Marine algae: screening for a potent antibacterial agent.

Area of Science:

• Marine Biology
• Microbiology
• Pharmacognosy

Background:

• Marine algae represent a rich source of bioactive compounds with potential pharmaceutical applications.
• Antibiotic resistance necessitates the discovery of novel antimicrobial agents from natural sources.

Purpose of the Study:

• To investigate the antibacterial activity of marine algae collected from Gujarat coastal regions.
• To identify potent algal species and their extracts effective against clinically significant bacterial strains.

Main Methods:

• Twenty-six marine algae were screened for antibacterial activity using acetone and methanol extracts.
• Agar disc diffusion and agar ditch methods were employed against *Bacillus cereus*, *Micrococcus flavus*, *Citrobacter freundii*, *Klebsiella pneumoniae*, and *Pseudomonas testosterone*.
• The most potent alga, *E. intestinalis*, was further extracted using various solvents and tested for Minimum Inhibitory Concentration (MIC).

Main Results:

• Methanol generally yielded more extractable compounds than acetone.
• *E. intestinalis* exhibited significant antibacterial activity, particularly against *Bacillus cereus* and *Klebsiella pneumoniae*.
• The petroleum ether extract of *E. intestinalis* showed the highest activity, with MIC values as low as 9.765 microg/0.5 ml against *B. cereus* and *K. pneumoniae*.

Conclusions:

• Marine algae, especially *E. intestinalis*, possess considerable antimicrobial potential.
• The acetone extract of *E. intestinalis* is a promising lead molecule for drug discovery.
• *E. intestinalis* can be developed as a novel marine antimicrobial agent.