Assessment of Anti-microbial and Anti-oxidant Activities of Modified Guar Gum

Apart from drug delivery potential of polysaccharides or their chemical derivatives, some chemically modified polysaccharides particularly sulfated polysaccharides showed significant biological property. In this study, guar gum was sulfated by reacting with various ratios of CSA (chlorosulfonic acid) and pyridine to obtain the product with different degree of sulfation (DS). The sulfated guar gum derivatives were examined by FTIR, NMR and degree of sulfation analysed and were further evaluated for their potential antibacterial activity by agar diffusion method. Results obtained from the study indicated that derivatives having higher degree of sulfation exhibited moderate activity against the selected bacterial strains at 200 μg∙ml−1. However, the sulfated guar gum did not show any significant antifungal activity at any concentration studied. The sulfated guar gum demonstrated dose-dependent DPPH and H2O2 scavenging activity with maximum activity noted at 2 mg∙ml−1 concentration. The sulfation of partially oxidized guar gum caused significant improvement of antioxidant activity to that observed for non-oxidized sulfated guar gum derivative. This study revealed that the extent of sulfation and molecular weight had significant impact on antimicrobial and antioxidant activities of guar gum.