Antibacterial Properties of Fucoidan from Thirteen Indian Brown Seaweeds against Various Pathogenic Bacteria

The present study aimed to evaluate the antibacterial properties of hot water extracted fucoidan from thirteen Indian brown seaweeds against various pathogenic bacteria. The agar-well diffusion method was used to assess the antibacterial test of different fucoidan. The results revealed that S. vulgare fucoidan had higher antibacterial activity against many pathogenic bacteria, while fucoidan from other brown seaweeds had the least or no antibacterial activity in comparison to S. vulgare fucoidan. Therefore, we evaluated the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and brine shrimp toxicity assay in S. vulgare fucoidan. The MIC and MBC values were found to be 1.25 mg/mL and 10 mg/mL in S. vulgare fucoidan against pathogenic bacteria. S. vulgare fucoidan were found to be nontoxic as no mortality (Artemia) was found at different fucoidan concentrations. In addition, characterizations such as ultraviolet-visible spectroscopy, fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy were studied in Sargassum vulgare fucoidan and revealed the properties of fucoidan. This study revealed that hot water extracted fucoidan may have other biological activities but not antibacterial action. Furthermore, studies may reveal the mode of action in fucoidan.