study was aimed to investigate the bioactive principles of Sargassum crassifolium (S. crassifolium) through organic solvents methanol and petroleum ether extractions individually. The present study also extended to determine the antibacterial potentiality of the bioactive principles from methanolic extract (ME) and petroleum ether extract (PEE) of S. crassifolium against a set of human pathogenic bacteria. Gas chromatography-mass spectrometry (GC–MS) and Fourier transform infrared spectroscopy (FT-IR) analysis of the ME and PEE were exhibiting unique bioactive constituents. The antibacterial effect of ME and PEE were showed the moderate spectrum of activity when compared to the standard streptomycin disc against the screened human pathogenic bacteria. The bacterial sensitivity to the ME was sequenced as Bacillus subtilis > Pseudomonas aeruginosa > Escherichia coli > Klebsiella pneumoniae > Staphylococcus aureus > Streptococcus pyogenes. Furthermore, the spectrum of activity of PEE was showing more or less similar pattern of action with almost equal potency. The spectrum of activity of PEE extract was in the order Bacillus subtilis > Pseudomonas aeruginosa > Escherichia coli > Staphylococcus aureus > Streptococcus pyogenes > Klebsiella pneumoniae.