Characterization and in vitro antioxidant activity of Albizia stipulata Boiv. gum exudates.

The objective of the present study is to characterize the physicochemical properties and to determine the in vitro antioxidant activity of Albizia stipulata Boiv. gum exudates collected from Northeast India. The total carbohydrate, uronic acid and protein contents, monosaccharide composition and the molecular weight distribution of the purified gum was determined. The powder flow property and preliminary compressibility test were performed on the dried gum exudates. Fourier transform infrared spectroscopy (FTIR) study was performed to analyze the functional groups present in the structure. Differential scanning calorimetry (DSC) and thermogravimetry (TGA/DTA) analyses were performed to study the thermal stability of the gum. The antioxidant properties of the gum were evaluated by determining 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl scavenging activities and reducing power. The total carbohydrate and protein contents of the gum were found to be 75.17±3.21% and 2.60±1.05% respectively. The viscosity of 2% aqueous solution of the gum exhibited non-Newtonian type of flow showing pH dependent swelling. Arabinose and galactose were found to be the main monosaccharides present in the gum exudates and the molecular weight distribution of the gum was also found to be polydispersed. Results from DPPH, hydroxyl scavenging and reducing power studies showed the gum possesses antioxidant properties.